小麦苗期铅耐受性的全基因组关联分析

目的]随着工业化的推进,重金属尤其是铅对耕地的污染已成为世界性问题.小麦作为主要粮食作物,其健康生产对保障粮食安全意义重大,筛选铅耐受性强和铅低积累小麦品种、挖掘相关调控基因或QTL区间,为耐铅种质创新和揭示小麦铅耐受性遗传机制奠定基础.方法]采用140 mg·kg-1的硝酸铅溶液对102份小麦品种(系)进行苗期胁...

Genome-Wide Association Analysis of Lead Tolerance in Wheat at Seedling Stage

【Objective】With the advancement of industrialization, the pollution of arable land by heavy metals, especially lead, has become a worldwide problem. Wheat is an important food crop, and its safe cultivation is critical to maintaining food security. Screening wheat varieties with strong tolerance to lead, low lead accumulation and mining relevant regulatory genes or QTL regions would lay foundation for further elucidating the genetic mechanism of lead tolerance in wheat. 【Method】The tolerance to lead of 102 wheat varieties (advanced lines) were evaluated with a 140 mg·kg^-1 lead nitrate solution at the seedling stage, by the weighted membership function value (D Value) of the lead tolerance coefficients of maximum root length, root biomass and growth rate under three replicates, combining with the 335 438 high-quality SNPs (single nucleotide polymorphism)markers by wheat 660K SNP chip, a genome-wide association study (GWAS) for lead tolerance in wheat was conducted, to mine the candidate genes for lead tolerance in wheat. 【Result】The lead among between wheat varieties (advanced lines) under different replicates showed rich variation, with the coefficient of variation of 44.8%-46.2%, and the correlation coefficient was between 0.87-0.97 (P<0.001). It was found that varieties with strong lead tolerance showed low lead accumulation characteristics. The genotyping results showed that the SNP polymorphic information content (PIC) was 0.28-0.32, the population structure analysis showed that these wheat materials could be divided into 7 subgroups; a total of 20 SNPs and 8 key chromosomal segments that were significantly associated with lead tolerance in wheat (P≤0.001) were detected by two GWAS methods respectively distributed on chromosomes 1B, 2A, 2D, 3A, 3B, 5A, and 7A. A single locus explains 15.33%-19.75% of the phenotypic variation, and 10 and 8 key chromosomal segments were detected in two and more environments. Analysis of candidate genes for significant and stable association sites and intervals revealed that the functions of the candidate genes were mainly related to transmembrane transport, protein modification and oxidative stress response, including 7 genes related to transporters, including TraesCS1B02G433800, TraesCS7A02G118800, TraesCS7A02G117900 etc. Two genes involved in ubiquitination and deubiquitination (TraesCS2A02G550900 and TraesCS7A02G477300), three genes encoding transmembrane proteins (TraesCS2D02G570500, TraesCS3B02G039900 and TraesCS3B02G466000), one gene related to peroxidase (TraesCS7A02G474200). 【Conclusion】Seven wheat materials with strong lead tolerance were screened, 20 SNPs in 8 candidate regions significantly related to lead tolerance in wheat were detected, and 13 candidate genes related to lead tolerance in wheat were finally screened.