| generation of composite plants using agrobacterium rhizogenes. | limitations in transformation capability can be a significant barrier in making advances in our understanding of gene function through the use of transgenics. to this end we have developed both tissue culture and non-tissue culture-based methodologies for the production of transgenic roots on wild-type shoots (composite plants). composite plants are generated by inoculating wild-type shoots with agrobacterium rhizogenes, which subsequently induces the formation of transgenic roots. the composite ... | 2006 | 16988342 |
| hairy roots induced by agrobacterium rhizogenes and production of regenerative plants in hairy root cultures in maize. | hairy roots of maize were induced by infecting 15-d calli with agrobacterium rhizogenes. the hairy roots cultured in hormone-free media showed the vigorous growth and typical hairy root features. the regenerated plants were produced from hairy roots in ms media supplemented with 1.6 mg/l zt and 0.4 mg/l naa. the pcr-southern hybridization demonstrated that t-dna had been integrated into the chromosome of regenerated plants. | 2006 | 16989275 |
| tropane alkaloids production in transgenic hyoscyamus niger hairy root cultures over-expressing putrescine n-methyltransferase is methyl jasmonate-dependent. | the cdna from nicotiana tabacum encoding putrescine n-methyltransferase (pmt), which catalyzes the first committed step in the biosynthesis of tropane alkaloids, has been introduced into the genome of a scopolamine-producing hyoscyamus niger mediated by the disarmed agrobacterium tumefaciens strain c58c1, which also carries agrobacterium rhizogenes ri plasmid pria4, and expressed under the control of the camv 35s promoter. hairy root lines transformed with pmt presented fivefold higher pmt activ ... | 2007 | 17004056 |
| agrobacterium rhizogenes galls protein contains domains for atp binding, nuclear localization, and type iv secretion. | agrobacterium tumefaciens and agrobacterium rhizogenes are closely related plant pathogens that cause different diseases, crown gall and hairy root. both diseases result from transfer, integration, and expression of plasmid-encoded bacterial genes located on the transferred dna (t-dna) in the plant genome. bacterial virulence (vir) proteins necessary for infection are also translocated into plant cells. transfer of single-stranded dna (ssdna) and vir proteins requires a type iv secretion system, ... | 2006 | 17012398 |
| accumulation of p-hydroxybenzoic acid in hairy roots of daucus carota. | we report here the accumulation of p-hydroxybenzoic acid in agrobacterium rhizogenes-induced hairy root cultures of daucus carota. this phenolic acid finds application in food, pharmaceutical and polymer industries. metabolic profiling of phenolics by hplc/esi-ms from these hairy roots showed a considerable amount of p-hydroxybenzoic acid accumulation both in cytosol and in the cell wall. analyses of hcl and naoh treated soluble phenolic fractions resulted in the elution of peaks with same reten ... | 2007 | 17027117 |
| the medicago truncatula cre1 cytokinin receptor regulates lateral root development and early symbiotic interaction with sinorhizobium meliloti. | legumes develop different types of lateral organs from their primary root, lateral roots and nodules, the latter depending on a symbiotic interaction with sinorhizobium meliloti. phytohormones have been shown to function in the control of these organogeneses. however, related signaling pathways have not been identified in legumes. we cloned and characterized the expression of medicago truncatula genes encoding members of cytokinin signaling pathways. rna interference of the cytokinin receptor ho ... | 2006 | 17028204 |
| [ri plasmid transformation of glycyrrhiza uralensis and effects of some factors on growth of hairy roots]. | to study the induction of hairy roots of glycyrrhiza uralensis and effect of some physical as well as chemical factors on the growth of hairy roots. | 2006 | 17048620 |
| agrobacterium tumefaciens and agrobacterium rhizogenes transformed roots of the parasitic plant triphysaria versicolor retain parasitic competence. | parasitic plants in the orobanchaceae invade roots of neighboring plants to rob them of water and nutrients. triphysaria is facultative parasite that parasitizes a broad range of plant species including maize and arabidopsis. in this paper we describe transient and stable transformation systems for triphysaria versicolor fischer and c. meyer. agrobacterium tumefaciens and agrobacterium rhizogenes were both able to transiently express a gus reporter in triphysaria seedlings following vacuum infil ... | 2007 | 17053892 |
| [study on establishment of system with high frequency for genetic transformation of phellodendron chinese and plant regeneration]. | to establish an effective system for genetic transformation of phellodendron chinese by agrobacterium rhizogenes. | 2006 | 17058995 |
| caffeic acid derivatives production by hairy root cultures of echinacea purpurea. | inoculation of leaf explants of echinacea purpurea (moench) with agrobacterium rhizogenes induced hairy roots with the capacity to produce biologically active caffeic acid derivatives (cads), especially cichoric acid. the kinetics of growth, the uptake of macronutrients, and the accumulation of cads were investigated in heterotrophically cultured hairy roots for a 50 day period. a maximum of 12.2 g l(-1) dry biomass was achieved in ms nutrients supplemented with 30 g l(-1) sucrose on day 40. the ... | 2006 | 17061821 |
| lotus japonicus nodulation requires two gras domain regulators, one of which is functionally conserved in a non-legume. | a new nodulation-defective mutant of lotus japonicus does not initiate nodule cortical cell division in response to mesorhizobium loti, but induces root hair deformation, nod factor-induced calcium spiking, and mycorrhization. this phenotype, together with mapping data, suggested that the mutation could be in the ortholog of the medicago truncatula nsp1 gene (mtnsp1). the sequence of the orthologous gene (ljnsp1) in the l. japonicus mutant (ljnsp1-1) revealed a mutation causing a premature stop ... | 2006 | 17071642 |
| rhizobium lusitanum sp. nov. a bacterium that nodulates phaseolus vulgaris. | the species phaseolus vulgaris is a promiscuous legume nodulated by several species of the family rhizobiaceae. during a study of rhizobia nodulating this legume in portugal, we isolated several strains that nodulate p. vulgaris effectively and also macroptilium atropurpureum and leucaena leucocephala, but they form ineffective nodules in medicago sativa. according to phylogenetic analysis of the 16s rrna gene sequence, the strains from this study belong to the genus rhizobium, with rhizobium rh ... | 2006 | 17082403 |
| changes in morphological phenotypes and withanolide composition of ri-transformed roots of withania somnifera. | developmental variability was introduced into withania somnifera using genetic transformation by agrobacterium rhizogenes, with the aim of changing withasteroid production. inoculation of w. somnifera with a. rhizogenes strains lba 9402 and a4 produced typical transformed root lines, transformed callus lines, and rooty callus lines with simultaneous root dedifferentiation and redifferentiation. these morphologically distinct transformed lines varied in t-dna content, growth rates, and withastero ... | 2007 | 17103214 |
