Search results for "oomycete"
showing 10 items of 37 documents
A new species of Pythium with ornamented oogonia: morphology, taxonomy, internal transcribed spacer region of its ribosomal RNA, and its comparison w…
2006
Pythium spiculum sp. nov. was isolated from soil samples taken in a vineyard in the Burgundian region of France and from different locations in Spain and Portugal. The oomycete has spiny oogonia and does not sporulate readily. It resembles Pythium mamillatum Meurs, but has its own distinguishing characteristics. It also exhibits sickle-shaped as well as spherical appressoria which at times are associated with sex organs like those found in Pythium abappressorium Paulitz and Pythium contiguanum Paul. Sequencing of the internal transcribed spacer region of its nuclear ribosomal DNA and a close look at its morphological characters have now enabled us to describe it as a new species. The intern…
A β-1,3 Glucan Sulfate Induces Resistance in Grapevine against Plasmopara viticola Through Priming of Defense Responses, Including HR-like Cell Death
2008
Sulfated laminarin (PS3) has been shown previously to be an elicitor of plant defense reactions in tobacco and Arabidopsis and to induce protection against tobacco mosaic virus. Here, we have demonstrated the efficiency of PS3 in protecting a susceptible grapevine cultivar (Vitis vinifera cv. Marselan) against downy mildew (Plasmopara viticola) under glasshouse conditions. This induced resistance was associated with potentiated H2O2 production at the infection sites, upregulation of defense-related genes, callose and phenol depositions, and hypersensitive response-like cell death. Interestingly, similar responses were observed following P. viticola inoculation in a tolerant grapevine hybri…
Saprolegnia multispora, a new oomycete isolated from water samples taken in a river in the Burgundian region of France
2004
Saprolegnia multispora is described from water and floating organic matter taken in the Tille River, in the Burgundian region of France. The new species is illustrated and compared with other species of the genus. Distinguishing characteristics of S. multispora are the production of smooth-walled oogonia containing many subcentric oospores which are (1−) 11–70 (−100) per oogonium. The antheridial branches supplying the oogonia are predominantly diclinous, but at times these may be monoclinous and androgynous. Morphological features of the oomycete and the sequence of the ITS region of its rDNA as well as their comparison with related species are discussed in this article.
Pythium campanulatumsp. nov., isolated from the rhizosphere of maize, its taxonomy, ITS region of rDNA, and comparison with related species
2003
Pythium campanulatum sp. nov. was isolated from some soil samples taken in the rhizosphere of maize (Zea mays) in north-eastern India. This species is characterized by the absence of zoospores and sporangia, antheridial branches wrapping around the oogonia leaving one to two campanulate antheridial cells after fertilization, and aplerotic oospores. The ITS region of its rDNA is comprised of 922 bases. This oomycete is closely related to Pythium orthogonon, Pythium nunn and Pythium toruloides. However, it has its own characteristic features and is completely devoid of zoospores. Taxonomic description of this new species and its comparison with related oomycetes, together with the sequence of…
Intraspecific variability in the Oomycete plant pathogen Phytophthora nicotianae
2011
Phytophthora nicotianae is an Oomycete plant pathogen affecting a broad range of plant species comprising more than 250 genera. It causes several economically relevant diseases and is particularly known as the causal agent of black shank of tobacco and root rot, stem rot and gummosis of citrus. Despite the relevance of this pathogen, information on the field reproductive strategy, population structure and global distribution of genetic variability is not completely known. This is because available studies have been conducted to characterize local populations (mainly from tobacco) or have been based on physiological aspects such as resistance to fungicides and pathogenicity on differential h…
Pythium glomeratum, a new species isolated from agricultural soil taken in north-eastern France, its ITS region and its comparison with related speci…
2003
Pythium glomeratum sp. nov. is described here. It was isolated from soil samples taken in the northern France in 1992, was wrongly identified as Pythium heterothallicum and was kept aside. Recently, the ITS region of the rDNA of this oomycete was amplified and sequenced. The differences between the sequence and a more detailed study of the morphological characters of these two species, revealed that both are related but different species. P. glomeratum is characterized by the presence of branched antheridia that wrap around the oogonia, aplerotic to almost plerotic oospores, and the lack of zoosporangia and zoospores. Taxonomical description of this new species, its comparison with related …
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…
Are elicitins cryptograms in plant-oomycete communications?
1999
Stimulation of plant natural defenses is an important challenge in phytoprotection prospects. In that context, elicitins, which are small proteins secreted by Phytophthora and Pythium species, have been shown to induce a hypersensitive-like reaction in tobacco plants. Moreover, these plants become resistant to their pathogens, and thus this interaction constitutes an excellent model to investigate the signaling pathways leading to plant resistance. However, most plants are not reactive to elicitins, although they possess the functional signaling pathways involved in tobacco responses to elicitin. The understanding of factors involved in this reactivity is needed to develop agronomic applica…
Co-Infections by Fusarium circinatum and Phytophthora spp. on Pinus radiata: Complex Phenotypic and Molecular Interactions
2021
13 Pág. Instituto de Ciencias Forestales (ICIFOR)