AUTHOR=Wang Jiaojiao , Xu Hongxing , Qie Yanmin , Han Ran , Sun Xiaohui , Zhao Ya , Xiao Bei , Qian Zejun , Huang Xiaomei , Liu Ruishan , Zhang Jiadong , Liu Cheng , Jin Yuli , Ma Pengtao 

TITLE=Evaluation and identification of powdery mildew-resistant genes in 137 wheat relatives

JOURNAL=Frontiers in Genetics

VOLUME=15

YEAR=2024

URL=https://www.frontiersin.org/journals/genetics/articles/10.3389/fgene.2024.1342239

DOI=10.3389/fgene.2024.1342239

ISSN=1664-8021

ABSTRACT=<p>Powdery mildew is one of the most severe diseases affecting wheat yield and quality and is caused by <italic>Blumeria graminis</italic> f. sp. <italic>tritici</italic> (<italic>Bgt</italic>). Host resistance is the preferred strategy to prevent this disease. However, the narrow genetic basis of common wheat has increased the demand for diversified germplasm resources against powdery mildew. Wheat relatives, especially the secondary gene pool of common wheat, are important gene donors in the genetic improvement of common wheat because of its abundant genetic variation and close kinship with wheat. In this study, a series of 137 wheat relatives, including 53 <italic>Triticum monococcum</italic> L. (2n = 2x = 14, AA), 6 <italic>T. urartu Thumanjan ex</italic> Gandilyan (2n = 2x = 14, AA), 9 <italic>T. timopheevii</italic> Zhuk. (2n = 4x = 28, AAGG), 66 <italic>T. aestivum</italic> subsp<italic>. spelta</italic> (2n = 6x = 42, AABBDD), and 3 <italic>Aegilops speltoides</italic> (2n = 2x = 14, SS) were systematically evaluated for their powdery mildew resistance and composition of <italic>Pm</italic> genes. Out of 137 (60.58%) accessions, 83 were resistant to <italic>Bgt</italic> isolate E09 at the seedling stage, and 116 of 137 (84.67%) wheat relatives were resistant to the mixture of <italic>Bgt</italic> isolates at the adult stage. This indicates that these accessions show a high level of resistance to powdery mildew. Some 31 markers for 23 known <italic>Pm</italic> genes were used to test these 137 accessions, and, in the results, only <italic>Pm2</italic>, <italic>Pm4</italic>, <italic>Pm6</italic>, <italic>Pm58</italic>, and <italic>Pm68</italic> were detected. Among them, three <italic>Pm4</italic> alleles (<italic>Pm4a</italic>, <italic>Pm4b</italic>, and <italic>Pm4f</italic>) were identified in 4 <italic>T</italic>. subsp<italic>. spelta</italic> accessions. q-RT PCR further confirmed that <italic>Pm4</italic> alleles played a role in disease resistance in these four accessions. The phylogenetic tree showed that the kinship of <italic>Pm4</italic> was close to <italic>Pm24</italic> and <italic>Sr62</italic>. This study not only provides reference information and valuable germplasm resources for breeding new wheat varieties with disease resistance but also lays a foundation for enriching the genetic basis of wheat resistance to powdery mildew.</p>