Blackeye cowpea mosaic virus from asparagus bean (Vigna sesquipedalis) in Thailand and Malaysia, and their relationships to a Japanese isolate.

Abstract

A sap-transmissible virus isolated from infected asparagus bean (Vigna sesquipedalis) in Thailand and Malaysia had relatively wide host range, but the plants showed systemic symptom were limited to Leguminosae. In asparagus bean juice, infectivity was lost by heating at 55-65C for 10 minutes, by diluting at 10-4-10-5, and by aging at 20C for 1-3 days. The virus was flexuous filaments of about 750nm in length, and was transmitted by aphids in a non-persistent manner. The isolate from Thaliand was seed-borne in cowpea but not in asparagus bean. In double-diffusion tests in agar gel plates containing lithium 3, 5-diiodosalicylate, the virus reacted strongly with antiserum to the Florida isolate of blackeye cowpea mosaic virus (B1CMV) and bean common mosaic virus (BCMV), but not with antiserum to the Morocco isolate of cowpea aphid-borne mosaic virus (CAMV). From these results, this virus was identified as B1CMV. In double diffusion test, the isolate of CAMV from Tokyo (Tsuchizaki et al., 1970) reacted strongly with antisera to the Florida isolate of B1CMV, the Thailand isolate of B1CMV, but not with antiserum to the Morocco isolate of CAMV. Based on the results of serological tests, the Tokyo isolate previously designated as CAMV was considered an isolate of B1CMV.