Publications
| Title | Abstract | Year(sorted ascending) Filter | PMID Filter |
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| microtubule dynamics in root hairs of medicago truncatula. | the microtubular cytoskeleton plays an important role in the development of tip-growing plant cells, but knowledge about its dynamics is incomplete. in this study, root hairs of the legume medicago truncatula have been chosen for a detailed analysis of microtubular cytoskeleton dynamics using gfp-mbd and eb1-yfp as markers and 4d imaging. the microtubular cytoskeleton appears mainly to be composed of bundles which form tracks along which new microtubules polymerise. polymerisation rates of micro ... | 2007 | 17218039 |
| context dependence in the coevolution of plant and rhizobial mutualists. | several mechanisms are expected to rapidly rid mutualisms of genetic variation in partner quality. variation for mutualist quality, however, appears to be widespread. we used a model legume-rhizobium mutualism to test for evidence that context-dependent selection may maintain variation in partner quality. in a greenhouse experiment using 10 natural populations of medicago truncatula and two strains of sinorhizobium medicae, we detected significant genotype x genotype (g x g) interactions for pla ... | 2007 | 17535796 |
| 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 |
| influence of the poly-3-hydroxybutyrate (phb) granule-associated proteins (phap1 and phap2) on phb accumulation and symbiotic nitrogen fixation in sinorhizobium meliloti rm1021. | sinorhizobium meliloti cells store excess carbon as intracellular poly-3-hydroxybutyrate (phb) granules that assist survival under fluctuating nutritional conditions. phb granule-associated proteins (phasins) are proposed to regulate phb synthesis and granule formation. although the enzymology and genetics of phb metabolism in s. meliloti have been well characterized, phasins have not yet been described for this organism. comparison of the protein profiles of the wild type and a phb synthesis mu ... | 2007 | 17921298 |
| genetic and physical localization of an anthracnose resistance gene in medicago truncatula. | anthracnose of alfalfa, caused by the fungal pathogen colletotrichum trifolii, is one of the most destructive diseases of alfalfa worldwide. an improved understanding of the genetic and molecular mechanisms underlying host resistance will facilitate the development of resistant alfalfa cultivars, thus providing the most efficient and environmentally sound strategy to control alfalfa diseases. unfortunately, cultivated alfalfa has an intractable genetic system because of its tetrasomic inheritanc ... | 2007 | 17891371 |
| induction of a small heat shock protein and its functional roles in nicotiana plants in the defense response against ralstonia solanacearum. | in tobacco (nicotiana tabacum), ralstonia solanacearum oe1-1 (rsoe1-1) is pathogenic, whereas r. solanacearum 8107 (rs8107) is nonpathogenic and induces the hypersensitive response (hr). to elucidate the molecular mechanisms of plant-r. solanacearum interactions, we used differential display to isolate a cdna fragment, a6, regulated in tobacco by inoculation with rsoe1-1. the deduced amino acid sequence predicted from full-length a6-cdna showed similarity to small heat shock proteins from arabid ... | 2007 | 17965181 |
| different mechanisms for phytoalexin induction by pathogen and wound signals in medicago truncatula. | cell suspensions of the model legume medicago truncatula accumulated the isoflavonoid phytoalexin medicarpin in response to yeast elicitor or methyl jasmonate (mj), accompanied by decreased levels of isoflavone glycosides in mj-treated cells. dna microarray analysis revealed rapid, massive induction of early (iso)flavonoid pathway gene transcripts in response to yeast elicitor, but not mj, and differential induction by the two elicitors of sets of genes encoding transcription factors, abc transp ... | 2007 | 17971436 |
| subcellular localisation of medicago truncatula 9/13-hydroperoxide lyase reveals a new localisation pattern and activation mechanism for cyp74c enzymes. | hydroperoxide lyase (hpl) is a key enzyme in plant oxylipin metabolism that catalyses the cleavage of polyunsaturated fatty acid hydroperoxides produced by the action of lipoxygenase (lox) to volatile aldehydes and oxo acids. the synthesis of these volatile aldehydes is rapidly induced in plant tissues upon mechanical wounding and insect or pathogen attack. together with their direct defence role towards different pathogens, these compounds are believed to play an important role in signalling wi ... | 2007 | 17983471 |
| 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 |
| identification of new potential regulators of the medicago truncatula-sinorhizobium meliloti symbiosis using a large-scale suppression subtractive hybridization approach. | we set up a large-scale suppression subtractive hybridization (ssh) approach to identify medicago truncatula genes differentially expressed at different stages of the symbiotic interaction with sinorhizobium meliloti, with a particular interest for regulatory genes. we constructed 7 ssh libraries covering successive stages from nod factor signal transduction to s. meliloti infection, nodule organogenesis, and functioning. over 26,000 clones were differentially screened by two rounds of macroarra ... | 2007 | 17378435 |
| recovery of nicotiana benthamiana plants from a necrotic response induced by a nepovirus is associated with rna silencing but not with reduced virus titer. | recovery of plants from virus-induced symptoms is often described as a consequence of rna silencing, an antiviral defense mechanism. for example, recovery of nicotiana clevelandii from a nepovirus (tomato black ring virus) is associated with a decreased viral rna concentration and sequence-specific resistance to further virus infection. in this study, we have characterized the interaction of another nepovirus, tomato ringspot virus (torsv), with host defense responses during symptom induction an ... | 2007 | 17728227 |
| salt-tolerant rhizobia isolated from a tunisian oasis that are highly effective for symbiotic n2-fixation with phaseolus vulgaris constitute a novel biovar (bv. mediterranense) of sinorhizobium meliloti. | nodulation of common bean was explored in six oases in the south of tunisia. nineteen isolates were characterized by pcr-rflp of 16s rdna. three species of rhizobia were identified, rhizobium etli, rhizobium gallicum and sinorhizobium meliloti. the diversity of the symbiotic genes was then assessed by pcr-rflp of nodc and nifh genes. the majority of the symbiotic genotypes were conserved between oases and other soils of the north of the country. sinorhizobia isolated from bean were then compared ... | 2007 | 17019605 |
| development of bioinformatic tools to support est-sequencing, in silico- and microarray-based transcriptome profiling in mycorrhizal symbioses. | the great majority of terrestrial plants enters a beneficial arbuscular mycorrhiza (am) or ectomycorrhiza (ecm) symbiosis with soil fungi. in the spp 1084 "molmyk: molecular basics of mycorrhizal symbioses", high-throughput est-sequencing was performed to obtain snapshots of the plant and fungal transcriptome in mycorrhizal roots and in extraradical hyphae. to focus activities, the interactions between medicago truncatula and glomus intraradices as well as populus tremula and amanita muscaria we ... | 2007 | 17081576 |
