Fungi of the phylum Zygomycota are almost entirely terrestrial and live on dead plant and animal material. Zygotes are able to reproduce both asexually and sexually. In the zygote asexual reproductive cycle, spores germinate into hyphae and and produce haploid spores from sporangium.
Sexual reproduction of zygotes requires the conjugation of plus and minus hyphal strands. The temporary uniting of the plus and minus strands during which the strands exchange genetic material causes each strand to produce a gametangium. The nuclei of the plus and minus strands then fuse in fertilization, creating a diploid zygospore. The zygospore undergoes meiosis to produce four haploid nuclei, out of which only one is functional and the other three degenerate. The zygospore is able to withstand harsh conditions and germinates into hyphae, thus beginning the asexual stage.
Ascomycota, also known as sac fungi, have both sexual and asexual reproductive stages. In the asexual stage, conidia form on the fungi’s conidiophores, special aerial hyphae. Spores then form on the conidia and are dispersed away from the parent by the wind.
Ascomycota sexually reproduce by first fusing the hyphae of different mating strains. Mitotic nuclear division leads to multiple nuclei in the ascogonium and anthoridium (male and female gametangia, respectively), then the nuclei are transferred to the ascogonium. The haploid nuclei from two different strains are now in the ascogonium, which divides cytokinetically with walls between the nuclei, thus creating dikaryotic cells. These dikaryotic cells divide via mitosis and the dikaryotic and sterile hyphae form cuplike structures called ascocarps containing special cells called asci, or sacs. The fusing of two nuclei in the ascus forms a zygote, which undergoes meiosis to form four haploid ascospores. Each ascospore undergoes mitosis to form two ascospores, thus forming eight ascospores in total. The spores are then released and germinate into new hyphae.
Basidiomycota form mushrooms as their fruiting bodies, called basidiocarps, to reproduce. Fungi in phylum Basidiomycota reproduce sexually. Different mating strains meet underground and the cells fuse, however, the nuclei join together without fusing. Dikaryotic hyphae then form and grow into basidiocarps. A basidiocarp is a structure consisting of a stalk, which supports a cap with gills on the underside. The basidiocarp gills give rise to stalks called basidia. Haploid nuclei fuse at the tips of the basidium. each basidium then undergoes meiosis and forms four basidiospores, which are released into the environment and germinate into new hyphae.