Characterization and fine mapping of a lesion mimic mutant (Lm5) with enhanced stripe rust and powdery mildew resistance in bread wheat (Triticum aestivum L.)

https://link.springer.com/article/10.1007/s00122-021-03973-1

Cong Li,Hang Liu,Jian Wang,Qi Pan,Yue Wang,Kunyan Wu,Peiying Jia,Yang Mu,Huaping Tang,Qiang Xu,Qiantao Jiang,Yaxi Liu,Pengfei Qi,Xiaojun Zhang,Lin Huang,Guoyue Chen,Jirui Wang,Yuming Wei,Youliang Zheng,Lulu Gou,Qifu Yao,Xiujin Lan&Jian Ma

Abstract

Lesion mimic mutants are ideal for studying disease resistance and programmed cell death photosynthesis in plants to improve crop yield. In this study, a novel light intensity-dependent lesion mimic mutant (MC21) was obtained from the wheat variety Chuannong16 (CN16) by ethyl methane sulfonate treatment. The mutant initially developed tiny lesion spots on the basal part of the leaves, which then gradually proceeded down to leaf sheaths, stems, shells, and awns at the flowering stage. The major agronomic traits were significantly altered in the mutant compared to that in the wild-type CN16. Furthermore, the mutant exhibited a lesion phenotype with degenerated chloroplast structure, decreased chlorophyll content, increased level of reactive oxygen species, and increased resistance to stripe rust and powdery mildew. Genetic analysis indicated that the lesion phenotype was controlled by a novel single semi-dominant nuclear gene. The target gene was mapped on chromosome arm 2AL located between Kompetitive Allele Specific PCR (KASP) markers,KASP-4211andKASP-5353, and tentatively termed aslesion mimic 5(Lm5). The fine mapping suggested thatLm5was located in a 1.28 Mbp interval between markersKASP-5825andKASP-9366; 17 high-confidence candidate genes were included in this genomic region. This study provides an important foundational step for further cloning ofLm5using a map-based approach.