Search results for "Pythium"
showing 10 items of 41 documents
A new species of Pythium isolated from a vineyard in France.
2006
Pythium apiculatum sp. nov. is a new oomycete characterized by the presence of both ornamented and smooth-walled oogonia. The ornamentations are blunt, and at times, bent. The oomycete was isolated from soil samples taken in a vineyard in the Burgundian region of France. Morphologically, it resembles some species having ornamented oogonia like Pythium radiosum, Pythium echinulatum, and resembles, also the species having smooth-walled oogonia like Pythium hypogynum and Pythium acrogynum. However, the oomycete has its own distinguishing characteristics which, when combined with molecular features, enables us to describe it as a new species. The taxonomic description of this new oomycete, its …
A new species of Pythium with inflated sporangia and coiled antheridia, isolated from India
2008
Pythium kashmirense sp. nov. was isolated from soil samples taken on the Himalayas at the height of 5300 feet in the Shivalik Hill Range of the northern Indian state of Jammu and Kashmir. The oomycete has filamentous-inflated type sporangia and its antheridial filaments form loose loops around the female gametangia, and coil around the oogonial stalks. The new species is closely related to Pythium plurisporium, Pythium periilum, Pythium inflatum, and Pythium folliculosum. All of these oomycetes have filamentous-inflated type sporangia. However, P. kashmirense has its own distinguishing characteristics which can easily differentiate it among these related species. The sequences of the intern…
Crystallization and preliminary X-ray studies of oligandrin, a sterol-carrier elicitor fromPythium oligandrum
2000
Oligandrin is a 10 kDa acidic protein produced by the fungus micromycete Pythium oligandrum and is a member of the alpha-elicitin group, with sterol- and lipid-carrier properties. Oligandrin has been crystallized at 290 K using PEG 4000 as a precipitant. A cholesterol complex was obtained under the same conditions. The space group of the crystals at low temperature (100 K) is C222, with unit-cell parameters a = 94.0, b = 171.1, c = 55.3 A. Four molecules are present in the asymmetric unit. Data from the free and cholesterol-complexed forms were recorded at synchrotron sources to resolutions of 2.4 (uncomplexed) and 1.9 A (complexed), respectively.
ITS region of the rDNA of Pythium rhizosaccharum sp. nov. isolated from sugarcane roots: taxonomy and comparison with related species.
2003
Pythium rhizosaccharum (F-1244) was isolated from soil samples taken in the rhizosphere of sugarcane (Saccharum officinarum) in the north-eastern India. This species is characterized by its smooth-walled, spherical sporangia and rarely formed sexual structures. When formed, the antheridial branches wrap around the oogonia and soon disappear after fertilization. The internal transcribed spacer (ITS) region of its rDNA is comprised of 904 bases. The taxonomical description of this new species and its comparison with related species are given here, together with the nucleotide sequences of the ITS1 and ITS2, and the 5.8S gene of its ribosomal nuclear DNA.
Pythium perplexum isolated from soil in France: morphology, molecular characterisation and biological control.
2001
Pythium perplexum (F-926) was isolated from a soil sample taken in the Burgundy region in France. In 1907, it was mistakenly described by Bulter as P. vexans. Despite morphological resemblance, the comparison between the internal transcribed spacer 1 regions of the ribosomal DNA of the two fungi leaves no doubt of their different identities. P. perplexum was found to be highly pathogenic to cucumber seedlings. Damping-off disease of cucumber caused by P. perplexum can effectively be controlled by using the soil bacterium Serratia plymuthica (B-781). The details of the morphology and the molecular characterisation of P. perplexum and its biological control with S. plymuthica are described he…
Pythium regulare sp. nov., Isolated from the Canary Islands, Its Taxonomy, Its Region of rDNA, and Comparison with Related Species
2003
Pythium regulare (CI-34) was isolated from some soil samples taken in the Canary Islands (Spain). This new species is very closely related to P. irregulare isolated from pea roots in The Netherlands by Buisman in 1927. The species of Pythium are members of the kingdom Chromista. Pythium regulare is characterized by its ornamented oogonia bearing blunt or digitate spines, and its non-sporulating type of sporangia or hyphal bodies, its aplerotic oospores, its monoclinous and diclinous antheridia that at times crowd around the oogonia. The taxonomic description of this oomycete, the PCR of the internal transcribed region (spacers ITS1, ITS2, and the gene 5.8 S) of its ribosomal nuclear DNA as …
Pythium carbonicum, a new species isolated from a spoil heap in northern France, the ITS region, taxonomy and comparison with related species.
2003
Pythium carbonicum (F-72) sp. nov. was found in soil samples taken on the top of a spoil heap in northern France. The morphology of this new species resembles that of a recently described species: Pythium megacarpum. However, the antheridial and oogonial characteristics of this new species are unique, and the comparison of its ITS region of the nuclear ribosomal DNA indicates that this species is also related to the genus Phytophthora. The fungus does not sporulate, the sporangia germinate directly into mycelium through germ tubes. The oogonia of P. carbonicum are smooth-walled and also papillated, and are provided with monoclinous and diclinous antheridia that wrap around, forming a compli…
Pythium stipitatumsp. nov. isolated from soil and plant debris taken in France, Tunisia, Turkey, and India
2009
Pythium stipitatum is a slow-growing oomycete and has been isolated from soil samples and plant materials from France, Tunisia, Turkey and India. Its morphological characteristics are reminiscent of those of Pythium ramificatum, discovered in Algeria by the corresponding author. Unfortunately, the Algerian isolate was not deposited in any culture collection and ultimately got lost. Those were the days when molecular description of fungi was not a fashion; hence, no molecular characteristics of the Algerian isolates were deposited to the GenBank. Moreover, its coralloid antheridial branches made it an easy prey to be considered as synonymous to Pythium minus. Because there are no living stra…
Suppression ofBotrytis cinereacausing the grey mould disease of grape-vine by an aggressive mycoparasite,Pythium radiosum
1999
Pythium radiosum Paul has been found to be an aggressive mycoparasite of Botrytis cinerea which causes grey mould disease on the grape-vine. The mycoparasitic fungus enters the host mycelium, coagulates its protoplasm, empties its contents and finally comes out producing numerous ramifications and sexual structures. When the infected mycelium of B. cinerea is applied to the leaves of the grape-vine, the characteristic grey mould symptoms fail to appear. Since P. radiosum causes no harm to the grape-vine, it can be used as a biological control agent against B. cinerea. A brief account of the mycoparasite and its antagonism towards B. cinerea is discussed here.
ITS region of Pythium canariense sp. nov., its morphology and its interaction with Botrytis cinerea.
2002
A new species Pythium canariense (CI-07), isolated from soil samples taken in the San Nicolas region of the Canary islands (Gran Canaria, Spain), is being described here. This species is characterised by its spherical to pyriform, intercalary to catenulate sporangia, smooth-walled terminal oogonia supplied with monoclinous and diclinous antheridia which at times are branched and wrap around the female gametangia. The fungus has an antagonistic effect on Botrytis cinerea, the grey mould fungus. Morphological features are being given here together with the sequence of the complete internal transcribed spacer region of the nuclear ribosomal DNA of the fungus, its comparison with related specie…