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involvement of a plasmid in the hairy root disease of plants caused by agrobacterium rhizogenes. 1979231271
functional analysis of the promoter region of a nodule-enhanced glutamine synthetase gene from phaseolus vulgaris l.the 5'-flanking region of gln-gamma, the nodule-enhanced glutamine synthetase gene from phaseolus vulgaris l., has been analysed for cis-regulatory elements using a series of 5' deletions and hybrid gln-gamma:: camv 35s promoters. the promoters were fused to the uida reporter gene and their activities tested in two heterologous expression systems. in the first system, the chimaeric genes were transferred to lotus corniculatus l. using agrobacterium rhizogenes and their expression was studied in ...19921353692
physical map of the vitopine ti plasmid ptis4.within the agrobacterium vitis group the vitopine strains represent a special subclass. vitopine bacteria carry ti plasmids with little or no homology with the well-characterized t-dnas of agrobacterium tumefaciens or agrobacterium rhizogenes. the 262-kb ti plasmid of the vitopine strain s4 was cloned and mapped. homology studies with the octopine ti plasmid ptiach5, the nopaline ti plasmid ptic58, and the agropine/mannopine ri plasmid prihri identified several regions of homology. the origin of ...19921409971
auxin rapidly down-regulates transcription of the tryptophan decarboxylase gene from catharanthus roseus.the enzyme tryptophan decarboxylase (tdc) (ec 4.1.1.28) converts tryptophan into tryptamine, and thereby channels primary metabolites into indole alkaloid biosynthesis. the production of these secondary metabolites in suspension cells of catharanthus roseus depends on medium composition. of the possible variables, we investigated the effect of hormones on the expression of the tdc gene in cell cultures. omission of naa from the growth medium resulted in accumulation of tdc mrna. the addition of ...19921600147
molecular basis for novel root phenotypes induced by agrobacterium rhizogenes a4 on cucumber.we have used the wild-type agrobacterium rhizogenes strain a4 to induce roots on cucumber stem explants. cultures of transformed roots obtained that were capable of hormone-autonomous growth could be grouped in three phenotypic classes. of particular interest were extremely thick roots of a type not previously described. characterization of the transferred dna and of the expression of the corresponding genes allowed us to determine that the genes rolabc of the tl region of the ri plasmid are suf ...19921623191
transgenic medicinal plants: agrobacterium-mediated foreign gene transfer and production of secondary metabolites.agrobacterium-ti/ri plasmids are natural gene vectors, by which a number of attempts have been made in genetic engineering of secondary metabolism in pharmaceutically important plants in the last few years. opines are biosynthesized by transformed crown galls and hairy roots integrated with t-dnas of ti/ri plasmids. these opines are classified into five families according to their structures and biogenesis. the production of opines is a natural example of genetic engineering of the biosynthetic ...19921624938
direct regeneration of transformed shoots in brassica napus from hypocotyl infections with agrobacterium rhizogenes.genetically transformed root clones of rapeseed (brassica napus) were obtained after in vitro infection of excised hypocotyl segments with a wild type strain of agrobacterium rhizogenes and two strains of a. rhizogenes harbouring kanamycin resistance. the ability of hairy root formation was affected by light and was highly dependent on the location of the infection site at the hypocotyl. inoculation of decapitated hypocotyls with an intact root system gave rise to direct shoot formation from the ...19911651126
codon usage and g + c content in bradyrhizobium japonicum genes are not uniform.to date, the sequences of 45 bradyrhizobium japonicum genes are known. this provides sufficient information to determine their codon usage and g + c content. surprisingly, b. japonicum nodulation and nifa-regulated genes were found to have a less biased codon usage and a lower g + c content than genes not belonging to these two groups. thus, the coding regions of nodulation genes and nifa-regulated genes could hardly be identified in codon preference plots whereas this was not difficult with oth ...19911793334
repetitive sequences with homology to bradyrhizobium japonicum dna and the t-dna of agrobacterium rhizogenes are closely linked to nodabc of rhizobium fredii usda257.we have detected strong homology between a 9.2-kb ecori restriction fragment from rhizobium fredii usda257 that contains nodabc and eight additional ecori fragments in dna digests from this organism. a series of repetitive sequences responsible for this hybridization lies within a 0.95-kb hindiii/sali subfragment about 1-kb upstream of noda. this subfragment also hybridizes to multiple restriction fragments from nine other strains of r. fredii, but only one is common to all strains. the 0.95-kb ...19911799702
the influence of plant growth regulators on callus induction in pumpkin (cucurbita pepo l.) hairy roots.following in vitro infection with agrobacterium rhizogenes wild strain (mannopine, 8196) and two a. tumefaciens transconjugant strains (c58c1 para4abc and c58c1 para4b) transformed (hairy) roots were induced in pumpkin (c. pepo l.) cotyledons. the presence of pri t-dna in pumpkin long-term hairy root cultures was determined by southern hybridization. the influence of plant growth regulators on callus induction in root explants from hairy root lines, which differed mutually in morphology and grow ...19911814408
organization of the agropine synthesis region of the t-dna of the ri plasmid from agrobacterium rhizogenes.the agropine/mannopine synthesis region of the tr region of the ri plasmid of agrobacterium rhizogenes strain a4 was localized on the basis of sequence similarity with probes from ti plasmids of agrobacterium tumefaciens and analysis of transposon insertions. the nucleotide sequence of the right part of the tr-dna of pria4, encompassing the three genes involved in mannityl-opine synthesis, was determined and compared to the sequence of the corresponding region of the octopine-type ti plasmid pti ...19911852015
35s-beta-glucuronidase gene blocks biological effects of cotransferred iaa genes.the iaam and iaah genes of agrobacterium tumefaciens and agrobacterium rhizogenes play an important role in crown gall and hairy root disease. the iaam gene codes for tryptophan monooxygenase which converts tryptophan into indole-3-acetamide (iam). iam is converted into the auxin indole-3-acetic acid (iaa) by indoleacetamide hydrolase, encoded by the iaah gene. in functional studies on the activity of the iaa genes of the tb region of the a. tumefaciens biotype iii strain tm4, the frequently use ...19911859868
