Community Ecology of Plant Viruses

Abstract

The ecology of plant viruses has been little studied, particularly in natu- ral ecosystems where symptoms often go unnoticed. Interactions between a plant virus and its host plant are embedded in a broader community of species, many of which can influence the dynamics of both virus and plant. Plant viruses tend to have a limited number of effective vectors, and vector population dynamics, host preference, and movement have a strong influence on virus ecology. Vector dynamics and behavior are strongly influenced by the diversity and structure of the plant community. Ecological interactions between viruses within a host, such as cross-protection, mutual suppression, or competitive exclusion, also impact virus populations. The potential for linked disease and community dynamics is illustrated by experiments that reveal community-shaping apparent competition between plants, resulting from the spillover of plant viruses from reservoir hosts to less susceptible hosts. Moreover, virus suppression of otherwise dominant plant species can have significant consequences in plant communities. Recent studies on the role of viruses in plant invasions suggest that landscape-level changes have resulted from the interactions of viruses and hosts within a community context that includes competing plant species, reservoir hosts, herbivores, and microbial symbionts of plants. As ecological research on plant viruses in natural ecosystems increases, we are likely to see more examples of strong impacts of viruses on the structure of plant communities.