Development of the zoosporangia of Synchytrium endobioticum, the causal agent of potato wart disease.

An ultrastructural study of zoosporangium development of Synchytrium, endobioticum (Schilb.) Perc. is presented. Emphasis is placed on the location of the parasitic fungal thallus in the potato host cell, on the specific location of organelles in relation to the developing zoosporangial wall, and on the host cell reaction to the fungal infection. The cytoplasmic organization of the individual sporangia after division of the zoosporangium into a sorus of sporangia is characterized by numerous similarly sized nuclei, well developed dictyosomes, and the presence of many lipid bodies of variable size. Cytoplasmic microtubules are observed to flare out from the functional kinetosome both before and after zoospore cleavage. The ultrastructural details of zoosporangium development are used to revaluate the life cycle of S. endobioticum as described from light microscopic observations made early in the century ( Curtis 1921; Köhler 1923, 1932; Percival 1910). [ABSTRACT FROM AUTHOR]