Endophytes: biocontrol killers? Sarah Dodd, Daniel Than, Stanley Bellgard and Chris Winks (LCR)...
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Transcript of Endophytes: biocontrol killers? Sarah Dodd, Daniel Than, Stanley Bellgard and Chris Winks (LCR)...
Endophytes: biocontrol killers?
Sarah Dodd, Daniel Than,
Stanley Bellgard and Chris Winks (LCR)
Rebecca Ganley (Scion)
Trevor James (AgR)
Endophytes
• All plants are infested with microbes
– Symptomless• Epiphytes/Endophytes• Balanced status of symbiosis• = Majority
– Disease• Pathogens• Unbalanced status of symbiosis
Endophyte/Plant relationship– Endophyte gains
• shelter and nutrients
– Plant cost • nutrients and resources
– (e.g. more susceptible to pests and diseases: BCAs)
– Plant gains • Growth promotion
– (enhanced nutrient uptake)
• Increased tolerance to harsh environments – (e.g. drought tolerance)
• Induced Resistance to pests and diseases (BCAs)
Endophytes – weeds and weed biocontrol
• Harry Evan’s (2007) proposed:
1.Weediness: Endophytes influence the fitness of a plant and therefore its invasiveness
2.Biocontrol: Endophytes interact with plants and/or biocontrol agents either enhancing or reducing their activity
Weed / Endophyte systems under investigation in NZ
Sclerotinia on Californian thistle
Phoma on Old Man’s Beard
Wilding Ginger Privet
Pampas
Sclerotinia on Californian thistle- a mycoherbicide
– 1. Kills entire plant– 2. Partially kills plant
– Plant recovers
– 3. No effect on plant
Aim
• To identify microbes that influence the success/failure of a pathogen biocontrol agent
• To ultimately manipulate interactions to improve consistency of weed biocontrol activity
Methods - to identify endophytes
• Culturing – isolate & identify key endophyte fungi
● DGGE - DNA profile comparisons
- endophyte fungi and bacteria - DNA sequence to identify bands (microbes)
Molecular -DGGE
• Samples are all assessed and bands(microbes) identified
• Variability between tissues/plants/fields has been assessed
Endophytic microbes from thistle (closest GenBank match)
Culturing DGGE Known biology
Fungi - AscomycotaAlternaria sp.Aureobasidium pullulansBionectria sp.Botryosphaeria laricinaCladosporium cladosporioidesCladosporium sp.Codinaeopsis sp.Colletotrichum acutatumCryptococcus rajasthanensisCurvularia sp.Cylindrocarpon sp.Davidiella tassianaEpicoccum nigrumEudarluca caricisExophiala sp.Fusarium cortaderiae Fusarium oxysporum Fusarium solani Fusarium sp. 1.Hypocrea/TrichodermaLeptodondium orchidicolaLewia infectoriaNeonectria radicola Nigrospora oryzaePhaeococcomyces chersonesosPhoma exiguaPhoma sp.Phomopsis theicolaPhomopsis sp.Pichia fermentansPlectosphaerella cucumerinaPlectosphaerella sp.Preussia isomeraPreussia sp.Pyrenochaeta terrestrisSclerotinia sp.Stachybotrys echinataStemphylium sp.Verticillium dahliaeXylariaceae sp.
L,SSL--L,S-L,S,PSL--L--LRRL,RLL,RLRL--RLL---LL-L--S,RL,S,P
LRPS-LSR-RL--RSL,S,R,PL,SR-R----L--RL,R---LRL-L,R,PR-LSL,P-
saprobepossible plant pathogen or saprobepossible plant pathogenpossible secondary pathogensaprobesaprobesaprobepossible secondary pathogenyeast-like saprobegrass pathogenpossible plant pathogensaprobesaproberust mycoparasitesaprobepossible plant pathogenpossible plant pathogenpossible plant pathogenpossible plant pathogenPossible mycopathogensaprobesaprobepossible plant pathogensaprobesaprobeplant pathogenpossible secondary pathogen or saprobePossible secondary pathogen or saprobepossible secondary pathogen or saprobeyeastplant pathogenpossible plant pathogencoprophilous saprobecoprophilous saprobeonion path/soil saprobeplant pathogensaprobesaprobeplant pathogensaprobe
Endophytic microbes from thistle (closest GenBank match)
Culturing DGGE Known biology
Fungi - BasidiomycotaBovista plumbea Ceratobasidium sp.Cyathus stercoreusExidiopsis sp.Flammulina velutipesGloeoporus dichrousKuehneromyces rostratusLangermannia giganteanLimonomyces roseipellisMelampsora laricis-populinaMycena sp. / Nolanea sp.Panaeolus sphinctrinusPeniophora pini / aurantiacaPleurotopsis longinquaPleurotus pulmonariusPuccinia chrysanthemi / carduorum Puccinia cnici-oleraceiRogersella griseliniae / Hyphodontia crustosa Schizophyllum communeTomentellopsis submollis / bresadoliana
--------------------
RRSRRLSLPLRRL,PS,RLLLRLS
saprobepossible plant pathogensaprobesaprobesaprobesaprobesaprobesaprobesaprobeplant pathogen (rust)saprobesaprobesaprobesaprobepossible plant pathogenplant pathogen (rust)plant pathogen (rust)saprobesaprobesaprobe
BacteriaPantoea sp. L,R - unknown
Testing influence of endophytes
• Glasshouse trials – assess disease developmenta) BCA + key endophyte
b) BCA - key endophyte
Preliminary glasshouse trials• Can endophytes influence Sclerotinia
disease? 1. No influence
2. Enhanced Sclerotinia disease3. Reduced Sclerotinia disease (e.g. Colletotrichum sp.)
Summary
• We now have evidence to support the theory that endophytes DO influence the activity of pathogen biocontrol agents
The Future
• Sclerotinia on Cali thistle– Identify key bacterial endophytes– Continue glasshouse testing– Identify key endophyte modes of action– Improve pathogen biocontrol agent activity
• Other plant systems– Identify key endophytes and test in
glasshouse– Endophytes and insect BCAs