Affiliation:
1. State Key Laboratory of Vegetable Biobreeding, Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing 100081, China
2. Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AB T6G 2P5, Canada
Abstract
The soil-borne pathogen Plasmodiophora brassicae is the causal agent of clubroot, a major disease in Chinese cabbage (Brassica rapa ssp. pekinensis). The host’s resistance genes often confer immunity to only specific pathotypes and may be rapidly overcome. Identification of novel clubroot resistance (CR) from germplasm sources is necessary. In this study, Bap246 was tested by being crossed with different highly susceptible B. rapa materials and showed recessive resistance to clubroot. An F2 population derived from Bap246 × Bac1344 was used to locate the resistance Quantitative Trait Loci (QTL) by Bulk Segregant Analysis Sequencing (BSA-Seq) and QTL mapping methods. Two QTL on chromosomes A01 (4.67–6.06 Mb) and A08 (10.42–11.43 Mb) were found and named Cr4Ba1.1 and Cr4Ba8.1, respectively. Fifteen and eleven SNP/InDel markers were used to narrow the target regions in the larger F2 population to 4.67–5.17 Mb (A01) and 10.70–10.84 Mb (A08), with 85 and 19 candidate genes, respectively. The phenotypic variation explained (PVE) of the two QTL were 30.97% and 8.65%, respectively. Combined with gene annotation, mutation site analysis, and real-time quantitative polymerase chain reaction (qRT-PCR) analysis, one candidate gene in A08 was identified, namely Bra020861. And an insertion and deletion (InDel) marker (co-segregated) named Crr1-196 was developed based on the gene sequence. Bra013275, Bra013299, Bra013336, Bra013339, Bra013341, and Bra013357 in A01 were the candidate genes that may confer clubroot resistance in Chinese cabbage. The resistance resource and the developed marker will be helpful in Brassica breeding programs.
Funder
National Key Research and Development Program of China
China Agriculture Research System
Agricultural Science and Technology Innovation Program of the Chinese Academy of Agricultural Sciences
Central Public-interest Scientific Institution Basal Research Fund
Reference71 articles.
1. Pang, W., Fu, P., Li, X., Zhan, Z., Yu, S., and Piao, Z. (2018). Identification and mapping of the clubroot resistance gene CRd in Chinese cabbage (Brassica rapa ssp. pekinensis). Front. Plant Sci., 9.
2. Research status of clubroot (Plasmodiophora brassicae) on cruciferous crops in China;Chai;Can. J. Plant Pathol.,2014
3. Clubroot disease on Brassica crops in India;Bhattacharya;Can. J. Plant Pathol.,2014
4. Clubroot in Australia: The history and impact of Plasmodiophora brassicae in Brassica crops and research efforts directed towards its control;Donald;Can. J. Plant Pathol.,2014
5. Genetics and breeding for clubroot resistance in Canadian spring canola (Brassica napus L.);Rahman;Can. J. Plant Pathol.,2014