Search results for "Antheridium"
showing 10 items of 23 documents
Achlya spiralis, a new aquatic oomycete with bent oogonial stalks, isolated from the Burgundian region of France
2008
Achlya spiralis sp. nov. was isolated from water samples collected in the river Tille in the Burgundian region of France. The new oomycete is described, illustrated and compared with related species of the genus Achlya. It is characterized by the presence of smooth-walled oogonia that are usually borne on bent or twisted oogonial stalks; mainly monoclinous, androgynous and diclinous antheridial branches and eccentric oospores which generally do not mature or mature after a long period of time. The internal transcribed spacer (ITS) region of its rRNA is comprised of 671 bases. The taxonomic description of this new species, its comparison with related oomycetes and the sequence of the ITS reg…
Morphological and molecular taxonomy ofPythium longisporangiumsp. nov. isolated from the Burgundian region of France
2005
During the course of an investigation on the Pythiaceous oomycetes occurring in the Burgundian vineyards, some species of Pythium possessing mainly hypogynous antheridia were found. These had been classified as oomycetes belonging to the ‘‘Pythium rostratum’’ group for a long time. Three of these isolates, having similar structures and growth, are very closely related to a recently described species, Pythium bifurcatum Paul. A close look at these, however, underlines some fundamental differences with the latter. Not all of them produce zoospores but have very large sporangia. The type specimen is F-1200 (B 76a) which is a medium-slow growing saprophyte. The sequence of the ITS region of the…
Pythium prolatumisolated from soil in the Burgundy region: a new record for Europe
1999
Pythium prolatum Hendrix and Campbell has been isolated from a soil sample taken in the Burgundy region in France. The fungus is easily recognisable by its heavily ornamented oogonia with conical to mammiform spines, elongated sporangia, and its diclinous antheridia forming or originating from a tangled mass of hyphae. Descriptions of the morphological and reproductive aspects of Pythium prolatum, the polymerase chain reaction of the internal transcribed spacer (ITS1) of the ribosomal nuclear DNA as well as the nucleotide sequences of ITS1 coding for 5.8 S rRNA are given.
Pythium segnitiumsp. nov., isolated from the Canary Islands â its taxonomy, ITS region of rDNA, and comparison with related species
2002
Pythium segnitium (CI-44) was isolated from some soil samples taken in the Canary Islands (Spain). This new species is a slow-growing fungus and is perfectly adapted to terrestrial habitat. It belongs to the group of Pythium that have smooth-walled oogonia, mostly hypogynous antheridia, and plerotic oospores. The fungus lacks sporangia, zoospores, and hyphal bodies are rarely formed. Thus the asexual reproduction, which is so common for fungi and especially for the aquatic ones, is completely lacking in this case. However the fungus reproduces sexually by the formation of oogonia, antheridia and oospores plentifully. The taxonomic description of this fungus, the nucleotide sequence of the i…
Characterisation of a new species of Pythium isolated from a wheat field in northern France and its antagonism towards Botrytis cinerea causing the g…
2003
A new species, Pythium bifurcatum, isolated from soil samples taken from a wheat field in Lille in northern France is described here. The oomycete occurred thrice out of 50 samples. The type specimen is F-91, which is a slow-growing saprophyte living on vegetable debris and which can be recognised by its antheridial as well as oogonial characteristics, which are different from other known species of Pythium. When grown together with Botrytis cinerea, the causal agent of the grey mould disease of the grapevine, Pythium bifurcatum shows a pronounced antagonism and suppresses its growth. Morphological features of this new species, its antagonism to B. cinerea, the sequences of the ITS region o…
Pythium burgundicum sp. nov. isolated from soil samples taken in French vineyards.
2009
During the course of investigation on pythiaceous fungi occurring in the Burgundian vineyards, a new species of Pythium has been isolated. This oomycete is characterized by its nonproliferating and nonsporulating, spherical to cylindrical type of sporangia (hyphal bodies) germinating through germ tubes, smooth-walled oogonia that are supplied with hypogynous, monoclinous or rarely diclinous antheridia, and smooth-walled oospores. The antheridial cells are very prominent and are reminiscent of Pythium bifurcatum, Pythium segnitium and Pythium longandrum described previously by the author. The internal transcribed spacer region of the rRNA of this new species is composed of 883 bases, which i…
A new species of Pythium isolated from the Burgundy region in France.
1998
Pythium nodosum sp. nov. has been isolated from a soil sample taken in the Burgundy region in France. The fungus has spherical to variously shaped proliferating sporangia, smooth-walled oogonia which are crowded with different antheridial branches making a complicated knot around the former, and aplerotic oospores. Morphological and reproductive aspects of Pythium nodosum as well as the PCR of the internal transcribed spacer (ITS1) of the ribosomal nuclear DNA coupled with restriction fragment length polymorphism analysis are described here. The nucleotide sequences of ITS1 encoding 5.8S rRNA is also given.
Pythium ornacarpum: a new species with ornamented oogonia isolated from soil in France
1999
Pythium ornacarpum sp. nov. was isolated from a soil sample taken from Genlis in the Burgundy region of France. This species is unique because of its ornamented oogonia which are completely surrounded by antheridial filaments. The fungus is closely related to Pythium echinulatum Matthews. Morphological and reproductive aspects of this species as well as a study by PCR of the sequence of the internal transcribed spacer (ITS1) of the nuclear ribosomal gene and its comparison with related species are described here. The nucleotide sequence of the ITS1 region flaking the 5.8S rRNA of this species and other related species are also given here.
A new species of Pythium with filamentous sporangia having pectinolytic activities, isolated in the Burgundy region of France.
2001
A new species, Pythium pectinolyticum (F-83.1), isolated from soil samples taken in the Burgundy region is being described here. This species is characterised by its filamentous non-inflated type of sporangia, smooth-walled mostly catenulate oogonia and very rare antheridia. This fungus is a very slow-growing organism on most of the solid media, but it grows well in liquid media and also on those containing pectin as the sole source of carbon. Morphological features are described here together with the sequences of the internal transcribed spacer 1 region of the nuclear ribosomal DNA of the fungus, its comparison with related species, and its pectinolytic behaviour.
Pythium terrestris, a new species isolated from France, its ITS region, taxonomy and its comparison with related species
2002
Pythium terrestris (F-78) was isolated from soil samples taken in Lille in northern France. Its morphology resembles that of Pythium rostratum, and Pythium longandrum, a recently described species. However the antheridial and sporangial characteristics of this new species are unique. The fungus does not sporulate, the sporangium germinates directly into mycelium through germ tubes. The oogonia of P. terrestris are normally provided with hypogynous and monoclinous antheridia, at times the monoclinous antheridial branches wrap around the oogonia forming a complicated knot. Morphological features of this new species, together with the sequences of the internal transcribed spacer (ITS) region o…