褪黑素对葡萄果实品质调控的生理及潜在分子机理解析

Melatonin was identified in grape berries in 2006 and thereafter in wines in 2008. From the human’s point of view, the presence of melatonin in grapes and wines would further increase the nutritional value of grape berries and wines. However, the question worth noting is that why the grape itself would like to keep melatonin during the process of natural and human selection. To answer this question, the present study will choose grape clusters under field management, in vitro berries and callus to investigate the potential roles of melatonin playing in grape development and quality determination. Firstly, the spatiotemporal distribution of melatonin in various genotypes were investigated. Secondly, by modification of endogenous melatonin (via endogenous application or the transgenic strategy), the morphologic and physiology index changes were accordingly recorded to speculated the potential roles of melatonin. Thirdly, transgenic callus (containing SNAT OE, SNAT RNAi, and empty vector) will be treated with high temperature and PEG mediated drought conditions, respectively. By the transcriptome comparisons of different combinations, potential pathways and candidate genes regulating melatonin-mediated berry development and quality determination could be identified. The selected candidate genes would be further characterized by the inverse genetics approaches. The present study would also provide with the potential strategies in the improvement of berry quality and melatonin content of grapevine. Therefore, this study is of both scientific and practical interests.

褪黑素分别于2006和2008年相继在葡萄果实和葡萄酒中被检测到。尽管葡萄中褪黑素的价值从对人类健康有益的角度得到了认可，但是褪黑素的存在对葡萄自身的意义何在值得并有待探讨。本项目拟以多种葡萄材料（田间栽培果穗、离体培养果实与愈伤组织）为研究对象：首先，系统阐明褪黑素在葡萄中的含量与分布特征，研究褪黑素积累的品种与时空特异性，并进一步推测其生物功能；而后，分别通过外源褪黑素处理与转基因（SNAT OE、SNAT RNAi和空载）双重途径改变葡萄内源褪黑素含量，在生理水平上探究褪黑素对葡萄生长发育和果实品质，尤其是糖酸品质的影响；最后，通过逆境处理转基因葡萄愈伤组织，比较分析多种组合的转录组数据，并通过分子生物学手段探究褪黑素对葡萄糖酸品质的影响以及潜在的分子机理。本项目的研究也可为提高葡萄果实品质以及果实中的褪黑素含量提供潜在途径。因此，本项目的研究具有重要的理论价值和实践意义。

葡萄是世界性范围内重要的经济果树，可广泛用于鲜食、酿酒以及制干。生长环境是葡萄及其加工品产量以及品质的限制因素。盐渍化是世界上普遍影响葡萄生长发育以及产量的重要的非生物胁迫。植物进化出一系列的抵御机制去应对盐胁迫。通过转录组测序揭示葡萄应答盐胁迫的分子机制，为进一步提高葡萄的抗盐性提供理论依据。基于转录组数据，进一步开发分子标记，用于检测葡萄植株受盐胁迫的程度。同时，褪黑素与盐协同处理表明低浓度的褪黑素处理有助于提高葡萄细胞的抗盐性，相反，高浓度褪黑素处理则会加剧盐胁迫对葡萄细胞的伤害。