myxogastria

Myxogastria, commonly known as plasmodial slime molds, are a group of eukaryotic organisms within the Amoebozoa. They are characterized by a feeding stage that forms a single, multinucleate mass called a plasmodium, which moves by cytoplasmic streaming and engulfs microorganisms in decaying organic matter.

Habitat and life cycle: They inhabit leaf litter, soil, and decaying wood in moist environments worldwide. Most species begin as haploid cells (myxamoebae) or flagellated cells that feed on bacteria. Under adverse conditions, compatible cells fuse to form a diploid zygote that develops into the plasmodium. The plasmodium grows by cytoplasmic streaming, then differentiates into fruiting bodies (sporangia) that produce spores.

Reproduction and spores: Sporangia release spores that disperse by wind. In many species, spores germinate into new haploid cells, restarting the cycle. Sexual reproduction can also occur through fusion of compatible gametes, followed by meiosis in the spore stage. Some species form resistant structures such as sclerotia under drought or other stress.

Ecology and significance: As decomposers, plasmodial slime molds contribute to nutrient cycling in forest and soil ecosystems. They have long been studied for their unusual life cycle, cellular organization, and, in some life stages, social-like behaviors. Their simple yet dynamic life history makes them a model for research in cell biology and evolution.

Taxonomy and diversity: Myxogastria is a class within Amoebozoa that includes multiple orders and genera, such as Physarales (Physarum), Stemonitales (Stemonitis), and Trichiaceae. The group comprises around 1,000 described species. Advances in molecular phylogenetics have refined their classification, but the plasmodial lifestyle remains a defining trait.