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Outbreak of Groundnut ringspot virus, genus Orthotospovirus, in peanut fields in Argentina

Soledad de Breuil: Instituto de Patología Vegetal (IPAVE), CIAP - INTA

<div>Argentina is one of world's leading exporters of peanuts (<em>Arachis hypogaea</em> L.), with the major production area located in the center of the country. During the 2015/2016 growing season, severe outbreaks of a tospovirus-like disease occurred in commercial peanut fields. The aim of this work was to determine the prevalence and geographical distribution of the disease and perform molecular studies of the etiological agent. Diseased peanut plants were observed in 30 of 80 fields surveyed, located in the north-central region of the peanut-growing area. In DAS-ELISA, all samples collected from symptomatic plants reacted strongly with antisera to Groundnut ringspot virus/Tomato chlorotic spot virus (GRSV/TCSV) (Agdia) and Tomato spotted wilt virus (TSWV) (Bioreba). Total RNA was extracted from ELISA-positive tissues and RT-PCR was performed with primers for conserved regions of the GRSV, TCSV and TSWV nucleoprotein (<em>N</em>) genes. PCR amplicons were digested with the <em>Hinc</em>II and <em>Bst</em>NI enzymes and the restriction patterns agreed with those corresponding to GRSV. This result was confirmed by RT-PCR, using specific primers for GRSV <em>N</em> gene, followed by sequencing of the ~800-bp amplified fragments, which shared ≥ 97% nucleotide sequence identity with the Argentine isolate GRSV-AR (KT972594). Our study highlights the importance of understanding the factors that lead to epidemics caused by GRSV and current research is focused on thrips vector dynamics.</div>