| gene expression analysis of arbuscule development and functioning. | the arbuscular mycorrhiza (am) is characterized by specific morphological structures of the fungus and the plant and by physiological adaptations which are mostly beneficial for both partners of the symbiosis. this review describes approaches to study the molecular basis of the interaction. rna accumulation patterns have been monitored in pisum sativum to analyse the plant response to arbuscule development. in a direct approach, the mtha1 gene from medicago truncatula was cloned which is express ... | 2007 | 17081578 |
| 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 |
| a udp-glucose:isoflavone 7-o-glucosyltransferase from the roots of soybean (glycine max) seedlings. purification, gene cloning, phylogenetics, and an implication for an alternative strategy of enzyme catalysis. | isoflavones, a class of flavonoids, play very important roles in plant-microbe interactions in certain legumes such as soybeans (glycine max l. merr.). g. max udp-glucose:isoflavone 7-o-glucosyltransferase (gmif7gt) is a key enzyme in the synthesis of isoflavone conjugates, which accumulate in large amounts in vacuoles and serve as an isoflavonoid pool that allows for interaction with microorganisms. in this study, the 14,000-fold purification of gmif7gt from the roots of g. max seedlings was ac ... | 2007 | 17565994 |
| roles of poly-3-hydroxybutyrate (phb) and glycogen in symbiosis of sinorhizobium meliloti with medicago sp. | poly-3-hydroxybutyrate (phb) and glycogen are major carbon storage compounds in sinorhizobium meliloti. the roles of phb and glycogen in rhizobia-legume symbiosis are not fully understood. glycogen synthase mutations were constructed by in-frame deletion (glga1) or insertion (glga2). these mutations were combined with a phbc mutation to make all combinations of double and triple mutants. phb was not detectable in any of the mutants containing the phbc mutation; glycogen was not detectable in any ... | 2007 | 17259610 |
| abscisic acid rescues the root meristem defects of the medicago truncatula latd mutant. | the latd gene of the model legume, medicago truncatula, is required for the normal function of three meristems, i.e. the primary root, lateral roots and nitrogen-fixing nodules. in latd mutants, primary root growth eventually arrests, resulting in a disorganized root tip lacking a presumptive meristem and root cap columella cells. lateral root organs are more severely affected; latd lateral roots and nodules arrest immediately after emerging from the primary root, and reveal a lack of organizati ... | 2007 | 17239844 |
| 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 |
| the lipopolysaccharide of sinorhizobium meliloti suppresses defense-associated gene expression in cell cultures of the host plant medicago truncatula. | in the establishment of symbiosis between medicago truncatula and the nitrogen-fixing bacterium sinorhizobium meliloti, the lipopolysaccharide (lps) of the microsymbiont plays an important role as a signal molecule. it has been shown in cell cultures that the lps is able to suppress an elicitor-induced oxidative burst. to investigate the effect of s. meliloti lps on defense-associated gene expression, a microarray experiment was performed. for evaluation of the m. truncatula microarray datasets, ... | 2007 | 17220366 |
| 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 |
| mastoparan activates calcium spiking analogous to nod factor-induced responses in medicago truncatula root hair cells. | the rhizobial-derived signaling molecule nod factor is essential for the establishment of the medicago truncatula/sinorhizobium meliloti symbiosis. nod factor perception and signal transduction in the plant involve calcium spiking and lead to the induction of nodulation gene expression. it has previously been shown that the heterotrimeric g-protein agonist mastoparan can activate nodulation gene expression in a manner analogous to nod factor activation of these genes and this requires doesn't ma ... | 2007 | 17322338 |
| 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 |
| 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 |
| characterization of the interaction between the bacterial wilt pathogen ralstonia solanacearum and the model legume plant medicago truncatula. | the soilborne pathogen ralstonia solanacearum is the causal agent of bacterial wilt and attacks more than 200 plant species, including some legumes and the model legume plant medicago truncatula. we have demonstrated that m. truncatula accessions jemalong a17 and f83005.5 are susceptible to r. solanacearum and, by screening 28 r. solanacearum strains on the two m. truncatula lines, differential interactions were identified. r. solanacearum gmi1000 infected jemalong a17 line, and disease symptoms ... | 2007 | 17313167 |
| identification of qtl for reaction to three races of colletotrichum trifolii and further analysis of inheritance of resistance in autotetraploid lucerne. | anthracnose, caused by colletotrichum trifolii, is one of the most serious diseases of lucerne worldwide. the disease is managed through deployment of resistant cultivars, but new pathotypes present a challenge to the successful implementation of this strategy. this paper reports the genetic map locations of quantitative trait loci (qtl) for reaction to races 1, 2 and 4 of c. trifolii in a single autotetraploid lucerne clone, designated w126 from the australian cv. trifecta. resistance was mappe ... | 2007 | 17356866 |
| tracembler--software for in-silico chromosome walking in unassembled genomes. | whole genome shotgun sequencing produces increasingly higher coverage of a genome with random sequence reads. progressive whole genome assembly and eventual finishing sequencing is a process that typically takes several years for large eukaryotic genomes. in the interim, all sequence reads of public sequencing projects are made available in repositories such as the ncbi trace archive. for a particular locus, sequencing coverage may be high enough early on to produce a reliable local genome assem ... | 2007 | 17490482 |
| arbuscular mycorrhizal symbiosis is accompanied by local and systemic alterations in gene expression and an increase in disease resistance in the shoots. | in natural ecosystems, the roots of many plants exist in association with arbuscular mycorrhizal (am) fungi, and the resulting symbiosis has profound effects on the plant. the most frequently documented response is an increase in phosphorus nutrition; however, other effects have been noted, including increased resistance to abiotic and biotic stresses. here we used a 16,000-feature oligonucleotide array and real-time quantitative rt-pcr to explore transcriptional changes triggered in medicago tr ... | 2007 | 17419842 |
