抄録
The defect in the Calvin cycle appears to accelerate photoinactivation of PSII. To understand its molecular mechanism, we investigated effects of glycolaldehyde (GA), which inhibits the Calvin cycle at the site of phosphoribulokinase, on the photoinactivation of PSII in Chlamydomonas reinhardtii cells. When cells were exposed to light, GA did not enhance the QA reduction but accelerated photoinactivation of PSII in the concentration-depended manner. Effect of GA on the photoinactivation was abolished in the presence of chloramphenicol. After photoinactivation treatment, the PSII activity was recovered close to the initial under low light and this recovery was inhibited by GA. GA did not affect degradation of photodamaged D1 protein or the level of psbA mRNA. However, synthesis of D1 protein de novo in chloroplasts was significantly inhibited by GA. Based on these observations, we discuss the photoinactivation mechanism caused by environmental stresses.
