Evolutionary and ecological links between plant and fungal viruses.

Contents Summary I. Introduction II. Lineages shared by plant and fungal viruses III. Virus transmission between plants and fungi IV. Additional plant virus families identified in fungi by metagenomics Acknowledgements References SUMMARY: Plants and microorganisms have been interacting in both positive and negative ways for millions of years. They are also frequently infected with viruses that can have positive or negative impacts. A majority of virus families with members that infect fungi have counterparts that infect plants, and in some cases the phylogenetic analyses of these virus families indicate transmission between the plant and fungal kingdoms. These similarities reflect the host relationships; fungi are evolutionarily more closely related to animals than to plants but share very few viral signatures with animal viruses. The details of several of these interactions are described, and the evolutionary implications of viral cross-kingdom interactions and horizontal gene transfer are proposed.