| novel type iv secretion system involved in propagation of genomic islands. | type iv secretion systems (t4sss) mediate horizontal gene transfer, thus contributing to genome plasticity, evolution of infectious pathogens, and dissemination of antibiotic resistance and other virulence traits. a gene cluster of the haemophilus influenzae genomic island icehin1056 has been identified as a t4ss involved in the propagation of genomic islands. this t4ss is novel and evolutionarily distant from the previously described systems. mutation analysis showed that inactivation of key ge ... | 2007 | 17122343 |
| novel type iv secretion system involved in propagation of genomic islands. | type iv secretion systems (t4sss) mediate horizontal gene transfer, thus contributing to genome plasticity, evolution of infectious pathogens, and dissemination of antibiotic resistance and other virulence traits. a gene cluster of the haemophilus influenzae genomic island icehin1056 has been identified as a t4ss involved in the propagation of genomic islands. this t4ss is novel and evolutionarily distant from the previously described systems. mutation analysis showed that inactivation of key ge ... | 2007 | 17122343 |
| a cdpk isoform participates in the regulation of nodule number in medicago truncatula. | medicago spp. are able to develop root nodules via symbiotic interaction with sinorhizobium meliloti. calcium-dependent protein kinases (cdpks) are involved in various signalling pathways in plants, and we found that expression of mtcpk3, a cdpk isoform present in roots of the model legume medicago truncatula, is regulated during the nodulation process. early inductions were detected 15 min and 3-4 days post-inoculation (dpi). the very early induction of cpk3 messengers was also present in inocu ... | 2006 | 17132148 |
| [induction of hairy roots and anthraquinone production in rheum palmatum]. | to study the induction of hairy roots and anthraquinone production in rheum palmatum. | 2006 | 17144464 |
| agrobacterium rhizogenes transformation of the phaseolus spp.: a tool for functional genomics. | a fast, reproducible, and efficient transformation procedure employing agrobacterium rhizogenes was developed for phaseolus vulgaris l. wild accessions, landraces, and cultivars and for three other species belonging to the genus phaseolus: p. coccineus, p. lunatus, and p. acutifolius. induced hairy roots are robust and grow quickly. the transformation frequency is between 75 and 90% based on the 35-s promoter-driven green fluorescent protein and beta-glucuronidase expression reporter constructs. ... | 2006 | 17153923 |
| the rolb gene-induced overproduction of resveratrol in vitis amurensis transformed cells. | resveratrol is a stilbene, which prevents carcinogenesis at stages of tumor initiation, promotion and progression. in the present investigation, we developed cell cultures of wild-growing grape (vitis amurensis rupr.). the cultures produced low levels of resveratrol, up to 0.026% dry wt., i.e., comparable to levels reported for other plant cell cultures previously established. different methods commonly used to increase secondary metabolite production (cell selection, elicitor treatments and add ... | 2007 | 17166613 |
| assessing potential dietary toxicity of heavy metals in selected vegetables and food crops. | heavy metals, such as cadmium, copper, lead, chromium and mercury, are important environmental pollutants, particularly in areas with high anthropogenic pressure. their presence in the atmosphere, soil and water, even in traces can cause serious problems to all organisms, and heavy metal bioaccumulation in the food chain especially can be highly dangerous to human health. heavy metals enter the human body mainly through two routes namely: inhalation and ingestion, ingestion being the main route ... | 2007 | 17173356 |
| assessing potential dietary toxicity of heavy metals in selected vegetables and food crops. | heavy metals, such as cadmium, copper, lead, chromium and mercury, are important environmental pollutants, particularly in areas with high anthropogenic pressure. their presence in the atmosphere, soil and water, even in traces can cause serious problems to all organisms, and heavy metal bioaccumulation in the food chain especially can be highly dangerous to human health. heavy metals enter the human body mainly through two routes namely: inhalation and ingestion, ingestion being the main route ... | 2007 | 17173356 |
| antimicrobial activity of diterpenoids from hairy roots of salvia sclarea l.: salvipisone as a potential anti-biofilm agent active against antibiotic resistant staphylococci. | the antimicrobial activities of crude dichloromethane fractions from acetone extracts of agrobacterium rhizogenes transformed roots and roots of field-grown plants of salvia sclarea as well as four pure abietane diterpenoids isolated from the hairy root cultures were determined. the growth of gram-positive bacteria (staphylococcus aureus, s. epidermidis, enterococcus faecalis) but not gram-negative ones (escherichia coli, pseudomonas aeruginosa) or pathogenic fungi (candida albicans) was inhibit ... | 2007 | 17190643 |
| 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 |
| accumulation of rare phenylpropanoids in agrobacterium rhizogenes transformed root cultures of coreopsis tinctoria. | | 1990 | 17221456 |
| production of forskolin by axenic coleus forskohlii roots cultivated in shake flasks and 20-l glass jar bioreactors*. | root cultures of coleus forskohlii briq. were initiated from primary callus or iba-treated suspension cultures and maintained on gamborg's b5 medium containing 1 mg/l iba. transformed root cultures were established by infecting surface-sterilized leaves with agrobacterium rhizogenes strain 15834. transformation was confirmed by mannopine detection. these cultures displayed the typical characteristics of hairy root cultures, with the sole exceptions of slow growth in hormone-free medium and accel ... | 1992 | 17226482 |
| rox1, a gene induced by rolb, is involved in procambial cell proliferation and xylem differentiation in tobacco stamen. | the agrobacterium rhizogenes oncogene rolb mimics the effects of auxin in that it increases the sensitivity of transformed cells to this hormone. here we isolated a tobacco gene, rox1, acting downstream of rolb. we show that plants with reduced levels of rox1 mrna, due to the expression of a 35s-driven rox1-antisense construct, have flowers with stamens and pistils longer than normal because of an increased number of cells. localized expression of rolb in anthers results in overexpression of rox ... | 2007 | 17233794 |
| tropane alkaloid production in transformed root cultures of brugmansia candida. | transformed root cultures of brugmansia candida were established by infection with agrobacterium rhizogenes lba 9402. several clones with different growth index and tropane alkaloid pattern and content were obtained and two were examined in depth. the alkaloid content and pattern changed during the time course. at 21 days of culture clone 1 revealed an alkaloid spectrum dominated by 3alpha-acetoxytropane (about 50% of the total alkaloid) and hyoscyamine (about 25%), with a ratio of hyoscyamine t ... | 1993 | 17236002 |
