A single amino acid substitution in movement protein of tomato torrado virus influences ToTV infectivity in Solanum lycopersicum

•Tomato torrado virus-Kra variant (ToTV-Kra-L) is symptomless in tomato.•ToTV-Kra-L is infectious and induces typical symptoms in Nicotiana benthamiana.•ToTV-Kra-L carries a F210L mutation in the movement protein (3A) domain of ToTV RNA2.•F210 (in ToTV) is conserved among all tomato-infecting torradoviruses.

Tomato torrado virus (ToTV), which is a tomato-infecting member of the genus Torradovirus, induces severe systemic necrosis in Solanum lycopersicum cv. Beta Lux as well as leaf malformation and chlorosis in Nicotiana benthamiana. To date, neither the tomato gene conferring resistance to the pathogen nor the ToTV-encoded necrosis determinant have been characterized. We herein revealed that the phenylalanine 210 residue in the movement protein domain encoded by ToTV RNA2 is a necrosis-inducing pathogenicity determinant during tomato infection. Using a ToTV infectious RNA2 clone, we performed site-directed mutagenesis of the phenylalanine 210 residue, confirming its importance during ToTV infection and symptom manifestation in S. lycopersicum cv. Beta Lux, but not in N. benthamiana.