Streptomyces sp. NEAU6代谢的新植物生长调节剂五谷丰素生物合成研究

五谷丰素是课题组从植物内生放线菌Streptomyces sp. NEAU6中发现的新型植物生长调节剂，具有植物生长素和细胞分裂素，显著促进植物根、芽生长的双重独特功效，对作物增产明显。五谷丰素属腺嘌呤核苷类化合物，但化学结构与商品化应用的嘌呤类细胞分裂素玉米素、6-苄氨基腺嘌呤、N6-呋喃甲基腺嘌呤等差异大，由稀有糖阿洛酮糖与腺嘌呤结合成新结构的核苷。为阐明五谷丰素的生物合成，对已完成全基因组测序的放线菌NEAU6，进行五谷丰素生物合成基因簇克隆，并经体内基因敲除与回补，明确相关的各个基因及编码蛋白的功能，重点研究生物合成途径中的阿洛酮糖表异构酶、腺嘌呤磷酸阿洛酮糖转移酶的酶催化机理，在基因和酶学水平上阐明五谷丰素的组装机理。研究有望发现酶催化的新核苷类化合物生物合成的新化学机制和新的生物合成途径，为组合生物合成与合成生物学研究获得新活性化合物，及深入研究五谷丰素的生物合成调控奠定基础。

A novel plant growth regulator wugufengin was isolated from endophytes Streptomyces sp. NEAU6 by our group. It exhibits a dual and specific functions demonstrating the bioactivities of auxin and cytokinin, which can significantly promote the growth of root and shoot. As a new adenosine derivative, wugufengin consists of an adenine and a rare sugar D-psicose, and this unique structure is significantly different with other adenine-related cytokinins including zeatin, 6-benzylaminopurine and N6-isopentenyladenine. In order to elucidate the biosynthesis of wugufengin, we intend to clone the gene cluster of wugufengin on the basis of the complete genome sequence of S. sp. NEAU6. After that, the functions of genes and proteins in sanqimycin biosynthetic pathway will be characterized by gene knockout and gene complement, especially the mechanism of D-tagatose 3-epimerase and adenine phosphoribosyl transterase. This study will hold the promise to find a new catalytic and biosynthetic mechanism of nucleoside-related compounds, and will facilitate and set the stage to biosynthetically engineer new wugufengin analogues by combinatorial biosynthesis and synthetic biology.