| tropane alkaloids in transformed roots of datura quercifolia. | hairy root cultures of datura quercifolia were established following infection with agrobacterium rhizogenes strain lba 9402. eight tropane alkaloids were identified in the hairy roots, hyoscyamine being the major constituent. the growth and the hyoscyamine content of transformed roots were investigated under various conditions. gamborg b5, murashige and skoog, and woody plant media were tested. gamborg b5 medium was the best for growth as well as for hyoscyamine accumulation. the influence of s ... | 1994 | 17236033 |
| content of thiophenes in transformed root cultures of argentinian species of tagetes. | the presence of thiophenes in four argentinian species of tagetes was studied. t. terniflora hbk and t. minuta l. seedlings contain 5-(4-hydroxy-1-butynyl)-2-2'-bithienyl (bbtoh); 5-(4-acetoxy-1-butynyl)-2,2'-bithienyl (bbtoac), while t. campanulata griseb and t. laxa cabrera seedlings also accumulated bbt and alpha-t. from the four tagetes species tested only t. laxa was able to produce transformed roots when infected with agrobacterium rhizogenes lba 9402. several clones of transformed roots w ... | 1994 | 17236044 |
| an ire-like agc kinase gene, mtire, has unique expression in the invasion zone of developing root nodules in medicago truncatula. | the agc protein kinase family (camp-dependent protein kinases a, cgmp-dependent protein kinases g, and phospholipid-dependent protein kinases c) have important roles regulating growth and development in animals and fungi. they are activated via lipid second messengers by 3-phosphoinositide-dependent protein kinase coupling lipid signals to phosphorylation of the agc kinases. these phosphorylate downstream signal transduction protein targets. agc kinases are becoming better studied in plants, esp ... | 2007 | 17237187 |
| silencing of pr-10-like proteins in medicago truncatula results in an antagonistic induction of other pr proteins and in an increased tolerance upon infection with the oomycete aphanomyces euteiches. | recent studies on the root proteome of medicago truncatula (gaertn.) showed an induction of pathogenesis-related (pr) proteins of the class 10 after infection with the oomycete pathogen aphanomyces euteiches (drechs.). to get insights into the function of these proteins during the parasitic root-microbe association, a gene knockdown approach using rnai was carried out. agrobacterium rhizogenes-mediated transformation of m. truncatula roots led to a knockdown of the medicago pr10-1 gene in transg ... | 2007 | 17237953 |
| agrobacterium rhizogenes-mediated transformation of artemisia annua: production of transgenic plants. | transgenic hairy roots were induced in the leaves of artemisia annua by treatment with the lba 9402 strain of agrobacterium rhizogenes. the axenic hairy root cultures were found to produce the sesquiterpenes artemisinic acid and arteannuin b. the hairy root cultures were observed to spontaneously regenerate into plantlets on solid hormone-free ms medium. the regenerated plants had phenotypic characteristics typical to the transformed plants. among the plants of the age of one month in culture, t ... | 1997 | 17252369 |
| withanolide composition and in vitro culture of italian withania somnifera. | from italian plants of withania somnifera six withanolides were isolated, whose structures allowed us to assign the italian race of w. somnifera to the israel chemotype iii. in vitro cultures of italian w. somnifera under different conditions were obtained, as well as infection by agrobacterium rhizogenes. hplc analysis of in vitro derived tissues showed low contents of withanolides. | 1996 | 17252448 |
| withanolide production by root cultures of withania somnifera transformed with agrobacterium rhizogenes. | transformed root cultures of withania somnifera dunal (solanaceae) were obtained by infecting shoots cultured in vitro with agrobacterium rhizogenes lba 9402. they grew axenically in the absence of exogenous plant growth regulators in murashige and skoog's medium containing 3% (w/v) sucrose. the root cultures synthesized several withanolides of which withanolide d was isolated and identified. transformed root (clone hr (1)) showed a growth index of 20.07 and a withanolide d yield of 0.30 mg g(-1 ... | 1996 | 17252504 |
| influence of agrobacterium rhizogenes strains on biomass and alkaloid productivity in hairy root lines of hyoscyamus muticus and h. albus *. | using leaf explants of in vitro grown hyoscyamus albus and h. muticus plantlets, hairy roots were induced following inoculation with agrobacterium rhizogenes strains a (4) and lba-9402. the transformed roots, appearing after 14 - 17 days incubation on hormone-free ms medium containing 1 g/l cephalexin, were excised and maintained in the same medium. ten randomly selected hairy root lines from each bacterial treatment of the two plant systems were compared for growth and alkaloid production in ha ... | 1999 | 17260237 |
| alkaloid production by transformed root cultures of cinchona ledgeriana. | transformed root cultures of cinchona ledgeriana have been generated by infecting shoots cultured in vitro with agrobacterium rhizogenes lba9402. these root cultures grow axenically in the absence of antibiotics or exogenous plant growth regulators in media containing gamborg b5 salts at half or full strength with 3% (w/v) sucrose as the carbon source. they show a 6- to 8-fold increase in fresh weight in 28 days. transformation has been confirmed by southern blotting using [ (32)p]-labelled frag ... | 1989 | 17262435 |
| production of hyoscyamine by 'hairy root' cultures of datura stramonium. | 'hairy root' cultures of datura stramonium were established following infection of aseptic leaves with agrobacterium rhizogenes. transformation was confirmed by southern blotting using [ (32)p]-labelled fragments of the t-dna as probes. the transformed cultures grew in the absence of added phytohormones and cell mass increased 55-fold during 28 days incubation. hyoscyamine was a major component of the alkaloid fraction and accounted for at least 0.3% of the dry matter, comparable to pot-grown pl ... | 1987 | 17269071 |
| [hairy roots induction of phellodendron chinense and production of its active constituents]. | to introduce the hairy roots of phellodendron chinense and determine the content of its active constituents. | 2006 | 17285981 |
| the mtmmpl1 early nodulin is a novel member of the matrix metalloendoproteinase family with a role in medicago truncatula infection by sinorhizobium meliloti. | we show here that mtmmpl1, a medicago truncatula nodulin gene previously identified by transcriptomics, represents a novel and specific marker for root and nodule infection by sinorhizobium meliloti. this was established by determining the spatial pattern of mtmmpl1 expression and evaluating gene activation in the context of various plant and bacterial symbiotic mutant interactions. the mtmmpl1 protein is the first nodulin shown to belong to the large matrix metalloendoproteinase (mmp) family. w ... | 2007 | 17293436 |
| hairy root type plant in vitro systems as sources of bioactive substances. | "hairy root" systems, obtained by transforming plant tissues with the "natural genetic engineer" agrobacterium rhizogenes, have been known for more than three decades. to date, hairy root cultures have been obtained from more than 100 plant species, including several endangered medicinal plants, affording opportunities to produce important phytochemicals and proteins in eco-friendly conditions. diverse strategies can be applied to improve the yields of desired metabolites and to produce recombin ... | 2007 | 17294182 |
