Genetic Mapping and Characterization of the Clubroot Resistance Gene in .

Clubroot, a significant soil-borne disease, severely impacts the productivity of cruciferous crops. The identification and development of clubroot resistance (CR) genes are crucial for mitigating this disease. This study investigated the genetic inheritance of clubroot resistance within an F progeny derived from the cross of a resistant parent, designated "377", and a susceptible parent, designated "12A". Notably, "377" exhibited robust resistance to the "KEL-23" strain of , the causative agent of clubroot. Genetic analyses suggested that the observed resistance is controlled by a single dominant gene. Through Bulked Segregant Analysis sequencing (BSA-seq) and preliminary gene mapping, we localized the CR gene locus, designated as , to a 1.30 Mb genomic segment on chromosome A08, flanked by the markers "333" and "sau332-1". Further fine mapping precisely narrowed down the position of to a 173.8 kb region between the markers "srt8-65" and "srt8-25", where we identified 22 genes, including with a TIR-NBS-LRR domain and with an LRR domain. Quantitative reverse transcription polymerase chain reaction (qRT-PCR) analyses confirmed that both and exhibit increased expression levels in the resistant parent "377" following inoculation with , thereby underscoring their potential as key genes implicated in -mediated clubroot resistance. This study not only identifies molecular markers associated with but also enriches the genetic resources available for breeding programs aimed at enhancing resistance to clubroot.