cytosolic localization in transgenic plants of the rolc peptide from agrobacterium rhizogenes.the rolc gene of agrobacterium rhizogenes codes for a peptide with an apparent molecular weight of approximately 20 kda. immunolocalization of the rolc peptide, in leaves of transgenic plants which are genetic mosaics for the expression of the rolc gene, is restricted to the phenotypically altered sectors. subcellular fractionation of homogenates from 35s-rolc transgenic leaves shows the cytosolic localization of the rolc peptide.19911884008
different promoter regions control level and tissue specificity of expression of agrobacterium rhizogenes rolb gene in plants.expression of the rolb gene of a. rhizogenes t-dna triggers root differentiation in transformed plant cells. in order to study the regulation of this morphogenetic gene, the gus reporter gene was placed under the control of several deleted fragments of the rolb 5' non-coding region: carrot disc transformations and the analysis of transgenic tobacco plants containing these constructions identified the presence of distinct regulatory domains in the rolb promoter. two regions (located from position ...19911893111
agrobacterium rhizogenes pri8196 t-dna: mapping and dna sequence of functions involved in mannopine synthesis and hairy root differentiation.this paper presents the map and dna sequence analysis of pri8196 transferred dna (t-dna) genes encoding root-inducing and mannopine synthesis functions. a canonical 24-base-pair border repeat as well as two "pseudoborders" are present at the functional right t-dna border. to the left of this border are homologs of the mas1' and mas2' genes of tr pria4. next to these are five open reading frames (orfs) homologous to orfs 10-14 of tl of pria4. orfs 10-12 (rola, rolb, and rolc) are less related to ...19911909028
expression of a brassica napus extensin gene in the vascular system of transgenic tobacco and rape plants.the organs and tissues where the brassica napus exta extensin gene is expressed have been identified. the exta gene with 3.75 kb of 5' flanking sequence was transferred to tobacco via disarmed agrobacterium tumefaciens vectors and transgenic plants regenerated. the gene was found to be inactive in transgenic tobacco leaf, but was active as measured by rna transcript assays in both stem and root tissues. to determine the cell-specific expression pattern of the exta gene, a promoter-reporter gene ...19911912494
the plant oncogene rolc is responsible for the release of cytokinins from glucoside conjugates.the rolc gene of agrobacterium rhizogenes, which drastically affects growth and development of transgenic plants, codes for a cytokinin-beta-glucosidase. indeed, rolc protein expressed in escherichia coli as a fusion protein hydrolyses cytokinin glucosides, thus liberating free cytokinins. furthermore, beta-glucosidase activity present in e. coli extracts expressing the rolc protein was inhibited by affinity-purified antibodies specific for the rolc protein. finally, rolc proteins expressed in t ...19911915268
the protein encoded by the rolb plant oncogene hydrolyses indole glucosides.the rolb gene of agrobacterium rhizogenes, whose expression stimulates the formation of roots by transformed plant tissues and other growth alterations in transgenic plants, codes for a beta-glucosidase able to hydrolyse indole-beta-glucosides. indeed, we show that extracts of bacteria and/or plant tissue expressing the rolb protein hydrolyse indoxyl-beta-glucoside (plant indican). because of the structural similarity between indoxyl-beta-glucoside and indole-3-acetyl-beta-glucoside (iaa-beta-gl ...19911915286
agrobacterium rhizogenes lacz-rolc gene expression in escherichia coli: detection of the product in transgenic plants using rolc-specific antibodies.the rolc sequence of the agrobacterium rhizogenes ri plasmid was fused in-frame to the 3' end of the lacz gene in plasmid pex3. the fusion protein rolc-beta-galactosidase was accumulated as insoluble inclusion bodies in escherichia coli. antibodies were raised in rabbits against the fusion protein. after affinity purification, rolc-specific antibodies were found to react with a 22-kda polypeptide prepared from roots of transgenic tobacco plants possessing a rolc gene. the result of differential ...19911916283
the tr-dna region carrying the auxin synthesis genes of the agrobacterium rhizogenes agropine-type plasmid pria4: nucleotide sequence analysis and introduction into tobacco plants.we have determined the nucleotide sequence of a 6-kilobase fragment of the agrobacterium rhizogenes plasmid pria4 tr-region that carries genes (aux1 and aux2) responsible for auxin biosynthesis in transformed plant cells. sequence analysis revealed two open reading frames corresponding to proteins of 749 amino acids for the aux1 gene and 466 amino acids for the aux2 gene. we observed significant similarity between the amino acid sequences deduced from the pria4 aux genes and those of the auxin b ...19911932811
frequent spontaneous deletions of ri t-dna in agrobacterium rhizogenes transformed potato roots and regenerated plants.the presence of t-dna was examined by southern blot analysis in 16 regenerated shoot lines derived from 6 agrobacterium rhizogenes-transformed root clones of solanum tuberosum l. cv. bintje. tr-dna, present in regenerated shoot lines from 3 out of 6 root clones was correlated with the presence of opines. one root clone produced opines up to 2.5 years of subculture. however, plant regeneration from and prolonged subculturing of this root clone resulted in loss of opine synthesis, caused by deleti ...19901966386
inhibition of the expression of the gene for granule-bound starch synthase in potato by antisense constructs.granule-bound starch synthase [gbss; ec 24.1.21] determines the presence of amylose in reserve starches. potato plants were transformed to produce antisense rna from a gene construct containing a full-length granule-bound starch synthase cdna in reverse orientation, fused between the cauliflower mosaic virus 35s promoter and the nopaline synthase terminator. the construct was integrated into the potato genome by agrobacterium rhizogenes-mediated transformation. inhibition of gbss activity in pot ...19912005870
identification of a putative rol b gene on the tr-dna of the agrobacterium rhizogenes a4 ri plasmid. 19902102840
the ptic58 tzs gene promotes high-efficiency root induction by agropine strain 1855 of agrobacterium rhizogenes.root induction on flax (linum usitatissimum l.) cotyledon explants by agrobacterium rhizogenes strain 1855 is markedly increased by co-inoculation with disarmed a. tumefaciens strain lba 4404 containing a plasmid carrying the tzs gene of ptic58. most of the roots (estimated to be more than 90%) were transformed. this effect is most likely due to the secretion of trans-zeatin by a. tumefaciens stimulating the division of plant cells making them more receptive to transformation by a. rhizogenes, a ...19902102856
