Zoospore development in the oomycetes

Oomycetes cause destructive diseases on both animals and plants. The epidemic spread of oomycete diseases is primarily based on rapid dispersal from host to host by free swimming zoospores. These single-nucleated spores are formed in sporangia and are only released in aqueous environments. Oomycetes are classified in the Kingdom of the Stramenopiles or Chromista, which is comprised of several organisms, including the golden brown algae. The unique shared attribute found in most Stramenopiles is the morphology of the zoospores and especially the structure of their two flagella. They have one tinsel flagellum, and one whiplash flagellum. Only the tinsel flagellum has distinctive flagellar hairs. Zoospore formation can occur within minutes and it is considered one of the fastest developmental processes in any biological system. Once released from the sporangium they are able to exhibit chemotactic responses, electrotaxis, and autotaxis or autoaggregation to target new hosts for infection. Here we discuss the latest discoveries in the development and biology of the oomycete zoospore.