Lhamo Dhondup, Li Genqiao, Song George, Li Xuehui, Sen Taner Z, Gu Yong-Qiang, Xu Xiangyang, Xu Steven S
USDA-ARS, Crop Improvement and Genetics Research Unit, Western Regional Research Center, Albany, California, USA.
USDA-ARS Peanut and Small Grains Research Unit, Stillwater, Oklahoma, USA.
Plant Genome. 2025 Mar;18(1):e20493. doi: 10.1002/tpg2.20493. Epub 2024 Jul 28.
Powdery mildew, caused by the fungal pathogen Blumeria graminis (DC.) E. O. Speer f. sp. tritici Em. Marchal (Bgt), is a constant threat to global wheat (Triticum aestivum L.) production. Although ∼100 powdery mildew (Pm) resistance genes and alleles have been identified in wheat and its relatives, more is needed to minimize Bgt's fast evolving virulence. In tetraploid wheat (Triticum turgidum L.), wild emmer wheat [T. turgidum ssp. dicoccoides (Körn. ex Asch. & Graebn.) Thell.] accessions from Israel have contributed many Pm resistance genes. However, the diverse genetic reservoirs of cultivated emmer wheat [T. turgidum ssp. dicoccum (Schrank ex Schübl.) Thell.] have not been fully exploited. In the present study, we evaluated a diverse panel of 174 cultivated emmer accessions for their reaction to Bgt isolate OKS(14)-B-3-1 and found that 66% of accessions, particularly those of Ethiopian (30.5%) and Indian (6.3%) origins, exhibited high resistance. To determine the genetic basis of Bgt resistance in the panel, genome-wide association studies were performed using 46,383 single nucleotide polymorphisms (SNPs) from genotype-by-sequencing and 4331 SNPs from the 9K SNP Infinium array. Twenty-five significant SNP markers were identified to be associated with Bgt resistance, of which 21 SNPs are likely novel loci, whereas four possibly represent emmer derived Pm4a, Pm5a, PmG16, and Pm64. Most novel loci exhibited minor effects, whereas three novel loci on chromosome arms 2AS, 3BS, and 5AL had major effect on the phenotypic variance. This study demonstrates cultivated emmer as a rich source of powdery mildew resistance, and the resistant accessions and novel loci found herein can be utilized in wheat breeding programs to enhance Bgt resistance in wheat.
由真菌病原体禾本科布氏白粉菌（Blumeria graminis (DC.) E. O. Speer f. sp. tritici Em. Marchal，简称Bgt）引起的白粉病，一直威胁着全球小麦（Triticum aestivum L.）生产。尽管在小麦及其近缘种中已鉴定出约100个抗白粉病（Pm）基因和等位基因，但仍需要更多基因来尽量减少Bgt快速进化的毒力。在四倍体小麦（Triticum turgidum L.）中，来自以色列的野生二粒小麦（T. turgidum ssp. dicoccoides (Körn. ex Asch. & Graebn.) Thell.）种质贡献了许多Pm抗性基因。然而，栽培二粒小麦（T. turgidum ssp. dicoccum (Schrank ex Schübl.) Thell.）的多种基因库尚未得到充分利用。在本研究中，我们评估了174份栽培二粒小麦种质对Bgt分离株OKS(14)-B-3-1的反应，发现66%的种质，特别是那些来自埃塞俄比亚（30.5%）和印度（6.3%）的种质，表现出高抗性。为了确定该种质群体中抗Bgt的遗传基础，利用通过测序分型获得的46383个单核苷酸多态性（SNP）和9K SNP Infinium芯片上的4331个SNP进行全基因组关联研究。鉴定出25个与抗Bgt相关的显著SNP标记，其中21个SNP可能是新位点，而4个可能代表源自二粒小麦的Pm4a、Pm5a、PmG16和Pm64。大多数新位点表现出较小的效应，而位于染色体臂2AS上的3个新位点、3BS和5AL对表型变异有主要影响。本研究表明栽培二粒小麦是抗白粉病的丰富来源，本文发现的抗性种质和新位点可用于小麦育种计划，以增强小麦对Bgt的抗性。
