Journal Article

Multi-environment QTL studies suggest a role for cysteine-rich protein kinase genes in quantitative resistance to blackleg disease in Brassica napus

Yu, Fengqun, Lydiate, Derek J., Borhan, M. Hossein, Wratten, Neil, Barbulescu, Denise M., Larkan, Nicholas J., Raman, Rosy, Rimmer, S. Roger, Salisbury, Philip A., Robinson, Stephen J., Burton, Wayne, Luckett, David J., Raman, Harsh

2016

Overview

Background Resistance to the blackleg disease of Brassica napus (canola/oilseed rape), caused by the hemibiotrophic fungal pathogen Leptosphaeria maculans , is determined by both race-specific resistance ( R ) genes and quantitative resistance loci (QTL), or adult-plant resistance (APR). While the introgression of R genes into breeding material is relatively simple, QTL are often detected sporadically, making them harder to capture in breeding programs. For the effective deployment of APR in crop varieties, resistance QTL need to have a reliable influence on phenotype in multiple environments and be well defined genetically to enable marker-assisted selection (MAS). Results Doubled-haploid populations produced from the susceptible B. napus variety Topas and APR varieties AG-Castle and AV-Sapphire were analysed for resistance to blackleg in two locations over 3 and 4 years, respectively. Three stable QTL were detected in each population, with two loci appearing to be common to both APR varieties. Physical delineation of three QTL regions was sufficient to identify candidate defense-related genes, including a cluster of cysteine-rich receptor-like kinases contained within a 49 gene QTL interval on chromosome A01. Individual L. maculans isolates were used to define the physical intervals for the race-specific R genes Rlm3 and Rlm4 and to identify QTL common to both field studies and the cotyledon resistance response. Conclusion Through multi-environment QTL analysis we have identified and delineated four significant and stable QTL suitable for MAS of quantitative blackleg resistance in B. napus , and identified candidate genes which potentially play a role in quantitative defense responses to L. maculans .

• Publisher: BioMed Central,BioMed Central Ltd
• Subject: Agriculture / Ascomycota - physiology / Bacterial diseases of plants / Biomedical and Life Sciences / Brassica napus / Brassica napus - genetics / Brassica napus - immunology / Brassica napus - microbiology / canola / Chromosome Mapping / Chromosomes, Plant - genetics / cotyledons / cultivars / Diseases and pests / doubled haploids / fungi / genes / Genetic aspects / Identification and classification / introgression / Life Sciences / loci / marker-assisted selection / pathogens / Phenotype / phosphotransferases (kinases) / Plant Diseases - genetics / Plant Diseases - immunology / Plant Diseases - microbiology / Plant Sciences / Plant-biotic interactions / Plenodomus lingam / Properties / Protein kinases / Protein Kinases - genetics / Protein Kinases - metabolism / Quantitative Trait Loci / Rape (Plant) / Research Article / Tree Biology