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Abstract
Tobacco thrips, Frankliniella fusca (Hinds), is a major vector of tomato spotted wilt orthotospovirus (TSWV) in peanut of the southeastern United States. TSWV infection in peanut causes the yield-limiting spotted wilt disease. In this study, temporal changes in TSWV accumulation in peanut and TSWV acquisition and inoculation by F. fusca were assessed and detection of TSWV-transmitting thrips on sticky cards was optimized. Results indicated that TSWV transmission varied temporally, and these temporal changes were caused by the percentage of viruliferous thrips and the field inoculum available throughout the cropping season. Resistant cultivars are widely used for TSWV management, and new cultivars with improved resistance can increase the sustainability of TSWV management. However, sources of genetic resistance in cultivated peanut are limited. Related/wild Arachis species are important sources of resistance against TSWV and F. fusca. Experiments were conducted to examine resistance/tolerance against thrips and/or TSWV in 16 wild peanut genotypes. Plausible TSWV resistance in diploid species and tetraploid hybrids was characterized by reduced TSWV infection, virus accumulation and/or thrips damage. Lastly, to explore resistance mechanisms in wild peanuts, transcriptional responses in two diploid species and their hybrid in response to TSWV were compared by gene expression in wild diploids and induced allotetraploids. The changes in gene expression in response to TSWV infection seems to be more pronounced in A. valida accession GK30011 (BB genome) than in A. stenosperma V10309 (AA genome).