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large-scale transcriptome analysis in chickpea (cicer arietinum l.), an orphan legume crop of the semi-arid tropics of asia and africa.chickpea (cicer arietinum l.) is an important legume crop in the semi-arid regions of asia and africa. gains in crop productivity have been low however, particularly because of biotic and abiotic stresses. to help enhance crop productivity using molecular breeding techniques, next generation sequencing technologies such as roche/454 and illumina/solexa were used to determine the sequence of most gene transcripts and to identify drought-responsive genes and gene-based molecular markers. a total o ...201121615673
development and use of genic molecular markers (gmms) for construction of a transcript map of chickpea (cicer arietinum l.).a transcript map has been constructed by the development and integration of genic molecular markers (gmms) including single nucleotide polymorphism (snp), genic microsatellite or simple sequence repeat (ssr) and intron spanning region (isr)-based markers, on an inter-specific mapping population of chickpea, the third food legume crop of the world and the first food legume crop of india. for snp discovery through allele re-sequencing, primer pairs were designed for 688 genes/expressed sequence ta ...201121384113
arbuscular mycorrhizal hyphopodia and germinated spore exudates trigger ca2+ spiking in the legume and nonlegume root epidermis.• the aim of this study was to investigate ca(2+) responses to endosymbiotic arbuscular mycorrhizal (am) fungi in the host root epidermis following pre-infection hyphopodium formation in both legumes and nonlegumes, and to determine to what extent these responses could be mimicked by germinated fungal spore exudate. • root organ cultures of both medicago truncatula and daucus carota, expressing the nuclear-localized cameleon reporter nupyc2.1, were used to monitor am-elicited ca(2+) responses in ...201120880223
fenpropimorph and fenhexamid impact phosphorus translocation by arbuscular mycorrhizal fungi.fenpropimorph and fenhexamid are sterol biosynthesis inhibitor (sbi) molecules widely used to control diseases in agriculture. both molecules, at increasing concentrations, have been shown to impact on the non-target arbuscular mycorrhizal (am) fungi. root colonization, spore production and mycelium architecture, including the branched absorbing structures which are thought to be involved in phosphorus (p) uptake, were affected. in the present study, we investigated the capacity of glomus sp. mu ...201121085999
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
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
developing a method for customized induction of flowering.the ability to induce flowering on demand is of significant biotechnological interest. ft protein has been recently identified as an important component of the mobile flowering hormone, florigen, whose function is conserved across the plant kingdom. we therefore focused on manipulation of both endogenous and heterologous ft genes to develop a floral induction system where flowering would be inhibited until it was induced on demand. the concept was tested in the model plant arabidopsis thaliana ( ...201121481273
assembling a puzzle of dispersed retrotransposable sequences in the genome of chickpea (cicer arietinum l.).several repetitive elements are known to be present in the genome of chickpea (cicer arietinum l.) including satellite dna and en/spm transposons as well as two dispersed, highly repetitive elements, carep1 and carep2. pcr was used to prove that carep1, carep2, and previously isolated carep3 of c. arietinum represent different segments of a highly repetitive ty3-gypsy-like retrotransposon (metaviridae) designated carep that makes up large parts of the intercalary heterochromatin. the full sequen ...201021164541
integration of novel ssr and gene-based snp marker loci in the chickpea genetic map and establishment of new anchor points with medicago truncatula genome.this study presents the development and mapping of simple sequence repeat (ssr) and single nucleotide polymorphism (snp) markers in chickpea. the mapping population is based on an inter-specific cross between domesticated and non-domesticated genotypes of chickpea (cicer arietinum icc 4958 x c. reticulatum pi 489777). this same population has been the focus of previous studies, permitting integration of new and legacy genetic markers into a single genetic map. we report a set of 311 novel ssr ma ...201020098978
