Publications

the mycorrhizal fungus gigaspora margarita possesses a cuzn superoxide dismutase that is up-regulated during symbiosis with legume hosts.	a full-length cdna showing high similarity to previously described cuzn superoxide dismutases (sods) was identified in an expressed sequence tag collection from germinated spores of the arbuscular mycorrhizal fungus gigaspora margarita (beg 34). the corresponding gene sequence, named gmarcuznsod, is composed of four exons. as revealed by heterologous complementation assays in a yeast mutant, gmarcuznsod encodes a functional polypeptide able to confer increased tolerance to oxidative stress. the ...	2005	15749992
invasion of lotus japonicus root hairless 1 by mesorhizobium loti involves the nodulation factor-dependent induction of root hairs.	in many legumes, including lotus japonicus and medicago truncatula, susceptible root hairs are the primary sites for the initial signal perception and physical contact between the host plant and the compatible nitrogen-fixing bacteria that leads to the initiation of root invasion and nodule organogenesis. however, diverse mechanisms of nodulation have been described in a variety of legume species that do not rely on root hairs. to clarify the significance of root hairs during the l. japonicus-me ...	2005	15778455
glutathione and homoglutathione play a critical role in the nodulation process of medicago truncatula.	legumes form a symbiotic interaction with bacteria of the rhizobiaceae family to produce nitrogen-fixing root nodules under nitrogen-limiting conditions. this process involves the recognition of the bacterial nod factors by the plant which mediates the entry of the bacteria into the root and nodule organogenesis. we have examined the importance of the low molecular weight thiols, glutathione (gsh) and homoglutathione (hgsh), during the nodulation process in the model legume medicago truncatula. ...	2005	15782639
grafting between model legumes demonstrates roles for roots and shoots in determining nodule type and host/rhizobia specificity.	previous grafting experiments have demonstrated that legume shoots play a critical role in symbiotic development of nitrogen-fixing root nodules by regulating nodule number. here, reciprocal grafting experiments between the model legumes lotus japonicus and medicago truncatula were carried out to investigate the role of the shoot in the host-specificity of legume-rhizobia symbiosis and nodule type. lotus japonicus is nodulated by mesorhizobium loti and makes determinate nodules, whereas m. trunc ...	2005	15824071
a kunitz trypsin inhibitor from chickpea (cicer arietinum l.) that exerts anti-metabolic effect on podborer (helicoverpa armigera) larvae.	chickpea (cicer arietinum l.) seeds contain bowman-birk proteinase inhibitors, which are ineffective against the digestive proteinases of larvae of the insect pest helicoverpa armigera. we have identified and purified a low expressing proteinase inhibitor (pi), distinct from the bowman-birk inhibitors and active against h. armigera gut proteinases (hgp), from chickpea seeds. n-terminal sequencing of this hgp inhibitor revealed a sequence similar to reported pea (pisum sativum) and chickpea alpha ...	2005	15830127
identification of a large cluster of coiled coil-nucleotide binding site--leucine rich repeat-type genes from the rps1 region containing phytophthora resistance genes in soybean.	fifteen rps genes confer resistance against the oomycete pathogen phytophthora sojae, which causes root and stem rot disease in soybean. we have isolated a disease resistance gene-like sequence from the genomic region containing rps1-k. four classes of cdna of the sequence were isolated from etiolated hypocotyl tissues that express the rps1-k-encoded phytophthora resistance. sequence analyses of a cdna clone showed that the sequence is a member of the coiled coil-nucleotide binding site-leucine ...	2005	15841357
molecular cloning and characterisation of a rab-binding gdp-dissociation inhibitor from medicago truncatula.	we have isolated and sequenced the full-length cdna of a gdp-dissociation inhibitor (gdi) from the model legume medicago truncatula l. the cdna (mtgdi) contains an open reading frame of 1335 bp, coding for a protein of 444 amino acids with a calculated molecular mass of 49,785 kda. the deduced amino acid sequence shows significant homology to other plant gdis, the highest homology being found to gdi from the legume cicer arietinum (96% identity). the mtgdi was expressed as a n-terminal flag-fusi ...	2005	15854828
accumulation of reactive oxygen species in arbuscular mycorrhizal roots.	we investigated the accumulation of reactive oxygen species (ros) in arbuscular mycorrhizal (am) roots from medicago truncatula, zea mays and nicotiana tabacum using three independent staining techniques. colonized root cortical cells and the symbiotic fungal partner were observed to be involved in the production of ros. extraradical hyphae and spores from glomus intraradices accumulated small levels of ros within their cell wall and produced ros within the cytoplasm in response to stress. withi ...	2005	15875223
insertional mutagenesis: a swiss army knife for functional genomics of medicago truncatula.	legumes are second only to grasses in worldwide economic importance, and understanding their molecular genetics is vital to the breeding of important grain and forage legumes. over the past decade, medicago truncatula has been selected as a model plant in which to study biological processes that are unique and pertinent to legumes, and that cannot easily be studied in arabidopsis. here, we discuss the most common tools for introducing and analyzing genetic mutations in m. truncatula. because tra ...	2005	15882655
nod factor signaling genes and their function in the early stages of rhizobium infection.	a lipochitosaccharide-based signal molecule that is secreted by rhizobium, named nod factor (nf), induces root nodule formation in legumes. this molecule is also essential for the establishment of bacterial infection. genetic analyses in the legume species lotus japonicus and medicago truncatula have led to the identification of many components of the nf signaling cascade. at least three of these genes do not function exclusively in the rhizobium symbiosis but are also essential for the formatio ...	2005	15955723
nodulation signaling in legumes requires nsp2, a member of the gras family of transcriptional regulators.	rhizobial bacteria enter a symbiotic interaction with legumes, activating diverse responses in roots through the lipochito oligosaccharide signaling molecule nod factor. here, we show that nsp2 from medicago truncatula encodes a gras protein essential for nod-factor signaling. nsp2 functions downstream of nod-factor-induced calcium spiking and a calcium/calmodulin-dependent protein kinase. we show that nsp2-gfp expressed from a constitutive promoter is localized to the endoplasmic reticulum/nucl ...	2005	15961668
the latd gene of medicago truncatula is required for both nodule and root development.	the evolutionary origins of legume root nodules are largely unknown. we have identified a gene, latd, of the model legume medicago truncatula, that is required for both nodule and root development, suggesting that these two developmental processes may share a common evolutionary origin. the latd mutant plants initiate nodule formation but do not complete it, resulting in immature, non-nitrogen-fixing nodules. similarly, lateral roots initiate, but remain short stumps. the primary root, which ini ...	2005	15986921
