Fungi Infecting Plants and Animals: Killers, Non-Killers, and Cell Death

Fungi occupy every inhabitable ecological niche on earth [1].Environmental requirements vary, from species with very specificones to species that can live under a broad range of conditions.Pathogenic fungi are those species that occupy and derivenutrients from living organisms. Some fungal pathogens com-pletely depend on their host, while others can prosper in additionalenvironments. Fungal host restrictions also vary considerably,from single-host-specific species to broad-host-range pathogensthat can cause disease in a large number of different hosts. Anextreme example is the genus Fusarium, with species that causediseases in thousands of plant species as well as in animals,including humans [2]. Thus, while plants and animals present verydifferent environments (hosts in the case of pathogens), the fungithat attack them are phylogenetically closely related. The samepathogenicity principles might therefore be used by animal andplant pathogens, albeit with some variation.