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expression dynamics of the medicago truncatula transcriptome during the symbiotic interaction with sinorhizobium meliloti: which role for nitric oxide?medicago truncatula is one of the most studied model plants. nevertheless, the genome of this legume remains incompletely determined. we used rna-seq to characterize the transcriptome during the early organogenesis of the nodule and during its functioning. we detected 37,333 expressed transcription units; to our knowledge, 1,670 had never been described before and were functionally annotated. we identified 7,595 new transcribed regions, mostly corresponding to 5' and 3' untranslated region exten ...201223136381
transcriptional responses toward diffusible signals from symbiotic microbes reveal mtnfp- and mtdmi3-dependent reprogramming of host gene expression by arbuscular mycorrhizal fungal lipochitooligosaccharides.the formation of root nodules and arbuscular mycorrhizal (am) roots is controlled by a common signaling pathway including the calcium/calmodulin-dependent kinase doesn't make infection3 (dmi3). while nodule initiation by lipochitooligosaccharide (lco) nod factors is well characterized, diffusible am fungal signals were only recently identified as sulfated and nonsulfated lcos. irrespective of different outcomes, the perception of symbiotic lcos in medicago truncatula is mediated by the lysm rece ...201222652128
"ménage à trois": the presence/absence of thyme shapes the mutualistic interaction between the host plant medicago truncatula (fabaceae) and its symbiotic bacterium sinorhizobium meliloti.the long-term maintenance of specialized mutualisms remains an evolutionary puzzle. recent focus has been on factors governing the stability of these mutualisms, including sanctions by the host, partner choice, and coevolutionary constraint, that is, the genetic correlation (r(g)) between fitness of both partners. so far these studies have been typically carried out in a single environment. here, we ask if the genetic correlation between fitness of the host plant medicago truncatula (fabaceae) a ...201222957171
ros production during symbiotic infection suppresses pathogenesis-related gene expression.leguminous plants have exclusive ability to form symbiotic relationship with soil bacteria of the genus rhizobium. symbiosis is a complex process that involves multiple molecular signaling activities, such as calcium fluxes, production of reactive oxygen species (ros) and synthesis of nodulation genes. we analyzed the role of ros in defense gene expression in medicago truncatula during symbiosis and pathogenesis. studies in arabidopsis thaliana showed that the induction of pathogenesis-related ( ...201222499208
natural diversity in the model legume medicago truncatula allows identifying distinct genetic mechanisms conferring partial resistance to verticillium wilt.verticillium wilt is a major threat to alfalfa (medicago sativa) and many other crops. the model legume medicago truncatula was used as a host for studying resistance and susceptibility to verticillium albo-atrum. in addition to presenting well-established genetic resources, this wild plant species enables to investigate biodiversity of the response to the pathogen and putative crosstalk between disease and symbiosis. symptom scoring after root inoculation and modelling of disease curves allowed ...201223213135
structural changes in medicago truncatula root nodules caused by short-term aluminum stress.aluminum in the form of al(3+) is one of the most toxic heavy metal pollutants in nature and its effects are primarily root-related. roots of medicago truncatula exposed to 50 μm of alcl3 for 2 h and 24 h were examined by light and electron microscopy. changes in the appearance of the host cells, infection threads and bacteroidal tissue occurred during the first 2 h of al stress. microscopic observations showed that aluminum: (1) induced thickening of plant cell and infection threads (its) walls ...201223482822
proteomic analysis by two-dimensional differential in gel electrophoresis (2d dige) of the early response of pisum sativum to orobanche crenata.crenate broomrape (orobanche crenata) is considered to be the major constraint for legume crops in mediterranean countries. strategies of control have been developed, but only marginal successes have been achieved. for the efficient control of the parasite, a better understanding of its interaction and associated resistance mechanisms at the molecular level is required. the pea response to this parasitic plant and the molecular basis of the resistance was studied using a proteomic approach based ...201221920908
an overall evaluation of the resistance (r) and pathogenesis-related (pr) superfamilies in soybean, as compared with medicago and arabidopsis.plants have the ability to recognize and respond to a multitude of pathogens, resulting in a massive reprogramming of the plant to activate defense responses including resistance (r) and pathogenesis-related (pr) genes. abiotic stresses can also activate pr genes and enhance pathogen resistance, representing valuable genes for breeding purposes. the present work offers an overview of soybean r and pr genes present in the genosoja (brazilian soybean genome consortium) platform, regarding their st ...201222802711
interaction between medicago truncatula and pseudomonas fluorescens: evaluation of costs and benefits across an elevated atmospheric co(2).soil microorganisms play a key role in both plants nutrition and health. their relation with plant varies from mutualism to parasitism, according to the balance of costs and benefits for the two partners of the interaction. these interactions involved the liberation of plant organic compounds via rhizodeposition. modification of atmospheric co(2) concentration may affect rhizodeposition and as a consequence trophic interactions that bind plants and microorganisms. positive effect of elevated co( ...201223029215
Analysis of the subcellular localisation of lipoxygenase in legume and actinorhizal nodules.Plant lipoxygenases (LOXs; EC 1.13.11.12) catalyse the oxygenation of polyunsaturated fatty acids, linoleic (18:2) and a-linolenic acid (18:3(n-3)) and are involved in processes such as stress responses and development. Depending on the regio-specificity of a LOX, the incorporation of molecular oxygen leads to formation of 9- or 13-fatty acid hydroperoxides, which are used by LOX itself as well as by members of at least six different enzyme families to form a series of biologically active molecu ...201221973171
phoma medicaginis stimulates the induction of the octadecanoid and phenylpropanoid pathways in medicago truncatula.gene expression changes and metabolite abundances were measured during the interaction of medicago truncatula with the fungal necrotrophic pathogen phoma medicaginis in leaf tissue of susceptible and resistant accessions. over 330 genes were differentially expressed in plants infected with p. medicaginis relative to mock-inoculated plants at 12 h post-inoculation. of these, 191 were induced in either the resistant or the susceptible accession, with 143 genes repressed. expression changes were ob ...201222212347
movement of fluorescent dyes lucifer yellow (lych) and carboxyfluorescein (cf) in medicago truncatula gaertn. roots and root nodules.lucifer yellow (lych) and carboxyfluorescein (cf) served in medicago truncatula roots and root nodules as the markers of apoplastic and symplastic transport, respectively. the aim of this study was to understand better the water and photoassimilate translocation pathways to and within nodules. the present study shows that in damaged roots lych moves apoplastically through the vascular elements but it was not detected within the nodule vascular bundles. in intact roots, the outer cortex was stron ...201223482425
