转录因子SlERF42调控番茄甾体糖苷生物碱合成的分子机理研究

生物碱是一类含氮的碱性有机化合物，对植物的正常生长和抗性有重要作用，同时也有重要药用价值。番茄是全球最重要的蔬菜作物之一，也是基础研究的模式植物。番茄中主要的生物碱是甾体糖苷生物碱，也称番茄碱，具有毒性且是果实苦涩的主要原因，但有助于植物抵抗病原菌、细菌，甚至昆虫的侵害；番茄碱的糖基化修饰可以降低其毒性。申请人通过全基因组关联分析筛选到编码糖基转移酶的GAME13和转录因子SlERF42，前期工作通过体外酶活实验证实了GAME13催化番茄碱合成途径的糖基化反应，但番茄碱合成代谢的调控机制不清楚。本项目拟对SlERF42进行功能验证，解析SlERF42结合GAME13调控番茄碱代谢的分子机理；揭示其自然变异和驯化机制，挖掘优良等位变异位点对番茄碱代谢途径进行定向改良。本研究不仅为番茄新品种培育以及遗传改良提供新的工具和材料，也为马铃薯和茄子等其他作物的营养品质改良提供理论参考和遗传资源。

Alkaloids are a type of nitrogen-containing alkaline organic compounds, which play an important role in the normal growth and resistance of plants, as well as important medicinal values. Tomato is one of the most important vegetable crops in the world and a model plant for basic research. The main alkaloid in tomato is the steroidal glycoalkaloid (SGAs), also called tomatine, which is toxic and is the main factor in the bitterness of the fruit, but it helps the plant resist pathogens, bacteria, and even insects. The glycosylation modification of SGAs can reduce its toxicity. The applicant screened GAME13 encoding glycosyltransferase and transcription factor SlERF42 through genome-wide association analysis. The previous work confirmed that GAME13 catalyzes glycosylation reaction of SGAs synthesis pathway through in vitro enzyme activity experiments, but the regulatory mechanism of SGAs synthesis and metabolism is not clear. The applicant performed SGAs quantitative analysis on 442 natural populations, and screened candidate genes related to SGAs synthesis and regulation through GWAS. This project intends to verify the function of the transcription factor SlERF42, and analyze the molecular mechanism of SlERF42 targeted binding to GAME13 to regulate the synthesis of SGAs, reveal their natural variation and domestication mechanisms, effectively excavates and utilizes the excellent allelic variation, and carry out targeted improvement of the SGAs metabolic pathway. This research not only provides new tools and materials for the cultivation and genetic improvement of new tomato varieties, but also provides theoretical references and basis for the improvement of nutritional quality of other crops such as potatoes and eggplants.