ectopic expression of the mycorrhiza-specific chitinase gene mtchit 3-3 in medicago truncatula root-organ cultures stimulates spore germination of glomalean fungi.	expression of mtchit 3-3, a class iii chitinase gene, is specifically induced by arbuscular mycorrhizal (am) fungi in roots of the model legume medicago truncatula and its transcripts accumulate in cells containing arbuscules. agrobacterium rhizogenes-transformed roots and root-organ cultures of m. truncatula were used to study effects of mtchit 3-3 on am fungi. * this work provides evidence for enzymatic activity of the mtchit 3-3 gene product and shows with promoter:gus fusions that a 2 kb fra ...	2005	15998406
formation of organelle-like n2-fixing symbiosomes in legume root nodules is controlled by dmi2.	in most legume nodules, the n2-fixing rhizobia are present as organelle-like structures inside their host cells. these structures, named symbiosomes, contain one or a few rhizobia surrounded by a plant membrane. symbiosome formation requires the release of bacteria from cell-wall-bound infection threads. in primitive legumes, rhizobia are hosted in intracellular infection threads that, in contrast to symbiosomes, are bound by a cell wall. the formation of symbiosomes is presumed to represent a m ...	2005	16006515
metabolic engineering of isoflavonoid biosynthesis in alfalfa.	the potential health benefits of dietary isoflavones have generated considerable interest in engineering the synthesis of these phytoestrogens into plants. genistein glucoside production (up to 50 nmol g(-1) fresh weight) was engineered in alfalfa (medicago sativa) leaves by constitutive expression of isoflavone synthase from medicago truncatula (mtifs1). glucosides of biochanin a (4'-o-methylgenistein) and pratensein (3'-hydroxybiochanin a) also accumulated. although mtifs1 was highly expressed ...	2005	16006598
munich information center for protein sequences plant genome resources: a framework for integrative and comparative analyses 1(w).	with several plant genomes sequenced, the power of comparative genome analysis can now be applied. however, genome-scale cross-species analyses are limited by the effort for data integration. to develop an integrated cross-species plant genome resource, we maintain comprehensive databases for model plant genomes, including arabidopsis (arabidopsis thaliana), maize (zea mays), medicago truncatula, and rice (oryza sativa). integration of data and resources is emphasized, both in house as well as w ...	2005	16010004
defensin gene family in medicago truncatula: structure, expression and induction by signal molecules.	a large gene family encoding the putative cysteine-rich defensins was discovered in medicago truncatula. sixteen members of the family were identified by screening a cloned seed defensin from m. sativa (gao et al. 2000) against the institute for genomic research's (tigr) m. truncatula gene index (mtgi version 7). based on the comparison of their amino acid sequences, m. truncatula defensins fell arbitrarily into three classes displaying extensive sequence divergence outside of the eight canonica ...	2005	16021402
soil nematodes mediate positive interactions between legume plants and rhizobium bacteria.	symbiosis between legume species and rhizobia results in the sequestration of atmospheric nitrogen into ammonium, and the early mechanisms involved in this symbiosis have become a model for plant-microbe interactions and thus highly amenable for agricultural applications. the working model for this interaction states that the symbiosis is the outcome of a chemical/molecular dialogue initiated by flavonoids produced by the roots of legumes and released into the soil as exudates, which specificall ...	2005	16025342
plants as bioreactors: a comparative study suggests that medicago truncatula is a promising production system.	plants are emerging as a promising alternative to conventional platforms for the large-scale production of recombinant proteins. this field of research, known as molecular farming, is developing rapidly and several plant-derived recombinant proteins are already in advanced clinical trials. however, the full potential of molecular farming can only be realized if we gain a fundamental understanding of biological processes regulating the production and accumulation of functional recombinant protein ...	2005	16026877
guab activity is required in rhizobium tropici during the early stages of nodulation of determinate nodules but is dispensable for the sinorhizobium meliloti-alfalfa symbiotic interaction.	the guab mutant strain rhizobium tropici ciat8999-10t is defective in symbiosis with common bean, forming nodules that lack rhizobial content. in order to investigate the timing of the guab requirement during the nodule formation on the host common bean by the strain ciat899-10.t, we constructed gene fusions in which the guab gene is expressed under the control of the symbiotic promoters noda, baca, and nifh. our data indicated that the guab is required from the early stages of nodulation becaus ...	2005	16042020
transcript enrichment of nod factor-elicited early nodulin genes in purified root hair fractions of the model legume medicago truncatula.	this article describes an efficient procedure to study nod factor-induced gene expression in root hairs of the model legume medicago truncatula. by developing an improved method of fracturing frozen root hairs, it has been possible to obtain a highly purified root hair fraction from m. truncatula seedlings yielding sufficient rna for real-time quantitative rt-pcr expression analysis. after nod factor treatment it was possible to detect up to 100-fold increases of mtenod11 and pmtenod11-gus trans ...	2005	16043451
microtubules guide root hair tip growth.	the ability to establish cell polarity is crucial to form and function of an individual cell. polarity underlies critical processes during cell development, such as cell growth, cell division, cell differentiation and cell signalling. interphase cytoplasmic microtubules in tip-growing fission yeast cells have been shown to play a particularly important role in regulating cell polarity. by placing proteins that serve as spatial cues in the cell cortex of the expanding tip, microtubules determine ...	2005	16101908
organization and metabolism of plastids and mitochondria in arbuscular mycorrhizal roots of medicago truncatula.	colonization of root cortical cells by arbuscular mycorrhizal fungi leads to marked cytological changes of plastids and mitochondria. plastids in particular are forming tubular extensions partially connecting individual organelles in a network-like way. these cytological changes correspond to an increased need for plastid and mitochondrial products during establishment and functioning of the symbiosis. the analysis of metabolite and transcript levels in mycorrhizal and nonmycorrhizal roots from ...	2005	16126866
expression of the medicago truncatula dm12 gene suggests roles of the symbiotic nodulation receptor kinase in nodules and during early nodule development.	the medicago truncatula dmi2 gene encodes a receptorlike kinase required for establishing root endosymbioses. the dmi2 gene was shown to be expressed much more highly in roots and nodules than in leaves and stems. in roots, its expression was not altered by nitrogen starvation or treatment with lipochitooligosaccharidic nod factors. moreover, the dmi2 mrna abundance in roots of the nfp, dmil, dmi3, nsp1, nsp2, and hcl symbiotic mutants was similar to the wild type, whereas lower levels in some d ...	2005	16134899
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
mtenod11 gene activation during rhizobial infection and mycorrhizal arbuscule development requires a common at-rich-containing regulatory sequence.	the mtenod11 gene from the model legume medicago truncatula is transcriptionally activated both in response to sinorhizobium meliloti nod factors and throughout infection of root tissues by the nitrogen-fixing microsymbiont. to identify the regulatory sequences involved in symbiosis-related mtenod11 expression, a series of promoter deletions driving the beta-glucuronidase reporter gene were analyzed in transgenic m. truncatula roots. these studies have revealed that distinct regulatory regions a ...	2005	16478046
