Synchytrium

Synchytrium is a genus of obligate plant-parasitic fungi in the phylum Chytridiomycota, class Chytridiomycetes. It belongs to the family Synchytriaceae and the order Synchytriales. Members are minute chytrids that infect living plant tissue, typically in moist environments where their motile zoospores can swim.

Morphology and life cycle: The thalli are intracellular in host tissue and produce sporangia that release biflagellate zoospores. In many species, infection is followed by the formation of resting spores with thick walls that accumulate in infected tissue and persist in soil for years. The life cycle broadly alternates between a motile zoospore stage in water films and a sessile sporangial stage inside host cells, enabling spread through proximity to infected tissue and contaminated soil.

Ecology and impact: Synchytrium species are obligate parasites of plants, often with narrow host ranges. They are mainly distributed in temperate regions and rely on moisture for zoospore dispersal. The most economically important member is Synchytrium endobioticum, the potato wart pathogen, which causes galls on tubers and stolons and can persist in soil as resting spores, complicating eradication efforts.

Management and taxonomy: Control relies on certified disease-free seed tubers, strict sanitation, and soil and crop management, though resting spores can persist for many years. In plant pathology, S. endobioticum is a quarantined pathogen with defined pathotypes that affect cultivar resistance breeding. The genus includes several described species on diverse hosts, but S. endobioticum is the best known for its agricultural impact.