| increased calcium bioavailability in mice fed genetically engineered plants lacking calcium oxalate. | bioavailable calcium affects bone formation and calcification. here we investigate how a single gene mutation altering calcium partitioning in the model forage crop medicago truncatula affects calcium bioavailability. previously, the cod5 m. truncatula mutant was identified which contains identical calcium concentrations to wild-type, but contains no oxalate crystals. in this study, equal number of male and female mice were randomly grouped and then fed one of four 45ca-containing diets: m. trun ... | 2007 | 17514431 |
| medicago truncatula root nodule proteome analysis reveals differential plant and bacteroid responses to drought stress. | drought is one of the environmental factors most affecting crop production. under drought, symbiotic nitrogen fixation is one of the physiological processes to first show stress responses in nodulated legumes. this inhibition process involves a number of factors whose interactions are not yet understood. this work aims to further understand changes occurring in nodules under drought stress from a proteomic perspective. drought was imposed on medicago truncatula 'jemalong a17' plants grown in sym ... | 2007 | 17545507 |
| comparison of rhizobia that nodulate medicago laciniata and medicago truncatula present in a single tunisian arid soil. | the rhizobia present in a single arid region tunisian soil that nodulate medicago laciniata and medicago truncatula were compared. all isolates, 40 from each host, were sinorhizobium meliloti based on 16s rrna polymerase chain reaction restriction fragment length polymorphism (pcr-rflp) patterns and subsequent confirmation by sequence analysis of the 16s rrna genes in four representatives from each host species. there was no apparent relationship between medicago host species of isolation and th ... | 2007 | 17496977 |
| root hair curling and rhizobium infection in medicago truncatula are mediated by phosphatidylinositide-regulated endocytosis and reactive oxygen species. | the symbiotic relationships between legumes and rhizobacteria involve extensive signalling between the two organisms. studies using genetic, biochemical, and pharmacological approaches have demonstrated the involvement of calcium and reactive oxygen species in the establishment of symbiotic interactions. in the early stage of the interactions rhizobia grow as infection thread within host root hairs and are internalized into the plant cells via endocytosis. it is shown here that inoculation of me ... | 2007 | 17420174 |
| 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 |
| medicago truncatula as a model for nonhost resistance in legume-parasitic plant interactions. | crenate broomrape (orobanche crenata) is a root parasitic weed that represents a major constraint for grain legume production in mediterranean and west asian countries. medicago truncatula has emerged as an important model plant species for structural and functional genomics. the close phylogenic relationship of m. truncatula with crop legumes increases its value as a resource for understanding resistance against orobanche spp. different cytological methods were used to study the mechanisms of r ... | 2007 | 17693539 |
| horizontal gene transfer and homologous recombination drive the evolution of the nitrogen-fixing symbionts of medicago species. | using nitrogen-fixing sinorhizobium species that interact with medicago plants as a model system, we aimed at clarifying how sex has shaped the diversity of bacteria associated with the genus medicago on the interspecific and intraspecific scales. to gain insights into the diversification of these symbionts, we inferred a topology that includes the different specificity groups which interact with medicago species, based on sequences of the nodulation gene cluster. furthermore, 126 bacterial isol ... | 2007 | 17496100 |
| effects of aiia-mediated quorum quenching in sinorhizobium meliloti on quorum-sensing signals, proteome patterns, and symbiotic interactions. | many behaviors in bacteria, including behaviors important to pathogenic and symbiotic interactions with eukaryotic hosts, are regulated by a mechanism called quorum sensing (qs). a "quorum-quenching" approach was used here to identify qs-regulated behaviors in the n-fixing bacterial symbiont sinorhizobium meliloti. the aiia lactonase from bacillus produced in s. meliloti was shown to enzymatically inactivate s. meliloti's n-acyl homoserine lactone (ahl) qs signals, thereby disrupting normal qs r ... | 2007 | 17601171 |
| crystal structure of medicago truncatula ugt85h2--insights into the structural basis of a multifunctional (iso)flavonoid glycosyltransferase. | (iso)flavonoids are a diverse group of plant secondary metabolites with important effects on plant, animal and human health. they exist in various glycosidic forms. glycosylation, which may determine their bioactivities and functions, is controlled by specific plant uridine diphosphate glycosyltransferases (ugts). we describe a new multifunctional (iso)flavonoid glycosyltransferase, ugt85h2, from the model legume medicago truncatula with activity towards a number of phenylpropanoid-derived natur ... | 2007 | 17553523 |
| 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 |
| 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 |
| promex: a mass spectral reference database for proteins and protein phosphorylation sites. | in the last decade, techniques were established for the large scale genome-wide analysis of proteins, rna, and metabolites, and database solutions have been developed to manage the generated data sets. the golm metabolome database for metabolite data (gmd) represents one such effort to make these data broadly available and to interconnect the different molecular levels of a biological system 1. as data interpretation in the light of already existing data becomes increasingly important, these ini ... | 2007 | 17587460 |
| how rhizobial symbionts invade plants: the sinorhizobium-medicago model. | nitrogen-fixing rhizobial bacteria and leguminous plants have evolved complex signal exchange mechanisms that allow a specific bacterial species to induce its host plant to form invasion structures through which the bacteria can enter the plant root. once the bacteria have been endocytosed within a host-membrane-bound compartment by root cells, the bacteria differentiate into a new form that can convert atmospheric nitrogen into ammonia. bacterial differentiation and nitrogen fixation are depend ... | 2007 | 17632573 |
| 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 |
| towards the elucidation of am-specific transcription in medicago truncatula. | roots of most plants form a mutualistic interaction with arbuscular mycorrhiza (am) fungi. during the symbiosis, drastic morphological and physiological changes occur in the host plant root system. these changes are likely to be controlled by a specific genetic program of the plant. the legume medicago truncatula is a model system widely used to elucidate this program. a number of loci required for am-development have been identified by the analysis of m. truncatula mutants; however, the genes i ... | 2007 | 17141285 |
