4 - Epidemiology and Evolution of Fungal Pathogens in Plants and Animals

Abstract

This chapter discusses the main pathogenic fungi parasitizing humans, animals, and plants, and having important consequences on human health or human activities. It discusses the modern molecular tools used for epidemiology and population genetics of fungal pathogens. The two major groups, Ascomycota and Basidiomycota, are the most common causes of invasive fungal infections in humans. Fungal pathogens can cause severe disease in wildlife species and plants. They reduce crop yield and lower product quality by attacking cultivated plants and their products. Our primary food production is at risk due to emerging crop diseases. Epidemics caused by invasive pathogens have been repeatedly reported to alter natural ecosystems. Molecular epidemiologic studies to study fungal pathogens use techniques such as MLST, multilocus strain typing and MLMT, multilocus microsatellite typing. Gene-sequence data from studies using genealogical concordance phylogenetic recognition (GCPSR) can easily be converted to strain sequence types (STs) and stored in web databases. Population genetics is also needed to understand fungal diseases. It has provided important insights for some fungal pathogens on their mating systems, dispersal, and population structure. It offers the opportunity to forecast the emergence of genotypes, populations, or species with detrimental characteristics for human affairs. This chapter reveals that comparative genomic studies in plant pathogenic and symbiotic fungi have brought many insights into the evolution of the pathogenic lifestyle, in particular into the mechanisms of virulence and host adaptations. Regarding epidemiology, it is concluded that molecular methods have much to offer to the study of fungal pathogens, allowing elucidation of ecological and microevolutionary processes. The chapter states that microsatellite markers in particular are very powerful tools and should be more widely used for population studies in fungi, despite the technical challenges of their isolation in this kingdom.