中国农业科学 ›› 2024, Vol. 57 ›› Issue (9): 1658-1673.doi: 10.3864/j.issn.0578-1752.2024.09.004

• 专题:小麦抗旱性鉴定及基因资源挖掘 • 上一篇    下一篇

ICARDA引进-小麦苗期抗旱性的全基因组关联分析

张颖1(), 石婷瑞1, 曹瑞1, 潘文秋1, 宋卫宁1, 王利2(), 聂小军1()   

  1. 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
  • 收稿日期:2023-07-12 接受日期:2023-09-18 出版日期:2024-05-01 发布日期:2024-05-09
  • 通信作者:
    王利,E-mail:
    聂小军,E-mail:
  • 联系方式: 张颖,E-mail:yingz99040001@gmail.com。
  • 基金资助:
    国家自然科学基金(U22A20457); 国家重点研发计划(2021YFD1900190)

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

ZHANG Ying1(), SHI TingRui1, CAO Rui1, PAN WenQiu1, SONG WeiNing1, WANG Li2(), NIE XiaoJun1()   

  1. 1 College of Agronomy, Northwest A&F University/State Key Laboratory for Crop Stress Resistance and High-Efficiency Production, Yangling 712100, Shaanxi
    2 Institute of Agricultural Resources and Environment, Shandong Academy of Agricultural Sciences/State Key Laboratory of Nutrient Use and Management, Ji’nan 250100
  • Received:2023-07-12 Accepted:2023-09-18 Published:2024-05-01 Online:2024-05-09

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】共检测到102个与苗期抗旱性显著关联的位点,筛选出TraesCS5B02G053500TraesCS6A02G048600 2个关键候选基因,TraesCS6A02G048600的AX-86174509位点是潜在的抗旱性功能位点。

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

Abstract:

【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 values based on these four traits, with the phenotypic variation explained value (PVE) from 1.07% to 38.70%, of which 60 loci were associated with above-ground fresh weight, 1 locus associated with underground fresh weight, 36 loci associated with biomass and the remaining 5 loci associated with root-shoot ratio. Then, 31 candidate genes were predicated based on genomic annotation information and LD block. Combined with the expression patterns of them in roots and other tissues, 4 candidates displaying differential expression between CK and drought conditions were obtained. Finally, the expression levels of these 4 candidates were further verified by qRT-PCR method with the most drought- tolerant accession IR214 and the most drought-sensitive accession IR36 as materials to obtain two key candidates associating with drought tolerance. Additionally, their haplotype effects were investigated. It was found that the different genotypes of AX-86174509 locus in TraesCS6A02G048600 gene showed significant differences in drought tolerance, which might be considered as a causal locus.【Conclusion】Totally, 102 loci and 2 key candidate genes (TraesCS5B02G053500 and TraesCS6A02G048600) underlying drought tolerance at seedling stage were detected in ICARDA-introduced wheat, and AX-86174509 in TraesCS6A02G048600 was a potential functional locus.

Key words: wheat, drought stress, 660K SNP array, genome-wide association analysis, candidate genes