Association Analysis of White Rust Resistance Genes and Studies on Transformation Response of Susceptible Genotypes of Brassica juncea L

Abstract

newlineThe study entitled Association Analysis of White Rust Resistance Genes and Studies on Transformation Response of Susceptible Genotypes of Brassica juncea L. was conducted to analyse the population structure of B. juncea genotypes for white rust resistance and economically important traits; to detect single nucleotide polymorphisms (SNPs) and establish marker-trait association in Brassica juncea for white rust resistance and economically important traits; and to screen the variants for response to Agrobacterium tumifaciens mediated transformation in elite white rust susceptible B. juncea varieties. To accomplish the study a diverse panel of ninety Brassica juncea genotypes was used. Data of the experimental genotypes were recorded for traits such as white rust reaction, grain yield/plant, oil content, erucic acid and glucosinolate content using standard protocols. The germplasm was genotyped by genotype-by-sequencing (GBS) with ddRAD strategy using restriction enzymes Sph1 and Mluc1.Population structure analysis was done using fastSTRUCTURE software. The genome wide associations between SNP identified and trait studied were done using TASSEL (5.2.81) software involving Mixed Linear Model. Agrobacterium mediated genetic transformation was done using hypocotyl and cotyledonary leaf explants from two varieties of Brassica juncea (RSPR 01 and Varuna) by optimizing various factors influencing transformation. Agrobacterium strain LBA4404 containing plasmid pBI121 and reporter gene GUS was used in the study. Genotypes Donskaja IV, Domo and Cutlass showed immune reaction against white rust and could be used as resistant sources for breeding white rust resistant varieties. Genotypes DRMR-2017, J807/1/6 and Vardan for higher grain yield per plant; PGR 12573, EC 287711, Stoke and Jubilejnaja for oil content; Donskaja IV, Volgogradskaja 1891 and PGR 12573 for low erucic acid and Heera for low glucosinolate contents were identified which will be useful for improvement of these traits in new Brassica ju