Publications
| Title | Abstract | Year(sorted ascending) Filter | PMID Filter |
|---|
| nucleotide sequence of an insertion sequence (is) element identified in the t-dna region of a spontaneous variant of the ti-plasmid ptit37. | we have identified and determined the nucleotide sequence of an is element (is136) of agrobacterium tumefaciens. this is the first is element isolated and sequenced from a nopaline type ti-plasmid. our is element has 32/30 bp inverted repeats with 6 mismatches, is 1,313 bp long and generates 9 bp direct repeats upon integration. is136 has 3 main open reading frames (orf's). only orf1 (159 codons) is preceded by sequences that are proposed to serve functional roles in transcriptional and translat ... | 1986 | 3018677 |
| restriction maps and homologies of the three plasmids of agrobacterium rhizogenes strain a4. | agrobacterium rhizogenes strain a4 is a virulent agropine-type strain possessing three plasmids: plasmid a (para4a, 180 kb) is not necessary for plant transformation, plasmid b (250 kb) is the root-inducing plasmid (pria4), and plasmid c (para4c) is a cointegrate of para4a and pria4. the total plasmid dna (para4) of strain a4 was cloned in the cosmid phsg262 and the library obtained was used to establish bamhi maps of the three plasmids. the plasmids a and ri have an apparently identical region ... | 1986 | 3018814 |
| the nodi gene product of rhizobium leguminosarum is closely related to atp-binding bacterial transport proteins; nucleotide sequence analysis of the nodi and nodj genes. | the nucleotide sequence of a 2-kb fragment immediately downstream of the nodabc genes of the rhizobium leguminosarum symbiotic plasmid prl1ji has been determined. genes corresponding to the two open reading frames identified are named nodi and nodj. tn 5 insertions into these genes result in a "nodulation-delayed" phenotype. the predicted amino acid sequence of the nodi gene shows considerable homology to inner-membrane-located gene products involved in active transport systems in escherichia co ... | 1986 | 3019841 |
| location of the right boundary of the virulence region on agrobacterium tumefaciens plasmid ptic58 and a host-specifying gene next to the boundary. | the right boundary of the virulence (vir) region of the nopaline plasmid ptic58 of agrobacterium tumefaciens was determined by transposon insertion, cartridge emplacement, and deletion mutagenesis. genetic complementation with mutant and wild-type alleles led to the identification of the vire locus at the right boundary, which was located about 6 kilobases from the left border of the segment of dna that is transferred into the plant genome. vire is 2.0 kilobases long and encodes at least one pro ... | 1986 | 3019998 |
| genetic manipulations in rhizobium meliloti utilizing two new transposon tn5 derivatives. | two derivatives of the prokaryotic transposon tn5 were constructed in vitro. in tn5-233, the central area of tn5, which carries resistance to kanamycin/neomycin, bleomycin and streptomycin, is replaced by a fragment carrying resistance to the aminocyclitol antibiotics gentamycin/kanamycin and streptomycin/spectinomycin. in tn5-235, the escherichia coli beta-galactosidase gene is inserted within the streptomycin resistance gene of tn5, and constitutively expressed from a tn5 promoter. both constr ... | 1986 | 3020382 |
| nucleotide sequence of rhizobium meliloti rcr2011 genes involved in host specificity of nodulation. | a 6 kb dna segment of the r. meliloti 2011 psym megaplasmid, which contains genes controlling host specificity of root hair infection and of nodulation, was cloned and sequenced. the dna sequence analysis, in conjunction with previous genetic data, allowed identification of four nod genes designated as e, f, g and h. nodh is divergently transcribed with respect to nodfe and nodg. a conserved nucleotide sequence was found around 200 bp upstream of the translation start of nodf, nodh and noda. thi ... | 1986 | 3020515 |
| the vird operon of agrobacterium tumefaciens encodes a site-specific endonuclease. | tumor formation by agrobacterium tumefaciens involves the transfer and integration of a defined segment (t-dna) of tumor-inducing (ti) plasmid dna into the plant nuclear genome. a set of plasmid genes outside the t-dna, the vir genes, are thought to mediate the transfer process. we report here that the vird operon encodes a site-specific endonuclease that cleaves at a unique site within each of the 24 bp direct repeats that flank the t-dna. the endonuclease function was further localized to the ... | 1986 | 3021341 |
| organization of the adenyl cyclase (cya) locus of rhizobium meliloti. | a cya-like gene encoding adenyl cyclase from rhizobium meliloti was localized to a 0.8-kb psti-ecori fragment by subcloning experiments. experiments in escherichia coli 'maxicells' identified a r. meliloti cya gene product of 28 kda, which is significantly smaller than the corresponding protein from enteric bacteria. a control region for the expression of the cya gene in e. coli was found on an adjacent 2.6-kb bglii-bamhi sequence by insertional mutagenesis with tn5 and phage mudi (apr lac). the ... | 1986 | 3021593 |
| a gene essential for agrobacterium virulence is homologous to a family of positive regulatory loci. | the vir region of agrobacterium tumefaciens spans at least six transcriptional loci required for crown gall tumorigenesis. the transcriptional induction of two of these vir loci in response to cocultivation with tobacco suspension cells was measured by using bacteria containing mutations in each of the six vir loci located on the ti plasmid. induction of these vir genes occurred only in bacteria that had functional copies of vira and virg. the nucleic acid sequence of a 1.25-kilobase clone encom ... | 1986 | 3022288 |
| cloning and regulation of erwinia herbicola pigment genes. | the genes coding for yellow pigment production in erwinia herbicola eho10 (atcc 39368) were cloned and localized to a 12.4-kilobase (kb) chromosomal fragment. a 2.3-kb avai deletion in the cloned fragment resulted in the production of a pink-yellow pigment, a possible precursor of the yellow pigment. production of yellow pigment in both e. herbicola eho10 and pigmented escherichia coli clones was inhibited by glucose. when the pigment genes were transformed into a cya (adenylate cyclase) e. coli ... | 1986 | 3023282 |
| assignment of symbiotic developmental phenotypes to common and specific nodulation (nod) genetic loci of rhizobium meliloti. | rhizobium meliloti nodulation (nod) genes required for specific infection and nodulation of alfalfa have been cloned. transposon tn5 mutagenesis defined three nod regions spanning 16 kilobases of the psym megaplasmid. genetic and cytological studies of 62 nodulation-defective mutants allowed the assignment of symbiotic developmental phenotypes to common and specific nod loci. root hair curling was determined by both common (region i) and specific (region iii) nod transcription units; locus iiib ... | 1986 | 3023297 |
| t-dna and opine synthetic loci in tumors incited by agrobacterium tumefaciens a281 on soybean and alfalfa plants. | we report here the molecular characterization of transferred dna (t-dna) in leguminous tumors incited by agrobacterium tumefaciens a281 harboring the tumor-inducing plasmid ptibo542. the t-dna is composed of two regions named tl (left portion)-dna and tr (right portion)-dna, in accordance with the nomenclature for the octopine strains. tl-dna is defined by several internal hindiii restriction fragments totaling 10.8 kilobase pairs (kbp) in uncloned soybean and alfalfa tumors. alfalfa tumor dna m ... | 1986 | 3023301 |