| nucleoporin85 is required for calcium spiking, fungal and bacterial symbioses, and seed production in lotus japonicus. | in lotus japonicus, seven genetic loci have been identified thus far as components of a common symbiosis (sym) pathway shared by rhizobia and arbuscular mycorrhizal fungi. we characterized the nup85 mutants (nup85-1, -2, and -3) required for both symbioses and cloned the corresponding gene. when inoculated with glomus intraradices, the hyphae managed to enter between epidermal cells, but they were unable to penetrate the cortical cell layer. the nup85-2 mutation conferred a weak and temperature- ... | 2007 | 17307929 |
| tissue distribution, core biosynthesis and diversification of pyrrolizidine alkaloids of the lycopsamine type in three boraginaceae species. | three species of the boraginaceae were studied: greenhouse-grown plants of heliotropium indicum and agrobacterium rhizogenes transformed roots cultures (hairy roots) of cynoglossum officinale and symphytum officinale. the species-specific pyrrolizidine alkaloid (pa) profiles of the three systems were established by gc-ms. all pas are genuinely present as n-oxides. in h. indicum the tissue-specific pa distribution revealed the presence of pas in all tissues with the highest levels in the inflores ... | 2007 | 17320124 |
| characterization of vascular-specific rss1 and rolc promoters for their utilization in engineering plants to develop resistance against hemipteran insect pests. | rice sucrose synthase1, rss1 (isolated from rice) and rolc (isolated from agrobacterium rhizogenes) promoters were evaluated by binding analyses of their respective cis-elements with host nuclear transcription factors. the expression profile of an insecticidal protein driven by these promoters in transgenic plants was monitored. motif-search analysis with available phloem-specific promoter sequences revealed the presence of two boxii elements in rss1. an octopine synthase element, a stem-specifi ... | 2007 | 17323077 |
| salidroside production by hairy roots of rhodiola sachalinensis obtained after transformation with agrobacterium rhizogenes. | hairy roots induced by agrobacterium rhizogenes grow faster, and are considered as genetically stable. these hairy roots can be used as an interesting material for the production of secondary metabolites of pharmaceutical value. salidroside has been identified as the major compounds from the roots of rhodiola sachalinensis a. bor. here, we provide an update that adds new perspectives on the prospects and challenges of producing salidroside from hairy roots induced by agrobacterium rhizogene in r ... | 2007 | 17329834 |
| stable transformation and long-term maintenance of transgenic taxus cell suspension cultures. | a cell line of taxus cuspidata has been transformed with wild-type agrobacterium rhizogenes atcc strain 15834 containing binary vector pcambia1301 and, separately, with a. tumefaciens strain eha105 containing binary vector pcambia1305.2. additionally, a cell line of t. chinensis has been transformed with wild-type a. rhizogenes atcc strain 25818 containing binary vector pcambia1301. the two transgenic t. cuspidata cell lines have been maintained in culture for more than 20 months, and the transg ... | 2007 | 17333018 |
| cell-cell communication in the plant pathogen agrobacterium tumefaciens. | the plant pathogen agrobacterium tumefaciens induces the formation of crown gall tumours at wound sites on host plants by directly transforming plant cells. this disease strategy benefits the bacteria as the infected plant tissue produces novel nutrients, called opines, that the colonizing bacteria can use as nutrients. almost all of the genes that are required for virulence, and all of the opine uptake and utilization genes, are carried on large tumour-inducing (ti) plasmids. the observation mo ... | 2007 | 17360279 |
| hairy root culture for mass-production of high-value secondary metabolites. | plant cell cultivations are being considered as an alternative to agricultural processes for producing valuable phytochemicals. since many of these products (secondary metabolites) are obtained by direct extraction from plants grown in natural habitat, several factors can alter their yield. the use of plant cell cultures has overcome several inconveniences for the production of these secondary metabolites. organized cultures, and especially root cultures, can make a significant contribution in t ... | 2007 | 17364688 |
| medicago truncatula nin is essential for rhizobial-independent nodule organogenesis induced by autoactive calcium/calmodulin-dependent protein kinase. | the symbiotic association between legumes and nitrogen-fixing bacteria collectively known as rhizobia results in the formation of a unique plant root organ called the nodule. this process is initiated following the perception of rhizobial nodulation factors by the host plant. nod factor (nf)-stimulated plant responses, including nodulation-specific gene expression, is mediated by the nf signaling pathway. plant mutants in this pathway are unable to nodulate. we describe here the cloning and char ... | 2007 | 17369436 |
| a symbiotic plant peroxidase involved in bacterial invasion of the tropical legume sesbania rostrata. | aquatic nodulation on the tropical legume sesbania rostrata occurs at lateral root bases via intercellular crack-entry invasion. a gene was identified (srprx1) that is transiently up-regulated during the nodulation process and codes for a functional class iii plant peroxidase. the expression strictly depended on bacterial nodulation factors (nfs) and could be modulated by hydrogen peroxide, a downstream signal for crack-entry invasion. expression was not induced after wounding or pathogen attack ... | 2007 | 17384158 |
| rnai silencing of genes for elicitation or biosynthesis of 5-deoxyisoflavonoids suppresses race-specific resistance and hypersensitive cell death in phytophthora sojae infected tissues. | isoflavonoids are thought to play an important role in soybean (glycine max) resistance to phytophthora sojae. this was addressed by silencing two genes for their biosynthesis and a third gene controlling their elicitation. silencing of genes for isoflavone synthase (ifs) or chalcone reductase (chr) was achieved in soybean roots through an agrobacterium rhizogenes-mediated rnai approach. effectiveness of silencing was followed both by quantitative reverse transcriptase-polymerase chain reaction ... | 2007 | 17416637 |
| regulation of arbuscular mycorrhization by carbon. the symbiotic interaction cannot be improved by increased carbon availability accomplished by root-specifically enhanced invertase activity. | the mutualistic interaction in arbuscular mycorrhiza (am) is characterized by an exchange of mineral nutrients and carbon. the major benefit of am, which is the supply of phosphate to the plant, and the stimulation of mycorrhization by low phosphate fertilization has been well studied. however, less is known about the regulatory function of carbon availability on am formation. here the effect of enhanced levels of hexoses in the root, the main form of carbohydrate used by the fungus, on am forma ... | 2007 | 17416641 |
