摘要: Phytomyxea comprises two orders: Plasmodiophorida and Phagomyxida. The group is characterized by a unique type of nuclear division, cruciform in which persistent nucleolus aligns parallel to the spindle perpendicularly metaphase plate chromatin. Other major features are intracellular, biotrophic plasmodia as growth forms heterokont, biflagellated zoospores. Members produce environmentally resistant resting spores, have not been observed Economically significant phytomyxids include causal agents clubroot on cabbage other brassicaceous crops powdery scab potato. In addition, several vectors for pathogenic viruses crop plants, including wheat sugar beet.