characterisation of new symbiotic medicago truncatula (gaertn.) mutants, and phenotypic or genotypic complementary information on previously described mutants.	from a pool of medicago truncatula mutants--obtained by gamma-irradiation or ethyl methanesulfonate mutagenesis--impaired in symbiosis with the n-fixing bacterium sinorhizobium meliloti, new mutants are described and genetically analysed, and for already reported mutants, complementary data are given on their phenotypic and genetic analysis. phenotypic data relate to nodulation and mycorrhizal phenotypes. among the five new mutants, three were classified as [nod+ fix- myc+] and the mutations wer ...	2005	15558330
nod factors alter the microtubule cytoskeleton in medicago truncatula root hairs to allow root hair reorientation.	the microtubule (mt) cytoskeleton is an important part of the tip-growth machinery in legume root hairs. here we report the effect of nod factor (nf) on mts in root hairs of medicago truncatula. in tip-growing hairs, the ones that typically curl around rhizobia, nf caused a subtle shortening of the endoplasmic mt array, which recovered within 10 min, whereas cortical mts were not visibly affected. in growth-arresting root hairs, endoplasmic mts disappeared shortly after nf application, but refor ...	2005	16353554
aphid resistance in medicago truncatula involves antixenosis and phloem-specific, inducible antibiosis, and maps to a single locus flanked by nbs-lrr resistance gene analogs.	aphids and related insects feed from a single cell type in plants: the phloem sieve element. genetic resistance to acyrthosiphon kondoi shinji (bluegreen aphid or blue alfalfa aphid) has been identified in medicago truncatula gaert. (barrel medic) and backcrossed into susceptible cultivars. the status of m. truncatula as a model legume allows an in-depth study of defense against this aphid at physiological, biochemical, and molecular levels. in this study, two closely related resistant and susce ...	2005	15778464
comprehensive structural analysis of the genome of red clover (trifolium pratense l.).	with the aim of establishing the basic knowledge and resources needed for applied genetics, we investigated the genome structure of red clover trifolium pratense l. by a combination of cytological, genomic and genetic approaches. the deduced genome size was approximately 440 mb, as estimated by measuring the nuclear dna content by flow cytometry. seven chromosomes could be distinguished by microscopic observation of dapi stained prometaphase chromosomes and fluorescence in situ hybridization usi ...	2005	16769692
significant microsynteny with new evolutionary highlights is detected between arabidopsis and legume model plants despite the lack of macrosynteny.	the increased amount of data produced by large genome sequencing projects allows scientists to carry out important syntenic studies to a great extent. detailed genetic maps and entirely or partially sequenced genomes are compared, and macro- and microsyntenic relations can be determined for different species. in our study, the syntenic relationships between key legume plants and two model plants, arabidopsis thaliana and populus trichocarpa were investigated. the comparison of the map position o ...	2005	16273388
the dark side of green fluorescent protein.	here, severe interference of chlorophyll with green fluorescent protein (gfp) fluorescence is described for medicago (medicago truncatula), rice (oryza sativa) and arabidopsis (arabidopsis thaliana). this interference disrupts the proportional relationship between gfp content and fluorescence that is intrinsic to its use as a quantitative reporter. the involvement of chlorophyll in the loss of gfp fluorescence with leaf age was shown in vivo, by the removal of chlorophyll through etiolation or b ...	2005	16219071
highly syntenic regions in the genomes of soybean, medicago truncatula, and arabidopsis thaliana.	recent genome sequencing enables mega-base scale comparisons between related genomes. comparisons between animals, plants, fungi, and bacteria demonstrate extensive synteny tempered by rearrangements. within the legume plant family, glimpses of synteny have also been observed. characterizing syntenic relationships in legumes is important in transferring knowledge from model legumes to crops that are important sources of protein, fixed nitrogen, and health-promoting compounds.	2005	16102170
placing paleopolyploidy in relation to taxon divergence: a phylogenetic analysis in legumes using 39 gene families.	young polyploid events are easily diagnosed by various methods, but older polyploid events become increasingly difficult to identify as chromosomal rearrangements, tandem gene or partial chromosome duplications, changes in substitution rates among duplicated genes, pseudogenization or locus loss, and interlocus interactions complicate the means of inferring past genetic events. genomic data have provided valuable information about the polyploid history of numerous species, but on their own fail ...	2005	16012110
mustang is a novel family of domesticated transposase genes found in diverse angiosperms.	while transposons have traditionally been viewed as genomic parasites or "junk dna," the discovery of transposon-derived host genes has fueled an ongoing debate over the evolutionary role of transposons. in particular, while mobility-related open reading frames have been known to acquire host functions, the contribution of these types of events to the evolution of genes is not well understood. here we report that genome-wide searches for mutator transposase-derived host genes in arabidopsis thal ...	2005	15987878
genome organization of more than 300 defensin-like genes in arabidopsis.	defensins represent an ancient and diverse set of small, cysteine-rich, antimicrobial peptides in mammals, insects, and plants. according to published accounts, most species' genomes contain 15 to 50 defensins. starting with a set of largely nodule-specific defensin-like sequences (defls) from the model legume medicago truncatula, we built motif models to search the near-complete arabidopsis (arabidopsis thaliana) genome. we identified 317 defls, yet 80% were unannotated at the arabidopsis infor ...	2005	15955924
occurrence and characterization of pend proteins in angiosperms.	the pend protein is a dna-binding protein in the inner envelope membrane of the developing chloroplast. it consists of a short pre-sequence, an n-terminal dna-binding domain (cbzip), a central repeat domain, and a c-terminal transmembrane domain. pend homologs have been detected in various angiosperms, including arabidopsis thaliana, brassica napus, medicago truncatula, cucumber and cherry. monocot homologs have also been detected in barley and rice, but sequence conservation was low in monocots ...	2005	15834640
floral patterning in lotus japonicus.	floral patterning in papilionoideae plants, such as pea (pisum sativum) and medicago truncatula, is unique in terms of floral organ number, arrangement, and initiation timing as compared to other well-studied eudicots. to investigate the molecular mechanisms involved in the floral patterning in legumes, we have analyzed two mutants, proliferating floral meristem and proliferating floral organ-2 (pfo-2), obtained by ethyl methanesulfonate mutagenesis of lotus japonicus. these two mutants showed s ...	2005	15824286
conservation of arabidopsis flowering genes in model legumes.	the model plants arabidopsis (arabidopsis thaliana) and rice (oryza sativa) have provided a wealth of information about genes and genetic pathways controlling the flowering process, but little is known about the corresponding pathways in legumes. the garden pea (pisum sativum) has been used for several decades as a model system for physiological genetics of flowering, but the lack of molecular information about pea flowering genes has prevented direct comparison with other systems. to address th ...	2005	15778459
