Search results for "Plant Root"
showing 10 items of 232 documents
Effect of natamycin on the enumeration, genetic structure and composition of bacterial community isolated from soils and soybean rhizosphere
2004
Natamycin is commonly used to control fungal growth on agar media used for bacterial enumeration or strain isolation. However, there is no conclusive report on the possible effect of this antibiotic on bacterial growth or on the diversity of the recovered soil bacteria. Therefore, the possible effects of natamycin on the numbers of bacteria isolated at 12 degrees C from three different soils and soybean rhizosphere soil were investigated using natamycin concentrations ranging from 0 to 200 mg l(-1). Our results demonstrate that natamycin concentrations, which inhibit the growth of fungi on the media, have a small but significant inhibitory effect on the number of bacterial colony forming un…
Identification of bacterial groups preferentially associated with mycorrhizal roots of Medicago truncatula
2007
ABSTRACT The genetic structures of bacterial communities associated with Medicago truncatula Gaertn. cv. Jemalong line J5 (Myc + Nod + ) and its symbiosis-defective mutants TRV48 (Myc + Nod − ) and TRV25 (Myc − Nod − ) were compared. Plants were cultivated in a fertile soil (Châteaurenard, France) and in soil from the Mediterranean basin showing a low fertility (Mas d'Imbert, France). Plant growth, root architecture, and the efficiency of root symbiosis of the three plant genotypes were characterized in the two soils. Structures of the bacterial communities were assessed by automated-ribosomal intergenic spacer analysis (A-RISA) fingerprinting from DNA extracted from the rhizosphere soil an…
Distribution and diversity of type III secretion system-like genes in saprophytic and phytopathogenic fluorescent pseudomonads
2004
Type three secretion systems (TTSSs) are protein translocation mechanisms associated with bacterial pathogenicity in host plants, and hypersensitive reactions in non-host plants. Distribution and diversity of TTSS-like genes within a collection of saprophytic and phytopathogenic fluorescent pseudomonads were characterized. This collection included 16 strains belonging to 13 pathogenic species, and 87 strains belonging to five saprophytic species isolated from plant rhizosphere and soil. Presence of conserved hypersensitive reaction/pathogenicity (hrp) genes (hrc RST) was assessed both by PCR using primers designed to amplify the corresponding sequence and by dot-blot hybridization using a P…
Relative Abundances of Proteobacterial Membrane-Bound and Periplasmic Nitrate Reductases in Selected Environments
2007
ABSTRACT Dissimilatory nitrate reduction is catalyzed by a membrane-bound and a periplasmic nitrate reductase. We set up a real-time PCR assay to quantify these two enzymes, using the narG and napA genes, encoding the catalytic subunits of the two types of nitrate reductases, as molecular markers. The narG and napA gene copy numbers in DNA extracted from 18 different environments showed high variations, with most numbers ranging from 2 × 10 2 to 6.8 × 10 4 copies per ng of DNA. This study provides evidence that, in soil samples, the number of proteobacteria carrying the napA gene is often as high as that of proteobacteria carrying the narG gene. The high correlation observed between narG an…
Tonoplast subcellular localization of maize cytochrome b5 reductases
2000
Plant cytochrome b 5 reductases (b 5 R) are assumed to be part of an ER-associated redox chain that oxidizes NADH to provide electrons via cytochrome b5 (cyt b 5 ) to ER-associated fatty acyl desaturase and related hydroxylases, as in mammalian cells. Here we report on cDNA cloning of a novel maize b 5 R, NFR II, strongly related to a previously cloned cDNA, NFR I (Bagnaresi et al., 1999, Biochem, J. 338, 499-5051. Maize b 5 R isoforms are produced by a small multi-gene family. The NFR cDNAs were shown to encode active b 5 Rs by heterologous expression in yeast. Both reductases, in addition to Fe 3+ -chelates, efficiently reduced Cu 2+ -chelates. Using a polyclonal antibody able to recogniz…
Phytochemical profile and bioactivity of traditional ayurvedic decoctions and hydro-alcoholic macerations of Boerhaavia diffusa L. and Curculigo orch…
2015
Decoctions (DECs) and hydro-alcoholic extracts (HEs) prepared from roots of Boerhaavia diffusa L. (Nyctaginaceae) and Curculigo orchioides Gaertn. (Hypoxidaceae) were phytochemically characterised by HPLC-DAD and profiled for their antioxidant, antigenotoxic and cytotoxic activities. B. diffusa DEC was rich in ferulic acid and vanillin, while the HE also contained boeravinone B and eupalitin. Both C. orchioides HE and DEC displayed the main occurrence of orcinol-β-d-glucoside and curculigoside A. Antioxidant activity was assayed through spectrophotometric DPPH, ABTS and β-carotene bleaching test, and using (HP)TLC bioautographic strategies. For both crude drugs, HE was the best performing p…
Fungal genes related to calcium homeostasis and signalling are upregulated in symbiotic arbuscular mycorrhiza interactions
2012
Fluctuations in intracellular calcium levels generate signalling events and regulate different cellular processes. Whilst the implication of Ca2+ in plant responses during arbuscular mycorrhiza (AM) interactions is well documented, nothing is known about the regulation or role of this secondary messenger in the fungal symbiont. The spatio-temporal expression pattern of putatively Ca2+-related genes of Glomus intraradices BEG141 encoding five proteins involved in membrane transport and one nuclear protein kinase, was investigated during the AM symbiosis. Expression profiles related to successful colonization of host roots were observed in interactions of G. intraradices with roots of wild-ty…
Estimating additional root cohesion by exploiting a root topological model based on Leonardo’s Rule
2020
Root topological models are schematic representations of the root structure based on a defined topology graph theory. In the context of hillslope stabilization modeling against rainfall-induced shallow landslides, the root topological models may be used in combination with root strength models assessment, such as the Root Bundle Model (RBM), to estimate the ultimate root reinforcement. The effect of plant roots on slope stabilization is determined by the interaction between soil and the hydrological processes (within the root zone) and the biotechnical characteristics of the root system, such as root length, root density, root tensile strength, root area, root diameter profile and the total…
Rare earths and trace elements contents in leaves: A new indicator of the composition of atmospheric dust
2017
The relationship between the trace element distribution in atmospheric particles and leaves of some exposed plants in the environment was recently demonstrated. This indication would suggest that the trace element analysis of leaves in these plants could provide information about the composition, nature and origin of the atmospheric dust dispersed in the environment. In order to corroborate this hypothesis, the distribution of trace elements and Rare Earths were studied in leaves of some endemic plants, in the atmospheric fallout and in soils of rural, urban and industrial ecosystems in Sicily. These elements have been chosen to discriminate the source and nature of different source on atmo…
Two new biologically active triterpenoidal saponins acylated with salicylic acid from Albizia adianthifolia
2003
International audience; Two new oleanane-type triterpene saponins, adianthifoliosides A (1) and B (2), were isolated from a 95% ethanolic extract of roots of Albizia adianthifolia. Their structures were elucidated mainly by using a combination of 600 MHz 1D and 2D NMR techniques (COSY, NOESY, TOCSY, HSQC, and HMBC) and by FABMS and HRESIMS. Compounds 1 and 2 were characterized as glycosides of acacic acid acylated by an o-hydroxybenzoyl unit. The crude saponin mixture (CSM), compounds 1 and 2 together with 3 and 4 (prosapogenins obtained from the mild alkaline hydrolysate of the CSM), were evaluated for immunomodulatory activity on the Jurkat T cell line and for hemolytic property against s…