allelic differences in medicago truncatula nip/latd mutants correlate with their encoded proteins' transport activities in planta.medicago truncatula nip/latd gene, required for symbiotic nitrogen fixing nodule and root architecture development, encodes a member of the nrt1(ptr) family that demonstrates high-affinity nitrate transport in xenopus laevis oocytes. of three mtnip/latd mutant proteins, one retains high-affinity nitrate transport in oocytes, while the other two are nitrate-transport defective. to further examine the mutant proteins' transport properties, the missense mtnip/latd alleles were expressed in arabidop ...201223154505
nodule root and cochleata maintain nodule development and are legume orthologs of arabidopsis blade-on-petiole genes.during their symbiotic interaction with rhizobia, legume plants develop symbiosis-specific organs on their roots, called nodules, that house nitrogen-fixing bacteria. the molecular mechanisms governing the identity and maintenance of these organs are unknown. using medicago truncatula nodule root (noot) mutants and pea (pisum sativum) cochleata (coch) mutants, which are characterized by the abnormal development of roots from the nodule, we identified the noot and coch genes as being necessary fo ...201223136374
two direct targets of cytokinin signaling regulate symbiotic nodulation in medicago truncatula.cytokinin regulates many aspects of plant development, and in legume crops, this phytohormone is necessary and sufficient for symbiotic nodule organogenesis, allowing them to fix atmospheric nitrogen. to identify direct links between cytokinins and nodule organogenesis, we determined a consensus sequence bound in vitro by a transcription factor (tf) acting in cytokinin signaling, the nodule-enhanced medicago truncatula mt rr1 response regulator (rr). among genes rapidly regulated by cytokinins a ...201223023168
functional assessment of the medicago truncatula nip/latd protein demonstrates that it is a high-affinity nitrate transporter.the medicago truncatula nip/latd (for numerous infections and polyphenolics/lateral root-organ defective) gene encodes a protein found in a clade of nitrate transporters within the large nrt1(ptr) family that also encodes transporters of dipeptides and tripeptides, dicarboxylates, auxin, and abscisic acid. of the nrt1(ptr) members known to transport nitrate, most are low-affinity transporters. here, we show that m. truncatula nip/latd mutants are more defective in their lateral root responses to ...201222858636
the recent evolution of a symbiotic ion channel in the legume family altered ion conductance and improved functionality in calcium signaling.arbuscular mycorrhiza and the rhizobia-legume symbiosis are two major root endosymbioses that facilitate plant nutrition. in lotus japonicus, two symbiotic cation channels, castor and pollux, are indispensable for the induction of nuclear calcium spiking, one of the earliest plant responses to symbiotic partner recognition. during recent evolution, a single amino acid substitution in does not make infections1 (dmi1), the pollux putative ortholog in the closely related medicago truncatula, render ...201222706284
rapid phosphoproteomic and transcriptomic changes in the rhizobia-legume symbiosis.symbiotic associations between legumes and rhizobia usually commence with the perception of bacterial lipochitooligosaccharides, known as nod factors (nf), which triggers rapid cellular and molecular responses in host plants. we report here deep untargeted tandem mass spectrometry-based measurements of rapid nf-induced changes in the phosphorylation status of 13,506 phosphosites in 7739 proteins from the model legume medicago truncatula. to place these phosphorylation changes within a biological ...201222683509
wuschel-related homeobox5 gene expression and interaction of cle peptides with components of the systemic control add two pieces to the puzzle of autoregulation of nodulation.in legumes, the symbiotic nodules are formed as a result of dedifferentiation and reactivation of cortical root cells. a shoot-acting receptor complex, similar to the arabidopsis (arabidopsis thaliana) clavata1 (clv1)/clv2 receptor, regulating development of the shoot apical meristem, is involved in autoregulation of nodulation (aon), a mechanism that systemically controls nodule number. the targets of clv1/clv2 in the shoot apical meristem, the wuschel (wus)-related homeobox (wox) family transc ...201222232385
mtpar myb transcription factor acts as an on switch for proanthocyanidin biosynthesis in medicago truncatula.mtpar (medicago truncatula proanthocyanidin regulator) is an myb family transcription factor that functions as a key regulator of proanthocyanidin (pa) biosynthesis in the model legume medicago truncatula. mtpar expression is confined to the seed coat, the site of pa accumulation. loss-of-function par mutants contained substantially less pa in the seed coat than the wild type, whereas levels of anthocyanin and other specialized metabolites were normal in the mutants. in contrast, massive accumul ...201222307644
the non-specific lipid transfer protein n5 of medicago truncatula is implicated in epidermal stages of rhizobium-host interaction.the symbiotic interaction between leguminous plants and rhizobia involves two processes: bacterial infection, resulting in the penetration of bacteria in epidermal and cortical cells, and root nodule organogenesis. root nodule symbiosis is activated by rhizobial signalling molecules, called nodulation factors (nfs). nf perception induces the expression of several genes called early nodulins. the early nodulin n5 of medicago truncatula is a lipid transfer protein that has been shown to positively ...201223217154
cell autonomous and non-cell autonomous control of rhizobial and mycorrhizal infection in medicago truncatula.legumes can form a nitrogen fixing symbiosis with soil bacteria called rhizobia (the rl symbiosis). they can also, like most plants, form symbiotic associations with arbuscular mycorrhizal (am) fungi, which facilitate plants' phosphate nutrition. in both interactions, the symbionts are hosted inside the plant root. nitrogen-fixing rhizobia are housed in intracellular symbiotic structures within nodules, while am fungi form intracellular symbiotic structures, called arbuscules, within cortical ro ...201223221781
one-step agrobacterium mediated transformation of eight genes essential for rhizobium symbiotic signaling using the novel binary vector system phuge.advancement in plant research is becoming impaired by the fact that the transfer of multiple genes is difficult to achieve. here we present a new binary vector for agrobacterium tumefaciens mediated transformation, phuge-red, in concert with a cloning strategy suited for the transfer of up to nine genes at once. this vector enables modular cloning of large dna fragments by employing gateway technology and contains dsred1 as visual selection marker. furthermore, an r/rs inducible recombination sy ...201223112864
the small gtpase rop6 interacts with nfr5 and is involved in nodule formation in lotus japonicus.nod factor receptor5 (nfr5) is an atypical receptor-like kinase, having no activation loop in the protein kinase domain. it forms a heterodimer with nfr1 and is required for the early plant responses to rhizobium infection. a rho-like small gtpase from lotus japonicus was identified as an nfr5-interacting protein. the amino acid sequence of this rho-like gtpase is closest to the arabidopsis (arabidopsis thaliana) rop6 and medicago truncatula rop6 and was designated as ljrop6. the interaction bet ...201222434040
