Incidence and symptomatology of orthotospoviruses infecting horticultural crops in Mexico

Abstract

Mexico is a leading exporter of horticultural products, with agriculture representing a significant portion of the country's annual economic value. Viral diseases in crops are frequently overlooked, despite their potential to cause severe damage. This work aims to assess the presence and impact of viruses in tomatoes, bell peppers, and lettuce, particularly by those viral agents belonging to the genus Orthotospovirus. Despite the importance of tomatoes in Mexico, limited research has addressed the incidence of orthotospoviruses in their production. Consequently, field surveys were conducted in major horticultural regions of Mexico, where symptomatic and asymptomatic tomato plants were sampled and tested for Orthotospovirus infection, including tomato spot wilt virus (TSWV, Orthotospovirus tomatomaculae), Impatiens necrotic virus (INSV, Orthotospovirus impatiensnecromaculae), ground ring spot virus (GRSV, Orthotospovirus arachianuli), tomato chlorotic spot virus (TCSV, Orthotospovirus tomatoflavi), watermelon silver mottle virus (WSMoV, Orthotospovirus citrullomaculosi) and melon yellow spot virus (MYSV, Orthotospovirus meloflavi) using molecular diagnostics. Likewise, the prevalence of INSV in lettuce was determined through ImmunoStrips, reverse transcription PCR (RT-PCR), and sequence analysis, representing the first identification of INSV in the Bajio region. Another critical aspect of this work includes cross-infection dynamics in bell peppers. Using high-throughput sequencing (HTS), a natural mixed infection by INSV and tomato brown rugose fruit virus (ToBRFV, Tobamovirus fructirugosum) was discovered, which may have implications for the pathogen-host interaction. Overall, the results of this study will contribute to understanding the distribution and economic impact of orthotospoviruses in Mexico, as well as their interactions with other plant viruses. Finally, this research seeks to increase awareness among growers and stakeholders about the risks these viruses pose to horticultural production in Mexico and highlights the importance of disease surveillance and management strategies.