外果皮特异性表达乙烯受体SlETR7调控番茄采后失水的机理研究

蜡质是影响果蔬采后失水的重要原因。研究表明乙烯能促进蜡质合成，降低果实失水；然而乙烯如何调控蜡质合成的分子机制还不明确。申请人前期研究发现，番茄乙烯受体SlETR7在外果皮中特异性高表达，其敲除突变体（Sletr7）显著抑制番茄采后失水。本研究以番茄为材料，首先比较野生型（WT）、Sletr7和过表达株系（OxSlETR7）果实失水、表皮渗透性、蜡质合成及相关基因时空表达变化的差异，明确SlETR7调控番茄表皮蜡质合成的关键时间节点；再利用RNAseq分析WT、Sletr7的外果皮和中果皮的差异表达基因，从中挖掘可能调控蜡质合成关键基因；最后，对候选基因进行功能解析，并通过表型回复实验确定候选基因与SlETR7的上下游调控关系。本研究将通过筛选并鉴定SlETR7下游调控蜡质合成的关键基因，揭示ETRs调控蜡质合成的信号途径，推动乙烯调控蜡质研究，为控制果蔬失水提供理论参考。

Wax has been shown a great inhibition to plant water-loss. Many studies indicate that ethylene induces wax synthesis at the plant epidermis tissue, reducing the amount of the water-loss. However, how ethylene regulates plant wax synthesis is still unknown. Our previous study showed that SlETR7 had a specific-and-high expression at tomato exocarp and Sletr7 knock-out mutant significant inhibited fruit water-loss. In this study, different genotype tomato (WT, Sletr7 knock out mutants, and Overexpression SlETR7 lines) will be chosen for demonstrating the effects of SlETR7 on tomato wax synthesis. At the stage of the SlETR7 induced fruit wax synthesis, the possible wax-synthesis regulatory genes will be screened by RNA-seq analysis of exocarp and mesocarp of WT and Sletr7. Then we will characterize the candidate genes by knocking out and over-expressing them in tomato. Finally, the regulation between SlETR7 and the candidate genes will be revealed by complementary experiments. This study will identify and characterize SlETR7 and candidate genes in the wax synthesis during tomato ripening and post-harvest stages, to clarify the mechanism of how ethylene involved wax synthesis, which will provide the theoretical base for the control of fruit water loss during postharvest.