characterization of an isoflavonoid-specific prenyltransferase from lupinus albus.prenylated flavonoids and isoflavonoids possess antimicrobial activity against fungal pathogens of plants. however, only a few plant flavonoid and isoflavonoid prenyltransferase genes have been identified to date. in this study, an isoflavonoid prenyltransferase gene, designated as lapt1, was identified from white lupin (lupinus albus). the deduced protein sequence of lapt1 shared high homologies with known flavonoid and isoflavonoid prenyltransferases. the lapt1 gene was mainly expressed in roo ...201222430842
medicago truncatula ern transcription factors: regulatory interplay with nsp1/nsp2 gras factors and expression dynamics throughout rhizobial infection.rhizobial nodulation factors (nfs) activate a specific signaling pathway in medicago truncatula root hairs that involves the complex interplay of nodulation signaling pathway1 (nsp1)/nsp2 gras and ethylene response factor required for nodulation1 (ern1) transcription factors (tfs) to achieve full enod11 transcription. ern1 acts as a direct transcriptional regulator of enod11 through the activation of the nf-responsive "nf box." here, we show that nsp1, when combined with nsp2, can act as a stron ...201223077241
polar localization of a symbiosis-specific phosphate transporter is mediated by a transient reorientation of secretion.the arbuscular mycorrhizal (am) symbiosis, formed by land plants and am fungi, evolved an estimated 400 million years ago and has been maintained in angiosperms, gymnosperms, pteridophytes, and some bryophytes as a strategy for enhancing phosphate acquisition. during am symbiosis, the am fungus colonizes the root cortical cells where it forms branched hyphae called arbuscules that function in nutrient exchange with the plant. each arbuscule is enveloped in a plant membrane, the periarbuscular me ...201222355114
functional domain analysis of the remorin protein ljsymrem1 in lotus japonicus.in legumes rhizobial infection during root nodule symbiosis (rns) is controlled by a conserved set of receptor proteins and downstream components. mtsymrem1, a protein of the remorin family in medicago truncatula, was shown to interact with at least three receptor-like kinases (rlks) that are essential for rns. remorins are comprised of a conserved c-terminal domain and a variable n-terminal region that defines the six different remorin groups. while both n- and c-terminal regions of remorins be ...201222292047
multiple domains in mtenod8 protein including the signal peptide target it to the symbiosome.symbiotic nitrogen fixation occurs in nodules, specialized organs on the roots of legumes. within nodules, host plant cells are infected with rhizobia that are encapsulated by a plant-derived membrane forming a novel organelle, the symbiosome. in medicago truncatula, the symbiosome consists of the symbiosome membrane, a single rhizobium, and the soluble space between them, called the symbiosome space. the symbiosome space is enriched with plant-derived proteins, including the m. truncatula early ...201222415512
promex - a mass spectral reference database for plant proteomics.the promex database is one of the main collection of annotated tryptic peptides in plant proteomics. the main objective of the promex database is to provide experimental ms/ms-based information for cell type-specific or sub-cellular proteomes in arabidopsis thaliana, medicago truncatula, chlamydomonas reinhardtii, lotus japonicus, lotus corniculatus, phaseolus vulgaris, lycopersicon esculentum, solanum tuberosum, nicotiana tabacum, glycine max, zea mays, bradyrhizobium japonicum, and sinorhizobi ...201222685450
silencing of the rac1 gtpase mtrop9 in medicago truncatula stimulates early mycorrhizal and oomycete root colonizations but negatively affects rhizobial infection.rac/rop proteins (ρ-related gtpases of plants) are plant-specific small g proteins that function as molecular switches within elementary signal transduction pathways, including the regulation of reactive oxygen species (ros) generation during early microbial infection via the activation of nadph oxidase homologs of plants termed rboh (for respiratory burst oxidase homolog). we investigated the role of medicago truncatula jemalong a17 small gtpase mtrop9, orthologous to medicago sativa rac1, via ...201222399646
comparative evolution of photosynthetic genes in response to polyploid and nonpolyploid duplication.the likelihood of duplicate gene retention following polyploidy varies by functional properties (e.g. gene ontologies or protein family domains), but little is known about the effects of whole-genome duplication on gene networks related by a common physiological process. here, we examined the effects of both polyploid and nonpolyploid duplications on genes encoding the major functional groups of photosynthesis (photosystem i, photosystem ii, the light-harvesting complex, and the calvin cycle) in ...201121289102
mtbhlh1, a bhlh transcription factor involved in medicago truncatula nodule vascular patterning and nodule to plant metabolic exchanges.this study aimed at defining the role of a basic helix-loop-helix (bhlh) transcription factor gene from medicago truncatula, mtbhlh1, whose expression is upregulated during the development of root nodules produced upon infection by rhizobia bacteria. we used mtbhlh1 promoter::gus fusions and quantitative reverse-transcription polymerase chain reaction analyses to finely characterize the mtbhlh1 expression pattern. we altered mtbhlh1 function by expressing a dominantly repressed construct (cres-t ...201121679315
laser microdissection unravels cell-type-specific transcription in arbuscular mycorrhizal roots, including caat-box transcription factor gene expression correlating with fungal contact and spread.arbuscular mycorrhizae (am) are the most widespread symbioses on earth, promoting nutrient supply of most terrestrial plant species. to unravel gene expression in defined stages of medicago truncatula root colonization by am fungi, we here combined genome-wide transcriptome profiling based on whole mycorrhizal roots with real-time reverse transcription-pcr experiments that relied on characteristic cell types obtained via laser microdissection. our genome-wide approach delivered a core set of 512 ...201122034628
transcriptional profiling of medicago truncatula under salt stress identified a novel cbf transcription factor mtcbf4 that plays an important role in abiotic stress responses.salt stress hinders the growth of plants and reduces crop production worldwide. however, different plant species might possess different adaptive mechanisms to mitigate salt stress. we conducted a detailed pathway analysis of transcriptional dynamics in the roots of medicago truncatula seedlings under salt stress and selected a transcription factor gene, mtcbf4, for experimental validation.201121718548
the root determined nodulation1 gene regulates nodule number in roots of medicago truncatula and defines a highly conserved, uncharacterized plant gene family.the formation of nitrogen-fixing nodules in legumes is tightly controlled by a long-distance signaling system in which nodulating roots signal to shoot tissues to suppress further nodulation. a screen for supernodulating medicago truncatula mutants defective in this regulatory behavior yielded loss-of-function alleles of a gene designated root determined nodulation1 (rdn1). grafting experiments demonstrated that rdn1 regulatory function occurs in the roots, not the shoots, and is essential for n ...201121742814
lc/ms profiling of flavonoid glycoconjugates isolated from hairy roots, suspension root cell cultures and seedling roots of medicago truncatula.hairy roots and suspension cell cultures are commonly used in deciphering different problems related to the biochemistry and physiology of plant secondary metabolites. here, we address about the issue of possible differences in the profiles of flavonoid compounds and their glycoconjugates derived from various plant materials grown in a standard culture media. we compared profiles of flavonoids isolated from seedling roots, hairy roots, and suspension root cell cultures of a model legume plant, m ...201122039365