| flavone synthases from medicago truncatula are flavanone-2-hydroxylases and are important for nodulation. | flavones are important copigments found in the flowers of many higher plants and play a variety of roles in plant adaptation to stress. in medicago species, flavones also act as signal molecules during symbiotic interaction with the diazotropic bacterium sinorhizobium meliloti. they are the most potent nod gene inducers found in root exudates. however, flavone synthase ii (fns ii), the key enzyme responsible for flavone biosynthesis, has not been characterized in medicago species. we cloned two ... | 2007 | 17434990 |
| agrobacterium rhizogenes-mediated transformation of soybean to study root biology. | this protocol is used to induce transgenic roots on soybean to study the function of genes required in biological processes of the root. young seedlings with unfolded cotyledons are infected at the cotyledonary node and/or hypocotyl with agrobacterium rhizogenes carrying the gene construct to be tested and the infection sites are kept in an environment of high humidity. when the emerged hairy roots can support the plants, the main roots are removed and the transgenic roots can be tested. using t ... | 2007 | 17446894 |
| resistance to root-knot nematode in tomato roots expressing a nematicidal bacillus thuringiensis crystal protein. | our laboratory has demonstrated previously that bacillus thuringiensis (bt) crystal (cry) proteins present in the cry5 and cry6 subclades intoxicate free-living nematodes. in this study, we tested whether the expression of nematicidal cry6a in transgenic plants provided protection against plant-parasitic nematodes. as bacterial codon usage is incompatible with expression in plants, two different codon-modified cry6a genes were synthesized for expression in plants. one was designed by maintaining ... | 2007 | 17451491 |
| [effects of methyl jasmonat on accumulation and release of tanshinones in suspension cultures of salvia miltiorrhiza hairy root]. | to study the effects of methyl jasmonate (mj) on the accumulation and release of tanshinones in suspension cultures of salvia miltiorrhiza hairy roots. | 2007 | 17455461 |
| overlap of proteome changes in medicago truncatula in response to auxin and sinorhizobium meliloti. | we used proteome analysis to identify proteins induced during nodule initiation and in response to auxin in medicago truncatula. from previous experiments, which found a positive correlation between auxin levels and nodule numbers in the m. truncatula supernodulation mutant sunn (supernumerary nodules), we hypothesized (1) that auxin mediates protein changes during nodulation and (2) that auxin responses might differ between the wild type and the supernodulating sunn mutant during nodule initiat ... | 2007 | 17468210 |
| auxin and nitric oxide control indeterminate nodule formation. | rhizobia symbionts elicit root nodule formation in leguminous plants. nodule development requires local accumulation of auxin. both plants and rhizobia synthesise auxin. we have addressed the effects of bacterial auxin (iaa) on nodulation by using sinorhizobium meliloti and rhizobium leguminosarum bacteria genetically engineered for increased auxin synthesis. | 2007 | 17488509 |
| intron splicing in 5' untranslated region of the rola transcript in transgenic apple. | the rola gene encoded on the ri plasmid of agrobacterium rhizogenes causes developmental alterations, including dwarfing characteristics in the transgenic plants. in an attempt to introduce dwarfing characteristics into apple rootstocks for breeding purposes, the rola gene was incorporated into the apple rootstock m26 and obtained four transgenic clones. all the clones exhibited reduced growth compared to untransformed control plants but different degree of dwarfing and wrinkled leaves. in the p ... | 2008 | 17490782 |
| high efficiency poplar transformation. | with the completion of the poplar tree genome database, populus species have become one of the most useful model systems for the study of woody plant biology. populus tremuloides (quaking aspen) is the most wide-spread tree species in north america, and its rapid growth generates the most abundant wood-based biomass out of any other plant species. to study such beneficial traits, there is a need for easier and more efficient transformation procedures that will allow the study of large numbers of ... | 2007 | 17492451 |
| high efficiency agrobacterium rhizogenes-mediated transformation of saponaria vaccaria l. (caryophyllaceae) using fluorescence selection. | a highly efficient and convenient method for the agrobacterium rhizogenes-dependent production of transformed roots of saponaria vaccaria l. (caryophyllaceae) is described. the parameters tested and optimized include s. vaccaria cultivar, explant type, agrobacterium rhizogenes strain and culture conditions. for cotransformation using additional recombinant t-dna-containing a. rhizogenes strains, use of neomycin phosphotransferase and enhanced green fluorescent protein genes as selectable markers ... | 2007 | 17516073 |
| growth and rutin production in hairy root cultures of buckwheat (fagopyrum esculentum m.). | buckwheat (fagopyrum esculentum moench.) is a potentially important source of rutin, a natural flavonoid with antihyperglycemic, antihypertensive, and antioxidative properties. to examine in vitro production of rutin, we established a hairy root culture of buckwheat by infecting leaf explants with agrobacterium rhizogenes r1000, and tested the growth conditions and rutin production rates of these cultures. ten hairy root clones were established; their growth and rutin production rates ranged fro ... | 2007 | 17516253 |
| medicago lyk3, an entry receptor in rhizobial nodulation factor signaling. | rhizobia secrete nodulation (nod) factors, which set in motion the formation of nitrogen-fixing root nodules on legume host plants. nod factors induce several cellular responses in root hair cells within minutes, but also are essential for the formation of infection threads by which rhizobia enter the root. based on studies using bacterial mutants, a two-receptor model was proposed, a signaling receptor that induces early responses with low requirements toward nod factor structure and an entry r ... | 2007 | 17586690 |
| a generalized method for transfecting root epidermis uncovers endosomal dynamics in arabidopsis root hairs. | progress in analysing the cellular functions of many structural proteins has accelerated through the use of confocal microscopy together with transient gene expression. several methods for transient expression have been developed in the past few years, but their application has seen limited success beyond a few tractable species and tissues. we have developed a simple and efficient method to visualize fluorescent proteins in arabidopsis root epidermis using co-cultivation of seedlings with agrob ... | 2007 | 17610544 |
| the medicago truncatula dmi1 protein modulates cytosolic calcium signaling. | in addition to establishing symbiotic relationships with arbuscular mycorrhizal fungi, legumes also enter into a nitrogen-fixing symbiosis with rhizobial bacteria that results in the formation of root nodules. several genes involved in the development of both arbuscular mycorrhiza and legume nodulation have been cloned in model legumes. among them, medicago truncatula dmi1 (doesn't make infections1) is required for the generation of nucleus-associated calcium spikes in response to the rhizobial ... | 2007 | 17631529 |
