集胞藻PCC 6803类铁氧还蛋白Slr1205的功能研究

类铁氧还蛋白 (ferredoxin-like, Fd-like) 在高等植物中具有调控叶绿体发育等多种重要的生理功能，但在蓝藻中的生物功能尚未被发现。通过比较集胞藻PCC 6083编码Fd-like蛋白基因的敲除突变株Δslr1205与野生型 (WT) 在不同碳源和光周期条件下的生理生化表型，分析Slr1205在集胞藻中的功能。结果显示，在高CO2浓度自养、混合营养和光异养时，Δslr1205的生长速率低于WT，而在空气中自养条件下并无差异。与此相对应，混合营养和光异养时Δslr1205比WT的呼吸速率低，与呼吸作用密切相关的NDH-1L复合体的含量少。Δslr1205在所有测试的条件下有较高的类胡萝卜素以及偏黄的表型。这些数据表明，Fd-like蛋白Slr1205的缺失造成在碳源充足条件下的生长速率下降，这可能是由于呼吸作用下调导致供能不足。研究结果为今后深入研究蓝藻Fd-like蛋白奠定了基础，为开展光合作用和呼吸作用的调节机制研究探索了新方向。

Functional Study on Ferredoxin-like Protein Slr1205 in Synechocystis sp.PCC 6803

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 ofΔslr 1205 and WT grown under different carbon sources and photoperiod.It showed that the growth rate ofΔslr 1205 was lower than that of the WT under conditions of high CO 2 concentration autotrophy,mixotrophy and photoheterotrophy,while no significant difference was observed under air-level CO 2 autotrophic cultures.In agreement with these,Δslr 1205 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,Δslr 1205 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.