the non-conserved region of cucumopine-type agrobacterium rhizogenes t-dna is responsible for hairy root induction.the t-dna regions of three strains of ri plasmids 1855, 8196, 2659 (agropine, mannopine and cucumopine type respectively) share two highly conserved regions flanking a non-homologous central part. we have cloned segments of the cucumopine ri plasmid 2659 t-dna in the binary vector system bin 19 and infected carrot discs with recombinant agrobacterium strains. we show here that the central non-conserved region is crucial in hairy root induction as it is sufficient to induce rooting on the apical ...19902102883
plant regeneration from ri t-dna transformed roots of cabbage.ri t-dna transformed roots were induced out on hypocotyl segments of cabbage infected with agrobacterium rhizogenes. after cultured for four months on solid ms medium without hormones, some parts of a few of transformed roots were dedifferentiated into callus clumps, and then redifferentiated into shoot buds. on solid ms medium supplemented with kinetin, shoot buds were differentiated directly from transformed roots without callus formation. among several concentrations of kinetin, 14 microm gav ...19902104201
use of mutants and transformed plants to study the action of auxins.we describe here the results of a comparison of the properties of several plant genotypes differing in their reaction to auxins. the hormonal response used to compare the genotypes is the auxin-induced variation of the transplasmalemma electrical potential difference (delta em) exhibited by protoplasts isolated from leaves or root tips. using this membrane response, we have shown that large variations in the sensitivity to auxins can be induced either by mutagenesis in tobacco or by transformati ...19902130519
expression of agrobacterium rhizogenes rolb gene fusions in escherichia coli: production of antibodies against the rolb protein.expression of the rolb gene of agrobacterium rhizogenes tl-dna is sufficient to trigger root differentiation in transformed plant cells. to investigate the role of rolb in differentiation, a large portion of rolb, comprising about 90% of its c-terminal coding sequence, was cloned into vectors pex34 and pea305 in frame with the truncated n termini of the pl-ms2 phage dna polymerase and, respectively, the ptac-c its phage lambda repressor gene. hybrid proteins were expressed from both fusions and ...19902185136
characterization of the vira gene of the agropine-type plasmid pria4 of agrobacterium rhizogenes.we sequenced a 4.2-kb dna region encompassing the vir a locus of the hairy-root-inducing plasmid pria4, and compared its sequence with the published vir a region sequences of four tumor-inducing plasmids. an open reading frame capable of coding for 829 amino acids was identified for vir a. deletion mutants of vir a constructed by fusing to lacz, but not the wild-type game itself, were efficiently expressed in escherichia coli when they were put downstream front the lac promoter. these fused gene ...19902226811
agrobacterium rhizogenes mutants that fail to bind to plant cells.transposon insertion mutants of agrobacterium rhizogenes were screened to obtain mutant bacteria that failed to bind to carrot suspension culture cells. a light microscope binding assay was used. the bacterial isolates that were reduced in binding to carrot cells were all avirulent on bryophyllum diagremontiana leaves and on carrot root disks. the mutants did not appear to be altered in cellulose production. the composition of the medium affected the ability of the parent and mutant bacteria to ...19902228955
auxin regulates the promoter of the root-inducing rolb gene of agrobacterium rhizogenes in transgenic tobacco.the regulation in tobacco of the rolb and rolc promoters of agrobacterium rhizogenes pri 1855 tl-dna was studied by using the beta-glucuronidase (gus) reporter system in transgenic plants. a 20- to 100-fold increase of gus activity was selectively induced by auxin in rolb-gus transformed mesophyll protoplasts, whereas this auxin-dependent increase was only 5-fold in rolc-gus protoplasts. moreover, both gene fusions exhibited similar tissue-specific expression in aerial parts but different patter ...19902259343
structure and expression of ri t-dna from agrobacterium rhizogenes in nicotiana tabacum. organ and phenotypic specificity.the incorporation of transferred dna (t-dna) from the ri plasmid of agrobacterium rhizogenes into the chromosomal dna of higher plants is correlated with the appearance of a complex phenotype. the transformed genotype and phenotype undergo mendelian inheritance. through studies of ri t-dna content and transcription in nicotiana tabacum, we have delineated a particular part of this foreign dna as the likely source of the transformed phenotype. one inducible/repressible aspect of the transformed p ...19852419571
use of roots transformed by agrobacterium rhizogenes in rhizosphere research: applications in studies of cadmium assimilation from sewage sludges.the use of roots transformed by agrobacterium rhizogenes in models for the rhizosphere is discussed. a list of species for which transformed root cultures have been obtained is provided and the example of studies of cadmium assimilation from sewage sludges is given to illustrate how transformed root cultures can be used in physiological tests under non-sterile conditions.19892491656
promoters of the rola, b, and c genes of agrobacterium rhizogenesare differentially regulated in transgenic plants.chimeric genes containing the beta-glucuronidase reporter gene under the control of the rola, b, and c promoters of agrobacterium rhizogenes are expressed in a regulated manner in transgenic plants. the intergenic region separating the rolb and c genes represents a bidirectional promoter. this bidirectional promoter regulates transcription for both genes in a similar fashion in aerial organs of the plants, but in a distinct way in roots. moreover, both rolb and c promoter activities differ from ...19892535517
cell-autonomous behavior of the rolc gene of agrobacterium rhizogenes during leaf development: a visual assay for transposon excision in transgenic plants.we describe a genetic switch based on the ac transposable element of maize and the rolc gene of agrobacterium rhizogenes, a dominant gene, which has pleiotropic effects on plant growth and morphology. moreover, rolc gene expression under the control of the 35s cauliflower mosaic virus promoter decreases chlorophyll content in transgenic tobacco plants. chlorophyll is a visible cell-autonomous marker, and it is shown here that the reduction in chlorophyll content caused by the rolc gene product a ...19892562512
induction and growth properties of carrot roots with different complements of agrobacterium rhizogenes t-dna.single and multiple infections of carrot discs were carried out with agrobacterium strains harbouring different segments of pri1855 tl-dna cloned in the binary vector bin 19 and with a strain carrying the tr-dna from the same ri plasmid. roots induced by the various co-inoculations were cultured and their growth patterns were followed. abundant roots could be induced by tl-dna rol genes a, b and c as a single insert (rola + b + c) and by rolb alone provided an extended segment beyond its 5' non- ...19892562759
