Indian Journal of Virology

Sweet potato [Ipomoea batatas L. (Lam] is the seventh most important food crop in the world and the third most economically important root crop after potato and cassava. In India,.0.93 million tons of sweet potatoes were produced during 2005. Productivity of sweet potato is about 8.7 t ha⁻¹ which is below the world average of 18 t ha⁻¹. Viral diseases are one of the several production constraints of sweet potato in India. A total of 19 viruses have been reported on sweet potato world over. In India, 10 - 50 per cent incidence of sweet potato feathery mottle (SPFMV) has been reported. In the present study the SPFMV coat protein gene was amplified, cloned in pGEM-T vector and sequenced. Analyses of CP gene sequence indicated that the SPFMV isolate occurring in India is closely related to SPFMV Egyptian strain. Further, the coat protein gene was cloned in bacterial expression vector pET 32b and transformed in to Escherichia coli. Protein expression was induced with 0.1% IPTG and purified protein was injected into rabbit intramuscularly and polyclonal antiserum was produced. The antiserum could detect SPFMV in indirect ELISA and DIBA at 1:1000 dilutions. ELISA and DIBA protocols for detection of SPFMV using the polyclonal antiserum has been standardized and validated by checking SPFMV in sweet potato field samples. SPFMV was also detected through RT-PCR, immuno capture RT-PCR and NASH using non-radio active labeled kit. The possibility of using the appropriate diagnostic technique for indexing of sweet potato planting materials is discussed in the paper.