Comparative host reactions and Frankliniella occidentalis transmission of different isolates of tomato spotted wilt tospovirus from Spain

The abilities of different isolates of tomato spotted wilt tospovirus (TSWV) collected from northeastern and eastern Spain to infect 10 host species, and to be acquired and transmitted by the western flower thrips (WFT), Frankliniella occidentalis were compared. Two isolates of TSWV from a single source plant could be separated according to the different type of local lesions they induced in Nicotiana glutinosa. Host ranges of the studied TSWV isolates were very similar, but differences were found in the symptoms induced and in their capacity to infect specific hosts systemically. Lycopersicon esculentum and Datura stramonium were evaluated for their potential as virus acquisition host species. The proportion of transmitter adult thrips obtained from WET larvae fed on L. esculentum was greater than from D. stramonium. No differences were detected between TSWV isolates in their ability to be acquired and transmitted by WET. No evidence was obtained of alterations in TSWV particles which could affect WET transmissibility due to the repeated mechanical transfers used to clone the isolates. Our findings do not support the existence of pathological effects of TSWV on WFT.