Identification and Characterisation of Candidate Genes for Blackleg Resistance in Brassica napus Using Next Generation Sequencing

A thorough understanding of the relationships between plants and pathogens is essential if we are to continue to meet the agricultural needs of the world’s growing population.  The identification of genes underlying important quantitative trait loci (QTL) is extremely challenging in complex genomes such as Brassica napus (canola, oilseed rape or rapeseed).  However, recent advances in next generation sequencing (NGS) enable much quicker identification of candidate genes for traits of interest. Here we demonstrate this with the identification of candidate disease resistance genes from Brassica napus for its most devastating fungal pathogen, Leptosphaeria maculans, the causal agent of blackleg disease. Analysis of the complete genome sequence of the diploid progenitor of B. napus: B. rapa, identified candidate CC-NBS-LRR and TIR-NBS-LRR family genes implicated in disease response, several of which were clustered around a region syntenic with major loci for blackleg resistance in B. napus.  By combining phenotypic data with next genereation sequencing data, cultivar specific reads can be utilised to determine alleles within identified candidate genes that are associated with the trait of interest. Molecular analyses of four of these candidate genes, Rlm1, 2, 3 and 4 using NGS and high throughput SNP genotyping in diverse cultivars, along with initial validation, will be presented.