title: Multi-environment QTL studies suggest a role for cysteine-rich protein kinase genes in quantitative resistance to blackleg disease in Brassica napus.
abstract: 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).
  
  
  
  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.
  
  
  
  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.
authors.affiliation: Saskatoon Research Centre, Agriculture and Agri-Food Canada, Saskatoon, SK, S7N 0X2, Canada.|Armatus Genetics Inc, Saskatoon, SK, S7W 0C9, Canada.
authors.forename: Nicholas J
authors.initials: NJ
authors.lastname: Larkan
authors.affiliation: Graham Centre for Agricultural Innovation (an alliance between Charles Sturt University and NSW Department of Primary Industries), Wagga Wagga Agricultural Institute, Wagga Wagga, NSW 2650, Australia.
authors.forename: Harsh
authors.initials: H
authors.lastname: Raman
authors.affiliation: Saskatoon Research Centre, Agriculture and Agri-Food Canada, Saskatoon, SK, S7N 0X2, Canada.
authors.forename: Derek J
authors.initials: DJ
authors.lastname: Lydiate
authors.affiliation: Saskatoon Research Centre, Agriculture and Agri-Food Canada, Saskatoon, SK, S7N 0X2, Canada.
authors.forename: Stephen J
authors.initials: SJ
authors.lastname: Robinson
authors.affiliation: Saskatoon Research Centre, Agriculture and Agri-Food Canada, Saskatoon, SK, S7N 0X2, Canada.
authors.forename: Fengqun
authors.initials: F
authors.lastname: Yu
authors.affiliation: Department of Economic Development, Jobs, Transport and Resources, Grains Innovation Park, Horsham, VIC, 3400, Australia.
authors.forename: Denise M
authors.initials: DM
authors.lastname: Barbulescu
authors.affiliation: Graham Centre for Agricultural Innovation (an alliance between Charles Sturt University and NSW Department of Primary Industries), Wagga Wagga Agricultural Institute, Wagga Wagga, NSW 2650, Australia.
authors.forename: Rosy
authors.initials: R
authors.lastname: Raman
authors.affiliation: Graham Centre for Agricultural Innovation (an alliance between Charles Sturt University and NSW Department of Primary Industries), Wagga Wagga Agricultural Institute, Wagga Wagga, NSW 2650, Australia.
authors.forename: David J
authors.initials: DJ
authors.lastname: Luckett
authors.affiliation: Department of Economic Development, Jobs, Transport and Resources, Grains Innovation Park, Horsham, VIC, 3400, Australia.|Seednet Australia, Golf Course Road, Horsham, VIC, 3402, Australia.
authors.forename: Wayne
authors.initials: W
authors.lastname: Burton
authors.affiliation: Graham Centre for Agricultural Innovation (an alliance between Charles Sturt University and NSW Department of Primary Industries), Wagga Wagga Agricultural Institute, Wagga Wagga, NSW 2650, Australia.
authors.forename: Neil
authors.initials: N
authors.lastname: Wratten
authors.affiliation: Department of Economic Development, Jobs, Transport and Resources, Centre for AgriBioscience, La Trobe University, Bundoora, VIC, 3083, Australia.|Faculty of Veterinary and Agricultural Sciences, University of Melbourne, Melbourne, VIC, 3010, Australia.
authors.forename: Philip A
authors.initials: PA
authors.lastname: Salisbury
authors.affiliation: Saskatoon Research Centre, Agriculture and Agri-Food Canada, Saskatoon, SK, S7N 0X2, Canada.
authors.forename: S Roger
authors.initials: SR
authors.lastname: Rimmer
authors.affiliation: Saskatoon Research Centre, Agriculture and Agri-Food Canada, Saskatoon, SK, S7N 0X2, Canada. Hossein.Borhan@agr.gc.ca.
authors.forename: M Hossein
authors.initials: MH
authors.lastname: Borhan
mesh_terms: D001203:Ascomycota / Q000502:physiology*; D029688:Brassica napus / Q000235:genetics* / Q000276:immunology / Q000382:microbiology; D002874:Chromosome Mapping; D032461:Chromosomes, Plant / Q000235:genetics; D010641:Phenotype; D010935:Plant Diseases / Q000235:genetics* / Q000276:immunology / Q000382:microbiology; D011494:Protein Kinases / Q000235:genetics* / Q000378:metabolism; D040641:Quantitative Trait Loci
chemical_list: D011494:Protein Kinases
keywords: Blackleg; Brassica napus; CRK; Chitin; Leptosphaeria maculans; Quantitative resistance