粘质沙雷氏菌中乙偶姻合成途径调控基因的鉴定

Identification of the Regulatory Gene Controlling the Acetoin Fermentation Pathway in Serratia marcescens H30

粘质沙雷氏菌H30中控制乙偶姻合成的调控因子budR被克隆和鉴定。序列分析表明调控因子budR与液化沙雷氏菌MG1中乙偶姻合成调控因子slaR同源性达80%,属lysR型调控因子。调控因子budR突变可导致粘质沙雷氏菌无法合成乙偶姻,引起培养液pH快速下降和菌体生长缓慢,而在培养过程中维持pH7.0,突变菌的生长可获得恢复,暗示budR的功能为调控粘质沙雷氏菌发酵过程中性产物乙偶姻的合成,以阻止发酵液过度酸化。

A lysR type regulatory gene, budR involved in acetoin biosynthetic pathway, was cloned and identified from Serratia marcescens H30. Sequence analysis showed that the budR gene shared 80% identities with the slaR gene from S. liquefaciens MG1. Inactivation of the budR gene could result in the absence of acetoin production accompanied with rapid acidification of the broth and entered the stationary phase in advance during the culture. However, when the culture pH was maintained at 7.0, the growth of budR mutant strain could be relieved, suggesting budR gene promoted the neutral compound （acetoin） production to counteract lethal acidification of the broth.