Viruses that Affect Phenotype and Fitness of Fungi

Mycoviruses are the viruses that infect fungi and the unrelated stramenopiles such as oomycetes that have morphologies and lifestyles similar to fungi. Our knowledge of mycoviruses and their effects on the biology of their hosts has exploded in recent years. Although the field only started to mature in the 1980s and 1990s, advances in technology coupled with the promise of mycoviruses for biological control of fungi pathogenic to plants, animals, and humans led to increased attention and dedicated research. Mycoviruses are now classified within at least 16 virus families, and that number grows continually as new viruses that do not fit within the current taxonomy are described. This chapter highlights some of the most important fungal virus systems, and some of the advances in our understanding of mycoviruses, especially in the context of their effects on host biology and fitness.