system, trends and perspectives of proteomics in dicot plants part ii: proteomes of the complex developmental stages.	this review is devoted to the proteomes of the complex developmental stages of dicotyledoneous (dicot) plant materials. the two core technologies, two-dimensional gel electrophoresis (2-dge) and mass spectrometry (ms), independently or in combination with each other, are propelling dicot plant proteomics to new discoveries and functions, with the establishment of tissue-specific and organelle proteomes, mostly in arabidopsis thaliana and medicago truncatula, revealing their complexity and specif ...	2005	15652803
system, trends and perspectives of proteomics in dicot plants part i: technologies in proteome establishment.	the first 3 years of the 21st century have seen the impact of plant proteomics on functional genomics that has enhanced our understanding, not only on the plant genome(s), but also more importantly, on the functional aspect of proteins. this is mainly due to availability of the complete genome sequence of the arabidopsis thaliana-a dicotyledoneous (dicot) model plant-and technological advancements in proteomics. proteomic analyses of a variety of dicot plants, including both arabidopsis and the ...	2005	15652802
the legume information system (lis): an integrated information resource for comparative legume biology.	the legume information system (lis) (http://www.comparative-legumes.org), developed by the national center for genome resources in cooperation with the usda agricultural research service (ars), is a comparative legume resource that integrates genetic and molecular data from multiple legume species enabling cross-species genomic and transcript comparisons. the lis virtual plant interface allows simplified and intuitive navigation of transcript data from medicago truncatula, lotus japonicus, glyci ...	2005	15608283
the medicago truncatula sunn gene encodes a clv1-like leucine-rich repeat receptor kinase that regulates nodule number and root length.	four medicago truncatula sunn mutants displayed shortened roots and hypernodulation under all conditions examined. the mutants, recovered in three independent genetic screens, all contained lesions in a leucine-rich repeat (lrr) receptor kinase. although the molecular defects among alleles varied, root length and the extent of nodulation were not significantly different between the mutants. sunn is expressed in shoots, flowers and roots. although previously reported grafting experiments showed t ...	2005	16240175
mining est databases to resolve evolutionary events in major crop species.	using plant est collections, we obtained 1392 potential gene duplicates across 8 plant species: zea mays, oryza sativa, sorghum bicolor, hordeum vulgare, solanum tuberosum, lycopersicon esculentum, medicago truncatula, and glycine max. we estimated the synonymous and nonsynonymous distances between each gene pair and identified two to three mixtures of normal distributions corresponding to one to three rounds of genome duplication in each species. within the poaceae, we found a conserved duplica ...	2004	15499401
estimating genome conservation between crop and model legume species.	legumes are simultaneously one of the largest families of crop plants and a cornerstone in the biological nitrogen cycle. we combined molecular and phylogenetic analyses to evaluate genome conservation both within and between the two major clades of crop legumes. genetic mapping of orthologous genes identifies broad conservation of genome macrostructure, especially within the galegoid legumes, while also highlighting inferred chromosomal rearrangements that may underlie the variation in chromoso ...	2004	15489274
widespread paleopolyploidy in model plant species inferred from age distributions of duplicate genes.	it is often anticipated that many of today's diploid plant species are in fact paleopolyploids. given that an ancient large-scale duplication will result in an excess of relatively old duplicated genes with similar ages, we analyzed the timing of duplication of pairs of paralogous genes in 14 model plant species. using est contigs (unigenes), we identified pairs of paralogous genes in each species and used the level of synonymous nucleotide substitution to estimate the relative ages of gene dupl ...	2004	15208399
comparative physical mapping reveals features of microsynteny between glycine max, medicago truncatula, and arabidopsis thaliana.	to gain insight into genomic relationships between soybean (glycine max) and medicago truncatula, eight groups of bacterial artificial chromosome (bac) contigs, together spanning 2.60 million base pairs (mb) in g. max and 1.56 mb in m. truncatula, were compared through high-resolution physical mapping combined with sequence and hybridization analysis of low-copy bac ends. cross-hybridization among g. max and m. truncatula contigs uncovered microsynteny in six of the contig groups and extensive m ...	2004	15060611
anthocyanidin reductases from medicago truncatula and arabidopsis thaliana.	anthocyanidin reductase (anr), encoded by the banyuls gene, is a newly discovered enzyme of the flavonoid pathway involved in the biosynthesis of condensed tannins. anr functions immediately downstream of anthocyanidin synthase to convert anthocyanidins into the corresponding 2,3-cis-flavan-3-ols. we report the biochemical properties of anrs from the model legume medicago truncatula (mtanr) and the model crucifer arabidopsis thaliana (atanr). both enzymes have high temperature optima. mtanr uses ...	2004	14725861
characterization of soybean genomic features by analysis of its expressed sequence tags.	we analyzed 314,254 soybean expressed sequence tags (ests), including 29,540 from our laboratory and 284,714 from genbank. these ests were assembled into 56,147 unigenes. about 76.92% of the unigenes were homologous to genes from arabidopsis thaliana ( arabidopsis). the putative products of these unigenes were annotated according to their homology with the categorized proteins of arabidopsis. genes corresponding to cell growth and/or maintenance, enzymes and cell communication belonged to the sl ...	2004	14624337
two classes of the cdh1-type activators of the anaphase-promoting complex in plants: novel functional domains and distinct regulation.	the cdc20 and cdh1/fzr proteins are the substrate-specific activators of the anaphase-promoting complex (apc). in medicago truncatula, the mtccs52a and mtccs52b proteins represent two subgroups of the cdh1-type activators, which display differences in their cell cycle regulation, structure, and function. the ccs52a transcripts are present in all phases of the cell cycle. by contrast, expression of ccs52b is restricted to late g2-phase and m-phase, and its induced overexpression in by2 cells inhi ...	2004	14742878
the symbiotic defect in a sinorhizobium meliloti lipopolysaccharide mutant can be overcome by expression of other surface polysaccharides.	in this work we have examined the extent of functional complementation in symbiosis among different sinorhizobium meliloti surface polysaccharides including lipopolysaccharide (lps). we show that a symbiotic deficiency associated with an lps defect can be reversed by appropriate expression of other surface polysaccharides such as galactoglucan (epsii) and a particular form of capsular polysaccharide (kdops). it is noteworthy that, while succinoglycan epsi and lps cannot functionally substitute f ...	2004	15567281