medicago truncatula cyp716a12 is a multifunctional oxidase involved in the biosynthesis of hemolytic saponins.saponins, a group of glycosidic compounds present in several plant species, have aglycone moieties that are formed using triterpenoid or steroidal skeletons. in spite of their importance as antimicrobial compounds and their possible benefits for human health, knowledge of the genetic control of saponin biosynthesis is still poorly understood. in the medicago genus, the hemolytic activity of saponins is related to the nature of their aglycone moieties. we have identified a cytochrome p450 gene (c ...201121821776
expression of coordinately regulated defence response genes and analysis of their role in disease resistance in medicago truncatula.microarray technology was used to identify the genes associated with disease defence responses in the model legume medicago truncatula. transcript profiles from m. truncatula cv. jemalong genotype a17 leaves inoculated with colletotrichum trifolii and erysiphe pisi and roots infected with phytophthora medicaginis were compared to identify the genes expressed in response to all three pathogens and genes unique to an interaction. the a17 genotype is resistant to c. trifolii and e. pisi, exhibiting ...201121726379
glutamine synthetase is a molecular target of nitric oxide in root nodules of medicago truncatula and is regulated by tyrosine nitration.nitric oxide (no) is emerging as an important regulatory player in the rhizobium-legume symbiosis, but its biological role in nodule functioning is still far from being understood. to unravel the signal transduction cascade and ultimately no function, it is necessary to identify its molecular targets. this study provides evidence that glutamine synthetase (gs), a key enzyme for root nodule metabolism, is a molecular target of no in root nodules of medicago truncatula, being regulated by tyrosine ...201121914816
A phylogenetic strategy based on a legume-specific whole genome duplication yields symbiotic cytokinin type-a response regulators.Legumes host their Rhizobium spp. symbiont in novel root organs called nodules. Nodules originate from differentiated root cortical cells that dedifferentiate and subsequently form nodule primordia, a process controlled by cytokinin. A whole-genome duplication has occurred at the root of the legume Papilionoideae subfamily. We hypothesize that gene pairs originating from this duplication event and are conserved in distinct Papilionoideae lineages have evolved symbiotic functions. A phylogenetic ...201122034625
transcription reprogramming during root nodule development in medicago truncatula.many genes which are associated with root nodule development and activity in the model legume medicago truncatula have been described. however information on precise stages of activation of these genes and their corresponding transcriptional regulators is often lacking. whether these regulators are shared with other plant developmental programs also remains an open question. here detailed microarray analyses have been used to study the transcriptome of root nodules induced by either wild type or ...201121304580
stars and symbiosis: microrna- and microrna*-mediated transcript cleavage involved in arbuscular mycorrhizal symbiosis.the majority of plants are able to form the arbuscular mycorrhizal (am) symbiosis in association with am fungi. during symbiosis development, plant cells undergo a complex reprogramming resulting in profound morphological and physiological changes. micrornas (mirnas) are important components of the regulatory network of plant cells. to unravel the impact of mirnas and mirna-mediated mrna cleavage on root cell reprogramming during am symbiosis, we carried out high-throughput (illumina) sequencing ...201121571671
CYP716A Subfamily Members are Multifunctional Oxidases in Triterpenoid Biosynthesis.Triterpenoids are a diverse group of secondary metabolites that are associated with a variety of biological activities. Oleanolic acid, ursolic acid and betulinic acid are common triterpenoids in plants with diverse biological activities, including antifungal, antibacterial, anti-human immunodeficiency virus (HIV) and/or antitumor activities. In the present study, using the gene co-expression analysis tool of Medicago truncatula, we found a strong correlation between CYP716A12 and ß-amyrin synth ...201122039103
identification and characterization of thioredoxin h isoforms differentially expressed in germinating seeds of the model legume medicago truncatula.thioredoxins (trxs) h, small disulfide reductases, and nadp-thioredoxin reductases (ntrs) have been shown to accumulate in seeds of different plant species and play important roles in seed physiology. however, little is known about the identity, properties, and subcellular location of trx h isoforms that are abundant in legume seeds. to fill this gap, in this work, we characterized the trx h family of medicago truncatula, a model legume, and then explored the activity and localization of trx h i ...201121239621
expression analysis of clavata1-like and nodulin21-like genes from pinus sylvestris during ectomycorrhiza formation.the ecology and physiology of ectomycorrhizal (ecm) symbiosis with conifer trees are well documented. in comparison, however, very little is known about the molecular regulation of these associations. in an earlier study, we identified three ecm-regulated pinus expressed sequence tags (est), two of which were identified as homologous to the medicago truncatula nodulin mtn21. the third est was a homologue to the receptor-like kinase clavata1. we have characterized the expression patterns of these ...201121751039
the exudate from an arbuscular mycorrhizal fungus induces nitric oxide accumulation in medicago truncatula roots.nitric oxide (no) is a signaling molecule involved in plant responses to abiotic and biotic stresses. while there is evidence for no accumulation during legume nodulation, almost no information exists for arbuscular mycorrhizas (am). here, we investigated the occurrence of no in the early stages of medicago truncatula-gigaspora margarita interaction, focusing on the plant response to fungal diffusible molecules. no was visualized in root organ cultures and seedlings by confocal microscopy using ...201121744141
symbiotic rhizobia bacteria trigger a change in localization and dynamics of the medicago truncatula receptor kinase lyk3.to form nitrogen-fixing symbioses, legume plants recognize a bacterial signal, nod factor (nf). the legume medicago truncatula has two predicted nf receptors that direct separate downstream responses to its symbiont sinorhizobium meliloti. nod factor perception encodes a putative low-stringency receptor that is responsible for calcium spiking and transcriptional responses. lysin motif receptor-like kinase3 (lyk3) encodes a putative high-stringency receptor that mediates bacterial infection. we l ...201121742993
medicago truncatula ipd3 is a member of the common symbiotic signaling pathway required for rhizobial and mycorrhizal symbioses.legumes form endosymbiotic associations with nitrogen fixing bacteria and arbuscular mycorrhizal (am) fungi which facilitate nutrient uptake. both symbiotic interactions require a molecular signal exchange between the plant and the symbiont and this involves a conserved symbiosis (sym) signaling pathway. in order to identify plant genes required for intracellular accommodation of nitrogen-fixing bacteria and am fungi, we characterized medicago truncatula symbiotic mutants defective for rhizobial ...201121692638
