影响枣果实糖积累的关键转运蛋白鉴定及驯化位点解析

Jujube (Ziziphus jujuba Mill.) is the most important economic species in Rhamnaceae. It is domesticated from wild/sour jujube (Ziziphus jujuba Mill. var. spinosa (Bunge) Hu ex H. F. Chow), in which process the sugar content of fruits increased significantly. However, the key genes and domestication sites that affect sugar accumulation remain unknown, limiting resource mining and variety breeding. Fruit sugar accumulation is closely related to the transport of sugar transporters. In our previous study, we identified 13 candidate sugar transporters through the whole genome deep resequencing of cultivated jujubes and wild ones. Based on this foundation, we identify the key sugar transporter genes which affect sugar accumulation, clarify the active region of the upstream promoter, and reveal the domestication sites with the methods of subcellular localization, sugar index determination, transcription analysis, promoter clone sequencing and promoter activity identification. These results will provide important theoretical guidance for the study of fruit domestication and provide molecular markers for breeding practice; besides, they will also provide new insights into the domestication and breeding from wild resources, contributing to breaking the degradation of economic tree species.

枣（Ziziphus jujuba Mill.）是鼠李科最重要的经济果树，由野生酸枣驯化而来。在栽培枣的驯化中，果实含糖量显著提高，但影响糖积累的关键基因及驯化位点尚不明确，限制了优异资源挖掘和品种选育。果实糖积累与糖转运蛋白的运输密切相关，前期我们筛选出13个驯化相关的候选糖转运蛋白基因。在此基础上，本项目以枣和野生酸枣群体为试材，采用亚细胞定位、高效液相色谱糖指标测定、转录表达分析、启动子克隆测序、GUS转录活性分析等实验鉴定该13个糖转运蛋白的功能及分子表达机制，明确驯化中影响糖积累的关键糖转运蛋白基因，阐明其上游启动子的调控活性区域，揭示影响枣果实糖积累的驯化位点。研究成果将为果树糖积累的研究提供重要理论指导，为育种实践提供分子标记；也为打破经济树种品种退化，从野生资源育种提供新视角。

枣（Ziziphus jujuba Mill.）是鼠李科最重要的经济果树，由野生酸枣(Ziziphus jujuba Mill. var. spinosa (Bunge) Hu ex H. F. Chow)驯化而来。在栽培枣的驯化中，果实含糖量显著提高，但影响糖积累的关键基因及驯化位点尚不明确，限制了优异资源挖掘和品种选育。果实糖积累与糖转运蛋白的运输密切相关，在本项目中，阐明ZjSWEET2.2可通过叶片糖的输出促进光合作用，且该转运蛋白受糖信号的调节。明确了 ZjSWEET15为果实库器官糖卸载的关键转运蛋白，其影响枣和低糖型酸枣果实糖积累；鉴定了ZjSWEET15上游与果实糖积累连锁的SNP/驯化位点，初步筛选了调控该基因表达的转录因子ZjAFP3。研究成果将为果树糖积累的研究提供重要理论指导，为驯化育种实践提供分子标记；也为打破经济树种品种退化，从野生资源育种提供标记基因。