International Plant Immunity Symposium...International Plant Immunity Symposium ‒ 1st IRTG 2172...

International Plant Immunity Symposium 1st IRTG 2172 PRoTECT Symposium

June 14th and 15th 2018 Tagungszentrum Alte Mensa Göttingen

Program and Abstract Booklet

International Plant Immunity Symposium ‒ 1st IRTG 2172 PRoTECT Symposium June 14th and 15th 2018, Tagungszentrum Alte Mensa Göttingen

2

Talks Adam-von-Trott-Saal, 2nd Floor

Thursday, June 14th

9:00 Ivo Feussner: Welcoming Speech

Sess

ion

1

Chair: Aswin Nair

9:10 Ljerka Kunst: Understanding the biosynthesis of the cuticle, the plant’s first barrier against pathogens and herbivores.

9:40 Milena Lewandowska: Wound-induced wax biosynthesis in A. thaliana.

10:00 Shauna Somerville: Cellulose derived oligomers acts as DAMPs and trigger defense-like responses.

10:30 Coffee break Hall Ground floor/Hall 2nd floor

Sess

ion

2

Chair: Karl Kasper

11:00 Harry Brumer: CAZymes at the plant-microbe nexus.

11:30 Athanas Guzha: Understanding the role of two Arabidopsis thaliana Glycosyl hydrolases in disease resistance.

11:50 Alga Zuccaro: Molecular mechanisms of root symbioses.

12:20 Ralph Hückelhoven: ROP GTPases are hubs of cytoskeleton and membrane dynamics in plant microbe interactions.

12:50 Lunch Hannah-Vogt-Saal/Emmy-Noether-Saal Ground floor

Sess

ion

3

Chair: Miriam Leonard

14:00 Volker Lipka: A single lineage-specific Verticillium effector triggers complex developmental reprogramming of host plant vascular tissues.

14:30 Gerhard Braus: Infection and colonization of plant hosts by Verticillium dahliae.

15:00 Christiane Gatz: The vascular pathogen Verticillium longisporum requires a jasmonic acid-independent COI1 function in roots to elicit disease symptoms in Arabidopsis shoots.

15:30 Corné Pieterse: The root microbiome and plant immunity.

16:00 Poster Session Hannah-Vogt-Saal/Emmy-Noether-Saal Ground floor

19:00 Conference Dinner Restaurant Bullerjahn, Markt 9


3

Friday, June 15th

Sess

ion

4

Chair: Jelena Budimir

8:30 Andrea Polle: Mycorrhizal reprogramming impede poplar herbivores.

9:00 Roberto Solano: Evolutionary divergence in the bioactive jasmonate in land plants.

9:30 Cara Haney: Regulation of plant growth and defense by beneficial microbes.

10:00 Kishore Vishwanathan: Defence remodeling by ectomycorrhizal fungi.

10:20 Coffee break Hall Ground floor/Hall 2nd floor

Sess

ion

5

Chair: Denise Hartken

10:50 Melissa Bredow: Mechanisms regulating plant immune homeostasis.

11:20 Kai Heimel: A conserved stress response pathway promotes effector secretion and signaling crosstalk during pathogenic development of Ustilago maydis.

11:50 Stefan Hoth: Models for studying autoimmunity and cell death.

12:20 Wanwan Liang: TIR-NB-LRR immune receptor SOC3 pairs with truncated TIR-NB protein CHS1 or TN2 to monitor SAUL1 homeostasis.

12:40 Lunch Hannah-Vogt-Saal/Emmy-Noether-Saal Ground floor

Sess

ion

6

Chair: Dmitrij Rekhter

14:00 Marcel Wiermer: NUCLEOPORIN88-regulated defense signaling in Arabidopsis.

14:30 Daniel Lüdke: The truncated NLR protein TN13 interacts with IMPORTIN-α3 and is required for disease resistance in Arabidopsis.

14:50 Di Wu: The Carboxyl-terminal tail of BAK1 is differentially required for plant development and immunity.

15:10 Ivan Baccelli: No more a xenobiotic: updating the story of β-aminobutyric acid in plant defense.

15:40 Yuelin Zhang: Opposite roles of salicylic acid receptors NPR1 and NPR3/NPR4 in transcriptional regulation of plant immunity.

16:10 Closing


4

Poster session Hannah-Vogt-Saal / Emmy-Noether-Saal Ground floor

Table of contents: Posters (ctrl + click to go to the abstract)

1. Strategies for Exploring the Functional Consequences of Pervasive Transcriptional Activity in Arabidopsis, Ryan Ard

2. Functional Analysis of Arbuscular Mycorrhiza-related Medicago truncatula ERF Transcription Factor Genes, Lisa Hartung

3. A Downy Mildew effector induces shade avoidance and suppresses plant immunity by binding to RADICAL-INDUCED CELL DEATH1, Lennart Wirthmueller

4. Six pairs of allelic MLA immune receptor - powdery mildew AVRA effectors argue for a direct non-self recognition mechanism, Isabel Saur

5. A single Verticillium dahliae effector induces de novo xylem formation in Arabidopsis leaves, Leonie Weber

6. Loss of a putative pore-forming protein leads to auto-immunity and enhanced PAMP-triggered responses in Arabidopsis thaliana, Danalyn Holmes

7. Effector-triggered forgetting: Type III-effector proteins repress plant immune memory, Tiziana Guerra

8. Characterisation of the endophytic fungus Serendipita herbamans colonizing roots of different model and non-model plants, Frank Waller

9. A small secreted protein from the Sr2/LrSV2/PM/Fhb1 locus of wheat affects resistance to Fusarium head blight and powdery mildew, Wanxin Chen

10. CRISPR/Cas9 knockout mutagenesis in Medicago truncatula transgenic roots leads to high variability in editing events, Arne C. A. Petersen

11. From precision disease phenotyping to identification of quantitative powdery mildew resistance genes, Maria Pogoda

12. TGA1/4 and ROXY9 regulate hyponastic growth, Katrin Treffon 13. Regulation of Arabidopsis thaliana chitin receptor activation and internalisation by

phosphorylation, Elena Petutschnig 14. The Xanthomonas type-III effector XopS interferes with proteasomal turnover of a WRKY

transcription factor to dampen the induction of plant defence responses, Margot Raffeiner 15. Mapping kinetics of cellular hormone signaling at sites of Hyaloperonospora arabidopsidis-

Arabidopsis thaliana interactions, Hassan Ghareeb 16. Identification of molecular components required for CERK1-4-dependent cell death

responses in Arabidopsis thaliana, Christine Trippel 17. BluVision ‒ A New Framework for Precise Phenotyping of Cereal-Pathogen Interactions,

Dimitar Douchkov 18. Extra-large G-protein 2 (XLG2) plays an important role in cerk1-4 cell death formation,

Ronja Hacke 19. Beta vulgaris resistance protein Rz2 recognizes the Beet necrotic yellow vein virus RNA2

encoded movement protein TGB1 and triggers cell death, Veronika Wetzel 20. Mitochondria and Endoplasmic Reticulum in indole glucosinolate metabolon formation and

PEN2-mediated pathogen entry control, Lena Wagenknecht 21. Functional analysis of AM-related Medicago truncatula NF-Y transcription factors, Steven

Krüger


5

22. Transcriptome analysis of the Arabidopsis nucleoporin mutants mos3/nup96 and nup160 using RNA-Seq, Denise Hartken

23. Analysis of the JA-independent COI1 Function in Arabidopsis thaliana upon Infection with Verticillium longisporum, Louisa Ulrich

24. Elucidation of the role of NLPs of Verticillium longisporum infecting crucifers, Ling Su 25. TGA1 and TGA4 Dependent gene regulation during salicylic acid activated defense signaling,

Jelena Budimir 26. Pathogen-induced cell wall remodeling and production of Danger Associated Molecular

Patterns (DAMPs), Sina Barghahn 27. Characterization of putative poplar CERK1 genes involved in chitin perception, Mascha

Brinkkötter 28. Exploring the potential crosstalk between cell wall integrity, sugar, and defence signaling,

Timo Engelsdorf 29. Proteasomal protein turnover during defence priming in Arabidopsis, Daniela Spinti 30. Host-induced gene silencing (HIGS) as a biotechnological and natural tool for controlling

cereal diseases, Karolina Słomińska-Durdasiak 31. Possible role of mitochondrial persulfide metabolism in plant pathogen response, Tatjana

Hildebrandt 32. Elucidating the role of KORRIGAN1 in Jasmonate production, Stefan Mielke 33. Chasing mycorrhizal systemic signals, Karl Kasper 34. Characterization of a Secreted, Infection-Induced Multicopper Oxidase in Ustilago maydis,

Sean W. McCotter 35. Is upregulation of the aba cascade the reason for susceptibility in TGA1TGA4 mutants? Aswin

Nair Anadath Kizhakkaveettil 36. What makes the difference? Asymptomatic and pathogenic Verticillium longisporum strains,

Jessica Starke 37. New insights into phosphate-containing sphingolipids by a LC/MS-based lipidomics platform,

Yi-Tse Liu 38. Verticillium induces the secretion of different protein patterns in response to its

environment, Miriam Leonard 39. Characterization of a pipecolic acid biosynthesis pathway required for systemic acquired

resistance, Dmitrij Rekhter 40. Specific suppression of MAP kinase activation - A novel function of the bacterial effector

protein AvrRpt2, Lennart Eschen-Lippold 41. Characterization of membrane localized plant immune receptor activation and regulation,