| a transient decrease in reactive oxygen species in roots leads to root hair deformation in the legume-rhizobia symbiosis. | * a possible role for reactive oxygen species (ros) in root hair deformation in response to nod factor (nf) was investigated using medicago truncatula nodulation mutants, and an inhibitor and precursors of ros. * in wild-type roots, ros efflux transiently decreased approximately 1 h after nf treatment. transcript accumulation of two nadph oxidase homologs, respiratory burst oxidase homolog 2 (mtrboh2) and mtrboh3, also transiently decreased at 1 h. however, in the nonnodulating mutant nod factor ... | 2007 | 17176392 |
| genetic variation and pathogenicity of anastomosis group 2 isolates of rhizoctonia solani in australia. | a collection of isolates of rhizoctonia solani anastomosis group (ag) 2 was examined for genetic diversity and pathogenicity. anastomosis reactions classified the majority of isolates into the known subgroups of ag 2-1 and ag 2-2 but the classification of several isolates was ambiguous. morphological characters were consistent with the species, with no discriminating characters existing between subgroups. vertical page of pectic enzymes enabled the separation of zymogram group (zg) 5 and 6 withi ... | 2007 | 17707626 |
| molecular cloning of a bifunctional beta-xylosidase/alpha-l-arabinosidase from alfalfa roots: heterologous expression in medicago truncatula and substrate specificity of the purified enzyme. | glycoside hydrolases are often members of a multigene family, suggesting individual roles for each isoenzyme. various extracellular glycoside hydrolases have an important but poorly understood function in remodelling the cell wall during plant growth. here, msxyl1, a concanavalin a-binding protein from alfalfa (medicago sativa l.) belonging to the glycoside hydrolase family 3 (beta-d-xylosidase branch) is characterized. transcripts of msxyl1 were detected in roots (particularly root tips), root ... | 2007 | 17615411 |
| medicago truncatula syntaxin syp132 defines the symbiosome membrane and infection droplet membrane in root nodules. | symbiotic association of legume plants with rhizobia bacteria culminates in organogenesis of nitrogen-fixing root nodules. in indeterminate nodules, plant cells accommodate rhizobial infection by enclosing each bacterium in a membrane-bound, organelle-like compartment called the symbiosome. numerous symbiosomes occupy each nodule cell; therefore an enormous amount of membrane material must be delivered to the symbiosome membrane for its development and maintenance. protein delivery to the symbio ... | 2007 | 16944200 |
| validation of in silico-predicted genic snps in white clover (trifolium repens l.), an outbreeding allopolyploid species. | white clover (trifolium repens l.) is an obligate outbreeding allotetraploid forage legume. gene-associated snps provide the optimum genetic system for improvement of such crop species. an est resource obtained from multiple cdna libraries constructed from numerous genotypes of a single cultivar has been used for in silico snp discovery and validation. a total of 58 from 236 selected sequence clusters (24.5%) were fully validated as containing polymorphic snps by genotypic analysis across the pa ... | 2007 | 17216492 |
| construction of genetic linkage map of the medicinal and ornamental plant catharanthus roseus. | an integrated genetic linkage map of the medicinal and ornamental plant catharanthus roseus, based on different types of molecular and morphological markers was constructed, using a f(2) population of 144 plants. the map defines 14 linkage groups (lgs) and consists of 131 marker loci, including 125 molecular dna markers (76 rapd, 3 rapd combinations; 7 issr; 2 est-ssr from medicago truncatula and 37 other pcr based dna markers), selected from a total of 472 primers or primer pairs, and six morph ... | 2007 | 18305345 |
| tandem duplications of a degenerated gtp-binding domain at the origin of gtpase receptors toc159 and thylakoidal srp. | the evolutionary origin of some nuclear encoded proteins that translocate proteins across the chloroplast envelope remains unknown. therefore, sequences of gtpase proteins constituting the arabidopsis thaliana translocon at the outer membrane of chloroplast (attoc) complexes were analyzed by means of hca. in particular, attoc159 and related proteins (attoc132, attoc120, and attoc90) do not have proven homologues of prokaryotic or eukaryotic ancestry. we established that the three domains commonl ... | 2007 | 17950698 |
| computer-vision analysis of seedling responses to light and gravity. | measuring the effects of mutation, natural variation or treatment on the development of plant form is often complicated by the shapes, dynamics or small size of the organismal structures under study. this limits accuracy and throughput of measurement and thereby limits progress toward understanding the underlying gene networks and signaling systems. a computer-vision platform based on electronic image capture and shape-analysis algorithms was developed as an alternative to the mostly manual meth ... | 2007 | 17711415 |
| cgkb: an annotation knowledge base for cowpea (vigna unguiculata l.) methylation filtered genomic genespace sequences. | cowpea [vigna unguiculata (l.) walp.] is one of the most important food and forage legumes in the semi-arid tropics because of its ability to tolerate drought and grow on poor soils. it is cultivated mostly by poor farmers in developing countries, with 80% of production taking place in the dry savannah of tropical west and central africa. cowpea is largely an underexploited crop with relatively little genomic information available for use in applied plant breeding. the goal of the cowpea genomic ... | 2007 | 17445272 |
| riboregulators in plant development. | npcrna (non-protein-coding rnas) are an emerging class of regulators, so-called riboregulators, and include a large diversity of small rnas [mirnas (micrornas)/sirnas (small interfering rnas)] that are involved in various developmental processes in plants and animals. in addition, several other npcrnas encompassing various transcript sizes (up to several kilobases) have been identified using different genomic approaches. much less is known about the mechanism of action of these other classes of ... | 2007 | 18031282 |
| genebins: a database for classifying gene expression data, with application to plant genome arrays. | to interpret microarray experiments, several ontological analysis tools have been developed. however, current tools are limited to specific organisms. | 2007 | 17349060 |
| genome mapping of white clover (trifolium repens l.) and comparative analysis within the trifolieae using cross-species ssr markers. | allotetraploid white clover (trifolium repens l.), a cool-season perennial legume used extensively as forage for livestock, is an important target for marker-assisted breeding. a genetic linkage map of white clover was constructed using simple sequence repeat (ssr) markers based on sequences from several trifolieae species, including white clover, red clover (t. pratense l.), medicago truncatula (gaertn.) and soybean (glycine max l.). an f(1) population consisting of 179 individuals, from a cros ... | 2007 | 17356868 |
