Preliminary Characterization of a Potyvirus, the Causal Agent of Green-Sterile Disease of Guar. M. E.C. REY, Department of Microbiology, University of the Witwatersrand, Johannesburg, P O Wits, 2050. A. SMITH, S. JOHNSON, and S. KHITSANE, Department of Microbiology, University of the Witwatersrand, Johannesburg, P O Wits, 2050. Plant Dis. 79:172-176. Accepted for publication 5 October 1994. Copyright 1995 The American Phytopathological Society 172. DOI: 10.1094/PD-79-0172.

A potyvirus named guar green-sterile virus (GGSV) has been reported to be associated with a disease of guar (Cyamopsis tetragonoloba (L.)) in southern Africa. Symptoms of leaf chlorosis/ localized necrosis and sterility in guar were obtained using a sucrose-gradient purified GGSV preparation for mechanical inoculation. Potyviruses were also isolated from sterile guar plants grown from seed and from mechanically inoculated guar and bean cultivar hosts, which indicates that GGSV is the causal agent of disease symptoms in guar. Polyacrylamide gel electrophoresis, Western blot (immunoblot), scrological analyses, and isolation of an RNA species of approxi-mately 9.4 Kb indicate that GGSV is a potyvirus. Results of mechanical transmissions to bean cultivars used to differentiate bean common mosaic virus (BCMV) and bean common mosaic necrosis virus (BCMNV) strains, comparisons with a local strain of BCMV (BCMV-SA), and scrological tests with antisera to BCMV and BCMNV indicate that GGSV may serologically react with several BCMV strains but it is not a known strain or serotype of BCMV. Thus, GGSV may be a new guar legume potyvirus.