Characterization of Cucumber mosaic virus infecting snake gourd and bottle gourd in India

Snake gourd and bottle gourd are the common cucurbitaceous vegetables consumed in India that are prone to viral infections under field conditions. During our field survey in Southern India in 2012-14, the symptoms viz., stunted growth, mosaic mottling, puckering and chlorosis in these crops were observed. Incidences of virus-like symptoms ranging between 63 and 88% were observed in three different locations. Based on the mechanical inoculations on their respective host, plants produced symptoms similar to those under field conditions. Samples tested with DAS-ELISA using CMV polyclonal antiserum were found positive for CMV. The occurrence of CMV was further confirmed by amplification of coat protein gene of CMV using RT-PCR assays. The sequence analysis of coat protein gene revealed highest nucleotide identity of > 92% with CMV subgroup IB isolates. Coding regions from CMV RNA 1, RNA 2 and RNA 3 genomic fragments were cloned and sequenced. Phylogenetic analysis of RNA1, RNA 2 and RNA 3 from CMV infecting snake gourd and bottle gourd showed close relatedness with Italian isolate that infect Capsicum rather than Asian isolates of CMV from India, Malaysia, China and Japan. The characterization of CMV from snake gourd and bottle gourd pertaining to biological, serological and molecular attributes are presented.