polyploidy did not predate the evolution of nodulation in all legumes.several lines of evidence indicate that polyploidy occurred by around 54 million years ago, early in the history of legume evolution, but it has not been known whether this event was confined to the papilionoid subfamily (papilionoideae; e.g. beans, medics, lupins) or occurred earlier. determining the timing of the polyploidy event is important for understanding whether polyploidy might have contributed to rapid diversification and radiation of the legumes near the origin of the family; and whet ...201020661290
a platform for functional prediction and comparative analyses of transcription factors of legumes and beyond.sequence-specific dna-binding transcription factors (tfs) are key molecular switches that control many of the biological processes in a cell or organism. recent completion of the genomic sequences of soybean (glycine max), locus japonicus and medicago truncatula has enabled us to carry out large-scale data mining to identify and annotate regulatory tfs for functional and comparative genomics of the tf repertoires of these three major legumes in themselves or with those of other species. the iden ...201020215877
a comparison of global, gene-specific, and relaxed clock methods in a comparative genomics framework: dating the polyploid history of soybean (glycine max).it is widely recognized that many genes and lineages do not adhere to a molecular clock, yet molecular clocks are commonly used to date divergences in comparative genomic studies. we test the application of a molecular clock across genes and lineages in a phylogenetic framework utilizing 12 genes linked in a 1-mb region on chromosome 13 of soybean (glycine max); homoeologous copies of these genes formed by polyploidy in glycine; and orthologous copies in g. tomentella, phaseolus vulgaris, and me ...201020705909
legumetfdb: an integrative database of glycine max, lotus japonicus and medicago truncatula transcription factors.we have established a database named legumetfdb to provide access to transcription factor (tf) repertoires of three major legume species: soybean (glycine max), lotus japonicus and medicago truncatula. legumetfdb integrates unique information for each tf gene and family, including sequence features, gene promoters, domain alignments, gene ontology (go) assignment and sequence comparison data derived from comparative analysis with tfs found within legumes, in arabidopsis, rice and poplar as well ...201019933159
inactivation of duplicated nod factor receptor 5 (nfr5) genes in recessive loss-of-function non-nodulation mutants of allotetraploid soybean (glycine max l. merr.).chemically induced non-nodulating nod139 and nn5 mutants of soybean (glycine max) show no visible symptoms in response to rhizobial inoculation. both exhibit recessive mendelian inheritance suggesting loss of function. by allele determination and genetic complementation in nod139 and nn5, two highly related lipo-oligochitin lysm-type receptor kinase genes in glycine max were cloned; they are presumed to be the critical nodulation-inducing (nod) factor receptor similar to those of lotus japonicus ...201020007291
an nac transcription factor orchestrates multiple features of cell wall development in medicago truncatula.to identify genes controlling secondary cell wall biosynthesis in the model legume medicago truncatula, we screened a tnt1 retrotransposon insertion mutant population for plants with altered patterns of lignin autofluorescence. from more than 9000 r1 plants screened, four independent lines were identified with a total lack of lignin in the interfascicular region. the mutants also showed loss of lignin in phloem fibers, reduced lignin in vascular elements, failure in anther dehiscence and absence ...201020408998
flavonoids: new roles for old molecules.flavonoids are ubiquitous in the plant kingdom and have many diverse functions including defense, uv protection, auxin transport inhibition, allelopathy, and flower coloring. interestingly, these compounds also have considerable biological activity in plant, animal and bacterial systems - such broad activity is accomplished by few compounds. yet, for all the research over the last three decades, many of the cellular targets of these secondary metabolites are unknown. the many mutants available i ...201020074144
genome-wide investigation reveals high evolutionary rates in annual model plants.rates of molecular evolution vary widely among species. while significant deviations from molecular clock have been found in many taxa, effects of life histories on molecular evolution are not fully understood. in plants, annual/perennial life history traits have long been suspected to influence the evolutionary rates at the molecular level. to date, however, the number of genes investigated on this subject is limited and the conclusions are mixed. to evaluate the possible heterogeneity in evolu ...201021062446
