Members of the same sex of a pathogenic fungal species can mate and produce offspring, scientists report in the April 21 issue of Nature. The finding suggests for the first time that the fungus has developed a novel type of sexual cycle, according to senior author Joseph Heitman at Duke University in Durham, NC.
Cryptococcus neoformans causes life-threatening meningoencephalitis in immunocompromised patients. The fungus has two sexes, alpha and a, but the vast majority ofC. neoformans isolates seen clinically and in the environment are alpha, leaving them with apparently few chances to mate. "Normally when you have sexually reproducing organisms, you find both sexes in roughly equal numbers," Heitman told The Scientist.
During mating, C. neoformans develops filaments and spores. Haploid alpha strains can also grow filaments and spores in a process known as fruiting, which researchers thought was asexual and mitotic. To see if diploidization occurred during fruiting, Heitman ...