DIFFERENTIATION OF BEAN-INFECTING GEMINIVIRUSES BY NUCLEIC-ACID HYBRIDIZATION PROBES AND ASPECTS OF BEAN GOLDEN MOSAIC IN BRAZIL

A bean golden mosaic geminiviral isolate from Goiania, Goias, Brazil (BGMV-BZ), was determined to be transmitted by whiteflies and induced golden mosaic symptoms and diagnostic geminiviral inclusion bodies and ultrastructural abnormalities in infected bean leaves. In contrast to BGMV isolates from Central America and the Caribbean, BGMV-BZ could not be sap-transmitted to beans. Cloned geminiviral DNA components were used as DNA probes for the rapid and specific detection of BGMV-BZ and three sap-transmissible bean-infecting geminiviral isolates-BGMV from Guatemala (BGMV-GA) and the Dominican Republic (BGMV-DR) and bean dwarf mosaic geminivirus from Columbia (BDMV-CO). A general DNA probe detected all four viral isolates, whereas specific probes detected BGMV-BZ, BDMV, or BGMV-GA and BGMV-DR. Nucleic acid dot and squash blot methods were used to prepare samples for hybridization, and the dot blot method was used to determine relative differences in viral nucleic acid titers in infected bean leaves. The general and specific probes were employed to study the variability of BGMV isolates and potential weed reservoirs of geminiviruses in the Dominican Republic.