molecular and phylogenetic characterization of the sieve element occlusion gene family in fabaceae and non-fabaceae plants.the phloem of dicotyledonous plants contains specialized p-proteins (phloem proteins) that accumulate during sieve element differentiation and remain parietally associated with the cisternae of the endoplasmic reticulum in mature sieve elements. wounding causes p-protein filaments to accumulate at the sieve plates and block the translocation of photosynthate. specialized, spindle-shaped p-proteins known as forisomes that undergo reversible calcium-dependent conformational changes have evolved ex ...201020932300
conservation in function of a scar/wave component during infection thread and root hair growth in medicago truncatula.nitrogen-fixing symbioses of plants are often associated with bacterially infected nodules where nitrogen fixation occurs. the plant host facilitates bacterial infection with the formation of infection threads, unique structures associated with these symbioses, which are invaginations of the host cell with the capability of traversing cellular junctions. here, we show that the infection thread shares mechanistic similarities to polar-growing cells, because the required for infection thread (rit) ...201020731530
syntenic relationships among legumes revealed using a gene-based genetic linkage map of common bean (phaseolus vulgaris l.).molecular linkage maps are an important tool for gene discovery and cloning, crop improvement, further genetic studies, studies on diversity and evolutionary history, and cross-species comparisons. linkage maps differ in both the type of marker and type of population used. in this study, gene-based markers were used for mapping in a recombinant inbred (ri) population of phaseolus vulgaris l. p. vulgaris, common dry bean, is an important food source, economic product, and model organism for the l ...201020607211
walls are thin 1 (wat1), an arabidopsis homolog of medicago truncatula nodulin21, is a tonoplast-localized protein required for secondary wall formation in fibers.by combining zinnia elegans in vitro tracheary element genomics with reverse genetics in arabidopsis, we have identified a new upstream component of secondary wall formation in xylary and interfascicular fibers. walls are thin 1 (wat1), an arabidopsis thaliana homolog of medicago truncatula nodulin 21 (mtn21), encodes a plant-specific, predicted integral membrane protein, and is a member of the plant drug/metabolite exporter (p-dme) family (transporter classification number: tc 2.a.7.3). althoug ...201020497379
comparison of homoeolocus organisation in paired bac clones from white clover (trifolium repens l.) and microcolinearity with model legume species.white clover (trifolium repens l.) is an outbreeding allotetraploid species and an important forage legume in temperate grassland agriculture. comparison of sub-genome architecture and study of nucleotide sequence diversity within allopolyploids provides insight into evolutionary divergence mechanisms, and is also necessary for the development of whole-genome sequencing strategies. this study aimed to evaluate the degree of divergence between the o and p' sub-genomes of white clover through sequ ...201020492736
an integrated transcriptome atlas of the crop model glycine max, and its use in comparative analyses in plants.soybean (glycine max l.) is a major crop providing an important source of protein and oil, which can also be converted into biodiesel. a major milestone in soybean research was the recent sequencing of its genome. the sequence predicts 69,145 putative soybean genes, with 46,430 predicted with high confidence. in order to examine the expression of these genes, we utilized the illumina solexa platform to sequence cdna derived from 14 conditions (tissues). the result is a searchable soybean gene ex ...201020408999
mutation of wrky transcription factors initiates pith secondary wall formation and increases stem biomass in dicotyledonous plants.stems of dicotyledonous plants consist of an outer epidermis, a cortex, a ring of secondarily thickened vascular bundles and interfascicular cells, and inner pith parenchyma cells with thin primary walls. it is unclear how the different cell layers attain and retain their identities. here, we show that wrky transcription factors are in part responsible for the parenchymatous nature of the pith cells in dicotyledonous plants. we isolated mutants of medicago truncatula and arabidopsis thaliana wit ...201021135241