| a novel family of lectins evolutionarily related to class v chitinases: an example of neofunctionalization in legumes. | a lectin has been identified in black locust (robinia pseudoacacia) bark that shares approximately 50% sequence identity with plant class v chitinases but is essentially devoid of chitinase activity. specificity studies indicated that the black locust chitinase-related agglutinin (robpscra) preferentially binds to high-mannose n-glycans comprising the proximal pentasaccharide core structure. closely related orthologs of robpscra could be identified in the legumes glycine max, medicago truncatula ... | 2007 | 17098856 |
| leveraging model legume information to find candidate genes for soybean sudden death syndrome using the legume information system. | comparative genomics is an emerging and powerful approach to achieve crop improvement. using comparative genomics, information from model plant species can accelerate the discovery of genes responsible for disease and pest resistance, tolerance to plant stresses such as drought, and enhanced nutritional value including production of anti-oxidants and anti-cancer compounds. we demonstrate here how to use the legume information system for a comparative genomics study, leveraging genomic informatio ... | 2007 | 18287696 |
| genomic organization and evolutionary insights on grp and ncr genes, two large nodule-specific gene families in medicago truncatula. | deciphering the mechanisms leading to symbiotic nitrogen-fixing root nodule organogenesis in legumes resulted in the identification of numerous nodule-specific genes and gene families. among them, ncr and grp genes encode short secreted peptides with potential antimicrobial activity. these genes appear to form large multigenic families in medicago truncatula and other closely related legume species, whereas no similar genes were found in databases of lotus japonicus and glycine max. we analyzed ... | 2007 | 17849716 |
| the agc kinase mtire: a link to phospholipid signaling during nodulation? | the development of nitrogen fixing root nodules is complex and involves an interplay of signaling processes. during maturation of plant host cells and their endocytosed rhizobia in symbiosomes, host cells and symbiosomes expand. this expansion is accompanied by a large quantity of membrane biogenesis. we recently characterized an agc kinase gene, mtire, that could play a role in this expansion. mtire's expression coincides with host cell and symbiosome expansion in the proximal side of the invas ... | 2007 | 19704633 |
| nodulation studies in the model legume medicago truncatula: advantages of using the constitutive ef1alpha promoter and limitations in detecting fluorescent reporter proteins in nodule tissues. | the cauliflower mosaic virus 35s promoter currently is being used in rnai-based approaches for attenuating host gene expression during legume root nodule development and also for the expression of fluorescent reporters in nodule tissues. in this study, we have evaluated the expression of this promoter in the indeterminate nodules of the model plant medicago truncatula. our results clearly show that the 35s promoter is inactive in both the nodule meristem and in bacteroid-containing cells of the ... | 2007 | 17849706 |
| a functional genomics approach to (iso)flavonoid glycosylation in the model legume medicago truncatula. | analysis of over 200,000 expressed sequence tags from a range of medicago truncatula cdna libraries resulted in the identification of over 150 different family 1 glycosyltransferase (ugt) genes. of these, 63 were represented by full length clones in an est library collection. among these, 19 gave soluble proteins when expressed in e. coli, and these were screened for catalytic activity against a range of flavonoid and isoflavonoid substrates using a high-throughput hplc assay method. eight ugts ... | 2007 | 17437063 |
| repetitive dna in the pea (pisum sativum l.) genome: comprehensive characterization using 454 sequencing and comparison to soybean and medicago truncatula. | extraordinary size variation of higher plant nuclear genomes is in large part caused by differences in accumulation of repetitive dna. this makes repetitive dna of great interest for studying the molecular mechanisms shaping architecture and function of complex plant genomes. however, due to methodological constraints of conventional cloning and sequencing, a global description of repeat composition is available for only a very limited number of higher plants. in order to provide further data re ... | 2007 | 18031571 |
| ancordin, the major rhizome protein of madeira-vine, with trypsin inhibitory and stimulatory activities in nitric oxide productions. | anredera cordifolia (ten.) steenis, or the synonymous name of boussingaultia baselloides or boussingaultia gracilis var. pseudobaselloides, is a south american species of ornamental succulent vine, commonly known as the madeira-vine. the fresh leaves of madeira-vine are frequently used as vegetables. a. cordifolia is an evergreen climber that grows from fleshy rhizomes. the rhizome contained one major (23kda) protein band under non-reducing condition in the sds-page. the first 15 amino acids in ... | 2007 | 17499881 |
| characterization of resistance to multiple aphid species (hemiptera: aphididae) in medicago truncatula. | aphids are phloem-feeding insects that damage many important crops throughout the world yet, compared to plant-pathogen interactions, little is known about the mechanisms by which plants become resistant to aphids. medicago truncatula (barrel medic) is widely considered as the pre-eminent model legume for genetic and biological research and in australia is an important pasture species. six cultivars of m. truncatula with varying levels of resistance to two pests of pasture and forage legumes, th ... | 2007 | 17298680 |
| involvement of the octadecanoid pathway in bluegreen aphid resistance in medicago truncatula. | aphids are major insect pests of plants that feed directly from the phloem. we used the model legume medicago truncatula gaert. (barrel medic) to elucidate host resistance to aphids and identified a single dominant gene which confers resistance to acyrthosiphon kondoi shinji (bluegreen aphid). to understand how this gene conditions resistance to bluegreen aphid, transcription profiling of 23 defense-related genes representing various signaling pathways was undertaken using a pair of near-isogeni ... | 2007 | 17249425 |
| independent action and contrasting phenotypes of resistance genes against spotted alfalfa aphid and bluegreen aphid in medicago truncatula. | host resistance to aphids is poorly understood. medicago truncatula, a model legume and cultivated pasture species, was used to elucidate defense against two aphid species, therioaphis trifolii f. maculata (spotted alfalfa aphid, saa) and acyrthosiphon kondoi (bluegreen aphid, bga). aphid performance and plant damage were compared between near-isogenic cultivars, mogul and borung, that differ in resistance to both aphids. analyses of aphid resistance in mogul x borung f2 plants and their progeny ... | 2007 | 17244058 |
