AUTHOR=Liu Hong , Han Guohao , Gu Tiantian , Jin Yuli , Shi Zhipeng , Xing Lixian , Yan Hanwen , Wang Jing , Hao Chenyang , Zhao Meicheng , An Diaoguo 

TITLE=Identification of the major QTL QPm.cas-7D for adult plant resistance to wheat powdery mildew

JOURNAL=Frontiers in Plant Science

VOLUME=13

YEAR=2022

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2022.1042399

DOI=10.3389/fpls.2022.1042399

ISSN=1664-462X

ABSTRACT=<p>Developing effective and durable host plant resistance is crucial for controlling powdery mildew, a devastating disease caused by <italic>Blumeria graminis</italic> f. sp. <italic>tritici</italic> (<italic>Bgt</italic>). In the present study, we dissected the genetic basis of the adult plant resistance to powdery mildew using a recombinant inbred line (RIL) composed of 176 F<sub>9</sub> RILs population derived from a cross between PuBing 3228 (P3228) and susceptible cultivar Gao 8901. P3228 exhibits stable adult-plant resistance to powdery mildew in the field over consecutive years. We identified two QTLs on chromosomes 7DS (<italic>QPm.cas-7D</italic>) and 1AL (<italic>QPm.cas-1A</italic>) contributed by P3228, and one QTL on 3DS (<italic>QPm.cas-3D</italic>) contributed by Gao 8901, which could explain 65.44%, 3.45%, and 2.18% of the phenotypic variances, respectively. By analyzing the annotated genes in the 1.168 Mb physical interval of the major QTL <italic>QPm.cas-7D</italic>, we locked a previously cloned adult-plant resistance gene <italic>Pm38</italic> that was most probably the candidate gene of <italic>QPm.cas-7D.</italic> Sequence alignment analysis revealed that the candidate gene of <italic>QPm.cas-7D</italic> in P3228 was identical to the reported <italic>Pm38</italic> sequence. Two haplotypes <italic>QPm-7D-R</italic> and <italic>QPm-7D-S</italic> were identified in the whole <italic>Pm38</italic> genomic regions between P3228 and Gao 8901. To apply <italic>QPm.cas-7D</italic> in wheat breeding, we developed a kompetitive allele-specific PCR (KASP) marker <italic>Kasp5249</italic> that is closely linked with these haplotypes. It is worth mentioning that the <italic>QPm-7D-R</italic> haplotype significantly decreased TKW and underwent negative selection for higher yields in China wheat breeding. In this study, we identified a major QTL <italic>QPm.cas-7D</italic> and revealed the relationship between its resistance and yield, which could be beneficial for further applications in wheat disease resistance and high-yield breeding.</p>