大豆胞囊线虫主效抗病基因Rhg4(GmSHMT)的CAPS/dCAPS标记开发和利用

大豆胞囊线虫(soybean cyst nematode,SCN)严重危害世界大豆生产,Rhg4(resistance to Heterodera glycines 4)是控制大豆SCN抗性的2个主效位点之一。本研究针对Rhg4(Gm SHMT)上的2个单核苷酸多态性(single nucleotide polymorphisms,SNP)位点开发了快速、经济、简便易行的CAPS(Rhg4-389)和d CAPS标记(Rhg4-1165),并用开发的2个标记鉴定了以大豆胞囊线虫应用核心种质为主的193份代表性抗感种质。结果表明,Rhg4-389和Rhg4-1165位点间存在显著连锁不平衡(P=0.0001,r2=0.87),可形成4种单倍型。Rhg4-389-G/Rhg4-1165-T和Rhg4-389-C/Rhg4-1165-A为优势单倍型,稀有单倍型Rhg4-389-G/Rhg4-1165-A和Rhg4-389-C/Rhg4-1165-T是在中国抗源中新发现的单倍型。结合193份种质对SCN 3号小种抗性鉴定分析发现,Rhg4-389-G和Rhg4-1165-T主要存在于抗病种质,它们形成的单倍型对抗病种质鉴定效率可达94.1%。本研究开发了可用于辅助大豆SCN抗性鉴定且方便育种家利用的CAPS/d CAPS标记,且用其摸清了应用核心种质等重要抗源在Rhg4位点的"本底",为育种家有效利用这些优异抗源提供了重要信息。

Development and Utilization of CAPS/dCAPS Markers Based on the SNPs Lying in Soybean Cyst Nematode Resistant Genes Rhg4

Soybean cyst nematode (SCN, Heterodera glycines Ichinohe) is one of the most destructive diseases which largely suppressed soybean production worldwide. Rhg4 was one of two major resistant loci for SCN. In this study two nonsynonymous SNPs (Rhg4-389-G/C and Rhg4-1165-T/A) in GmSHMT were deduced to confer SCN resistance or susceptibility. One CAPS marker (Rhg4-389) and one dCAPS marker (Rhg4-1165) with the advantages of rapid, economic, simple and easy way to use were developed based on two nonsynonymous SNPs (Rhg4-389-G/C and Rhg4-1165-T/A), respectively. Then, a total of 193 soybean cultivars mainly from SCN-applied-core collection were genotyped by markers Rhg4-389 and Rhg4-1165. Linkage disequilibrium (LD) analysis indicated pairwise of Rhg4-389 and Rhg4-1165 was in significant LD (P-value = 0.0001) with r² of 0.87. Among four haplotypes detected in this panel, Rhg4-389-G/Rhg4-1165-T and Rhg4-389-C/Rhg4-1165-A were predominant; while both Rhg4-389-G/Rhg4-1165-A and Rhg4-389-C/Rhg4-1165-T were rare, which only discovered in the resistant cultivars from China. Rhg4-389-G and Rhg4-1165-T alleles mainly occurred in resistant cultivars, and almost coincided with Rhg4-389-G/Rhg4-1165-T haplotype. Of 101 resistant cultivars with Rhg4-389-G/Rhg4-1165-T haplotype, 94.1% (95) were resistant to SCN. In this study, we not only developed convenient CAPS/dCAPS markers for marker assisted selection (MAS) breeding, but also dissected the genetic architecture of Rhg4 locus among SCN-applied-core collection. Hopefully, this study will provide helpful information for improving the utilization efficiency of resistant resources in soybean breeding.