Virus Host Jumping Can Be Boosted by Adaptation to a Bridge Plant Species

• Main Authors: Sandra Martínez-Turiño, María Calvo, Leonor Cecilia Bedoya, Mingmin Zhao, Juan Antonio García
• Format: Article
• Language: English
• Published: MDPI AG 2021-04-01
• Series: Microorganisms
• Subjects: host jumping; viral evolution; trade-off; plant virus; RNA virus; potyvirus
• Online Access: https://www.mdpi.com/2076-2607/9/4/805

Understanding biological mechanisms that regulate emergence of viral diseases, in particular those events engaging cross-species pathogens spillover, is becoming increasingly important in virology. Species barrier jumping has been extensively studied in animal viruses, and the critical role of a suitable intermediate host in animal viruses-generated human pandemics is highly topical. However, studies on host jumping involving plant viruses have been focused on shifting intra-species, leaving aside the putative role of “bridge hosts” in facilitating interspecies crossing. Here, we take advantage of several VPg mutants, derived from a chimeric construct of the potyvirus <i>Plum pox virus</i> (PPV), analyzing its differential behaviour in three herbaceous species. Our results showed that two VPg mutations in a <i>Nicotiana clevelandii</i>-adapted virus, emerged during adaptation to the bridge-host <i>Arabidopsis thaliana</i>, drastically prompted partial adaptation to <i>Chenopodium foetidum</i>. Although both changes are expected to facilitate productive interactions with eIF(iso)4E, polymorphims detected in PPV VPg and the three eIF(iso)4E studied, extrapolated to a recent VPg:eIF4E structural model, suggested that two adaptation ways can be operating. Remarkably, we found that VPg mutations driving host-range expansion in two non-related species, not only are not associated with cost trade-off constraints in the original host, but also improve fitness on it.