Robert Ridge

Robert Ridge
International Christian University · Graduate School of Arts and Sciences

BA BSc(Hons) PhD

About

62
Publications
3,715
Reads
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1,572
Citations
Introduction
I am retired from academic life due to age restrictions in Japan, and I thus have no access to research facilities. Nevertheless currently finishing a project on gravi-sensing in plants. I now experiment with vegetable growing at my mountain house, in Fujimi, Nagano-prefecture. The property is 1,000m above sea level and very close to the centre of Honshu. The weather is highly variable from year to year, and temperatures range from -15C lows in midwinter to 33C highs in midsummer.
Additional affiliations
April 2016 - present
International Christian University
Position
  • Professor Emeritus
September 1993 - March 2016
International Christian University
Position
  • Professor
September 1993 - present
International Christian University
Position
  • Professor
Description
  • POSTGRAD: PLANT-MICROBE INTERACTIONS, APPROACHES IN EXPERIMENTAL SCIENCE .. UNDERGRAD: FOUNDATION OF BIOLOGY, CELL BIOLOGY, PLANT DEVELOPMENT, LAB IN PLANT STRUCTURE, ADVANCED SEMINAR, LIFE SCIENCE, SEMINAR IN INTERDISCIPLINARY SCIENCE
Education
March 1982 - March 1985
Australian National University
Field of study
  • Genetics
February 1978 - November 1980
February 1975 - November 1977
University of Western Australia
Field of study
  • Geology, Geography