effect of salinity on root-nodule conductance to the oxygen diffusion in the medicago truncatula-sinorhizobium meliloti symbiosis.	in order to determine the effect of salinity on the nodule conductance, oxygen uptake by the nodulated roots was measured by registering the concentration of o(2) as a function of time in a tight incubator of known volume containing the nodulated roots of medicago truncatula. four lines, namely tn8.20 and tn6.18, originated from local populations, f83005.5 originated from var (france) and jemalong 6, a cultivar from australia, were hydroponically grown in 250 ml glass bottles under semi-controll ...	2004	15596103
metabolic profiling of medicago truncatula cell cultures reveals the effects of biotic and abiotic elicitors on metabolism.	gc-ms-based metabolite profiling was used to analyse the response of medicago truncatula cell cultures to elicitation with methyl jasmonate (meja), yeast elicitor (ye), or ultraviolet light (uv). marked changes in the levels of primary metabolites, including several amino acids, organic acids, and carbohydrates, were observed following elicitation with meja. a similar, but attenuated response was observed following ye elicitation, whereas little response was observed following uv elicitation. me ...	2004	15596476
fungal elicitation of signal transduction-related plant genes precedes mycorrhiza establishment and requires the dmi3 gene in medicago truncatula.	suppressive subtractive hybridization and expressed sequence tag sequencing identified 29 plant genes which are upregulated during the appressorium stage of mycorrhiza establishment between medicago truncatula j5 (myc+) and glomus mosseae. eleven genes coding plant proteins with predicted functions in signal transduction, transcription, and translation were investigated in more detail for their relation to early events of symbiotic interactions. expression profiling showed that the genes are act ...	2004	15597744
proteomic approach: identification of medicago truncatula proteins induced in roots after infection with the pathogenic oomycete aphanomyces euteiches.	the legume root rot disease caused by the oomycete pathogen aphanomyces euteiches is one major yield reducing factor in legume crop production. a comparative proteomic approach was carried out in order to identify proteins of the model legume medicago truncatula which are regulated after an infection with a. euteiches . several proteins were identified by two dimensional gel electrophoresis to be differentially expressed after pathogen challenge. densitometric evaluation of expression values sho ...	2004	15604668
methyl jasmonate and yeast elicitor induce differential transcriptional and metabolic re-programming in cell suspension cultures of the model legume medicago truncatula.	exposure of cell suspension cultures of medicago truncatula gaerth. to methyl jasmonate (meja) resulted in up to 50-fold induction of transcripts encoding the key triterpene biosynthetic enzyme beta-amyrin synthase (betaas; ec 5.4.99.-). transcripts reached maximum levels at 24 h post-elicitation with 0.5 mm meja. the entry point enzymes into the phenylpropanoid and flavonoid pathways, l: -phenylalanine ammonia-lyase (pal; ec 4.3.1.5) and chalcone synthase (chs; ec 2.3.1.74), respectively, were ...	2004	15605242
identification and characterization of several new members of the zip family of metal ion transporters in medicago truncatula.	to broaden our understanding of micronutrient metal transport in plants, we have identified cdnas for six new metal transporters in the model legume medicago truncatula. all of the predicted proteins have high similarity to the zip protein family, and have been designated mtzip1, mtzip3, mtzip4, mtzip5, mtzip6, and mtzip7. the six predicted proteins ranged from 350 to 372 amino acids in length; sequence analysis revealed that all proteins contained eight transmembrane domains and the highly cons ...	2004	15316291
microbial products trigger amino acid exudation from plant roots.	plants naturally cycle amino acids across root cell plasma membranes, and any net efflux is termed exudation. the dominant ecological view is that microorganisms and roots passively compete for amino acids in the soil solution, yet the innate capacity of roots to recover amino acids present in ecologically relevant concentrations is unknown. we find that, in the absence of culturable microorganisms, the influx rates of 16 amino acids (each supplied at 2.5 microm) exceed efflux rates by 5% to 545 ...	2004	15347793
nod factor-treated medicago truncatula roots and seeds show an increased number of nodules when inoculated with a limiting population of sinorhizobium meliloti.	medicago truncatula is a model legume plant that interacts symbiotically with sinorhizobium meliloti, the alfalfa symbiont. this process involves a molecular dialogue between the bacterium and the plant. legume roots exude flavonoids that induce the expression of a set of rhizobial genes, the nod genes, which are essential for nodulation and determination of the host range. in turn, nod genes control the synthesis of lipo-chito-oligosaccharides (lcos), nod factors, which are bacteria-to-plant si ...	2004	15361530
comprehensive metabolite profiling of sinorhizobium meliloti using gas chromatography-mass spectrometry.	a metabolite analysis of the soil bacterium sinorhizobium meliloti was established as a first step towards a better understanding of the symbiosis with its host plant medicago truncatula. a crucial step was the development of fast harvesting and extraction methods for the bacterial metabolites because of rapid changes in their composition. s. meliloti 1021 cell cultures grown in minimal medium were harvested by centrifugation, filtration or immediate freezing in liquid nitrogen followed by a lyo ...	2004	15372312
infection-related activation of the cg12 promoter is conserved between actinorhizal and legume-rhizobia root nodule symbiosis.	two nitrogen-fixing root nodule symbioses between soil bacteria and higher plants have been described: the symbiosis between legume and rhizobia and actinorhizal symbioses between plants belonging to eight angiosperm families and the actinomycete frankia. we have recently shown that the subtilisin-like ser protease gene cg12 (isolated from the actinorhizal plant casuarina glauca) is specifically expressed during plant cell infection by frankia. here we report on the study of c. glauca cg12 promo ...	2004	15466224
expression profiling in medicago truncatula identifies more than 750 genes differentially expressed during nodulation, including many potential regulators of the symbiotic program.	in this study, we describe a large-scale expression-profiling approach to identify genes differentially regulated during the symbiotic interaction between the model legume medicago truncatula and the nitrogen-fixing bacterium sinorhizobium meliloti. macro- and microarrays containing about 6,000 probes were generated on the basis of three cdna libraries dedicated to the study of root symbiotic interactions. the experiments performed on wild-type and symbiotic mutant material led us to identify a ...	2004	15466239
pharmacological evidence that multiple phospholipid signaling pathways link rhizobium nodulation factor perception in medicago truncatula root hairs to intracellular responses, including ca2+ spiking and specific enod gene expression.	rhizobium nodulation (nod) factors are specific lipochito-oligosaccharide signals essential for initiating in root hairs of the host legume developmental responses that are required for controlled entry of the microsymbiont. in this article, we focus on the nod factor signal transduction pathway leading to specific and cell autonomous gene activation in medicago truncatula cv jemalong in a study making use of the nod factor-inducible mtenod11 gene. first, we show that pharmacological antagonists ...	2004	15489277