| enhanced production of asiaticoside from hairy root cultures of centella asiatica (l.) urban elicited by methyl jasmonate. | transformed root ("hairy root") cultures have been shown to be a good model for the study of many secondary metabolites. however, economically important compounds such as asiaticoside and madecassoside are produced in insignificant amounts in the root of centella asiatica (l.) urban. to overcome this problem, c. asiatica was transformed using agrobacterium rhizogenes strain r1000 that harbors pcambia1302 encoding the hygromycin phosphotransferase (hpt) and green fluorescence protein (mgfp5) gene ... | 2007 | 17632725 |
| transcriptome profiling of lotus japonicus roots during arbuscular mycorrhiza development and comparison with that of nodulation. | to better understand the molecular responses of plants to arbuscular mycorrhizal (am) fungi, we analyzed the differential gene expression patterns of lotus japonicus, a model legume, with the aid of a large-scale cdna macroarray. experiments were carried out considering the effects of contaminating microorganisms in the soil inoculants. when the colonization by am fungi, i.e. glomus mosseae and gigaspora margarita, was well established, four cysteine protease genes were induced. in situ hybridiz ... | 2007 | 17634281 |
| fast, efficient and reproducible genetic transformation of phaseolus spp. by agrobacterium rhizogenes. | this transformation procedure generates, with high efficiency (70-90%), hairy roots in cultivars, landraces and accessions of phaseolus vulgaris (common bean) and other phaseolus spp. hairy roots rapidly develop after wounding young plantlets with agrobacterium rhizogenes, at the cotyledon node, and keeping the plants in high-humidity conditions. callogenesis always precedes hairy-root formation, and after 15 days, when roots develop at wounded sites, the stem with the normal root is cleaved bel ... | 2007 | 17641650 |
| metabolic engineering of novel ketocarotenoid production in carrot plants. | carotenoids constitute a vast group of pigments that are ubiquitous throughout nature. carrot (daucus carota l.) roots provide an important source of dietary beta-carotene (provitamin a), alpha-carotene and lutein. ketocarotenoids, such as canthaxanthin and astaxanthin, are produced by some algae and cyanobacteria but are rare in plants. ketocarotenoids are strong antioxidants that are chemically synthesized and used as dietary supplements and pigments in the aquaculture and neutraceutical indus ... | 2008 | 17682834 |
| lysm domains mediate lipochitin-oligosaccharide recognition and nfr genes extend the symbiotic host range. | legume-rhizobium symbiosis is an example of selective cell recognition controlled by host/non-host determinants. individual bacterial strains have a distinct host range enabling nodulation of a limited set of legume species and vice versa. we show here that expression of lotus japonicus nfr1 and nfr5 nod-factor receptor genes in medicago truncatula and l. filicaulis, extends their host range to include bacterial strains, mesorhizobium loti or dzl, normally infecting l. japonicus. as a result, th ... | 2007 | 17690687 |
| crown gall disease and prospects for genetic manipulation of plants. | agrobacterium tumefaciens incites crown gall tumors when bacterial dna integrates into plant nuclear dna. plant cells can express these integrated bacterial genes. following insertion of desired genes into bacterial dna using recombinant dna techniques, this system permits introduction of these new genes into plant dna. we discuss the potential for genetic manipulation of plants using agrobacterium tumefaciens and the related organism agrobacterium rhizogenes. | 1982 | 17807126 |
| ap2-erf transcription factors mediate nod factor dependent mt enod11 activation in root hairs via a novel cis-regulatory motif. | rhizobium nod factors (nfs) are specific lipochitooligosaccharides that activate host legume signaling pathways essential for initiating the nitrogen-fixing symbiotic association. this study describes the characterization of cis-regulatory elements and trans-interacting factors that regulate nf-dependent and epidermis-specific gene transcription in medicago truncatula. detailed analysis of the mt enod11 promoter using deletion, mutation, and gain-of-function constructs has led to the identificat ... | 2007 | 17827349 |
| differential expression of the tfiiia regulatory pathway in response to salt stress between medicago truncatula genotypes. | soil salinity is one of the most significant abiotic stresses for crop plants, including legumes. these plants can establish root symbioses with nitrogen-fixing soil bacteria and are able to grow in nitrogen-poor soils. medicago truncatula varieties show diverse adaptive responses to environmental conditions, such as saline soils. we have compared the differential root growth of two genotypes of m. truncatula (108-r and jemalong a17) in response to salt stress. jemalong a17 is more tolerant to s ... | 2007 | 17951460 |
| [hairy root induction and plant regeneration of rehmannia glutinosa libosch. f. hueichingensis (chao et schih) hsiao transformed by agrobacterium rhizogenes]. | an efficient system of genetic transformation and plant regeneration was established in rehmannia glutinosa libosch. f. hueichingensis (chao et schih) hsiao by infecting the segments of leaves, stems and petioles of young regenerated plantlets with agrobacterium rhizogenes strain 15834. hairy roots were produced directly from the wounded surface of the explants on hormone-free murashige and skoog (ms) medium after infection by a. rhizogenes. transformed roots grew rapidly either on solid or on l ... | 2007 | 17966459 |
| variation of 16s-23s internally transcribed spacer sequence and intervening sequence in rdna among the three major agrobacterium species. | we analyzed 16s-23s internally transcribed spacer (its) and neighboring sequences among 37 strains belonging to the three major pathogenic agrobacterium species, in order to know variation in each species and to develop a simple discrimination method. number of its size variation was 9, 4, and 7 in agrobacterium tumefaciens, agrobacterium vitis, and agrobacterium rhizogenes, respectively. the its sequence of most strains in each species was distinguishable from that of the other two species. the ... | 2009 | 17997085 |
| individual and combined effects of the rola, b, and c genes on anthraquinone production in rubia cordifolia transformed calli. | it is known that the rola, rolb, and rolc genes of agrobacterium rhizogenes t-dna affect processes of plant development and activate the synthesis of secondary metabolites in transformed plant cells. although a synergistic activity of the rol genes on root formation is well-documented, little is known about their individual and combined action on secondary metabolism. in the present investigation, we provide evidence indicating that individual rola, rolb, and rolc genes are capable of increasing ... | 2008 | 18023060 |
| [increasing the content of active constituents in polygonum cuspidatum hairy root by gene transformation technology]. | to increase the content of active constituent--re and pd of polygonum cuspidatum hairy root, through ri-mediated gene transformation technology, modified high salt low ph method was used to distill genome dna of grapevine (vitis raparia). primer was designed according to sequence of genebank (af128861). through pcr amplification obtain rs gene sequence was obtained. binary vector pcambia1300-35s-rs was constructed. frost thawing method was used to transform agrobacterium rhizogenes atcc11325. sc ... | 2007 | 18050745 |
