Studies on Geminiviridae on bean in Brazil
Bean golden mosaic begomovirus (BGMV - EPPO A1 quarantine pest) was first described in Brazil. Initially the disease caused minor losses but during the 1970s, it became a major constraint for bean production throughout Brazil, Central America, Caribbean basin and Florida (US). Recent studies on molecular properties and mechanical transmission have concluded that BGMV from Brazil (BGMV-BZ) was distinct from BGMV from Dominican Republic, Guatemala and Puerto Rico. Molecular studies were carried out in Brazil on the variability of BGMV isolates. Samples of plants (beans (Phaseolus vulgaris), lima beans (P. lunatus) and a weed Leonurus sibiricus) showing symptoms were collected from the main bean-producing areas in Brazil and their genotypic variability was assessed by using molecular techniques (PCR, comparison of DNA sequences). Results showed that all isolates from P. vulgaris (collected from Goiás, Mato Grosso do Sul, Minas Gerais, Paraná, Pernambuco*, Rio Grande do Sul, São Paulo) were similar to BGMV-BZ. The authors noted that this lack of variability among the viral fragments studied could indicate that BGMV present in these main bean-producing areas can be considered as a single population.
This may have implications for breeding resistant bean cultivars. The sample from P. lunatus presented a distinct viral sequence, and it was considered that this represented a new geminivirus named lima bean golden mosaic virus. A mixed infection with abutilon mosaic begomovirus was also found in a single bean sample from São Paulo. Finally, the virus isolated from the weed Leonurus sibiricus was considered as a distinct virus named leonurus mosaic virus.
*New detailed record
Faria, J.C.; Maxwell, D.P. (1999) Variability in geminivirus isolates associated with Phaseolus spp. in Brazil.
Phytopathology, 89(3), 262-268.