A hitherto unreported yellow vein clearing disease of citrus in India and its viral etiology

Abstract

Yellow vein clearing disease of citrus (CYVCD) was first observed in an Experimental Research Orchard at Abohar in Punjab on a citrus cultivar Etrog Citron. Later, the disease was observed in citrus plantation from Ludhiana, Pune and Anand on several commercial and germ plasm species of citrus. The disease was transmitted to 16 citrus cultivars of citrus by grafting and was also transmitted mechanically from infected Etrog Citron to healthy Mosambi seedlings and to Phaseolus vulgaris var. saxa, singtamey, gheusemi and Chenopodium quinoa. P.vulgaris cv. Singtamey and C.quinoa developed local lesions on inoculated leaves but the infection became systemic in P. vulgaris. The TIP of the virus was 62° C, DEP 10.2 and LlV 2 h at room temperature. The virus was purified and filamentous particles measuring 685x14 nm were observed in electron microscope. Polyclonal antibodies were raised in rabbit. IgG from whole antiserum were isolated and conjugated with alkaline phosphatase. DAS and DAC-ELISA and ISEM techniques were standardized for virus detection. The virus had a coat protein of 32 KDa and has been tentatively named as Citrus yellow vein clearing virus (CYVCV).