| upstream sequences required for efficient expression of a soybean heat shock gene. | a soybean gene (gmhsp17.5-e) encoding a small heat shock protein was introduced into primary sunflower tumors via t-dna-mediated transformation. rna blot hybridizations and s1-nuclease hybrid protection studies indicated that the heat shock gene containing 3.25 kilobases of 5'-flanking sequences was strongly transcribed in a thermoinducible (40 degrees c) manner. transcriptional induction also occurred to a lesser extent upon treatment of whole tumors with sodium arsenite and cdcl2. basal (26 de ... | 1986 | 3023855 |
| choline kinase ii is present only in nodules that synthesize stable peribacteroid membranes. | host-cell cytoplasm from soybean plants infected with the peribacteroid membrane (pbm)-building rhizobium japonicum strain 61-a-101 (effective, n(2)-fixing) had much higher choline kinase activity than cytoplasm from either uninfected tissue or tissue infected with the non-pbm-building (ineffective, non-n(2)-fixing) strain 61-a-24. ion-exchange chromatography showed that both types of nodule and root tissue possessed constitutive choline kinase i activity that had a k(m) for choline of approxima ... | 1986 | 16593653 |
| conservation of extended promoter regions of nodulation genes in rhizobium. | a 47-base-pair (bp) conserved sequence in the 5'-flanking regions of three transcriptional units coding for nodulation functions (nodabc, nodefg, and nodh) has been identified in rhizobium meliloti strain 41. the conserved region contains subsequences of 7 bp, 5 bp, and 25 bp. the conserved 25-bp sequence was synthesized and used as a hybridization probe; three additional copies of the sequence were identified in r. meliloti 41; all three were localized in the 135-kb nod/nif region of the symbio ... | 1986 | 16593668 |
| bacterial delta-aminolevulinic acid synthase activity is not essential for leghemoglobin formation in the soybean/bradyrhizobium japonicum symbiosis. | previous studies of legume nodules have indicated that formation of the heme moiety of leghemoglobin is a function of the bacterial symbiont. we now show that a hema mutant of bradyrhizobium japonicum that cannot carry out the first step in heme biosynthesis forms fully effective nodules on soybeans. the bacterial mutant strain was constructed by first isolating the wild-type hema gene encoding delta-aminolevulinic acid synthase (ec 2.3.1.37) from a cosmid library, using a fragment of the rhizob ... | 1986 | 16593670 |
| rhizobium meliloti genes required for nodule development are related to chromosomal virulence genes in agrobacterium tumefaciens. | symbiotically essential genes have been identified in rhizobium meliloti that are structurally and functionally related to chromosomal virulence (chv) genes of agrobacterium tumefaciens. homologous sequences also exist in the genomes of other fast-growing rhizobia including rhizobium trifolii, rhizobium leguminosarum, and rhizobium phaseoli. in agrobacterium, the chva and chvb loci are known to be essential for oncogenic transformation of dicotyledonous plants and for attachment to plant cells [ ... | 1986 | 16593714 |
| expression of the nodulation gene noda in rhizobium meliloti and localization of the gene product in the cytosol. | the noda gene of rhizobium meliloti encodes a 21.8-kda protein, which is conserved in several rhizobium species. we overproduced the noda protein as a fusion product with a portion of the lambda ci repressor in escherichia coli. this fusion protein was purified from inclusion bodies by gel and hydroxyapatite chromatography in the presence of nadodso(4). monospecific polyclonal antibodies against the hybrid protein were used to detect the noda protein in the cytosol of e. coli and r. meliloti by ... | 1986 | 16593791 |
| differential reaction of alfalfa cultivars to meloidogyne hapla and m. chitwoodi populations. | meloidogyne hapla reproduced and suppressed growth (p < 0.05) of susceptible lahontan and moapa alfalfa at 15, 20, and 25 c. at 30 c, resistant nevada syn xx lost resistance to m. hapla. m. hapla invaded and reproduced on rhizobium meliloti nodules of lahontan and moapa, inducing giant cell formation and structural disorder of vascular bundles of nodules without disrupting bacteroids. at 15, 20, and 25 c a m. chitwoodi population from utah reproduced on lahontan, moapa, and nevada syn xx alfalfa ... | 1986 | 19294189 |
| overdrive, a t-dna transmission enhancer on the a. tumefaciens tumour-inducing plasmid. | during crown gall tumorigenesis a specific segment of the agrobacterium tumefaciens tumour-inducing (ti) plasmid, the t-dna, integrates into plant nuclear dna. similar 23-bp direct repeats at each end of the t region signal t-dna borders, and t-dna transmission (transfer and integration) requires the right-hand direct repeat. a chemically synthesized right border repeat in its wild-type orientation promotes t-dna transmission at a low frequency; ti plasmid sequences which normally flank the righ ... | 1986 | 15966101 |
| the pleiotropic nature of symbiotic regulatory mutants: bradyrhizobium japonicum nifa gene is involved in control of nif gene expression and formation of determinate symbiosis. | in the slow-growing soybean symbiont, bradyrhizobium japonicum (strain 110), a nifa-like regulatory gene was located immediately upstream of the previously mapped fixa gene. by interspecies hybridization and partial dna sequencing the gene was found to be homologous to nifa from klebsiella pneumoniae and rhizobium meliloti, and to a lesser extent, also to ntrc from k. pneumoniae. the b. japonicum nifa gene product was shown to activate b. japonicum and k. pneumoniae nif promoters (using nif::lac ... | 1986 | 15966104 |
| transposon mutagenesis and excision of r' plasmids by conjugative, chimeric plasmid puw942 in extra-slow-growing rhizobium japonicum strains. | transposons tn501 (specifying mercury resistance) and tn7 (specifying resistance to trimethoprim and streptomycin) were introduced into extra-slow-growing rhizobium japonicum by conjugal transfer of the 82 kilobase chimeric plasmid puw942. mercury-resistant transconjugants were obtained at a frequency of 10 to 10. the transfer frequency of streptomycin resistance was lower than that of mercury resistance, and tn7 was relatively unstable. puw942 was not maintained as an autonomously replicating p ... | 1986 | 16346976 |
| lectin binding to the root and root hair tips of the tropical legume macroptilium atropurpureum urb. | 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 cells in the root elongation zone. one of these lectins, rca-i, bound to the root hair tips in the mature and emerging hair zones and also to sites at w ... | 1986 | 16346989 |
| rhizobins, a group of peptides in the free-amino-acid pool of the soybean-rhizobium system. | free-living rhizobium (according to bergey's manual of systematic bacteriology, [1984, the williams & wilkins co., baltimore], bradyrhizobium) japonicum was found to release a peptide into the nutrient media. soybean nodules contained this peptide and exuded it into the soil. the name "rhizobin a" is suggested for this peptide. nodules also contained another peptide, rhizobin b, as well as an unidentified, ninhydrin-positive compound, rhizobin c. the three peptides were confined to the free-amin ... | 1986 | 16347004 |
| asymbiotic acetylene reduction by a fast-growing cowpea rhizobium strain with nitrogenase structural genes located on a symbiotic plasmid. | a procedure was designed which enabled the detection of ex planta nitrogenase activity in the fast-growing cowpea rhizobium strain ihp100. nitrogenase activity in agar culture under air occurred at a rate similar to that found for bradyrhizobium strain cb756 but lower than that for rhizobium strain ors571. hybridization studies showed that both nod and nif genes were located on a 410-kilobase sym plasmid in strain ihp100. | 1986 | 16347045 |
