sporulation

Sporulation is a biological process by which certain organisms form spores, durable and dormant units that enable survival through periods of environmental stress. The term covers endospore formation in bacteria as well as sporogenesis in fungi and plants.

In bacteria, sporulation typically follows nutrient limitation. A cell undergoes asymmetric division to produce a forespore that is gradually engulfed and surrounded by protective layers, forming an endospore. The core dehydrates, and stabilizing molecules such as small acid-soluble proteins and calcium dipicolinate protect DNA. Endospores are highly resistant to heat, desiccation, and chemicals, allowing persistence in harsh conditions. Germination occurs when conditions become favorable, and a vegetative cell resumes growth.

In fungi, sporogenesis produces spores for dispersal or propagation. Spores may form by mitosis (conidia, blastospores) on structures like conidiophores or sporangia, or by meiosis (ascospores, basidiospores) within fruiting bodies. Spores are often adapted for long-range dispersal and environmental resilience, supporting life-cycle completion across diverse habitats.

In plants and many algae, sporogenesis is part of the life cycle’s alternation of generations. The sporophyte produces haploid spores by meiosis, which germinate into haploid gametophytes. In seed plants, this includes microspores and megaspores that give rise to pollen and the female gametophyte tissues.

Applications and implications: understanding sporulation informs sterilization and disease control, as endospores resist many harsh treatments. Studying sporulation illuminates evolutionary strategies for survival, persistence, and dispersal across ecosystems.