Effects of crop viruses on wild plants

Abstract

Global land conversion and intensification of agriculture mean that remnant native plant populations are increasingly exposed to crop viruses. What are the consequences for wild plants? In natural unmanaged systems, the key consideration is how crop virus infection influences plant fitness. Field studies of virus effects on wild plant fitness are scant. Approaches include (i) observational studies, (ii) studies of experimental plants with natural infection, and (iii) studies of experimental plants with experimental infection, with most studies focused on viruses in the Luteoviridae and Potyviridae families. Fitness effects documented are largely neutral to negative. Crop virus influence on wild plants merits attention in ecological conservation and restoration.

Mixed Infections of Four Viruses, the Incidence and Phylogenetic Relationships of Sweet Potato Chlorotic Fleck Virus (Betaflexiviridae) Isolates in Wild Species and Sweetpotatoes in Uganda and Evidence of Distinct Isolates in East Africa

“…However, cross-protection between any of the virus species in our study is unlikely, because it requires high sequence homology [81]. Therefore, the most probable explanation of our observed low incidences of mixed infections may be inefficient vector transmission of viruses between the wild plants or between cultivated and wild plants [31] and/or high levels of virus resistance in wild species preventing infection or keeping virus titers at undetectable levels [12, 82]. Furthermore, synergistic or additive effects of multiple virus infections causing severe disease could have eliminated co-infected plants [1–2, 5, 83–86].…”

“…Furthermore, synergistic or additive effects of multiple virus infections causing severe disease could have eliminated co-infected plants [1–2, 5, 83–86]. These effects can vary among populations [12, 87, 88], species [89] and environments [75, 90, 91]. …”

“…This may in part be due to the fact that viral infections in wild plants are often symptomless, even when the same infection may have obvious symptoms in cultivated plants [8–10]. Whether the same virus strains can infect wild and cultivated plants, but are better adapted to wild plants and hence cause no symptoms, is an issue requiring further study [11, 12]. The geospatial distribution and genetic variability of viruses in wild species is also poorly understood [13, 14].…”

Evidence of Varroa-mediated deformed wing virus spillover in Hawaii

“…Pathogens have been repeatedly shown to jump between species (Levitt et al, 2013;Li et al, 2011;Malmstrom and Alexander, 2016) and the Deformed Wing Virus (Iflaviridae; DWV) affecting honey bees is no exception (Villalobos, 2016). Recent molecular studies have shown that the DWV may have co-evolved with the European honey bee (Apis mellifera), and the original virus may have been a low prevalence pathogen with many variants and low virulence (Martin et al, 2012;Wilfert et al, 2016).…”

Overlooking the smallest matter: viruses impact biological invasions

“…SIV in chimpanzees described in Rudicell et al 2010). Growing evidence suggests that crop viruses can reduce fitness of both native and exotic plants in a number of ways (Malmstrom & Alexander 2016). Thousands of examples exist of viruses infecting crops and invertebrates that remained undetected until they were opportunistically sequenced, many of which are only distantly related to previously identified viruses (Roossinck et al 2010;Shi et al 2016).…”