| effects of medicago truncatula genetic diversity, rhizobial competition, and strain effectiveness on the diversity of a natural sinorhizobium species community. | we investigated the genetic diversity and symbiotic efficiency of 223 sinorhizobium sp. isolates sampled from a single mediterranean soil and trapped with four medicago truncatula lines. dna molecular polymorphism was estimated by capillary electrophoresis-single-stranded conformation polymorphism and restriction fragment length polymorphism on five loci (igs(nod), typa, virb11, avhb11, and the 16s rrna gene). more than 90% of the rhizobia isolated belonged to the sinorhizobium medicae species ( ... | 2008 | 18658290 |
| legume anchor markers link syntenic regions between phaseolus vulgaris, lotus japonicus, medicago truncatula and arachis. | we have previously described a bioinformatics pipeline identifying comparative anchor-tagged sequence (cats) loci, combined with design of intron-spanning primers. the derived anchor markers defining the linkage position of homologous genes are essential for evaluating genome conservation among related species and facilitate transfer of genetic and genome information between species. here we validate this global approach in the common bean and in the aa genome complement of the allotetraploid pe ... | 2008 | 18689902 |
| the model symbiotic association between medicago truncatula cv. jemalong and rhizobium meliloti strain 2011 leads to n-stressed plants when symbiotic n2 fixation is the main n source for plant growth. | a better knowledge of the nitrogen nutrition of medicago truncatula at the whole plant level and its modulation by environmental factors is a crucial step to reach a complete understanding of legume nitrogen nutrition. this study was based on the symbiotic system that is the most commonly used by the research community (m. truncatula cv. jemalong a17 x rhizobium meliloti strain 2011). plant nitrogen nutrition was analysed in relation to carbon nutrition, under a range of nitrate concentrations i ... | 2008 | 18703494 |
| the use of neutral and non-neutral ssrs to analyse the genetic structure of a tunisian collection of medicago truncatula lines and to reveal associations with eco-environmental variables. | in this study, we investigated the genetic diversity of a collection of 136 medicago truncatula lines from 10 tunisian natural populations collected in well-defined locations and in various ecological conditions of soil, salinity and water availability. the genetic diversity was evaluated using a set of 18 microsatellites (ssrs), representing the 8 chromosomes of m. truncatula. a neutrality test showed that 7 ssrs were non-neutral with evidence of balancing selection. the 11 neutral ssrs reveale ... | 2009 | 18704697 |
| alfalfa benefits from medicago truncatula: the rct1 gene from m. truncatula confers broad-spectrum resistance to anthracnose in alfalfa. | alfalfa is economically the most important forage legume worldwide. a recurrent challenge to alfalfa production is the significant yield loss caused by disease. although knowledge of molecular mechanisms underlying host resistance should facilitate the genetic improvement of alfalfa, the acquisition of such knowledge is hampered by alfalfa's tetrasomic inheritance and outcrossing nature. however, alfalfa is congeneric with the reference legume medicago truncatula, providing an opportunity to use ... | 2008 | 18719113 |
| 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 |
| imaging phosphatidylinositol 4-phosphate dynamics in living plant cells. | polyphosphoinositides represent a minor group of phospholipids, accounting for less than 1% of the total. despite their low abundance, these molecules have been implicated in various signalling and membrane trafficking events. phosphatidylinositol 4-phosphate (ptdins4p) is the most abundant polyphosphoinositide. (32)pi-labelling studies have shown that the turnover of ptdins4p is rapid, but little is known about where in the cell or plant this occurs. here, we describe the use of a lipid biosens ... | 2009 | 18785997 |
| flavones and flavonols play distinct critical roles during nodulation of medicago truncatula by sinorhizobium meliloti. | flavonoids play critical roles in legume-rhizobium symbiosis. however, the role of individual flavonoid compounds in this process has not yet been clearly established. we silenced different flavonoid-biosynthesis enzymes to generate transgenic medicago truncatula roots with different flavonoid profiles. silencing of chalcone synthase, the key entry-point enzyme for flavonoid biosynthesis led to flavonoid-deficient roots. silencing of isoflavone synthase and flavone synthase led to roots deficien ... | 2009 | 18786000 |
| comparative phylogenetic analysis of small gtp-binding genes of model legume plants and assessment of their roles in root nodules. | small gtp-binding genes play an essential regulatory role in a multitude of cellular processes such as vesicle-mediated intracellular trafficking, signal transduction, cytoskeletal organization, and cell division in plants and animals. medicago truncatula and lotus japonicus are important model plants for studying legume-specific biological processes such as nodulation. the publicly available online resources for these plants from websites such as http://www.ncbi.nih.gov, http://www.medicago.org ... | 2008 | 18849296 |
| abscisic acid coordinates nod factor and cytokinin signaling during the regulation of nodulation in medicago truncatula. | nodulation is tightly regulated in legumes to ensure appropriate levels of nitrogen fixation without excessive depletion of carbon reserves. this balance is maintained by intimately linking nodulation and its regulation with plant hormones. it has previously been shown that ethylene and jasmonic acid (ja) are able to regulate nodulation and nod factor signal transduction. here, we characterize the nature of abscisic acid (aba) regulation of nodulation. we show that application of aba inhibits no ... | 2008 | 18931020 |
| mechanism of infection thread elongation in root hairs of medicago truncatula and dynamic interplay with associated rhizobial colonization. | in temperate legumes, endosymbiotic nitrogen-fixing rhizobia gain access to inner root tissues via a specialized transcellular apoplastic compartment known as the infection thread (it). to study it development in living root hairs, a protocol has been established for medicago truncatula that allows confocal microscopic observations of the intracellular dynamics associated with it growth. fluorescent labeling of both the it envelope (atpip2;1-green fluorescent protein) and the host endoplasmic re ... | 2008 | 18931145 |
| bacterial effects on arbuscular mycorrhizal fungi and mycorrhiza development as influenced by the bacteria, fungi, and host plant. | bacterial strains from mycorrhizal roots (three belonging to comamonadaceae and one to oxalobacteraceae) and from non-mycorrhizal roots (two belonging to comamonadaceae) of medicago truncatula and two reference strains (collimonas fungivorans ter331 and pseudomonas fluorescens c7r12) were tested for their effect on the in vitro saprophytic growth of glomus mosseae beg12 and on its colonization of m. truncatula roots. only the oxalobacteraceae strain, isolated from barrel medic mycorrhizal roots, ... | 2009 | 18941805 |
| identification of sources of resistance to phoma medicaginis isolates in medicago truncatula sardi core collection accessions, and multigene differentiation of isolates. | abstract phoma medicaginis is a necrotrophic fungal pathogen, commonly found infecting the annual medic medicago truncatula. to differentiate eight p. medicaginis isolates, five gene regions were examined: actin, beta-tubulin, calmodulin, translation elongation factor 1-alpha (ef-1alpha), and the internal transcribed spacer ribosomal dna. sequence comparisons showed that specimens isolated from m. truncatula in western australia formed a group that was consistently different from, but allied to, ... | 2006 | 18943665 |