Publications

Publications (62)
Article
Full-text available
Nuclear migration during infection thread (IT) development in root hairs is essential for legume-Rhizobium symbiosis. However, little is known about the relationships between IT formation, nuclear migration, and microtubule dynamics. To this aim, we used transgenic Lotus japonicus expressing a fusion of the green fluorescent protein and tubulin-α6...
Article
Full-text available
The endoplasmic reticulum (ER) of the model legume Lotus japonicus was visualized using green fluorescent protein (GFP) fused with the KDEL sequence to investigate the changes in the root hair cortical ER in the presence or absence of Mesorhizobium loti using live fluorescence imaging. Uninoculated root hairs displayed dynamic forms of ER, ranging...
Article
Type-II, singlet oxygen-mediated photosensitized damage has already been shown to occur in epicotyls of dark-germinated pea (Pisum sativum L.) seedlings upon illumination, resulting in fast turgor loss and wilting. In this study we show evidence that the palette of reactive oxygen species (ROS) is more complex. Hydrogen peroxide, superoxide and hyd...
Article
Full-text available
ENOD40 is one of the most intriguing early nodulin genes that is known to be induced very early in response to interaction of legume plants with symbiotic Rhizobium bacteria, but its function in the nodulation process is still not known. Lotus japonicus has two ENOD40 genes: LjENOD40-1 is abundantly induced in very early stages of bacterial infecti...
Article
Full-text available
Plant cells form a highly dynamic microtubule network organized into different arrays that are essential for many important cellular activities. A key feature of microtubules is their dynamic behaviour in which individual microtubules stochastically switch between periods of growth and disassembly. This feature contributes substantially to the rapi...
Article
Full-text available
The incorporation of a fusion of green fluorescent protein and tubulin-alpha 6 from Arabidopsis thaliana in root hairs of Lotus japonicus has allowed us to visualize and quantify the dynamic parameters of the cortical microtubules in living root hairs. Analysis of individual microtubule turnover in real time showed that only plus polymer ends contr...
Article
Full-text available
Plant myosins are motor proteins that bind to the external surfaces of organelles and interact with the cytoskeletal protein actin (as actin microfilaments), which organizes and directs intracellular movement. Recent progress in physiological, biochemical, immunological, and genetical studies of plant myosin has revealed considerable information ab...
Article
Full-text available
Arabidopsis thaliana plants were stably transformed with DNA encoding green fluorescent protein and with sequences ensuring retention in the endoplasmic reticulum (ER). Confocal laser scanning microscopy shows fluorescent ER in many cells of seedlings so allowing developmental changes to be documented. The arrangement of the cortical ER changes as...
Chapter
Physiological and morphological studies on root hairs trace back to the 18th Century (see Farr 1927a,b,c). The pattern of root hair growth and development is under the influence of various factors including genetic, physiological and environmental factors (see Ridge 1995b; Peterson and Farquhar 1996). Involvement of plant hormones in the control of...
Chapter
Most of the work on this subject is associated with the Rhizobium/legume symbiosis, because the earliest interactions between rhizobia and legume host, at least for many important legume crops, are at the root hair-rhizosphere interface. Despite this, it is surprising that so few laboratories have published in this area of research: the presumed re...
Book
Root hairs are tip-growing cells that originate from epidennal cells called trichoblasts. Their role may be simply thought of as extending the surface area of the root to facilitate absorption of nutrients and water. However, as you will see in this book, the root hair is far more than that. To an increasingly larger number of plant biologists, the...
Article
Full-text available
To determine whether the gusA gene, which encodes β-glucuronidase (GUS) and lacZ gene, which encodes β-galactosidase are suitable for tracing nitrogen-fixing bacteria in the infection process, Bradyrhizobium japonicum strains labelled with each gene were constructed. Both introduced genes were expressed in rhizobia, but it was difficult to specify...
Article
Full-text available
Four legumes and two nonlegumes were investigated for the presence of sugars at the tips of their root hairs, using commercially available lectins which have specific affinities for certain sugars. It was found that while only one lectin (RCA-I, which binds to -D-galactose) bound to narrow-host-range legumes and one nonlegume, five out of ten lecti...
Chapter
The discovery of a freely swimming sperm in Ginkgo biloba at the end of the nineteenth century by Sakugoro Hirase [1–3] was one of the most significant moments in botany, because it led to the establishment of Ginkgo as the true and sole link between the non-flowering primitive plants and the advanced seed plants. Hirase, as both amateur botanist a...
Article
The biological and symbiotic properties of two types of exopolysaccharide deficient (Exophenotype) mutants of Rhizobium leguminosarum were investigated. One mutant, a pss1 derivative (ANU437) of R. l. bv. trifolii, produces very low levels of acidic exopolysaccharide (EPS) and of the acidic oligosaccharide (AOS) repeating unit lacking its O-acetyl...
Article
After freeze-substitution, micro-vesicles were found only in close proximity to the plasma membrane. Macro and pyriform vesicles were found throughout the cytosol, but also ‘packaged’ close to the plasma membrane, the package delineated by electron transparent outlines similar to the endoplasmic reticulum. These outlines appeared to be continuous w...
Article
Recent results in root hair research show that these tip-growing cells are useful models in plant cell biology research. The review covers a range of topics, but there is particular emphasis on the use of mutants in molecular (genetic) analysis.
Article
Cloned DNA fragments coding for the nodDABC genes of Rhizobium leguminosarum biovar trifolii strain ANU843 were introduced into Rhizobium strains possessing Sym plasmid deletions. These strains were able to: (a) synthesise four butanol-soluble Nod metabolites; (b) affect the normal growth pattern of plant root hairs of a wide range of host and non-...
Article
Nodule-like structures were induced on rice varieties Calrose and Pelde using 2,4-dichlorophenoxyacetic acid (2,4-D) in a concentration range of 2.5 × 10-6 M to 1 × 10-5M. The nodule-like structures appeared to result from the fusion of multiple meristems induced in very close proximity to each other. The internal tissue differentiation of some of...
Article
Although the rootcap is required for gravitropic sensing, various classical and contemporary data raise the question of whether additional sensing occurs away from the cap in roots. Roots of Equisetum hyemale L. (horsetail) were examined by light and electron microscopy to determine which cell components were distributed with respect to gravity bot...
Article
Although the rootcap is required for gravitropic sensing, various classical and contemporary data raise the question of whether additional sensing occurs away from the cap in roots. Roots of Equisetum hyemale L. (horsetail) were examined by light and electron microscopy to determine which cell components were distributed with respect to gravity bot...
