Transcriptome analysis of Chinese cabbage at the initial stage of Plasmodiophora brassicae infection

Abstract Clubroot disease is a widespread disease in China caused by the infection of Plasmodiophora brassicae (P. brassicae), which significantly reduces the yield of Chinese cabbage (Brassica rapa L. ssp. pekinensis). However, the molecular mechanism of Chinese cabbage’s resistance to clubroot dis-ease is still unclear. So, it is important to study the differentially expressed genes at the initial stage of P. brassicaeinfection. In this study, it was found that zoospores were firstly invaded hair roots on the 8th day after inoculating with 1×107 spores/mL P. brassicae. Transcriptome analysis found that the early interaction between Chinese cabbage and P. brassicae caused significant expression change of some genes, such as NBS-LRRs, pathogenesis-related protein, etc, which was verified by quantitative reverse-transcription polymerase chain reaction (qRT-PCR). Among them, we also found that peroxidase (POD), salicylic acid (SA) and jasmonic acid (JA) may be important signal molecules in the resistance to P. brassicaeinfection in Chinese cabbage. This study provides important clues for understanding the molecular mechanism of resistance to clubroot disease in Chinese cabbage.