Chytridiomycetes are water-inhabiting fungi, often parasitic on algae and oomycetes, or soil inhabitants, some of which are parasitic on vascular plants. A few chytrids parasitize animal eggs and protozoa, while others are saprobic on the decaying remains of plants. Multigene phylogenetic analyses, new culture techniques, and additional collections of Chytridiomycetes have revealed greater diversity and led to increased numbers of orders in which to classify about 700 species in under 90 genera. Today there are 10 described orders of Chytridiomycetes: Chytridiales, Spizellomycetales, Cladochytriales, Rhizophydiales, Polychytriales, Rhizophlyctidales, Lobulomycetales, Synchytriales, Gromochytriales, and Mesochytriales. An exemplar life cycle is that of Chytriomyces hyalinus, which forms a well-developed rhizoidal system within its substrate. The sporangium that develops from the encysted zoospore has a saucer-shaped operculum from which zoospores escape into a fib...
Physoderma is a genus of chytrid fungi. Described by German botanist Karl Friedrich Wilhelm Wallroth in 1833, the genus contains some species that are parasitic on vascular plants, including P. alfalfae and P. maydis , causative agents of crown wart of alfalfa and brown spot of corn, respectively. [3] Of the chytrid genera, Physoderma is the oldest. [4] However, species were confused with the rust fungi , the genus Synchytrium , and the genus Protomyces of Ascomycota . [5] Members of Physoderma are obligate parasites of pteridophytes and angiosperms . [4] There are approximately 80 species within this genus (depending on whether one includes those traditionally belonging to Urophlyctis ). [5] Taxonomic History [ edit ] The genus was erected in 1833 on the basis of resting spore developme...
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