梨MSP/msp基因调控自交不亲和性分子机制的研究

Self-incompatibility (SI) is a widespread genetic mechanism in fruit trees in Rosaceae. Bred varieties presented self-compatibility are an effective way to overcome self-sterile and to protect/promote fruit yield. Based on the previous studies, sequencing of genomic, transcriptomic and proteomic has been conducted in pear. Luckily, one candidate gene, MSP/msp, which maybe regulate self-incompatibility in pear, was isolated by analyzing the sequencing data. The objective of this project is to clarify how is this gene to regulate self-incompatibility in pear by developing a series of research works, including relationship between MSP/msp and SI, effect of MSP/msp interacted with stylar S-RNase, and identification of MSP/msp functioned in SI reaction. Finally, molecular mechanism of self-incompatibility regulated by the MSP/msp gene will be unraveled in pear. In addition, molecular markers tagging the MSP/msp gene can be developed to serve as molecular tools for genetic modification in pear cultivars.

自交不亲和是蔷薇科果树普遍存在的一种遗传机制，培育出自交亲和品种是克服梨自花不结实、保障和提高梨树产量的有效途径。本项目在已有研究基础上，分析了梨基因组、转录组和蛋白组测试数据间的关联性，分离出1个参与调控梨自交不亲和的候选基因（MSP/msp），拟计划开展梨MSP/msp基因与自交不亲和性的关联性、MSP/msp与花柱S-RNase蛋白的互作效应、以及MSP/msp基因在自交不亲和反应中的功能鉴定等一系列研究，从而明确MSP/msp在梨自交不亲和反应中的具体功能及其作用方式，阐明MSP/msp调控梨自交不亲和反应的分子机制，同时，发掘MSP/msp的等位变异与分子标签，为自交亲和梨品种的遗传改良提供理论依据和分子工具。

自交不亲和是蔷薇科果树普遍存在的一种遗传机制，培育出自交亲和品种是克服梨自花不结实、保障和提高梨树产量的有效途径。本项目以自交不亲和品种‘鸭梨’及其芽变的自交亲和品种‘金坠’梨为主要研究材料，明确了响应自交不亲和反应的MSP/msp基因由两个LRX基因（PbLRX.A2.1和PbLRX.A2.2）组成。这两个基因在花粉中高表达，在叶片中低表达，而在其它组织中不表达。PbLRX.A2.1和PbLRX.A2.2均能够正向调控花粉管的生长，在S-RNase抑制的花粉管中下调，说明S-RNase通过抑制PbLRX.A2.1和PbLRX.A2.2表达阻碍了花粉管的正常生长。PbLRX.A2.1和PbLRX.A2.2基因在梨基因组中均表现出双拷贝，说明这两个基因为同源基因，而不是等位基因。PbLRX.A2.1能够通过稳定S-RNase胁迫下花粉管微丝骨架结构缓解S-RNase对花粉管生长的抑制作用。此外，结合‘金坠’梨自交和杂交后代植株的自交不亲和性与简化基因组测序结果，获取了59个与‘金坠’梨自交亲和性状紧密连锁的SNP标记，这为梨自交亲和性品种的选育提供了分子工具。