Fungal cannons: explosive spore discharge
Spores the most recognizable of fungal cells are produced in prolific quantities and sent forth to colonize fresh substrates. Members of the Kingdom Fungi disperse their spores through air and water using a variety of techniques. The members of the phylum Ascomycota, which constitute nearly 75% of all described fungi, produce their sexual spores (ascospores) in tubular sacs called asci; some asci act like small water cannons and expel the spores into the air. Shooting asci have evolved to stretch upward and thrust the spores through a pore in the top of the sac. The mechanism has long been thought to be driven by turgor pressure within the extending ascus. Dispersal of spores by forcible discharge is critical for the dissemination of nonmotile propagules of many fungal plant disease organisms as well as many saprophytic fungi. Despite the prevalence of this dispersal mechanism among economically important fungi, the mechanism has not been well studied in any fungus. In this review, the structure and function of the shooting ascus is explored.
Interestingly, despite the fact that several known human pathogens fall into the Pezizomycotina, there are no known human pathogens that rely on ascospore discharge as an epidemiological component. There is no obvious reason for this disparity. It may be artificial due to the very small number of known fungal human pathogens (about 150 in total) when compared with fungal plant pathogens (more than 8000 species).
Fungal cannons: explosive spore discharge in the Ascomycota.
FEMS Microbiology Letters
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