Search results for "oomycete"
showing 10 items of 37 documents
TheMedicago truncatulahypermycorrhizal B9 mutant displays an altered response to phosphate and is more susceptible toAphanomyces euteiches
2014
Inorganic phosphate (Pi) plays a key role in the development of arbuscular mycorrhizal (AM) symbiosis, which is favoured when Pi is limiting in the environment. We have characterized the Medicago truncatula hypermycorrhizal B9 mutant for its response to limiting (P/10) and replete (P2) Pi. On P2, mycorrhization was significantly higher in B9 plants than in wild-type (WT). The B9 mutant displayed hallmarks of Pi-limited plants, including higher levels of anthocyanins and lower concentrations of Pi in shoots than WT plants. Transcriptome analyses of roots of WT and B9 plants cultivated on P2 or on P/10 confirmed the Pi-limited profile of the mutant on P2 and highlighted its altered response t…
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…
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.
Influence of leaf age on induced resistance in grapevine against Plasmopara viticola
2012
International audience; Sulfated laminarin (PS3) has previously been shown to induce resistance of grapevine leaves against the oomycete Plasmopara viticola, the causal agent of grape downy mildew. Here, we observed that the level of PS3-induced resistance (PS3-IR) was higher in the adult leaf (in position P3) than in the younger, not fully expanded leaf (in position P1, located above P3). By investigating grapevine defense reactions upon PS3 treatment and inoculation, we found that the production of H2O2, of phytoalexins, and the deposition of phenolics were more abundant in P3 than in P1 leaves. In addition, PS3 significantly reduced stomatal colonization by zoospores only in P3 leaves. T…
Co-Infections by Fusarium circinatum and Phytophthora spp. on Pinus radiata: Complex Phenotypic and Molecular Interactions
2021
13 Pág. Instituto de Ciencias Forestales (ICIFOR)
Antimicrobial Activity of Resveratrol Analogues
2014
Stilbenes, especially resveratrol and its derivatives, have become famous for their positive effects on a wide range of medical disorders, as indicated by a huge number of published studies. A less investigated area of research is their antimicrobial properties. A series of 13 trans-resveratrol analogues was synthesized via Wittig or Heck reactions, and their antimicrobial activity assessed on two different grapevine pathogens responsible for severe diseases in the vineyard. The entire series, together with resveratrol, was first evaluated on the zoospore mobility and sporulation level of Plasmopara viticola (the oomycete responsible for downy mildew). Stilbenes displayed a spectrum of acti…
Isolation frequency and efficiency of mycoparasitic Pythium species in the West Mediterranean region of Turkey
2021
Abstract A total of 132 mycoparasitic Pythium isolates were obtained from the soil samples taken from fruit orchards, vegetable fields, carnation greenhouses, sugarbeet fields and cereal fields in the West Mediterranean region of Turkey. The Oomycetes were isolated by using; surface soil dilution plate, sclerotia bait and precolonised plate methods. Isolates were identified as P. acanthophoron, P. amasculinum, P. lycopersicum, P. oligandrum, P. periplocum and P. paroecandrum, according to their morphological and molecular characteristics. The most commonly isolated mycoparasitic species were P. amasculinum and P. lycopersicum. The majority of the mycoparasites came from soil samples taken f…
From elicitins to lipid-transfer proteins: a new insight in cell signalling involved in plant defence mechanisms.
2002
Elicitins and lipid-transfer proteins are small cysteine-rich lipid-binding proteins secreted by oomycetes and plant cells, respectively, that share some structural and functional properties. In spite of intensive work on their structure and diversity at the protein and genetic levels, the precise biological roles of lipid-transfer proteins remains unclear, although the most recent data suggest a role in somatic embryogenesis, in the formation of protective surface layers and in defence against pathogens. By contrast, elicitins are known elicitors of plant defence, and recent work demonstrating that elicitins and lipid-transfer proteins share the same biological receptors gives a new perspe…
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…