PLASMODIOPHOROMYCETES

class of plant parasites in the division Eumycota of the kingdom Mycota (fungi) and referred to as endoparasitic slime molds. Some authors assign them to the kingdom Protista. The class contains a single order, Plasmodiophorales, a single family, Plasmodiophoraceae, and nine genera, the most important of which are Plasmodiophora and Spongospora. All members are obligate parasites of algae, fungi, or higher plants, causing cell enlargement, especially of the roots. They are distinguished by the production of motile cells (zoospores) with two unequal anterior whiplike threads (flagella). Plasmodiophora brassicae causes clubroot of cabbage and related plants. Spongospora subterranea causes powdery scab of potato.