pseudonodule formation by wild type and symbiotic mutant medicago truncatula in response to auxin transport inhibitors.rhizobium and allied bacteria form symbiotic nitrogen fixing nodules on legume roots. plant hormones play key roles in nodule formation. we treated medicago truncatula roots with auxin transport inhibitors (atis) n-(1-naphthyl)phthalamic acid (npa) and 2,3,5-triiodobenzoic acid (tiba), to induce the formation of pseudonodules. m. truncatula mutants defective for rhizobial nod factor signal transduction still formed pseudonodules in response to atis. however, a m. truncatula ethylene-insensitive ...201121809981
immature seeds and embryos of medicago truncatula cultured in vitro.legumes are an important source of proteins and lipids for food and feed. in addition, they are -environmentally friendly because of their capacity to fix nitrogen through a symbiosis with rhizobium that permits them to produce abundant proteins even in the absence of nitrogen fertilization. seed development in plants follows three chronological steps (1) seed coat differentiation, embryo morphogenesis and endosperm development; (2) embryo maturation with storage accumulation and (3) dehydration ...201121207260
Regulation of Compound Leaf Development in Medicago truncatula by Fused Compound Leaf1, a Class M KNOX Gene.Medicago truncatula is a legume species belonging to the inverted repeat lacking clade (IRLC) with trifoliolate compound leaves. However, the regulatory mechanisms underlying development of trifoliolate leaves in legumes remain largely unknown. Here, we report isolation and characterization of fused compound leaf1 (fcl1) mutants of M. truncatula. Phenotypic analysis suggests that FCL1 plays a positive role in boundary separation and proximal-distal axis development of compound leaves. Map-based ...201122080596
in medicago truncatula, water deficit modulates the transcript accumulation of components of small rna pathways.small rnas (srnas) are 20-24 nucleotide (nt) rnas and are involved in plant development and response to abiotic stresses. plants have several srna pathways implicated in the transcriptional and post-transcriptional silencing of gene expression. two key enzyme families common to all pathways are the dicer-like (dcl) proteins involved in srnas maturation and the argonautes (agos) involved in the targeting and functional action of srnas. post-transcriptional silencing mediated by agos may occur by ...201121569262
leveraging genomic resources of model species for the assessment of diversity and phylogeny in wild and domesticated lentil.advances in comparative genomics have provided significant opportunities for analysis of genetic diversity in species with limited genomic resources, such as the genus lens. medicago truncatula expressed sequence tags (ests) were aligned with the arabidopsis thaliana genome sequence to identify conserved exon sequences and splice sites in the ests. conserved primers (cps) based on m. truncatula est sequences flanking one or more introns were then designed. a total of 22% of the cps produced poly ...201121454287
nitric oxide is required for an optimal establishment of the medicago truncatula-sinorhizobium meliloti symbiosis.nitric oxide (no) is a gaseous molecule that participates in numerous plant signalling pathways. it is involved in plant responses to pathogens and development processes such as seed germination, flowering and stomatal closure. using a permeable no-specific fluorescent probe and a bacterial reporter strain expressing the lacz gene under the control of a no-responsive promoter, we detected no production in the first steps, during infection threads growth, of the medicago truncatula-sinorhizobium ...201121457261
structure-function similarities between a plant receptor-like kinase and the human interleukin-1 receptor-associated kinase-4.phylogenetic analysis has previously shown that plant receptor-like kinases (rlks) are monophyletic with respect to the kinase domain and share an evolutionary origin with the animal interleukin-1 receptor-associated kinase/pelle-soluble kinases. the lysin motif domain-containing receptor-like kinase-3 (lyk3) of the legume medicago truncatula shows 33% amino acid sequence identity with human irak-4 over the kinase domain. using the structure of this animal kinase as a template, homology modeling ...201121205819
protection of sinorhizobium against host cysteine-rich antimicrobial peptides is critical for symbiosis.sinorhizobium meliloti differentiates into persisting, nitrogen-fixing bacteroids within root nodules of the legume medicago truncatula. nodule-specific cysteine-rich antimicrobial peptides (ncr amps) and the bacterial baca protein are essential for bacteroid development. however, the bacterial factors central to the ncr amp response and the in planta role of baca are unknown. we investigated the hypothesis that baca is critical for the bacterial response towards ncr amps. we found that baca was ...201121990963
molecular adaptation in flowering and symbiotic recognition pathways: insights from patterns of polymorphism in the legume medicago truncatula.abstract: background: we studied patterns of molecular adaptation in the wild mediterranean legume medicago truncatula. we focused on two phenotypic traits that are not functionally linked: flowering time and perception of symbiotic microbes. phenology is an important fitness component, especially for annual plants, and many instances of molecular adaptation have been reported for genes involved in flowering pathways. while perception of symbiotic microbes is also integral to adaptation in many ...201121806823
symbiont identity matters: carbon and phosphorus fluxes between medicago truncatula and different arbuscular mycorrhizal fungi.many studies have scrutinized the nutritional benefits of arbuscular mycorrhizal associations to their host plants, while the carbon (c) balance of the symbiosis has often been neglected. here, we present quantification of both the c costs and the phosphorus (p) uptake benefits of mycorrhizal association between barrel medic (medicago truncatula) and three arbuscular mycorrhizal fungal species, namely glomus intraradices, glomus claroideum, and gigaspora margarita. plant growth, p uptake and c a ...201121472448
generation of composite plants in medicago truncatula used for nodulation assays.similar to agrobacterium tumerfaciens, agrobacterium rhizogenes can transfer foreign dnas into plant cells based on the autonomous root-inducing (ri) plasmid. a. rhizogenes can cause hairy root formation on plant tissues and form composite plants after transformation. on these composite plants, some of the regenerated roots are transgenic, carrying the wild type t-dna and the engineered binary vector; while the shoots are still non-transgenic, serving to provide energy and growth support. these ...201121490571
genic snp markers and legume synteny reveal candidate genes underlying qtl for macrophomina phaseolina resistance and maturity in cowpea [vigna unguiculata (l) walp.].macrophomina phaseolina is an emerging and devastating fungal pathogen that causes significant losses in crop production under high temperatures and drought stress. an increasing number of disease incidence reports highlight the wide prevalence of the pathogen around the world and its contribution toward crop yield suppression. in cowpea [vigna unguiculata (l) walp.], limited sources of low-level host resistance have been identified, the genetic basis of which is unknown. in this study we report ...201121208448
