Identification of host targets for putative disulfide isomerase effector from Plasmodiophora brassicae reveals novel mechanisms of clubroot pathogenesis

Effector proteins secreted by pathogens play critical roles in suppressing host immunity and facilitating infection. In this study, we identified and characterized the putative disulfide-isomerase effector protein Pb001683 from the clubroot pathogen Plasmodiophora brassicae , a major threat to cruciferous crops. Transgenic plants overexpressing Pb001683 exhibited increased susceptibility to P. brassicae , supporting its role in pathogenicity. Subcellular localization analysis showed that Pb001683 localizes to the endoplasmic reticulum (ER) and nucleus in host cells. Co-immunoprecipitation coupled with mass spectrometry (CoIP-MS) analysis identified 353 candidate host proteins associated with Pb001683, suggesting a broad network of potential host targets. Gene Ontology (GO) enrichment indicated that these proteins were enriched in processes such as carboxylic acid metabolic process and oxoacid metabolic process. The interaction between Pb001683 and BrCYP83A1 was further validated using the split-luciferase assay. In addition, reactive oxygen species (ROS) assays showed that Pb001683-overexpressing plants exhibited elevated ROS levels compared with the control. Collectively, these findings provide new insights into the molecular mechanisms of clubroot pathogenesis and highlight potential strategies for enhancing crop resistance by targeting effector-host interactions. • Pb001683, an effector from P. brassicae , enhances host susceptibility to clubroot disease. • Pb001683 interacts with host proteins involved in oxoacid metabolic process and increases ROS levels. • Targeting Pb001683-host protein interactions may lead to new strategies for clubroot disease control.