Abstract
Marine diatom is the most successful algae, which is responsible for 25% of global primary production. However, CO2-response in marine diatoms is yet not studied extensively at molecular levels. In this study, in order to understand CO2-response in marine diatoms, CO2-responsive genes were screened by cDNA-AFLP (cDNA-amplified fragment length polymorphism) analysis, which compared cDNA populations between those from cells of the marine diatom phaeodactylum tricornutum grown in 0.5 % CO2 and air. CO2-responses of 49 cDNA fragments were so far confirmed. Of these, 28 fragments, including some genes which encode Calvin-cycle related protein (phosphoglycerate kinase and transketrase), were repressed in air. On the other hand, the remaining 21 genes, including some genes which encode nitrogen-fixation system related and amino-acid synthesis systems related protein (ferredoxin nitrite reductase and ammonia dependent asparagine synthetase), were induced in air. We also will discuss some homologues of known CCM-related genes in cyanobacteria and green algae.
