Olpidium bornovanus, a unicellular fungus, is an obligate parasite of plants that reproduces with flagellated, swimming zoospores. A-B. Vegetative unicellular thalli in cucumber root cells. Thalli differentiate into sporangia with zoospores, or into resting spores. C. An empty sporangium, after zoospore release. D. A thick-walled resting spore. E. Zoospores being released from a sporangium, showing the sporangium exit tube (arrowheads). F. A swimming zoospore with a single posterior flagellum. G. An encysted zoospore. Bars: A-E = 10 μm; F,G = 5 μm.
Sekimoto et al. BMC Evolutionary Biology 2011 11:331 doi:10.1186/1471-2148-11-331