XVI International Botanical Congess
It is known that C. reinhardtii can adapt to limiting CO2 conditions by inducing a set of genes for CO2-concentrating mechanism (CCM). We have isolated high-CO2 requiring mutants by gene tagging. One of the mutants, C16 contains a single NIT1 insertion in its genome. The gene which is impaired in the C16 mutant was named Ccm1. The Ccm1 mutant is aberrant in most of the normal responses to CO2 limitation, it does not induce periplasmic carbonic anhydrase (CA), chloroplastic LIP-36 and mitochondrial CA, and does not accumulate inorganic carbon in the cells. This means that Ccm1 mutant lacks an essential gene for CO2 signal transduction to induce CCM-related genes. Structure and the possible function of Ccm1 will be presented and discussed.