| inoculation response of legumes in relation to the number and effectiveness of indigenous rhizobium populations. | the response of legumes to inoculation with rhizobia can be affected by many factors. little work has been undertaken to examine how indigenous populations or rhizobia affect this response. we conducted a series of inoculation trials in four hawaiian soils with six legume species (glycine max, vigna unguiculata, phaseolus lunatus, leucaena leucocephala, arachis hypogaea, and phaseolus vulgaris) and characterized the native rhizobial populations for each species in terms of the number and effecti ... | 1986 | 16347046 |
| influence of location, host cultivar, and inoculation on the composition of naturalized populations of rhizobium meliloti in medicago sativa nodules. | a phage typing system was used to evaluate the composition of indigenous populations of rhizobium meliloti inhabiting nodules of medicago sativa cultivars grown with and without inoculation at two field sites during 1983 and 1984. soil at both locations contained established populations of r. meliloti at planting. analysis of 1,920 nodule isolates revealed 55 unique phage types of indigenous r. meliloti at one site and 65 indigenous types at the other location. the distributions of phage types d ... | 1986 | 16347054 |
| analysis of rhizobium meliloti sym mutants obtained by heat treatment. | deletions in the psym megaplasmid of rhizobium meliloti were produced at a high frequency, and their lengths varied according to incubation temperature. morphological differentiation into large and small colonies occurred after heat treatment. small colonies elicited pseudonodules on alfalfa roots. | 1986 | 16347063 |
| symbiotic effectiveness and host-strain interactions of rhizobium fredii usda 191 on different soybean cultivars. | nodulation, acetylene reduction activity, dry matter accumulation, and total nitrogen accumulation by nodulated plants growing in a nitrogen-free culture system were used to compare the symbiotic effectiveness of the fast-growing rhizobium fredii usda 191 with that of the slow-growing bradyrhizobium japonicum usda 110 in symbiosis with five soybean (glycine max (l.) merr.) cultivars. measurement of the amount of nitrogen accumulated during a 20-day period of vegetative growth (28 to 48 days afte ... | 1986 | 16347066 |
| production and use of monoclonal antibodies for identification of strains of rhizobium trifolii. | we produced a monoclonal antibody against rhizobium trifolii 162x95. this antibody in cell culture supernatant was used in an indirect enzyme-linked immunosorbent assay to differentiate strain 162x95 from naturalized strains in the appalachian region. nodules crushed in 0.1 to 0.2 ml of phosphate-buffered saline and used to charge enzyme-linked immunosorbent assay plates gave strong absorbance readings. heat-inactivated and noninactivated portions of 162x95 cultures were strongly reactive, indic ... | 1986 | 16347098 |
| role of pili (fimbriae) in attachment of bradyrhizobium japonicum to soybean roots. | pili (fimbriae) were observed on cells of each of the five strains of bradyrhizobium japonicum and the one strain of rhizobium trifolii examined. pili on b. japonicum were about 4 nm in diameter and polarly expressed. piliated cells were estimated by transmission electron microscopy and hydrophobic attachment to polystyrene to constitute only a small percentage of the total population. the proportion of piliated cells in these populations was dependent on culture age in some strains. piliated b. ... | 1986 | 16347100 |
| quantitation of adsorption of rhizobia in low numbers to small legume roots. | bacteria adsorbed in low numbers to alfalfa or clover root surfaces were counted after incubation of seedlings in mineral solution with very dilute inocula (less than 10 bacteria per ml) of an antibiotic-resistant strain under defined conditions. after specified washing, bacteria which remained adsorbed to roots were selectively quantitated by culturing the roots embedded in yeast extract-mannitol-antibiotic agar and counting the microcolonies along the root surface; the range was from about 1 b ... | 1986 | 16347137 |
| host-symbiont specificity expressed during early adsorption of rhizobium meliloti to the root surface of alfalfa. | early (4 h) adsorption of rhizobium meliloti l5-30 in low numbers to alfalfa roots in mineral solution was examined for competition with other bacterial strains. all tested competitor strains decreased the adsorption of l5-30 by extents which depended on the strain and its concentration. the decrease of adsorption by r. meliloti competitors (all of them infective in alfalfa) was nearly complete at saturation (97 to 99% decrease). all other heterologous rhizobia and agrobacterium tumefaciens at s ... | 1986 | 16347138 |
| bacterial growth rates and competition affect nodulation and root colonization by rhizobium meliloti. | the addition of streptomycin to nonsterile soil suppressed the numbers of bacterial cells in the rhizosphere of alfalfa (medicago sativa l.) for several days, resulted in the enhanced growth of a streptomycin-resistant strain of rhizobium meliloti, and increased the numbers of nodules on the alfalfa roots. a bacterial mixture inoculated into sterile soil inhibited the colonization of alfalfa roots by r. meliloti, caused a diminution in the number of nodules, and reduced plant growth. enterobacte ... | 1986 | 16347173 |
| large-scale production of rhizobium meliloti on whey. | whey, a by-product of the cheese industry, can sustain the growth of fast-growing rhizobia. to avoid any latency of growth, rhizobial inoculum must be prepared under inducing conditions. in unsupplemented whey, the number of cells of rhizobium meliloti balsac reached 5 x 10 cfu/ml in 48 h of incubation. this is comparable to the yield obtained with yeast-mannitol broth, the standard medium for the growth of rhizobia. in raw whey supplemented with yeast extract (1.0 g/liter) and phosphate (0.5 g/ ... | 1986 | 16347176 |
| growth of fast- and slow-growing rhizobia on ethanol. | free-living soybean rhizobia and bradyrhizobium spp. (lupine) have the ability to catabolize ethanol. of the 30 strains of rhizobia examined, only the fast- and slow-growing soybean rhizobia and the slow-growing bradyrhizobium sp. (lupine) were capable of using ethanol as a sole source of carbon and energy for growth. two strains from each of the other rhizobium species examined (r. meliloti, r. loti, and r. leguminosarum biovars phaseoli, trifolii, and viceae) failed to grow on ethanol. one rhi ... | 1986 | 16347190 |
| semienclosed tube cultures of bean plants (phaseolus vulgaris l.) for enumeration of rhizobium phaseoli by the most-probable-number technique. | the semienclosed tube culture technique of gibson was modified to permit growth of common bean (phaseolus vulgaris l.) roots in humid air, enabling enumeration of the homologous (nodule forming) symbiont, rhizobium phaseoli, by the most-probable-number plant infection method. a bean genotype with improved nodulation characteristics was used as the plant host. this method of enumeration was accurate when tubes were scored 3 weeks after inoculation with several r. phaseoli strains diluted from aqu ... | 1986 | 16347191 |
| autecology in rhizospheres and nodulating behavior of indigenous rhizobium trifolii. | indigenous serotype 1-01 of rhizobium trifolii occupied significantly fewer nodules (6%) on plants of soil-grown noninoculated subterranean clover (trifolium subterraneum l.) cv. woogenellup than on cv. mt. barker (36%) sampled at the flowering stage of growth. occupancy by indigenous serotype 2-01, was not significantly different on the two cultivars (16 and 26%). serotype-specific, fluorescent-antibody conjugates were synthesized and used to enumerate the indigenous serotypes in host (clovers) ... | 1986 | 16347198 |
