【摘要】 在实验室的纯培养条件下,检测不到百脉根根瘤菌自体诱导物的产生,但是通过基因序列同源性比对分析发现,百脉根根瘤菌基因组中至少含有4种自体诱导物合成酶基因;将其中一个自体诱导物合成酶基因ml4543克隆到大肠杆菌表达载体pET30a,构建得到能异源表达该基因的大肠杆菌重组菌株;对该大肠杆菌重组菌株进行自体诱导物检测发现,该合成酶基因在大肠杆菌中能合成至少3种自体诱导物因子。更多还原

【Abstract】 Although the autoinducers of Mesorhizobium loti could not be detected under the conditions of experimentally pure culture, and even adding some root exact of Lotus japonicus into the medium in which M. loti grew to detect the acyl-homoserine lactone (AHL) production, no positive result has been available. However, analysis of homologous comparison showed that there were at least four annotated acylated homoserine lactone (AHL) synthase genes from M. loti genome sequences. The amino acids of all these four genes showed different homologous to those of luxⅠ, traⅠ and laxⅠ all of which were AHL synthase genes and have been studied most before. By cloned into the expression vector of pET30a and transformed into Escherichia coli BL21, one of these synthase genes, ml4543 was overexpressed in E. coli, and a strong 20kDa protein band could be got by SDS-PAGE of the recombinant cells. It has been detected that at least three different AHLs were produced in the recombinant strain with IPTG induced. These results indicated that M. loti has the quorum sensing system and it may work under some specific growth conditions, most likely involved in the microbe-plant interaction. This study means to give some clues to any further study of the quorum sensing system of M.loti.更多还原