dictyostelid

Dictyostelids, or social amoebae, are a group of organisms within the Amoebozoa that live as single-celled, bacterivorous amoebae in soil and leaf litter. They form a multicellular fruiting structure in response to starvation, illustrating a transition from unicellular to multicellular organization.

During starvation, cells secrete cyclic AMP (cAMP) as a chemoattractant to coordinate aggregation into a mound and then a migrating slug, which can move toward light or warmth. This collective behavior brings many individual cells into a developmental unit capable of producing a reproductive structure.

The slug differentiates into a fruiting body with a stalk supporting a sorus of dormant spores. Some cells become stalk cells and die to elevate the spores, while others become spores that survive dispersal. This developmental program demonstrates cooperative behavior and cell differentiation, including the formation of distinct prestalk and prespore regions within the structure.

Dictyostelium discoideum is the best-studied species and a model organism for investigating cell motility, chemotaxis, signaling, and multicellularity. Its genome has been sequenced, revealing roughly 12,000–13,000 genes and complex regulatory networks that govern development and differentiation, making it a widely used system in cell and developmental biology.

Taxonomically, dictyostelids reside in the Dictyostelia, within the Amoebozoa. The genus Dictyostelium comprises several species, with D. discoideum being the most prominent in research contexts.