| different resistance mechanisms of medicago truncatula ecotypes against the rust fungus uromyces striatus. | abstract a pathosystem consisting of the model plant medicago truncatula and the rust fungus uromyces striatus was characterized. from a collection of 113 mostly european accessions of m. truncatula, the vast majority were found to be susceptible to u. striatus, whereas 5 accessions showed strong resistance reactions. stomatal surface characteristics, even if partly occluded, did not interfere with the ability of u. striatus germ tubes to infect. after penetration, the resistant ecotypes reacted ... | 2005 | 18943984 |
| characterization of resistance mechanisms to erysiphe pisi in medicago truncatula. | abstract in this work, we studied the resistance of 277 medicago truncatula accessions against powdery mildew and further characterized the defense mechanisms of resistant plants. ten resistant accessions were selected according to macroscopic assessment. histological studies showed a range of defense mechanisms, acting alone or combined, that impeded fungal development at different stages. some accessions allowed a reduced spore germination frequency compared with that of the susceptible contro ... | 2007 | 18944169 |
| 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 |
| the pea sym37 receptor kinase gene controls infection-thread initiation and nodule development. | phenotypic characterization of pea symbiotic mutants has provided a detailed description of the symbiosis with rhizobium leguminosarum bv. viciae strains. we show here that two allelic non-nodulating pea mutants, risnod4 and k24, are affected in the pssym37 gene, encoding a lysm receptor kinase similar to lotus japonicus nfr1 and medicago truncatula lyk3. phenotypic analysis of risnod4 and k24 suggests a role for the sym37 in regulation of infection-thread initiation and nodule development from ... | 2008 | 18986256 |
| production of transgenic barrel medic (medicago truncatula gaernt.) using the ipt-type mat vector system and impairment of recombinase-mediated excision events. | expression of the uida reporter gene was tested in transformation experiments of barrel medic (medicago truncatula gaertn.) with the ipt-type control vectors pipt5, pipt10 and pipt20 and distinct in vitro culture conditions. the highest gus expression levels were obtained with the pipt10 construct carrying the ipt gene under the control of the native ipt promoter and using kanamycin as selective agent. the ipt-shooty transformants, characterized by the absence of both rooting ability and apical ... | 2009 | 19011862 |
| colonization of adventitious roots of medicago truncatula by pseudomonas fluorescens c7r12 as affected by arbuscular mycorrhiza. | pseudomonas fluorescens c7r12 was previously shown to promote colonization of medicago truncatula roots by glomus mosseae beg12. to gain more insight into the interaction between c7r12 and beg12, the cell organization of c7r12 was characterized on adventitious roots mycorrhized or not with beg12 and on extraradical hyphae. bacterial cell observations were made using the immuno-fluorescence technique and confocal laser scanning microscopy. five types of cell organization, so-called organization t ... | 2008 | 19016872 |
| soybean proteomics and its application to functional analysis. | complete genome sequences, which are available for rice and arabidopsis, provide insights into many fundamental aspects of plant biology; they do not, however, address some important aspects of legume biology. legumes are important for maintenance of human health and as crops for sustainable agriculture. two model species of legume, lotus japonicus and medicago truncatula, have been the focus of projects on genome sequencing and functional genomics. a project aimed at sequencing the genome of th ... | 2009 | 19022415 |
| y4lo of rhizobium sp. strain ngr234 is a symbiotic determinant required for symbiosome differentiation. | type 3 (t3) effector proteins, secreted by nitrogen-fixing rhizobia with a bacterial t3 secretion system, affect the nodulation of certain host legumes. the open reading frame y4lo of rhizobium sp. strain ngr234 encodes a protein with sequence similarities to t3 effectors from pathogenic bacteria (the yopj effector family). transcription studies showed that the promoter activity of y4lo depended on the transcriptional activator ttsi. recombinant y4lo protein expressed in escherichia coli did not ... | 2009 | 19060155 |
| lack of trehalose catabolism in sinorhizobium species increases their nodulation competitiveness on certain host genotypes. | the role of host and bacterial genotypes in determining the competitiveness of trehalose utilization mutants of sinorhizobium meliloti and sinorhizobium medicae was investigated here. trehalose utilization mutants of s. meliloti and s. medicae were obtained by mutagenesis of their trehalose utilization gene thub. the mutant strains and the wild type were coinoculated on three cultivars of alfalfa (medicago sativa) and two cultivars of medicago truncatula and assessed for competitiveness in root ... | 2008 | 19086182 |
| stabilizing mechanisms in a legume-rhizobium mutualism. | preferential rewarding of more beneficial partners may stabilize mutualisms against the invasion of less beneficial, that is cheater, genotypes. recent evidence suggests that both partner choice and sanctioning may play roles in preventing the invasion of less-beneficial rhizobia in legume-rhizobium mutualisms. the importance of these mechanisms in natural communities, however, remains unclear. we grew 12 medicago truncatula maternal families with a mixture of three rhizobium strains from their ... | 2009 | 19087187 |
| elicitor-induced transcription factors for metabolic reprogramming of secondary metabolism in medicago truncatula. | exposure of medicago truncatula cell suspension cultures to pathogen or wound signals leads to accumulation of various classes of flavonoid and/or triterpene defense molecules, orchestrated via a complex signalling network in which transcription factors (tfs) are essential components. | 2008 | 19102779 |
| a portal for rhizobial genomes: rhizogate integrates a sinorhizobium meliloti genome annotation update with postgenome data. | sinorhizobium meliloti is a symbiotic soil bacterium of the alphaproteobacterial subdivision. like other rhizobia, s. meliloti induces nitrogen-fixing root nodules on leguminous plants. this is an ecologically and economically important interaction, because plants engaged in symbiosis with rhizobia can grow without exogenous nitrogen fertilizers. the s. meliloti-medicago truncatula (barrel medic) association is an important symbiosis model. the s. meliloti genome was published in 2001, and the m ... | 2009 | 19103235 |
| stimulation of nodulation in medicago truncatula by low concentrations of ammonium: quantitative reverse transcription pcr analysis of selected genes. | although mineral nitrogen generally has negative effects on nodulation in legume-rhizobia symbioses, low concentrations of ammonium stimulate nodulation in some legumes. in this study, the effects of ammonium and nitrate on growth, nodulation and expression of 2 nitrogen transport and 12 putative nodulation-related genes of the model symbiosis of medicago truncatula - sinorhizobium meliloti are investigated. after 3 weeks of hydroponic growth, whole-plant nodulation was enhanced in all the ammon ... | 2009 | 19140888 |