identification of potential early regulators of aphid resistance in medicago truncatula via transcription factor expression profiling.*resistance to aphids has been identified in a number of plant species, yet the molecular mechanisms underlying aphid resistance remain largely unknown. *using high-throughput quantitative real-time pcr technology, the transcription profiles of 752 putative medicago truncatula transcription factor genes were analysed in a pair of susceptible and resistant closely related lines of m. truncatula following 6 and 12 h of bluegreen aphid (acyrthosiphon kondoi) infestation. *eighty-two transcription f ...201020345634
transcript profiling of two alfalfa genotypes with contrasting cell wall composition in stems using a cross-species platform: optimizing analysis by masking biased probes.the genechip(r) medicago genome array, developed for medicago truncatula, is a suitable platform for transcript profiling in tetraploid alfalfa [medicago sativa (l.) subsp. sativa]. however, previous research involving cross-species hybridization (csh) has shown that sequence variation between two species can bias transcript profiling by decreasing sensitivity (number of expressed genes detected) and the accuracy of measuring fold-differences in gene expression.201020497574
mediplex - a tool to combine in silico & experimental gene expression profiles of the model legume medicago truncatula.expressed sequence tags (ests) are in general used to gain a first insight into gene activities from a species of interest. subsequently, and typically based on a combination of est and genome sequences, microarray-based expression analyses are performed for a variety of conditions. in some cases, a multitude of est and microarray experiments are conducted for one species, covering different tissues, cell states, and cell types. under these circumstances, the challenge arises to combine results ...201020958970
medicago truncatula contains a second gene encoding a plastid located glutamine synthetase exclusively expressed in developing seeds.nitrogen is a crucial nutrient that is both essential and rate limiting for plant growth and seed production. glutamine synthetase (gs), occupies a central position in nitrogen assimilation and recycling, justifying the extensive number of studies that have been dedicated to this enzyme from several plant sources. all plants species studied to date have been reported as containing a single, nuclear gene encoding a plastid located gs isoenzyme per haploid genome. this study reports the existence ...201020723225
[tobacco transformants expressing the medicago truncatula ornithine aminotransferase cdna].the medicago truncatula ornithine aminotransferase cdna was cloned under the potent constitutive 35s rna promoter of the cauliflower mosaic virus and transferred into the genome of tobacco nicotiana tabacum sr1 plants. transformed tobacco plants grew better in salinity stress, but did not differ in proline content under normal or stress conditions from control plants. it was assumed that the role of ornithine aminotransferase in the molecular mechanisms of stress resistance is not associated wit ...201020795505
differential gel electrophoresis (dige) to quantitatively monitor early symbiosis- and pathogenesis-induced changes of the medicago truncatula root proteome.symbiosis- and pathogenesis-related early protein induction patterns in the model legume medicago truncatula were analysed with two-dimensional differential gel electrophoresis. two symbiotic soil microorganisms (glomus intraradices, sinorhizobium meliloti) were used in single infections and in combination with a secondary pathogenic infection by the oomycete aphanomyces euteiches. proteomic analyses performed 6 and 24h after inoculations led to identification of 87 differentially induced protei ...201019895911
a comparison of two class 10 pathogenesis-related genes from alfalfa and their activation by multiple stresses and stress-related signaling molecules.a collection of 29 pathogenesis-related 10 (pr10) genes of medicago sativa and medicago truncatula showed that they were almost all obtained from cdna libraries of tissues undergoing abiotic or biotic stresses. the predicted proteins could be divided into two subclasses, pr10.1 and pr10.2, but in silico predicted models of their three-dimensional structures revealed that they could be further divided based on size of the hydrophobic internal cavity and number of β-bulges. a comparison of the exp ...201020703880
the b-3 ethylene response factor mterf1-1 mediates resistance to a subset of root pathogens in medicago truncatula without adversely affecting symbiosis with rhizobia.the fungal necrotrophic pathogen rhizoctonia solani is a significant constraint to a range of crops as diverse as cereals, canola, and legumes. despite wide-ranging germplasm screens in many of these crops, no strong genetic resistance has been identified, suggesting that alternative strategies to improve resistance are required. in this study, we characterize moderate resistance to r. solani anastomosis group 8 identified in medicago truncatula. the activity of the ethylene- and jasmonate-respo ...201020713618
