Global expression analysis of the brown alga Ectocarpus siliculosus (Phaeophyceae) reveals large-scale reprogramming of the transcriptome in response to abiotic stress.
BACKGROUND
Brown algae (Phaeophyceae) are phylogenetically distant from red and green algae and an important component of the coastal ecosystem. They have developed unique mechanisms that allow them to inhabit the intertidal zone, an environment with high levels of abiotic stress. Ectocarpus siliculosus is being established as a genetic and genomic model for the brown algal lineage, but little is known about its response to abiotic stress.


RESULTS
Here we examine the transcriptomic changes that occur during the short-term acclimation of E. siliculosus to three different abiotic stress conditions (hyposaline, hypersaline and oxidative stress). Our results show that almost 70% of the expressed genes are regulated in response to at least one of these stressors. Although there are several common elements with terrestrial plants, such as repression of growth-related genes, switching from primary production to protein and nutrient recycling processes, and induction of genes involved in vesicular trafficking, many of the stress-regulated genes are either not known to respond to stress in other organisms or are have been found exclusively in E. siliculosus.


CONCLUSIONS
This first large-scale transcriptomic study of a brown alga demonstrates that, unlike terrestrial plants, E. siliculosus undergoes extensive reprogramming of its transcriptome during the acclimation to mild abiotic stress. We identify several new genes and pathways with a putative function in the stress response and thus pave the way for more detailed investigations of the mechanisms underlying the stress tolerance of brown algae.
Dittami
Simon M
SM
UPMC Univ Paris 6, UMR 7139 Végétaux marins et Biomolécules, Station Biologique, 29680 Roscoff, France. dittami@sb-roscoff.fr
Scornet
Delphine
D
Petit
Jean-Louis
JL
Ségurens
Béatrice
B
Da Silva
Corinne
C
Corre
Erwan
E
Dondrup
Michael
M
Glatting
Karl-Heinz
KH
König
Rainer
R
Sterck
Lieven
L
Rouzé
Pierre
P
Van de Peer
Yves
Y
Cock
J Mark
JM
Boyen
Catherine
C
Tonon
Thierry
T
D000465:Algorithms; D001483:Base Sequence; D018076:DNA, Complementary / Q000096:biosynthesis; D005110:Extracellular Space / Q000378:metabolism; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation; D042541:Intracellular Space / Q000378:metabolism; D005810:Multigene Family; D020411:Oligonucleotide Array Sequence Analysis; D009994:Osmolar Concentration; D018384:Oxidative Stress / Q000235:genetics; D000459:Phaeophyceae / Q000235:genetics*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D015203:Reproducibility of Results; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012269:Ribosomal Proteins / Q000235:genetics; D054712:Salinity; D012964:Sodium / Q000378:metabolism; D013312:Stress, Physiological / Q000235:genetics*; D014158:Transcription, Genetic
D018076:DNA, Complementary; D012333:RNA, Messenger; D012269:Ribosomal Proteins; D012964:Sodium