nucleotide sequence of the tzs gene from agrobacterium rhizogenes strain a4. 19892685753
physical map of the t-dna region of agrobacterium rhizogenes strain ncppb2659.the t-dna region of the plasmid responsible for hairy root in the agrobacterium rhizogenes strain ncppb2659 is identified and characterized by its physical map.19872827205
studies on the introduction and mobility of the maize activator element in arabidopsis thaliana and daucus carota.we have co-transformed carrot (daucus carota) and arabidopsis thaliana with an agrobacterium tumefaciens non-tumorigenic t-dna carrying the maize transposable element activator (ac) and an agrobacterium rhizogenes ri t-dna. we present evidence that the ac element transposes in transformed root or root-derived callus cultures of both species. we show that fertile plants can be regenerated from transformed, root-derived callus cultures of arabidopsis, demonstrating the utility of the ri plasmid fo ...19872832144
mini-mulac transposons with broad-host-range origins of conjugal transfer and replication designed for gene regulation studies in rhizobiaceae.novel mini-mu derivatives were constructed, carrying a truncated laczya operon fused to the terminal 117 bp of the mu s-end, for the isolation of translational lac fusions by mini-mu-mediated insertion mutagenesis. different selectable markers (chloramphenicol resistance; gentamycin resistance) were introduced to allow selection for mini-mu insertions in different replicons and bacterial strains. a mini-mulac derivative carrying the site for conjugal transfer of plasmid rp4 (orit) and the origin ...19882838383
homology mapping of t-dna regions on three agrobacterium rhizogenes ri plasmids by electron microscope heteroduplex studies.recombinant plasmids carrying segments of the agrobacterium rhizogenes t-dna regions of the three ri plasmids 1855 (tl-dna only), 8196, and 2659 were used for establishing homology maps by electron microscope examination of heteroduplexes. plasmid dna was linearized by digestion with suitable restriction endonucleases in order to generate large t-dna segments. heteroduplexes were prepared in 50% formamide and spread under standard conditions. measurements of double and single strands allowed the ...19882843937
map location on agrobacterium root-inducing plasmids of homologies with the virulence region of tumor-inducing plasmids.southern-type hybridizations were carried out in order to identify sequence homologies with the pti vir loci, on an agropine-type plasmid (prihri) and a mannopine-type plasmid (pri8196) of agrobacterium rhizogenes. the localization of the sequences hybridizing with subcloned fragments containing vir a, b, g, c, and d from ptiach5 indicated a similar linear organization of the pti vir loci and their homologies on prihri and pri8196, though no homology was detected on both pri with a 1.1-kb intern ...19882852815
lacz gene fusions and insertion mutagenesis in the tl-region of agrobacterium rhizogenes ri plasmid.agrobacterium rhizogenes induces root formation and inserts a fragment of its plasmid into the genome of infected plants. a part of the transferred region (tl-region) of the ri plasmid of a. rhizogenes strain a4 was cloned in pbr322. insertions of the escherichia coli lacz coding region into the hybrid plasmids were made in vivo using mini-mu-duction. two mini-mus were used, one with the mu a and b transposase genes (mudii1681) and the other without (mudii1734). two inserts which result in e. co ...19852994128
nucleotide sequence analysis of tl-dna of agrobacterium rhizogenes agropine type plasmid. identification of open reading frames.we have determined the nucleotide sequence of the ri tl-dna region from an agrobacterium rhizogenes agropine-type plasmid using subcloned regions from the essentially identical ri tl-dnas from strains a4 and hri. this sequenced region of 21,126 base pairs (bp) contains the complete tl-dna region of the ri plasmid as determined by analysis of tl-dna borders in the genome of infected, clonal, convolvulus arvensis plants. the left and right borders of the tl-dna are flanked by 25-bp sequences which ...19863001043
multiple mutations in the transferred regions of the agrobacterium rhizogenes root-inducing plasmids.agrobacterium rhizogenes induces root formation at the site of inoculation in plants and inserts fragments of its ri plasmid into the plant nuclear dna. the transferred region (t-dna) of the ri plasmid of the a. rhizogenes strain a4 is made of two fragments, namely tl and tr; the latter harbors a sequence homology with the tms loci (responsible for auxin synthesis) of a. tumefaciens. on daucus carota slices, single insertion mutations on the tl region of a. rhizogenes do not confer a mutant phen ...19863012616
construction and uses of a new transposable element whose insertion is able to produce gene fusions with the neomycin-phosphotransferase-coding region of tn903.we describe the construction of a transposable element derived from the mu phage that upon insertion is able to create a gene fusion between the region of tn903 coding for neomycin phosphotransferase (npt i), which confers resistance to aminoglycosides including kanamycin (kmr), neomycin and g418, and the control elements of the gene where the insertion occurs. a chloramphenicol (cm) transacetylase gene (cat) that confers resistance to cm is present in the transposon so that transposition events ...19863015731
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 ...19863018814
expression vectors based on the agrobacterium rhizogenes ri plasmid transformation system.this article describes several new expression vectors that capitalize on the ability of agrobacterium rhizogenes to transfer dna from its ri plasmid to the plant nuclear genome. the intermediate vectors described include an expression cassette based on one of the three following promoters: the nopaline synthase promoter, or the cauliflower mosaic virus (camv) promoters responsible for transcription of either the 19s or 35s camv rna. the termination and polyadenylation signals are either from the ...19873111548
agrobacterium rhizogenes as a vector for transforming higher plants.agrobacterium rhizogenes is a natural vector for genetically transforming higher plants. a protocol is given for using this system to insert foreign genes into host plants. improvements currently being developed in several laboratories are also discussed.19873153165
rola locus of the ri plasmid directs developmental abnormalities in transgenic tobacco plants.plants containing the left t-dna (tl) of agrobacterium rhizogenes show a variety of developmental abnormalities that include severely wrinkled leaves, loss of apical dominance, reduced geotropism of roots, reduced internode distances, and floral hyperstyly. the tl-dna also affects the morphology of tumor tissue at the site of inoculation on kalanchoe diagremontiana leaves. single mutations at four loci of the tl-dna (rola, rolb, rolc, and rold) are known to affect tumor morphology on k. diagremo ...19883166443
