A5074087888- Legume Nitrogen Fixing Symbiosis
- Plant nutrient uptake and metabolism
- Agronomic Practices and Intercropping Systems
- Nematode management and characterization studies
- Microbial Metabolites in Food Biotechnology
- Coastal wetland ecosystem dynamics
- Plant-Microbe Interactions and Immunity
- Microbial Community Ecology and Physiology
- Polysaccharides and Plant Cell Walls
- Cassava research and cyanide
- Soybean genetics and cultivation
- Cell Image Analysis Techniques
- Plant responses to water stress
- Carbohydrate Chemistry and Synthesis
- Bacterial biofilms and quorum sensing
- Plant Parasitism and Resistance
- Enzyme Production and Characterization
- Biofuel production and bioconversion
- Mycorrhizal Fungi and Plant Interactions
- Soil Carbon and Nitrogen Dynamics
- Image Processing Techniques and Applications
- Plant Micronutrient Interactions and Effects
- Microbial Metabolic Engineering and Bioproduction
- Single-cell and spatial transcriptomics
- Aquatic Ecosystems and Phytoplankton Dynamics
Michigan State University
2010-2019
Australian National University
1986-2001
Ecologie Microbienne Lyon
2000-2001
International Rice Research Institute
1997
Universidad de Salamanca
1995
Estación Experimental del Zaidín
1993
Consejo Superior de Investigaciones Científicas
1993
University of Florida
1974-1989
Experimental Station
1989
Kagoshima University
1989
ABSTRACT Rhizobia, the root-nodule endosymbionts of leguminous plants, also form natural endophytic associations with roots important cereal plants. Despite its widespread occurrence, much remains unknown about colonization cereals by rhizobia. We examined infection, dissemination, and healthy rice plant tissues four species gfp- tagged rhizobia their influence on growth physiology rice. The results indicated a dynamic infection process beginning surface rhizoplane (especially at lateral...
Growth‐promoting diazotrophs can enhance the growth and development of associated crops by transferring fixed N or improving nutrient uptake through modulation hormone‐linked phenomena in inoculated plants. Six rhizobial isolated from a wide range legume hosts were investigated to determine their growth‐promoting activities lowland rice ( Oryza sativa L.) during 1997. Seeds seedlings Pankaj with different rhizobia grown potted soil supplemented varied amounts mineral N. Inoculation Rhizobium...
This paper originates from an address at the 8th International Symposium on Nitrogen Fixation with Non-Legumes, Sydney, NSW, December 2000 summarizes a multinational collaborative project to search for natural, intimate associations between rhizobia and rice (Oryza sativa L.), assess their impact plant growth, exploit those combinations that can enhance grain yield less dependence inputs of nitrogen (N) fertilizer. Diverse, indigenous populations Rhizobium leguminosarum bv. trifolii (the...
ABSTRACT Methanogenic bioreactor communities were used as model ecosystems to evaluate the relationship between functional stability and community structure. Replicated methanogenic with two different structures established. The effect of a substrate loading shock on population dynamics in each microbial was examined by using morphological analysis, small-subunit (SSU) rRNA oligonucleotide probes, amplified ribosomal DNA (rDNA) restriction analysis (ARDRA), partial sequencing SSU rDNA...
ABSTRACT Rhizobia are the common bacterial symbionts that form nitrogen-fixing root nodules in legumes. However, recently other bacteria have been shown to nodulate and fix nitrogen symbiotically with these plants. Neptunia natans is an aquatic legume indigenous tropical subtropical regions African soils nodulated by Allorhizobium undicola. This develops unusual root-nodule symbiosis on floating stems environments through a unique infection process. Here, we analyzed low-molecular-weight RNA...
Rice ( Oryza sativa L.) is one of the world's most important crops. The present investigation was designed to assess range growth‐promoting activities various diazotrophic bacteria on rice seedling vigor, its carryover effect straw and grain yield, persistence an inoculant strain roots under greenhouse conditions. Growth responses inoculation exhibited bacterial strain–rice variety specificity that were either stimulatory or inhibitory. included changes in rates emergence, radical...
Legume plants carefully control the extent of nodulation in response to rhizobial infection. To examine mechanism underlying this process we conducted a detailed analysis Lotus japonicus hypernodulating mutants, har1-1, 2 and 3 that define new locus, HYPERNODULATION ABERRANT ROOT FORMATION (Har1), involved root symbiotic development. Mutations Har1 locus alter architecture by inhibiting elongation, diminishing diameter stimulating lateral initiation. At cellular level these developmental...
The association between grass roots and Azospirillum brasilense Sp 7 was investigated by the Fahraeus slide technique, using nitrogen-free medium. Young inoculated of pearl millet guinea produced more mucilaginous sheath (mucigel), root hairs, lateral than did uninoculated sterile controls. bacteria were found within mucigel that accumulated on cap along axes. Adherent associated with granular material hairs fibrillar undifferentiated epidermal cells. Significantly fewer numbers azospirilla...