| interstrain competition between representatives of indigenous serotypes of rhizobium trifolii. | the symbiotic characteristics of rhizobium trifolii strains 1-01 and 2-01 were evaluated both individually and in various combinations on two cultivars (mt. barker and woogenellup) of subterranean clover (trifolium subterraneum l.). nodules were observed on day 8 independent of cultivar or strain. cultivar differences were measured in nodulating efficiency by 1-01 since 54% of the primary nodules were formed on cv. mt. barker and only 15% were formed on cv. woogenellup in the zone above, or 1 cm ... | 1986 | 16347199 |
| rhizobium trifolii 0403 is capable of growth in the absence of combined nitrogen. | rhizobium trifolii 0403 was treated with 16.6 mm succinate and other nutrients and thereby induced to grow in nitrogen-free medium. the organism grew microaerophilically on either semisolid or liquid medium, fixing atmospheric nitrogen to meet metabolic needs. nitrogen fixation was measured via n incorporation (18% n enrichment in 1.5 doublings) and acetylene reduction. nitrogen-fixing cells had a k(m) for acetylene of 0.07 atm (ca. 7.09 kpa), required about 3% oxygen for optimum growth in liqui ... | 1986 | 16347203 |
| distribution of hydrogen-metabolizing bacteria in alfalfa field soil. | h(2) evolved by alfalfa root nodules during the process of n(2) fixation may be an important factor influencing the distribution of soil bacteria. to test this hypothesis under field conditions, over 700 bacterial isolates were obtained from fallow soil or from the 3-mm layer of soil surrounding alfalfa (medicago sativa l.) root nodules, alfalfa roots, or bindweed (convolvulus arvensis l.) roots. bacteria were isolated under either aerobic or microaerophilic conditions and were tested for their ... | 1986 | 16347207 |
| symbiotic characteristics and rhizobium requirements of a leucaena leucocephala x leucaena diversifolia hybrid and its parental genotypes. | in 56-day-old plants, leucaena leucocephala and its hybrid with l. diversifolia showed 100% more total n than did l. diversifolia. significant (p < 0.01) host-inoculation interaction in total n was 14.4% of the total phenotypic variation. the most effective and competitive rhizobium sp. for the leucaenas was tal 1145. three-strain mixed inoculation was inferior to tal 1145 alone. | 1986 | 16347248 |
| a structural comparison of the acidic extracellular polysaccharides from rhizobium trifolii mutants affected in root hair infection. | the structures of the acidic extracellular polysaccharides (epss) from several r. trifolii mutants were compared by examining their compositions and their sugar linkages as determined by methylation analysis. these mutant strains were derived from the wild-type r. trifolii anu843 and were unable to induce normal root hair curling (hac- phenotype) or nodulation response (nod- phenotype) in clover plants. these strains included several transposon tn5-induced nod-mutants, strain anu871, which posse ... | 1986 | 16664568 |
| carbon and nitrogen assimilation and partitioning in soybeans exposed to low root temperatures. | low root temperature effects on vegetative growth of soybean (harosoy 63 x rhizobium japonicum usda 16) were examined in 35 day old plants exposed to temperatures of 15 degrees c (shoots at 25 degrees c) for an 11 day period. duing this period various aspects of c and n assimilation and partitioning were monitored including shoot night and nodulated root respiration, c and n partitioning to six plant parts, c(2)h(2) reduction, h(2) evolution, leaf area, transpiration, net photosynthesis, and n(2 ... | 1986 | 16664592 |
| enzymes of ammonia assimilation and ureide biosynthesis in soybean nodules: effect of nitrate. | the effect of nitrate on n(2) fixation and the assimilation of fixed n(2) in legume nodules was investigated by supplying nitrate to well established soybean (glycine max l. merr. cv bragg)-rhizobium japonicum (strain 3i1b110) symbioses. three different techniques, acetylene reduction, (15)n(2) fixation and relative abundance of ureides ([ureides/(ureides + nitrate + alpha-amino nitrogen)] x 100) in xylem exudate, gave similar results for the effect of nitrate on n(2) fixation by nodulated roots ... | 1986 | 16664678 |
| the role of dark carbon dioxide fixation in root nodules of soybean. | the magnitude and role of dark co(2) fixation were examined in nodules of intact soybean plants (harosoy 63 x rhizobium japonicum strain usda 16). the estimated rate of nodule dark co(2) fixation, based on a 2 minute pulse-feed with (14)co(2) under saturating conditions, was 102 micromoles per gram dry weight per hour. this was equivalent to 14% of net nodule respiration. only 18% of this co(2) fixation was estimated to be required for organic and amino acid synthesis for growth and export proce ... | 1986 | 16664774 |
| stimulation of nodulation in the clover-rhizobium trifolii 0403 system by penicillin and mecillinam. | the number of nodules produced per clover seedling inoculated with rhizobium trifolii 0403 can be increased almost 2-fold by the addition of penicillin or mecillinam. two-day-old dutch white clover seedlings grown in 250 milliliter boston round jars containing agar-solidified plant growth medium were inoculated with exponentially growing rhizobium trifolii 0403 cells. penicillin or mecillinam (100 micrograms per milliliter) were added immediately or after 24 hours. following 42 days growth, 10 r ... | 1986 | 16664802 |
| two indirect methods for detecting ureide synthesis by nodulated legumes. | two methods were developed for the detection of altered ureide metabolism in legume nodules. both techniques are based on the positive correlation between the presence of high xanthine dehydrogenase (ec 1.2.1.37) specific activity in nodules and the ability of those nodules to produce the ureides, allantoin and allantoic acid. in the first method, nodulated legumes are treated for 2 weeks with a soil drench of allopurinol. after allopurinol treatment, leaves of n(2)-fed, ureide-producing legumes ... | 1986 | 16664857 |
| the relationship between h(2) evolution and acetylene reduction in pisum sativum-rhizobium leguminosarum symbioses differing in uptake hydrogenase activity. | peas (pisum sativum l.) were inoculated with strains of rhizobium leguminosarum having different levels of uptake hydrogenase (hup) activity and were grown in sterile leonard jars under controlled conditions. rates of h(2) evolution and acetylene reduction were determined for intact nodulated roots at intervals after the onset of darkness or after removal of the shoots. hup activity was estimated using treatment plants or equivalent plants from the growth chamber, by measuring the uptake of h(2) ... | 1986 | 16664984 |
| sodium stimulation of uptake hydrogenase activity in symbiotic rhizobium. | initial observations showed a 100% increase in h(2)-uptake (hup) activity of rhizobium leguminosarum strain 3855 in pea root nodules (pisum sativum l. cv alaska) on plants growing in a baked clay substrate relative to those growing in vermiculite, and an investigation of nutrient factors responsible for the phenomenon was initiated. significantly greater hup activity was first measured in the clay-grown plants 24 days after germination, and higher activity was maintained relative to the vermicul ... | 1986 | 16665057 |
| regulation of the soybean-rhizobium nodule symbiosis by shoot and root factors. | the availability of soybean mutants with altered symbiotic properties allowed an investigation of the shoot or root control of the relevant phenotype. by means of grafts between these mutants and wild-type plants (cultivar bragg and williams), we demonstrated that supernodulation as well as hypernodulation (nitrate tolerance in nodulation and lack of autoregulation) is shoot controlled in two mutants (nts382 and nts1116) belonging most likely to two separate complementation groups. the supernodu ... | 1986 | 16665072 |
