Genome-wide Association Study Identifies New Loci for Resistance toLeptosphaeria maculansin Canola.
Key message "We identified both quantitative and quantitative resistance loci toLeptosphaeria maculans, a fungal pathogen, causing blackleg disease in canola. Several genome-wide significant associations were detected at known and new loci for blackleg resistance. We further validated statistically significant associations in four genetic mapping populations, demonstrating that GWAS marker loci are indeed associated with resistance toL. maculans.One of the novel loci identified for the first time,Rlm12, conveys adult plant resistance in canola." Blackleg, caused byLeptosphaeria maculans, is a significant disease which affects the sustainable production of canola (Brassica napus). This study reports a genome-wide association study based on 18,804 polymorphic SNPs to identify loci associated with qualitative and quantitative resistance toL. maculans. Genomic regions delimited with 694 significant SNP markers, that are associated with resistance evaluated using 12 single spore isolates and pathotypes from four canola stubble were identified. Several significant associations were detected at known disease resistance loci including in the vicinity of recently clonedRlm2/LepR3genes, and at new loci on chromosomes A01/C01, A02/C02, A03/C03, A05/C05, A06, A08, and A09. In addition, we validated statistically significant associations on A01, A07, and A10 in four genetic mapping populations, demonstrating that GWAS marker loci are indeed associated with resistance toL. maculans. One of the novel loci identified for the first time,Rlm12, conveys adult plant resistance and mapped within 13.2 kb fromArabidopsis Rgene of TIR-NBS class. We showed that resistance loci are located in the vicinity ofRgenes ofArabidopsis thalianaandBrassica napuson the sequenced genome ofB. napuscv. Darmor-bzh. Significantly associated SNP markers provide a valuable tool to enrich germplasm for favorable alleles in order to improve the level of resistance toL. maculansin canola.
Graham Centre for Agricultural Innovation (an alliance between NSW Department of Primary Industries and Charles Sturt University), Wagga Wagga Agricultural Institute, Wagga Wagga NSW, Australia.
Harsh
H
Raman
Graham Centre for Agricultural Innovation (an alliance between NSW Department of Primary Industries and Charles Sturt University), Wagga Wagga Agricultural Institute, Wagga Wagga NSW, Australia.
Rosy
R
Raman
Graham Centre for Agricultural Innovation (an alliance between NSW Department of Primary Industries and Charles Sturt University), Wagga Wagga Agricultural Institute, Wagga Wagga NSW, Australia.
Neil
N
Coombes
Diversity Array Technology P/L, University of Canberra, Canberra ACT, Australia.
Jie
J
Song
Centre for Bioinformatics and Biometrics, University of Wollongong, Wollongong NSW, Australia.
Simon
S
Diffey
Diversity Array Technology P/L, University of Canberra, Canberra ACT, Australia.
Andrzej
A
Kilian
Graham Centre for Agricultural Innovation (an alliance between NSW Department of Primary Industries and Charles Sturt University), Wagga Wagga Agricultural Institute, Wagga Wagga NSW, Australia.
Kurt
K
Lindbeck
Department of Economic Development, Jobs, Transport and Resources, Horsham VIC, Australia.
Denise M
DM
Barbulescu
School of Plant Biology, University of Western Australia, Crawley WA, Australia.
Jacqueline
J
Batley
School of Plant Biology, University of Western Australia, CrawleyWA, Australia; Institute of Agriculture, University of Western Australia, CrawleyWA, Australia.
David
D
Edwards
Department of Economic Development, Jobs, Transport and Resources, HorshamVIC, Australia; Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, ParkvilleVIC, Australia.
Phil A
PA
Salisbury
Marcroft Grains Pathology, Horsham VIC, Australia.
Steve
S
Marcroft
blackleg; canola; comparative mapping; genome-wide association analysis; linkage analysis; natural variation; race-specific and race non-specific resistance; resistance to L. maculans