基于SSRs和GBS-SNPs的枣裂果性状关联分析

Chinese jujube is a unique economic forest species that originates from China. Fruit cracking severely affects the productivity and quality of the jujube, and becomes a limiting factor for jujube industrial development. Elucidating the genetic regultion of jujube fruit cracking is of great importantance to the breeding of Chinese jujube. In this study, we will use 400 jujube cultivars planted in the experimental station to carry out association analysis for fruit cracking. Firstly, we will classify fruit cracking rate through multi-year surveilance of fruit cracking traits for all cultivars; combined with population structure analysis using SSR markers, 180 representative jujuba cultivars will be selected; secondly, we will establish a high throughput Genotyping-By-Sequencing (GBS) protocol for Chinese jujube, using which we will identify Single Nucleotide Polymorphism (SNP) for the 180 selected cultivars; thirdly, association analysis will be perfomed between SSR/ SNP markers and fruit cracking traits to locate the markers associated with fruit cracking. And a F1 population will be used to verify the obtained significant markers, which will be further annotated.This study will establish a platform for jujube association analysis for important complex traits including fruit cracking and others, help to unveil the genetic regulation for jujube fruit cracking, and lay a foundation for the molecular maker assisted breeding.

枣树是原产我国的重要经济树种，枣裂果严重影响其产量和品质，成为枣产业发展的重要制约因素，其遗传机理的解析对枣树育种具有重要意义。本项目以试验基地的400个枣树品种为材料进行枣裂果性状的关联分析：（1）通过对各个品种裂果性状的多年观测，为各品种划分裂果等级。利用现有高多态性SSR标记对所有材料进行群体结构分析，结合裂果性状分级结果，选择出有代表性的、非遗传结构的180个枣品种。（2）通过试验开发高效的枣树GBS技术体系并对180个枣品种进行GBS测定，获得SNP位点。（3）以SSRs和SNPs标记与裂果性状进行关联分析，寻找与枣裂果性状紧密连锁的分子标记，将获得的关联标记在分离群体中进行验证，并进行功能注释。该研究将建立高效的枣树关联分析技术体系，对揭示枣裂果发生的分子机制和枣树抗裂果分子标记辅助育种具有重要意义，为今后进行抗裂果早期选择奠定基础，并为枣树其他重要性状的关联分析提

枣树是原产我国的重要经济树种，枣裂果严重影响其产量和品质，成为枣产业发展的重要制约因素，枣裂果遗传机理的解析对枣树育种具有重要意义。本研究以400个枣树品种为材料，结合多年的裂果测定和已筛选出来的高多态性SSR引物得到的群体结构数据，从中选择出了有代表性的、非遗传结构的180个枣品种。通过对果实、果核和裂果等相关的 9 个重要表型性状指标的测定及统计分析，明确了枣种质的表型多样性和裂果相关性。利用简化基因组GBS技术对180个枣品种进行测序，探索出了用于枣树的GBS测序流程及SNP数据统计方法，获得了大量高质量的SNPs位点。利用SSR和SNP两种分子标记对该群体的遗传多样性和群体结构进行了评估，利用SNP标记计算了连锁不平衡程度；选择合适的关联模型进行裂果性状的全基因组关联分析，检测到8个与裂果率显著相关以及6个与裂果指数显著相关的位点。根据关联群体平均LD衰减距离，对关联的SNP标记位点进行扫描并进行功能注释，发现10个候选基因具有多种生物学功能，参与调节植物生长发育、激素信号转导、抗逆性等，它们可能通过上述功能对枣裂果产生差异性影响。本研究结果对揭示枣裂果发生的分子机制和枣树抗裂果分子标记辅助育种具有重要意义，为今后进行抗裂果早期选择奠定基础，所建立的高效的枣树关联分析技术体系能够为枣树其他重要性状，如果实大小、果实品质、抗性等的关联分析提供关键的技术借鉴。