Sruthi Sunil 42. Oxylipins in the moss Physcomitrella patens, Hanno Resemann 43. Systematic analysis of UPR crosstalk reveals new connections to known signaling pathways,

Lara Schmitz 44. Gene expression and chromatin changes in Arabidopsis autoimmunity, Lisa Amelung 45. Lasiodiplodia theobromae cultures can be used to produce jasmonic acid and its oxidized

derivatives, Lennart Mohnicke


6

1) Ryan Ard Strategies for Exploring the Functional Consequences of Pervasive Transcriptional Activity in Arabidopsis

University of Copenhagen

Copenhagen Plant Science Centre

Bülowsvej 34

1870 Frederiksberg C

Denmark

Ryan Ard1, Maxim Ivanov1, Peter Kindgren1, Vicent Pelechano2, Sebastian Marquardt1 1Copenhagen Plant Science Centre, University of Copenhagen, Frederiksberg, Denmark 2SciLifeLab, Karolinska Institutet, Solna, Sweden

Organisms must respond favourably to frequent environmental challenges, including diverse biotic and abiotic stresses. Solutions to these challenges are instructed in genomic DNA, the bulk of which does not code for protein. Notably, RNA Polymerase II (RNAPII) pervasively transcribes genomes, resulting in a plethora of coding and non-coding RNA species. Regulated plasticity at transcription start and end sites (TSS and TES, respectively) multiplies RNAs generated from genomes, increases isoform diversity, and thus leads to possible changes in RNA stability, structure, and coding potential. By mapping discrete transcription unit boundaries across the Arabidopsis thaliana genome, we can now distinguish alternative isoforms from other overlapping non-coding transcription units. Since overlapping acts of transcription have a tendency to impinge on the activity of one another, we are interested in resolving the scale of transcriptional interference across the Arabidopsis genome. More specifically, we are characterizing how such transcriptional events help plants to rapidly and adequately respond to diverse environmental stresses. To meet these aims, we are also studying the molecular mechanisms that govern TSS selection in Arabidopsis. In particular, we find that the act of transcription into promoters represses their function in plants via transcription-dependent chromatin remodelling. Accordingly, mutant plants with compromised chromatin regulation accumulate alternative transcript isoforms, some of which encode truncated proteins with distinct cellular functions. In sum, our ongoing analyses are beginning to reveal the extent to which pervasive transcriptional activity influences dynamic gene expression and transcript isoform regulation in the context of a multicellular organism.


7

2) Lisa Hartung Functional Analysis of Arbuscular Mycorrhiza-related Medicago truncatula ERF Transcription Factor Genes

Leibniz University Hannover

Institute for Plant Genetics

Lisa Hartung, Rico Hartmann, Sascha Offermann, Natalija Hohnjec, Helge Küster

Dept. IV Plant Genome Research

Herrenhäuser Str. 2

30419 Hannover

Germany

The formation and establishment of an arbuscular mycorrhiza (AM) between Medicago truncatula and Rhizophagus irregularis is directed by a set of defined genes that undergo transcriptional reprogramming during the process (Hogekamp et al., 2011, Hogekamp and Küster, 2013). Along with other groups of transcription factors (TFs), genes of the group of ethylene responsive factors (ERFs) showed transcriptional up- or downregulations during AM. So far only MtErf1 has been shown to be directly involved in AM. Silencing the gene by artificial microRNA (amiR) under the control of the promoter of AM-specific MtPt4, R. irregularis genes were repressed (Devers et al., 2013). Silencing of the gene furthermore led to truncated and defect arbuscules. To specify the function of these TFs during AM, five AM-activated ERF-TF candidates were selected and RNAi-constructs to silence those genes were designed. The effect of the RNAi-constructs on the targeted gene and upstream regulators like RAM1 are measured by semi-quantitative real-time RT-PCR. In addition, promoter-gus-fusions are performed to investigate cellular expression of ERF-TF-promoters in transgenic roots. To identify potential interaction partners of ERF TFs like other groups of AM-regulating TFs (GRAS-, CAATbox- and Myb-TFs) either yeast-two-hybrid (Y2H) or split-YFP approaches will be performed.


8

3) Lennart Wirthmueller A Downy Mildew effector induces shade avoidance and suppresses plant immunity by binding to RADICAL-INDUCED CELL DEATH1

Freie Universität Berlin

Dahlem Centre of Plant Sciences

Department of Plant Physiology and Microbiology

Königin-Luise-Straße 12-16

14195 Berlin

Germany

Lennart Wirthmueller1, Shuta Asai2, Ghanasyam Rallapalli2, Jan Sklenar2, Georgina Fabro2, Dae Sung Kim2, Ruth Lintermann2, Pinja Jaspers3, Michael Wrzaczek3, Jaakko Kangasjärvi3, Daniel MacLean2, Frank Menke2, Mark Banfield4, Jonathan Jones2 1Dahlem Centre of Plant Sciences, Department of Plant Physiology and Microbiology, Freie Universität Berlin, Königin-Luise- Straße 12-16, 14195 Berlin, Germany 2The Sainsbury Laboratory, Norwich Research Park, Norwich NR4 7UH, UK 3Dept. of Biosciences, University of Helsinki, 00014 Helsinki, Finland 4Dept. of Biological Chemistry, John Innes Centre, Norwich Research Park, Norwich NR4 7UH, UK

The oomycete pathogen Hyaloperonospora arabidopsidis (Hpa) causes downy mildew on Arabidopsis. During infection, Hpa suppresses activation of plant innate immunity by translocating effector proteins into host cells. We report that the nuclear-localized Hpa effector HaRxL106 induces shade avoidance and attenuates salicylic acid (SA) signaling. HaRxL106 interacts with RADICAL-INDUCED CELL DEATH1 (RCD1) and HaRxL106-mediated suppression of immunity is abolished in rcd1 mutants. We report that RCD1-type proteins are phosphorylated and interact with Mut9-like kinases (MLKs) that function as phosphoregulatory nodes at the level of photoreceptors. An mlk triple mutant exhibits stronger SA-induced defense gene expression compared to wild-type plants. Our data suggest that nuclear RCD1/MLK complexes act as signaling nodes that integrate information from environmental cues and pathogen sensors, and that the Arabidopsis downy mildew pathogen targets RCD1 to prevent activation of plant immunity.


9

4) Isabel Saur

Six pairs of allelic MLA immune receptor - powdery mildew AVRA effectors argue for a direct non-self recognition mechanism

Max Planck Institute for Plant Breeding Research

Isabel M. L. Saur, Saskia Bauer, Barbara Kracher, Takaki Maekewa, Paul Schulze-Leffert

Department for Plant-Microbe Interactions

Carl-von-Linné-Weg 10

50829 Köln

Germany

The nucleotide-binding domain and leucine-rich repeat (NLR)–containing proteins in plants and animals mediate intracellular pathogen-sensing. The barley Mla disease resistance locus has been subject to extensive functional diversification in the host population and encodes numerous allelic NLRs each detecting a matching isolate-specific avirulence effector (AVRA) of the fungal pathogen Blumeria graminis f. sp. hordei (Bgh). We isolated Bgh AVRa1, AVRa13, AVRa7, AVRa9, AVRa10, and AVRa22, all encoding secreted fungal polypeptides that are recognized by allelic MLA1, MLA13, MLA7, MLA9, MLA10 and MLA22 receptors, respectively. These effectors are sequence-unrelated, except allelic AVRA10 and AVRA22 that form a balanced polymorphism in the pathogen population. Contrary to numerous examples of indirect effector recognition by plant NLRs, co-expression experiments with matching Mla-AVRa pairs indicate direct detection of unrelated fungal effectors by allelic MLA receptors.

5) Leonie Weber

A single Verticillium dahliae effector induces de novo xylem formation in Arabidopsis leaves

Georg-August-Universität Göttingen

L. Weber, K. Thole, M. Reusche, T. Teichmann, S. Dietrich, A. Poehlein, L. Faino, B. Thomma, V. Lipka

Schwann-Schleiden-Research Center for Molecular Cell Biology

Dept. for Plant Cell Biology

Julia-Lermontowa-Weg 3

37077 Göttingen

Verticillium dahliae is a soil-borne vascular plant pathogen with a wide host range. V. dahliae isolates can be subdivided into three classes regarding their interaction with Arabidopsis: chlorosis, wilting and asymptomatic. An intriguing disease symptom caused by chlorosis-class isolates is xylem hyperplasia, including transdifferentiation of bundle sheath cells into functional xylem elements. Whole genome comparison between chlorosis and wilting class reference strains coupled with RNAseq data from infected plants revealed unique coding regions in the chlorosis reference strain that show high transcriptional activity in planta. From this data, Lineage Specific Candidate Effector 2 (LSCE2) was identified. The ability to induce transdifferentiation is lost in LSCE2 knock-out mutants and can be conferred to other Verticillium strains via transgene expression. We postulate that LSCE2 acts as a fungal effector inducing transdifferentiation and consequently xylem hyperplasia in Arabidopsis.


