Leek yellow stripe virus isolated from an ornamental Allium plant in Japan.

Abstract

A potyvirus isolated from an ornamental Allium ampeloprasum cv. ‘Murasame’ showing mosaic and white necrosis on the leaves, collected in Kurashiki, was identified as an isolate of leek yellow stripe virus (LYSV). LYSV was transmitted by aphids, Myzus persicae and Aphis gossypii, in a non-persistent manner and by sap-inoculation to 6 of 49 species from 4 of 11 families. A. ampeloprasum cv. ‘Miyako’ and A. giganteum were infected systemically and produced mosaic symptoms on leaves. Local lesions were produced on Chenopodium amaranticolor and C. quinoa, whereas systemic latent infection was produced on Spinacia oleracea and latent local infection was on Gomphrena globosa. Sap from the diseased C. quinoa was infective after 10min heating at 50C but not 55C, after dilution to 10-3 but not 10-4 and after 4 days but not 8 days at 20C. The virus particles were filamentous, about 820nm long. The virus was purified from locally infected C. quinoa leaves by clarifying sap extracted in 0.5M phosphate buffer with chloroform/carbon tetrachloride mixture followed by PEG precipitation, differential centrifugations through sucrose cushion and sucrose density gradient centrifugation. LYSV contained a single protein species of mol. wt. 36, 500 daltons. In ultrathin sections of the virusinfected C. quinoa leaves, cytoplasmic inclusions containing pinwheels, scrolls and short curved laminated aggregates were observed in the cytoplasms. LYSV reacted with LYSV antiserum donated from Ir.D.Z. Maat (the Netherlands) and the antiserum to LYSV produced by immunizing a rabbit (titer: 1/512), but not with antisera to bean yellow mosaic virus, clover yellow vein virus, freesia mosaic virus, iris mild mosaic virus, iris severe mosaic virus, narcissus yellow streak virus, onion yellow dwarf virus, turnip mosaic virus and potato virus Y.