| an ste12 gene identified in the mycorrhizal fungus glomus intraradices restores infectivity of a hemibiotrophic plant pathogen. | mechanisms of root penetration by arbuscular mycorrhizal (am) fungi are unknown and investigations are hampered by the lack of transformation systems for these unculturable obligate biotrophs. early steps of host infection by hemibiotrophic fungal phytopathogens, sharing common features with those of am fungal colonization, depend on the transcription factor ste12. using degenerated primers and rapid amplification of cdna ends, we isolated the full-length cdna of an ste12-like gene, gintste, fro ... | 2009 | 19140944 |
| aer1, a major gene conferring resistance to aphanomyces euteiches in medicago truncatula. | aphanomyces euteiches is a major soilborne oomycete pathogen that infects various legume species, including pea and alfalfa. the model legume medicago truncatula has recently emerged as a valuable genetic system for understanding the genetic basis of resistance to a. euteiches in leguminous crops. the objective of this study was to identify genetic determinants of resistance to a broad host-range pea-infecting strain of a. euteiches in m. truncatula. two m. truncatula segregating populations of ... | 2009 | 19159312 |
| medicago truncatula (e)-beta-ocimene synthase is induced by insect herbivory with corresponding increases in emission of volatile ocimene. | virtually all plants are able to recognize attack by herbivorous insects and release volatile organic compounds (voc) in response. terpenes are the most abundant and varied class of insect-induced voc from plants. four genes encoding putative terpene synthases (mttps1, mttps2, mttps3 and mttps4) were shown to accumulate in medicago truncatula gaertn. in response to spodoptera exigua (hübner) feeding and methyl jasmonate treatment in a previous study [s.k. gomez, m.m. cox, j.c. bede, k.k. inoue, ... | 2009 | 19249223 |
| gras proteins form a dna binding complex to induce gene expression during nodulation signaling in medicago truncatula. | the symbiotic association of legumes with rhizobia involves bacterially derived nod factor, which is sufficient to activate the formation of nodules on the roots of the host plant. perception of nod factor by root hair cells induces calcium oscillations that are a component of the nod factor signal transduction pathway. perception of the calcium oscillations is a function of a calcium- and calmodulin-dependent protein kinase, and this activates nodulation gene expression via two gras domain tran ... | 2009 | 19252081 |
| characterization of root-knot nematode resistance in medicago truncatula. | root knot (meloidogyne spp.) and cyst (heterodera and globodera spp.) nematodes infect all important crop species, and the annual economic loss due to these pathogens exceeds $90 billion. we screened the worldwide accession collection with the root-knot nematodes meloidogyne incognita, m. arenaria and m. hapla, soybean cyst nematode (scn-heterodera glycines), sugar beet cyst nematode (sbcn-heterodera schachtii) and clover cyst nematode (clcn-heterodera trifolii), revealing resistant and suscepti ... | 2008 | 19259519 |
| induction of distinct defense-associated protein patterns in aphanomyces euteiches (oomycota)-elicited and -inoculated medicago truncatula cell-suspension cultures: a proteome and phosphoproteome approach. | a comprehensive proteomic approach was applied to investigate molecular events occurring upon inoculation of medicago truncatula cell-suspension cultures with the oomycete root pathogen aphanomyces euteiches. establishment of an inoculation assay in the cell cultures allowed a direct comparison between proteins induced by elicitation with a crude culture extract of the oomycete and by inoculation with a. euteiches zoospores representing the natural infection carrier. oxidative burst assays revea ... | 2009 | 19271957 |
| gene expression analysis of molecular mechanisms of defense induced in medicago truncatula parasitized by orobanche crenata. | the infection of medicago truncatula gaertn. roots with the obligate parasite orobanche crenata forsk. is a useful model for studying the molecular events involved in the legumes-parasite interaction. in order to gain insight into the identification of gene-regulatory elements involved in the resistance mechanism, the temporal expression pattern of ten defense-related genes was carried out using real-time quantitative reverse-transcription polymerase chain reaction assays. the induction of all o ... | 2009 | 19321356 |
| effects of indole-3-acetic acid on sinorhizobium meliloti survival and on symbiotic nitrogen fixation and stem dry weight production. | we evaluated the effects of the main auxin phytohormone, indole-3-acetic acid (iaa), on the central metabolism of sinorhizobium meliloti 1021. we either treated s. meliloti 1021 wild-type cells with 0.5 mm iaa, 1021+, or use a derivative, rd64, of the same strain harboring an additional pathway for iaa biosynthesis (converting tryptophan into iaa via indoleacetamide). we assayed the activity of tricarboxylic acid cycle (tca) key enzymes and found that activity of citrate synthase and alpha-ketog ... | 2009 | 19343341 |
| the lap1 myb transcription factor orchestrates anthocyanidin biosynthesis and glycosylation in medicago. | myb transcription factors help to control anthocyanin biosynthesis in plants, and ectopic expression of the arabidopsis production of anthocyanin pigment 1 (pap1) transcription factor activates the anthocyanin pathway in tobacco, suggesting the general utility of such factors for metabolic engineering of anthocyanins and anthocyanin-derived compounds such as proanthocyanidins (condensed tannins). however, pap1 does not activate anthocyanin biosynthesis in the model legume medicago truncatula or ... | 2009 | 19368693 |
| identification of qtl affecting seed mineral concentrations and content in the model legume medicago truncatula. | increasing the amount of bioavailable micronutrients such as iron and zinc in plant foods for human consumption is an international goal, intended especially for developing countries where micronutrient deficiencies are an ongoing health risk. legume seeds have the potential to provide the essential nutrients required by humans, but concentrations of several minerals are low when compared to other foods. in order to increase seed mineral concentrations, it is important to understand the genes an ... | 2009 | 19396421 |
| differing requirements for flavonoids during the formation of lateral roots, nodules and root knot nematode galls in medicago truncatula. | * in this study, we tested whether the organogenesis of symbiotic root nodules, lateral roots and root galls induced by parasitic root knot nematodes (meloidogyne javanica) was regulated by the presence of flavonoids in the roots of medicago truncatula. flavonoids accumulate in all three types of root organ, and have been hypothesized previously to be required for secondary root organogenesis because of their potential role as auxin transport regulators. * using rna interference to silence the f ... | 2009 | 19402878 |
| annexins - calcium- and membrane-binding proteins in the plant kingdom: potential role in nodulation and mycorrhization in medicago truncatula. | annexins belong to a family of multi-functional membrane- and ca(2+)-binding proteins. the characteristic feature of these proteins is that they can bind membrane phospholipids in a reversible, ca(2+)-dependent manner. while animal annexins have been known for a long time and are fairly well characterized, their plant counterparts were discovered only in 1989, in tomato, and have not been thoroughly studied yet. in the present review, we discuss the available information about plant annexins wit ... | 2009 | 19421430 |
