脱落酸生物合成研究进展

脱落酸作为一种抑制生长的植物激素，是平衡植物内源激素和调节生长代谢的关键因子。脱落酸具有提高作物抗旱耐盐、减少果实褐变的作用，同时可降低疟疾发病率、刺激胰岛素分泌，因此在农业和医药领域有着广阔的应用前景。相较于传统的植物提取法和化学合成法，利用微生物合成脱落酸是一种经济、可持续的来源方式。目前利用天然微生物如灰葡萄孢霉菌、蔷薇色尾孢菌等合成脱落酸的研究已经取得了诸多进展，而脱落酸的异源微生物合成研究相对较少。酿酒酵母、解脂耶氏酵母、大肠杆菌等工程菌株作为天然产物异源合成的常用宿主，具有遗传背景清晰、易于操作、便于工业化生产等优势，因此利用微生物异源合成脱落酸是一种更具潜力的生产方式。本文着重从底盘细胞的选择、关键酶的筛选与表达强化、辅因子的调节、增强前体供应及促进脱落酸外排5个方面对微生物异源合成脱落酸的研究进行综述。最后，对该领域的未来发展方向进行了展望。

Advances in abscisic acid biosynthesis

Abscisic acid, a plant hormone that inhibits growth, is a key factor in balancing plant endogenous hormones and regulating growth and metabolism. Abscisic acid can improve the drought resistance and salt tolerance of crops, reduce fruit browning, reduce the incidence rate of malaria and stimulate insulin secretion, so it has a broad application potential in agriculture and medicine. Compared with traditional plant extraction and chemical synthesis, abscisic acid synthesis by microorganisms is an economic and sustainable route. At present, a lot of progress has been made in the synthesis of abscisic acid by natural microorganisms such as Botrytis cinerea and Cercospora rosea, while the research on the synthesis of abscisic acid by engineered microorganisms is rarely reported. Saccharomyces cerevisiae, Yarrowia lipolytica and Escherichia coli are common hosts for heterologous synthesis of natural products due to their advantages of clear genetic background, easy operation and friendliness for industrial production. Therefore, the heterologous synthesis of abscisic acid by microorganisms is a more promising production method. The author reviews the research on the heterologous synthesis of abscisic acid by microorganisms from five aspects: selection of chassis cells, screening and expression enhancement of key enzymes, regulation of cofactors, enhancement of precursor supply and promotion of abscisic acid efflux. Finally, the future development direction of this field is prospected.