| characterization of pea aphid resistance in medicago truncatula. | to achieve a thorough understanding of plant-aphid interactions, it is necessary to investigate in detail both the plant and insect side of the interaction. the pea aphid (pa; acyrthosiphon pisum) has been selected by an international consortium as the model species for genetics and genomics studies, and the model legume medicago truncatula is a host of this aphid. in this study, we identified resistance to pa in a m. truncatula line, 'jester', with well-characterized resistance to a closely rel ... | 2008 | 18184733 |
| are there benefits of simultaneous root colonization by different arbuscular mycorrhizal fungi? | arbuscular mycorrhizal fungal (amf) communities were established in pots using fungal isolates from a single field in switzerland. it was tested whether multispecies mixtures provided more phosphorus and supported greater plant growth than single amf species. two host plants, medic (medicago truncatula) and leek (allium porrum), were inoculated with three amf species (glomus mosseae, g. claroideum and g. intraradices), either separately or in mixtures. the composition of the amf communities in t ... | 2008 | 18042204 |
| identification of transcription factors involved in root apex responses to salt stress in medicago truncatula. | the root apex contains meristematic cells that determine root growth and architecture in the soil. specific transcription factor (tf) genes in this region may integrate endogenous signals and external cues to achieve this. early changes in transcriptional responses involving tf genes after a salt stress in medicago truncatula (mt) roots were analysed using two complementary transcriptomic approaches. forty-six salt-regulated tf genes were identified using massive quantitative real-time rt-pcr tf ... | 2008 | 18987888 |
| genome-wide transcriptional analysis of super-embryogenic medicago truncatula explant cultures. | the medicago truncatula (m. truncatula) line 2ha has a 500-fold greater capacity to regenerate plants in culture by somatic embryogenesis than its wild type progenitor jemalong. to understand the molecular basis for the regeneration capacity of this super-embryogenic line 2ha, using affymetrix genechip(r), we have compared transcriptomes of explant leaf cultures of these two lines that were grown on media containing the auxin naa (1-naphthaleneacetic acid) and the cytokinin bap (6-benzylaminopur ... | 2008 | 18950541 |
| a community resource for high-throughput quantitative rt-pcr analysis of transcription factor gene expression in medicago truncatula. | medicago truncatula is a model legume species that is currently the focus of an international genome sequencing effort. although several different oligonucleotide and cdna arrays have been produced for genome-wide transcript analysis of this species, intrinsic limitations in the sensitivity of hybridization-based technologies mean that transcripts of genes expressed at low-levels cannot be measured accurately with these tools. amongst such genes are many encoding transcription factors (tfs), whi ... | 2008 | 18611268 |
| trans-regulation of the expression of the transcription factor mthap2-1 by a uorf controls root nodule development. | mthap2-1 is a ccaat-binding transcription factor from the model legume medicago truncatula. we previously showed that mthap2-1 expression is regulated both spatially and temporally by microrna169. here we present a novel regulatory mechanism controlling mthap2-1 expression. alternative splicing of an intron in the mthap2-1 5'leader sequence (ls) becomes predominant during the development of root nodules, leading to the production of a small peptide, uorf1p. our results indicate that binding of u ... | 2008 | 18519645 |
| responses of the model legume medicago truncatula to the rhizobial exopolysaccharide succinoglycan. | many species of rhizobial bacteria can invade their plant hosts and induce development of symbiotic nitrogen-fixing nodules only if they are able to produce an acidic exopolysaccharide (eps) with certain structural and molecular weight characteristics.1-3sinorhizobium meliloti that produces the functional form of the exopolysaccharide succinoglycan induces formation of invasion structures called infection threads in the root hair cells of its plant hosts alfalfa and medicago truncatula. however, ... | 2008 | 19704531 |
| metabolic and genetic perturbations accompany the modification of galactomannan in seeds of medicago truncatula expressing mannan synthase from guar (cyamopsis tetragonoloba l.). | galactomannan gums are widely used in the food and oil industries, and there is considerable interest in applying biotechnological approaches to improve their physical properties. a mannan synthase from guar (cyamopsis tetragonoloba) was expressed under the control of a bean beta-phaseolin promoter in transgenic medicago truncatula. although the expression of exogenous mannan synthase caused a slight decrease in galactomannan levels in medicago, the molecular weight and viscosity of the polymer ... | 2008 | 18433421 |
| exploring the nuclear proteome of medicago truncatula at the switch towards seed filling. | despite its importance in determining seed composition, and hence quality, regulation of the development of legume seeds is incompletely understood. because of the cardinal role played by the nucleus in gene expression and regulation, we have characterized the nuclear proteome of medicago truncatula at the 12 days after pollination (dap) stage that marks the switch towards seed filling. nano-liquid chromatography-tandem mass spectrometry analysis of nuclear protein bands excised from one-dimensi ... | 2008 | 18643982 |
| the lipoxygenase gene family: a genomic fossil of shared polyploidy between glycine max and medicago truncatula. | soybean lipoxygenases (lxs) play important roles in plant resistance and in conferring the distinct bean flavor. lxs comprise a multi-gene family that includes gmlx1, gmlx2 and gmlx3, and many of these genes have been characterized. we were interested in investigating the relationship between the soybean lipoxygenase isozymes from an evolutionary perspective, since soybean has undergone two rounds of polyploidy. here we report the tetrad genome structure of soybean lx regions produced by ancient ... | 2008 | 19105811 |
| analysis of genome organization, composition and microsynteny using 500 kb bac sequences in chickpea. | the small genome size (740 mb), short life cycle (3 months) and high economic importance as a food crop legume make chickpea (cicer arietinum l.) an important system for genomics research. although several genetic linkage maps using various markers and genomic tools have become available, sequencing efforts and their use are limited in chickpea genomic research. in this study, we explored the genome organization of chickpea by sequencing approximately 500 kb from 11 bac clones (three representin ... | 2008 | 18504542 |
| fractionation of synteny in a genomic region containing tandemly duplicated genes across glycine max, medicago truncatula, and arabidopsis thaliana. | extended comparison of gene sequences found on homeologous soybean bacterial artificial chromosomes to medicago truncatula and arabidopsis thaliana genomic sequences demonstrated a network of synteny within conserved regions interrupted by gene addition and/or deletions. consolidation of gene order among all 3 species provides a picture of ancestral gene order. the observation supports a genome history of fractionation resulting from gene loss/addition and rearrangement. in all 3 species, cluste ... | 2008 | 18316321 |