10

6) Danalyn Holmes Loss of a putative pore-forming protein leads to auto-immunity and enhanced PAMP-triggered responses in Arabidopsis thaliana

Queen’s University

Department of Biology

116 Barrie St

K7L 3N6 Kingston

Ontario

Canada

D. R. Holmes1, M. Bredow1, K. R. Siegel1, I. Sementchoukova1, K. Thor2, S. A. Pascetta1, C. Zipfel2, J. Monaghan1,2 1Dept. of Biology, Queen’s University, 116 Barrie St, K7L 3N6, Kingston, Ontario, Canada 2The Sainsbury Laboratory, Norwich Research Park, NR4 7UH Norwich, Norfolk, United Kingdom

While animals have evolved both innate and humoral immune responses, plants rely solely on cell-autonomous innate immunity to detect and defend against infection. During infection, mammalian cells secrete pore-forming proteins that target pathogen membranes resulting in their death. The model plant Arabidopsis thaliana encodes four proteins with similarity to mammalian pore-forming proteins, however their molecular function is largely unstudied. Here we present the identification of a novel allele in one of these loci that results in enhanced PAMP-triggered responses and EDS1-dependent auto-immunity, suggesting that the predicted pore-forming protein may be guarded by a TIR-NB-LRR. We also show that this protein localizes to two sub-cellular compartments and associates with related putative pore-forming proteins. Overall, our work suggests an important role for this protein in the plant immune response.


11

7) Tiziana Guerra Effector-triggered forgetting: Type III-effector proteins repress plant immune memory

Leibniz Institute of Vegetable and Ornamental Crops (IGZ)

Tiziana Guerra and Frederik Börnke

Theodor-Echtermeyer-Weg 1

14979 Großbeeren

Germany

Pseudomonas syringae pv. tomato (Pst) DC3000 translocates approx. 30 TypeIII effectors into its plant host cell. T3 effectors function in interfering with host defense responses in order to allow disease development. However, for only few effectors the host target protein has yet been identified. The deletion of a single effectors often has no effect on bacterial virulence under laboratory conditions and thus the adaptive advantage for the bacterium in maintaining the effector remains unclear. In nature, pathogenic bacteria might barely encounter uninfected host plants and thus have to cope with primed tissues, whose enhanced defense has to be overcome. It is reasonable to assume that this situation could require other effector functions than during the infection of naïve tissue. Our study identified a first Pst DC3000 T3E repressing plant immune memory and thereby providing a growth benefit only in primed host plants. This “effector-triggered forgetting” scenario might lead to the identification of new regulators involved in immune memory.

8) Frank Waller Characterisation of the endophytic fungus Serendipita herbamans colonizing roots of different model and non-model plants

Julius-Maximilians-Universität Würzburg

Cynthia Romero, Mohamed Osman, Agnes Fekete, Martin J. Müller, Frank Waller

Julius-von-Sachs-Institute

Julius-von-Sachs-Platz 2

97082 Würzburg

Germany

Colonisation of land plants with endophytic fungi can lead to improved growth, enhanced development and enhanced resistance of host plants to abiotic stress and to pathogens. Such positive effects have been shown for the basidiomycete fungus Serendipita indica (Piriformospora indica) (Sebacinales) in several species including barley and Arabidopsis thaliana.

While S. indica was isolated in the Indian subcontinent, related species of European origin have been identified in the past years. Among them, Serendipita herbamans was isolated in Germany and was shown to enhance growth of Arabidopsis plants under controlled conditions. With the ultimate aim of using Sebacinales strains to improve plant growth and resistance in an agricultural setting, we are currently testing a variety of plant species for S. herbamans colonisation, effects on plant fitness, and for specific metabolites induced by endophytic colonisation.


12

9) Wanxin Chen

A small secreted protein from the Sr2/LrSV2/PM/Fhb1 locus of wheat affects resistance to Fusarium head blight and powdery mildew

Leibniz Institute of Plant Genetics and Crop Plant Research (IPK)

Bioinformatic Centre

Wanxin Chen1, Pete Hedley2, and Patrick Schweizer1 1Leibniz Institute of Plant Genetics and Crop Plant Research, 06466 Stadt Seeland, Germany 2James Hutton Institute, Dundee DD2 5DA, Scotland, UK

AG Pathogen Stress Genomics (PSG)

Corrensstrasse 3

06466 Stadt Seeland/OT Gatersleben

Germany

The Sr2/LrSV2/PM/Fhb1 locus of hexaploid wheat on the short arm of chromosome 3B confers quantitative resistance to stem and leaf rust, powdery mildew (PM) and Fusarium head blight (FHB). In order to find genes that are regulated by the Fhb1 QTL we profiled transcription of approximately 40,000 wheat homeologous gene groups in backcross lines that differ in absence/presence of Fhb1. This resulted in the identification of six FHB-induced candidate genes with differential, QTL-dependent expression. Four candidate genes localized to the wider Fhb1 region. Virus-induced gene silencing of one of these co-localizing genes affected FHB resistance of wheat. Because the gene is also strongly up-regulated by powdery mildew attack and since absence or presence of Fhb1 also affected powdery mildew basal resistance, we transiently expressed both the Fhb1 and fhb1 alleles, which differ in amino-acid sequence of encoded proteins, in wheat backcross lines. The results suggest that the gene candidate has opposite effects against each of the pathogens, indicating potential resistance trade off. Furthermore, allelic difference might be related to differential expression during the interaction with Fusarium culmorum, but to differential protein function in the case of the powdery mildew interaction.


13

10) Arne C. A. Petersen CRISPR/Cas9 knockout mutagenesis in Medicago truncatula transgenic roots leads to high variability in editing events


Arne C. Petersen, Daniel Nübel, Jana Vasilev, Helge Küster and Natalija Hohnjec




30419 Hannover Germany

The programmable endonuclease system known as CRISPR/Cas has been demonstrated to be a powerful tool for targeted mutagenesis that can be applied to a variety of different organisms and to nearly any genetic region. Here, we successfully used this method in Medicago truncatula, a model legume capable of forming arbuscular mycorrhiza- (AM) and nodule-symbioses, using transgenic roots induced by Rhizobium rhizogenes. Using multiple sgRNAs targeting single genes encoding AM-related GRAS-transcription factors, editing efficiencies of up to 82% were observed via PCR and subsequent sequencing analysis. Overall, CRISPR/Cas9-based editing events in M. truncatula transgenic root systems were determined to be highly variable. Although small indels were the most common type of mutation produced, larger deletions flanked by the sgRNA target sites could also be detected. In most cases, the transgenic root systems tested exhibited a mosaic pattern with a variety of different mutant alleles and even remaining wild-type alleles. In spite of that, biallelic mutations without remaining wild-type sequences were also observed. In case of the genes studied here, resulting frameshift-mutations did not lead to a decrease of mRNA abundance via nonsense-mediated decay.


14

11) Maria Pogoda From precision disease phenotyping to identification of quantitative powdery mildew resistance genes

Leibniz Institute of Plant Genetics and Crop Plant Research

Maria Pogoda, Fang Liu, Patrick Schweizer, Jochen Reif

Corrensstrasse 3

06466 Stadt Seeland / OT Gatersleben

Germany

A common leaf disease of cultivated barley (Hordeum vulgare ssp. vulgare) is powdery mildew caused by the obligate biotrophic fungus Blumeria graminis f. sp. hordei (Bgh). Infection with the fungus can lead to yield losses of up to 40 %. Our aim is the identification of new race-nonspecific resistance genes or new alleles of known genes and we address it by phenotyping of the highly diverse barley WHEALBI (“Wheat and Barley Legacy for Breeding Improvement”) collection in response to two poly-virulent Bgh isolates. We were able to identify 27 potential race-nonspecific candidate genes in our genome wide association study (GWAS) based on Exome-Capture sequencing data and our phenotypic data. An analysis of the corresponding haplotypes indicates the existence of major susceptibility and minor resistance alleles. For functional transient assays of potentially superior alleles, we decided to select the 14 most promising candidate genes.

12) Katrin Treffon TGA1/4 and ROXY9 regulate hyponastic growth


Ning Li, Katrin Treffon, Corinna Thurow, Christiane Gatz

Schwann-Schleiden Research Center for Molecular Cell Biology

Dept. for Molecular Biology and Physiology


37077 Göttingen

Germany

During low light conditions, Arabidopsis thaliana raises its leaves to a more vertical position in an attempt to reach the light. In this study, the TGA transcription factors 1 and 4 were found to activate hyponasty. Both, TGA1 and 4 interact with the CC-type glutaredoxin ROXY9 in a yeast two hybrid experiment. CC-type glutaredoxins are a plant-specific group of glutaredoxins. While their catalytic activities remain unclear, they are able to repress the functions of TGA transcription factors. Plants overexpressing ROXY9 are unable to perform hyponastic growth and ROXY9 is strongly up-regulated after backshift of low light-treated plants to normal light. This argues for a role of ROXY9 in terminating the hyponastic response. TGA1 was proposed to be a redox-modulated transcription factor. To address whether ROXY9 represses TGA1 by redox modulation, we started to analyze its redox activity in vitro.