nip, a symbiotic medicago truncatula mutant that forms root nodules with aberrant infection threads and plant defense-like response.	to investigate the legume-rhizobium symbiosis, we isolated and studied a novel symbiotic mutant of the model legume medicago truncatula, designated nip (numerous infections and polyphenolics). when grown on nitrogen-free media in the presence of the compatible bacterium sinorhizobium meliloti, the nip mutant showed nitrogen deficiency symptoms. the mutant failed to form pink nitrogen-fixing nodules that occur in the wild-type symbiosis, but instead developed small bump-like nodules on its roots ...	2004	15516506
lin, a medicago truncatula gene required for nodule differentiation and persistence of rhizobial infections.	ethyl methanesulfonate mutagenesis of the model legume medicago truncatula has previously identified several genes required for early steps in nodulation. here, we describe a new mutant that is defective in intermediate steps of nodule differentiation. the lin (lumpy infections) mutant is characterized by a 4-fold reduction in the number of infections, all of which arrest in the root epidermis, and by nodule primordia that initiate normally but fail to mature. genetic analyses indicate that the ...	2004	15516512
a dual-genome symbiosis chip for coordinate study of signal exchange and development in a prokaryote-host interaction.	the soil-dwelling alpha-proteobacterium sinorhizobium meliloti engages in a symbiosis with legumes: s. meliloti elicits the formation of plant root nodules where it converts dinitrogen to ammonia for use by the plant in exchange for plant photosynthate. to study the coordinate differentiation of s. meliloti and its legume partner during nodule development, we designed a custom affymetrix genechip with the complete s. meliloti genome and approximately 10,000 probe sets for the plant host, medicag ...	2004	15542588
molecular and cell biology of a family of voltage-dependent anion channel porins in lotus japonicus.	voltage-dependent anion channels (vdacs) are generally considered as the main pathway for metabolite transport across the mitochondrial outer membrane. recent proteomic studies on isolated symbiosome membranes from legume nodules indicated that vdacs might also be involved in transport of nutrients between plants and rhizobia. in an attempt to substantiate this, we carried out a detailed molecular and cellular characterization of vdacs in lotus japonicus and soybean (glycine max). database searc ...	2004	14657408
the promoter of the vicia faba l. leghemoglobin gene vflb29 is specifically activated in the infected cells of root nodules and in the arbuscule-containing cells of mycorrhizal roots from different legume and nonlegume plants.	the vflb29 leghemoglobin gene promoter was polymerase chain reaction-amplified from a vicia faba genomic library and was fused to the gusaint coding region. expression of the chimeric gene was analyzed in transgenic hairy roots of the legumes v. faba, v. hirsuta, and medicago truncatula as well as in transgenic nicotiana tabacum plants. the vflb29 promoter was found to be specifically active not only in the infected cells of the nitrogen-fixing zone of root nodules but also in arbuscule-containi ...	2004	14714869
an auxin-inducible gene from loblolly pine (pinus taeda l.) is differentially expressed in mature and juvenile-phase shoots and encodes a putative transmembrane protein.	we have isolated a gene from loblolly pine, 5ng4, that is highly and specifically induced by auxin in juvenile loblolly pine shoots prior to adventitious root formation, but substantially down-regulated in physiologically mature shoots that are adventitious rooting incompetent. 5ng4 was highly auxin-induced in roots, stems and hypocotyls, organs that can form either lateral or adventitious roots following an auxin treatment, but was not induced to the same level in needles and cotyledons, organs ...	2004	14722770
plant and bacterial symbiotic mutants define three transcriptionally distinct stages in the development of the medicago truncatula/sinorhizobium meliloti symbiosis.	in the medicago truncatula/sinorhizobium meliloti symbiosis, the plant undergoes a series of developmental changes simultaneously, creating a root nodule and allowing bacterial entry and differentiation. our studies of plant genes reveal novel transcriptional regulation during the establishment of the symbiosis and identify molecular markers that distinguish classes of plant and bacterial symbiotic mutants. we have identified three symbiotically regulated plant genes encoding a beta,1-3 endogluc ...	2004	14739349
biochemical characterization of symbiosome membrane proteins from medicago truncatula root nodules.	the symbiosome membrane represents a specialized plant membrane that forms both a structural and a functional interface between the legume plant and its bacterial counterpart. in this study, the symbiosome membrane protein profile from the model system medicago truncatula and the corresponding bacterium sinorhizobium meliloti was examined using two-dimensional electrophoresis and microcapillary high-performance liquid chromatography (hplc) tandem mass spectrometry. the identities of 51 proteins ...	2004	14760646
a putative ca2+ and calmodulin-dependent protein kinase required for bacterial and fungal symbioses.	legumes can enter into symbiotic relationships with both nitrogen-fixing bacteria (rhizobia) and mycorrhizal fungi. nodulation by rhizobia results from a signal transduction pathway induced in legume roots by rhizobial nod factors. dmi3, a medicago truncatula gene that acts immediately downstream of calcium spiking in this signaling pathway and is required for both nodulation and mycorrhizal infection, has high sequence similarity to genes encoding calcium and calmodulin-dependent protein kinase ...	2004	14963335
molecular and biochemical analysis of two cdna clones encoding dihydroflavonol-4-reductase from medicago truncatula.	dihydroflavonol-4-reductase (dfr; ec1.1.1.219) catalyzes a key step late in the biosynthesis of anthocyanins, condensed tannins (proanthocyanidins), and other flavonoids important to plant survival and human nutrition. two dfr cdna clones (mtdfr1 and mtdfr2) were isolated from the model legume medicago truncatula cv jemalong. both clones were functionally expressed in escherichia coli, confirming that both encode active dfr proteins that readily reduce taxifolin (dihydroquercetin) to leucocyanid ...	2004	14976232
the typa gene is required for stress adaptation as well as for symbiosis of sinorhizobium meliloti 1021 with certain medicago truncatula lines.	in this article, we describe the typa gene of sinorhizobium meliloti, the orthologue of typa/bipa genes found in a wide range of bacteria. we found that typa was required for survival of s. meliloti under certain stress conditions, such as growth at low temperature or low ph and in the presence of sodium dodecyl sulfate (sds). the cold-sensitive phenotype of both escherichia coli bipa and s. meliloti typa mutants were cross-complemented, indicating that the two genes are functionally equivalent. ...	2004	15000390
isolation and characterization of the early nodule-specific protein homologue (hev b 13), an allergenic lipolytic esterase from hevea brasiliensis latex.	recurring reports of a highly allergenic 42-46-kda protein in hevea brasiliensis latex appeared to have been resolved with the discovery of a 43-kda allergenic latex protein that was a homologue to patatin. however, the low to moderate prevalence of sensitization to the protein, designated hev b 7, among latex-allergic patients could not adequately explain the frequent observations of the 42-46-kda allergen. this led to the hypothesis that another, more allergenic protein of a similar molecular ...	2004	15024009
