Biological, antigenic and genomic relationships among the virus isolates causing mosaic disease of sugarcane in South India

The virus isolates causing mosaic disease of commercial sugarcane around Tirupati (Chittoor district, Andhra Pradesh (AP)), Tanuku (West Godavari district, AP), Hospet (Bellary district, Karnataka) and Coimbatore (Tamil Nadu) were propagated on Sorghum bicolor cv, Rio by sap inoculation and also through vegetative propagules of sugarcane. In host range studies, the four isolates infected all the 11 tested sorghum differentials with per cent infection ranging from 10 to 100, but they failed to infect Pennisetum typhoides, Zea mays, Eleusine coracana and Triticum aestivum, The antigenic relationships among these isolates determined by employing agar gel double diffusion (AGDD), direct antigen coating-enzyme-linked immunosorbent assay (DAC-ELISA) and electroblot immunoassay (EBIA) tests using antiserum of Tirupati (Chittoor district, AP) isolate (sugarcane streak mosaic virus, SCSMV-AP) revealed that the other three isolates are antigenically similar to SCSMV-AP, This was further confirmed by slot-blot hybridization using radioactive nucleic acid probe (pSV-7) specific to 3'-UTR and C-terminal portions of coat protein gene of SCSMV-AP, The heterologous isolates reacted similarly with the probe, The results demonstrated that the virus isolates causing mosaic disease of sugarcane in South Indian states are pathotypes of recently characterized SCSMV-AP, a new member of the proposed genus Tritimovirus of the family Potyviridae