Occurrence of cucumber mosaic virus Subgroup I on different plant families in Himachal Pradesh and its infection to new hosts

Cucumber mosaic virus (CMV) has been recorded worldwide, infecting more than 1200 plant species including weeds. In this study, 23 samples of bell pepper, squash, tomato, ornamental (calla lily, French hydrangea, spider lily) and weeds (Arrowleaf dock, Spanish needle) hosts originating from Himachal Pradesh were examined. 20 of 23 samples were identified CMV positive based on electron microscopy, bio-assay, RT-PCR assay and sequence analyses of coat protein (CP) gene. The CMV-CP gene sequences from eight isolates cloned and sequenced in this study shared 96–100% amino acid sequence identities with CMV Subgroup I isolates. This study forms the first report of the natural occurrence of CMV on squash and a weed host, Arrowleaf dock ( Rumex hastatus ), in India as well as the occurrence of CMV Subgroup I in the cooler hilly regions of India. These findings suggest the expansion of the host range as well as ecological niche of CMV.