Disease Note.

Natural Occurrence of Clitoria Yellow Vein Virus in Calopogomum mucunoides in Malaysia. N. Abdul-Samad, Department of Biochemistry and Microbiology, Universiti Pertanian Malaysia, 43400 Serdang, Selan-gor, Malaysia. Plant Dis. 78:1123. Accepted for publication 30 June 1994. Copyright 1994 The American Phytopathological Society. DOI: 10.1094/PD-78-1123C.

The legume cover crop Calopogomum mucunoides Desv. is an important cover crop in oil palm and rubber estates in Malaysia. Plants with mottled leaves were collected from an open field at Universiti Pertanian Malaysia campus, Serdang, Malaysia. Icosahedral virus particles, about 28 nm in diameter, were observed by electron microscopy; and empty shells and full particles were separated as two bands on sucrose density gradients. Antiserum to the virus with a titer of 1/2,048 in gel immuno-diffusion tests was produced in rabbit in the laboratory. In gel immuno-diffusion tests, precipitin lines with the presence of spurs were formed on reaction to antisera to turnip yellow mosaic virus (TYMV) (ATCC PVAS 256), Desmodium yellow mottle virus (DYMV), and Kennedya yellow mosaic virus (KYMV) (supplied by R. Koenig). Precipitin lines with no spur were observed on reaction against antisera to Clitoria yellow vein virus (CYVV) (supplied by R. Koenig and K. R. Bock) as well as against the homologous antiserum. In reciprocal DAS-ELISA, the two isolates reacted to both antisera. The virus induced a necrotic local lesion and systemic infection when mechanically transmitted to Phaseolus vulgaris L. cv. Blue Lake, and it did not infect Datura stramonium L., Nicotiana glutinosa L., and N. tabacum L. Similar symptoms to those seen in the field were reproducible by inoculation with purified virus to C. mucunoides. Other legumes (Pueraria phaseoloides (Roxb.) Benth., Desmodium ovalifolium Wall., D. heterophylum DC, Centrosema pubescens Benth., Arachis hypogaea L., Vigna sesquipedaiis (L.) Fruw., Cassia occidentalis L., and Phaseolus vulgaris) (1) were also infected with systemic mottle. By these criteria, the virus was identified as an isolate of CYVV. This is the first report of CYVV in C. mucunoides in Malaysia.