Germplasm Development, ARC-Small Grain, Bethlehem, Free State, South Africa.
Department of Botany and Plant Biotechnology, University of Johannesburg, Johannesburg, Gauteng, South Africa.
PLoS One. 2020 Dec 28;15(12):e0244455. doi: 10.1371/journal.pone.0244455. eCollection 2020.
Russian wheat aphid (RWA; Diuraphis noxia Kurdjumov) resistance on the 1D chromosome of wheat has been the subject of intensive research. Conversely, the deployment of the Dn4 derived RWA resistant varieties diminished in recent years due to the overcoming of the resistance it imparts in the United States of America. However, this resistance has not been deployed in South Africa despite reports that Dn4 containing genotypes exhibited varying levels of resistance against the South African RWA biotypes. It is possible that there may be certain genetic differences within breeding lines or cultivars that influence the expression of resistance. The aim of this study was to identify single nucleotide polymorphism (SNP) markers associated with resistance to South African RWA biotypes. A panel of thirty-two wheat lines were phenotyped for RWA resistance using four South African RWA biotypes and a total of 181 samples were genotyped using the Illumina 9K SNP wheat chip. A genome wide association study using 7598 polymorphic SNPs showed that the population was clustered into two distinct subpopulations. Twenty-seven marker trait associations (MTA) were identified with an average linkage disequilibrium of 0.38 at 10 Mbp. Four of these markers were highly significant and three correlated with previously reported quantitative trait loci linked to RWA resistance in wheat. Twenty putative genes were annotated using the IWGSC RefSeq, three of which are linked to plant defence responses. This study identified novel chromosomal regions that contribute to RWA resistance and contributes to unravelling the complex genetics that control RWA resistance in wheat.
俄罗斯小麦蚜虫（RWA；Diuraphis noxia Kurdjumov）对小麦 1D 染色体的抗性一直是研究的重点。相反，近年来由于美国克服了它赋予的抗性，Dn4 衍生的 RWA 抗性品种的部署有所减少。然而，尽管有报道称含有 Dn4 的基因型对南非 RWA 生物型表现出不同程度的抗性，但这种抗性并未在南非部署。可能是由于某些遗传差异，影响了抗性的表达。本研究旨在鉴定与南非 RWA 生物型抗性相关的单核苷酸多态性（SNP）标记。使用四个南非 RWA 生物型对 32 个小麦品系进行了 RWA 抗性表型鉴定，共对 181 个样本进行了 Illumina 9K SNP 小麦芯片的基因型鉴定。使用 7598 个多态性 SNP 的全基因组关联研究表明，该群体分为两个不同的亚群。鉴定出 27 个标记-性状关联（MTA），平均连锁不平衡为 10 Mbp 处的 0.38。其中 4 个标记高度显著，3 个与先前报道的与小麦中 RWA 抗性相关的数量性状位点相关。使用 IWGSC RefSeq 对 20 个假定基因进行注释，其中 3 个与植物防御反应有关。这项研究鉴定了新的染色体区域，这些区域有助于 RWA 抗性，并有助于揭示控制小麦中 RWA 抗性的复杂遗传。