15

13) Elena Petutschnig Regulation of Arabidopsis thaliana chitin receptor activation and internalisation by phosphorylation



Department of Plant Cell Biology


37077 Göttingen

Germany

Elena Petutschnig1, Josephine Mittendorf1, Kerstin Schmitt2, Oliver Valerius2, Andrzej Majcherczyk3, Volker Lipka1 1Albrecht-von-Haller-Institute of Plant Sciences, Department of Plant Cell Biology, Georg-August-Universität Göttingen 2Institute of Microbiology and Genetics, Department of Molecular Microbiology & Genetics, Georg-August-Universität Göttingen 3Büsgen-Institute, Molecular Wood Biotechnology and Technical Mycology, Georg-August-Universität Göttingen

In order to detect potentially pathogenic fungi, plants have evolved plasma-membrane located receptor complexes to sense the fungal cell wall polysaccharide chitin. In Arabidopsis thaliana, the chitin receptor contains two Lysin Motif (LysM) Receptor-Like Kinases (RLKs): the enzymatically active Chitin Elicitor Receptor Kinase 1 (CERK1) and the pseudokinase LysM-containing RLK5 (LYK5). Upon chitin binding, CERK1 dimerizes and autophosphorylates, which initiates chitin signal transduction. We could recently show that CERK1 also phosphorylates LYK5 in response to chitin. Subsequently, LYK5 is internalised and travels along the late endocytic route to the vacuole. Currently, we are identifying CERK1-dependent and chitin-responsive in planta phosphorylation sites by mass spectrometry. The aim is to dissect the contribution of individual phosphorylation sites on LYK5 to chitin signal transduction as well as LYK5 internalisation and trafficking.


16

14) Margot Raffeiner The Xanthomonas type-III effector XopS interferes with proteasomal turnover of a WRKY transcription factor to dampen the induction of plant defence responses

Leibniz Institute for Vegetable and Ornamental Crops (IGZ)

Theodor-Echtermeyer-Weg 1

14979 Großbeeren

Germany

Margot Raffeiner1, Tiziana Guerra1, Suayib Üstün1*, Frederik Börnke1,2 1Leibniz Institute for Vegetable and Ornamental Crops (IGZ), Großbeeren, Germany 2Institute for Biochemistry and Biology, University of Potsdam, Germany *present address: Swedish University of Agricultural Sciences, Uppsala, Sweden

In plants, WRKY transcription factors play important roles as positive and negative regulators of defence gene expression. Many Gram-negative plant pathogenic bacteria rely on so called type-III effector (T3E) proteins as virulence factors to interfere with the induction of defence responses at different levels. We show here that the T3E XopS of Xanthomonas campestris pv. vesicatoria, causal agent of bacterial spot of pepper, interacts inside the plant cell nucleus with a protein pair consisting of the transcription factor WRKY40 and an E3-ubiquitin ligase. The E3 ligase interacts with WRKY40 in vitro and in planta and ubiquitinates the transcription factor in vitro. Accordingly, transient expression in leaves of Nicotiana benthamiana suggests that WRKY40 undergoes rapid proteasomal protein turnover. However, WRKY40 protein strongly accumulates upon co-expression with XopS, indicating that XopS interferes with proteasomal turnover of WRKY40 and thus could interfere with defence gene induction that requires degradation of this negative regulator of plant defence. A possible mechanism by which XopS interferes with proteasomal turnover of WRKY40 is discussed.


17

15) Hassan Ghareeb Mapping kinetics of cellular hormone signaling at sites of Hyaloperonospora arabidopsidis-Arabidopsis thaliana interactions


Hassan Ghareeb, Mohamed El-Sayed, Michael Pound, Olena Tetyuk, Katharina Hanika, Sabine Laukamm, Volker Lipka


Department for Plant Cell Biology


37077 Göttingen

Germany

To resolve the SA, JA and JA/ET signaling activity during compatible and incompatible H. arabidopsidis-Arabidopsis thaliana interactions at cellular resolution, we have recently established reporters termed COLORFUL-SA, -JA and -JA/ET. Moreover, we developed a high-throughput platform for reporter quantification. Our results show that during the initial phase of compatible interactions SA responses are restricted to invaded mesophyll cells, whereas in incompatible interactions a pronounced SA response is confined to adjacent epidermal and mesophyll cells. In contrast, JA/ET responses exhibit reciprocal patterns, reflecting the antagonistic kinetics of the two signaling pathways. However, JA responses show distinct spatio-temporal patterns in the compatible and incompatible interactions. These findings provide unprecedented insights into hormone-dependent cell autonomous and intercellular communication processes during plant-pathogen interactions.

16) Christine Trippel

Identification of molecular components required for CERK1-4-dependent cell death responses in Arabidopsis thaliana

Georg-August Universität Göttingen

Christine Trippel, Marnie Stolze, Elena Petutschnig und Volker Lipka

Albrecht-von-Haller-Institute for Plant Sciences



37077 Göttingen

Germany

Chitin Elicitor Receptor Kinase 1 (CERK1) is a major component of the Arabidopsis chitin receptor. Accordingly, CERK1 knockout plants are defective in chitin signaling and induction of chitin-triggered immunity. A CERK1 mutant line (cerk1-4) with a point mutation in the ectodomain exhibits normal chitin signaling but shows a deregulated salicylic acid-dependent cell death reaction upon infection with Erysiphe cruciferarum. The cerk1-4 phenotype is coupled with altered CERK1 processing and increased PR1 induction upon pathogen challenge. In a forward genetic screen to identify molecular components required for cerk1-4 dependent cell death, a suppressor line showing WT-like cell death upon infection with E. cruciferarum was identified. Pathogen-induced PR1 expression in this line is also on WT level. Mapping by new generation sequencing localizes the suppressor mutation on the lower arm of chromosome 4.


18

17) Dimitar Douchkov BluVision ‒ A New Framework for Precise Phenotyping of Cereal-Pathogen Interactions

Leibniz Institute of Plant S. Lück, P. Schweizer, D. Douchkov

Genetics and Crop Plant Research (IPK)

Pathogen-Stress Genomics Group

Corrensstr. 3

06466 Seeland / OT Gatersleben

Germany

BluVision (BV) is a new framework for micro- and macrophenotyping of plant-pathogen interactions. Primarily the system was designed to cover the complete asexual life cycle of powdery mildew (PM), separated on three key stages, where each stage is covered by dedicated BV-module:

• BV-Haustoria - early interaction phenotype (IP) (haustoria formation)

• BV-Hyphae - intermediate IP (colony number, size and morphology)

• BV-Macro – late IP (infected leaf area)

Meanwhile BV was successfully tested with different pathogens such as Puccinia spp., B. sorokiniana, Fusarium spp., P. viticola. The BV-Framework consists of state of the art micro- and macroscopic imaging hardware and Artificial Intelligence based image analysis pipeline. It is designed for a high throughput phenotyping in the range of several hundreds to few thousands samples per week. Currently BV is used for phenotyping of IPK Gatersleben wheat collection (22 000 accessions) for PM resistance.

18) Ronja Hacke Extra-large G-protein 2 (XLG2) plays an important role in cerk1-4 cell death formation


Julia Anders, Ronja Hacke, Marnie Stolze, Christopher Meusel, Elena K. Petutschnig and Volker Lipka




37077 Göttingen

Chitin Elicitor Receptor Kinase 1 (CERK1) is an essential component of the Arabidopsis chitin receptor. A CERK1 mutant harbouring a single point mutation in the ectodomain (cerk1-4) shows normal chitin signaling, but an increased cell death during senescence and upon infection with non-adapted barley powdery mildew. The molecular mechanism behind the cerk1-4 phenotype is not yet understood. A forward genetic screen identified the plant-specific G-protein α-subunit XGL2 as a mediator of cerk1-4-associated cell death. Complementation studies confirmed mapping results and the functionality of a XLG2 fusion protein with an N-terminal Venus fluorescence tag. Venus-XLG2 localizes to the cell periphery and the nucleus while a mutant version retrieved from the suppressor screen localizes only to the nucleus. In this study, we want to investigate if the function of XLG2 at the cell periphery or its role in the nucleus is required for cerk1-4 cell death formation.


19

19) Veronika Wetzel Beta vulgaris resistance protein Rz2 recognizes the Beet necrotic yellow vein virus RNA2 encoded movement protein TGB1 and triggers cell death

Institute of Sugar Beet Research

Veronika Wetzel and Mark Varrelmann

Department of Phytopathology

Holtenser Landstraße 77

37079 Göttingen

Germany

The sugar beet virus disease rhizomaina is caused by the soil-borne Beet necrotic yellow vein virus (BNYVV). Plants are mainly damaged by massive proliferation of rootlets and a stunted tap root causing up to 70% yield loss. Control can only be achieved by resistant varieties carrying Rz1 and Rz2 resistance genes alone or in combination. Recently, Rz2 was identified, encoding a typical CC-NB-ARC-LRR protein, to be responsible for an infection resistance phenotype. In order to characterize pathogen recognition and response, agrobacterium infiltration assay with cDNA clones of BNYVV and Rz2 in the experimental host Nicotiana benthamiana was applied. Rapid cell-death gave indication for a hypersensitive or extreme resistance response. Remarkably, the closely related Beet soil-borne mosaic virus (BSBMV) was as well targeted by Rz2. Co-expression of all individual BNYVV and BSBMV encoded proteins in presence of Rz2 led to identification of TGB1 of both viruses as avirulence-factors.

