Identification of five QTLs for clubroot resistance to three novel pathotypes of Plasmodiophora brassicae in Brassica oleracea through genotyping-by-sequencing

Citation

Karim, M, Fu, F., Dakouri, A., Strelkov, S., Gossen, B., Peng, G., and Yu, F. 2019. Identification of five QTLs for clubroot resistance to three novel pathotypes of Plasmodiophora brassicae in Brassica oleracea through genotyping-by-sequencing. Proc. Plant Canada 2019, pg. 259. PC2019 Program & Proceedings (plantcanada.ca)

Résumé en langage clair

Managing clubroot disease of canola in the Canadian prairies become a major concern since several new pathotypes, such as 3A, 2B, 3D etc. based on the Canadian Clubroot Differential set, have been identified. Clubroot disease in canola widely managed with major gene or qualitative resistance. While transferring qualitative resistance is effective to single pathotype but qualitative resistance could be effective to multiple pathotypes. Vegetable species B. rapa and B. oleracea are considered major source of qualitative and quantitative resistance of clubroot disease, respectively. In this study, genotyping-by-sequencing (GBS) method was used to construct a high-density genetic map and identify QTLs for clubroot resistance to three novel pathotypes 2B, 3A and 3D derived from a backcross (BC) progeny of the cabbages variety ECD 11 (resistant source) and a doubled haploid line TO10000DH3 (susceptible source). A total of 42,923 SNPs were identified from 92 BC1 population, where 12,359 SNPs found polymorphic to parental lines. A total of 49,165.6 cM genetic map was constructed on nine chromosomes by 5,913 high quality polymorphic SNPs. Six QTLs were detected for resistance to pathotype 2B, designated as Rcr-O-C11, Rcr-O-C1-2, Rcr-O-C1-3 on chromosome C1, Rcr-O-C2-1 on C2, Rcr-O-C3-1on C3, Rcr-O-C8-1 on C8, with 4.2–5.8 LOD, and phenotypic variation explained (PEV) of 15.5–20.7%. Seven QTLs were detected for resistance to pathotype 3A, designated as Rcr-O-C3-2, Rcr-O-C3-3, Rcr-O-C3-4, Rcr-O-C35, Rcr-O-C3-6and Rcr-O-C3-7 on chromosome C3, Rcr-O4-C3 on C4 with 4.3–5.1 LOD, and PEV of 15.7–18.4%. A single QTL was detected for resistance to pathotype 3D, designated as Rcr-O-C4-1 on chromosome C4 with 4.5 LOD, and PEV of 16.6%. SNP markers identified associated with these 14 QTLs can be used for introgression and marker assisted molecular breeding for clubroot resistance in canola.

Résumé

Managing clubroot disease of canola (Brassica napus) in the Canadian prairies become a major concern since several new pathotypes, such as 3A, 2B, 3D etc. based on the Canadian Clubroot Differential set, have been identified. Clubroot disease in canola widely managed with major gene or qualitative resistance. While introgressing qualitative resistance is effective to single pathotype but qualitative resistance could be effective to multiple pathotypes. B. rapa and B. oleracea are considered major source of qualitative and quantitative resistance of clubroot disease, respectively. In this study, genotyping-by-sequencing (GBS) method was used to construct a high-density genetic map and identify QTLs for clubroot resistance to three novel pathotypes 2B, 3A and 3D derived from a backcross (BC) progeny of the cabbages variety ‘Badger Shipper’ (ECD 11) (resistant source) and a double haploid line TO10000DH3 (susceptible source). A total of 42,923 SNPs were identified from 92 BC1 population, where 12,359 SNPs found polymorphic to parental lines. A total of 49,165.6 cM genetic map was constructed on nine chromosomes by 5,913 high quality polymorphic SNPs. Six QTLs were detected for resistance to pathotype 2B, designated as Rcr-O-C11, Rcr-O-C1-2, Rcr-O-C1-3 on chromosome C1, Rcr-O-C2-1 on C2, Rcr-O-C3-1on C3, Rcr-O-C8-1 on C8, with 4.2–5.8 LOD, and phenotypic variation explained (PEV) of 15.5–20.7%. Seven QTLs were detected for resistance to pathotype 3A, designated as Rcr-O-C3-2, Rcr-O-C3-3, Rcr-O-C3-4, Rcr-O-C35, Rcr-O-C3-6and Rcr-O-C3-7 on chromosome C3, Rcr-O4-C3 on C4 with 4.3–5.1 LOD, and PEV of 15.7–18.4%. A single QTL was detected for resistance to pathotype 3D, designated as Rcr-O-C4-1 on chromosome C4 with 4.5 LOD, and PEV of 16.6%. SNP markers identified associated with these 14 QTLs can be used for introgression and marker assisted molecular breeding for clubroot resistance in canola.

Date de publication

2019-07-07

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