Bacterial leaf blight (BLB) caused by Xanthomonas oryzae pv. oryzae (Xoo) has shown a high incidence rate in rice fields in recent years. Rice resistance breeding is considered as the most effective method for achieving economical and sustainable management of BLB disease. The essential basis for resistance breeding is rooted in the exploration of rice resistance genes and the clarification of the molecular mechanisms that underlie Xoo resistance. In our previous research, we showed that Xanthomonas outer protein XopZ and rice oxysterol-binding related protein ORP1C collaboratively regulate the compatible interaction between Xoo strain PXO99 and Nipponbare rice, but the deeper regulatory mechanisms remain unknown. In this study, we successfully constructed ORP1C overexpression rice using the plant binary expression vector pCAMBIA1301. Through a series of virulence and effector translocation detections in Xoo-rice interactions, we revealed that overexpression of the ORP1C gene largely increases rice resistance to multiple Xoo strains from different countries and regions. Mechanistically, ORP1C plays a Xoo resistant role through negatively regulating transcription activator-like effectors (TALEs) translocation, ORP1C has become a potential candidate gene resource for disease-resistant breeding in rice. Further studies also indicated that XopZ and ORP1C collaboratively regulate the compatible interaction of PXO99-Nipponbare by modulating TALEs translocation.
Keywords: Xanthomonas oryzae pv. oryzae; oxysterol-binding related protein ORP1C; rice; transcription activator-like effectors TALEs; translocation.