| medicago truncatula improves salt tolerance when nodulated by an indole-3-acetic acid-overproducing sinorhizobium meliloti strain. | the abiotic stress resistance of wild-type sinorhizobium meliloti 1021 was compared with that of rd64, a derivative of the 1021 strain harbouring an additional pathway for the synthesis of indole-3-acetic acid (iaa), expressed in both free-living bacteria and bacteroids. it is shown here that the iaa-overproducing rd64 strain accumulated a higher level of trehalose as its endogenous osmolyte and showed an increased tolerance to several stress conditions (55 degrees c, 4 degrees c, uv-irradiation ... | 2009 | 19436044 |
| transcriptome analysis of a bacterially induced basal and hypersensitive response of medicago truncatula. | research using the well-studied model legume medicago truncatula has largely focused on rhizobium symbiosis, while little information is currently available for this species on pathogen-induced transcriptome changes. we have performed a transcriptome analysis of this species with the objective of studying the basal (br, no visible symptoms) and hypersensitive response (hr, plant cell death) in its leaves at 6 and at 24 h after infection by hr-negative (hrcc mutant) and hr-inducing pseudomonas sy ... | 2009 | 19466566 |
| dissection of bacterial wilt on medicago truncatula revealed two type iii secretion system effectors acting on root infection process and disease development. | ralstonia solanacearum is the causal agent of the devastating bacterial wilt disease, which colonizes susceptible medicago truncatula via the intact root tip. infection involves four steps: appearance of root tip symptoms, root tip cortical cell invasion, vessel colonization, and foliar wilting. we examined this pathosystem by in vitro inoculation of intact roots of susceptible or resistant m. truncatula with the pathogenic strain gmi1000. the infection process was type iii secretion system depe ... | 2009 | 19493968 |
| enod40 gene expression and cytokinin responses in the nonnodulating, nonmycorrhizal (nodmyc) mutant, masym3, of melilotus alba desr. | several nonnodulating, nonmycorrhizal (nod(-)myc(-)) mutants of melilotus alba desr. (white sweetclover) have been described. however, the details of their responses to sinorhizobium meliloti have not been fully elucidated. we investigated rhizobial entry and colonization using confocal scanning laser microscopy on the masym1-5 mutants and isolated an early nodulin (enod40) gene from wild-type m. alba. we focused on masym3, the least responsive of the mutants to s. meliloti and va-fungi, to dete ... | 2007 | 19516966 |
| changes in the profile of flavonoid accumulation in medicago truncatula leaves during infection with fungal pathogen phoma medicaginis. | medicago truncatula is a model species for the study of the unique secondary metabolism in legumes. lc/ms/ms analysis was used to identify and profile flavonoid glycoconjugates and free aglycones in leaves of m. truncatula (ecotype r108-1) infected with the fungal pathogen phoma medicaginis. use of a high resolution analyzer with a collision induced dissociation tandem mass spectrometer (cid ms/ms) permitted structural elucidation of target secondary metabolites and four new acylated flavone gly ... | 2009 | 19541494 |
| metabolic capacity of sinorhizobium (ensifer) meliloti strains as determined by phenotype microarray analysis. | sinorhizobium meliloti is a soil bacterium that fixes atmospheric nitrogen in plant roots. the high genetic diversity of its natural populations has been the subject of extensive analysis. recent genomic studies of several isolates revealed a high content of variable genes, suggesting a correspondingly large phenotypic differentiation among strains of s. meliloti. here, using the phenotype microarray (pm) system, hundreds of different growth conditions were tested in order to compare the metabol ... | 2009 | 19561177 |
| integrated metabolite and transcript profiling identify a biosynthetic mechanism for hispidol in medicago truncatula cell cultures. | metabolic profiling of elicited barrel medic (medicago truncatula) cell cultures using high-performance liquid chromatography coupled to photodiode and mass spectrometry detection revealed the accumulation of the aurone hispidol (6-hydroxy-2-[(4-hydroxyphenyl)methylidene]-1-benzofuran-3-one) as a major response to yeast elicitor. parallel, large-scale transcriptome profiling indicated that three peroxidases, mtprx1, mtprx2, and mtprx3, were coordinately induced with the accumulation of hispidol. ... | 2009 | 19571306 |
| composite medicago truncatula plants harbouring agrobacterium rhizogenes-transformed roots reveal normal mycorrhization by glomus intraradices. | composite plants consisting of a wild-type shoot and a transgenic root are frequently used for functional genomics in legume research. although transformation of roots using agrobacterium rhizogenes leads to morphologically normal roots, the question arises as to whether such roots interact with arbuscular mycorrhizal (am) fungi in the same way as wild-type roots. to address this question, roots transformed with a vector containing the fluorescence marker dsred were used to analyse am in terms o ... | 2009 | 19574251 |
| differential expression proteomics to investigate responses and resistance to orobanche crenata in medicago truncatula. | parasitic angiosperm orobanche crenata infection represents a major constraint for the cultivation of legumes worldwide. the level of protection achieved to date is either incomplete or ephemeral. hence, an efficient control of the parasite requires a better understanding of its interaction and associated resistance mechanisms at molecular levels. | 2009 | 19575787 |
| (homo)glutathione depletion modulates host gene expression during the symbiotic interaction between medicago truncatula and sinorhizobium meliloti. | under nitrogen-limiting conditions, legumes interact with symbiotic rhizobia to produce nitrogen-fixing root nodules. we have previously shown that glutathione and homoglutathione [(h)gsh] deficiencies impaired medicago truncatula symbiosis efficiency, showing the importance of the low m(r) thiols during the nodulation process in the model legume m. truncatula. in this study, the plant transcriptomic response to sinorhizobium meliloti infection under (h)gsh depletion was investigated using cdna- ... | 2009 | 19587096 |
| partial resistance of medicago truncatula to aphanomyces euteiches is associated with protection of the root stele and is controlled by a major qtl rich in proteasome-related genes. | a pathosystem between aphanomyces euteiches, the causal agent of pea root rot disease, and the model legume medicago truncatula was developed to gain insights into mechanisms involved in resistance to this oomycete. the f83005.5 french accession and the a17-jemalong reference line, susceptible and partially resistant, respectively, to a. euteiches, were selected for further cytological and genetic analyses. microscopy analyses of thin root sections revealed that a major difference between the tw ... | 2009 | 19656040 |
| symbiotic diversity of ensifer meliloti strains recovered from various legume species in tunisia. | ensifer meliloti (formerly sinorhizobium meliloti) was first considered as a specific microsymbiont of medicago, melilotus and trigonella. however, strains of e. meliloti were recovered from root nodules of various legume species and their symbiotic status still remains unclear. here, we further investigate the specificity of these strains. a collection of 47 e. meliloti strains isolated in tunisia from root nodules of medicago truncatula, medicago sativa, medicago ciliaris, medicago laciniata, ... | 2009 | 19665858 |
