Integrative Transcriptome, Small RNA, Degradome and Phytohormone Analysis of Brassica rapa L. in Response to Clubroot Disease

Background and aim Clubroot is an infectious root disease caused by Plasmodiophora brassicae in Brassica crops, which can cause immeasurable losses. We aimed to explore the infection mechanism under P. brassicae integrating transcriptome, small RNA, degradome and phytohormone technology . Result In this study, root samples of Brassica rapa resistant line BrT24 (R-line) and susceptible line Y510-9 (S-line) were collected at four different time points for cytological, transcriptome, miRNA and degradome investigations. We found the critical period of disease resistance and infection at 0 - 3 days and 9 - 20 days, respectively. Based on our finding we further analyzed the data of 9 d vs 20 d of S-line and predicted the key genes ARF8 , NAC1 , NAC4 , TCP10 , SPL14 , REV and ATHB related to clubroot disease development and regulating disease resistance mechanisms. These genes are mainly related to auxin, cytokinin, jasmonic acid and ethylene cycles. We proposed a regulatory model of plant hormones under the mRNA-miRNA regulation in the critical period of P. brassicae infection by using integrative transcriptome, small RNA, degradome and phytohormone technology. Conclusion Our integrative analysis found that the bra-miR164/NAC1/4 , bra-miR319/TCP10 and bra-miR167/ARF8 were associated with clubroot symptoms development, which provide new insights into the regulation relationship of miRNA and plant hormones during the process of disease infection .