organization and characterization of the vircd genes from agrobacterium rhizogenes.we have precisely localized virulent (vir) genes of the hairy root-inducing plasmid pria4b on the basis of sequence similarity with the tumor-inducing plasmid ptia6nc, and shown that the overall organizations of vir genes in both plasmids are fairly analogous, although sizes and spacer lengths in some genes differ from each other. among the vir genes thus mapped, the virc and vird loci were characterized in detail. transposon insertions in vird led to loss of tumorigenicity on kalanchoe stems an ...19883185501
homology studies demonstrate colinear organization of the transferred regions of plasmids pri 1855 and pri 8196 from agrobacterium rhizogenes.agrobacterium rhizogenes, a pathogenic bacterium determining for hairy-root tumors in plants, acts by insertion of a fragment (t-dna) of its ri plasmid into the plant nuclear dna. two a. rhizogenes strains, pri 1855 and pri 8196, responsible for similar disease symptoms, differ when compared at the structural level. however, some morphogenetic loci previously identified by insertion mutagenesis in either one of the two t-dnas seem physiologically equivalent. the possibility that these morphogene ...19873615659
a new vector derived from agrobacterium rhizogenes plasmids: a micro-ri plasmid and its use to construct a mini-ri plasmid.a new binary vector system has been constructed, based on agropine-type root-inducing plasmid (pri) left transferred-region border sequences cloned in a plasmid containing the replication origin of another a. rhizogenes plasmid (para4a). this micro-pri has been used to introduce a chimeric kanamycin resistance gene into tobacco plants, vir functions being provided by either octopine or nopaline tumor-inducing plasmids deleted of their own transferred regions. in addition, we show that cloning of ...19873623102
cytokinin production by agrobacterium and pseudomonas spp.the production of cytokinins by plant-associated bacteria was examined by radioimmunoassay. strains producing trans-zeatin were identified in the genera agrobacterium and pseudomonas. agrobacterium tumefaciens strains containing nopaline tumor-inducing plasmids, a. tumefaciens lippia isolates, and agrobacterium rhizogenes strains produced trans-zeatin in culture at 0.5 to 44 micrograms/liter. pseudomonas solanacearum and pseudomonas syringae pv. savastanoi produced trans-zeatin at levels of up t ...19873624204
enzymes of the beta-ketoadipate pathway are inducible in rhizobium and agrobacterium spp. and constitutive in bradyrhizobium spp.protocatechuate is a universal growth substrate for members of the family rhizobiaceae, and these bacteria utilize the aromatic compound via the beta-ketoadipate pathway. this report describes transcriptional controls exercised by different subgroups of the rhizobiaceae over five enzymes that catalyze consecutive reactions in the pathway: protocatechuate oxygenase (ec 1.13.11.3), beta-carboxy-cis,cis-muconate lactonizing enzyme (ec 5.5.1.2), gamma-carboxymuconolactone decarboxylase (ec 4.1.1.44) ...19863941043
localization of agropine-synthesizing functions in the tr region of the root-inducing plasmid of agrobacterium rhizogenes 1855.the region of the ri plasmid pri 1855 that encodes agropine synthesis has been identified through its sequence homology with the equivalent genes of the octopine ti plasmid pti ach5. interestingly the agropine genes lie outside the so-far identified t-dna of pri 1855, and are separated from this latter by a long sequence of non integrated plasmid dna. the presence of this additional t-dna (tright dna) in hairy roots was demonstrated by southern blot analysis and by the presence of specific trans ...19853991808
molecular and genetic analysis of the transferred dna regions of the root-inducing plasmid of agrobacterium rhizogenes.the t-dna regions of the root-inducing (ri) plasmid pria4b of agrobacterium rhizogenes were characterized. two regions, designated tl-dna and tr-dna, were found to be integrated and stably maintained in the plant genome. the tl-dna spanned a 15- to 20-kilobase region of pria4b and was separated from the tr-dna region by at least 15 kilobases of nonintegrated plasmid dna. the tr-dna region also spanned a 15- to 20-kilobase region of pria4b and included a region of homology to the tms morphogenic ...19854044524
heterologous hybridization of bacterial dna to the endoglucanases a and b structural genes cela and celb of clostridium thermocellum.dna from various cellulolytic and non-cellulolytic bacteria was found to hybridize to clostridium thermocellum ncib10682 dna fragments carrying the structural genes cela and celb which code for endoglucanases a and b. homology to cela was detected in agrobacterium rhizogenes, azospirillum brasilense, bacillus subtilis, cellulomonas sp., clostridium stercorarium, erwinia chrysanthemi, pseudomonas solanacearum and streptomyces griseus. homology to celb was detected only in b. subtilis, c. stercora ...19854083831
deoxyribonucleic acid homology and taxonomy of agrobacterium, rhizobium, and chromobacterium.hybridization experiments were carried out between high molecular weight, denatured, agar-embedded deoxyribonucleic acid (dna) and homologous, nonembedded, sheared, denatured (14)c-labeled dna from a strain of agrobacterium tumefaciens and rhizobium leguminosarum (the reference strains) in the presence of sheared, nonembedded, nonlabeled dna (competing dna) from the same or different nomen-species of agrobacterium, rhizobium, chromobacterium, and several other organisms. percentage of dna homolo ...19674961629
induction of adventitious roots by culture filtrates of the hairy root bacterium, agrobacterium rhizogenes. 19715156939
the t-dna of agrobacterium rhizogenes is transmitted through meiosis to the progeny of hairy root plants.plants regenerated from tobacco hairy root callus cultures were fertilized by self-pollination, and healthy, morphologically normal r1 offspring were obtained. three of these r1 seedlings were analyzed for the presence of t-dna and synthesis of the t-dna-specific compound agropine. all three r1 plants analyzed contained the same full-length t-dna as the parental regenerant, while only two showed agropine synthesis.19846090564
restriction map of an agropine-type ri plasmid and its homologies with ti plasmids.the ri plasmid of an agropine-type agrobacterium rhizogenes, strain hri, was cloned in a cosmid and mapped with the restriction endonucleases bamhi, ecori, kpni, smai, and xbai. this plasmid is almost identical to pri1855 and pria4b. a study by southern hybridizations of the homologies with octopine ptib6806 and nopaline ptic58 makes it possible to propose the localization of certain functions on this plasmid, such as virulence, agropine catabolism, agropine synthesis, and the origin of replicat ...19846095353