| compatible and incompatible rhizobia alter membrane potentials of soybean root cells. | inoculation with rhizobium japonicum or r. meliloti reduced the electrical transmembrane potential (e(m)) of soybean (glycine max [l.] merr.) root cells within 1 day. the response could be attributed to altered diffusion potential (e(d)). e(m) values return to control levels by the second day after inoculation, but again were reduced in r. meliloti-inoculated tissue on the seventh day. increased concentrations of sodium phosphate in the perfusion solution magnified the effects of inoculation on ... | 1986 | 16665143 |
| some enzymes of hydrogen peroxide metabolism in leaves and root nodules of medicago sativa. | leaves and nodules (bacteroids and cytosol) of alfalfa (medicago sativa l. cv aragon) plants inoculated with rhizobium meliloti strain 102f51 have been analyzed for the presence of the enzymes superoxide dismutase (sod, ec 1.15.1.1), catalase (ec 1.11.1.6), and peroxidase (ec 1.11.1.7). all three fractions investigated (leaves, bacteroids, and nodular cytosol) show cu,zn-sod activity. besides, the bacteroids and cytosol of nodules possess cn(-)-insensitive sod activities. studies of sod inactiva ... | 1986 | 16665158 |
| expression of nodule-specific uricase in soybean callus tissue is regulated by oxygen. | in soybean root nodules the enzyme uricase is expressed concomitantly with nodule development. the initial expression of this protein does not depend on active nitrogen fixation, as demonstrated by analysis of uricase activity in effective and ineffective root nodules. however, the maximal level of uricase activity is determined by the infecting rhizobium japonicum strain. sterile root cultures and callus tissue, devoid of the microsymbiont, were incubated at varying oxygen concentrations and an ... | 1986 | 16453663 |
| the rhizobium leguminosarum nodulation gene nodf encodes a polypeptide similar to acyl-carrier protein and is regulated by nodd plus a factor in pea root exudate. | the dna sequence of approximately 3.5 kb of the nodulation (nod) region of the rhizobium leguminosarum symbiotic plasmid prl1ji was determined. three open reading frames were identified; genes corresponding to these have been called nodd, node and nodf.nodd is adjacent to noda and is transcribed in the opposite direction. the nodf and node genes are downstream of, and transcribed in the same direction as, nodd with 667 nucleotides between nodd and nodf and three nucleotides separating nodf and n ... | 1986 | 16453679 |
| host-specific regulation of nodulation genes in rhizobium is mediated by a plant-signal, interacting with the nodd gene product. | we have identified a nodd gene from the wide host-range rhizobium strain mpik3030 (termed nodd1) which is essential for nodulation on macroptilium atropurpureum (siratro). experiments with noda-lacz gene fusions demonstrate that the mpik3030 nodd1 regulates expression of the nodabc genes. additionally, we used nodc-lacz fusions of rhizobium meliloti to show that the mpik3030 nodd1 gene induces expression of these fusions by interacting with plant factors from siratro and from the non-host medica ... | 1987 | 16453758 |
| glutamine synthetase genes are regulated by ammonia provided externally or by symbiotic nitrogen fixation. | glutamine synthetase is the key enzyme in the assimilation by plants of reduced nitrogen provided from either the soil or fixed symbiotically in association with rhizobium. we have isolated a number of cdna clones for soybean glutamine synthetase (gs) from a nodule-cdna library, using rna from polysomes immunoprecipitated by gs antibodies. transcripts corresponding to two clones differing in their 3' non-translated sequences were present in both root and nodule tissue; however, the concentration ... | 1987 | 16453762 |
| clovers secrete specific phenolic compounds which either stimulate or repress nod gene expression in rhizobium trifolii. | rhizobium trifolii mutants containing escherichia coli lac gene fusions to specific nodulation (nod) genes were used to characterise phenolic compounds secreted from the roots of white clover (trifolium repens) plants. these compounds either had stimulatory or inhibitory effects upon the induction of the nod genes. the stimulatory compounds were hydroxylated flavones and the most active compound was 7,4'-dihydroxyflavone. the inhibitory compounds present in white clover root exudates were umbell ... | 1987 | 16453763 |
| the isolation and partial characterization of the lipopolysaccharides from several rhizobium trifolii mutants affected in root hair infection. | the lipopolysaccharides (lpss) from rhizobium trifolii anu843 and several transposon (tn5) symbiotic mutants derived from anu843 were isolated and partially characterized. the mutant strains are unable to induce normal root hair curling (hac- phenotype) or nodulation (nod-phenotype) in clover plants. the lpss from the parent and mutants are very similar in composition. analysis by page shows that the lpss consist of higher and lower molecular weight forms. the higher molecular weight form of the ... | 1987 | 16665455 |
| nitrogenase activity in trifolium subterraneum l. in relation to the uptake of nitrate ions. | an experiment was conducted to test the hypothesis that, when nitrogenase and nitrate reductase both contribute to the nitrogen nutrition of a nodulated legume, nitrogenase activity is inversely proportional to the rate of accumulation of organic nitrogen derived from the reduction of nitrate. trifolium subterraneum l. plants, inoculated with rhizobium trifolii and sown as small swards, were allowed to establish a closed canopy and steady rates of growth, dinitrogen fixation, and nitrogen accumu ... | 1987 | 16665549 |
| flavone limitations to root nodulation and symbiotic nitrogen fixation in alfalfa. | transcription of the nodabc genes in rhizobium meliloti is required for root nodule formation in alfalfa (medicago sativa l.) and occurs when specific compounds, such as the flavone luteolin, are supplied by the host plant. results reported here indicate how luteolin in the root and rhizosphere can affect subsequent n(2) fixation and plant growth. previous experiments with ;hairy peruvian 32' (hp32), an alfalfa population produced from ;hairy peruvian' (hp) by two generations of selection for in ... | 1987 | 16665583 |
| gabaculine inhibition of chlorophyll biosynthesis and nodulation in phaseolus lunatus l. | gabaculine (3-amino-2,3-dihydrobenzoic acid) was an inhibitor of in vivo chlorophyll biosynthesis in lima bean (phaseolus lunatus l. cv henderson). when applied to roots of 9-day-old plants, 10 micromolar gabaculine was sufficient to terminate biosynthesis of new chlorophyll. the trifoliolate leaves which emerged after gabaculine treatment were yellow. gabaculine-treated plants had slightly lower dry weights; yet, overall plant size showed very little change. chlorophyll fluorescence induction k ... | 1987 | 16665603 |
| regulation of nodulation in the soybean-rhizobium symbiosis : strain and cultivar variability. | double inoculation (15 h apart) of the soybean cultivar williams with bradyrhizobium japonicum i-110ars reveals a rapid regulatory plant response that inhibits nodulation of distal portions of the primary root (m pierce, wd bauer 1984 plant physiol 73: 286-290). only living, homologous rhizobia elicit the response. we conducted similar double inoculation experiments to test the hypothesis that this is a universal phenomenon in soybean symbioses. we investigated interactions of the cultivar mccal ... | 1987 | 16665616 |
