基于梨全基因组关联分析筛选调控果实发育期的BRI1基因功能及其作用机制研究

There are near 100 pear cultivars in our country, and most of them are medium maturing and late maturing cultivars. Concentrated pear mature period in August and September induced the generally low price. Therefore, breeding for early maturing and good quality pears becomes the keynote of fruit structural adjustment and one of the main breeding goals. However, the mechanism to regulate fruit development period is comparatively seldom studied and is not clearly known in pears. It is difficult to guide breeding. This project is based on the re-sequencing data of natural population from 312 sand pears, and the genome wide association study was carried out. One significant candidate gene BRI1 encoding brassinosteroids receptor was predicted to associate with trait of fruit development period. Modern molecular biology methods such as transient expression in pears and transformation in tomatoes will be applied to verify the function of BRI1 for regulating fruit development period. The interaction mechanism of BRI1 will be clarified by Yeast two-hybrid system, gene co-expression by RNA-seq data and Hi-C technology. Furthermore, the genetic difference of BRI1 in early maturing and late maturing cultivars will be dug out by gene sequences. Development of molecular markers will help to improve the efficiency of early maturing pear breeding. This research will expend the theory basis of fruit development period, and provide gene resource for genetic modification and molecular markers in the trait of early maturing. It has significant meaning both in theory and in practice.

我国梨的栽培品种有近100个，以中、晚熟品种居多，集中在八九月份上市，导致价格普遍偏低，因而选育早熟的优质梨品种成为我国梨品种结构调整的重点和主要育种目标之一，但是关于梨的发育期调控机制研究相对较少，机制不明，无法有效的指导育种。本研究前期基于312份砂梨重测序数据，开展全基因组关联分析，筛选到与发育期显著相关联的候选基因BRI1（编码油菜素内酯受体），利用梨的瞬时转化、番茄稳定遗传转化等现代分子生物学方法验证BRI1调控果实发育期的功能，借助膜蛋白酵母双杂交、转录组基因共表达、Hi-C等技术预测并鉴定互作基因，明确BRI1调控机制；筛选早熟、晚熟品种中的差异遗传变异位点，发掘功能基因序列特征，开发分子检测标记，为筛选早熟梨品种提供高效的育种技术。研究有望拓展梨果实发育期调控的基础理论研究，为梨果实早熟性的遗传改良提供基因资源和分子选择标记，具有理论和实践意义。

我国梨的栽培品种以中、晚熟品种居多，集中上市导致价格普遍偏低，因而选育早熟的优质梨品种成为我国梨品种结构调整的重点和主要育种目标之一，但是关于梨的发育期调控机制研究相对较少，无法有效的指导育种。本研究利用砂梨重测序数据，开展全基因组关联分析，筛选到4个候选基因，利用梨的瞬时转化、番茄稳定遗传转化等现代分子生物学方法验证BR调控果实发育期的功能，借助Hi-C等技术预测并鉴定互作基因，明确BR调控机制；筛选到了2个在梨和番茄具有转化表型的候选基因，在早熟、晚熟品种中的差异遗传变异位点，开发分子检测标记，为筛选早熟梨品种提供高效的育种技术。研究有望拓展梨果实发育期调控的基础理论研究，为梨果实早熟性的遗传改良提供基因资源和分子选择标记，具有理论和实践意义。