| mate transporters facilitate vacuolar uptake of epicatechin 3'-o-glucoside for proanthocyanidin biosynthesis in medicago truncatula and arabidopsis. | expression of the arabidopsis thaliana myb transcription factor transparent testa 2 (tt2) in medicago trunculata hairy roots induces both proanthocyanidin accumulation and the atp-dependent vacuolar/vesicular uptake of epicatechin 3'-o-glucoside; neither process is active in control roots that do, however, possess anthocyanidin 3-o-glucoside vacuolar uptake activity. a vacuolar membrane-localized multidrug and toxic compound extrusion (mate) transporter, medicago mate1, was identified at the mol ... | 2009 | 19684242 |
| osmotic shock improves tnt1 transposition frequency in medicago truncatula cv jemalong during in vitro regeneration. | insertion mutant collections are powerful tools for genetic studies in plants. although large-scale insertional mutagenesis using t-dna is not feasible in legumes, the tnt1 tobacco retrotransposon can be used as a very efficient mutagen in the medicago truncatula r108 genotype. in this article, we show that tnt1 can also be exploited to create insertional mutants via transformation and/or regeneration in the reference cultivar jemalong. tnt1 insertional mutagenesis in jemalong following agrobact ... | 2009 | 19688215 |
| a nuclear-targeted cameleon demonstrates intranuclear ca2+ spiking in medicago truncatula root hairs in response to rhizobial nodulation factors. | lipochitooligosaccharide nodulation factors (nfs) secreted by endosymbiotic nitrogen-fixing rhizobia trigger ca(2+) spiking in the cytoplasmic perinuclear region of host legume root hairs. to determine whether nfs also elicit ca(2+) responses within the plant cell nucleus we have made use of a nucleoplasmin-tagged cameleon (nupyc2.1). confocal microscopy using this nuclear-specific calcium reporter has revealed sustained and regular ca(2+) spiking within the nuclear compartment of medicago trunc ... | 2009 | 19700563 |
| can differences of nitrogen nutrition level among medicago truncatula genotypes be assessed non-destructively?: probing with a recombinant inbred lines population. | the international consensus on medicago truncatula as a model system has lead to the development of powerful approaches for dissecting the genetic and molecular bases of legume nitrogen nutrition. however, such approaches now come up against a poor knowledge of the phenotypic traits that should be used for the large-scale screening of the genotypic variability associated with nitrogen nutrition. this issue was unravelled in a previous report, in which an ecophysiological approach allowed a bette ... | 2009 | 19704700 |
| medicago n2-fixing symbiosomes acquire the endocytic identity marker rab7 but delay the acquisition of vacuolar identity. | rhizobium bacteria form n(2)-fixing organelles, called symbiosomes, inside the cells of legume root nodules. the bacteria are generally thought to enter the cells via an endocytosis-like process. to examine this, we studied the identity of symbiosomes in relation to the endocytic pathway. we show that in medicago truncatula, the small gtpases rab5 and rab7 are endosomal membrane identity markers, marking different (partly overlapping) endosome populations. although symbiosome formation is consid ... | 2009 | 19734435 |
| legume small gtpases and their role in the establishment of symbiotic associations with rhizobium spp. | small gtp-binding genes act as molecular switches regulating myriad of cellular processes including vesicle-mediated intracellular trafficking, signal transduction, cytoskeletal reorganization and cell division in plants and animals. even though these genes are well conserved both functionally and sequentially across whole eukaryotae, occasional lineage-specific diversification in some plant species in terms of both functional and expressional characteristics have been reported. hence, comparati ... | 2009 | 19794839 |
| identification and characterization of mtmtp1, a zn transporter of cdf family, in the medicago truncatula. | zn is an essential micronutrient in plants, and the mechanisms of zn homeostasis are under intensive study. in this report, we have identified mtmtp1, a zn transporter of the cdf family in the legume model plant medicago truncatula. the orf of the mtmtp1 cdna encodes a protein consisting of 407 amino acid residues with a predicted molecular mass of 45 kda. like other metal tolerance proteins (mtps) in plants, heterologous expression of mtmtp1 can complement the zn-susceptible zrc1 cot1 yeast dou ... | 2009 | 19800247 |
| cloning and characterization of a functional flavanone-3ß-hydroxylase gene from medicago truncatula. | as a key enzyme in the biosynthesis of flavonols, anthocyanidins and proanthocyanidins, flavanone-3ß-hydroxylase (f3h) plays very important roles in plant stress response. a putative flavanone-3ß-hydroxylase gene from medicago truncatula (mtf3h), a model legume species, was identified from a bio-data analysis platform. it was speculated to be induced by salt stress based on the outcomes of the analysis platform. the complementary dna (cdna) consists of 1499 bp with an open reading frame (orf) of ... | 2010 | 19888675 |
| the medicago truncatula n5 gene encoding a root-specific lipid transfer protein is required for the symbiotic interaction with sinorhizobium meliloti. | the medicago truncatula n5 gene is induced in roots after sinorhizobium meliloti infection and it codes for a putative lipid transfer protein (ltp), a family of plant small proteins capable of binding and transferring lipids between membranes in vitro. various biological roles for plant ltp in vivo have been proposed, including defense against pathogens and modulation of plant development. the aim of this study was to shed light on the role of mtn5 in the symbiotic interaction between m. truncat ... | 2009 | 19888823 |
| the rap1 gene confers effective, race-specific resistance to the pea aphid in medicago truncatula independent of the hypersensitive reaction. | plant resistance to pathogens is commonly associated with a hypersensitive response (hr), but the degree to which the hr is responsible for incompatibility is subject to debate. resistance to aphids is likely to share features with resistance to pathogens but is less well understood. here, we report effective resistance to the pea aphid acyrthosiphon pisum in medicago truncatula. aphids lost weight and died rapidly (within two days) on the resistant genotype jemalong, which developed necrotic le ... | 2009 | 19888829 |
| differential gel electrophoresis (dige) to quantitatively monitor early symbiosis- and pathogenesis-induced changes of the medicago truncatula root proteome. | symbiosis- and pathogenesis-related early protein induction patterns in the model legume medicago truncatula were analysed with two-dimensional differential gel electrophoresis. two symbiotic soil microorganisms (glomus intraradices, sinorhizobium meliloti) were used in single infections and in combination with a secondary pathogenic infection by the oomycete aphanomyces euteiches. proteomic analyses performed 6 and 24h after inoculations led to identification of 87 differentially induced protei ... | 2010 | 19895911 |
| analysis and modeling of the integrative response of medicago truncatula to nitrogen constraints. | an integrative biology approach was conducted in medicago truncatula for: (i) unraveling the coordinated regulation of no3-, nh4+ and n(2) acquisition by legumes to fulfill the plant n demand; and (ii) modeling the emerging properties occurring at the whole plant level. upon localized addition of a high level of mineral n, the three n acquisition pathways displayed similar systemic feedback repression to adjust n acquisition capacities to the plant n status. genes associated to these responses w ... | 2009 | 19909924 |
