Oxidative stress in seaweeds

Oxidative stress in seaweeds

Jonas COLLÉN

UMR 7139 –Catherine BOYENVégétaux marins et biomolécules

Station Biologique de Roscoff

Intertidal seaweeds and oxidative stressThe intertidal is harsh, dynamic, and non-predictable

→ A high stress environment

Seawater can be depleted of CO2 and supersaturated with O2

→ Potential for high ROS production during photosynthesis

Seawater contains high concentrations of halides → Formation of reactive halogens, e.g. Br & I

Seawater can be both a source and a sink of ROSSeaweeds lack roots, xylem/phloem, cuticle

→ High rate of desiccation and local phenomena

Reproductive structures are often photosynthetically active

Three principal models

Ectocarpus siliculosus

Laminaria digitata

Chondrus crispus

Seaweeds and oxidative stress-principal present research areas

Stress physiology of Chondrus crispus

Glutathione S-transferases in red and brown algae

Roles of oxylipins in macroalgae

Osmotic stress in Ectocarpus siliculosus

Effects of heavy metals on brown algal physiology

Defense reactions in brown algae

Stress physiology of Chondrus crispus-a transcriptomic approach

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Clustering of HSPs

Induction by H2O2, oxylipins,herbicides & metals

Glutathione S-transferases in red and brown algae-seaweeds contain new classes

Phylogeny

A new class

The GST, found in all organisms, are best known for their major roles in detoxification

Protein production––

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Species Source GSTsChondrus ESTs 3 Laminaria ESTs 4Ectocarpus ESTs + 15

genome

Laminaria digitata Chondrus crispus

Abiotic and biotic stress (copper, endophytic alga)

Roles of oxylipins in macroalgae-mechanisms and signaling

Expected results- Verification of known oxylipins metabolic pathways - Identification of new enzymatic activities/oxylipins pathways- Regulation of the oxylipin pathways- Evolution of lipid signalling mechanisms in eukaryotes

Characterisation of enzymes Transcriptomic profiling Metabolite profiling

Integration of results

Genomic resources(ESTs genomes) Algal tissues

Production of plant-like (C18) and animal-like (C20) oxygenated PUFA derivatives+ new molecules?

Effects of heavy metals on brown algal physiology-the example copper and Ectocarpus

Toxicology

Proteomics

Transcriptomics- Increased expression of HSP, GST, MSR, TRX

Lipidomics- Production of oxylipinsand free fatty acids

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8.99e3Cone Voltage 39

32.18 39.78 72.68

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32.18 39.78 72.68



33.99

27.142.5633.11

72.3369.4634.6940.08 45.29



72.5634.81

2.50 29.7225.1522.75

22.05 27.20

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69.58

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38.79 45.7550.03 54.59

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80.2924h 300 Cu2+ µg/L

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500 g

Effects of heavy metals on brown algal physiology -the example copper and Ectocarpus

ToxicologyProteomics: 2D analysisTranscriptomics- Increased expression of HSP, GST, methionine sulfoxide reductase, thioredoxinLipidomics- Biosynthesis of oxylipinsand free fatty acids release

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CO1 1: Scan AP- TIC


32.18 39.78 72.68



33.99

27.142.5633.11

72.3369.4634.6940.08 45.29



72.5634.81

2.50 29.7225.1522.75

22.05 27.20

34.40

69.58

40.37

38.79 45.7550.03 54.59

73.79

80.29

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CO1 1: Scan AP- TIC


32.18 39.78 72.68



33.99

27.142.5633.11

72.3369.4634.6940.08 45.29



72.5634.81

2.50 29.7225.1522.75

22.05 27.20

34.40

69.58

40.37

38.79 45.7550.03 54.59

73.79

80.29

24h 300 Cu2+ µg/L

0 g

500 g

Osmotic stress in Ectocarpus siliculosus-an integrative approach

MutagenesisHigh

salinity

Low salinity

Screening:photosynthesis

& survival

Sensitive and

resistant mutants

Transcriptomics: microarray Physiology & metabolic profiling

Pigments

[Na+] and [K+]

Intracellular osmolarity

Amino acids

Osmolytes

Photosynthesis

Integrative approach

Candidate genes

Targeted studies

Sequence data(ESTs, genome)

OSMOTIC S T R E S S

Understanding of osmotic stress responses

Ectocarpus

Defense reactions in brown algae -Laminaria produces an oxidative burst after elicitation

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G-G-G-G-G-Cell wall damage

H2O2 release

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2O2)

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Grazers, microbesendophyte attack

Alginate degradation

Control

Elicited

Hours after elicitation

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Haloperoxidases as anti-oxidant enzymes?

Haloperoxidases provides potential antimicrobial compounds

2n v

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X- + H2O2

XHO

Reactive halogensHalogenated compounds

HPO HPO

Defense reactions in brown algae -halogen metabolism in Laminaria

Perspectives

Genome of Ectocarpus– Genome sequenced (11x coverage) and assembled.

Genome of Chondrus– Pilot genome project started, 1.3x sequenced.

New more powerful tools

From gene and expression to structure and function

The peopleFunctional genomics

Catherine BOYENJonas COLLÉNSimon DITTAMIP-O DE FRANCOCécile HERVÉSylvie ROUSVOALThierry TONON

Defense and signaling in marine algaePhilippe POTINAudrey COSSELudovic DELAGE Catherine LEBLANCAndres RITTERJean-Pierre SALAÜNFrançois THOMAS

Oxidative stress in seaweeds

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