Search results for "Phycomycetes"
showing 9 items of 9 documents
Pythium periplocum, an aggressive mycoparasite of Botrytis cinerea causing the gray mould disease of grape-vine.
1999
Pythium periplocum Dreschler has been found to be an aggressive mycoparasite of Botrytis cinerea, the causal agent of the gray mould disease of the grape-vine. When grown together, the former enters the latter's mycelium, branches freely within, coagulates its cytoplasm and finally tears its hyphae apart, bringing about widespread destruction of the grape-vine pathogen. Extensive coiling around the host, as reported in the case of other mycoparasites belonging to the genus Pythium, has not been observed here. The infected mycelium of B. cinerea fails to infect the grape-vine and does not induce the characteristic gray mould symptoms. Since P. periplocum is not a grape-vine parasite, it coul…
Influence of nitrogen on accumulation of isosojagol ( a newly detected coumestan in soybean ) and associated isoflavonoids in roots and nodules of my…
1991
International audience
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…
The development of sporangia of Phytophthora infestans
1995
The dynamics of sporulation and zoosporogenesis of Phytophthora infestans in a naturally infected crop of potato cv. Maris Bard and on potted plants of the same cultivar infected artificially with the same fungus are described. Development of sporangiophores and sporangia was synchronous after induction. Migration of several nuclei from the sporangiophore into the sporangium initial was followed by nuclear division, then by degeneration of a proportion of the nuclei. Sporangia then became deciduous, developed papillae and became able to release zoospores in rapid succession. When infected leaves were detached and transferred from the field to moist Petri dishes, sporulation was at first syn…
Localized versus systemic effect of arbuscular mycorrhizal fungi on defence responses to Phytophthora infection in tomato plants
2002
Development of biological control for plant diseases is accepted as a durable and environmentally friendly alternative for agrochemicals. Arbuscular mycorrhizal fungi (AMF), which form symbiotic associations with root systems of most agricultural, horticultural and hardwood crop species, have been suggested as widespread potential bioprotective agents. In the present study the ability of two AMF (Glomus mosseae and Glomus intraradices) to induce local or systemic resistance to Phytophthora parasitica in tomato roots have been compared using a split root experimental system. Glomus mosseae was effective in reducing disease symptoms produced by P. parasitica infection, and evidence points to …
Saprolegnia bulbosa sp. nov. isolated from an Argentine stream: taxonomy and comparison with related species
2007
Saprolegnia bulbosa sp. nov. was isolated from floating and decaying twigs and leaves in El Gato stream, Partido de La Plata, Buenos Aires Province, Argentina. The distinctive characteristics of S. bulbosa are the product of smooth oogonia and predominantly contorted monoclinous, androgynous and diclinous antheridia. The oogonial stalks are usually bent, curved or once coiled; oospores are subcentric, (1) 2–15 (45) per oogonium and are variable in size. Taxonomical description of this new species, its comparison with related oomycetes of the genus and the nucleotide sequences of the internal transcribed region (spacers ITS1, ITS2 and the gene 5.8S) of its rRNA gene are given here.
The use of glyphosate as the sole source of phosphorus or carbon for the selection of soil-borne fungal strains capable to degrade this herbicide
1997
Abstract The herbicide glyphosate was used as a selection agent for isolation of fungal strains capable to degrade phosphorus-to-carbon bond from standard sandy-clay soil. The studies have shown that the herbicide used in Martin medium as a sole source of phosphorus br carbon caused the decrease of the fungal population and substantially changed strain composition, thus selecting those which are able to degrade glyphosate.
A mycorrhiza helper bacterium enhances ectomycorrhizal and endomycorrhizal symbiosis of Australian Acacia species.
2003
The aims of this study were to test the effects of a mycorrhiza helper bacterium (MHB), Pseudomonas monteilii strain HR13 on the mycorrhization of (1) an Australian Acacia, A. holosericea, by several ectomycorrhizal fungi or one endomycorrhizal fungus Glomus intraradices, and (2) several Australian Acacia species by Pisolithus alba strain IR100 under glasshouse conditions. Bacterial inoculant HR13 significantly promoted ectomycorrhizal colonization for all the Acacia species, from 45.8% ( A. mangium) to 70.3% ( A. auriculiformis). A stimulating effect of HR13 on the ectomycorrhizal establishment was recorded with all the fungal isolates (strains of Pisolithus and Scleroderma). The same effe…
Pythium deliense causing severe damping-off of cucumber seedlings and its biological control by soil bacteria
1996
Abstract Pythium deliense Meurs was isolated from cucumber plant debris and was found to be highly pathogenic to cucumber seedlings, causing severe damping-off disease. The fungus however was completely inhibited by a soil bacterium SU-48.1. In vitro and in vivo studies reveal that the disease can be controlled by using this bacterium. The details of the parasitic fungus, the antagonism between the fungus and the bacteria, and the biological control of the disease, are described in this article.