hairy root: plasmid encodes virulence traits in agrobacterium rhizogenes.agrobacterium rhizogenes strain 15834, which incites hairy root disease in plants, harbors three large plasmids: par15834a (107 x 10(6) daltons), par15834b (154 x 10(6) daltons), and par15834c (258 x 10(6) daltons). kanamycin-resistant transconjugants were selected in a cross of kanamycin-resistant derivate of strain 15834 and an avirulent recipient. the transconjugants belonging to one class were virulent and contained all three donor plasmids. these transconjugants also acquired sensitivity to ...19806245060
fingerprinting and sequence homology of plasmids from different virulent strains of agrobacterium rhizogenes. 19816264521
method for the transfer of large cryptic, non-self-transmissible plasmids: ex planta transfer of the virulence plasmid of agrobacterium rhizogenes. 19826292973
restriction endonuclease mapping of the root-inducing plasmid of agrobacterium rhizogenes 1855.the root-inducing plasmid of the agropine type agrobacterium rhizogenes 1855 was mapped by means of the restriction endonuclease ecori. the circular arrangement of the more than 60 fragments generated by this enzyme was established by electrophoretic analysis of pbr322 clones harboring overlapping segments of pri1855 derived by partial digestion with ecori. a large region of the plasmid comprising the t-dna was mapped with two additional enzymes, bamhi and hindiii, by means of southern blot hybr ...19836314408
physical map of the agrobacterium rhizogenes strain 8196 virulence plasmid.virulence of agrobacterium rhizogenes, agent of hairy root disease, is conferred by large plasmids called ri (root-inducing) plasmids. we have determined the bamhi fragment map of pri8196, mw 143 mda, principally by analysis of recombinant plasmids containing overlapping bamhi partial-digest fragments. clones containing solitary bamhi inserts of remaining unmapped fragments were used to probe a series of southern-blotted, pri8196-derived ecori, psti, hindiii, sali, or smai digests. continguous h ...19846324259
hairy-root-inducing plasmid: physical map and homology to tumor-inducing plasmids.a physical map was constructed for the 250-kilobase plasmid pria4b, which confers the virulence properties of a strain of agrobacterium rhizogenes for hairy root disease in plants. the complete hindiii and kpni restriction map was determined from a collection of overlapping hindiii partial digest clones. homologous regions with two well-characterized plasmids that confer virulence for crown gall disease, plasmids ptia6 and ptit37, were mapped on pria4b. as much as 160 kilobases of pria4b had det ...19846690423
transformation of several species of higher plants by agrobacterium rhizogenes: sexual transmission of the transformed genotype and phenotype.the t-dna of the ri plasmid from agrobacterium rhizogenes is compatible with the regeneration of whole plants from genetically transformed roots and is transmitted through meiosis to the progeny of genetically transformed plants in carrot, tobacco, and morning glory (convolvulus arvensis). the presence of ri t-dna is correlated with a phenotype that in some respects is invariable from species to species and in other respects varies as a function of species, organ clone within species, or individ ...19846744417
structure of t-dna in roots transformed by agrobacterium rhizogenes.dna isolated from hairy roots incited on daucus carota by agrobacterium strains harboring the ri plasmid was probed with ri plasmid fragments to identify plasmid sequences transferred and integrated into the plant genome. one hairy root line was incited by an a. rhizogenes natural isolate strain harboring two large plasmids in addition to the ri plasmid. dna from hairy roots incited by this strain contained a total of five nonidentical copies of t-dna which together comprised a t-dna complement ...19836875427
regions of homology between tumorigenic plasmids from agrobacterium rhizogenes and agrobacterium tumefaciens. 19827089090
relationship of plasmids responsible for hairy root and crown gall tumorigenicity.three strains of agrobacterium rhizogenes were examined for plasmids. strains 15834 and a4 contained essentially identical large plasmids, par15834c and para4c, respectively (approximately 260 x 10(6) daltons). these plasmids can dissociate to two smaller plasmid species. strain tr105 contained only a single plasmid, which was homologous with the dissociation product of par15834c, par15834b. plasmid par15834c shared little overall sequence homology with other ti plasmids. one region of conserved ...19807430069
tumor formation and rhizogenicity of agrobacterium rhizogenes carrying ti plasmids.octopine ti plasmids were introduced into different agrobacterium rhizogenes strains. transconjugants became able to utilize octopine and to induce aberrant tumors, the surface of which was all covered wioth roots of different size and morphology. the plasmids endogenous in a. rhizogenes were shown to be compatible with incrh-1 ti plasmids.19807439687
universal pcr primers for detection of phytopathogenic agrobacterium strains.two pcr primer pairs, based on the vird2 and ipt genes, detected a wide variety of pathogenic agrobacterium strains. the endonuclease domain of vird2 protein, which cleaves transferred dna (t-dna) border sequences, is highly conserved; primer oligonucleotides specific for the endonuclease portion of vird2 detected all pathogenic strains of agrobacterium tested. pcr primers corresponding to conserved sequences in ipt, the t-dna-borne cytokinin synthesis gene, detected only agrobacterium tumefacie ...19957487020
horizontal gene transfer: regulated expression of a tobacco homologue of the agrobacterium rhizogenes rolc gene.a tobacco homologue (trolc) of the rolc gene of the agrobacterium rhizogenes ri-plasmid was cloned and sequenced from nicotiana tabacum l. cv. havana 425. the coding region of trolc is similar in sequence (69-87% for dna and 54-89% for the deduced amino acid sequence) to rolc genes of the agropine, mannopine, and mikimopine strains of ri-plasmids and the n. glauca rolc homologue. southern analyses showed that trolc is encoded by a small gene family derived from the tomentosiformis ancestor of to ...19957500950
splicing of the rola transcript of agrobacterium rhizogenes in arabidopsis.the rola gene encoded on the ri plasmid a4 of agrobacterium rhizogenes is one of the transferred (tl-dna) genes involved in the pathogenesis of hairy-root disease in plants. the function of the 100-amino acid protein product of rola is unknown, although its expression causes physiological and developmental alterations in transgenic plants. the rola gene of a. rhizogenes contains an intron in its untranslated leader region that has features typical of plant pre-messenger rna introns. transcriptio ...19947528444
taxonomic study of bacteria isolated from plants: proposal of sphingomonas rosa sp. nov., sphingomonas pruni sp. nov., sphingomonas asaccharolytica sp. nov., and sphingomonas mali sp. nov.the taxonomic positions of 10 strains of 3-ketolactose-forming bacteria which were isolated from the roots of plants (rosa sp., psychotria nairobiensis, ardisia crispa, prunus persica, and apple trees) were investigated. the dna base compositions of these strains ranged from 64.0 to 65.7 mol%, the isoprenoid quinone of each strain was ubiquinone 10, 3-hydroxy fatty acids were lacking in the cellular fatty acids of these organisms, and all of the strains contained a sphingolipid with the long-cha ...19957537068
