关键词: 集胞藻PCC 6803, 类铁氧还蛋白, 光合作用, 呼吸作用, NDH-1L复合体

Abstract: Ferredoxin-like (Fd-like) proteins are involved in many important physiological roles in plants, such as regulation of chloroplast development. However, their effects in cyanobacteria have not revealed. In this work, the function of Synechocystis Fd-like protein Slr1205 was analyzed by comparison of physiological and biochemical properties of Δslr1205 and WT grown under different carbon sources and photoperiod. It showed that the growth rate of Δslr1205 was lower than that of the WT under conditions of high CO2 concentration autotrophy, mixotrophy and photoheterotrophy, while no significant difference was observed under air-level CO2 autotrophic cultures. In agreement with these, Δslr1205 cells decreased the respiratory rate and accumulation of NDH-1L complex, an enzyme closely related to cellular respiration in cyanobacteria. In all our tested conditions, Δslr1205 had higher carotenoid content and yellowish phenotype compared to WT. These data suggested that lack of Fd-like protein Slr1205 led to low growth rate at adequate carbon supply, which was probably due to insufficient energy caused by down-regulation of respiration. The work provided not only the basis for further investigation of cyanobacterial Fd-like proteins, but also a new direction for understanding of regulation mechanisms of photosynthesis and respiration.

Key words: Synechocystis sp. PCC 6803, ferredoxin-like protein, photosynthesis, respiration, NDH-1L complex