Abstract
The rapid spread of clubroot disease, which is caused by Plasmodiophora brassicae, threatens Brassicaceae crop production worldwide. Breeding plants that have broad-spectrum disease resistance is one of the best ways to prevent clubroot. In the present study, eight Chinese cabbage germplasms were screened using published clubroot-resistant (CR) loci-/gene-linked markers. A CR gene Crr3 potential carrier “85-74” was detected which linked to marker BRSTS61; however, “85-74” shows different responses to local pathogens “LAB-19,” “LNND-2,” and “LAB-10” from “CR-73” which harbors Crr3. We used a next-generation sequencing-based bulked segregant analysis approach combined with genetic mapping to detect CR genes in an F2 segregant population generated from a cross between the Chinese cabbage inbred lines “85-74” (CR) and “BJN3-1” (clubroot susceptible). The “85-74” line showed resistance to a local pathogen “LAB-19” which was identified as race 4; a genetic analysis revealed that the resistance was conferred by a single dominant gene. The CR gene which we named CRd was mapped to a 60 kb (1 cM) region between markers yau389 and yau376 on chromosome A03. CRd is located upstream of Crr3 which was confirmed based on the physical positions of Crr3 linked markers. The identification of CRd linked markers can be applied to marker-assisted selection in the breeding of new CR cultivars of Chinese cabbage and other Brassica crops.
Highlights
Chinese cabbage (Brassica rapa ssp. pekinensis) is one of the most important leafy head vegetables cultivated in China, Korea, and Japan
The P. brassicae infection starts from primary zoospores releasing and causes root hair infection and primary zoospore or secondary zoospores induce cortical infection leading to the formation of galls on the roots (McDonald et al, 2014)
To characterize CR resources of Chinese cabbage, eight inbred lines of CR Chinese cabbage were genotyped with known CR gene linked markers and infected with 11 different local isolates of P. brassicae
Summary
Chinese cabbage (Brassica rapa ssp. pekinensis) is one of the most important leafy head vegetables cultivated in China, Korea, and Japan. The soil-borne obligate plant pathogen Plasmodiophora brassicae Woronin causes clubroot in Brassica crops, blocking nutrient and water transport (Voorrips et al, 2003). The life cycle of P. brassicae has not been well understood until now. The P. brassicae infection starts from primary zoospores releasing and causes root hair infection and primary zoospore or secondary zoospores induce cortical infection leading to the formation of galls on the roots (McDonald et al, 2014). Crop rotation and application of fluazinam and cyazofamid can effectively reduce the viability of resting P. brassicae spores and prevent infection
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
