Identification and characterization of candidate Rlm4 blackleg resistance genes 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 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 B. napus for its most devastating fungal pathogen, Leptosphaeria maculans (blackleg fungus). These two species are locked in an evolutionary arms race whereby a gene-for-gene interaction confers either resistance or susceptibility in the plant depending on the genotype of the plant and pathogen. Preliminary analysis of the complete genome sequence of Brassica rapa, the diploid progenitor of B. napus, identified numerous candidate genes with disease resistance characteristics, several of which were clustered around a region syntenic with a major locus (Rlm4) for blackleg resistance on A7 of B. napus. Molecular analyses of the candidate genes using B. napus NGS data are presented, and the difficulties associated with identifying functional gene copies within the highly duplicated Brassica genome are discussed.
Centre for Integrative Legume Research and School of Agriculture and Food Sciences, University of Queensland, Brisbane, Qld, Australia.
Reece
R
Tollenaere
Alice
A
Hayward
Jessica
J
Dalton-Morgan
Emma
E
Campbell
Joanne R M
JR
Lee
Michal T
MT
Lorenc
Sahana
S
Manoli
Jiri
J
Stiller
Rosy
R
Raman
Harsh
H
Raman
David
D
Edwards
Jacqueline
J
Batley
D001203:Ascomycota / Q000502:physiology*; D029688:Brassica napus / Q000235:genetics* / Q000276:immunology; D060467:Disease Resistance; D017343:Genes, Plant; D054884:Host-Pathogen Interactions / Q000235:genetics*; D010935:Plant Diseases / Q000276:immunology; D040641:Quantitative Trait Loci; D017422:Sequence Analysis, DNA