Epsilon Archive for Student Projects

Abstract

Every year begomovirus infections cause severe constraints to the tomato production in Nicaragua. Extensive yield losses are followed by large economical losses, both for the country and the single farmer. During recent years the use of begomovirus resistant or tolerant tomato cultivars has increased in Nicaragua as an effort to improve yields. Still, begomovirus infection is a large threat to the tomato production. Therefore, ongoing work in Nicaragua is focusing on finding new, better, begomovirus tolerant or resistant tomato cultivars. This study aims to be a part of this work, by investigating the current prevalence and diversity of begomoviruses in the resistant tomato variety Shanty. Nicaraguan tomato plants of the variety Shanty were collected from four geographical locations around Nicaragua (Sebaco, CNIAB (close to Managua), Las Playitas, Tecolostote). The collected samples were investigated for begomovirus infection using polymerase chain reaction (PCR) and universal begomovirus primers. Infection was confirmed at all locations where plants with clear symptoms of infection had been collected. Infection was also detected in plants, which had been collected without any visible symptoms of begomovirus infections. Rolling circle amplification (RCA) produced a suitable product for restriction analysis in six of the begomovirus positive samples. Restriction analysis with the three restriction enzymes EcoRI, SalI and HpaII, showed mixed infection (more than one begomovirus species present in the tomato plant) in ~80% of the analysed samples. The results showed that the most common tomato producing areas in Nicaragua (Sebaco, CNIAB, Las Playitas, Tecolostote) still are heavily exposed to begomovirus infections and that mixed viral infections are relatively common in these regions.