Coat protein and movement protein based characterization of Lima bean yellow mosaic virus disease in Karnataka

Yellow mosaic disease caused by a Begomovirus has become an important production constraint in lima bean cultivation in Karnataka. The begomovirus causes Lima bean Yellow Mosaic Virus (LYMV), was characterized by sequencing the CP and MP genes. Distinct Viral gene specific PCR product corresponding to CP and MY gene similar to 1000 bp and similar to 900 bp was obtained. The PCR product were sequenced and compared with the reference Begomoviruses sequences from the NCBI blast database. LYMV (GKVK isolate) shared highest nucleotide identity (98%) with Horsegram yellow mosaic virus (HgYMV) of French bean isolate (Accession No. AM932425.1). Phylogenetic analysis of CP and MP gene sequences of LYMV-GKVK isolate showed that LYMV-GKVK clustered with isolates of HgYMV Horsegram and French bean isolates of Tamil Nadu, Srilanka, Karnataka. Based on Nucleotide Identity begomovirus infecting lima bean at Bangalore is to be considered as strain of HgYMV. The disease was also successfully transmitted to French bean and Horsegram when experimentally transmitted using whitefly vector. Therefore, the begomovirus causing yellow mosaic disease of lima bean is considered as strain of HgYMV. Lima bean is infected by Mungbean Yellow Mosaic India Virus (MYMIV) according to earlier reports whereas our study the reports the infection of HgYMV on Lima bean from Karnataka. Thus it is concluded that Lima bean is infected by both MYMIV and HgYMV in different geographical locations.