| in vitro culture of the obligate parasite spongospora subterranea (cercozoa; plasmodiophorida) associated with root-inducing transferred-dna transformed potato hairy roots. | spongospora subterranea is a soil-borne, obligate parasitic protist that causes powdery scab of potatoes. in this study, an in vitro culture system was developed for the maintenance and proliferation of the protist in potato hairy roots. the hairy roots of potato were induced in vitro with agrobacterium rhizogenes. cystosori of s. subterranea from potato scab lesions were surface disinfested and used to inoculate potato hairy roots. plasmodia, zoosporangia, and cystosori were observed microscopi ... | 2007 | 18070323 |
| growth of hairy-root cultures in various bioreactors for the production of secondary metabolites. | agrobacterium rhizogenes-mediated hairy-root cultures are a very promising alternative to the biotechnological exploitation of plant cell cultures. their characteristic capacity for secondary-metabolite production, inherent genetic stability reflected in stable productivity and the possibility of genetic manipulation to increase biosynthetic capacity have initiated a considerable interest, both as a fundamental research tool and as a source of valuable products. one of the most important limitat ... | 2008 | 18086010 |
| 3-hydroxy-3-methylglutaryl coenzyme a reductase 1 interacts with nork and is crucial for nodulation in medicago truncatula. | nork in legumes encodes a receptor-like kinase that is required for nod factor signaling and root nodule development. using medicago truncatula nork as bait in a yeast two-hybrid assay, we identified 3-hydroxy-3-methylglutaryl coa reductase 1 (mt hmgr1) as a nork interacting partner. hmgr1 belongs to a multigene family in m. truncatula, and different hmgr isoforms are key enzymes in the mevalonate biosynthetic pathway leading to the production of a diverse array of isoprenoid compounds. testing ... | 2007 | 18156218 |
| functional characterization of palax1, a putative auxin permease, in heterologous plant systems. | we have isolated the cdna of the gene palax1 from a wild cherry tree (prunus avium). the gene and its product are highly similar in sequences to both the cdnas and the corresponding protein products of aux/lax-type genes, coding for putative auxin influx carriers. we have prepared and characterized transformed nicotiana tabacum and arabidopsis thaliana plants carrying the gene palax1. we have proved that constitutive overexpression of palax1 is accompanied by changes in the content and distribut ... | 2008 | 18184737 |
| hypericum perforatum plant cells reduce agrobacterium viability during co-cultivation. | plant recalcitrance is the major barrier in developing agrobacterium-mediated transformation protocols for several important plant species. despite the substantial knowledge of t-dna transfer process, very little is known about the factors leading to the plant recalcitrance. here, we analyzed the basis of hypericum perforatum l. (hp) recalcitrance to agrobacterium-mediated transformation using cell suspension culture. when challenged with agrobacterium, hp cells swiftly produced an intense oxida ... | 2008 | 18247048 |
| recent advances in medicago truncatula genomics. | legume rotation has allowed a consistent increase in crop yield and consequently in human population since the antiquity. legumes will also be instrumental in our ability to maintain the sustainability of our agriculture while facing the challenges of increasing food and biofuel demand. medicago truncatula and lotus japonicus have emerged during the last decade as two major model systems for legume biology. initially developed to dissect plant-microbe symbiotic interactions and especially legume ... | 2008 | 18288239 |
| recent advances in medicago truncatula genomics. | legume rotation has allowed a consistent increase in crop yield and consequently in human population since the antiquity. legumes will also be instrumental in our ability to maintain the sustainability of our agriculture while facing the challenges of increasing food and biofuel demand. medicago truncatula and lotus japonicus have emerged during the last decade as two major model systems for legume biology. initially developed to dissect plant-microbe symbiotic interactions and especially legume ... | 2008 | 18288239 |
| production of recombinant proteins in clonal root cultures using episomal expression vectors. | we have developed a fully contained system for expressing recombinant proteins that is based on clonal root cultures and episomal expression vectors. clonal root lines expressing green fluorescent protein (gfp) or human growth hormone were generated from nicotiana benthamiana leaves infected with the tobacco mosaic virus-based vector 30b after exposure to agrobacterium rhizogenes. these lines accumulated gfp at over 50 mg per kg fresh tissue, a level that is comparable with other plant productio ... | 2008 | 18306425 |
| agrobacterium rhizogenes-transformed roots of coffee (coffea arabica): conditions for long-term proliferation, and morphological and molecular characterization. | the aims of this study were to set up proliferation conditions for hairy roots of coffea arabica regenerated after transformation by agrobacterium rhizogenes strain a4-rs, and to carry out the morphological and molecular characterization of hairy root clones maintained over the long term. | 2008 | 18316320 |
| symrk defines a common genetic basis for plant root endosymbioses with arbuscular mycorrhiza fungi, rhizobia, and frankiabacteria. | root endosymbioses vitally contribute to plant nutrition and fitness worldwide. nitrogen-fixing root nodulation, confined to four plant orders, encompasses two distinct types of associations, the interaction of legumes (fabales) with rhizobia bacteria and actinorhizal symbioses, where the bacterial symbionts are actinomycetes of the genus frankia. although several genetic components of the host-symbiont interaction have been identified in legumes, the genetic basis of actinorhiza formation is un ... | 2008 | 18316735 |
| functional adaptation of a plant receptor-kinase paved the way for the evolution of intracellular root symbioses with bacteria. | nitrogen-fixing root nodule symbioses (rns) occur in two major forms-actinorhiza and legume-rhizobium symbiosis-which differ in bacterial partner, intracellular infection pattern, and morphogenesis. the phylogenetic restriction of nodulation to eurosid angiosperms indicates a common and recent evolutionary invention, but the molecular steps involved are still obscure. in legumes, at least seven genes-including the symbiosis receptor-kinase gene symrk-are essential for the interaction with rhizob ... | 2008 | 18318603 |
| programmed cell death suppression in transformed plant tissue by tomato cdnas identified from an agrobacterium rhizogenes-based functional screen. | the genetic regulation of programmed cell death (pcd) is well characterized in animal systems, but largely unresolved in plants. this research was designed to identify plant genes that can suppress pcd triggered in plants by fumonisin b1 (fb1). agrobacterium rhizogenes was used to transform individual members of a cdna library into tomato roots, which were then screened for resistance to fb1. cellular changes elicited during fb1-induced pcd include chromatin condensation, fragmentation into pycn ... | 2008 | 18324417 |