| glycine-glomus-rhizobium symbiosis: v. effects of mycorrhiza on nodule activity and transpiration in soybeans under drought stress. | soybean (glycine max [l.] merr.) plants were nodulated (bradyrhizobium japonicum) and either inoculated with the vesicular-arbuscular mycorrhizal (vam) fungus glomus mosseae (nicol. & gerd.) gerd. and trappe or left uncolonized. all plants were grown unstressed for 21 days initially. after this period, some vam and non-vam plants were exposed to four 8-day drought cycles while others were kept well watered. drought cycles were terminated by rewatering when soil moisture potentials reached -1.2 m ... | 1987 | 16665641 |
| glycine-glomus-rhizobium symbiosis : vi. photosynthesis in nodulated, mycorrhizal, or n- and p-fertilized soybean plants. | soybean (glycine max [l.] merr. cv hobbit) plants were grown in a growth chamber for 56 days in a phosphorus- and nitrogen-deficient soil and were colonized by the vesicular-arbuscular mycorrhizal (vam) fungus glomus mosseae (nicol. & gerd) gerd. and trappe and rhizobium japonicum strain usda 136, or by either organism alone, or by neither. non-vam plants received supplemental phosphorus and nonnodulated plants supplemental nitrogen to achieve the same rate of growth in all treatments. plants of ... | 1987 | 16665642 |
| trifolitoxin production and nodulation are necessary for the expression of superior nodulation competitiveness by rhizobium leguminosarum bv. trifolii strain t24 on clover. | rhizobium leguminosarum bv. trifolii t24 is ineffective in symbiotic nitrogen fixation, produces a potent antibiotic (referred to here as trifolitoxin) that is bacteriostatic to certain rhizobium strains, and is very competitive for clover root nodulation (ea schwinghamer, rp belkengren 1968 arch mikrobiol 64: 130-145). the primary objective of this work was to demonstrate the roles of nodulation and trifolitoxin production in the expression of nodulation competitiveness by t24. unlike wildtype ... | 1987 | 16665698 |
| effect of nitrate on the organic acid and amino acid composition of legume nodules. | nitrate supplied to legume plants inhibits the activity of nitrogenase in rhizobium bacteroids in root nodules. the accumulation of amino n which is known to occur in glycine max (l.) merr. nodules as nitrogenase activity declines was studied in more detail by analysis of changes in free amino acid composition in response to high nitrate supply. a 6-fold increase in asparagine concentration in bradyrhizobium japonicum bacteroids was found about the time of maximum nitrogenase inhibition. however ... | 1987 | 16665775 |
| rhizobium population genetics: enzyme polymorphism in rhizobium leguminosarum from plants and soil in a pea crop. | a population of rhizobium leguminosarum biovar viceae symbiotic on the roots of a commercial pea (pisum sativum cv. maro) crop was sampled by extracting a total of 249 isolates from root nodules on nine plants. another 104 isolates were obtained by using soil from the same site to inoculate test plants, and a further 86 isolates were similarly obtained from soil 20 m distant within the crop. each isolate was characterized for mobility variants of the enzymes glucose-6-phosphate dehydrogenase, su ... | 1987 | 16347287 |
| transposon mutagenesis of azospirillum brasilense and azospirillum lipoferum: physical analysis of tn5 and tn5-mob insertion mutants. | tn5-induced insertion mutants were generated in azospirillum brasilense sp7 and a. lipoferum spbr17 by mating with escherichia coli strains carrying suicide plasmid vectors. the sources of tn5 were the suicide plasmids pgs9 and psup2021. kanamycin-resistant azospirillum colonies appeared from crosses with e. coli at maximum frequencies of 10 per recipient cell. transposon tn5 also conferred streptomycin resistance on azospirillum colonies as was observed earlier for rhizobium sp. eight tn5-induc ... | 1987 | 16347289 |
| symbiotic expression of cosmid-borne bradyrhizobium japonicum hydrogenase genes. | the expression of cosmid-borne bradyrhizobium japonicum hydrogenase genes in alfalfa, clover, and soybean nodules harboring rhizobium transconjugants was studied. cosmid phu52 conferred hydrogen uptake (hup) activity in both free-living bacteria and in nodules on the different plant hosts, although in nodules the instability of the cosmid resulted in low levels of hup activity. in contrast, cosmid phu1, which does not confer hup activity on free-living bacteria, gave a hup phenotype in nodules o ... | 1987 | 16347291 |
| influence of soil and nonsoil environments on nodulation by rhizobium trifolii. | indigenous serotypes 1-01 and 2-02 of rhizobium trifolii occupied similar percentages (18 to 23%) of root nodules on soil-grown subclover (trifolium subterraneum l.) and were virtually absent (4.5%) from nodules of soil-grown white clover (trifolium repens l.). in contrast (with the exception of one dilution [10]), serotype 1-01 occupied a substantial portion of nodules (16 to 40%) on white clover seedlings grown on mineral salts agar and exposed to samples of the same soil in the form of a 10-f ... | 1987 | 16347307 |
| environmental factors influencing numbers of rhizobium leguminosarum biovar trifolii and its bacteriophages in two field soils. | fluctuations in numbers of rhizobium leguminosarum biovar trifolii and its bacteriophages in two fields with different soil types were followed during a 17-month period in 1981 and 1982. mean levels of both phage and rhizobia varied significantly (p < 0.05) on different occasions, with rhizobial levels varying from 1.6 x 10 to 2.0 x 10 cell per g of soil and phage from 0 to 1.7 x 10 pfu/g of soil. multivariate regression analysis showed rhizobial levels to be significantly and positively related ... | 1987 | 16347339 |
| nitrous oxide reduction in nodules: denitrification or n(2) fixation? | detached cowpea nodules that contained a nitrous oxide reductase-positive (nor) rhizobium strain (8a55) and a nitrous oxide reductase-negative (nor) rhizobium strain (32h1) were incubated with 1% n(2)o (95 atom% n) in the following three atmospheres: (i) aerobic with c(2)h(2) (10%), (ii) aerobic without c(2)h(2), and (iii) anaerobic (argon atmosphere) without c(2)h(2). the greatest production of n(2) occurred anaerobically with 8a55, yet very little was formed with 32h1. although acetylene reduc ... | 1987 | 16347344 |
| split-root assays using trifolium subterraneum show that rhizobium infection induces a systemic response that can inhibit nodulation of another invasive rhizobium strain. | subterranean clover plants possessing two equally infectible and robust lateral root systems ("split roots") were used in conjunction with several specific mutant strains (derived from rhizobium trifolii anu843) to investigate a systemic plant response induced by infective rhizobium strains. this plant response controls and inhibits subsequent nodulation on the plant. when strain anu843 was inoculated onto both root systems simultaneously or 24, 48, 72, or 96 h apart, an inhibitory response occu ... | 1987 | 16347390 |
| identification of lotus rhizobia by direct dna hybridization of crushed root nodules. | hybridization of crushed lotus pedunculatus root nodules with p-labeled total genomic dna probes was used to identify rhizobium loti and bradyrhizobium sp. (lotus rhizobia). probes always hybridized with homologous target dna and frequently with dnas of other strains from the same genus. intergeneric hybridization did not occur. results were comparable to those from colony hybridization. | 1987 | 16347400 |
