The gene encoding flavonol synthase contributes to lesion mimic in wheat
Tingting Dong,
Hongchun Xiong,
Huijun Guo,
Yongdun Xie,
Linshu Zhao,
Jiayu Gu,
Huiyuan Li,
Shirong Zhao,
Yuping Ding,
Xiyun Song,
Luxiang Liu
Affiliations
Tingting Dong
College of Life Sciences, Key Laboratory of Major Crop Germplasm Innovation and Application in Qingdao, Qingdao Agricultural University, Qingdao 266109, Shandong, China; State Key Laboratory of Crop Gene Resources and Breeding/National Engineering Laboratory of Crop Molecular Breeding/CAEA Research and Development Centre on Nuclear Technology Applications for Irradiation Mutation Breeding, Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing 100081, China
Hongchun Xiong
State Key Laboratory of Crop Gene Resources and Breeding/National Engineering Laboratory of Crop Molecular Breeding/CAEA Research and Development Centre on Nuclear Technology Applications for Irradiation Mutation Breeding, Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing 100081, China
Huijun Guo
State Key Laboratory of Crop Gene Resources and Breeding/National Engineering Laboratory of Crop Molecular Breeding/CAEA Research and Development Centre on Nuclear Technology Applications for Irradiation Mutation Breeding, Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing 100081, China
Yongdun Xie
State Key Laboratory of Crop Gene Resources and Breeding/National Engineering Laboratory of Crop Molecular Breeding/CAEA Research and Development Centre on Nuclear Technology Applications for Irradiation Mutation Breeding, Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing 100081, China
Linshu Zhao
State Key Laboratory of Crop Gene Resources and Breeding/National Engineering Laboratory of Crop Molecular Breeding/CAEA Research and Development Centre on Nuclear Technology Applications for Irradiation Mutation Breeding, Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing 100081, China
Jiayu Gu
State Key Laboratory of Crop Gene Resources and Breeding/National Engineering Laboratory of Crop Molecular Breeding/CAEA Research and Development Centre on Nuclear Technology Applications for Irradiation Mutation Breeding, Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing 100081, China
Huiyuan Li
State Key Laboratory of Crop Gene Resources and Breeding/National Engineering Laboratory of Crop Molecular Breeding/CAEA Research and Development Centre on Nuclear Technology Applications for Irradiation Mutation Breeding, Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing 100081, China
Shirong Zhao
State Key Laboratory of Crop Gene Resources and Breeding/National Engineering Laboratory of Crop Molecular Breeding/CAEA Research and Development Centre on Nuclear Technology Applications for Irradiation Mutation Breeding, Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing 100081, China
Yuping Ding
State Key Laboratory of Crop Gene Resources and Breeding/National Engineering Laboratory of Crop Molecular Breeding/CAEA Research and Development Centre on Nuclear Technology Applications for Irradiation Mutation Breeding, Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing 100081, China
Xiyun Song
College of Life Sciences, Key Laboratory of Major Crop Germplasm Innovation and Application in Qingdao, Qingdao Agricultural University, Qingdao 266109, Shandong, China
Luxiang Liu
State Key Laboratory of Crop Gene Resources and Breeding/National Engineering Laboratory of Crop Molecular Breeding/CAEA Research and Development Centre on Nuclear Technology Applications for Irradiation Mutation Breeding, Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing 100081, China; Corresponding author.
Lesion mimic often exhibits leaf disease-like symptoms even in the absence of pathogen infection, and is characterized by a hypersensitive-response (HR) that closely linked to plant disease resistance. Despite this, only a few lesion mimic genes have been identified in wheat. In this investigation, a lesion mimic wheat mutant named je0297 was discovered, showing no alteration in yield components when compared to the wild type (WT). Segregation ratio analysis of the F2 individuals resulting from the cross between the WT and the mutant revealed that the lesion mimic was governed by a single recessive gene in je0297. Using Bulked segregant analysis (BSA) and exome capture sequencing, we mapped the lesion mimic gene designated as lm6 to chromosome 6BL. Further gene fine mapping using 3315 F2 individuals delimited the lm6 within a 1.18 Mb region. Within this region, we identified 16 high-confidence genes, with only two displaying mutations in je0297. Notably, one of the two genes, responsible for encoding flavonol synthase, exhibited altered expression levels. Subsequent phenotype analysis of TILLING mutants confirmed that the gene encoding flavonol synthase was indeed the causal gene for lm6. Transcriptome sequencing analysis revealed that the DEGs between the WT and mutant were significantly enriched in KEGG pathways related to flavonoid biosynthesis, including flavone and flavonol biosynthesis, isoflavonoid biosynthesis, and flavonoid biosynthesis pathways. Furthermore, more than 30 pathogen infection-related (PR) genes exhibited upregulation in the mutant. Corresponding to this expression pattern, the flavonoid content in je0297 showed a significant decrease in the 4th leaf, accompanied by a notable accumulation of reactive oxygen, which likely contributed to the development of lesion mimic in the mutant. This investigation enhances our comprehension of cell death signaling pathways and provides a valuable gene resource for the breeding of disease-resistant wheat.
