Abstract
Acclimation to CO2-limiting stress is achieved by monitoring of the environmental changes through putative CO2-signal transduction pathways. Our focus is to understand how the changes in CO2 levels are sensed and the roles of low-CO2 responsive genes. Using cDNA array, we identified a gene, named as LciB, encoding a 48-kDa soluble protein, showed rapid induction during the acclimation process in low-CO2 conditions. Induction of the LciB mRNA was impaired in a mutant, ccm1, that cannot acclimate to low-CO2 conditions and LciB complemented a mutant, pmp1, lacking a part of CO2-transport activity. We generated RNAi strains that decrease the abundance of the LCIB protein and carried out a photosynthetic characterization. We also examined the subcellular localization of LCIB protein by immuno-histochemistry. Based on the above observation, it is possible that LCIB protein is associated with putative CO2-transports under low-CO2 conditions.