a nonsymbiotic root hair tip growth phenotype in nork-mutated legumes: implications for nodulation factor-induced signaling and formation of a multifaceted root hair pocket for bacteria.	the medicago truncatula does not make infections (dmi2) mutant is mutated in the nodulation receptor-like kinase, nork. here, we report that nork-mutated legumes of three species show an enhanced touch response to experimental handling, which results in a nonsymbiotic root hair phenotype. when care is taken not to induce this response, dmi2 root hairs respond morphologically like the wild type to nodulation factor (nf). global nf application results in root hair deformation, and nf spot applicat ...	2004	15031407
phytohormonal responses in enod40-overexpressing plants of medicago truncatula and rice.	phytohormones are well-known regulators of the symbiotic rhizobium-legume association in the plant host. the enod40 nodulin gene is associated with the earliest phases of the nodule organogenesis programme in the legume host and modifying its expression resulted in perturbations of nodule development in medicago truncatula. therefore in our pursuit to mimic the initial signal transduction steps of legume nodulation in the alien physiological set-up of a rice plant, we have expressed the mtenod40 ...	2004	15032885
enod40, a short open reading frame-containing mrna, induces cytoplasmic localization of a nuclear rna binding protein in medicago truncatula.	in eukaryotes, diverse mrnas containing only short open reading frames (sorf-mrnas) are induced at specific stages of development. their mechanisms of action may involve the rna itself and/or sorf-encoded oligopeptides. enod40 genes code for highly structured plant sorf-mrnas involved in root nodule organogenesis. a novel rna binding protein interacting with the enod40 rna, mtrbp1 (for medicago truncatula rna binding protein 1), was identified using a yeast three-hybrid screening. immunolocaliza ...	2004	15037734
rna interference in agrobacterium rhizogenes-transformed roots of arabidopsis and medicago truncatula.	rna interference (rnai) is a powerful reverse genetic tool to study gene function. the data presented here show that agrobacterium rhizogenes-mediated rnai is a fast and effective tool to study genes involved in root biology. the arabidopsis gene kojak, involved in root hair development, was efficiently knocked down. a. rhizogenes-mediated root transformation is a fast method to generate adventitious, genetically transformed roots. in order to select for co-transformed roots a binary vector was ...	2004	15073217
a natural variant of a host rna-dependent rna polymerase is associated with increased susceptibility to viruses by nicotiana benthamiana.	nicotiana benthamiana often displays more intense symptoms after infection by rna viruses than do other nicotiana species. here, we examined the role of rna-dependent rna polymerases (rdrps) in n. benthamiana antiviral defense. cdnas representing only two genes encoding rdrps were identified in n. benthamiana. one rdrp was similar in sequence to sde1/sgs2 required for maintenance of transgene silencing, whereas the second, named nbrdrp1m, was >90% identical in sequence to the salicylic acid (sa) ...	2004	15079073
sinorhizobium meliloti-induced chitinase gene expression in medicago truncatula ecotype r108-1: a comparison between symbiosis-specific class v and defence-related class iv chitinases.	the medicago truncatula (gaertn.) ecotypes jemalong a17 and r108-1 differ in sinorhizobium meliloti-induced chitinase gene expression. the pathogen-inducible class iv chitinase gene, mtchit 4, was strongly induced during nodule formation of the ecotype jemalong a17 with the s. meliloti wild-type strain 1021. in the ecotype r108-1, the s. meliloti wild types sm1021 and sm41 did not induce mtchit 4 expression. on the other hand, expression of the putative class v chitinase gene, mtchit 5, was foun ...	2004	15107993
construction and validation of cdna-based mt6k-rit macro- and microarrays to explore root endosymbioses in the model legume medicago truncatula.	to construct macro- and microarray tools suitable for expression profiling in root endosymbioses of the model legume medicago truncatula, we pcr-amplified a total of 6048 cdna probes representing genes expressed in uninfected roots, mycorrhizal roots and young root nodules [nucleic acids res. 30 (2002) 5579]. including additional probes for either tissue-specific or constitutively expressed control genes, 5651 successfully amplified gene-specific probes were used to grid macro- and to spot micro ...	2004	15129719
six nonnodulating plant mutants defective for nod factor-induced transcriptional changes associated with the legume-rhizobia symbiosis.	as the legume-rhizobia symbiosis is established, the plant recognizes bacterial-signaling molecules, nod factors (nfs), and initiates transcriptional and developmental changes within the root to allow bacterial invasion and the construction of a novel organ, the nodule. plant mutants defective in nodule initiation (nod(-)) are thought to have defects in nf-signal transduction. however, it is unknown whether wt plants respond to nf-independent bacterial-derived signals or whether nod(-) plant mut ...	2004	15220482
sinorhizobium meliloti metabolism in the root nodule: a proteomic perspective.	the proteome of the model symbiotic bacterium, sinorhizobium meliloti was examined to determine the enzymatic reactions and cell processes that occur when s. meliloti occupies the root nodules of medicago truncatula and melilotus alba. the proteomes of the nodule bacteria were compared to that of s. meliloti grown under laboratory cultured conditions as an additional control. all the detectable protein spots on the two-dimensional (2-d) gels between ph 4-7 were analyzed. in total, the identity o ...	2004	15221743
impact of sewage sludges on medicago truncatula symbiotic proteome.	the effects of sewage sludges were investigated on the symbiotic interactions between the model plant medicago truncatula and the arbuscular mycorrhizal fungus glomus mosseae or the rhizobial bacteria sinorhizobium meliloti. by comparison to a control sludge showing positive effects on plant growth and root symbioses, sludges enriched with polycylic aromatic hydrocarbons or heavy metals were deleterious. symbiosis-related proteins were detected and identified by two-dimensional electrophoresis a ...	2004	15276460
resistance of glycine species and various cultivated legumes to the soybean aphid (homoptera: aphididae).	the soybean aphid, aphis glycines matsumura, is a new pest of soybean, glycine max (l.) merr., in north america. it has become widespread on soybean in north america since it was first identified in the midwest in 2000. species of rhamnus l. (buckthorn) are the primary hosts of a. glycines, and soybean is known as a secondary host. there is limited information about the secondary host range of a. glycines. aphid colonization on various legume hosts was compared in choice experiments. aphid colon ...	2004	15279293
differential antifungal and calcium channel-blocking activity among structurally related plant defensins.	plant defensins are a family of small cys-rich antifungal proteins that play important roles in plant defense against invading fungi. structures of several plant defensins share a cys-stabilized alpha/beta-motif. structural determinants in plant defensins that govern their antifungal activity and the mechanisms by which they inhibit fungal growth remain unclear. alfalfa (medicago sativa) seed defensin, msdef1, strongly inhibits the growth of fusarium graminearum in vitro, and its antifungal acti ...	2004	15299136