| serological relatedness of rhizobium fredii to other rhizobia and to the bradyrhizobia. | several isolates of rhizobium fredii were examined for their serological relatedness to each other, to bradyrhizobium japonicum, and to other fast- and slow-growing rhizobia. immunofluorescence, agglutination, and immunodiffusion analyses indicated that r. fredii contains at least three separate somatic serogroups, usda 192, usda 194, and usda 205. there was no cross-reaction between any of the r. fredii isolates and 13 of the 14 b. japonicum somatic serogroups tested. cross-reactions were obtai ... | 1987 | 16347404 |
| increased effectiveness of competitive rhizobium strains upon inoculation of cajanus cajan. | a field study was conducted in lysimeters containing n-enriched soil to determine the effects of four competitive rhizobium strains upon yield parameters of pigeon peas (cajanus cajan). the greatest differences observed were in seed yields; strain p132 effected the highest seed yield (121 +/- 20 g per plant), and the control strain (indigenous rhizobia) effected the lowest yield (43.9 +/- 8 g per plant). with the exception of seeds and pods, the dry matter weights were not different. although th ... | 1987 | 16347429 |
| influence of lime and phosphate on nodulation of soil-grown trifolium subterraneum l. by indigenous rhizobium trifolii. | previous research had identified four serogroups of rhizobium trifolii indigenous to the acidic abiqua soil (fine, mixed, mesic cumulic ultic haploxeroll). nodulation of subterranean clover (trifolium subterraneum l.) by two of the serogroups, 6 and 36, was differentially influenced by an application of caco(3) which raised the ph of the soil from 5.0 to 6.5. these studies were designed to characterize this phenomenon more comprehensively. liming the soil with either caco(3), ca(oh)(2), mgo, or ... | 1987 | 16347431 |
| influence of phosphate on the growth and nodulation characteristics of rhizobium trifolii. | the growth and nodulating characteristics of rhizobium trifolii 6 and 36 differed under different external phosphate conditions. under growth conditions designed to deplete the internal phosphate content of the rhizobia, strain 6 maintained a generation time of 5 h during the exponential phase over two cycles of growth in phosphate-depleted medium. in contrast, the generation time of strain 36 was extended from 3.5 to 9.8 h over two cycles of phosphate-depleted growth, although the organism even ... | 1987 | 16347432 |
| production of bacterial inoculants by direct fermentation on nutrient-supplemented vermiculite. | when supplemented with a nutrient source and moisture, sterile finely ground vermiculite can be used to directly ferment bacterial cultures to prepare bacterial inoculants. all tested bacterial species, including rhizobium japonicum, r. phaseoli, r. meliloti, r. leguminosarum, bacillus megaterium, and several pseudomonas strains, grew at least 10,000-fold in 1 week at room temperature. the final product was stable and had no special storage or handling requirements. due to the unique properties ... | 1987 | 16347434 |
| conservation of a symbiotic dna region in soybean root nodule bacteria. | bradyrhizobium japonicum usda 3i1b110 contains a dna region in which symbiotic genes and many repeated sequences are closely linked. hybridization analysis revealed that this region was highly conserved in some b. japonicum strains (usda 24, usda 122, usda 123, atcc 10324, 61a24) but not in others (usda 76, 61a76, 61a101). the genomic presence of multiple copies of one of the repeated sequences (rsalpha) appeared to be specifically characteristic for soybean root nodule bacteria, including the f ... | 1987 | 16347446 |
| conserved plasmid hydrogen-uptake (hup)-specific sequences within huprhizobium leguminosarum strains. | thirteen rhizobium leguminosarum strains previously reported as h(2)-uptake hydrogenase positive (hup) or negative (hup) were analyzed for the presence and conservation of dna sequences homologous to cloned bradyrhizobium japonicum hup-specific dna from cosmid phu1 (m. a. cantrell, r. a. haugland, and h. j. evans, proc. natl. acad. sci. usa 80:181-185, 1983). the hup phenotype of these strains was reexamined by determining hydrogenase activity induced in bacteroids from pea nodules. five strains ... | 1987 | 16347471 |
| evidence for genetic exchange and recombination of rhizobium symbiotic plasmids in a soil population. | a soil population of 16 rhizobium leguminosarum bv. trifolii isolates was characterized by using three sym (for symbiotic) plasmid-specific dna hybridization probes: (i) an r. leguminosarum bv. trifolii-specific, repeated-sequence probe; (ii) a nifhdk gene probe, and (iii) a nod gene probe. a predominant sym plasmid family was identified among the isolates. three other unrelated sym plasmid families were also identified. the isolates were also classified either by using a chromosomal dna hybridi ... | 1987 | 16347509 |
| nodule activity and allocation of photosynthate of soybean during recovery from water stress. | nodulated soybean plants (glycine max [l.] merr. cv ransom) in a growth-chamber study were subjected to a leaf water potential (psi w) of -2.0 megapascal during vegetative growth. changes in nonstructural carbohydrate contents of leaves, stems, roots, and nodules, allocation of dry matter among plant parts, in situ specific nodule activity, and in situ canopy apparent photosynthetic rate were measured in stressed and nonstressed plants during a 7-day period following rewatering. leaf and nodul ... | 1987 | 11539766 |
| genes for the catabolism and synthesis of an opine-like compound in rhizobium meliloti are closely linked and on the sym plasmid. | in alfalfa nodules induced by rhizobium meliloti strain l5-30 the compound l-3-o-methyl-scyllo-inosamine (3-o-msi) is synthesized. this compound is also catabolized specifically by this strain. its biological properties are therefore similar to the agrobacterium opines. to answer the question whether opine-like compounds ("rhizopines") play a role in a plant symbiotic interaction, we isolated the genes for the catabolism of 3-o-msi (moc genes) and for the induction of its synthesis in the nodule ... | 1987 | 16593802 |
| rhizobium symbiotic genes required for nodulation of legume and nonlegume hosts. | parasponia, a woody member of the elm family, is the only nonlegume genus whose members are known to form an effective nitrogen-fixing symbiosis with bradyrhizobium or rhizobium species. the bradyrhizobium strain rp501, isolated from parasponia nodules, also nodulates the legumes siratro (macroptilium atropurpureum) and cowpea (vigna unguiculata). to test whether some of the same genes are involved in the early stages of legume and nonlegume nodulation, we generated transposon tn5 insertions in ... | 1987 | 16593814 |
| gene tandem-mediated selection of coliphage lambda-receptive agrobacterium, pseudomonas, and rhizobium strains. | agrobacterium, pseudomonas, and rhizobium spp. have been made receptive to coliphage lambda. to achieve this, recombinant (ptroy) plasmids carrying a constitutive escherichia coli lamb gene encoding the lambda receptor and expressed from an insertion sequence 3 (is3) promoter were introduced into various bacteria. because the wild-type lambda receptor was not expressed in these bacteria, a procedure called the lamb gene tandem protocol was used to select lamb alleles that expressed the lambda re ... | 1987 | 16593836 |
| expression of a complete soybean leghemoglobin gene in root nodules of transgenic lotus corniculatus. | the complete soybean leghemoglobin lbc(3) gene was transferred into the legume lotus corniculatus using an agrobacterium rhizogenes vector system. organ-specific expression of the soybean gene was observed in root nodules formed on regenerated transgenic plants after infection with rhizobium loti. the primary transcript was processed in the same way as in soybean nodules and the resulting mrna was translated into lbc(3) protein. quantitative determination of the lbc(3) protein in nodules of tran ... | 1987 | 16593870 |
