Fine Mapping and Functional Analysis of Major QTL, <i>CRq</i> for Clubroot Resistance in Chinese Cabbage (<i>Brassica rapa</i> ssp. <i>pekinensis</i>)
Xiaochun Wei,
Jundang Li,
Xiaowei Zhang,
Yanyan Zhao,
Ujjal Kumar Nath,
Lixia Mao,
Zhengqing Xie,
Shuangjuan Yang,
Gongyao Shi,
Zhiyong Wang,
Baoming Tian,
Henan Su,
Zhiyuan Yang,
Fang Wei,
Yuxiang Yuan
Affiliations
Xiaochun Wei
Institute of Horticulture, Henan Academy of Agricultural Sciences, Graduate T&R Base of Zhengzhou University, Zhengzhou 450002, China
Jundang Li
Institute of Horticulture, Henan Academy of Agricultural Sciences, Graduate T&R Base of Zhengzhou University, Zhengzhou 450002, China
Xiaowei Zhang
Institute of Horticulture, Henan Academy of Agricultural Sciences, Graduate T&R Base of Zhengzhou University, Zhengzhou 450002, China
Yanyan Zhao
Institute of Horticulture, Henan Academy of Agricultural Sciences, Graduate T&R Base of Zhengzhou University, Zhengzhou 450002, China
Ujjal Kumar Nath
Department of Genetics and Plant Breeding, Bangladesh Agricultural University, Mymensingh 2202, Bangladesh
Lixia Mao
Institute of Horticulture, Henan Academy of Agricultural Sciences, Graduate T&R Base of Zhengzhou University, Zhengzhou 450002, China
Zhengqing Xie
Henan International Joint Laboratory of Crop Gene Resources and Improvement, School of Agricultural Sciences, Zhengzhou University, Zhengzhou 450001, China
Shuangjuan Yang
Institute of Horticulture, Henan Academy of Agricultural Sciences, Graduate T&R Base of Zhengzhou University, Zhengzhou 450002, China
Gongyao Shi
Henan International Joint Laboratory of Crop Gene Resources and Improvement, School of Agricultural Sciences, Zhengzhou University, Zhengzhou 450001, China
Zhiyong Wang
Institute of Horticulture, Henan Academy of Agricultural Sciences, Graduate T&R Base of Zhengzhou University, Zhengzhou 450002, China
Baoming Tian
Henan International Joint Laboratory of Crop Gene Resources and Improvement, School of Agricultural Sciences, Zhengzhou University, Zhengzhou 450001, China
Henan Su
Institute of Horticulture, Henan Academy of Agricultural Sciences, Graduate T&R Base of Zhengzhou University, Zhengzhou 450002, China
Zhiyuan Yang
School of Materials Science and Engineering, Central South University, Changsha 410083, China
Fang Wei
Institute of Horticulture, Henan Academy of Agricultural Sciences, Graduate T&R Base of Zhengzhou University, Zhengzhou 450002, China
Yuxiang Yuan
Institute of Horticulture, Henan Academy of Agricultural Sciences, Graduate T&R Base of Zhengzhou University, Zhengzhou 450002, China
Clubroot disease caused by Plasmodiophora brassicae is one of the major threats to Brassica crops. New clubroot resistant varieties of Chinese cabbage (B. rapa ssp. pekinensis) have been developed through breeding, but the underlying genetic mechanism of clubroot resistance is still unclear. In this study, two Chinese cabbage DH lines, clubroot-resistant Y635-10 and susceptible Y177-47 were crossed to develop F2 population for fine mapping and cloning resistance gene CRq. After sequence analysis, the expression vector was constructed by gateway technology and transferred into Arabidopsis thaliana for functional characterization. Bulked segregant analysis sequencing (BSA-seq) confirmed that CRq is located in the 80 kb genomic region on chromosome A03 between markers GC30-FW/RV and BGA. In silico tools confirmed that the gene length was 3959 bp with 3675 bp coding sequences (CDs), and it has three exons and two introns. In addition, we found 72bp insertion in the third exon of CRq in the susceptible line. We developed and verified functional marker Br-insert1, by which genotyping results showed that 72bp insertion might lead to the destruction of the LRR region of Y177-47, resulting in a loss of resistance relative to clubroot. The results of genetic transformation showed that the roots for wild-type Arabidopsis thaliana were significantly enlarged compared with T2 generation transgenic Arabidopsis after treatment by P. brassicae spores, and transgenic Arabidopsis had certain resistance. Therefore, CRq is a candidate gene of clubroot disease resistance in Chinese cabbage, which could be used as a reference for elucidating disease resistance mechanisms and the marker-assisted breeding of clubroot resistant varieties.
