ABSTRACT
Three lower eukaryotic microorganisms (Plasmodiophora brassicae, Labyrinthula zosterae, and Synchytrium macrosporum) represent important pathogens of agricultural, aquatic, grassland, wetland, and woodland species of plants. The phylogeny (evolution of organisms over time) and taxonomy (classification of living organisms) of L. zosterae, P. brassicae, and S. macrosporum will be discussed in relation to their importance in plant pathology.
