SlBEL11调控番茄果实类胡萝卜素代谢的分子机制

Carotenoid is an important quality characteristic of tomato fruit and an important source of vitamin A in vivo. Carotenoid accumulation in tomato fruits is regulated by transcription factor network, but the research progress is slow. The key scientific issues of carotenoid synthesis regulation are the excavation and functional identification of new transcription factors. Previous studies showed that SlBEL11 gene silencing inhibited the accumulation of carotenoids in tomato fruits, and the mature fruit was yellow, but the mechanism was unclear. Based on the SlBEL11 gene editing and over expression materials, the key nodes of carotenoid metabolism pathway regulated by the SlBEL11 were determined by metabonomics and RNA-seq. Using promoter analysis, EMSA, ChIP-qPCR and DLR, the target genes of SlBEL11 involved in the regulation of carotenoid metabolism pathway were analyzed and identified. SlBEL11 interacting protein was obtained and identified in tomato fruit yeast library, and its function was verified by virus-induced gene silencing (VIGS). Based on the above results, the molecular mechanism of SlBEL11 regulating carotenoid metabolism in tomato fruit was established.

类胡萝卜素是影响番茄果实品质的重要物质，也是体内维生素A的重要来源。番茄果实类胡萝卜素积累受到转录因子网络的调控，但研究进展缓慢，新转录因子的挖掘和功能鉴定是类胡萝卜素合成调控的关键科学问题。申请者前期研究发现SlBEL11基因沉默抑制了番茄果实类胡萝卜素的积累，成熟果实呈现黄色，但具体机制不清。本项目在获得SlBEL11基因编辑和过表达材料的基础上，通过代谢组和RNA-seq确定SlBEL11影响类胡萝卜素代谢途径的关键节点；利用启动子分析、凝胶阻滞迁移率试验（EMSA）、染色质免疫共沉淀定量PCR（ChIP-qPCR）和双荧光素报告酶试验（DLR）分析和鉴定SlBEL11参与调控类胡萝卜素代谢途径的靶基因；同时，筛选番茄果实酵母文库，获得并鉴定SlBEL11互作蛋白，利用病毒诱导基因沉默技术（VIGS）验证其功能。综合上述结果，建立SlBEL11调控番茄果实类胡萝卜素代谢的分子机制。

类胡萝卜素是影响番茄果实品质的重要物质，类胡萝卜素的摄入可预防维生素A缺乏、黄褐斑及认知功能衰退等疾病，果实类胡萝卜素的转录调控机制是本领域的研究热点。本研究通过对SlBEL11转基因番茄果实的类胡萝卜素含量及代谢途径基因表达量变化筛选靶基因，通过EMSA、DLR和VIGS方法验证SlBEL11调控类胡萝卜素代谢途径的靶基因，解析了SlBEL11调控番茄果实类胡萝卜素代谢的分子机制；在此基础上，我们还发现了SlBEL11参与调控果实成熟、果实大小、果皮厚度等重要现象，为后续研究提供了线索和基础。