| red clover coumarate 3'-hydroxylase (cyp98a44) is capable of hydroxylating p-coumaroyl-shikimate but not p-coumaroyl-malate: implications for the biosynthesis of phaselic acid. | red clover (trifolium pratense) leaves accumulate several mumol of phaselic acid [2-o-caffeoyl-l-malate] per gram fresh weight. post-harvest oxidation of such o-diphenols to o-quinones by endogenous polyphenol oxidases (ppo) prevents breakdown of forage protein during storage. forages like alfalfa (medicago sativa) lack both foliar ppo activity and o-diphenols. consequently, breakdown of their protein upon harvest and storage results in economic losses and release of excess nitrogen into the env ... | 2010 | 19921248 |
| identification of flavone phytoalexins and a pathogen-inducible flavone synthase ii gene (sbfnsii) in sorghum. | following inoculation with the anthracnose pathogen colletotrichum sublineolum, seedlings of the sorghum resistant cultivar sc748-5 showed more rapid and elevated accumulation of luteolin than the susceptible cultivar btx623. on the other hand, apigenin was the major flavone detected in infected btx623 seedlings. luteolin was demonstrated to show stronger inhibition of spore germination of c. sublineolum than apigenin. because of their pathogen-inducible and antifungal nature, both flavone aglyc ... | 2010 | 20007684 |
| a complex genetic network involving a broad-spectrum locus and strain-specific loci controls resistance to different pathotypes of aphanomyces euteiches in medicago truncatula. | a higher understanding of genetic and genomic bases of partial resistance in plants and their diversity regarding pathogen variability is required for a more durable management of resistance genetic factors in sustainable cropping systems. in this study, we investigated the diversity of genetic factors involved in partial resistance to aphanomyces euteiches, a very damaging pathogen on pea and alfalfa, in medicago truncatula. a mapping population of 178 recombinant inbred lines, from the cross f ... | 2010 | 20012740 |
| the mtsnf4b subunit of the sucrose non-fermenting-related kinase complex connects after-ripening and constitutive defense responses in seeds of medicago truncatula. | dormant seeds are capable of remaining alive in the hydrated state for extended periods of time without losing vigor, until environmental cues or after-ripening result in the release of dormancy. here, we investigated the possible role of the regulatory subunit of the sucrose non-fermenting-related kinase complex, mtsnf4b, in dormancy of medicago truncatula seeds. expression of mtsnf4b and its involvement in a high-molecular-weight complex are found in dormant seeds, whereas imbibition of fully ... | 2010 | 20015062 |
| plant flotillins are required for infection by nitrogen-fixing bacteria. | to establish compatible rhizobial-legume symbioses, plant roots support bacterial infection via host-derived infection threads (its). here, we report the requirement of plant flotillin-like genes (flots) in sinorhizobium meliloti infection of its host legume medicago truncatula. flotillins in other organisms have roles in viral pathogenesis, endocytosis, and membrane shaping. we identified seven flot genes in the m. truncatula genome and show that two, flot2 and flot4, are strongly up-regulated ... | 2010 | 20018678 |
| npr1 protein regulates pathogenic and symbiotic interactions between rhizobium and legumes and non-legumes. | legumes are unique in their ability to establish symbiotic interaction with rhizobacteria from rhizobium genus, which provide them with available nitrogen. nodulation factors (nfs) produced by rhizobium initiate legume root hair deformation and curling that entrap the bacteria, and allow it to grow inside the plant. in contrast, legumes and non-legumes activate defense responses when inoculated with pathogenic bacteria. one major defense pathway is mediated by salicylic acid (sa). sa is sensed a ... | 2009 | 20027302 |
| a novel rna-binding peptide regulates the establishment of the medicago truncatula-sinorhizobium meliloti nitrogen-fixing symbiosis. | plants use a variety of small peptides for cell to cell communication during growth and development. leguminous plants are characterized by their ability to develop nitrogen-fixing nodules via an interaction with symbiotic bacteria. during nodule organogenesis, several so-called nodulin genes are induced, including large families that encode small peptides. using a three-hybrid approach in yeast cells, we identified two new small nodulins, mtsnarp1 and mtsnarp2 (for small nodulin acidic rna-bind ... | 2010 | 20042020 |
| presence of three mycorrhizal genes in the common ancestor of land plants suggests a key role of mycorrhizas in the colonization of land by plants. | *the colonization of land by plants fundamentally altered environmental conditions on earth. plant-mycorrhizal fungus symbiosis likely played a key role in this process by assisting plants to absorb water and nutrients from soil. *here, in a diverse set of land plants, we investigated the evolutionary histories and functional conservation of three genes required for mycorrhiza formation in legumes and rice (oryza sativa), dmi1, dmi3 and ipd3. *the genes were isolated from nearly all major plant ... | 2010 | 20059702 |
| sinorhizobium meliloti 1021 loss-of-function deletion mutation in chvi and its phenotypic characteristics. | bacterial two-component regulatory systems (tcs) are common components of complex regulatory networks and cascades. in sinorhizobium meliloti, the tcs exos/chvi controls exopolysaccharide succinoglycan production and flagellum biosynthesis. although this system plays a crucial role in establishing the symbiosis between s. meliloti and its host plant, it is not well characterized. attempts to generate complete loss-of-function mutations in either exos or chvi in s. meliloti have been unsuccessful ... | 2010 | 20064059 |
| suppression of hypernodulation in soybean by a leaf-extracted, nark- and nod factor-dependent, low molecular mass fraction. | *legumes regulate the number of nodules they form via a process called autoregulation of nodulation (aon). this involves a shoot-derived inhibitor (sdi) molecule that is synthesized in the shoots and is transported down to the roots where it inhibits further nodule development. *to characterize sdi, we developed a novel feeding bioassay. this involved feeding aqueous leaf extracts directly into the petiole of hypernodulating and supernodulating nark mutant plants of glycine max (soybean). these ... | 2010 | 20100211 |
| s-glycoprotein-like protein regulates defense responses in nicotiana plants against ralstonia solanacearum. | rsrga4 (for ralstonia solanacearum-responsive gene a4) encodes a polypeptide similar to s-locus glycoprotein (sgp) from brassica rapa and sgp-like proteins from ipomoea trifida and medicago truncatula. therefore, we designated rsrga4 as ntsglp (for nicotiana tabacum sgp-like protein) and nbsglp (its nicotiana benthamiana ortholog). nbsglp is expressed in root, leaf, petal, gynoecium, and stamen. expression of nbsglp was strongly induced by inoculation with an avirulent strain of r. solanacearum ... | 2010 | 20118275 |
| a remorin protein interacts with symbiotic receptors and regulates bacterial infection. | remorin proteins have been hypothesized to play important roles during cellular signal transduction processes. induction of some members of this multigene family has been reported during biotic interactions. however, no roles during host-bacteria interactions have been assigned to remorin proteins until now. we used root nodule symbiosis between medicago truncatula and sinorhizobium meliloti to study the roles of a remorin that is specifically induced during nodulation. here we show that this ol ... | 2010 | 20133878 |