Article
The addition of the synthetic auxin 2,4-dichlorophenoxyacetic acid (2,4-D) at a concentration range of between 5 × 10-5 M and 1 × 10-6M caused nodule-like outgrowths on wheat seedling roots. Concentrations of 2,4-D greater than this range caused stunting and death, while concentrations less than 1 × 10-7 M had no obvious effect on plant growth. At...
Article
Full-text available
A full-length cDNA clone encoding cytosolic glutamine synthetase (GS), expressed in roots and root nodules of soybean, was isolated by direct complementation of an Escherichia coli gln A- mutant. This sequence is induced in roots by the availability of ammonia. A 3.5-kilobase promoter fragment of a genomic clone (lambda GS15) corresponding to this...
Article
A simple technique and inexpensive apparatus for the rapid-freeze preservation of the single-cell alga Carteria crucifera is described in detail. The results show a complete absence of plasmolysis; a sharply defined, periodically indented plasmalemma; cortical microtubules in close proximity to the plasmalemma; fine structure to dictyosomes in a di...
Article
The leaf anatomy, histochemistry and ultrastructure of the intertidal and subtidal seagrass Zostera muelleri Irmish ex Aschers. from Westernport Bay, Victoria were studied. Unusual anatomical and ultrastructural features are compared with other seagrasses and their functional significance is assessed. Subcuticular cavities are present in the young...
Article
Root hair cytoplasmic microtubules and filamentous actin are known to maintain the location of the nucleus in relation to the hair tip. After cytochalasin-D treatment, fragments of F-actin were found to be closely associated with the nucleus and plastids, and with accumulations of mitochondria, dictyosomes and vesicles. Abnormal wal ingrowths found...
Article
Full-text available
Mutant strain ANU2861, a transposon Tn5 mutant of the fast-growing, broad-host-range Rhizobium strain ANU280 (NGR234 Smr Rfr) overproduces polysaccharide, is an ade auxotroph, and induces poorly developed nodules on Leucaena leucocephala and Lablab purpureus (H.C. Chen, M. Batley, J.W. Redmond, and B.G. Rolfe, J. Plant Physiol. 120:331-349, 1985)....
Article
The freeze-substitution method was applied toVicia hirsuta root hairs to test its effectiveness in improving preservation of the cell ultrastruture. Freeze-substitution almost certainly represents more faithfully the structure of the hair cell. A previously unreported ‘pyriformis’ vesicle is described. Also unique to freeze-substituted material are...
Article
A prominent feature of tip growth in filamentous plant cells is that the nucleus often migrates in step with the tip as it extends. We have studied this long-recognized but unexplained relationship in root hairs of the legume Vicia hirsuta by a variety of microscopic techniques. Using rhodaminyl lysine phallotoxin, and antitubulin antibodies, root...
Article
Full-text available
Ten fluorescein isothiocyanate-labeled lectins were tested on the roots of the tropical legume Macroptilium atropurpureum Urb. Four of these (concanavalin A, peanut agglutinin, Ricinis communis agglutinin I [RCA-I], wheat germ agglutinin) were found to bind to the exterior of root cap cells, the root cap slime, and the channels between epidermal ce...
Article
The infection of the tropical legume Macroptilium atropurpureum Urb. by the broad-host-range, fast-growing Rhizobium ANU240 was studied using a spot-inoculation technique which localised infection events to a < 1 mm zone on the root. It was found that Rhizobium attached to the root surface within minutes of inoculation. By 5–6 h after inoculation t...
Article
A complex, multi-step interaction between the soil bacterium Rhizobium and specific leguminous plants results in the induction of nitrogen-fixing root nodules (Rolfe et al 1981). The bacteria respond to plant-secreted compounds which stimulate the expression of the nodulation genes (Innes et al 1985; Mulligan and Long 1985; Rossen et al 1985). The...
Article
Full-text available
Using a new microinoculation technique, we demonstrated that penetration of Rhizobium sp. into the host root hair cell occurs at 20 to 22 h after inoculation. It did this by dissolving the cell wall maxtrix, leaving a layer of depolymerized wall microfibrils. Colony growth pressure "stretched" the weakened wall, forming a bulge into an interfacial...
Article
Five specific transposon-induced nodulation defective (Nod(-)) mutants from different fast-growing species ofRhizobium were used as the recipients for the transfer of each of several endogenous Sym(biosis) plasmids or for recombinant plasmids that encode early nodulation and host-specificity functions. The Nod(-) mutants were derived fromR. trifoli...
Article
Full-text available
A large Sym plasmid from a fast-growing cowpea Rhizobium species was made mobilizable by cointegration with plasmid pSUP1011, which carries the oriT region of RP4. This mobilizable Sym plasmid was transferred to a number of Rhizobium strains, in which nodulation and nitrogen fixation functions for symbiosis with plants of the cowpea group were expr...
Article
Previous studies have established differences in water relations between the major dominant of the northern jarrah forest, Eucalyptus marginata, which transpires freely except under conditions of extreme drought, and potential replacement species which exhibit some measure of stomatal control. The anatomy of the water-conducting system of three ind...
Article
Land use which reduces tree canopy density and the impact of Phytophthora cinnamomi are believed to be altering the hydrological balance of parts of the northern jarrah forest, Western Australia. In the drier eastern zones of the forest, replacement plant communities must maintain the soil-salt-water balance to prevent significant increases in sali...
Article
The Rhizobium trifolii genes necessary for nodule induction and development have been isolated on a 14.0kb fragment of symbiotic (Sym) plasmid DNA. When cloned into a broad-host-range plasmid vector, these sequences confer a clover nodulation phenotype on a derivative of R. trifolii which has been cured of its endogenous Sym plasmid. Furthermore, t...
Chapter
Certain fast growing strains of Rhizobia, for example strain ORS-571 and strain WE7, are able to induce both stem and root nodules on the tropical legume Sesbania rostrata. Interest in this species centres around its ability to produce spherical nodules which exhibit a very high acetylene reduction ability (Dreyfus and Dommergues 1981). Thus it is...
Chapter
Endogenous Rhizobium plasmids (called Sym plasmids) are thought to encode genes which affect nodulation and host-specificity. Conjugation experiments with various Sym plasmids from R. leguminosarum, R. trifolii and R. meliloti, have resulted in the transfer of host specific nodulation capacity (1, 2). Nod genes located on various Sym plasmids have...
Chapter
Bacteria of the genus Rhizobium interact symbiotically with leguminous plants, forming root nodules in which atmospheric nitrogen is fixed as ammonia. For fast-growing Rhizobium species, this interaction is highly specific: R.trifolii only nodulates clover (Trifolium).
Chapter
The fast-growing cowpea Rhizobium strain NGR234 is able to nodulate a wide range of tropical legumes as well as the non-legume Parasponia (1). Nodulation and structural nitrogenase genes are located on a large Symplasmid in this strain (2). A cryptic megaplasmid of greater than 450 Mdals also exists in NGR234.

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