20) Lena Wagenknecht Mitochondria and Endoplasmic Reticulum in indole glucosinolate metabolon formation and PEN2-mediated pathogen entry control


Lena Wagenknecht, Hassan Ghareeb und Volker Lipka




37077 Göttingen

Germany

Arabidopsis PENETRATION2 (PEN2) and the cytochrome P450 monooxygenase CYP81F2 are important molecular components of glucosinolate-dependent defense against powdery mildews. We recently showed that PEN2 is located in the periphery of both peroxisomes and mitochondria (Fuchs et al., Plant Cell 2016). Interestingly, subpopulations of mitochondria are recruited and arrested at sites of attempted fungal invasion, which coincides with aggregate formation of GFP-tagged PEN2 in the outer membrane of arrested mitochondria. Simultaneously, PEN2 substrate production by CYP81F2 is coordinated on the surface of the ER which becomes structurally reorganized in proximity to the immobi-lized mitochondria. Currently, we are analyzing the role of MAMP-dependent signaling for CYP81F2 expression, ER rearrangement, mitochondrial arrest and PEN2 aggregate formation.


20

21) Steven Krüger

Functional analysis of AM-related Medicago truncatula NF-Y transcription factors




Steven Krüger1, Rico Hartmann1, Damaris Arndt1; Claudia Hogekamp1, Stephanie Lauhoff1, Sascha Offermann2, Natalija Hohnjec1 and Helge Küster1 1Institute for Plant Genetics, Leibniz University Hannover 2Institute for Botany, Leibniz University Hannover


30419 Hannover

Germany

CCAAT-box binding transcription factor genes (NF-Y) are important for the regulation of a wide range of eukaryotic genes and show an especially high diversity in plants. They are arranged in heterotrimeric complexes, consisting of a NF-YA, NF-YB and NF-YC subunit each, to bind CCAAT-sequences in promoter regions and regulate gene expression. The NF-YB and NF-YC subunits contain histone-fold motifs required for general binding of the whole complex to DNA, while the NF-YA subunit contains a specific motif required for binding to the CCAAT-sequences. The multiplicity of these subunits in plants allows a high combinatorial potential to achieve a target-promoter specificity. NF-Y TF´s have been found to control nodulation in legume plants during the Rhizobium-legume symbiosis (RLS; Combier et al., 2006; Baudin et al., 2015) and some NF-Y genes have been identified via genome-wide expression analysis to be upregulated during the related arbuscular mycorrhiza symbiosis (AMS) of Medicago truncatula (Hogekamp et al., 2011; Hogekamp & Küster, 2013). Therefore, they are possible candidates as transcriptional regulators during the cellular rearrangement, the infection process, arbuscle build-up, lifespan, and degeneration during AMS.


21

22) Denise Hartken Transcriptome analysis of the Arabidopsis nucleoporin mutants mos3/nup96 and nup160 using RNA-Seq


RG Molecular Biology of Plant-Microbe Interactions


37077 Göttingen

Denise Hartken1, Daniel Lüdke1, Dimitri Stepanets2 und Marcel Wiermer1 1Department of Molecular Biology of Plant-Microbe Interaction, Georg-August-Universität Göttingen 2Department of Plant Cell Biology, Georg-August-Universität Göttingen

Germany Nucleocytoplasmic transport of proteins and RNAs occurs through nuclear pore complexes (NPCs) composed of nucleoporins (NUPs). The conserved NUP107-160 complex is the largest NPC subunit and three of its members in Arabidopsis, MOS3/NUP96, NUP160 and SEH1 are implicated in basal defense and TIR-NB-LRR mediated immunity. Our recent analyses revealed that defects in both mos3 and nup160 single mutants lead to a reduced production of reactive oxygen species (ROS) upon treatment with different pathogen-associated molecular patterns (PAMPs). MOS3 and NUP160 are also essential for nuclear mRNA export and full accumulation of transcripts encoding the defense regulator ENHANCED DISEASE SUSCEPTIBILITY1 (EDS1). We conducted a transcriptome analysis to identify additional misregulated genes in mos3 and nup160. Our RNA-Seq analysis revealed more than 400 genes that are differentially expressed in both mutant plants, including a group of plant defense genes that are currently under investigation.


22

23) Louisa Ulrich Analysis of the JA-independent COI1 Function in Arabidopsis thaliana upon Infection with Verticillium longisporum


Louisa Ulrich, Johanna Schmitz, Corinna Thurow, Christiane Gatz

Schwann-Schleiden-Research Center for molecular Cell Biology

Department of Molecular Biology and Plant Physiology


37077 Göttingen

Germany

CORONATINE INSENSITIVE 1 (COI1) is an F-box protein that functions as the receptor of the defense hormone jasmonoyl-isoleucine (JA-Ile). Here we investigate the role of COI1 in Arabidopsis thaliana infected with the root-borne hemibiotrophic fungus Verticillium longisporum. The receptor mutant ecoi but not the JA-biosynthesis mutant aos is more resistant to V. longisporum than wild type plants. COI1 but not JA-Ile is required in Arabidopsis roots to promote disease symptoms in the shoot. Comparing transcriptome data of five week old plants ten days post infection with V. longisporum or mock treatment unraveled about 200 defense-related genes constitutively expressed in ecoi that are induced in Col-0 and aos plants upon contact with V. longisporum. We postulate the observed resistance to the fungus to be mediated by genes constitutively expressed in ecoi.

24) Ling Su Elucidation of the role of NLPs of Verticillium longisporum infecting crucifers


Department of Molecular Phytopathology and Mycotoxin Research

Ling Su1, Markus Arndt1, Yuelin Zhang2, Petr Karlovsky1 1Dept. of Molecular Phytopathology and Mycotoxin Research, georg-August-Universität Göttingen 2Dept. of Botany, Micheal Smith Laboratories, University of British Columbia, Vancouver

Grisebachstrasse 6

37077 Göttingen

Germany

Necrosis and ethylene-inducing peptide 1 (Nep1)-like proteins (NLPs) are secreted by a range of bacteria, fungi, and oomycetes, including phytopathogenic species. We investigate NLPs of crucifers-pathogen Verticillium longisporum (VL), which has 8 NLP genes. We established that VlNlp1 (protein) is phytotoxic and contributes to virulence. Because some NLPs act as PAMPs, we hypothesized that VlNlp2 and VlNLP3, which are not expressed in planta, were silenced during the adaptation of VL to crucifers. VL strains overexpressing VlNlp2/3 and their GFP fusions were used to test this hypothesis. All published studies on NLPs addressed their role in pathogenicity, although the majority of NLP producers are not pathogens. To test the hypothesis that NLPs are defense proteins, we studied the effect of NLPs on predators and the expression of NLP genes upon predation. NLPs had no effect on food preference and fitness of selected predators and feeding has not affected the expression of NLP genes.


23

25) Jelena Budimir TGA1 and TGA4 Dependent gene regulation during salicylic acid activated defense signaling

Georg-August-Universität Jelena Budimir, Corinna Thurow, Christiane Gatz

Göttingen


Department of Plant Molecular Biology and Physiology


37077 Göttingen

Germany

TGA1 and TGA4 are members of TGA family of basic leucine zipper transcription factors involved in pathogen-activated immune responses. Double tga1 tga4 mutant was shown to be more susceptible than wild type plants to hemibiotrophic pathogen Pseudomonas syringae. Since TGA1 is described to be redox-modulated in SA-treated plants, the aim of this study was to identify target genes of TGA1 and TGA4 downstream of SA. In order to eliminate effects of SARD1 (SYSTEMIC AQUIRED RESISTANCE DEFICIENT 1), recently described as direct target gene of TGA1 and TGA4, on SA synthesis during the experiment, we used the SA biosynthesis mutant sid2 and the sid2 tga1 tga4 triple mutant for RNAseq analysis. We have identified 207 (8h) and 239 (24h) SA-induced genes that are less expressed in sid2 tga1 tga4 than in sid2. These genes are also less expressed in mock-treated samples, indicating that TGA1 and TGA4 are rather amplifiers of a yet unknown SA-triggered event than SA-switchable transcription factors.

26) Sina Barghahn Pathogen-induced cell wall remodeling and production of Danger Associated Molecular Patterns (DAMPs)

Georg-August-Universität Sina Barghahn, Harry Brumer, Volker Lipka

Göttingen




37077 Göttingen

Germany

The plant cell wall represents a constitutive structural barrier to microbial invasion and controls the entry success of pathogens into host tissues. Moreover, the cell wall represents a source for production of DAMPs. The best studied DAMPs to date are oligogalacturonides, which are generated upon degradation of pectic homogalacturonan. In order to identify other potential DAMPs, we recently tested a collection of commercially available plant-derived cell wall carbohydrate oligomers for their capacity to trigger plant defense responses. Interestingly, mixed-linkage glucans (MLGs) were found to robustly induce calcium influx, ROS burst and MAPK activation in different Arabidopsis ecotypes and in the crop plant barley. Notably, MLGs do not occur in cell walls of the dicot model Arabidopsis, but are abundant cell wall components of monocot grasses, including barley, as well as the fungal pathogen Rhynchosporium secalis. Thus, MLGs may function in a plant species-specific manner as DAMP or MAMP (or both).


24

27) Mascha Brinkkötter

Characterization of putative poplar CERK1 genes involved in chitin perception


Mascha Brinkkötter, Thomas Teichmann, Elena Petutschnig, Volker Lipka




37077 Göttingen

Germany

Chitin is perceived by plants as a pathogen associated molecular pattern. One major key component of the plant chitin receptor is the LysM-RLK CERK1. An in silico search in the poplar genome revealed three putative CERK1 proteins as potential chitin receptors in poplar. Chitin binding proteins were enriched via chitin affinity purification and identified by mass spectrometry. The putative LysM-RLK CERK1-like1 was the only protein of the CERK1 group which was consistently identified by unique peptides in poplar and therefore selected for further analyses. We generated a CRISPR/Cas9-mediated knockout in the poplar CERK1-like1 gene to analyze effects on chitin perception. The overexpression of a dominant CERK1-like1 variant encoding a kinase-dead CERK1-like1 is a second strategy to generate loss-of-function lines. In addition, we functionally characterize the poplar CERK1-like genes in complementation studies by transgenic expression in a chitin-insensitive Arabidopsis cerk1 knockout line.

