Molecular Characterization of sweet potato feathery mottle virus

Abstract

A study on “Molecular characterization of Sweet potato feathery mottle virus” was conducted at the ICAR- Central Tuber Crop Research Institute, Sreekariyam, Thiruvananthapuram during 2016-2017. During the study 45 accessions of sweet potato from different fields of ICAR- CTCRI were selected and different symptoms of Sweet potato feathery mottle virus infection were recorded. The study reveals that the rate of infection is still prevailing in Kerala having high symptom severity due to combination with other potyviruses and increased aggressiveness as compared to earlier years because of the presence to different strains. Total RNA was isolated from all samples and used for RT-PCR analysis by degenerate primers for potyviruses and specific primers for SPFMV to differentially identify the presence of SPFMV. From the 45, five were confirmed as SPFMV positive. Among this amplified products obtained from sample SH710 was sequenced. From the 8 clones sequenced 3 different isolates of SPFMV is obtained, Sweet potato feathery mottle virus isolate SPFMV-O-Arg polyprotein gene (NCBI ID: KF386013.1) from Argentina, Sweet potato feathery mottle virus isolate CW137 (NCBI ID: KP115608.1) from Korean and Sweet potato feathery mottle virus isolate Shanxi2 coat protein gene (NCBI ID: HQ844123.1) from China, these are further belongs to broad class of Ordinary and Russet crack and East African. It further showed the possibility of presence of RC-strain O-strain and EA-strain in Kerala. To identify the phylogenetic relationship of the sequenced samples with that of available accessions, dendrograms were made using MEGA 7.0.26 software and the tree showed that sequences has variability eventhough lies within the group. By restriction analysis and sequence analysis, variability was recorded within SPFMV in Trivandrum.