| site and plant species are important determinants of the methylobacterium community composition in the plant phyllosphere. | the plant phyllosphere constitutes a habitat for numerous microorganisms; among them are members of the genus methylobacterium. owing to the ubiquitous occurrence of methylobacteria on plant leaves, they represent a suitable target for studying plant colonization patterns. the influence of the factor site, host plant species, time and the presence of other phyllosphere bacteria on methylobacterium community composition and population size were evaluated in this study. leaf samples were collected ... | 2010 | 20164863 |
| plant peptides govern terminal differentiation of bacteria in symbiosis. | legume plants host nitrogen-fixing endosymbiotic rhizobium bacteria in root nodules. in medicago truncatula, the bacteria undergo an irreversible (terminal) differentiation mediated by hitherto unidentified plant factors. we demonstrated that these factors are nodule-specific cysteine-rich (ncr) peptides that are targeted to the bacteria and enter the bacterial membrane and cytosol. obstruction of ncr transport in the dnf1-1 signal peptidase mutant correlated with the absence of terminal bacteri ... | 2010 | 20185722 |
| a nodule-specific protein secretory pathway required for nitrogen-fixing symbiosis. | the nitrogen-fixing symbiosis between sinorhizobium meliloti and its leguminous host plant medicago truncatula occurs in a specialized root organ called the nodule. bacteria that are released into plant cells are surrounded by a unique plant membrane compartment termed a symbiosome. we found that in the symbiosis-defective dnf1 mutant of m. truncatula, bacteroid and symbiosome development are blocked. we identified the dnf1 gene as encoding a subunit of a signal peptidase complex that is highly ... | 2010 | 20185723 |
| role of the sinorhizobium meliloti global regulator hfq in gene regulation and symbiosis. | the rna-binding protein hfq is a global regulator which controls diverse cellular processes in bacteria. to begin understanding the role of hfq in the sinorhizobium meliloti-medicago truncatula nitrogen-fixing symbiosis, we defined free-living and symbiotic phenotypes of an hfq mutant. over 500 transcripts were differentially accumulated in the hfq mutant of s. meliloti rm1021 when grown in a shaking culture. consistent with transcriptome-wide changes, the hfq mutant displayed dramatic alteratio ... | 2010 | 20192823 |
| partner choice in medicago truncatula-sinorhizobium symbiosis. | in nitrogen-fixing symbiosis, plant sanctions against ineffective bacteria have been demonstrated in previous studies performed on soybean and yellow bush lupin, both developing determinate nodules with bradyrhizobium sp. strains. in this study, we focused on the widely studied symbiotic association medicago truncatula-sinorhizobium meliloti, which forms indeterminate nodules. using two strains isolated from the same soil and displaying different nitrogen fixation phenotypes on the same fixed pl ... | 2010 | 20200033 |
| differentiation of symbiotic cells and endosymbionts in medicago truncatula nodulation are coupled to two transcriptome-switches. | the legume plant medicago truncatula establishes a symbiosis with the nitrogen-fixing bacterium sinorhizobium meliloti which takes place in root nodules. the formation of nodules employs a complex developmental program involving organogenesis, specific cellular differentiation of the host cells and the endosymbiotic bacteria, called bacteroids, as well as the specific activation of a large number of plant genes. by using a collection of plant and bacterial mutants inducing non-functional, fix(-) ... | 2010 | 20209049 |
| isolation and characterization of a harvest-inducible gene hi11 and its promoter from alfalfa. | the harvesting and storing of alfalfa is a routine practice in the agricultural industry worldwide. to investigate gene expression in harvested alfalfa, cdna from non-harvested and harvested plants in the field was subjected to subtractive hybridization to identify, in particular, those genes that are induced by the harvesting treatment. one cdna clone, named hi11, was isolated and analysed. the full length cdna of the hi11 gene was cloned by race amplification. the hi11 gene, which has high hom ... | 2011 | 20238171 |
| proteomic analysis of medicago truncatula root plastids. | despite the recognized importance of non-photosynthetic plastids in a wide array of plant processes, the root plastid proteome of soil-grown plants still remains to be explored. in this study, we used a protocol allowing the isolation of medicago truncatula root plastids with sufficient protein recovery and purity for their subsequent in-depth analysis by nanoscale capillary lc-ms/ms. besides providing the first picture of a root plastid proteome, the results obtained highlighted the identificat ... | 2010 | 20336678 |
| effects of water deficit stress on growth, water relations and osmolyte accumulation in medicago truncatula and m. laciniata populations. | the effects of water stress were investigated in two tunisian medicago truncatula populations collected from arid (mt-173) and sub-humid (mt-664) climates and two tunisian m. laciniata populations originating from arid (ml-173) and semi-arid (ml-345) regions. after a pre-treatment phase (24 days after sowing, das) of watering at 100% of field capacity (fc), the plants were either irrigated at 100% fc or at only 33% fc. after 12 days of treatment (36 das), one lot of dehydrated plants was rewater ... | 2010 | 20338538 |
| genomic and coexpression analyses predict multiple genes involved in triterpene saponin biosynthesis in medicago truncatula. | saponins, an important group of bioactive plant natural products, are glycosides of triterpenoid or steroidal aglycones (sapogenins). saponins possess many biological activities, including conferring potential health benefits for humans. however, most of the steps specific for the biosynthesis of triterpene saponins remain uncharacterized at the molecular level. here, we use comprehensive gene expression clustering analysis to identify candidate genes involved in the elaboration, hydroxylation, ... | 2010 | 20348429 |
| nitrogen fixation persists under conditions of salt stress in transgenic medicago truncatula plants expressing a cyanobacterial flavodoxin. | several recent studies have demonstrated that the expression of a cyanobacterial flavodoxin in plants can provide tolerance to a wide range of environmental stresses. indeed, this strategy has been proposed as a potentially powerful biotechnological tool to generate multiple-tolerant crops. to determine whether flavodoxin expression specifically increased tolerance to salt stress and whether it might also preserve legume nitrogen fixation under saline conditions, the flavodoxin gene was introduc ... | 2010 | 20353403 |
| signaling ltps: a new plant ltps sub-family? | numerous plant non specific lipid transfer protein (nsltps) have been characterized for their antimicrobial activity, suggesting for these proteins a direct role in the protection against pathogenic microorganisms. another group of ltps seems to be involved in structural events in the extracellular matrix through binding and transport of hydrophobic molecules. more recently, some ltps putatively involved in the symbiotic interaction between legumes and rhizobia have been identified. we investiga ... | 2010 | 20404561 |
| phymatotrichum (cotton) root rot caused by phymatotrichopsis omnivora: retrospects and prospects. | phymatotrichum (cotton or texas) root rot is caused by the soil-borne fungus phymatotrichopsis omnivora (duggar) hennebert. the broad host range of the fungus includes numerous crop plants, such as alfalfa and cotton. together with an overview of existing knowledge, this review is aimed at discussing the recent molecular and genomic approaches that have been undertaken to better understand the disease development at the molecular level with the ultimate goal of developing resistant germplasm. ta ... | 2010 | 20447281 |