28) Timo Engelsdorf Exploring the potential crosstalk between cell wall integrity, sugar, and defence signaling

Philipps-Universität Marburg

FB17 Department of Biology

Plant Physiology

T. Engelsdorf1, P. Gebauer2, L.M. Voll1 1Department of Biology, Plant Physiology, Philipps-Universität Marburg 2Department Phytopathology, Saxon State Company for Environment and Agriculture, Nossen

Karl-von-Frisch-Strasse 8

35043 Marburg

Germany

Leaf carbohydrate content and allocation can critically influence the outcome of plant-pathogen interactions. Periodic starvation in starch-free Arabidopsis mutants leads to altered cell wall composition and increased penetration success of the fungus Colletotrichum higginsianum. Cell wall analysis and infection experiments with cell wall mutants indicated that pectic polymers are crucial for penetration of this pathogen. After successful host colonization, reduced sugar availability leads to a reduced salicylic acid (SA) response and increased fungal growth, whereas increased sugar content causes priming of SA-dependent defence and reduced fungal growth. To identify genes required for hypersusceptibility of starch-free mutants, we chemically mutagenized pgm seeds and screened for resistance phenotypes. Candidate mutations were outcrossed to Col-0 and those mutations causing strong resistance in pgm, but weak resistance in Col-0, were selected for detailed characterization.


25

29) Daniela Spinti Proteasomal protein turnover during defence priming in Arabidopsis

University of Potsdam

Institute for Biochemistry and Biology

Karl-Liebknecht-Str. 24-25

14476 Golm

Germany

Daniela Spinti1,2, Tiziana Guerra2, Suayib Üstün2,*, Susanne Baldermann2, Frederik Börnke1,2 1Institute for Biochemistry and Biology, University of Potsdam, Germany 2Leibniz Institute for Vegetable and Ornamental Crops (IGZ), Großbeeren, Germany *present address: Swedish University of Agricultural Sciences, Uppsala, Sweden

Ubiquitin proteasome system (UPS) mediated protein turnover is involved in local and systemic immunity whereas the specific role of the UPS in systemic acquired resistance (SAR) and priming is largely unknown. The Arabidopsis mutants rtp2a-2 and rpn12a-1 are impaired in proteasome function and have been subjected to detailed molecular and phytopathological analysis during priming. Compared to wildtype Arabidopsis, both mutants show higher susceptibility and a lower capacity of being primed upon infection with Pseudomonas. According to additional preliminary results one can postulate that the defence phenotype is caused by a defect upstream of SA biosynthesis. To unravel the link between proteasomal turnover and early SA signaling we are currently analyzing global transcriptional changes via RNAseq analysis. Another crucial aspect is the identification of ubiquitinated proteins addressed by the UPS during priming. Furthermore, gene expression analyses aim to identify and characterize E3 ligases presumably involved in defence and SAR-regulating processes.


26

30) Karolina Słomińska-Durdasiak

Host-induced gene silencing (HIGS) as a biotechnological and natural tool for controlling cereal diseases

Leibniz Institute of Plant Genetics and Crop Plant

Karolina Słomińska-Durdasiak, Dimitar Douchkov, Wanxin Chen, Patrick Schweizer

Research (IPK)

Corrensstrasse 3

06466 Stadt Seeland / OT Gatersleben

Germany

HIGS, reported to act against many pathogens, might be used as a tool to control invasive fungi by RNAi-based mechanisms. The mechanism of HIGS is still not well understood, nevertheless it is proposed that fungus-specific RNA molecules are produced by host plants and are transported to the pathogen where they induce silencing of the target genes. Accumulated evidences for bidirectional cross-kingdom dsRNA trafficking between fungi and plants motivated us to examine the potential of HIGS as a naturally occurring defence mechanism in barley-Fusarium interaction. A number of natural occurring small RNA molecules from Fusarium–infected barley were chosen for functional validation. One out of the ten selected HIGS candidate genes revealed significant protection of wheat against Fusarium culmorum. To expand our knowledge about mechanism of HIGS phenomenon, genes from the silencing and secretory pathways of barley have been selected for a co-silencing experiment with a HIGS-reporter gene in powdery mildew-attacked barley to address the question, which of them affects HIGS efficiency.

31) Tatjana Hildebrandt Possible role of mitochondrial persulfide metabolism in plant pathogen response

Leibniz University Björn Heinemann, Christin Lorenz, Tatjana Hildebrandt

Hannover


Department of Plant Proteomics


30419 Hannover

Germany

The mitochondrial sulfur dioxygenase ETHE1 oxidizes persulfide groups to sulfite, which is rapidly converted to the less reactive and thus non-toxic sulfur intermediate thiosulfate by the action of a sulfurtransferase. These reactions are part of a cysteine degradation pathway and essential for reduced sulfur homeostasis. Knockout of the sulfur dioxygenase is embryo-lethal in Arabidopsis, indicating an important function during early embryo development. Knockdown plants are less tolerant against carbohydrate starvation than the wild type showing cell death and early senescence under light limiting growth conditions. Characterization of the mutant plants revealed that ETHE1 might have a function in hormone signaling during the establishment of pathogen defense reactions.


27

32) Stefan Mielke Elucidating the role of KORRIGAN1 in Jasmonate production

Leibniz Institute for Plant Biochemistry Halle

Stefan Mielke, Marlene Zimmer and Debora Gasperini

Department of Molecular Signal Processing

Weinberg 3

06120 Halle / Saale

Germany

Plant cells are surrounded by cell walls that sustain, protect them and act as the immediate contact surface with the extracellular environment. Perturbations in cell walls often lead to misregulated hormonal responses, including jasmonate (JA) accumulation, a crucial regulator of defense and growth. However, it is still unknown how cell wall-derived signals are transduced intracellularly to initiate JA production. We uncovered that Arabidopsis mutants in KORRIGAN1 (KOR1), a membrane-bound endo-glucanase involved in cellulose biosynthesis, exhibit elevated JA levels specifically in roots. To identify components involved in sensing cell wall alterations and initiating intracellular JA production, we screened for suppressors of JA in kor1, and isolated several new players. The functional characterization of those is in progress, which will lead to a better understanding of how plants sense and decode extracellular stimuli to initiate acclimation responses.

33) Karl Kasper Chasing mycorrhizal systemic signals


Büsgen Institute

Department of Forest Botany and Tree Physiology

Karl Kasper1, Andrzej Majcherczyk2, Ursula Kües2, Andrea Polle1 1Dept. of Forest Botany and Tree Physiology, Georg-August Universität Göttingen

2Dept. of Molecular Wood Technology and Technical Mycology, Georg-August Universität Göttingen

Büsgenweg 2

37077 Göttingen

Germany

Mycorrhizal fungi form associations with plant roots and have a strong impact on plant performance. We found that in the presence of mycorrhizal roots, poplar (Populus x canescens) shifts its leaf defense from phenol-based to N-bearing metabolites, such as aldoximes. As the consequence, the fitness of herbivores was reduced. This finding implies that a systemic signal triggered by mycorrhizal fungi at roots must have reached leaves. We hypothesize that the xylem sap contains such signaling compound. Here we report first results of the proteomic composition of poplar xylem saps.


28

34) Sean W. McCotter Characterization of a Secreted, Infection-Induced Multicopper Oxidase in Ustilago maydis

University of British Columbia

Michael Smith Laboratories

301-2185 East Mall

Vancouver, B.C.

V6T 1Z4

Canada

Sean McCotter1,2, Matthias Kretschmer1, Jennifer Geddes3, Daniel Croll4, James Kronstad1,2 1Michael Smith Laboratories, University of British Columbia, Vancouver BC 2Department of Microbiology and Immunology, University of British Columbia, Vancouver BC 3Department of Molecular and Cellular Biology, University of Guelph, Guelph ON 4Laboratory of Evolutionary Genetics, Université de Neuchâtel, Neuchâtel, Switzerland

Multicopper oxidases (MCOs) are blue copper proteins that catalyze oxidation reactions via transfer of electrons to copper centers. Examples include ascorbate oxidases, ferroxidases and laccases. In the maize pathogen Ustilago maydis, MCOs are virulence factors due to their roles in melanization and iron uptake. The U. maydis genome encodes 5 distinct MCOs. Proteomics data show significant enrichment of a secreted U. maydis MCO in proteinase K treated chloroplast at 2, 5, and 7 days post-infection (dpi). The corresponding transcript is significantly upregulated at 10 dpi. Knockout mutants for this gene do not differ significantly in virulence from WT. A GFP-tagged version of the gene driven by the hxt1 promoter was integrated into strain SG200 at the ip locus. Fluorescence microscopy shows punctate GFP signal in mutant cells. In a melanization assay, cultures exhibit altered pigmentation compared to the parental strain SG200, suggesting a contribution to melanin formation.


29

35) Aswin Nair Anadath Kizhakkaveettil

Is upregulation of the aba cascade the reason for susceptibility in TGA1TGA4 mutants?

