樱桃耐涝相关基因的分离与功能解析

Cherry is a kind of high-grade fruit widely cultivated in China. Although its root system is very shallow, it is sensitive to environmental changes. Serious economic losses often results from the destruction of cherry farms due to floods. Molecular biology methods for improving waterlogging-tolerance of cherries will have very important theoretical and practical significance. This project plans to start with the ERFs and CIPKs gene families relevant to plant stress resistance. Carbohydrate metabolism, which is closely related to the members of these two gene families and plays an essential role in the response to waterlogging stress, will be taken as the core of this study. Based on the waterlogging resistance of several domestic and overseas cherry species evaluated at an early stage. Specific species with a strong waterlogging resistance will be identified. Family members of specific waterlogging-tolerant ERFs and CIPKs genes in cherry shall be cloned to analyze their expression patterns in time and space. Their functions will be verified by the gene silencing and overexpression technology to determine the key genes for controlling the waterlogging resistance. These effects of specific waterlogging genes, the carbohydrate metabolism, as well as the consistency and correlation of the expression of root-development related gene family members on waterlogging tolerance shall be analyzed. Consequently, the responses and adjustment mechanisms of cherry when subjected to waterlogging stress will be deduced. The molecular mechanism of the strong or weak waterlogging-tolerant ability of the cherry germplasm will be clarified. The research results will lay the foundation for the molecular improvement of the waterlogging tolerance of cherry and other fruits, and we also expect to be able to create new species of cherry with improved waterlogging-tolerance.

樱桃是我国大面积栽培的高档果品，但其根系浅，对环境变化反应敏感，常因淹涝造成严重的经济损失。采取现代分子生物学手段，改良樱桃的耐涝性，具有十分重要的理论意义和应用价值。本项目拟从与植物抗逆性相关的ERFs和CIPKs基因家族入手，以与这两个基因家族成员紧密关联、并在响应淹涝胁迫中发挥重要作用的碳水化合物代谢为主线，在前期已筛选获得耐/敏涝樱桃特异资源的基础上，克隆樱桃耐涝特异ERFs和CIPKs基因家族成员，分析其时空表达模式，利用RNAi和基因超量表达技术验证其功能，确定调控樱桃耐涝性的关键基因，并通过分析樱桃特异耐涝基因与碳水化合物代谢和根系发生相关基因家族成员在淹涝胁迫下表达情况的一致性和相关性，探明樱桃应答淹涝胁迫的响应途径和调节机制，阐明樱桃种质耐涝能力强弱差异的分子机理。研究结果将为樱桃及其它果树耐涝性的分子遗传改良奠定基础，并有望获得转基因耐涝樱桃新种质。

樱桃味美形娇，营养丰富，经济效益高，是世界大面积栽培的高档果品。但其根系浅，对环境变化反应敏感，不耐涝。在樱桃栽培过程中，由于降水不均、排水不良等因素，涝害时有发生，常造成严重的经济损失。因此，采取各种手段，尤其是现代分子生物学技术，进行樱桃耐涝性的遗传改良与种质创新具有重要意义。本文以筛选出的耐涝樱桃种质‘沂蒙山樱’和敏涝樱桃种质‘矮化樱桃’为试材，建立了并优化了淹涝处理后樱桃根系RNA提取方法，克隆了与植物耐涝相关的PsERF和PsCIPK基因、与碳水化合物代谢和植株生长相关的PsPDC、PsADH、PsSUS、PsRAMY和PsEXP基因的cDNA序列，研究了淹水胁迫和恢复处理过程中上述基因在耐/敏涝樱桃种质中的时空表达特性，并通过分析樱桃PsERF和PsCIPK基因与PsPDC、PsADH、PsSUS、PsRAMY和PsEXP基因在淹涝胁迫下表达情况的一致性和相关性，初步探明了樱桃应答淹涝胁迫的响应途径和樱桃种质耐涝能力强弱差异的分子机理，即：淹涝胁迫下，樱桃植株体内乙烯不断积累，引起植株中PsERF、PsCIPK基因的表达量升高，而PsERF、PsCIPK基因的表达促进了PsPDC，PsADH和PsRAMY基因的表达，同时抑制了PsSUS和PsEXP基因的表达，以抑制植株生长和能量消耗。但随着淹涝时间的延长，耐涝樱桃体内淀粉含量出现匮乏，导致PsRAMY的基因在叶片中表达变缓，在根系中则开始降低。与此同时，乙醇发酵相关基因PsPDC，PsADH表达量开始上升，新陈代谢变缓，樱桃开始以无氧呼吸为主，以抵御淹涝所带来的伤害。在此基础上，我们将PsERF和PsCIPK基因的过表达载体转入了拟南芥以验证其功能，从而确定调控樱桃耐涝性的关键基因，为今后通过基因工程手段进樱桃耐涝性的分子遗传改良与种质创新奠定基础。