AP2/ERF转录调控柑橘果实脱绿的机制

Citrus is a bulk fruit originated from China, with a large number of planting area and yeild. However, there is a phenomenon in production that fruit maturation with a poor peel color characterized by the presence of chlorophyll, it seriously affect fruit appearance quality and reduce commodity value. Previously, we isolated 126 CitAP2/ERFs basing on the citrus genome database, and characterized CitERF13 could in vivo transactivate the promoters of CitNYC and CitPPH. Based on the previous study, transcriptional regulation roles of CitAP2/ERF gene(s) and co-regulation of different members of CitAP2/ERF genes will be analyzed with dual-luciferase system and yeast one/two hybrid system. The function of CitAP2/ERF in citrus fruit degradation will be characterized with transient expression and transgenic study. The results of the present project will enrich the basic theory of citrus fruit degradation induced by ethylene, and add new content to the molecular biology of fruit tree, and provide new approach to genetic engineering breeding for fruit color.

柑橘是我国大宗水果，种植面积和产量均居前列，但生产中存在果实着色不佳等现象，严重影响果实的外观品质，降低其商品价值。前期已利用柑橘基因组数据库鉴别出126个CitAP2/ERF基因，发现CitERF13可转录激活脱绿靶标基因CitNYC和CitPPH启动子活性。本项目拟在前期研究基础上，采用双荧光素酶体系、酵母单杂交技术、瞬时表达和转基因等手段进一步系统挖掘参与果实脱绿的CitAP2/ERF新成员，并探究CitERF13与新成员之间相互作用关系及其协同介导柑橘果实脱绿转录调控生物学效应的内在机制，可丰富柑橘乙烯脱绿的基础理论，为果树分子生物学增添新内容，并为果实色泽的基因工程育种提供新途径。

柑橘是我国大宗水果，种植面积和产量均居前列，但生产中存在果实着色不佳、采后脱绿不均匀的现象，严重影响其外观品质，降低其商品价值。乙烯或乙烯利是改善柑橘果实色泽的良好途径，但是乙烯调控柑橘果实脱绿的分子机制鲜见报道。本项目采用双荧光素酶、酵母单杂交、EMSA、瞬时表达和转基因等先进技术，通过对柑橘CitAP2/ERF家族全基因组筛选，挖掘出乙烯信号转导通路CitERF6转录因子能够激活叶绿素降解途径CitPPH基因启动子的活性；鉴别了CitERF6在烟草叶片稳定遗传和在‘椪柑’果实瞬时过量表达均导致叶绿素快速降解的基因功能；阐明了乙烯是CitERF6和CitERF13启动子活化的触发剂，而这两者之间的自我激活和相互激活是维持乙烯诱导脱绿这一生物学效应的重要内在机制。通过本项目的实施，发表了SCI论文3篇，影响因子均大于3，入选“ESI高被引论文”1篇；培养了研究生4名；晋升高级职称2人；相关延续内容获批国家自然科学基金面上项目1项和省科技厅国际合作项目1项；项目负责人获得“天府英才”和“蓉漂青年创新人才”等称号。本项目丰富了柑橘果实乙烯脱绿的基础理论，为果树分子生物学增添了新内容，并为果实色泽的基因工程育种提供了新途径，具有重要的科学意义和应用前景。