a 200 bp region of the pea enod12 promoter is sufficient for nodule-specific and nod factor induced expression.enod12 is one of the first nodulin genes expressed upon inoculation with rhizobium and also purified nod factors are able to induce enod12 expression. the enod12 gene family in pea (pisum sativum) has two members. a cdna clone representing psenod12a [26] and a psenod12b genomic clone [7] have been previously described. the isolation and characterization of a psenod12a genomic clone is presented in this paper. by using a vicia hirsuta-agrobacterium rhizogenes transformation system it is shown tha ...19957548827
identification of rhizobium-specific intergenic mosaic elements within an essential two-component regulatory system of rhizobium species.analysis of the dna regions upstream of the phosphoenolpyruvate carboxykinase gene (pcka) in rhizobium meliloti and rhizobium sp. strain ngr234 identified an open reading frame which was highly homologous to the agrobacterium tumefaciens chromosomal virulence gene product chvi. a second gene product, 500 bp downstream of the chvi-like gene in r. meliloti, was homologous to the a. tumefaciens chvg protein. the homology between the r. meliloti and a. tumefaciens genes was confirmed, because the r. ...19957559334
evaluation in tobacco of the organ specificity and strength of the rold promoter, domain a of the 35s promoter and the 35s2 promoter.in order to study the expression in plants of the rold promoter of agrobacterium rhizogenes, we have constructed chimaeric genes placing the coding region of the gusa (uida) marker gene under control of two rold promoter fragments of different length. similar results were obtained with both genes. expression studies were carried out in transformed r1 progeny plants. in mature transformed tobacco plants, the rold-gus genes were expressed strongly in roots, and to much lower levels in stems and le ...19957581519
the plant oncogenes rola, b, and c from agrobacterium rhizogenes. effects on morphology, development, and hormone metabolism. 19957581667
quantifying polyamines in agrobacterium rhizogenes strains and in ri plasmid transformed cells. 19957581668
deletion analysis and localization of sbprp1, a soybean cell wall protein gene, in roots of transgenic tobacco and cowpea.sbprp1 is a member of the soybean (glycine max l. merr) proline-rich cell wall protein family and is expressed at high levels in root tissue. to characterize the sequences required for this expression, we have fused 1.1 kb of upstream flanking dna sequence from an sbprp1 genomic clone to a gene encoding beta-glucuronidase (gus). this construct was introduced into tobacco using agrobacterium tumefaciens-mediated transformation. histochemical staining of gus activity in transgenic tobacco indicate ...19937678758
impaired photoassimilate partitioning caused by phloem-specific removal of pyrophosphate can be complemented by a phloem-specific cytosolic yeast-derived invertase in transgenic plants.constitutive expression of the escherichia coli ppa gene encoding inorganic pyrophosphatase resulted in sugar accumulation in source leaves and stunted growth of transgenic tobacco plants. the reason for this phenotype was hypothesized to be reduced sucrose utilization and loading into the phloem. to study the role of ppi in phloem cells, a chimeric gene was constructed using the phloem-specific rolc promoter of agrobacterium rhizogenes to drive the expression of the ppa gene. removal of cytosol ...19957734961
expression of agrobacterium rhizogenes auxin biosynthesis genes in transgenic tobacco plants.plant oncogenes aux1 and aux2 carried by the tr-dna of agrobacterium rhizogenes strain a4 encode two enzymes involved in the auxin biosynthesis pathway in transformed plant cells. the short divergent promoter region between the two aux-coding sequences contains the main regulatory elements. this region was fused to the uida reporter gene and introduced into nicotiana tabacum in order to investigate the regulation and the tissue specificity of these genes. neither wound nor hormone induction coul ...19957787177
biosynthesis of defense-related proteins in transformed root cultures of trichosanthes kirilowii maxim. var japonicum (kitam.).we have established transformed ("hairy") root cultures from trichosanthes kirilowii maxim. var japonicum kitam. (cucurbitaceae) and four related species to study the biosynthesis of the ribosome-inactivating protein trichosanthin (tcn) and other root-specific defense-related plant proteins. stable, fast-growing root clones were obtained for each species by infecting in vitro grown plantlets with agrobacterium rhizogenes american type culture collection strain 15834. each species accumulated rep ...19947824645
differentiation of brucella abortus bv. 1, 2, and 4, brucella melitensis, brucella ovis, and brucella suis bv. 1 by pcr.several pcr assays which identify the genus brucella but do not discriminate among species have been reported. we describe a pcr assay that comprises five oligonucleotide primers which can identify selected biovars of four species of brucella. individual biovars within a species are not differentiated. the assay can identify three biovars (1, 2, and 4) of b. abortus, all three biovars of b. melitensis, biovar 1 of b. suis, and all b. ovis biovars. these biovars include all of the brucella specie ...19947852552
the expression of a chimeric phaseolus vulgaris nodulin 30-gus gene is restricted to the rhizobially infected cells in transgenic lotus corniculatus nodules.in phaseolus vulgaris there is a nodulin family, npv30, of ca. 30 kda, as detected in an in vitro translation assay [2]. we isolated a gene (npv30-1) for one of the members of this family. the nucleotide sequence of the promoter of npv30-1 contains nodule-specific motifs common to other late nodulin genes. the promoter was fused to the gus reporter gene; this chimeric fusion was introduced into lotus corniculatus via agrobacterium rhizogenes transformation. gus activity was only detected in the ...19947858234
identification of several soybean cytosolic glutamine synthetase transcripts highly or specifically expressed in nodules: expression studies using one of the corresponding genes in transgenic lotus corniculatus.a dna fragment containing sequences hybridizing to the 5' region of gs15, a gene encoding soybean cytosolic glutamine synthetase, was isolated from a soybean genomic library. mapping and partial sequence analysis of the genomic clone revealed that it encodes a cytosolic gs gene, gs21, which is different from gs15. in parallel, a number of cdna clones encoding cytosolic gs were isolated using the coding region of pgs20 as a probe (pgs20 is a cdna clone which corresponds to a transcript of the gs1 ...19957865779
