| the pre-symbiotic growth of arbuscular mycorrhizal fungi is induced by a branching factor partially purified from plant root exudates. | arbuscular mycorrhizal (am) symbiosis is an association between obligate biotrophic fungi and more than 80% of land plants. during the pre-symbiotic phase, the host plant releases critical metabolites necessary to trigger fungal growth and root colonization. we describe the isolation of a semipurified fraction from exudates of carrot hairy roots, highly active on germinating spores of gigaspora gigantea, g. rosea, and g. margarita. this fraction, isolated on the basis of its activity on hyphal b ... | 2000 | 10830269 |
| arbuscular mycorrhizal fungi alter phosphorus relations of broomsedge (andropogon virginicus l.) plants. | broomsedge (andropogon virginicus l.) is a dominant grass revegetating many abandoned coal-mined lands in west virginia, usa. residual soils on such sites are often characterized by low ph, low nutrients, and high aluminium. experiments were conducted to assess the resistance of broomsedge to limited phosphorus (pi) availability and to investigate the role that arbuscular mycorrhizal (am) fungi play in aiding plant growth under low pi conditions. pregerminated mycorrhizal and non-mycorrhizal see ... | 2001 | 11520877 |
| a diffusible factor from arbuscular mycorrhizal fungi induces symbiosis-specific mtenod11 expression in roots of medicago truncatula. | using dual cultures of arbuscular mycorrhizal (am) fungi and medicago truncatula separated by a physical barrier, we demonstrate that hyphae from germinating spores produce a diffusible factor that is perceived by roots in the absence of direct physical contact. this am factor elicits expression of the nod factor-inducible gene mtenod11, visualized using a pmtenod11-gusa reporter. transgene induction occurs primarily in the root cortex, with expression stretching from the zone of root hair emerg ... | 2003 | 12644648 |
| 'candidatus glomeribacter gigasporarum' gen. nov., sp. nov., an endosymbiont of arbuscular mycorrhizal fungi. | arbuscular mycorrhizal fungi are obligate endosymbionts that colonize the roots of almost 80 % of land plants. the present paper describes morphological and molecular data on a bacterial endosymbiont living in the cytoplasm of dormant or germinating spores and symbiotic mycelia of the fungal species gigaspora margarita, scutellospora persica and scutellospora castanea. pcr amplification of almost the entire 16s rrna gene of the gigaspora margarita beg 34 endosymbiont, using universal bacterial p ... | 2003 | 12656162 |
| root exudate of pmi tomato mutant m161 reduces am fungal proliferation in vitro. | soluble factors released from roots of the pre-mycorrhizal infection (pmi) myc(-) tomato mutant m161 were analyzed and compared with normal wild-type released factors. aseptic whole exudates from the m161 mutant retarded the proliferation of glomus intraradices in vitro. when the whole exudate was further fractionated on a c18 sepak cartridge, the 50/70% methanol fraction showed an activity against hyphal tip growth of gigaspora gigantea and gl. intraradices. preliminary characterization of the ... | 2003 | 12829285 |
| action spectrum for the induction of hyphal branches of an arbuscular mycorrhizal fungus: exposure sites versus branching sites. | the first action spectrum for a photo-induced response of an arbuscular mycorrhizal fungus is reported. at low light intensity, the responsive wavelengths for light-induced hyphal branching of the primary germ tube of gigaspora gigantea were determined to be in the blue to uv-a range. the action spectrum showed the greatest stimulation of branching occurred around 390 nm although a shoulder was observed between 360-370 nm. a second major peak of light-induced branching occurred at 430 nm. the ex ... | 2003 | 14563135 |
| use of sucrose-agar globule with root exudates for mass production of vesicular arbuscular mycorrhizal fungi. | a sucrose-agar globule (sag) was newly introduced to increase production of the vesicular arbuscular mycorrhizal (vam) fungal spores, gigaspora gigantea and glomus fasciculatum. an sag inoculum and a sucrose-agar globule with root exudates (sage) inoculum were prepared, and their spore productions were compared with a soil inoculum. when the sage was used as the inoculum on sucrose-agar medium plates the number of spores was increased (35% more than the soil inoculum). after the soil inoculum an ... | 2004 | 15357295 |
| isolated root caps, border cells, and mucilage from host roots stimulate hyphal branching of the arbuscular mycorrhizal fungus, gigaspora gigantea. | unlike previous reports that have shown that water soluble and volatile compounds from roots or root exudates play an important role in precolonization events during arbuscular mycorrhizal (am) fungus-host root interactions (bécard & piché 1989, giovannetti et al. 1993), the results shown here deal with particulate and viscous fractions isolated from host roots. root caps and a slow sedimenting particulate fraction (sspf) were rapidly isolated and separated from ri t-dna transformed carrot roots ... | 2004 | 15506019 |
