Co-divergence and host-switching in the evolution of tobamoviruses

Abstract

The proposed phylogenetic structure of the genus Tobamovirus supports the idea that these viruses have codiverged with their hosts since radiation of the hosts from a common ancestor. The determinations of genome sequence for two strains of Passion fruit mosaic virus (PafMV), a tobamovirus from plants of the family Passifloraceae (order Malpighiales) from which only one other tobamovirus (Maracuja mosaic virus; MarMV) has been characterized, combined with the development of Bayesian analysis methods for phylogenetic inference, provided an opportunity to reassess the co-divergence hypothesis. The sequence of one PafMV strain, PfaMV-TGP, was discovered during a survey of plants of the Tallgrass Prairie Preserve for their virus content. Its nucleotides are only 73 % identical to those of MarMV. A conserved ORF not found in other tobamovirus genomes, and encoding a cysteine-rich protein, was found in MarMV and both PafMV strains. Phylogenetic tree construction, using an alignment of the nucleotide sequences of PafMV-TGP and other tobamoviruses resulted in a major clade containing isolates exclusively from rosid plants. Asterid-derived viruses were exclusively found in a second major clade that also contained an orchid-derived tobamovirus and tobamoviruses infecting plants of the order Brassicales. With a few exceptions, calibrating the virus tree with dates of host divergence at two points resulted in predictions of divergence times of family specific tobamovirus clades that were consistent with the times of divergence of the host plant orders.

Yellow tailflower mild mottle virus and Pelargonium zonate spot virus co‐infect a wild plant of red‐striped tailflower in Australia

“…The two isolates of YTMMV tested are genetically close, yet a comparison of symptom induction revealed small differences in virulence on solanaceous hosts, notably on petunia and black nightshade plants where symptoms were consistently more severe upon infection with YTMMV‐Cervantes. The detection of YTMMV‐Cervantes in inoculated leaves of Chinese cabbage was surprising, as solanaceous‐infecting tobamoviruses have not been recorded infecting brassicas (Stobbe et al ., ). The RT‐PCR assay result was robust and consistent in all Chinese cabbage samples tested.…”

The community ecology of pathogens: coinfection, coexistence and community composition

“…the host). For example, strong congruence of host and parasite phylogenies has revealed some patterns of cospeciation in plant-fungus, plant-virus, and primate-virus systems (Giraud et al 2008;Stobbe et al 2012).…”

A Natural Reservoir and Transmission Vector of Grapevine Vein Clearing Virus

“…GVCV is considered a recently emerging badnavirus in cultivated grapevines (Zhang et al 2011). Emergence of viruses in crops generally begins with migration of viral isolates from a wild reservoir to a cultivated plant (Fraile et al 2017;Jones and Coutts 2015;Stobbe et al 2012;Tugume et al 2010Tugume et al , 2016Vincent et al 2014;Wren et al 2006). In the interface of wild plants and cultivated crops, emerging viruses expand the host range across plant species of different genera and families owing to ecosystem alterations and viral evolution (Bhat Roossinck and García-Arenal 2015).…”