BEAN GOLDEN MOSAIC GEMINIVIRUS TYPE-II ISOLATES FROM THE DOMINICAN-REPUBLIC AND GUATEMALA - NUCLEOTIDE-SEQUENCES, INFECTIOUS PSEUDORECOMBINANTS, AND PHYLOGENETIC-RELATIONSHIPS

Bean golden mosaic geminivirus (BGMV) causes major losses on beans (Ph aseolus vulgaris) in the tropical and subtropical Americas and the Car ibbean Basin. Infectious DNA-A and -B components of BGMV isolates from the Dominican Republic (BGMV-DR) and Guatemala (BGMVGA) were sequence d, and their genome organizations were similar to those of other white fly-transmitted geminiviruses from the Western Hemisphere. Whiteflies (Bemisia tabaci) transmitted BGMV from beans infected by particle-gun inoculation with clones of BGMV-DR or -GA. Infectious pseudorecombinan ts gave symptoms typical of wild-type infections when mixtures of BGMV -GA DNA-A and BGMV-DR DNA-B were used. Delayed and attenuated symptoms were obtained when mixtures of BGMV-DR DNA-A and BGMV-GA DNA-B were u sed. Phylogenetic analyses using the common region and four open readi ng frames placed 20 geminiviruses in eight clusters for the Western He misphere and at least five clusters for the Eastern Hemisphere viruses . BGMV-DR and -GA are in the BGMV type II cluster with the BGMV isolat e from Puerto Rico. The BGMV type II cluster is clearly distinct from the BGMV type I cluster, which contains the BGMV isolate from Brazil. Bean dwarf mosaic geminivirus is in the Abutilon mosaic virus cluster, and bean calico mosaic geminivirus is in the squash leaf curl geminiv irus cluster. Conserved nucleotide sequences of the common regions of members of these clusters were identified, and the presence of amino a cid motifs with putative functions were identified in the derived amin o acid sequences of the replication-associated proteins of BGMV-DR and -GA. The availability of sequenced, infectious clones of BGMV-DR and -GA provides opportunities for the study of genome functions and for t he engineering of beans for resistance to these viruses.