A new tobamovirus named tomato brown rugose fruit virus (ToBRFV) overcomes the effect of the Tm-1, Tm-2, and Tm-2 2 resistance genes introgressed from wild Solanum species into cultivated tomato ( Solanum lycopersicum ). Here, we report the isolation and molecular characterization of a spontaneous mutant of ToBRFV that breaks resistance in an unknown genetic background, demonstrated recently in Solanum habrochaites and Solanum peruvianum.
The wild isolate ToBRFV-Tom2-Jo and the mutant ToBRFV-Tom2M-Jo were fully sequenced and compared to each other and to other ToBRFV sequences available in the NCBI GenBank database. Sequence analysis revealed five nucleotide substitutions in the ToBRFV-Tom2M-Jo genome compared to ToBRFV-Tom2-Jo. Two substitutions were located in the movement protein (MP) gene and resulted in amino acid changes in the 30-kDa MP (Phe22 → Asn and Tyr82 → Lys).
These substitutions were not present in any of the previously described ToBRFV isolates. No amino acid changes were found in the 126-kDa and 183-kDa replicase proteins or the 17.5-kDa coat protein. Our data strongly suggest that breaking the newly discovered resistance in wild tomatoes is associated with one or two mutations on the MP gene of ToBRFV.
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Jewehan, Ahmad & Kiemo, Francis & Salem, Nida & Tóth, Zoltán & Salamon, Pál & Szabo, Zoltan. (2022). Isolation and molecular characterization of a tomato brown rugose fruit virus mutant breaking the tobamovirus resistance found in wild Solanum species. Archives of Virology. 10.1007/s00705-022-05438-2.