| construction of a rice glycosyltransferase phylogenomic database and identification of rice-diverged glycosyltransferases. | glycosyltransferases (gts; ec 2.4.x.y) constitute a large group of enzymes that form glycosidic bonds through transfer of sugars from activated donor molecules to acceptor molecules. gts are critical to the biosynthesis of plant cell walls, among other diverse functions. based on the carbohydrate-active enzymes (cazy) database and sequence similarity searches, we have identified 609 potential gt genes (loci) corresponding to 769 transcripts (gene models) in rice (oryza sativa), the reference mon ... | 2008 | 19825588 |
| gfp tagging of sieve element occlusion (seo) proteins results in green fluorescent forisomes. | forisomes are ca(2+)-driven, atp-independent contractile protein bodies that reversibly occlude sieve elements in faboid legumes. they apparently consist of at least three proteins; potential candidates have been described previously as 'for' proteins. we isolated three genes from medicago truncatula that correspond to the putative forisome proteins and expressed their green fluorescent protein (gfp) fusion products in vicia faba and glycine max using the composite plant methodology. in both spe ... | 2008 | 18784195 |
| identification and characterization of nucleotide-binding site-leucine-rich repeat genes in the model plant medicago truncatula. | the nucleotide-binding site (nbs)-leucine-rich repeat (lrr) gene family accounts for the largest number of known disease resistance genes, and is one of the largest gene families in plant genomes. we have identified 333 nonredundant nbs-lrrs in the current medicago truncatula draft genome (mt1.0), likely representing 400 to 500 nbs-lrrs in the full genome, or roughly 3 times the number present in arabidopsis (arabidopsis thaliana). although many characteristics of the gene family are similar to ... | 2008 | 17981990 |
| heterologous expression of iap1, a seed protein from bean modified by indole-3-acetic acid, in arabidopsis thaliana and medicago truncatula. | the seed protein iap1 from bean (pviap1; phaseolus vulgaris l.) that is modified by the phytohormone indole-3-acetic acid (iaa) was heterologously expressed in the two reference plant species arabidopsis thaliana and medicago truncatula. for the transformation of medicago we devised a novel protocol using seedling infiltration. when pviap1 was overexpressed under the control of the constitutive 35scamv promoter in arabidopsis, the plants showed signs of earlier bolting and enhanced branching. ex ... | 2008 | 18097685 |
| root exudates regulate soil fungal community composition and diversity. | plants are in constant contact with a community of soil biota that contains fungi ranging from pathogenic to symbiotic. a few studies have demonstrated a critical role of chemical communication in establishing highly specialized relationships, but the general role for root exudates in structuring the soil fungal community is poorly described. this study demonstrates that two model plant species (arabidopsis thaliana and medicago truncatula) are able to maintain resident soil fungal populations b ... | 2008 | 18083870 |
| planttribes: a gene and gene family resource for comparative genomics in plants. | the planttribes database (http://fgp.huck.psu.edu/tribe.html) is a plant gene family database based on the inferred proteomes of five sequenced plant species: arabidopsis thaliana, carica papaya, medicago truncatula, oryza sativa and populus trichocarpa. we used the graph-based clustering algorithm mcl [van dongen (technical report ins-r0010 2000) and enright et al. (nucleic acids res. 2002; 30: 1575-1584)] to classify all of these species' protein-coding genes into putative gene families, calle ... | 2008 | 18073194 |
| transcriptional regulation and signaling in phosphorus starvation: what about legumes? | the availability of soil phosphorus (p), an essential element, is one of the most important requirements for plant growth and crop production. the morphological and physiological adaptations evolved by plants to cope with p starvation have been well characterized. several p deficiency plant responses are regulated at the transcriptional level. microarray analysis has generated valuable information on global gene expression in arabidopsis thaliana grown under p-stress. despite the identification ... | 2008 | 19017108 |
| functional analysis of ljsut4, a vacuolar sucrose transporter from lotus japonicus. | sucrose transporters in the sut family are important for phloem loading and sucrose uptake into sink tissues. the recent localization of type iii suts atsut4 and hvsut2 to the vacuole membrane suggests that suts also function in vacuolar sucrose transport. the transport mechanism of type iii suts has not been analyzed in detail. ljsut4, a type iii sucrose transporter homolog from lotus japonicus, is expressed in nodules and its transport activity has not been previously investigated. in this rep ... | 2008 | 18618272 |
| substitution of the gene for chloroplast rps16 was assisted by generation of a dual targeting signal. | organelle (mitochondria and chloroplasts in plants) genomes lost a large number of genes after endosymbiosis occurred. even after this major gene loss, organelle genomes still lose their own genes, even those that are essential, via gene transfer to the nucleus and gene substitution of either different organelle origin or de novo genes. gene transfer and substitution events are important processes in the evolution of the eukaryotic cell. gene loss is an ongoing process in the mitochondria and ch ... | 2008 | 18453549 |
| characterization and comparison of intron structure and alternative splicing between medicago truncatula, populus trichocarpa, arabidopsis and rice. | alignment of transcripts and genome sequences yielded a set of alternatively spliced transcripts in four angiosperm genomes: three dicotyledon species medicago truncatula (medicago), populus trichocarpa (poplar) and arabidopsis thaliana (arabidopsis), and the monocotyledon oryzae sativa (rice). intron retention was the predominant mode of alternative splicing (as) in each species, consistent with previous reports for arabidopsis and rice. we analyzed the structure of 5'-splice junctions and obse ... | 2008 | 18438730 |
| low-coverage massively parallel pyrosequencing of cdnas enables proteomics in non-model species: comparison of a species-specific database generated by pyrosequencing with databases from related species for proteome analysis of pea chloroplast envelopes. | proteomics is a valuable tool for establishing and comparing the protein content of defined tissues, cell types, or subcellular structures. its use in non-model species is currently limited because the identification of peptides critically depends on sequence databases. in this study, we explored the potential of a preliminary cdna database for the non-model species pisum sativum created by a small number of massively parallel pyrosequencing (mpss) runs for its use in proteomics and compared it ... | 2008 | 18394738 |
