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 specific ones to species that can live under a broad range of conditions. Pathogenic fungi are those species that occupy and derive nutrients from living organisms. Some fungal pathogens completely depend on their host, while others can prosper in additional environments. Fungal host restrictions also vary considerably, from single-host-specific species to broad-host-range pathogens that can cause disease in a large number of different hosts. An extreme example is the genus Fusarium, with species that cause diseases in thousands of plant species as well as in animals, including humans [2]. Thus, while plants and animals present very different environments (hosts in the case of pathogens), the fungi that attack them are phylogenetically closely related. The same pathogenicity principles might therefore be used by animal and plant pathogens, albeit with some variation.