| separated components of root exudate and cytosol stimulate different morphologically identifiable types of branching responses by arbuscular mycorrhizal fungi. | two morphologically distinct hyphal branching responses by the am fungus, glomus intraradices, were stimulated by separated components of carrot root exudate. complex branching up to the sixth order was induced by compounds most soluble in 35% methanol, whereas the formation of more lateral branches (second order) was stimulated by compounds most soluble in 70% methanol. this same 70% alcohol soluble fraction also stimulated a completely different type of branching pattern in another fungus, gig ... | 2007 | 17544057 |
| isolation and sequence analysis of a beta-tubulin gene from arbuscular mycorrhizal fungi. | a full-length beta-tubulin gene has been cloned and sequenced from gigaspora gigantea and glomus clarum, two arbuscular mycorrhizal fungi (amf) species in the phylum glomeromyota. the gene in both species is organized into five exons and four introns. both genes are 94.9% similar and encode a 447 amino acid protein. in comparison with other fungal groups, the amino acid sequence is most similar to that of fungi in the chytridiomycota. the codon usage of the gene in both amf species is broad and ... | 2009 | 19444489 |
| synergism between blue light and root exudate compounds and evidence for a second messenger in the hyphal branching response of gigaspora gigantea. | light and chemical components of the host root exudate can induce hyphal growth and branching of arbuscular mycorrhizal fungi. compounds that induce the same morphogenetic or biochemical response as light are referred to as photo-mimetic compounds (pcs). this is the first report of a synergistic response by gigaspora gigantea, an arbuscular mycorrhizal fungus, to blue light and naturally occurring photomimetic compounds isolated from the exudate of host roots. the blue light treatment and exposu ... | 2004 | 21148915 |
| amplified fragment length microsatellites (aflm) might be used to develop microsatellite markers in organisms with limited amounts of dna applied to arbuscular mycorrhizal (am) fungi. | developing microsatellite markers for organisms with limited amounts of dna can be difficult because sequence information is needed. to overcome this problem in the arbuscular mycorrhizal (am) fungi glomus etunicatum and gigaspora gigantea, global amplification of the genomes of each species was performed with linker-adaptor-pcr from single spores. amplified fragments were enriched for microsatellite motifs with 5'-biotinylated oligonucleotides and recovered by magnetic streptavidin beads. the r ... | 2003 | 21156624 |
| in situ analysis of anastomosis in representative genera of arbuscular mycorrhizal fungi. | arbuscular mycorrhizal fungi (amf) form obligate symbiotic associations with plants. as a result, the role of hyphal interactions in the establishment and maintenance of common mycorrhizal networks is poorly understood because of constraints on methods for in situ analysis. we designed a rhizohyphatron that allows the examination of intact mycelia growing from whole mycorrhizal plants. plants preinoculated with spores were cultivated in a compartment with a connecting tube from which hyphae exte ... | 2011 | 21221661 |
| the effects of hydroxy fatty acids on the hyphal branching of germinated spores of am fungi. | two hydroxy fatty acids, tentatively identified previously in carrot root exudates, were tested for their effects on hyphal growth of the arbuscular mycorrhizal (am) fungus, gigaspora gigantea (nicol. and gerd.) gerdemann and trappe. best results were achieved with a long-term bioassay (7-8d) with nanomolar concentrations throughout the petri dish in contrast to the rapid microinjection bioassay (16-24h) in which nanogram quantities were injected near growing hyphal tips. when 5nm 2-hydroxy fatt ... | 2011 | 21530917 |
| divergent phenologies may facilitate the coexistence of arbuscular mycorrhizal fungi in a north carolina grassland. | interest in the diversity of arbuscular mycorrhizal (am) fungal communities has been stimulated by recent data that demonstrate that fungal communities influence the competitive hierarchies, productivity, diversity, and successional patterns of plant communities. although natural communities of am fungi are diverse, we have a poor understanding of the mechanisms that promote and maintain that diversity. plants may coexist by inhabiting disparate temporal niches; plants of many grasslands are eit ... | 2002 | 21665745 |