戈壁异常球菌冷激蛋白Csp1提高大肠杆菌盐胁迫抗性

Deinococcus gobiensis Cold Shock Protein Improves Salt Stress Tolerance of Escherichia coli

耐辐射戈壁异常球菌(Deinococcus gobiensis I-0)是本研究室分离于戈壁沙漠环境中的微生物,对辐射、氧化和干旱等非生物胁迫有超强的抗性。该菌基因组含有2个冷激蛋白编码基因(csp1,Dgo_CA1136和csp2,Dgo_PA0041),编码蛋白均具有典型的冷激蛋白家族特有的结构域。本研究以戈壁异常球菌I-0 Csp1为研究对象,研究表明Csp1能显著增强模式菌株大肠杆菌对低温、高盐、干旱等非生物胁迫的抗性;QRT-PCR分析显示在盐胁迫条件下Csp1表达菌株的海藻糖合成酶基因(otsA和otsB)表达显著上调,其降解基因(treB、treC)无显著变化。Csp1通过调控海藻糖代谢途径,促进渗透保护物的积累,可能是增强细胞盐、干旱等胁迫抗性的有效途径之一。

The Deinococcus gobiensis I -0, an extremely radiation-resistant bacterium, isolated from the Gobi, has superior resistance to abiotic stress （e. g radiation, oxidation, dehydration and so on）. The two cold-shock proteins encoded by cspl （Dgo_CAl136） and csp2 （Dgo_ PA0041 ） were identified in the complete genome sequence of D. gobiensis. In this study, we showed that D. gobiensis Cspl protected Escherichia coli cells against cold shock and other abiotic stresses such as salt and osmotic shocks. The quantitative real-time PCR assay shows that the expression of trehalose synthase （otsA, otsB） was up-regulated remarkably under salt stress in the cspl -expressing strain, while no difference in the expression of the genes involved in trehalose degradation （treB and treC）. The results suggested that Cspl caused the accumulation of the trehalose was a major feature for improving tolerance to salt stress in E. coli.