| morphometric and biochemical characterization of red beet (beta vulgaris l.) hairy roots obtained after single and double transformations. | it is known that t-dna of agrobacterium rhizogenes affects processes of plant development and activates the synthesis of secondary metabolites in transformed plant cells. in the present investigation, we provide evidence that different strains of a. rhizogenes significantly affect morphometric, morphological and functional characteristics of hairy roots of red beet (beta vulgaris l.). infection with four strains of a. rhizogenes (a4, a 2/83, a 20/83 and lmg-150) resulted in ten clones of hairy r ... | 2008 | 18327591 |
| exogenous hormones affecting morphology and biosynthetic potential of hairy root line (lyr2i) of linum album. | a hairy root line of linum album lyr2i was obtained via the genetic transformation of a cotyledon segment of the plant by cocultivating it with agrobacterium rhizogenes and culturing it in hormone-free b5 gamborg liquid medium. characteristic changes in root morphology associated with variations in biosynthetic capabilities were achieved by adding different combinations of phytohormones to the basal medium. a reversible system between hairy roots and its cultures with a diversified morphology wa ... | 2008 | 18343341 |
| characterization of an amino acid permease from the endomycorrhizal fungus glomus mosseae. | arbuscular mycorrhizal (am) fungi are capable of exploiting organic nitrogen sources, but the molecular mechanisms that control such an uptake are still unknown. polymerase chain reaction-based approaches, bioinformatic tools, and a heterologous expression system have been used to characterize a sequence coding for an amino acid permease (gmosaap1) from the am fungus glomus mosseae. the gmosaap1 shows primary and secondary structures that are similar to those of other fungal amino acid permeases ... | 2008 | 18344417 |
| root tip-dependent, active riboflavin secretion by hyoscyamus albus hairy roots under iron deficiency. | hyoscyamus albus hairy roots with/without an exogenous gene (11 clones) were established by inoculation of agrobacterium rhizogenes. all clones cultured under iron-deficient condition secreted riboflavin from the root tips into the culture medium and the productivity depended on the number and size of root tips among the clones. a decline of ph was observed before riboflavin production and root development. by studying effects of proton-pump inhibitors, medium acidification with external organic ... | 2008 | 18367404 |
| expression of tropane alkaloids in the hairy root culture of atropa acuminata substantiated by dart mass spectrometric technique. | agrobacterium rhizogenes-mediated 'hairy root' cultures were established in atropa acuminata. the chemical profiling of the hairy roots was carried out by a new mass spectrometric technique, direct analysis in real time (dart). the intact hairy roots were directly analyzed by holding them in the gap between the dart ion source and mass spectrometer. two alkaloids, atropine and scopolamine, were characterized. the structural confirmation of the two alkaloids was made through their accurate molecu ... | 2008 | 18386250 |
| bag culture: a method for root-root co-culture. | a method named "bag culture" was developed for coculturing of linum persicum (section syllinum) and l. austriacum (section linum) hairy roots. for this propose l. austriacum and l. persicum hairy root cultures were established using agrobacterium rhizogenes in mccown medium. l. persicum hairy roots in bags (1 mm2 mesh) were successfully grown together with l. austriacum hairy roots. the amounts of podophyllotoxin (ptox) and 6-methoxypodophyllotoxin (mptox) produced by l. persicum hairy root cult ... | 2008 | 18386507 |
| post-transcriptional gene silencing in the root system of the actinorhizal tree allocasuarina verticillata. | in recent years, rna interference has been exploited as a tool for investigating gene function in plants. we tested the potential of double-stranded rna interference technology for silencing a transgene in the actinorhizal tree allocasuarina verticillata. the approach was undertaken using stably transformed shoots expressing the beta-glucuronidase (gus) gene under the control of the constitutive promoter 35s; the shoots were further transformed with the agrobacterium rhizogenes a4rs containing h ... | 2008 | 18393611 |
| functions of rol genes in plant secondary metabolism. | for a long time, the agrobacterium rhizogenes rola, rolb and rolc oncogenes have been considered to be modulators of plant growth and cell differentiation. a new function of the rol genes in plant-agrobacterium interaction became apparent with the discovery that these genes are potential activators of secondary metabolism in transformed cells from the solanaceae, araliaceae, rubiaceae, vitaceae and rosaceae families. in some cases, the activator effect of individual rol genes is sufficient to ov ... | 2008 | 18434069 |
| glucomannan-mediated attachment of rhizobium leguminosarum to pea root hairs is required for competitive nodule infection. | the rhizobium leguminosarum biovar viciae genome contains several genes predicted to determine surface polysaccharides. mutants predicted to affect the initial steps of polysaccharide synthesis were identified and characterized. in addition to the known cellulose (cel) and acidic exopolysaccharide (eps) (pss) genes, we mutated three other loci; one of these loci (gmsa) determines glucomannan synthesis and one (gela) determines a gel-forming polysaccharide, but the role of the other locus (an exo ... | 2008 | 18441060 |
| the effect of chromosome geometry on genetic diversity. | although organisms with linear chromosomes must solve the problem of fully replicating their chromosome ends, this chromosome configuration has emerged repeatedly during bacterial evolution and is evident in three divergent bacterial phyla. the benefit usually ascribed to this topology is the ability to boost genetic variation through increased recombination. but because numerous processes can impact linkage disequilibrium, such an effect is difficult to assess by comparing across bacterial taxa ... | 2008 | 18493068 |
| bioactive constituent production in st. john's wort in vitro hairy roots. regenerated plant lines. | a wild strain of agrobacterium rhizogenes was used to regenerate twelve in vitro plant lines from different hairy roots of h. perforatum (st. john's wort). the production of the main bioactive constituents was observed even though their yields varied in the different plant lines. two lines were selected for the hyperoside production (4.9-4.6 mg/gdw) while nine were characterized by significant yields of chlorogenic acid (ranged from 0.47 to 1.09 mg/gdw). furthermore, one out of twelve lines show ... | 2008 | 18553917 |
| modelling in vitro growth of dense root networks. | hairy roots are plants genetically transformed by agrobacterium rhizogenes, which do not produce shoots and are composed mainly by roots. hairy roots of ophiorrhiza mungos linn. are currently gaining interest of pharmacologists, since a secondary product of their metabolism, camptothecin, is used in chemotherapy. to optimize the production of valuable secondary metabolites it is necessary to understand the metabolism and growth of these roots systems. in this work, a mathematical model for descr ... | 2008 | 18561955 |