ICARDA引进-小麦苗期抗旱性的全基因组关联分析  

Genome-Wide Association Study of Drought Tolerance at Seedling Stage in ICARDA-Introduced Wheat

作　　者：张颖 石婷瑞 曹瑞 潘文秋 宋卫宁[1] 王利 聂小军[1] ZHANG Ying;SHI TingRui;CAO Rui;PAN WenQiu;SONG WeiNing;WANG Li;NIE XiaoJun(College of Agronomy,Northwest A&F University/State Key Laboratory for Crop Stress Resistance and High-Efficiency Production,Yangling 712100,Shaanxi;Institute of Agricultural Resources and Environment,Shandong Academy of Agricultural Sciences/State Key Laboratory of Nutrient Use and Management,Ji’nan 250100)

机构地区：[1]西北农林科技大学农学院/作物抗逆与高效生产全国重点实验室,陕西杨凌712100 [2]山东省农业科学院农业资源与环境研究所/养分资源高效利用全国重点实验室,济南250100

出　　处：《中国农业科学》2024年第9期1658-1673,I0007-I0014,共24页Scientia Agricultura Sinica

基　　金：国家自然科学基金(U22A20457);国家重点研发计划(2021YFD1900190)。

摘　　要：【目的】干旱是限制小麦生产最主要的逆境因子之一。挖掘、鉴定优异抗旱新种质、克隆抗旱新基因,以期丰富我国小麦抗旱遗传基础,为小麦抗旱遗传改良提供材料。【方法】以198份从国际干旱地区农业研究中心(ICARDA)引进的抗旱种质为材料,采用PEG-6000模拟干旱方法,通过调查苗期干旱和正常条件下的地上部鲜重、地下部鲜重、生物量和根冠比4个性状,鉴定、评价其抗旱性,结合660K SNP芯片对其抗旱性进行全基因组关联分析,发掘抗旱性相关染色体区间及关联位点,结合干旱胁迫下根等多组织的表达量数据,筛选抗旱性相关基因,最后以强抗旱性品系IR214和干旱敏感品系IR36为材料,利用qRT-PCR方法对候选基因进行验证,并分析关键候选基因的优异单倍型。【结果】干旱胁迫下,小麦的生长发育受到显著抑制,各性状表型均显著低于正常对照,不同小麦品系间也表现出显著差异,4个性状在2种处理下均呈现正态分布,变异系数为0.363—0.760,多样性指数为0.310—0.400;基于加权隶属函数值(D值)综合评价各个品种的抗旱性,发现品系IR214的D值最大,为0.851,其次为IR92、IR213、IR235和IR218等,它们可作为新的优异抗旱种质;在此基础上,通过全基因组关联分析(genome-wide association study,GWAS),共检测到102个与4个性状抗旱系数显著关联的SNP位点,表型变异解释率范围为1.07%—38.70%,其中,与地上部鲜重相关的位点60个、地下部鲜重相关位点1个、生物量相关位点36个以及根冠比相关位点5个;基于基因组注释信息,筛选到31个抗旱相关基因,结合根等不同组织的RNA-seq数据,筛选出4个抗旱候选基因,对差异表达的候选基因进行qRT-PCR验证,鉴定到2个关键抗旱候选基因;最后,分析候选基因的单倍型效应,发现TraesCS6A02G048600的AX-86174509位点,2种基因型在抗旱性状上具有显著差异,是潜在的功能位点。【结论】�【Objective】Drought is one of the most destructive environmental stresses limiting wheat production.The novel germplasm with excellent drought tolerance as well as their candidate loci were identified and characterized to enrich the genetic basis of drought tolerance and lay a material foundation for wheat genetic improvement in China. 【Method】In this study, the drought tolerance of 198 wheat accessions introduced from International Dry Area Agriculture Research (ICARDA) were investigated at seedling stage through hydroponic method with PEG6000 simulating drought. Drought tolerance index (DTI) was calculated using the shoot fresh weight, root fresh weight, total biomass and root-shoot ratio, respectively. Genome-wide association analysis was performed using 660K SNP array genotyping to obtain the SNP loci and chromosome regions associating with drought tolerance index. Combined with the expression patterns in root and other tissues, the potential candidate genes were identified, and then they were further verified by qRT-PCR approach with the most drought-tolerant accession IR214 and the most drought-sensitive accession IR36 as materials. Finally, the excellent haplotypes of key candidate genes were analyzed. 【Result】Compared to normal control condition, the growth and development of wheat were significantly impaired under drought treatment. There were also significant phenotypic variations among different accessions with all of the four traits displayed normal distribution. The coefficient of variation ranged from 0.363 to 0.760 with genetic diversity from 0.310 to 0.400. Using the weighted membership function value (D value), the drought tolerance of these accessions was evaluated. Results showed that accession IR214 had the highest D value with 0.851, followed by IR92, IR213, IR235, and IR218, which could be considered as the novel excellent drought-tolerance germplasm. Furthermore, through genome-wide association study (GWAS) analysis, a total of 102 loci were significantly associated with the DTI

关 键 词：小麦 干旱胁迫 660K SNP芯片 全基因组关联分析 候选基因 

分 类 号：S512.1[农业科学—作物学]