| induction of bradyrhizobium japonicum common nod genes by isoflavones isolated from glycine max. | the early events in legume nodulation by rhizobium spp. involve a conserved gene cluster known as the common nod region. a broad-host-range plasmid (pea2-21) containing a bradyrhizobium japonicum noddabc-lacz translational fusion was constructed and used to monitor nod gene expression in response to soybean root extract. two inducing compounds were isolated and identified. analysis using ultraviolet absorption spectra, proton nuclear magnetic resonance, and mass spectrometry showed that the two ... | 1987 | 16593884 |
| extended region of nodulation genes in rhizobium meliloti 1021. i. phenotypes of tn5 insertion mutants. | rhizobium meliloti nod(-) mutant wl131, a derivative of wild-type strain 102f51, was complemented by a clone bank of wild-type r. meliloti 1021 dna, and clone prmjt5 was recovered. transfer of prmjt5 conferred alfalfa nodulation on other rhizobium species, indicating a role in host range determination for prmjt5. mutagenesis of prmjt5 revealed several segments in which transposon insertion causes delay in nodulation, and/or marked reduction of the number of nodules formed on host alfalfa plants. ... | 1987 | 17246399 |
| extended region of nodulation genes in rhizobium meliloti 1021. ii. nucleotide sequence, transcription start sites and protein products. | we have established the dna sequence and analyzed the transcription and translation products of a series of putative nodulation (nod) genes in rhizobium meliloti strain 1021. four loci have been designated nodf, node, nodg and nodh. the correlation of transposon insertion positions with phenotypes and open reading frames was confirmed by sequencing the insertion junctions of the transposons. the protein products of these nod genes were visualized by in vitro expression of cloned dna segments in ... | 1987 | 17246400 |
| absence in monocotyledonous plants of the diffusible plant factors inducing t-dna circularization and vir gene expression in agrobacterium. | t-dna circularization is one of the molecular events specifically induced in agrobacterial cells upon their infection of dicotyledonous plant cells. we developed a seedling co-cultivation procedure to determine whether or not monocotyledonous plants have the ability to induce t-dna circularization and vir gene expression. co-cultivation of agrobacterium tumefaciens with seedlings of dicotyledonous plants showed that the circularization event takes place efficiently. the exudates and extracts of ... | 1987 | 17191337 |
| the ntrc gene of agrobacterium tumefaciens c58 controls glutamine synthetase (gsii) activity, growth on nitrate and chromosomal but not ti-encoded arginine catabolism pathways. | the ntrc locus of agrobacterium tumefaciens c58 has been cloned using the azorhizobium sesbaniae ors571 ntrc gene as a dna hybridization probe. transposon tn5 mutagenesis of the cloned ntrc locus was carried out and one tn5 insertion within the region of highest dna homology with a. sesbaniae ors571 ntrc was used for gene replacement of the wild-type c58 ntrc gene. the a. tumefaciens ntrc::tn5 mutant was found to be unable to grow on nitrate as sole nitrogen (n) source, to lack glutamine synthet ... | 1987 | 17193704 |
| agrobacterium rhizogenes t-dna genes capable of inducing hairy root phenotype. | segments of the tl-dna of the agropine type ri plasmid pri 1855 encompassing single and groups of open-reading frames were cloned in the ti plasmid-derived binary vector system bin 19. leaf disc infections on nicotiana tabacum led to transformed plants, some of which showed typical hairy root phenotypes, such as the wrinkled leaf morphology, excessive and partially non geotropic root systems and the ability of leaf explants to differentiate roots in a hormone-free culture medium. particularly in ... | 1987 | 17193709 |
| a plasmid sequence from rhizobium leguminosarum 300 contains homology to sequences near the octopine tl-dna right border. | the dna sequence from a rhizobium leguminosarum 300 (rl300) plasmid that contains homology to the tc-dna of agrobacterium tumefaciens is described. the rl300 sequence has 78% homology to a 359 bp sequence in the tc-dna of pti15955. the rl300 homology starts approximately 100 bp from the 24 bp border sequence of the tl-dna and ends approximately 3 bp from an is66 homolog in the tc-dna. an unusual feature of the rl300 homology is the presence of 81 bp direct repeats with tc-dna homology, separated ... | 1987 | 17193713 |
| indoleacetic acid production by rhizobium sp. from a leguminous tree, erythrina indica. | rhizobium sp. isolated from the root nodules of erythrina indica lamk., a leguminous tree, produced large amounts of indoleacetic acid (iaa) from tryptophan. l-tryptophan (2 mg/ ml) was preferred to dl-tryptophan for iaa synthesis. attempts were made to optimize the cultural requirements for an accelerated iaa production. an enrichment of the carbon-free incubation medium with maltose (1 %), mnso4 x h2o (5 microg/ml), and triton x-100 (100 ppm) promoted the synthesized iaa content of the medium ... | 1987 | 18425685 |
| biosynthesis and degradation of nodule-specific rhizobium loti compounds in lotus nodules. | two nodule-specific rhizobium loti compounds were identified in lotus tenuis and lotus pedunculatus nodules induced by strain nzp2037. one, a silver nitrate-positive cation called rhizolotine, has been characterized as the riboside of a novel alpha-hydroxyimino acid containing a 1,4,5,6-tetrahydropyrimidine ring (g. j. shaw, r. d. wilson, g. a. lane, l. d. kennedy, d. b. scott, and g. j. gainsford, j. chem. soc. chem. commun., p. 180-181, 1986), and the other, yellow-1, stains yellow with ninhyd ... | 1987 | 3025173 |
| characterization of nonattaching mutants of agrobacterium tumefaciens. | the first step in tumor formation by agrobacterium tumefaciens is the site-specific binding of the bacteria to plant host cells. transposon mutants of the bacteria which fail to attach to carrot suspension culture cells were isolated. these mutants showed no significant attachment to carrot cells with either microscopic or viable cell count assays of bacterial binding. the nonattaching mutants were all avirulent. when revertants of the mutants were obtained by enriching for bacteria which do bin ... | 1987 | 3025176 |
| isolation of competition-defective mutants of rhizobium fredii. | we coupled tn5 mutagenesis with a competition assay to isolate mutants of rhizobium fredii usda 257 that are defective in competition for nodulation of soybeans. two mutants with single tn5 inserts in the chromosome showed reduced competitiveness in vermiculite but were identical to the wild-type strain in symbiotic properties when inoculated alone. recombination of tn5 and flanking genomic regions cloned from the mutants into the parent strain showed that tn5 was responsible for the mutant phen ... | 1987 | 3025184 |
| nitrogen fixation ability of exopolysaccharide synthesis mutants of rhizobium sp. strain ngr234 and rhizobium trifolii is restored by the addition of homologous exopolysaccharides. | several transposon tn5-induced mutants of the broad-host-range rhizobium sp. strain ngr234 produce little or no detectable acidic exopolysaccharide (eps) and are unable to induce nitrogen-fixing nodules on leucaena leucocephala var. peru or siratro plants. the ability of these exo- mutants to induce functioning nodules on leucaena plants was restored by coinoculation with a sym plasmid-cured (nod- exo+) derivative of parent strain ngr234, purified eps from the parent strain, or the oligosacchari ... | 1987 | 3025187 |