Identification and validation of genes conferring foliar blast resistance in pearl millet using genome wide association mapping strategy

Abstract: Foliar blast (FB), aka leaf spot caused by Magnaporthe grisea, became major threat to cultivation affecting both forage and grain production of pearl millet hybrids, and parental lines. Even though there exists a huge genetic variability against FB, no systematic efforts were undertaken to identify or map new resistance genes. Identifying novel alleles and gene associated with FB resistance will help in resistance breeding. A panel of 250 genotypes was evaluated at seven different environments under natural epiphytic conditions. The disease development, was scored following the 0-9 progressive scale at all the seven environments. SNP genotyping was carried out using genotype-by-sequencing (GBS) approach. A set of 74K SNP genotyping data were used for genome-wide association study (GWAS) to identify genes/alleles for FB resistance. The relative magnitude of each association was represented by the proportion of variation explained (r) by the marker at the threshold -logio p-value >5.00. Forty-six most significant marker trait associations for FB resistance were identified on pseudo molecules 1, 2, 3, 4 and 7. A SNP on Chr 3 was found consistently associated with blast resistance. Analysis of the upstream and downstream window +2 kb of the SNP loci detected 10 putative candidate genes encoding for Fbox-LRR proteins. This is the first report genes associated with Pearl millet-Magnaporthe interaction. The expression studies validated the SNP among the resistant genotypes for which KASP markers were developed. Conference Details: MENDELSYM-Symposium Commemorating Birth Bicentenary of Gregor Johann Mendel, New Delhi, India Publication date: 2022/7/21