The Applied Plant Genomics Laboratory, Crop Genomics and Bioinformatics Center and National Key Laboratory of Crop Genetics and Germplasm Enhancement, College of Agricultural Sciences, Nanjing Agricultural University, Nanjing, 210095, Jiangsu, China.
Zhongshan Biological Breeding Laboratory, No.50 Zhongling Street, Nanjing, 210014, Jiangsu, China.
Theor Appl Genet. 2023 May 22;136(6):134. doi: 10.1007/s00122-023-04380-4.
Two loci inhibiting Fhb1 resistance to Fusarium head blight were identified through genome-wide association mapping and validated in biparental populations. Fhb1 confers Fusarium head blight (FHB) resistance by limiting fungal spread within spikes in wheat (type II resistance). However, not all lines with Fhb1 display the expected resistance. To identify genetic factors regulating Fhb1 effect, a genome-wide association study for type II resistance was first performed with 72 Fhb1-carrying lines using the Illumina 90 K iSelect SNP chip. Of 84 significant marker-trait associations detected, more than half were repeatedly detected in at least two environments, with the SNPs distributed in one region on chromosome 5B and one on chromosome 6A. This result was validated in a collection of 111 lines with Fhb1 and 301 lines without Fhb1. We found that these two loci caused significant resistance variations solely among lines with Fhb1 by compromising the resistance. In1, the inhibitory gene on chromosome 5B, was in close linkage with Xwgrb3860 in a recombinant inbred line population derived from Nanda2419 × Wangshuibai and a double haploid (DH) population derived from R-43 (Fhb1 near isogenic line) × Biansui7 (with Fhb1 and In1); and In2, the inhibitory gene on chromosome 6A, was mapped to the Xwgrb4113-Xwgrb4034 interval using a DH population derived from R-43 × PH8901 (with Fhb1 and In2). In1 and In2 are present in all wheat-growing areas worldwide. Their frequencies in China's modern cultivars are high but have significantly decreased in comparison with landraces. These findings are of great significance for FHB resistance breeding using Fhb1.
两个抑制 Fhb1 对赤霉病抗性的基因座通过全基因组关联图谱进行鉴定，并在双亲群体中进行验证。Fhb1 通过限制小麦穗部真菌的扩散（II 型抗性）赋予赤霉病抗性。然而，并非所有具有 Fhb1 的品系都表现出预期的抗性。为了鉴定调节 Fhb1 效应的遗传因素，首次使用 Illumina 90K iSelect SNP 芯片对 72 个携带 Fhb1 的品系进行了 II 型抗性的全基因组关联研究。在检测到的 84 个显著标记-性状关联中，超过一半在至少两个环境中重复检测到，这些 SNP 分布在 5B 染色体上的一个区域和 6A 染色体上的一个区域。在携带 Fhb1 的 111 个品系和不携带 Fhb1 的 301 个品系的集合中验证了这一结果。我们发现，这两个基因座仅在携带 Fhb1 的品系中导致显著的抗性变化，因为它们削弱了抗性。在重组自交系群体 Nanda2419×Wangshuibai 和源自 R-43（带有 Fhb1 和 In1）的双单倍体（DH）群体中，5B 染色体上的抑制基因 In1 与 Xwgrb3860 紧密连锁；在源自 R-43×Biansui7（带有 Fhb1 和 In1）的 DH 群体中，6A 染色体上的抑制基因 In2 被定位到 Xwgrb4113-Xwgrb4034 区间。In1 和 In2 存在于全球所有小麦种植区。它们在中国现代品种中的频率较高，但与地方品种相比显著降低。这些发现对于利用 Fhb1 进行赤霉病抗性育种具有重要意义。