Georg-August-Universität Aswin Nair, Jelena Budimir, Corinna Thurow, Christiane Gatz

Göttingen


Department of Plant Molecular Biology and Physiology


37077 Göttingen

Germany

TGA transcription factors TGA1 and 4 contribute to plant immunity by regulating SYSTEMIC ACQUIRED RESISTANCE 1 (SARD1).Gene expression analysis show that a sector of genes that are negative regulators of immunity and inducible by the phytohormone Abscisic acid (ABA) is up regulated in naive tga1tga4 mutant. It is known that TGA1 interacts with the ABA receptor PYRABACTIN RESISTANCE-1 like 6 (PYL6). Based on these observations we speculate two possibilities that could explain the link between TGA and ABA signaling during immune response: 1) Pathogen infection leads to the accumulation of ABA which acts via PYL6 to block TGA1 from activating immune response through SARD1, or 2) PYL6 is repressed by TGA1; conditions leading to the inactivation of TGA1 leads to derepression of PYL6 which regulates gene expression via components of the ABA signaling cascade, or via other transcription factors. Data addressing these hypotheses will be presented.

36) Jessica Starke What makes the difference? Asymptomatic and pathogenic Verticillium longisporum strains


Institute for Microbiology and Genetics

Department of Molecular Microbiology and Genetics

Grisebachstr. 8

Jessica Starke1, Rebekka Harting1, Susanna A. Braus-Stromeyer1, Harald Kusch1, Rabea Schlüter2, Gerhard Braus1 1Dept. of Molecular Microbiology and Genetics, Institute of Microbiology and Genetics and Goettingen Center for Molecular Biosciences (GZMB), Georg-August Universität Göttingen 2Institute of Microbiology, Ernst-Moritz-Arndt-University of Greifswald

37077 Göttingen

Germany

Successful adaptation of filamentous plant colonizing fungi to their host plants is based on genomic evolution. Verticillium longisporum is an interspecific hybrid which evolved from two haploid parental lineages and thereby adapted to rapeseed as a host plant. Comparison of pathogenic and asymptomatic V. longisporum strains isolated from rapeseed fields in the same area in Germany revealed no differences in root invasion but differences in the subsequent colonization of the plant. Genomic comparison of the two strains indicates differences in the genetic synteny and the amount and size of chromosomes due to reshuffling. The genomes contain only few lineage specific (LS) genes. Deletion of an approx. 20kb LS region of the pathogen led to an increase of induced disease symptoms in rapeseed plants.


30

37) Yi-Tse Liu New insights into phosphate-containing sphingolipids by a LC/MS-based lipidomics platform



Department of Plant Biochemistry

Justus-von-Liebig-Weg 11

37077 Göttingen

Germany

Yi-Tse Liu1, Cornelia Herrfurth1,2, Ivo Feussner1,2,3 1Albrecht-von-Haller-Institute for Plant Sciences, Dept. of Plant Biochemistry, Georg-August-Universität Göttingen 2Göttingen Center for Molecular Biosciences (GZMB), Göttingen Metabolomics and Lipidomics Laboratory, Georg-August-Universität Göttingen 3Göttingen Center for Molecular Biosciences (GZMB), Department of Plant Biochemistry, Georg-August-Universität Göttingen

Lipids are essential biomolecules, which contribute to membrane formation, signaling pathways, and energy storage. To elucidate their roles in biological processes, liquid chromatography-mass spectrometry (LC/MS) is widely used as a method to profile plant lipid composition. For further improvement of existing workflows, a lipidomics platform based on a single monophasic extraction step was established with a broad coverage of 23 lipid classes including glycerolipids, sphingolipids, and sterols. However, many phosphorylated lipid classes involved in regulatory processes are hardly covered by any global lipidomics analysis due to their low endogenous abundance. Phosphorylated sphingolipids, for instance, including long-chain base phosphates (LCB-P) and ceramide phosphates (Cer-P) play key roles in mediating cell proliferation and survival. Here, we present a solution to include these lipids into our LC/MS-based workflow that allows detailed species profiling of LCB-P and Cer-P in Arabidopsis leaves. Optimized derivatization of the molecules assists the electron-spray ionization process for the MS-analysis and enables the species-specific fragmentation for semi-quantitative detection by multiple reaction monitoring analysis. Moreover, this protocol can be integrated into many established lipidomics workflows. In summary, the improvement of the lipidomics platform for phosphorylated sphingolipids enhances the analysis of the composition of minor lipid classes and supports further functional studies in case of membrane dynamics and signaling pathways.


31

38) Miriam Leonard Verticillium induces the secretion of different protein patterns in response to its environment




Grisebachstraße 8

Miriam A. Leonard1, Rebekka Harting1, Tri-Thuc Bui1, Anika Kühn1, Oliver Valerius1, Kirstin Feussner2, Ivo Feussner2, Susanna A. Braus-Stromeyer1, Gerhard H. Braus1 1Dept. of Molecular Microbiology and Genetics, Georg-August-Universität Göttingen 2Albrecht-von-Haller-Institute, Dept. of Plant Biochemistry, Georg-August-Universität Göttingen

37077 Göttingen

Germany

Verticillia are important plant vascular pathogens that secrete specific distinct protein patterns in different nutritional environments. Exoproteome patterns of the allodiploid Verticillium longisporum were analyzed and compared. Minimal and complete media deliver a similar broad exoprotein pattern. A distinct secretion pattern is triggered in pectin-rich medium including mostly substrate-degrading enzymes. A third distinct pattern consisting of a small set of proteins including carbohydrate-active enzymes, peptidases and potential known effectors, was exclusively expressed in xylem sap corresponding to the environment during colonization. These results demonstrate that the fungus senses different environments and induces at least three different responses. Sensing requires signal transduction pathways and regulators within the cell and we currently concentrate on regulators at the interphase between filamentous growth and microsclerotia formation using the haploid V. dahliae as a tool.


32

39) Dmitrij Rekhter Characterization of a pipecolic acid biosynthesis pathway required for systemic acquired resistance





37077 Göttingen

Dmitrij Rekhter1, Pingtao Ding2, Yuli Ding2, Kirstin Feussner1, Sven Haroth1, Yuelin Zhang2, Ivo Feussner1,3 1Albrecht-von-Haller-Institute for Plant Sciences, Dept. of Plant Biochemistry, Georg-August-Universität Göttingen 2Dept. of Botany, University of British Columbia Vancouver, BC 3Göttingen Center for Molecular Biosciences (GZMB), Dept. of Plant Biochemistry, Georg-August-Universität Göttingen

Germany Systemic acquired resistance (SAR) is an immune response induced in the distal parts of plants following defense activation in local tissue. Pipecolic acid (Pip) accumulation orchestrates SAR and local resistance responses. Here we report the identification and characterization of SAR-Deficient 4 (SARD4), which encodes a critical enzyme for Pip biosynthesis in Arabidopsis. Loss of function of SARD4 leads to reduced Pip levels and accumulation of a Pip precursor, Δ1-piperideine-2-carboxylic acid (P2C). In E. coli, expression of the aminotransferase AGD2-LIKE DEFENSE RESPONSE PROTEIN 1 (ALD1) leads to production of P2C and addition of SARD4 results in Pip production, suggesting that a Pip biosynthesis pathway can be reconstituted in bacteria by co-expression of ALD1 and SARD4. In vitro experiments showed that ALD1 can use L-lysine as a substrate to produce P2C and P2C is converted to Pip by SARD4. Analysis of sard4 mutant plants showed that SARD4 is required for SAR as well as enhanced pathogen resistance conditioned by overexpression of the so far not characterized SAR regulator FLAVIN-DEPENDENT MONOOXYGENASE 1 (FMO1).


33

40) Lennart Eschen-Lippold Specific suppression of MAP kinase activation - A novel function of the bacterial effector protein AvrRpt2

Leibniz Institute of Plant Biochemistry

Lennart Eschen-Lippold, Dierk Scheel, Justin Lee

Department of Stress- and Developmental Biology

Weinberg 3

06120 Halle / Saale

Germany

Mitogen-activated protein kinase (MAPK) cascades are central regulators of diverse developmental, stress, and defense signaling pathways in plants. Upon recognition of invading pathogens or treatment with pathogen-associated molecular patterns (PAMPs), at least four MAPKs are rapidly activated (MPK3, MPK4, MPK6, MPK11) that target diverse substrate proteins for phosphorylation. This post-translational modification represents a crucial mechanism to regulate protein abundance, activity and expression. To interfere with defense signalling and to modify the cellular homeostasis in their favour, the attacking pathogens evolved mechanisms to directly deliver effector molecules into the host cells that target specific signalling components. Several bacterial effectors were described to interfere with MAPK activation. As an example, HopAI1 targets MPK3, MPK4 and MPK6 to inactivate them by removing the phosphate group from the threonine in the TEY motif. We previously identified a novel function of the Pseudomonas syringae effector protein AvrRpt2, which specifically suppresses PAMP-induced activation of MPK4 and MPK11, but not of MPK3 and MPK6. Several defense-related responses are affected in AvrRpt2-expressing plants, correlating with enhanced susceptibility against Pseudomonas syringae and Botrytis cinerea. Our work now focusses on the understanding of the underlying molecular mechanism. For this purpose, we screened several putative AvrRpt2 homologs from different plant- or soil-associated bacteria for MPK4/MPK11-suppression activity. Additionally, we analyse the role of AvrRpt2’s protease activity for the specific MPK4/11 suppression.


