Tobamovirus spread and diversity in Anthropocene

The term “anthropocene” (Crutzen, 2002) refers to our current geological epoch and illustrates the manifold influences of human existence and actions on geology and evolution. Ornamentals are a true anthropogenic product solely manufactured to please the eye of the beholder. They are produced and traded all over the globe thus opening gateways for viruses. We investigated consequences of anthropogenic impact on virus spread and diversity in ornamentals. We focused on Tobamoviruses that are mechanically transmitted and are lacking a true natural vector. Our study spanned the period from 2000 to 2016 and identified Tobamovirus infections in host plants belonging to 15 different plant families. The ten identified virus species belonged mostly to Tobamovirus subgroup 1. In Solanaceae as well as in Cactaceae members of both Tobamovirus subgroup 1 and 3 were present. Different patterns of virus-host plant associations seem to exist when comparing members of both virus subgroups. Phylogenetic analysis of a partially sequenced Tobamovirus isolated from Hoya, Asclepiadaceae, in 2014 indicates the emergence of a new Tobamovirus species positioned separately from known viruses of the subgroup 3 cluster. Similar evidence has been reported independently from Florida (Schubert and Davison, 2012; Adkins et al., 2016) indicating manmediated global spread of this virus.