[Cotton Leaf Curl Multan Betasatellite as a Tool to Study the Localization of Geminiviruses in Plants]

Cotton leaf curl Multan betasatellite (CLCuMB) is a ubiquitous betasatellite commonly found along with cotton leaf curl disease (CLCuD) associated begomoviruses in the Old World. It has a promiscuous replicative nature and trans-replicated by a diverse range of geminiviruses. CLCuMB encodes a single ORF, βCl, in the complementary direction and has pathogenicity, symptoms determinant, suppressor of post-transcription and transcription gene silencing functions. After substituting the βC1 gene with the target gene, it has been used successfully as a gene delivery vector. In the present study, the βC1 gene of CLCuMB was substituted with the green fluorescent protein (GFP) gene, and the resulting construct utilized as a reporter vector to decipher in planta localization of geminiviruses. The recombinant CLCuMB expressing GFP (CLCuMB-GFP) was co-inoculated to Nicotiana benthamiana plants either with Cotton leaf curl Kokharan virus (CLCuKoV) alone or in a combination with the wild type CLCuMB to investigate the objectives of the study. Results showed that CLCuKoV successfully supported the replication and systemic movement of CLCuMB-GFP either alone or in the presence of wild type CLCuMB. The presence of CLCuMB-GFP was readily detected with PCR and Southern blot hybridization. The modified CLCuMB may serve as a tool useful for in planta localization of geminiviruses.