identification of legume ropgef gene families and characterization of a medicago truncatula ropgef mediating polar growth of root hairs.root hairs play important roles in the interaction of plants with their environment. root hairs anchor the plant in the soil, facilitate nutrient uptake from the rhizosphere, and participate in symbiotic plant-microbe interactions. these specialized cells grow in a polar fashion which gives rise to their elongated shape, a process mediated in part by a family of small gtpases known as rops. ropgefs (gef, guanine nucleotide exchange factor) activate rops to effect tip growth in arabidopsis pollen ...201121223388
crosstalk between the nodulation signaling pathway and the autoregulation of nodulation in medicago truncatula.• a subset of clavata3/endosperm-surrounding region-related (cle) peptides are involved in autoregulation of nodulation (aon) in medicago truncatula (e.g. mtcle12 and mtcle13). however, their linkage to other components of the aon pathways downstream of the shoot-derived inhibitor (sdi) is not understood. • we have ectopically expressed the putative peptide ligand encoding genes mtcle12 and mtcle13 in m. truncatula which abolished nodulation completely in wild-type roots but not in the supernodu ...201121507004
transformed hairy roots of discaria trinervis: a valuable tool for studying actinorhizal symbiosis in the context of intercellular infection.among infection mechanisms leading to root nodule symbiosis, the intercellular infection pathway is probably the most ancestral but also one of the least characterized. intercellular infection has been described in discaria trinervis, an actinorhizal plant belonging to the rosales order. to decipher the molecular mechanisms underlying intercellular infection with frankia, we set up an efficient genetic transformation protocol for d. trinervis based on a. rhizogenes. we showed that composite plan ...201121585269
transcriptome sequencing of lentil based on second-generation technology permits large-scale unigene assembly and ssr marker discovery.abstract: background: lentil (lens culinaris medik.) is a cool-season grain legume which provides a rich source of protein for human consumption. in terms of genomic resources, lentil is relatively underdeveloped, in comparison to other fabaceae species, with limited available data. there is hence a significant need to enhance such resources in order to identify novel genes and alleles for molecular breeding to increase crop productivity and quality. results: tissue-specific cdna samples from si ...201121609489
harvest-inducibility of the promoter of alfalfa s-adenosyl-l: -methionine: trans-caffeoyl-coa3-o-methyltransferase gene.a major limitation on the expression of some foreign proteins in transgenic plants is the toxic effect of such proteins on the host plant resulting in inhibition of normal growth and development. a solution to this problem is to control the expression of genes for such proteins by means of inducible promoters, as is frequently done in microbial systems. a cdna clone was obtained from subtractive hybridization of non-harvested and harvested alfalfa leaf tissue, named hi12. the hi12 cdna was ident ...201121667113
identification and characterisation of seed storage protein transcripts from lupinus angustifolius.in legumes, seed storage proteins are important for the developing seedling and are an important source of protein for humans and animals. lupinus angustifolius (l.), also known as narrow-leaf lupin (nll) is a grain legume crop that is gaining recognition as a potential human health food as the grain is high in protein and dietary fibre, gluten-free and low in fat and starch.201121457583
mate2 mediates vacuolar sequestration of flavonoid glycosides and glycoside malonates in medicago truncatula.the majority of flavonoids, such as anthocyanins, proanthocyanidins, and isoflavones, are stored in the central vacuole, but the molecular basis of flavonoid transport is still poorly understood. here, we report the functional characterization of a multidrug and toxin extrusion transporter (mate2), from medicago truncatula. mate 2 is expressed primarily in leaves and flowers. despite its high similarity to the epicatechin 3'-o-glucoside transporter mate1, mate2 cannot efficiently transport proan ...201121467581
STENOFOLIA Regulates Blade Outgrowth and Leaf Vascular Patterning in Medicago truncatula and Nicotiana sylvestris.Dicot leaf primordia initiate at the flanks of the shoot apical meristem and extend laterally by cell division and cell expansion to form the flat lamina, but the molecular mechanism of lamina outgrowth remains unclear. Here, we report the identification of STENOFOLIA (STF), a WUSCHEL-like homeobox transcriptional regulator, in Medicago truncatula, which is required for blade outgrowth and leaf vascular patterning. STF belongs to the MAEWEST clade and its inactivation by the transposable element ...201121719692
strigolactone biosynthesis in medicago truncatula and rice requires the symbiotic gras-type transcription factors nsp1 and nsp2.legume gras (gai, rga, scr)-type transcription factors nodulation signaling pathway1 (nsp1) and nsp2 are essential for rhizobium nod factor-induced nodulation. both proteins are considered to be nod factor response factors regulating gene expression after symbiotic signaling. however, legume nsp1 and nsp2 can be functionally replaced by nonlegume orthologs, including rice (oryza sativa) nsp1 and nsp2, indicating that both proteins are functionally conserved in higher plants. here, we show that n ...201122039214
Recent Progress in Development of Tnt1 Functional Genomics Platform for Medicago truncatula and Lotus japonicus in Bulgaria.Legumes, as protein-rich crops, are widely used for human food, animal feed and vegetable oil production. Over the past decade, two legume species, Medicago truncatula and Lotus japonicus, have been adopted as model legumes for genomics and physiological studies. The tobacco transposable element, Tnt1, is a powerful tool for insertional mutagenesis and gene inactivation in plants. A large collection of Tnt1-tagged lines of M. truncatula cv. Jemalong was generated during the course of the project ...201121966253
reverse genetics in medicago truncatula using tnt1 insertion mutants.medicago truncatula has been chosen as one of the two model species for legume molecular genetics and functional genomics studies. with the imminent completion of m. truncatula genome sequencing, availability of large-scale mutant populations becomes a priority. over the last 5 years, nearly 12,000 insertion lines, which represent approximately 300,000 insertions, have been generated at the samuel roberts noble foundation using the tobacco retrotransposon tnt1. individual genomic dna was isolate ...201120931380
contribution of nfp lysm domains to the recognition of nod factors during the medicago truncatula/sinorhizobium meliloti symbiosis.the root nodule nitrogen fixing symbiosis between legume plants and soil bacteria called rhizobia is of great agronomical and ecological interest since it provides the plant with fixed atmospheric nitrogen. the establishment of this symbiosis is mediated by the recognition by the host plant of lipo-chitooligosaccharides called nod factors (nfs), produced by the rhizobia. this recognition is highly specific, as precise nf structures are required depending on the host plant. here, we study the imp ...201122087221
from model to crop: functional analysis of a stay-green gene in the model legume medicago truncatula and effective use of the gene for alfalfa improvement.medicago truncatula has been developed into a model legume. its close relative alfalfa (medicago sativa) is the most widely grown forage legume crop in the united states. by screening a large population of m. truncatula mutants tagged with the transposable element of tobacco (nicotiana tabacum) cell type1 (tnt1), we identified a mutant line (nf2089) that maintained green leaves and showed green anthers, central carpels, mature pods, and seeds during senescence. genetic and molecular analyses rev ...201121957014
