Ocorrência de vírus em lavouras de alface (Lactuca sativa L.) no sul de Minas Gerais

Abstract

Lettuce (Lactuca sativa) can be found growing all over the world and is the Brazil’s most consumed vegetable. The viral diseases are considered a limiting factor in the production of this crop, since it can affect their leaves, devaluing and making them commercially useless. This study was carried out aiming to determine which viruses are prevalent in some commercial areas located in southern region of Minas Gerais state, Brazil. Samples were collected in crops located in Lavras, Nepomuceno, Santana da Vargem, Boa Esperança, Três Corações, Três Pontas, Varginha and São Gonçalo do Sapucaí. Part of the collected material was mechanically inoculated in indicators plants; part was desiccated and stored for future studies and the remainder was submitted to RT-PCR. The primers used were specific for the mains viruses that infect lettuce: Lettuce mosaic virus (LMV), Lettuce mottle virus (LeMoV), Lettuce big-vein associated virus (LBVaV), Mirafiori lettuce big-vein ophiovirus (MLBVV), Tospovirus genus and Tospovirus species specific for Groundnut ringspot tospovirus (GRSV), Tomato chlorotic spot tospovirus (TCSV), Chrysanthemum stem necrosis virus (CSNV) and Tomato spotted wilt tospovirus (TSWV). The viruses found in the field were LMV, LeMoV and Tospovirus TCSV and GRSV, with higher occurrence of LMV and TCSV. The molecular characterization of the Brazilian isolates confirmed the identity of the Tospovirus TCSV and GRSV species.