Exploring the weed host range of resistance-breaking variants of tomato spotted wilt orthotospovirus (TSWV) across life cycles in Türkiye

Tomato spotted wilt orthotospovirus (TSWV) is destroying tomato and pepper resistance all over the world, including Antalya (Türkiye). Two greenhouses that show infection of TSWV in the Serik (coastal) and Elmali (highland) areas were chosen for research between 2019 and 2021 to better understand the disease's life cycle. During the surveys, we focused on weed hosts to better understand TSWV disease's cycle. TSWV infection was determined in 58 peppers, 34 tomatoes, 270 weeds, and 20 other vegetable samples. Weed samples revealed essentially no symptoms, however, grown plants showed classic TSWV symptoms. The Asteraceae family had the highest infection rate among infected weeds, followed by weed species from the Poaceae and Solanaceae families. In addition, to determine the viral strain in the infected plant samples, qRT-PCR and Melt-curve analysis were done using a specially designed primer pair for the study. This primer identifies the point mutation on the NSm-movement protein in the viral genome's medium segment. The non-resistance breaking isolate of TSWV was included in the optimisation studies to evaluate differences between the two isolates at two thermal melting values established by this comparison. These findings demonstrated that the kits, procedures, and primers employed in this investigation can serve as a quick and reliable diagnostic tool for identifying TSWV isolates and that weeds are a key intermediate source for new TSWV infection, as confirmed by sequence data.