Biological and molecular characterization of cucumber mosaic virus isolate causing severe mosaic in Gherkin (Cucumis anguria L.) in India

Abstract

Gherkin (Cucumis anguria L.) is an important cucurbitaceous vegetable crop grown in southern states of India viz., Andhra Pradesh, Karnataka and Tamil Nadu for slicing and pickling. The crop infected by Cucumber mosaic virus (CMV) is a most destructive disease on gherkin growth and yield. During 2013-14 survey revealed that, disease incidence was ranging from16.00 to 59.65 per cent with highest incidence was recorded in Kolar (51.27%) and least was in Bangalore rural (17.15%). The virus can readily be transmitted by sap and aphids on cultivar green long which showed systemic mosaic with dark and light green or with yellow patches with slight puckering. Crop like Ash gourd, Bottle gourd, Bush squash, Cucumber, Muskmelon, Pumpkin, Ridge gourd, Round melon and Chilli also showed mosaic symptoms, Tomato showed shoestring symptom, Chenopodium and Cowpea showed necrotic local lesions upon inoculation with CMV. Virus reacted strongly to cucumovirus specific antisera through DAS-ELISA. PCR product of CMV infected sample with CP-primers indicated∼700bp-DNA and highest nucleotide homology with the strains of CMV subgroup-IB (95-99%) and nucleotide sequence conservation (99%) with AN-strain (subgroup-IB).