Conhecendo a população de Bemisia tabaci do Rio Grande do Sul e o primeiro relato da ocorrência de Tomato severe rugose virus (ToSRV) em pepino

Abstract

Over the past 20 years, the emergence of diseases caused by begomoviruses has been causing serious problems in a variety of horticultural crops in various parts of the world. In addition to climatic factors and changes in cultivation modes, the emergence of these viruses is related to the increase and prevalence of insect vector, whitefly (Bemisia tabaci). The aim of this work was to know the population of B. tabaci of Rio Grande do Sul and molecularly characterize a begomovirus isolate associated with cucumber. In order to know the population of B. tabaci, collections were realized in several regions of the state. The total DNA extraction was realized individually for each adult collected, after the PCR was performed to identify the whitefly species. For the 51 individuals who had positive results for B. tabaci was realized digestion with the restriction enzyme TaqI, in order to identify the species of the complex B. tabaci. Three species belonging to this complex were found: Middle East-Asia Minor 1 (MEAM1), New World (NW) and Mediterranean (MED). The predominant species was MEAM1 found in the cities of Bom Princípio, Caxias do Sul and Feliz, followed by NW species found in Cruzeiro do Sul and Lajeado. For the molecular characterization of begomovirus associated with cucumber, plants were collected where the white flies were found. Total DNA extraction from 35 plant samples was performed and submitted to PCR. Of 35 samples, only 7 presented showed positive results for begomovirus. Samples that showed a positive result were used in amplification by RCA and digested with restriction enzymes. For cloning, only the cucumber sample was used. After the sequence analysis the presence of Tomato severe rugose virus (ToSRV) was verified. This is the first report of ToSRV infecting cucumber.