鱼腥蓝细菌PCC7120 alr3504基因缺失突变体的构建及表型分析

Construction of an alr3504 defected mutant and its phenotype analysis in Anabaena PCC7120

c-di-GMP是新发现的真细菌所特有的第二信使,其合成和降解由双鸟苷酸环化酶和磷酸二酯酶分别完成。经生物信息学分析,鱼腥蓝细菌PCC7120基因alr3504可能编码含有保守GGDEF结构域的双鸟苷酸环化酶。【目的】为了鉴定该基因的功能,【方法】采用标记置换方法将alr3504缺失。【结果】敲除该基因后,发现缺失突变体的形态、生长速度及异形胞发育与野生型无明显差异,但在盐胁迫条件下,突变体比野生型对钠盐更敏感。【结论】可见alr3504虽不直接影响异形胞发育,但参与了其它信号途径,研究结果为阐明蓝细菌丰富而复杂的信号转导机制奠定了基础。

C-di-GMP [Bis-（3′,5′）-cyclic dimeric guanosine monophosphate] is a novel global second messenger in bacteria. The diguanylate cyclase and phosphodiesterase involve in c-di-GMP synthesis and degradation, respectively. alr3504 in Anabaena PCC7120 possibly encodes diguanylate cyclase with a coserved GGDEF domain. [Objective] For functional characterization, [Methods] the deletion mutant of alr3504 was constructed by using marker exchange method. [Results]No significant differences were found in the cell morphology, growth rate or heterocyst development between the deletion mutant and the wild type strain. But the mutant was more sensitive to Na＋-salt under salt-stress. [Conclusion] The results show that alr3504 did not affect heterocyst development directly, but involved in other signaling pathway, which lay a foundation for exploring the abundant and complex signal transduction of cyanobacteria.