First Report and Partial Molecular Characterization of a New Begomovirus Associated with Pigeon Pea in Puerto Rico.

Pigeon pea (Cajanus cajan (L.) Millsp.) is an important edible legume crop in Puerto Rico. In late fall 1997, symptoms of a golden mosaic virus were observed in a pigeon pea planting in the municipality of Villalba. The symptoms resembled those incited by the Rhynchosia mosaic virus, a whitefly-transmitted virus, in pigeon pea (1). Tests with the 3F7 antigeminivirus antibody from Agdia (Elkhart, IN) confirmed the presence of a begomovirus in these symptomatic pigeon peas. Extraction of DNA from dried symptomatic foliar tissue was accomplished by the methods described in Rojas et al. (2), and subsequent viral DNA amplification was accomplished with the coat protein (CP) gene polymerase chain reaction primer pair AV494-AC1048 (3). A 550-bp fragment was cloned and sequenced (GenBank Accession No. AY028308). For sequence analysis, the BLAST program at the National Institutes of Health was used. The first match was 91% with the CP gene sequence (Accession No. AF070924) of a begomovirus from Clitoria falcata from Puerto Rico. The next three matches were approximately 86% with a begomovirus (accession no. AF058024) from Macroptilium lathyroides from Puerto Rico, Dicliptera yellow mottle virus (Accession No. AF139168) from Florida, and Tobacco apical stunt virus (Accession No. AF076855) from Mexico. On the basis of sequence analysis of this conserved region of the CP gene, it is concluded that the virus described in this report is a new virus, and thus named Pigeon pea golden mosaic virus. The only sequence for a begomovirus from a Rhynchosia sp. in GenBank is Rhynchosia golden mosaic virus from Honduras (accession no. AF239671). On the basis of sequence comparisons, the virus from pigeon pea is not an isolate of the Honduran Rhynchosia golden mosaic virus. References: (1) J. Bird et al. 1975. Pages 3-25 in: Tropical Diseases of Legumes. J. Bird and K. Maramorosch, eds. Academic Press, NY. (2) M. R. Rojas et al. Plant Dis. 77:340, 1993. (3) S. D. Wyatt and J. K. Brown. Phytopathology. 86:1288, 1996.