phosphorous deficiency decreases nitrogenase activity but increases proton efflux in n2-fixing medicago truncatula.effects of sinorhizobium strain and p nutrition on n(2)-dependent growth, nitrogenase activity and proton efflux by nodulated roots were investigated in the model legume medicago truncatula cultivar jemalong grown in hydroaeroponic culture in symbioses with sinorhizobium meliloti strains 102f51 and 2011. sinorhizobium strain had strong effects on nitrogenase activity and n(2)-dependent growth, with s. meliloti 102f51 being the more efficient strain. apparent and total nitrogenase activities, mea ...201121334214
Triterpene Functional Genomics in Licorice for Identification of CYP72A154 Involved in the Biosynthesis of Glycyrrhizin.Glycyrrhizin, a triterpenoid saponin derived from the underground parts of Glycyrrhiza plants (licorice), has several pharmacological activities and is also used worldwide as a natural sweetener. The biosynthesis of glycyrrhizin involves the initial cyclization of 2,3-oxidosqualene to the triterpene skeleton ß-amyrin, followed by a series of oxidative reactions at positions C-11 and C-30, and glycosyl transfers to the C-3 hydroxyl group. We previously reported the identification of a cytochrome ...201122128119
interactions of arabidopsis and m. truncatula with the same pathogens differ in dependence on ethylene and ethylene response factors.microbial pathogens inflict large losses to agriculture annually and thus mechanisms of plant resistance and how to deploy them to enhance disease resistance in crops are foci of much research interest. we recently described the important role of ethylene and ethylene response transcription factors (erfs), particularly mterf1-1, in mediating resistance to the fungal pathogen rhizoctonia solani in the model legume, medicago truncatula. previous studies on the closely related aterf14, a master reg ...201121389781
fluorescent pseudomonads harboring type iii secretion genes are enriched in the mycorrhizosphere of medicago truncatula.type iii secretion systems (t3sss) of gram-negative bacteria mediate direct interactions with eukaryotic cells. pseudomonas spp. harboring t3ss genes (t3ss+) were previously shown to be more abundant in the rhizosphere than in bulk soil. to discriminate the contribution of roots and associated arbuscular mycorrhizal fungi (amf) on the enrichment of t3ss+ fluorescent pseudomonads in the rhizosphere of medicago truncatula, their frequency was assessed among pseudomonads isolated from mycorrhizal a ...201121204867
tnt1 retrotransposon tagging of stf in medicago truncatula reveals tight coordination of metabolic, hormonal and developmental signals during leaf morphogenesis.tnt1 (transposable element if nicotiana tabaccum cell type 1) is one of the very few active ltr retrotransposons used for gene tagging in plants. in the model legume medicago truncatula, tnt1 has been effectively used as a gene knock-out tool to generate several very useful mutants. stenofolia (stf) is such a mutant identified by tnt1 insertion in a wuschel-like homeobox transcription factor. stf is required for blade outgrowth, leaf vascular patterning and female reproductive organ development ...201122545243
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 ...201120238171
biosynthesis of udp-xylose and udp-arabinose in sinorhizobium meliloti 1021: first characterization of a bacterial udp-xylose synthase, and udp-xylose 4-epimerase.sinorhizobium meliloti is a soil bacterium that fixes nitrogen after being established inside nodules that can form on the roots of several legumes, including medicago truncatula. a mutation in an s. meliloti gene (lpsb) required for lipopolysaccharide synthesis has been reported to result in defective nodulation and an increase in the synthesis of a xylose-containing glycan. glycans containing xylose as well as arabinose are also formed by other rhizobial species, but little is known about thei ...201120847005
the medicago genome provides insight into the evolution of rhizobial symbioses.legumes (fabaceae or leguminosae) are unique among cultivated plants for their ability to carry out endosymbiotic nitrogen fixation with rhizobial bacteria, a process that takes place in a specialized structure known as the nodule. legumes belong to one of the two main groups of eurosids, the fabidae, which includes most species capable of endosymbiotic nitrogen fixation. legumes comprise several evolutionary lineages derived from a common ancestor 60 million years ago (myr ago). papilionoids ar ...201122089132
exploring the genetic diversity of ethiopian grass pea (lathyrus sativus l.) using est-ssr markers.expressed sequence tags (ests) in public databases and cross-species transferable markers are considered to be a cost-effective means for developing sequence-based markers for less-studied species. in this study, est-simple sequence repeat (ssr) markers developed from lathyrus sativus l. est sequences and cross-transferable est-ssrs derived from medicago truncatula l. were utilized to investigate the genetic diversity among grass pea populations from ethiopia. a total of 45 alleles were detected ...201122924019
the rice miniature inverted repeat transposable element mping is an effective insertional mutagen in soybean.insertional mutagenesis of legume genomes such as soybean (glycine max) should aid in identifying genes responsible for key traits such as nitrogen fixation and seed quality. the relatively low throughput of soybean transformation necessitates the use of a transposon-tagging strategy where a single transformation event will produce many mutations over a number of generations. however, existing transposon-tagging tools being used in legumes are of limited utility because of restricted transpositi ...201121844309
capturing cold-stress-related sequence diversity from a wild relative of common bean (phaseolus angustissimus).one restriction to the cultivation of common bean, phaseolus vulgaris l., is its limited tolerance to low temperatures. in the present study, subtraction suppression hybridization was employed to enrich for stress responsive genes in both a chilling-susceptible common bean and a relatively more chilling-tolerant wild bean species, phaseolus angustissimus. for each species, approximately 11 000 expressed sequence tags were generated. comparative sequence analysis of the est collection with the av ...201121797793
border sequences of medicago truncatula cle36 are specifically cleaved by endoproteases common to the extracellular fluids of medicago and soybean.cle (clavata3/esr-related) peptides are developmental regulators that are secreted into the apoplast. little is known about the role of the sequences that flank cle peptides in terms of their biological activity or how they are targeted by proteases that are known to liberate the final active cle peptides from their precursor sequences. the biological activity of medicago truncatula cle36, which possesses broadly conserved border sequences flanking the putative final active cle36 peptide product ...201121633083
characterisation of the legume serk-nik gene superfamily including splice variants: implications for development and defence.somatic embryogenesis receptor-like kinase (serk) genes are part of the regulation of diverse signalling events in plants. current evidence shows serk proteins function both in developmental and defence signalling pathways, which occur in response to both peptide and steroid ligands. serks are generally present as small gene families in plants, with five serk genes in arabidopsis. knowledge gained primarily through work on arabidopsis serks indicates that these proteins probably interact with a ...201121385462