identification of the agrobacterium tumefaciens c58 t-dna genes e and f and their impact on crown gall tumour formation.dna sequence analysis of the 4.4 kilobases (kb) eco ri fragment 14 from t-dna of agrobacterium tumefaciens c58 revealed three open reading frames. one of them (945 bp) was supposed to encode the transcript e, the function of which has not been identified to date. furthermore, a so far undescribed open reading frame (1035 bp) was identified, located in the centre of the eco ri fragment 14 and termed gene f. the third open reading frame encoded the carboxy-terminal part of the agrocinopine synthas ...19957865795
a new agrobacterium strain isolated from aerial tumors on ficus benjamina l.crown gall tumors, collected from branches of 1-year-old weeping fig (ficus benjamina l.) trees, yielded both tumorigenic and nonpathogenic agrobacteria. on the basis of classical diagnostic tests, the nonpathogenic strains were identified as agrobacterium tumefaciens, whereas the tumorigenic strains could not be assigned to any of the known terrestrial agrobacterium spp. the tumorigenic strains also differed from other members of the genus by producing more acid from mannitol. according to clus ...19957887626
analysis of the lupin nodulin-45 promoter: conserved regulatory sequences are important for promoter activity.the promoter from the lupinus angustifolius late nodulin gene, nodulin-45, has been analysed to identify cis-elements and trans-acting factors. various regions of the nodulin-45 promoter, fused to the luciferase reporter gene, were introduced into lotus roots using an agrobacterium rhizogenes, transformation procedure. the transgenic roots were then nodulated. the promoter region a (-172 to +13, relative to the transcription start site) was capable of directing low-level expression of the report ...19957894011
bacterial plant oncogenes: the rol genes' saga.the rol genes are part of the t-dna which is transferred by agrobacterium rhizogenes in plant cells, causing neoplastic growth and differentiation. each of these bacterial oncogenes deeply influences plant development and is finely regulated once transferred into the plant host. both from the study of the effects and biochemical function of the rol genes and from the analysis of their regulation, important insight in plant development can be derived. some of the most intriguing aspects of past, ...19947896140
rol genes of agrobacterium rhizogenes cucumopine strain: sequence, effects and pattern of expression.by sequencing the central region of the cucumopine-type t-dna of agrobacterium rhizogenes strain 2659, we identified three open reading frames homologous, to different extents, to orfs 10, 11 and 12 (rola, b and c) of the agropine-type (1855) t-dna. recombinant agrobacterium strains encompassing the orfs of 2659 t-dna--which we refer to as rol alpha, beta and gamma--were utilized to infect carrot discs and to obtain transgenic tobacco plants, in order to compare the morphogenetic capabilities to ...19947948887
alterations of auxin perception in rolb-transformed tobacco protoplasts. time course of rolb mrna expression and increase in auxin sensitivity reveal multiple control by auxin.expression and physiological effects of the root-inducing rolb gene of agrobacterium rhizogenes t-dna were studied simultaneously in tobacco (nicotiana tabacum) mesophyll protoplasts. the kinetic study of the expression of rolb mrna following exogenous auxin application showed that auxin transiently stimulated rolb expression, with mrna levels starting to accumulate 6 to 9 h after auxin was supplied and increasing 300-fold after 12 to 18 h. the parallel study of the auxin sensitivity of rolb-tra ...19947972494
a new open reading frame, encoding a putative regulatory protein, in agrobacterium rhizogenes t-dna.we report the presence of an open reading frame, named orf13a, encoding a putative regulatory protein on the t-dna of agrobacterium rhizogenes 8196 ri plasmid. homologous orfs are present at the same location in two other types of ri plasmids. we present evidence that orf13a is transcriptionally active. expression of orf13a was investigated by analysis of glucuronidase (gus) activity in transgenic tobacco containing an orf13agus fusion. the gene fusion was expressed at higher level in roots than ...19947987690
bryonolic acid production in hairy roots of trichosanthes kirilowii max. var japonica kitam. transformed with agrobacterium rhizogenes and its cytotoxic activity.the hairy roots of trichosanthes kirilowii max, var. japonica kitam. were induced by agrobacterium rhizogenes (tcc 15834) on sterile shoots. the axenic culture of hairy roots proliferated 30 to 60-fold based on the initial fresh weight after three weeks of culture in murashige & skoog liquid media. bryonolic acid as the main triterpenoid was isolated in a high yield, together with chondrillasterol from the hairy roots of this plant. bryonolic acid showed strong inhibition of the growth of b-16 m ...19948004724
sequence of the cellular t-dna in the untransformed genome of nicotiana glauca that is homologous to orfs 13 and 14 of the ri plasmid and analysis of its expression in genetic tumours of n. glauca x n. langsdorffii.a region homologous to the tl-dna of agrobacterium rhizogenes was previously detected in the genome of untransformed nicotiana glauca and designated cellular t-dna (ct-dna). subsequently, part of this region was sequenced and two genes, which corresponded to rolb and rolc and were named ngrolb and ngrolc, were found. we have now sequenced a region of the ct-dna other than the region that includes ngrolb and c and we have found two other open reading frames (orfs), ngorf13 and ngorf14. these orfs ...19948028588
the rolc promoter of agrobacterium rhizogenes ri plasmid is activated by sucrose in transgenic tobacco plants.the 5'-upstream region of the rolc gene of the ri plasmid is expressed specifically in phloem cells of transgenic higher plants. in this study, we demonstrated that the rolc promoter is activated by sucrose in phloem cells of transgenic tobacco seedlings bearing rolc promoter-uida chimeric fusion gene. since the rolc promoter is not activated by sorbitol, sucrose metabolism rather than osmotic pressure exerted by the disaccharide may be responsible for induction. thus, experiments using 5'-upstr ...19948041357
changing root system architecture through inhibition of putrescine and feruloyl putrescine accumulation.plant roots provide anchorage and absorb the water and minerals necessary for photosynthesis in the aerial parts of the plant. since plants are sessile organisms, their root systems must forage for resources in heterogeneous soils through differential branching and elongation [(1988) funct. ecol. 2, 345-351; (1991) plant roots: the hidden half, pp. 3-25, marcel dekker, ny]. adaptation to drought, for instance, can be facilitated by increased root growth and penetration. root systems thus develop ...19948143867
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