Correlation between leaf and panicle blast resistance to Magnaporthe oryzae B.C. Couch and genome-wide associations study of panicle blast resistance in rice
2015
Yang Jianyuan
Although caused by the same pathogen Magnaporthe oryzae, the correlation between leaf blast (LB) and panicle blast (PB) resistance on the same rice variety has not been fully studied. The authors established an improved panicle blast inoculation protocol, involving the use of modified cotton wrapping technique and jute sack cages for greenhouse studies, which is undestructive and stable, and enable us to evaluate large number of entries. Data generated from both greenhouse and blast nursery trials from at least three seasons and two locations (IRRI [International Rice Research Institute] and GDAAS [Guangdong Academy of Agricultural Sciences]) robustly established a significant correlation between LB and PB. Pearson correlation value consistently ranged from r = 0.5 to 0.8. Genome wide association studies (GWAS) was also undertaken using the phenotypic data (PB and LB) generated from a subset of 482 lines from the IRRI 2k rice genome project. Single nucleotide polymorphic markers (SNPs) associated LB resistance were detected in three genomic intervals on chromosomes 9, 11 and 12 which carry more than 20 blast resistance genes. Among them, SNPs significantly associated with PB were all located near some known rice resistance genes on chromosomes 9. Some SNPs not associated with known blast genes have been detected suggesting possible new genes conferring resistance to LB and PB.
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