脱落酸调控非跃变型荔枝果实成熟的分子机理研究

As an important plant endogenous hormone, abscisic acid (ABA) has strong effects inregulating the stage development and maturation of litchi fruit. Previous studies showed that ABA increased dramatically during the maturation of litchi fruit, and exogenous ABA application advance fruit maturation. Litchi, a typical non-climacteric fruit, will be used as experimental materials in this project to study the molecular mechanism of ABA regulating litchi fruit maturation based on three aspects including traditional physiology, enzyme activities and molecular biology. We intent to reveal the internal relationships between the ABA and maturation physiological processes, such as anthocyanin biosynthesis, chlorophyll degradation and sugar accumulation. And thus the mechanism of non-climacteric fruit maturation constructed more system through the explore of molecular mechanism in ABA regulating litchi fruit maturation. Hopefully, these studies will provide theoretical basis for useful practices in regulating the maturation and coloration of litchi fruit..The main work is as follows: Firstly, the correlativity will be analyzed between ABA content and physiological indexes including anthocyanin, chlorophyll and sugar. Secondly, the genes of key enzymes will be cloned in maturation processes, and their expression characteristics will be studied. Thirdly, the key genes in ABA biosynthesis also will be identified, and then their expression patterns will be clarified by comparing with ABA content. Lastly, the target enzymes of ABA will be uncovered by studying the effect of exogenous ABA and its inhibitors on enzyme activities and gene expression.

植物内源激素脱落酸（ABA）对果实成熟和后期发育具有重要的调控作用，荔枝成熟时果实中ABA含量会大幅增加，外源ABA处理也会使果实成熟提前。本项目以典型的非跃变型果实-荔枝为试材，拟从传统生理学、酶学和分子生物学等多个层面揭示ABA调控荔枝果实成熟的分子机理；通过分析ABA与花色素苷合成、叶绿素降解和糖积累等各个生理过程之间的内在联系，从理论上深化非跃变型果实成熟机理的研究，以期能为生产上调控荔枝果实成熟技术措施提供理论依据。主要研究内容如下：对果实成熟过程中ABA含量与花色素苷、蔗糖等生理指标之间相关性进行分析；克隆成熟各生理过程的关键基因，并研究他们的表达模式及与ABA的关系；克隆ABA生物合成的关键基因，结合ABA含量研究它们的表达模式特性；通过外源ABA及其抑制剂对各生理过程的关键酶活性和基因表达变化的影响，明确ABA调控果实成熟的酶学靶标。

植物内源激素脱落酸（ABA）对果实后期发育和成熟具有重要的调控作用，成熟时荔枝果实中ABA含量会大幅增加，外源ABA处理也会使果实成熟提前。项目以典型的非跃变型果实—荔枝为试材，对果实成熟过程中花色素苷、葡萄糖、蔗糖、果糖及ABA等生理指标进行了分析；对果实花色素苷合成、糖积累等生理过程的关键酶的基因进行克隆，并研究了其表达模式特性；克隆了LcNCED等ABA生物合成的关键基因，并对其时空表达特性进行了分析；通过研究利用外源ABA及其合成抑制剂对成熟相关因子的影响，对ABA合成与色泽形成、糖分积累之间的关系进行了分析；同时，用BBCH编码系统对荔枝整个发育周期的形态学特征进行了描述，开展了光调控花色素苷生物合成和裂果机制的转录组学分析。这些研究结果将有助于从传统生理学和分子生物学等两个层面对ABA调控荔枝果实成熟的分子机理进行揭示；通过分析ABA生物合成与花色素苷合成和糖积累等各个生理过程之间的内在联系，从理论上深化了对非跃变型果实成熟机理的研究，将为生产上调控荔枝果实成熟技术措施提供理论支持。