a legume specific protein database (legprot) improves the number of identified peptides, confidence scores and overall protein identification success rates for legume proteomics.a legume specific protein database (legprot) has been created containing sequences from seven legume species, i.e., glycine max, lotus japonicus, medicago sativa, medicago truncatula, lupinusalbus, phaseolus vulgaris, and pisum sativum. the database consists of amino acid sequences translated from predicted gene models and 6-frame translations of tentative consensus (tc) sequences assembled from expressed sequence tags (ests) and singleton ests. this database was queried using mass spectral data ...201121353266
developmental analysis of a medicago truncatula smooth leaf margin1 mutant reveals context-dependent effects on compound leaf development.compound leaf development requires highly regulated cell proliferation, differentiation, and expansion patterns. we identified loss-of-function alleles at the smooth leaf margin1 (slm1) locus in medicago truncatula, a model legume species with trifoliate adult leaves. slm1 encodes an auxin efflux carrier protein and is the ortholog of arabidopsis thaliana pin-formed1 (pin1). auxin distribution is impaired in the slm1 mutant, resulting in pleiotropic phenotypes in different organs. the most strik ...201121693694
evolution of the number of lrrs in plant disease resistance genes.the largest group of plant resistance (r) genes contain the regions that encode the nucleotide-binding site (nbs) and leucine-rich repeat (lrr) domains (nbs-lrr genes). to gain new resistance, amino acid substitutions and changes in number of the lrrs that recognize the presence of pathogens are considered important. in this study, we focus on the evolution of the number of lrrs and analyze the genome data of five plant species, arabidopsis thaliana, oryza sativa, medicago truncatula, lotus japo ...201121442326
plantmirnapred: efficient classification of real and pseudo plant pre-mirnas.micrornas (mirnas) are a set of short (21-24 nt) non-coding rnas that play significant roles as post-transcriptional regulators in animals and plants. while some existing methods use comparative genomic approaches to identify plant precursor mirnas (pre-mirnas), others are based on the complementarity characteristics between mirnas and their target mrnas sequences. however, they can only identify the homologous mirnas or the limited complementary mirnas. furthermore, since the plant pre-mirnas a ...201121441575
the pea gigas gene is a flowering locus t homolog necessary for graft-transmissible specification of flowering but not for responsiveness to photoperiod.garden pea (pisum sativum) was prominent in early studies investigating the genetic control of flowering and the role of mobile flowering signals. in view of recent evidence that genes in the flowering locus t (ft) family play an important role in generating mobile flowering signals, we isolated the ft gene family in pea and examined the regulation and function of its members. comparison with medicago truncatula and soybean (glycine max) provides evidence of three ancient subclades (fta, ftb, an ...201121282524
whole-genome nucleotide diversity, recombination, and linkage disequilibrium in the model legume medicago truncatula.medicago truncatula is a model for investigating legume genetics, including the genetics and evolution of legume-rhizobia symbiosis. we used whole-genome sequence data to identify and characterize sequence polymorphisms and linkage disequilibrium (ld) in a diverse collection of 26 m. truncatula accessions. our analyses reveal that m. truncatula harbors both higher diversity and less ld than soybean (glycine max) and exhibits patterns of ld and recombination similar to arabidopsis thaliana. the p ...201121949378
durable broad-spectrum powdery mildew resistance in pea er1 plants is conferred by natural loss-of-function mutations in psmlo1.loss-of-function alleles of plant-specific mlo (mildew resistance locus o) genes confer broad-spectrum powdery mildew resistance in monocot (barley) and dicot (arabidopsis thaliana, tomato) plants. recessively inherited powdery mildew resistance in pea (pisum sativum) er1 plants is, in many aspects, reminiscent of mlo-conditioned powdery mildew immunity, yet the underlying gene has remained elusive to date. we used a polymerase chain reaction (pcr)-based approach to amplify a candidate mlo cdna ...201121726385
the re-establishment of desiccation tolerance in germinated arabidopsis thaliana seeds and its associated transcriptome.the combination of robust physiological models with "omics" studies holds promise for the discovery of genes and pathways linked to how organisms deal with drying. here we used a transcriptomics approach in combination with an in vivo physiological model of re-establishment of desiccation tolerance (dt) in arabidopsis thaliana seeds. we show that the incubation of desiccation sensitive (ds) germinated arabidopsis seeds in a polyethylene glycol (peg) solution re-induces the mechanisms necessary f ...201122195004
mining functional microsatellites in legume unigenes.highly polymorphic and transferable microsatellites (ssrs) are important for comparative genomics, genome analysis and phylogenetic studies. development of novel species-specific microsatellite markers remains a costly and labor-intensive project. therefore, interest has been shifted from genomic to genic markers owing to their high inter-species transferability as they are developed from conserved coding regions of the genome. this study concentrates on comparative analysis of genic microsatell ...201122125396
a stress-associated protein containing a20/an1 zing-finger domains expressed in medicago truncatula seeds.mtsap1 (medicago truncatula stress-associated protein 1) was revealed as a down-regulated gene by suppressive subtractive hybridization between two mrna populations of embryo axes harvested before and after radicle emergence. mtsap1 is the first gene encoding a sap with a20 and an1 zinc-finger domains characterized in m. truncatula. mtsap1 protein shares 54% and 62% homology with atsap7 (arabidopsis thaliana) and osisap8 (oryza sativa) respectively, with in particular a strong homology in the a2 ...201121296585
comparative analysis of mirnas and their targets across four plant species.microrna (mirna) mediated regulation of gene expression has been recognized as a major posttranscriptional regulatory mechanism also in plants. we performed a comparative analysis of mirnas and their respective gene targets across four plant species: arabidopsis thaliana (ath), medicago truncatula(mtr), brassica napus (bna), and chlamydomonas reinhardtii (cre).201122067256
standardizing seed dormancy research.seeds are very attractive and convenient for molecular genetic studies that challenge principal biological phenomena related to the initiation and suppression of growth (e.g., germination and dormancy, respectively). the number of reports in this field is rapidly expanding. seed dormancy is a widely misinterpreted biological attribute. one of the main reasons is the general neglect of reliable dormancy assays; often, the sole criterion of current dormancy assays is the total germination of a see ...201121898248
the mitochondrial proteome of the model legume medicago truncatula.legumes carry out special biochemical functions, e.g. the fixation of molecular nitrogen based on a symbiosis with proteobacteria. at the cellular level, this symbiosis has to be implemented into the energy metabolism of the host cell. to provide a basis for future analyses, we have characterized the protein complement of mitochondria of the model legume medicago truncatula using two-dimensional isoelectric focussing (ief) and blue-native (bn)-sds-page. while the ief reference map resulted mainl ...201121893218
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