Fine mapping and candidate gene analysis of CRA3.7 conferring clubroot resistance in Brassica rapa

• Published in: Theoretical and applied genetics 2022-12, Vol.135 (12), p.4541-4548
• Main Authors: Pang, Wenxing, Zhang, Xue, Ma, Yinbo, Wang, Yingjun, Zhan, Zongxiang, Piao, Zhongyun
• Format: Article
• Language: English
• Subjects: Agricultural research; Agriculture; Biochemistry; Biomedical and Life Sciences; Biotechnology; Brassica - genetics; Brassica oleracea; Brassica rapa; Brassica rapa - genetics; Chinese cabbage; Chromosome Mapping; Clubroot; Control; Cultivars; Diseases and pests; Gene expression; Gene mapping; Genetic aspects; Genetic Association Studies; Genomes; Germplasm; Humans; Inbreeding; Inoculation; Life Sciences; Marker-assisted selection; Methods; Original Article; Parasitic diseases; Plant Biochemistry; Plant Breeding; Plant Breeding/Biotechnology; Plant Diseases - genetics; Plant Genetics and Genomics; Plant immunology; Plasmodiophorida - genetics; Quantitative trait loci; Recombinants
• ISSN: 0040-5752; 1432-2242
• DOI: 10.1007/s00122-022-04237-2

Key message In this study, we fine-mapped a clubroot resistance gene CRA3.7 in Chinese cabbage and developed its closely linked marker syau-InDel3008 for marker-assisted selection in CR cultivars breeding. Chinese cabbage is an important leafy vegetable rich in many nutrients widely grown in China. Clubroot disease caused by an obligate biotrophic pathogen Plasmodiophora brassicae was rapidly spread and challenged to Chinese cabbage production. A clubroot resistance (CR) gene, CRA3.7 , was mapped on chromosome A03 of Brassica rapa . A Chinese cabbage line ‘CR510’, which harbor homozygous resistance locus CRA3.7 was selected from a BC4F3 family. ‘CR510’ was crossed with a clubroot susceptible Chinese cabbage inbred line ‘59-1’. Total 51 recombinant plants were identified from an F 2 population including 3000 individuals. These recombinants were selfed and the clubroot resistance of F 2/3 families was evaluated. Finally, a clubroot resistance gene CRA3.7 was fine-mapped to an interval of approximately 386 kb between marker syau-InDel3024 and syau-InDel3008. According to the reference genome, total 54 genes including five encoding the TIR-NBS-LRR proteins was annotated in the fine-mapped region. Further, nine candidate’s gene expression in parental lines at 7, 14 and 21 days after inoculation of P. brassicae were evaluated. Bra019376, Bra019401, Bra019403 and Bra019410 are highly expressed in ‘CR510’ than ‘59-1’. Gene sequence of Bra019410 from ‘CR510’ was cloned and identified different from CRa. Therefore, Bra019376 , Bra019401 , Bra019403 and Bra019410 are the most likely candidates for CRA3.7 . Our research provides a valuable germplasm resource against P. brassicae Pb3 and CRA3.7 closely linked marker for marker-assisted selection in CR cultivars breeding.