Partial characterization of a Potyvirus causing bract mosaic of banana in Andhra Pradesh

A virus causing conspicuous dark streaks on the inflorescence bracts, purple colored streaks on petioles and pseudostem, and occasional interveinal chlorotic streaks on leaves of banana in West Godavari (Andhra Pradesh) was purified to homogeneity. Purified virus preparations had A_260/280 and A_max/min ratios of 1.25 and 1.10, respectively. Coat protein of the virus resolved as one major polypeptide with an estimated molecular weight (M_r) of 38 kDa and three minor polypeptides of M_r 63, 53 and 22 kDa, in a 12% SDS-PAGE. In direct antigen coating (DAC)-ELISA, the virus reacted positively with the antisera of Bean yellow mosaic, Blackeye cowpea mosaic, Lettuce mosaic, Pepper mild mottle, Pepper mottle, Peanut stripe, Sugarcane mosaic, Pea seed-borne mosaic, Potato virus-Y and Datura leaf distortion (DLDV) viruses. In electro-blot immunoassay (EBIA), 38 and 63 kDa polypeptides reacted with DLDV antiserum. In serosurvey of 55 infected banana plant samples, 20 tested positive with DLDV antiserum, 14 gave positive reaction with CMV-B antiserum, the rest were negative with respect to DLDV and CMV-B; none tested positive to both DLDV and CMV-B. Based on the results of present studies, the virus was identified as a potyvirus, which might be similar to Banana bract mosaic virus (BBrMV) reported from the Philippines.