Patterns of gene expression induced by oligoguluronates reveal conserved and environment-specific molecular defense responses in the brown alga Laminaria digitata.
* Until now, no information has been available on the transcriptional response to the transduction of defense signals in brown seaweeds that leads to active resistance against pathogens or grazers. * Using a polymerase chain reaction (PCR)-based, subtractive cDNA approach combined with filter arrays we demonstrated that Laminaria digitata exhibits a rapid response to oligoguluronate elicitors. The transcription levels of several genes were validated by quantitative real-time reverse-transcription PCR and further analysed using pharmacological approaches. * Fifty upregulated genes were identified by differential screening in elicited algae over a 24-h time-course. These genes were related to oxidative stress responses, production of antimicrobial secondary compounds or cell wall strengthening. Moreover, pharmacological tests showed that intracellular signal transduction is likely to involve reactive oxygen species. A new oligoguluronate-inducible vanadium-dependent haloperoxidase (vHPO), specific to iodide was also characterized. The transcription of several vHPO genes was shown to be tightly regulated. * Taken together, our data show that early transcriptional defense responses in L. digitata are similar to those in land plants but also include novel defense responses that involve tightly regulated iodine metabolism.
Cosse
Audrey
A
Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie et Curie (UPMC)-Paris 6, UMR 7139 Végétaux marins et Biomolécules, Station Biologique, BP 74, F-29682, Roscoff, France.
Potin
Philippe
P
Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie et Curie (UPMC)-Paris 6, UMR 7139 Végétaux marins et Biomolécules, Station Biologique, BP 74, F-29682, Roscoff, France.
Leblanc
Catherine
C
Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie et Curie (UPMC)-Paris 6, UMR 7139 Végétaux marins et Biomolécules, Station Biologique, BP 74, F-29682, Roscoff, France.
D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000235:genetics; D004777:Environment; D020224:Expressed Sequence Tags; D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant / Q000187:drug effects*; D015723:Gene Library; D017343:Genes, Plant; D006603:Hexuronic Acids / Q000494:pharmacology*; D007700:Kinetics; D007795:Laminaria / Q000187:drug effects / Q000235:genetics* / Q000276:immunology*; D009693:Nucleic Acid Hybridization; D020411:Oligonucleotide Array Sequence Analysis; D016897:Respiratory Burst / Q000187:drug effects; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014158:Transcription, Genetic / Q000187:drug effects
D018076:DNA, Complementary; D006603:Hexuronic Acids; C007896:guluronic acid