Necessary for the efficient intracellular multiplication of tobamoviruses, probably being a membrane anchor promoting the formation of the replication complex. Constituent of tobamovirus replication complex. Interacts with TOM2A and with the helicase domain of tobamovirus-encoded replication proteins. Reduced efficiency of intracellular multiplication of tobamoviruses (e.g. TMV-L, ToMV, PMMoV, and TMGMV), characterized by a reduced accumulation of viral coat protein (CP) and reduced amplification of TMV-related RNAs. TOM1 inhibition via RNA interference constitutes a useful method for generating tobamovirus-resistant plants. Belongs to the plant tobamovirus multiplication TOM1 protein family.