| infection-specific activation of the medicago truncatula enod11 early nodulin gene promoter during actinorhizal root nodulation. | the mtenod11 gene from medicago truncatula is widely used as an early infection-related molecular marker for endosymbiotic associations involving both rhizobia and arbuscular mycorrhizal fungi. in this article, heterologous expression of the mtenod11 promoter has been studied in two actinorhizal trees, casuarina glauca and allocasuarina verticillata. transgenic c. glauca and a. verticillata expressing a promtenod11::beta-glucuronidase (gus) fusion were generated and the activation of the transge ... | 2010 | 20459313 |
| the response to nitric oxide of the nitrogen-fixing symbiont sinorhizobium meliloti. | nitric oxide (no) is crucial in animal- and plant-pathogen interactions, during which it participates in host defense response and resistance. indications for the presence of no during the symbiotic interaction between the model legume medicago truncatula and its symbiont sinorhizobium meliloti have been reported but the role of no in symbiosis is far from being elucidated. our objective was to understand the role or roles played by no in symbiosis. as a first step toward this goal, we analyzed ... | 2010 | 20459314 |
| molecular and cytological responses of medicago truncatula to erysiphe pisi. | summary powdery mildew is an economically important disease in a number of crop legumes; however, little is known about resistance to the disease in these species. to gain a better understanding of the genetics of resistance and plant responses to powdery mildew in legumes, we developed a pathosystem with medicago truncatula and erysiphe pisi. screening accessions of m. truncatula identified genotypes that are highly susceptible, moderately resistant and highly resistant to the fungus. in the hi ... | 2007 | 20507501 |
| root rot disease of legumes caused by aphanomyces euteiches. | the oomycete genus aphanomyces houses plant and animal pathogens found in both terrestrial and aquatic habitats. aphanomyces euteiches drechs. causes seedling damping off and root rot diseases on many legumes. it is the most devastating pea (pisum sativum) disease in several countries, causing up to 80% losses each year. this strictly soil-borne pathogen may survive many years in soil and no efficient chemical control is currently available. the only way to control the disease is to avoid cultiv ... | 2007 | 20507520 |
| improvement of phosphate solubilization and medicago plant yield by an indole-3-acetic acid-overproducing strain of sinorhizobium meliloti. | nitrogen (n) and phosphorus (p) are the most limiting factors for plant growth. some microorganisms improve the uptake and availability of n and p, minimizing chemical fertilizer dependence. it has been published that the rd64 strain, a sinorhizobium meliloti 1021 strain engineered to overproduce indole-3-acetic acid (iaa), showed improved nitrogen fixation ability compared to the wild-type 1021 strain. here, we present data showing that rd64 is also highly effective in mobilizing p from insolub ... | 2010 | 20511434 |
| expression pattern suggests a role of mir399 in the regulation of the cellular response to local pi increase during arbuscular mycorrhizal symbiosis. | many plants improve their phosphate (pi) availability by forming mutualistic associations with arbuscular mycorrhizal (am) fungi. pi-repleted plants are much less colonized by am fungi than pi-depleted plants. this indicates a link between plant pi signaling and am development. micrornas (mir) of the 399 family are systemic pi-starvation signals important for maintenance of pi homeostasis in arabidopsis thaliana and might also qualify as signals regulating am development in response to pi availa ... | 2010 | 20521954 |
| backbone-free transformation of barrel medic (medicago truncatula) with a medicago-derived transfer dna. | in the present work, agrobacterium tumefaciens-mediated genetic transformation of the model legume medicago truncatula gaertn. (barrel medic) was carried out using the psim843 vector that contains a medicago-derived transfer dna, delineated by a 25-bp sequence homologous to bacterial t-dna borders. the transfer dna contains an expression cassette for the nptii (neomycin phosphotransferase) gene and is flanked by an expression cassette for the backbone integration marker gene ipt (isopentenyl tra ... | 2010 | 20571798 |
| transcription factor profiling leading to the identification of putative transcription factors involved in the medicago truncatula-uromyces striatus interaction. | understanding the host response to uromyces sp., the causal agent of rust in many crop species, is crucial in elucidating the specific biology of rust resistance. in an attempt to unravel the medicago truncatula-u. striatus interaction, we performed a global analysis of transcription factor (tf) expression in resistant and susceptible accessions of the model plant m. truncatula during infection with u. striatus. for this purpose, an established qpcr platform was applied, consisting of specific p ... | 2010 | 20582581 |
| characterization and expression analysis of medicago truncatula rop gtpase family during the early stage of symbiosis. | rops (rho-related gtpases of plants) are small gtpases that are plant-specific signaling proteins. they act as molecular switches in a variety of developmental processes. in this study, seven cdna clones coding for rop gtpases have been isolated in medicago truncatula, and conserved and divergent domains are identified in these predicted mtrop proteins. phylogenetic analysis has indicated that mtrops are distributed into groups ii, iii, iv but group i. mtrop genes are expressed in various tissue ... | 2010 | 20590994 |
| non-protein-coding rnas and their interacting rna-binding proteins in the plant cell nucleus. | the complex responses of eukaryotic cells to external factors are governed by several transcriptional and post-transcriptional processes. several of them occur in the nucleus and have been linked to the action of non-protein-coding rnas (or npcrnas), both long and small npcrnas, that recently emerged as major regulators of gene expression. regulatory npcrnas acting in the nucleus include silencing-related rnas, intergenic npcrnas, natural antisense rnas, and other aberrant rnas resulting from th ... | 2010 | 20603381 |
| medicago truncatula proteomics. | legumes (fabaceae) are unique in their ability to enter into an elaborate symbiosis with nitrogen-fixing rhizobial bacteria. rhizobia-legume (rl) symbiosis represents one of the most productive nitrogen-fixing systems and effectively renders the host plants to be more or less independent of other nitrogen sources. due to high protein content, legumes are among the most economically important crop families. beyond that, legumes consist of over 16,000 species assigned to 650 genera. in most cases, ... | 2010 | 20621211 |
| how many peas in a pod? legume genes responsible for mutualistic symbioses underground. | the nitrogen-fixing symbiosis between legume plants and rhizobium bacteria is the most prominent plant-microbe endosymbiotic system and, together with mycorrhizal fungi, has critical importance in agriculture. the introduction of two model legume species, lotus japonicus and medicago truncatula, has enabled us to identify a number of host legume genes required for symbiosis. a total of 26 genes have so far been cloned from various symbiotic mutants of these model legumes, which are involved in r ... | 2010 | 20660226 |