| advances in development of transgenic pulse crops. | it is three decades since the first transgenic pulse crop has been developed. todate, genetic transformation has been reported in all the major pulse crops like vigna species, cicer arietinum, cajanus cajan, phaseolus spp, lupinus spp, vicia spp and pisum sativum, but transgenic pulse crops have not yet been commercially released. despite the crucial role played by pulse crops in tropical agriculture, transgenic pulse crops have not moved out from laboratories to large farm lands compared to the ... | 2008 | 18055156 |
| conserved microsynteny of npr1 with genes encoding a signal calmodulin-binding protein and a ck1-class protein kinase in beta vulgaris and two other eudicots. | npr1 is a gene of central importance in enabling plants to resist microbial attack. therefore, knowledge of nearby genes is important for genome analysis and possibly for improving disease resistance. in this study, systematic dna sequence analysis, gene annotation, and protein blasts were performed to determine genes near the npr1 gene in beta vulgaris l., medicago truncatula gaertn, and populus trichocarpa torr. & gray, and to access predicted function. microsynteny was discovered for npr1 wit ... | 2008 | 18989375 |
| microdiversity of burkholderiales associated with mycorrhizal and nonmycorrhizal roots of medicago truncatula. | the genetic diversity of bacterial communities associated with mycorrhizal and nonmycorrhizal roots of medicago truncatula was characterized by two approaches. firstly, phylogenetic analysis was performed on 164 partial 16s rrna gene-intergenic spacer (igs) sequences from operational taxonomic units previously shown to be preferentially associated with mycorrhizal roots. these sequences were distributed into three branches corresponding to comamonadaceae, oxalobacteraceae and rubrivivax subgroup ... | 2008 | 18507681 |
| the medicago truncatula ortholog of arabidopsis ein2, sickle, is a negative regulator of symbiotic and pathogenic microbial associations. | summary: the plant hormone ethylene negatively regulates bacterial infection and nodule formation in legumes in response to symbiotic rhizobia, but the molecular mechanism(s) of ethylene action in symbiosis remain obscure. we have identified and characterized multiple mutant alleles of the mtskl1 gene, which controls both ethylene sensitivity and nodule numbers. we show that this locus encodes the medicago truncatula ortholog of the arabidopsis ethylene signaling protein ein2. in addition to the ... | 2008 | 18435823 |
| a positive regulatory role for ljerf1 in the nodulation process is revealed by systematic analysis of nodule-associated transcription factors of lotus japonicus. | we have used reverse genetics to identify genes involved in legume-rhizobium symbiosis in lotus japonicus. we obtained the sequences of 20 putative transcription factors from previously reported large-scale transcriptome data. the transcription factors were classified according to their dna binding domains and patterns of expression during the nodulation process. we identified two homologues of medicago truncatula mthap2-1, which encodes a ccaat-binding protein and has been shown to play a role ... | 2008 | 18567832 |
| closely related members of the medicago truncatula pht1 phosphate transporter gene family encode phosphate transporters with distinct biochemical activities. | phosphorus is one of the essential mineral nutrients required by all living cells. plants assimilate phosphate (pi) from the soil, and their root systems encounter tremendous variation in pi concentration, both temporally and spatially. genome sequence data indicate that plant genomes contain large numbers of genes predicted to encode pi transporters, the functions of which are largely unexplored. here we present a comparative analysis of four very closely related pi transporters of the pht1 fam ... | 2008 | 18596039 |
| efd is an erf transcription factor involved in the control of nodule number and differentiation in medicago truncatula. | mechanisms regulating legume root nodule development are still poorly understood, and very few regulatory genes have been cloned and characterized. here, we describe efd (for ethylene response factor required for nodule differentiation), a gene that is upregulated during nodulation in medicago truncatula. the efd transcription factor belongs to the ethylene response factor (erf) group v, which contains ern1, 2, and 3, three erfs involved in nod factor signaling. the role of efd in the regulation ... | 2008 | 18978033 |
| plant host habitat and root exudates shape soil bacterial community structure. | the rhizosphere is active and dynamic in which newly generated carbon, derived from root exudates, and ancient carbon, in soil organic matter (som), are available for microbial growth. stable isotope probing (sip) was used to determine bacterial communities assimilating each carbon source in the rhizosphere of four plant species. wheat, maize, rape and barrel clover (medicago truncatula) were grown separately in the same soil under (13)co(2) (99% of atom (13)c) and dna extracted from rhizosphere ... | 2008 | 18754043 |
| the role of the plant cytoskeleton in the interaction between legumes and rhizobia. | the study of the symbiotic interaction between rhizobia and legumes represents a major theme in plant biology. this interaction results in the formation of nodules, root organs in which the bacteria reduce atmospheric nitrogen into ammonia, which can subsequently be utilized by the plant. the execution of the different developmental stages observed during nodule ontogenesis involves many cellular processes with significant roles for the plant cytoskeleton. a challenging question in cell biology ... | 2008 | 18778422 |
| a novel type of thioredoxin dedicated to symbiosis in legumes. | thioredoxins (trxs) constitute a family of small proteins in plants. this family has been extensively characterized in arabidopsis (arabidopsis thaliana), which contains six different trx types: f, m, x, and y in chloroplasts, o in mitochondria, and h mainly in cytosol. a detailed study of this family in the model legume medicago truncatula, realized here, has established the existence of two isoforms that do not belong to any of the types previously described. as no possible orthologs were furt ... | 2008 | 18614707 |
| evidence for the involvement in nodulation of the two small putative regulatory peptide-encoding genes mtralfl1 and mtdvl1. | nod factors are key bacterial signaling molecules regulating the symbiotic interaction between bacteria known as rhizobia and leguminous plants. studying plant host genes whose expression is affected by nod factors has given insights into early symbiotic signaling and development. here, we used a double supernodulating mutant line that shows increased sensitivity to nod factors to study the nod factor-regulated transcriptome. using microarrays containing more than 16,000 70-mer oligonucleotide p ... | 2008 | 18616408 |