second, third, and fourth authors, Centro de Ingeniería Genética y Biotecnología, P.O. Box 6162. La Habana. CP 10600. Cuba. E-mail: email@example.com
First and fifth authors, Instituto de Investigaciones de Sanidad Vegetal, Cuba
sixth author, Laboratorio Provincial de Sanidad Vegetal de Holguín
seventh author, Centro Internacional de Agricultura Tropical, Colombia
In Cuba, the emergence of bean golden mosaic was associated with high populations of Bemisia tabaci in common bean (Phaseolus vulgaris L.) plantings in the 1970s (1). During the last two decades, the disease has caused significant economic losses, forcing some growers to abandon bean production. In Holguín, one of the main bean producing provinces of the country, about 2,000 ha of beans were abandoned in 1991 due to the high incidence of this whitefly-transmitted virus. At that time, yield losses associated with this disease reached 90 to 100% in farmer's fields. In spite of various control measures, the disease affected 33, 28, and 6.5% of the total area planted in Cuba to common bean in 1990, 1992, and 1996, respectively. For this investigation, common bean leaves showing systemic yellowing symptoms were collected in fields located in the provinces of Havana, Matanzas, and Holguín during 1998-1999. Sap and total DNA leaf extracts were used to inoculate healthy bean plants by manual and biolistic procedures, respectively. Characteristic yellowing symptoms were more efficiently reproduced using a particle gun device than by manual inoculation (18/20 plants and 5/20 plants, respectively, for a Holguín virus isolate). DNA extracts were further analyzed by polymerase chain reaction using two degenerate primer sets: PAL1v1978-PAR1c715 and PAL1c1960-PAR1v722 (2). Fragments of approximately 1.4 and 1.2 kb were amplified and cloned. Restriction fragment length polymorphism analysis of the cloned 1.4-kb fragments was performed with BglII, HincII, SalI, EcoRI, PstI, and XbaI, indicating that selected isolates from the three Cuban provinces shared identical restriction patterns. The nucleotide sequence obtained from two clones of a virus isolate from Holguín, was compared to sequences available for other begomoviruses using BLAST. The Cuban isolate shared up to 94% nt sequence identity with various strains of Bean golden yellow mosaic virus (BGYMV) in the first 250 nt of the rep gene. For the common region (CR), scores were 93% for BGYMV-GA (Guatemala), 92% for BGYMV-MX (southern Mexico) and BGYMV-PR (Puerto Rico), and 91% for BGYMV-DR (Dominican Republic). The iterative sequence ATGGAG was identified in the CR of the Cuban BGYMV isolate, as reported for other BGYMV isolates. Finally, the Cuban begomovirus, hereafter referred to as BGYMV-CU, shared nt and aa sequence identities of 94 and 100%, respectively, with the coat protein gene of BGYMV-MX. We conclude that the begomovirus isolated from mosaic-affected common bean plants in the province of Holguín is a member of the Mesoamerican BGYMV group (3).
References: (1) N. Blanco and C. Bencomo. Cienc. Agric. 2:39, 1978. (2) M. R. Rojas et al. Plant Dis. 77:340, 1993. (3) Morales and Anderson, Arch. Virol. 146:415, 2001.