Abstract
When CO2 supply is limited, aquatic photosynthetic organisms induce the carbon-concentrating mechanism (CCM) that facilitates CO2 uptake to maintain photosynthesis. By using an open gas analysis system, we showed that a multicellular green alga, Volvox carteri, induces the CCM under CO2-limiting conditions. Although it has been reported that a regulatory factor CCM1 (CrCCM1) is indispensable for induction of the CCM in a unicellular green alga, Chlamydomonas reinhardtii , the structure-function relationship of the CCM1 is poorly understood, because of lack of information on orthologues in other organisms. We have isolated a gene encoding for the CCM1 orthologue from V. carteri (VcCCM1), which shows 51.1% sequence identity with CrCCM1. There were two shared conserved regions: an N- and a C-terminal. Detail analyses focusing on these regions and complementation test using VcCCM1 in the C. reinhardtii ccm1 mutant are to be presented.
