新型除草剂高粱素生物合成关键酶ARS的双控表达质粒构建及表达条件优化

Dual control plasmid construction and expression optimization of Sorghum bicolor ARS for a novel sorgoleone herbicide biosynthesis

利用化感物质开发除草剂是目前新型除草剂发展的一个重要方向。高粱素是高粱中分泌的一种化感物质,可对多种杂草的生长表现出显著的抑制作用。高粱烷基间苯二酚合酶（alkylresorcinol synthase,SbARS）是高粱素生物合成的关键酶。当以大肠杆菌Escherichia coli作为宿主进行SbARS的胞内表达时,细胞破碎是其中最为费时且最昂贵的步骤之一。本研究通过构建新型双控表达质粒p BM123-ars,实现了SbARS在大肠杆菌BL21（DE3）中的温控自裂解异源表达;在此基础上,通过优化诱导表达条件,可获得最高的SbARS酶活力（相对酶活力为160.04%±8.12%）及最高的裂解率（82.81%±3.14%）。研究结果可为新型除草剂高粱素的生物合成奠定理论基础。

Allelochemicals offer great potential for the development of future herbicides. Sorgoleone is a kind of allelochemicals secreted by Sorghum bicolor. It can significantly inhibit the growth of many weeds. S. bicolor alkylresorcinol synthase（SbARS） is a key regulatory enzyme in the pathway of sorgoleone biosynthesis. When SbARS is expressed intracellularly using Escherichia coli as the host,the disruption of cell membrane can be time-consuming and costly. In this study, SbARS gene was optimized,chemically synthesized and expressed in a heat-inducible autolytic E. coli BL21（DE3）system by a novel dual control expression plasmid. After optimizing IPTG/heat-induced expression conditions, SbARS activity was found to be 160.04% ± 8.12%, and the lysis efficiency was improved to 82.81% ± 3.14%. These results would lay a foundation for the biosynthesis of new herbicide sorghum.