Zoosporen

Zoosporen, or zoospores, are motile asexual spores produced by certain fungi, oomycetes (water molds), algae, and other protists. They develop inside specialized spore-bearing cells called zoosporangia and are released when the sporangium opens. Zoospores are typically adapted for aquatic dispersal and often possess two flagella of different types, enabling rapid movement in water.

Most zoospores are produced by mitosis within the sporangium (zoosporogenesis) and are genetically identical to the parent organism. After release, they swim using their flagella to locate a suitable substrate or host. Upon encountering a surface, they encyst and germinate, giving rise to a new thallus or infection unit, depending on the species.

In ecological terms, zoospores support rapid colonization of new habitats and play a crucial role in the life cycles of many pathogens, notably some oomycetes such as Phytophthora and Pythium that cause plant diseases. They also occur in chytrids, where zoospore mobility drives reproduction in aquatic or moist environments.

Because of their role in disease and ecology, zoospores are a focus of study in plant pathology, microbiology, and phycology.