1992 Volume 58 Issue 2 Pages 298-304
A virus, designated NFU, isolated from bean plants (Phaseolus vulgaris cv. Kentucky Wonder) with severe vine necrosis (Turugare-byo) in Fukushima Prefecture was compared with a seed-borne isolate of bean yellow mosaic virus (BYMV-SB) from broad bean. When mechanically inoculated onto test plants, NFU caused severe necrotic symptoms on bean, broad bean and pea, whereas BYMV-SB caused mosaic symptoms. Isolate NFU was transmitted in a nonpersistent manner by Myzus persicae but not through seed. Virus particles and inclusion bodies showed typical potyvirus morphology when examined by electron microscopy. Analysis of a purified preparation of NFU by SDS-PAGE revealed two protein bands with relative molecular weights of 34k and 37k. In immunoelectron microscopy with some antisera against BYMV and clover yellow vein virus (CYVV), NFU was serologically more closely related to CYVV than BYMV. In enzyme linked immunosorbent assay (ELISA), agar gel diffusion test, immunoelectron microscopy, and Western blotting, NFU and BYMV-SB were serologically related but antigenically different. Based on these results NFU was identified as a strain of CYVV. To find the weed-host plants of CYVV causing necrosis on bean, wild plants around bean fields were collected and assayed by ELISA and sap inoculation onto bean; eight wild plants (Plantago asiatica, Veronica persica, Glechoma hederacea, Lamium amplexicaule, Perilla frutescens, Trifolium repens, T. pratense, Iris sp.) were infected with severe CYVV and thought to be important primary sources of inoculum for bean vine necrosis.