Cross-reactive antigens of clover roots and Rhizobium trifolii were detected on their cell surfaces by tube agglutination, immunofluorescent, radioimmunoassay techniques. Anti-clover root antiserum had a higher agglutinating titer with infective strains R. than noninfective strains. The previously adsorbed cells remained reactive only cells, including revertants. When the was neither nor cells. Other species incapable infecting did not demonstrate surface cross-reactive clover....
A detailed microscopical analysis of the morphological features that distinguish different developmental stages nodule organogenesis in wild-type Lotus japonicus ecotype Gifu B-129-S9 plants was performed, to provide necessary framework for evaluation altered phenotypes L. symbiotic mutants. Subsequently, chemical ethyl methanesulfonate (EMS) mutagenesis carried out. The approximately 3,000 M 1 and their progeny yielded 20 stable variants, consisting at least 14 symbiosis-associated loci or...
We used computer-assisted microscopy at single cell resolution to quantify the in situ spatial scale of N-acylhomoserine lactone (AHL)-mediated cell-to-cell communication Pseudomonas putida colonized on tomato and wheat root surfaces. The results this quantification study close-to-natural surfaces challenge conventional view a quorum group requirement high densities for type bacterial communication. In image analysis indicated that effective 'calling distance' was most frequent 4–5 μm,...
A previous analysis showed that Gammaproteobacteria could be the sole recoverable bacteria from surface-sterilized nodules of three wild species Hedysarum. In this study we extended to eight Mediterranean native, uninoculated legumes never previously investigated regarding their root-nodule microsymbionts. The structural organization was studied by light and electron microscopy, bacterial occupants were assessed combined cultural molecular approaches. On examination 100 field-collected...
Quantitative microscope techniques were utilized to examine the adsorption of rhizobial cells clover root hairs. Adsorption noninfective strains Rhizobium trifolii or infective R. meliloti hairs was four five times less than that strains. Attachment rod-shaped bacteria occurred in a polar, end-on fashion. Viable heat-killed precoated with lectin having 2-deoxyglucose specificity had increased roots. roots not if inactivated by heat treatment prior incubation trifolii. inhibited (30 mM) but...
Either NO3− (16 millimolar) or NH4+ (1 completely inhibited infection and nodulation of white clover seedlings (Trifoliin repens) inoculated with Rhizobium trifolii. The binding R. trifolii to root hairs the immunologically detectable levels plant lectin, trifoliin, on hair surface had parallel declining slopes as concentration either was increased in rooting medium. This supports role trifoliin hairs. Agglutination by from seeds not these NH4+. results suggest that fixed N ions may play...
ABSTRACT Parallel processing is more stable than serial in many areas that employ interconnected activities. This hypothesis was tested for microbial community function using two quadruplicate sets of methanogenic communities, each set having substantially different populations. The communities were maintained at a mean cell residence time 16 days and glucose loading rate 0.34 g/liter-day variable-volume reactors. To test stability to perturbation, they subjected an instantaneous pulse...
The involvement of Rhizobium enzymes that degrade plant cell wall polymers has long been an unresolved question about the infection process in root nodule symbiosis. Here we report production from leguminosarum bv. trifolii carboxymethyl cellulose and polypectate model substrates with sensitive methods reliably detect enzyme activities: a double-layer plate assay, quantitation reducing sugars bicinchoninate reagent, activity gel electrophoresis-isoelectric focusing. Both activities were (i)...
The time course and orientation of attachment Rhizobium trifolii 0403 to white clover root hairs was examined in slide cultures by light electron microscopy. Inocula were grown for 5 days on defined BIII agar medium represented the large subpopulation fully encapsulated single cells which uniformly bind lectin trifoliin A. When 10(7) or more added per seedling, bacteria attached within minutes, forming randomly oriented clumps at hair tips. Several hours later, polarly sides hair. This...
The rhizobia-legume, root-nodule symbiosis provides the most efficient source of biologically fixed ammonia fertilizer for agricultural crops. Its development involves pathways specificity, infectivity, and effectivity resulting from expressed traits bacterium host plant. A key event infection process required this is a highly localized, complete erosion plant cell wall through which bacterial symbiont penetrates to establish nitrogen-fixing, intracellular endosymbiotic state within host....
Electron microscope examination of Rhizobium spp. revealed microfibrils produced by flocculating strains but not nonflocculating strains. The from R. trifolii (NA30) were isolated and identified as cellulose enzymatic, X-ray diffraction, infrared spectral analyses. Both infective noninfective flocculated microfibrils. More infection threads observed in clover root hairs growing the presence flocs comparison with where single bacterial cells predominated.