Functional characterization of a new ORF βV1 encoded by radish leaf curl betasatellite

Whitefly-transmitted begomoviruses infect and damage a wide range of food, feed, and fiber crops worldwide. Some of these viruses are associated with betasatellite molecules that are known to enhance viral pathogenesis. In this study, we investigated the function of a novel beta V1 protein encoded by radish leaf curl betasatellite (RaLCB) by overexpressing the protein using potato virus X (PVX)-based virus vector in Nicotiana benthamiana. beta V1 protein induced lesions on leaves, suggestive of hypersensitive response (HR), indicating cell death. The HR reaction induced by beta V1 protein was accompanied by an increased accumulation of reactive oxygen species (ROS), free radicals, and HR-related transcripts. Subcellular localization through confocal microscopy revealed that beta V1 protein localizes to the cellular periphery. beta V1 was also found to interact with replication enhancer protein (AC3) of helper virus in the nucleus. The current findings suggest that beta V1 functions as a protein elicitor and a pathogenicity determinant.

Automated summary

The beta V1 protein encoded by radish leaf curl betasatellite (RaLCB) induces cell death and hypersensitive response (HR) in Nicotiana benthamiana, accompanied by increased accumulation of reactive oxygen species (ROS) and HR-related transcripts. The protein localizes to the cellular periphery and interacts with replication enhancer protein (AC3) of the helper virus.