34

41) Sruthi Sunil Characterization of membrane localized plant immune receptor activation and regulation

Eberhard-Karls-Universität Tübingen

Sruthi Sunil, Franziska Wilhelm, Elke Sauberzweig, Christel Kulibaba-Mattern, Farid El Kasmi

Centre for Molecular Biology of Plants (ZMBP)

Auf der Morgenstelle 32

72076 Tübingen

Germany

Plants have evolved a highly specialized immune system to defend themselves against pathogens. Plant intracellular NOD-like immune receptors, (NLRs), perceive pathogen-derived effector proteins either directly or indirectly and activate a strong effector-triggered immune response (ETI). Some NLRs have a cytosolic localization and upon activation translocate to the nucleus in order to initiate the transcriptional reprogramming necessary for ETI. However, there are a number of NLRs that are supposedly membrane localized and thus might not translocate to the nucleus upon activation. How these NLRs signal to initiate an ETI is not well known. We aim to characterize how membrane-localized NLRs are regulated and what are their signaling partners. We identified a truncated endomembrane-localized NLR, PM5, which induces a strong cell death (auto-active) in Nicotiana benthamiana. Interestingly, the domain missing in PM5 is the N-terminal coil-coiled domain which is necessary for immune signaling of other full-length NLRs. PM5 and its neighboring gene, a sequence-related full-length NLR, are members of a small sub cluster of paired and putative membrane-localized NLRs. We are currently analyzing the molecular mechanisms of PM5 auto activity and whether the paired NLR’s interact genetically and physically to regulate (auto)-immunity. This project will advance our understanding of the wide modes of NLR function, by elucidating core principles of membrane NLR activity and regulation.


35

42) Hanno Resemann Oxylipins in the moss Physcomitrella patens

Georg-August-University Hanno Resemann, Kirstin Feussner, Ivo Feussner

Göttingen


Department for Plant Biochemistry


37077 Göttingen

Germany

Oxylipins are a class of metabolites that derive mostly from hydroperoxides of unsaturated fatty acids. They are formed either via chemical oxidation or catalyzed by enzymes like lipoxygenases (LOX). Oxylipins function as signaling molecules in response to external stresses in plants. One of the most prominent oxylipins is the plant hormone jasmonic acid (JA) which is coordinating the response against necrotrophic pathogens and herbivores that feed on plant leaves. Synthesis of JA occurs via the LOX-pathway from α-linolenic acid through the action of the enzymes allene oxide synthase (AOS) and allene oxide cyclase (AOC). JA can be found in most flowering plants, including Arabidopsis thaliana, and accumulates in plants whose leaves were wounded. In Physcomitrella patens, a bryophyte and model organism for non-vascular plants, synthesis of JA seems to be only partially established. Although a number of enzymes of the LOX-pathway are present in P. patens, it seems that only the plastidic part of the pathway is present, since only precursor metabolites until 12-oxo-phytodienoic acid (12-OPDA) accumulate upon mechanical wounding. Similar to JA, 12-OPDA was also shown in flowering plants to act as a signaling molecule in response to stress. In order to identify additional oxylipins and even metabolites of 12-OPDA that accumulate in wounded P. patens tissue, a non-targeted metabolomics study was conducted. Using UHPLC-ESI-TOF-MS together with the analytic software toolbox MarVis we analyzed wild type samples and knockout lines of the genes PpAOS1 and PpAOS2, which are homologues to AOS from flowering plants. Beside functionalized 12-OPDA derivatives, several unknown oxylipins accumulated upon wounding in these mutants. They probably derive from the same precursors as 12-OPDA and were further analyzed using MS-MS fragmentation techniques. Together our data support previous studies that a pathway downstream of 12-OPDA leading to formation of JA does not exist in P. patens, but these novel oxylipins may represent an archaic variant of the JA pathway which was lost in flowering plants, but is still present in mosses and possibly also in other early land plants.


36

43) Lara Schmitz Systematic analysis of UPR crosstalk reveals new connections to known signaling pathways

Georg-August-Universität Lara Schmitz, Kai Heimel

Göttingen



Grisebachstraße 8

37077 Göttingen

Germany

In the corn smut fungus Ustilago maydis, secretion of effector molecules causes ER stress and requires activation of the conserved unfolded protein response (UPR) pathway to ensure ER homeostasis. Importantly, UPR activation triggers proliferation in planta whereas ectopic UPR activation interferes with pathogenic development prior to plant penetration. MAPK/PKA signaling pathways controlling conjugation tube-formation and filamentous growth are repressed by an active UPR. Potential signaling hubs connecting the UPR and MAPK-/PKA-pathways were systemically investigated. UPR activation results in strongly decreased abundance of phosphorylated MAPK Kpp2 in dependence of the dual-specific phosphatase Rok1. Constitutive expression of key regulators downstream of Kpp2 did not restore filamentous growth or target gene expression. We hypothesize that a multilayered network mediates communication of signaling pathways and presumably adaptation to varying plant environments.

44) Lisa Amelung Gene expression and chromatin changes in Arabidopsis autoimmunity

Universität Hamburg

Institute for Plant Science

Lisa Amelung, Linn von Pein, Jennifer Deke, Jan Knop, Hümeyra Husseini, Julia Kehr, Stefan Hoth

and Microbiology

Ohnhorststrasse 18

22609 Hamburg

Germany

Regulators of PTI are targeted by pathogen effectors to inhibit defense. However, cytosolic immune receptors guard these positive regulators to initiate ETI upon effector recognition. We have established saul1 mutants as a model for autoimmunity. These plants show reduced growth, defense gene expression, and lesions in all aboveground organs. Recently, we have shown that SAUL1 is guarded by immune receptor SOC3. Taken together, this makes saul1 a good model to study gene expression and chromatin changes in autoimmunity. We have used RNA-Seq to resolve the gene expression changes in low temperature-induced autoimmunity. Few early genes were regulated after 1-2 hours, whereas hundreds of genes were changed after 3-6 hours. For identification of chromatin changes, we will monitor DNA methylation and perform ChIP-Seq. We are also aiming at identifying changes in histone modification. To this end, we established new protocols for the isolation of histones and for the purification of H3.


37

45) Lennart Mohnicke Lasiodiplodia theobromae cultures can be used to produce jasmonic acid and its oxidized derivatives




Lennart Mohnike1, Sven Haroth1, Felipe Eng1,2, Kirstin Feussner1, Ivo Feussner1 1Albrecht-von-Haller-Institute for Plant Sciences, Department of Plant Biochemistry, Georg-August-Universität Göttingen 2Cuban Research Institute on Sugar Cane Byproducts, San Miguel del Padrón, Havana, Cuba


37077 Göttingen

Germany

Jasmonic acid (JA) is a lipid-derived plant hormone, which is produced in high amounts by the fungus Lasiodiplodia theobromae via submerged fermentation. The physiological benefits of its autonomous JA-production are still elusive, but from a technological perspective, JA is a valuable feed stock since JA and its derivatives serve as important ingredients in different cosmetic and non-cosmetic products. Therefore, a deeper understanding of the JA-metabolism of L. theobromae and the optimization of the production of JA and its derivatives are of commercial interest. JA-production of L. theobromae sp. strain 2334 was first optimized in respect to the culture volume as well as surface area. Using optimal culture conditions 1.25 g JA per liter culture filtrate were obtained. Besides JA and its precursor oxo-pentenyl-cyclopentane-butanoic acid, different oxidized JA-derivatives, like 11/12-hydroxy-JA, dihydro-JA and dihydroxy-dihydro-JA were identified by high-resolution MS/MS analysis in the culture filtrate. Together, our data suggest that fungal JA-metabolism involves metabolic routes similar to those in plants. Following identification, extraction, and purification of JA-derivatives was optimized. For this purpose, different thin layer chromatography and high performance liquid chromatography (HPLC) methods were developed and optimized. So far, JA and 12-hydroxy-JA could be isolated as pure substances with yields of around 30%. HPLC-purifications for more compounds of the culture filtrate are under development.


38

For organizational and financial support, we thank our collaboration partners and sponsors


39

Your hosts: The PhD students of IRTG 2172 PRoTECT

Aswin Nair Anadath Kizhakkaveettil

Sina Barghahn

Jelena Budimir

Athanas Guzha

Sven Haroth


40

Denise Hartken

Karl Kasper

Miriam Leonard

Milena Lewandowska

Daniel Lüdke


41

Dmitrij Rekhter

Lara Schmitz

Jessica Starke

Ling Su

Kishore Vishwanathan


42

Impressum:

IRTG 2172 PRoTECT

Prof. Ivo Feußner


37077 Göttingen

Germany

[email protected]

Thursday, June 14th10:30 Coffee break Hall Ground floor/Hall 2nd floor12:50 Lunch Hannah-Vogt-Saal/Emmy-Noether-Saal Ground floor16:00 Poster Session Hannah-Vogt-Saal/Emmy-Noether-Saal Ground floor19:00 Conference Dinner Restaurant Bullerjahn, Markt 9Friday, June 15th10:20 Coffee break Hall Ground floor/Hall 2nd floor12:40 Lunch Hannah-Vogt-Saal/Emmy-Noether-Saal Ground floor

International Plant Immunity Symposium...International Plant Immunity Symposium ‒ 1st IRTG 2172...

Documents

Transcript of International Plant Immunity Symposium...International Plant Immunity Symposium ‒ 1st IRTG 2172...