Xinyue Shu1,2,3, Aijun Wang1,3, Bo Jiang4, Yuqi Jiang1,2,3, Xing Xiang1,2,3, Xiaoqun Yi1, Shuangcheng Li2, Qiming Deng2, Shiquan Wang2, Jun Zhu2, Yueyang Liang2, Huainian Liu2, Ting Zou2, Lingxia Wang2, Ping Li2, Aiping Zheng5,6. 1. College of Agronomy, Sichuan Agricultural University, Chengdu, China. 2. Rice Research Institute of Sichuan Agricultural University, Chengdu, China. 3. State Key Laboratory of Crop Gene Exploration and Utilization in Southwest China, Chengdu, China. 4. College of Life Science and Technology, Yangtz Normal University, Chongqing, China. 5. College of Agronomy, Sichuan Agricultural University, Chengdu, China. aipingzh@163.com. 6. State Key Laboratory of Crop Gene Exploration and Utilization in Southwest China, Chengdu, China. aipingzh@163.com.
Abstract
BACKGROUND: Rice (Oryza sativa) bacterial leaf blight (BLB), caused by the hemibiotrophic Xanthomonas oryzae pv. oryzae (Xoo), is one of the most devastating diseases affecting the production of rice worldwide. The development and use of resistant rice varieties or genes is currently the most effective strategy to control BLB. RESULTS: Here, we used 259 rice accessions, which are genotyped with 2 888 332 high-confidence single nucleotide polymorphisms (SNPs). Combining resistance variation data of 259 rice lines for two Xoo races observed in 2 years, we conducted a genome-wide association study (GWAS) to identify quantitative trait loci (QTL) conferring plant resistance against BLB. The expression levels of genes, which contains in GWAS results were also identified between the resistant and susceptible rice lines by transcriptome analysis at four time points after pathogen inoculation. From that 109 candidate resistance genes showing significant differential expression between resistant and susceptible rice lines were uncovered. Furthermore, the haplotype block structure analysis predicted 58 candidate genes for BLB resistance based on Chr. 7_707158 with a minimum P-value (-log 10 P = 9.72). Among them, two NLR protein-encoding genes, LOC_Os07g02560 and LOC_Os07g02570, exhibited significantly high expression in the resistant line, but had low expression in the susceptible line of rice. CONCLUSIONS: Together, our results reveal novel BLB resistance gene resources, and provide important genetic basis for BLB resistance breeding of rice crops.
BACKGROUND:Rice (Oryza sativa) bacterial leaf blight (BLB), caused by the hemibiotrophic Xanthomonas oryzae pv. oryzae (Xoo), is one of the most devastating diseases affecting the production of rice worldwide. The development and use of resistant rice varieties or genes is currently the most effective strategy to control BLB. RESULTS: Here, we used 259 rice accessions, which are genotyped with 2 888 332 high-confidence single nucleotide polymorphisms (SNPs). Combining resistance variation data of 259 rice lines for two Xoo races observed in 2 years, we conducted a genome-wide association study (GWAS) to identify quantitative trait loci (QTL) conferring plant resistance against BLB. The expression levels of genes, which contains in GWAS results were also identified between the resistant and susceptible rice lines by transcriptome analysis at four time points after pathogen inoculation. From that 109 candidate resistance genes showing significant differential expression between resistant and susceptible rice lines were uncovered. Furthermore, the haplotype block structure analysis predicted 58 candidate genes for BLB resistance based on Chr. 7_707158 with a minimum P-value (-log 10 P = 9.72). Among them, two NLR protein-encoding genes, LOC_Os07g02560 and LOC_Os07g02570, exhibited significantly high expression in the resistant line, but had low expression in the susceptible line of rice. CONCLUSIONS: Together, our results reveal novel BLB resistance gene resources, and provide important genetic basis for BLB resistance breeding of rice crops.