cytological, genetic, and molecular analysis to characterize compatible and incompatible interactions between medicago truncatula and colletotrichum trifolii.	in this study, a new pathosystem was established using the model plant medicago truncatula and colletotrichum trifolii, the causal agent of anthracnose on medicago sativa. screening of a few m. truncatula lines identified jemalong and f83005.5 as resistant and susceptible to colletotrichum trifolii race 1, respectively. symptom analysis and cytological studies indicated that resistance of jemalong was associated with a hypersensitive response of the plant. the two selected lines were crossed, an ...	2004	15305612
use of the fluorescent timer dsred-e5 as reporter to monitor dynamics of gene activity in plants.	fluorescent proteins, such as green fluorescent protein and red fluorescent protein (dsred), have become frequently used reporters in plant biology. however, their potential to monitor dynamic gene regulation is limited by their high stability. the recently made dsred-e5 variant overcame this problem. dsred-e5 changes its emission spectrum over time from green to red in a concentration independent manner. therefore, the green to red fluorescence ratio indicates the age of the protein and can be ...	2004	15326279
computational identification and characterization of novel genes from legumes.	the fabaceae, the third largest family of plants and the source of many crops, has been the target of many genomic studies. currently, only the grasses surpass the legumes for the number of publicly available expressed sequence tags (ests). the quantity of sequences from diverse plants enables the use of computational approaches to identify novel genes in specific taxa. we used blast algorithms to compare unigene sets from medicago truncatula, lotus japonicus, and soybean (glycine max and glycin ...	2004	15266052
a ca2+/calmodulin-dependent protein kinase required for symbiotic nodule development: gene identification by transcript-based cloning.	in the establishment of the legume-rhizobial symbiosis, bacterial lipochitooligosaccharide signaling molecules termed nod factors activate the formation of a novel root organ, the nodule. nod factors elicit several responses in plant root hair cells, including oscillations in cytoplasmic calcium levels (termed calcium spiking) and alterations in root hair growth. a number of plant mutants with defects in the nod factor signaling pathway have been identified. one such medicago truncatula mutant, ...	2004	15070781
nodule initiation involves the creation of a new symplasmic field in specific root cells of medicago species.	the organogenesis of nitrogen-fixing nodules in legume plants is initiated in specific root cortical cells and regulated by long-distance signaling and carbon allocation. here, we explore cell-to-cell communication processes that occur during nodule initiation in medicago species and their functional relevance using a combination of fluorescent tracers, electron microscopy, and transgenic plants. nodule initiation induced symplasmic continuity between the phloem and nodule initials. macromolecul ...	2003	14615602
nod factor inhibition of reactive oxygen efflux in a host legume.	hydrogen peroxide (h(2)o(2)) efflux was measured from medicago truncatula root segments exposed to purified nod factor and to poly-galua (pga) heptamers. nod factor, at concentrations > 100 pm, reduced h(2)o(2) efflux rates to 60% of baseline levels beginning 20 to 30 min after exposure, whereas the pga elicitor, at > 75 nm, caused a rapid increase in h(2)o(2) efflux to >200% of baseline rates. pretreatment of plants with nod factor alters the effect of pga by limiting the maximum h(2)o(2) efflu ...	2003	12913174
mapping the proteome of barrel medic (medicago truncatula).	a survey of six organ-/tissue-specific proteomes of the model legume barrel medic (medicago truncatula) was performed. two-dimensional polyacrylamide gel electrophoresis reference maps of protein extracts from leaves, stems, roots, flowers, seed pods, and cell suspension cultures were obtained. five hundred fifty-one proteins were excised and 304 proteins identified using peptide mass fingerprinting and matrix-assisted laser desorption ionization time-of-flight mass spectrometry. nanoscale high- ...	2003	12644662
dual genetic pathways controlling nodule number in medicago truncatula.	we report the isolation and characterization of a new medicago truncatula hyper-nodulation mutant, designated sunn (super numeric nodules). similar to the previously described ethylene-insensitive mutant sickle, sunn exhibits a 10-fold increase in the number of nodules within the primary nodulation zone. despite this general similarity, these two mutants are readily distinguished based on anatomical, genetic, physiological, and molecular criteria. in contrast to sickle, where insensitivity to et ...	2003	12644652
nodule-specific modulation of glutamine synthetase in transgenic medicago truncatula leads to inverse alterations in asparagine synthetase expression.	transgenic medicago truncatula plants were produced harboring chimeric gene constructs of the glutamine synthetase (gs) cdna clones (mtgs1a or mtgs1b) fused in sense or antisense orientation to the nodule-specific leghemoglobin promoter mtlb1. a series of transgenic plants were obtained showing a 2- to 4-fold alteration in nodule gs activity when compared with control plants. western and northern analyses revealed that the increased or decreased levels of gs activity correlate with the amount of ...	2003	12970490
extensive and specific responses of a eukaryote to bacterial quorum-sensing signals.	many bacteria use n-acyl homoserine lactone (ahl) signals to coordinate the behavior of individual cells in a local population. the successful infection of eukaryotic hosts by bacteria seems to depend particularly on such ahl-mediated "quorum-sensing" regulation. we have used proteome analysis to show that a eukaryotic host, the model legume medicago truncatula, is able to detect nanomolar to micromolar concentrations of bacterial ahls from both symbiotic (sinorhizobium meliloti) and pathogenic ...	2003	12511600
role of anthocyanidin reductase, encoded by banyuls in plant flavonoid biosynthesis.	condensed tannins (cts) are flavonoid oligomers, many of which have beneficial effects on animal and human health. the flavanol (-)-epicatechin is a component of many cts and contributes to flavor and astringency in tea and wine. we show that the banyuls (ban) genes from arabidopsis thaliana and medicago truncatula encode anthocyanidin reductase, which converts anthocyanidins to their corresponding 2,3-cis-flavan-3-ols. ectopic expression of ban in tobacco flower petals and arabidopsis leaves re ...	2003	12532018
sinorhizobium meliloti acpxl mutant lacks the c28 hydroxylated fatty acid moiety of lipid a and does not express a slow migrating form of lipopolysaccharide.	lipid a is the hydrophobic anchor of lipopolysaccharide (lps) in the outer membrane of gram-negative bacteria. lipid a of all rhizobiaceae is acylated with a long fatty acid chain, 27-hydroxyoctacosanoic acid. biosynthesis of this long acyl substitution requires a special acyl carrier protein, acpxl, which serves as a donor of c28 (omega-1)-hydroxylated fatty acid for acylation of rhizobial lipid a (brozek, k.a., carlson, r.w., and raetz, c. r. (1996) j. biol. chem. 271, 32126-32136). to determi ...	2003	12566460
kinetics and strain specificity of rhizosphere and endophytic colonization by enteric bacteria on seedlings of medicago sativa and medicago truncatula.	the presence of human-pathogenic, enteric bacteria on the surface and in the interior of raw produce is a significant health concern. several aspects of the biology of the interaction between these bacteria and alfalfa (medicago sativa) seedlings are addressed here. a collection of enteric bacteria associated with alfalfa sprout contaminations, along with escherichia coli k-12, salmonella enterica serotype typhimurium strain atcc 14028, and an endophyte of maize, klebsiella pneumoniae 342, were ...	2003	12620870