AUTHOR=Jin Yuli , Gu Tiantian , Li Xiuquan , Liu Hong , Han Guohao , Shi Zhipeng , Zhou Yilin , Fan Jieru , Wang Jing , Liu Wei , Zhao He , An Diaoguo 

TITLE=Characterization of a new splicing variant of powdery mildew resistance gene Pm4 in synthetic hexaploid wheat YAV249

JOURNAL=Frontiers in Plant Science

VOLUME=13

YEAR=2022

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2022.1048252

DOI=10.3389/fpls.2022.1048252

ISSN=1664-462X

ABSTRACT=<p>Powdery mildew, caused by <italic>Blumeria graminis</italic> f. sp. <italic>tritici</italic> (<italic>Bgt</italic>), is a destructive fungal disease of wheat throughout the world. Utilization of effective powdery mildew resistance genes and cultivars is considered as the most economic, efficient, and environmental-friendly method to control this disease. Synthetic hexaploid wheat (SHW), which was developed through hybridization of diploid <italic>Aegilops</italic> and tetraploid wheat, is a valuable genetic resource for resistance to powdery mildew. SHW line YAV249 showed high levels of resistance to powdery mildew at both the seedling and adult stages. Genetic analysis indicated that the resistance was controlled by a single dominant gene, temporarily designated <italic>PmYAV</italic>. Bulked segregant analysis with wheat 660K single nucleotide polymorphism (SNP) array scanning and marker analysis showed that <italic>PmYAV</italic> was located on chromosome 2AL and flanked by markers <italic>Xgdm93</italic> and <italic>Xwgrc763</italic>, respectively, with genetic distances of 0.8 cM and 1.2 cM corresponding to a physic interval of 1.89 Mb on the Chinese Spring reference genome sequence v1.0. Sequence alignment analysis demonstrated that the sequence of <italic>PmYAV</italic> was consistent with that of <italic>Pm4a</italic> but generated an extra splicing event. When inoculated with different <italic>Bgt</italic> isolates, <italic>PmYAV</italic> showed a significantly different spectrum from <italic>Pm4a</italic>, hence it might be a new resistant resource for improvement of powdery mildew resistance. The flanked markers GDM93 and WGRC763, and the co-segregated markers BCD1231 and JS717/JS718 were confirmed to be easily performed in marker-assisted selection (MAS) of <italic>PmYAV</italic>. Using MAS strategy, <italic>PmYAV</italic> was transferred into the commercial cultivar Kenong 199 (KN199) and a wheat line YK13 was derived at generation BC<sub>3</sub>F<sub>3</sub> from the population of YAV249/4*KN199 due to its excellent agronomic traits and resistance to powdery mildew. In conclusion, an alternative splicing variant of <italic>Pm4</italic> was identified in this study, which informed the regulation of <italic>Pm4</italic> gene function.</p>