原核生物中S2P参与应答外界环境刺激,然而行光合作用的蓝细菌-集胞藻PCC6803的S2P同源蛋白功能未知.[目的]考察集胞藻PCC6803中S2P同源蛋白s110862是否参与外界环境刺激的应答.[方法]监测在高温和氧化胁迫的条件下sll0862基因缺失突变株与野生株在生长速率或存活率上的差异,利用水样调制叶绿素荧光仪(water-PAM,脉冲-振幅-调制叶绿素荧光仪)测量在高温和氧化胁迫的条件下突变株与野生株叶绿素荧光参数的差异,来考察其光合作用差异.[结果]sU0862突变株与野生株在正常的培养环境中生长速率并无差异,但是将sll0862突变株与野生株在48℃加热处理半小时后,sll0862突变株的存活率明显低于野生株.当初始OD730值为0.1的藻液中添加终浓度为1mmol/L双氧水的时候,sll0862突变株的生长速率比野生株明显低,而且氧化胁迫条件下突变株与野生株的调制叶绿素荧光有差异.[结论]集胞藻PCC6803中sll0862基因的缺失导致突变体对高温与氧化胁迫响应出现缺陷,提示有功能的sll0862参与响应热和氧化胁迫.研究结果为进一步阐述S2P同源蛋白sll0862在集胞藻PCC6803中的功能奠定基础.%[Objective] To explore whether the S2P homolog, sll0862 in cyanobacterium Synechocystis sp. PCC 6803 is involved in stress response. [Methods] We compared the growth curve of sll0862 mutant and the wild type under high temperature or oxidative stress. We detected chlorophyll fluorescence under heat shock or oxidative stress by water-PAM (pulse amplitude modulated fluorometry). [Results] Under normal condition of autotrophic growth, the growth curve of sll0862 mutant was similar with that of the wild type. However, after heat treatment at 48℃ for 30 minutes, the survival rate of sllO862 mutant was lower than that of the wild type. The sll0862 mutant hardly survived when incubated in 1 mmol/ L H2O2, whereas the wild type is not affected. Meanwhile, different chlorophyll fluorescence under stress between the wild type and the mutant was observed using water-PAM. [Conclusion] These results indicate that the S2P homology sll0862 plays an important role in response to heat shock and oxidative stress in cyanobacterium Synechocystis sp. PCC 6803, which provides foundation for further research of the sll0862 function and mechanism.
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