Abstract:

The Deinococcus radiodurans R1 potassium uptake protein encoded by ktrA gene(DR\|166), played an important role under salt and osmotic stress. The quantitative real\|time PCR assay showed that the expression of ktrA gene was up\|regulated remarkably under salt and D\|sorbitol in wild strain. Construction of D. radiodurans R1 mutants deleted ktrA gene (ΔktrA) by means of fusion PCR and homologous genetic technology. Survival rates of the ΔktrA obtained and wild strain were investigated under different concentrations of KCl and D\|Sorbitol. The results indicated that the ΔktrA were much more sensitive to KCl and D\|Sorbitol treatment comparing to that of wild type, which indicated KtrA protein played an important role when influenced by salt and osmotic stress.This research will be helpful to study the functions of ktrA gene.

Key words: D. radiodurans R1, ktrA, potassium uptake protein, fusion PCR, abiotic stress

摘要：

耐辐射异常球菌(D. radiodurans R1)ktrA基因(DR_1666)编码的K+吸收蛋白在盐胁迫和渗透胁迫中起着重要作用。采用QRT\|PCR分析表明在盐和D\|山梨糖醇胁迫条件下，野生型菌株中ktrA基因表达均显著上调。同时采用融合PCR方法和同源重组技术，构建ktrA基因缺失突变株(ΔktrA)，以野生型菌株DR做对照，分别用不同浓度的氯化钾和D\|山梨糖醇对突变株进行胁迫处理。结果显示，突变株ΔktrA对氯化钾和D\|山梨糖醇的敏感性明显高于野生型，表明ktrA基因在菌株耐受高盐和高渗透胁迫时起重要作用。该结果为深入研究D. radiodurans R1菌株中ktrA基因的功能提供了很好的基础。

关键词: 耐辐射异常球菌；ktrA基因；K+吸收蛋白；融合PCR；非生物胁迫