Interaction Between Tomato Leaf Curl Palampur Virus and Its Associated Betasatellite Enhances Disease Severity in Zucchini

Tomato leaf curl Palampur virus (ToLCPalV, Begomovirus solanumpalampurense, family Geminiviridae) is a highly destructive virus affecting tomato and cucurbits crops in Iran. In this study, we report the first detection of tomato leaf curl betasatellite (ToLCB, Betasatellite solani) in association with ToLCPalV in zucchini plants showing severe disease symptoms in Anbar-Abad, southeastern Iran. Using agroinoculation experiments on zucchini plants with different combinations of ToLCPalV genomic components and ToLCB, we found that plants co-inoculated with DNA-A + DNA-B + ToLCB exhibited more severe symptoms compared to those inoculated with DNA-A + DNA-B or DNA-A + ToLCB. These results suggest that the severe symptoms are due to interactions between ToLCPalV DNA-B and ToLCB. Although both DNA-A + DNA-B and DNA-A + ToLCB induced disease symptoms individually, the resultant symptoms were different between the two treatments. This is the first report of the association of a bipartite begomovirus with a betasatellite in Iran. Given the widespread occurrence of ToLCPalV and the association of ToLCB with different mono- and bipartite geminiviruses including its recent association with a turncurtovirus, further studies are warranted to investigate interaction between ToLCB and mono- or bipartite geminiviruses in southeastern Iran.