palmate-like pentafoliata1 encodes a novel cys(2)his(2) zinc finger transcription factor essential for compound leaf morphogenesis in medicago truncatula.as the primary site for photosynthetic carbon fixation and the interface between plants and the environment, plant leaves play a key role in plant growth, biomass production and survival, and global carbon and oxygen cycles. leaves can be simple with a single blade or compound with multiple units of blades known as leaflets. in a palmate-type compound leaf, leaflets are clustered at the tip of the leaf. in a pinnate-type compound leaf, on the other hand, leaflets are placed on a rachis in distan ...201020724826
comparative proteomics of yeast-elicited medicago truncatula cell suspensions reveals induction of isoflavonoid biosynthesis and cell wall modifications.the temporal proteome response of medicago truncatula suspension cell cultures to yeast elicitation (which mimics fungal infection) was investigated using two-dimensional polyacrylamide gel electrophoresis (2-de) and nanoliquid chromatography coupled to tandem mass spectrometry (nano lc-ms/ms). reproducibility of 2-de was assessed using the number of the visualized protein spots and spot volume. average coefficient of variation was determined to be less than 6% for the number of spots and around ...201020853911
how many peas in a pod? legume genes responsible for mutualistic symbioses underground.the nitrogen-fixing symbiosis between legume plants and rhizobium bacteria is the most prominent plant-microbe endosymbiotic system and, together with mycorrhizal fungi, has critical importance in agriculture. the introduction of two model legume species, lotus japonicus and medicago truncatula, has enabled us to identify a number of host legume genes required for symbiosis. a total of 26 genes have so far been cloned from various symbiotic mutants of these model legumes, which are involved in r ...201020660226
recombinant artificial forisomes provide ample quantities of smart biomaterials for use in technical devices.forisomes are mechanoproteins that undergo atp-independent contraction-expansion cycles triggered by divalent cations, ph changes, and electrical stimuli. although native forisomes from medicago truncatula comprise a number of subunits encoded by separate genes, here we show that at least two of those subunits (mtseo1 and mtseo4) can assemble into homomeric forisome bodies that are functionally similar to their native, multimeric counterparts. we expressed these subunits in plants and yeast, res ...201020665019
host and nonhost resistance in medicago-colletotrichum interactions.medicago truncatula lines resistant (a17) or susceptible (f83005.5) to the alfalfa pathogen colletotrichum trifolii were used to compare defense reactions induced upon inoculation with c. trifolii or with the nonadapted pathogens c. lindemuthianum and c. higginsianum. nonadapted colletotrichum spp. induced a hypersensitive response (hr)-like reaction similar to the one induced during the host-incompatible interaction. molecular analyses indicated an induction of pr10 and chalcone synthase genes ...201020687801
multiple distinct small rnas originate from the same microrna precursors.micrornas (mirnas), which originate from precursor transcripts with stem-loop structures, are essential gene expression regulators in eukaryotes.201020696037
characterization of the medicago truncatula cell wall proteome in cell suspension culture upon elicitation and suppression of plant defense.in addition to establishing methods for proteome analysis of cell wall proteins (cwps) for the model plant medicago truncatula, this work highlights the presence of several protein classes in cell culture. using a combination of two-dimensional gel electrophoresis (2d-page) and/or liquid chromatography-tandem mass spectrometry (lc-ms/ms), we established the proteome reference map of m. truncatula cell wall proteins. cwps extracted from purified cell wall fragments resulted in the identification ...201020801546
stimulation of defense reactions in medicago truncatula by antagonistic lipopeptides from paenibacillus sp. strain b2.with the aim of obtaining new strategies to control plant diseases, we investigated the ability of antagonistic lipopolypeptides (paenimyxin) from paenibacillus sp. strain b2 to elicit hydrogen peroxide (h₂o₂) production and several defense-related genes in the model legume medicago truncatula. for this purpose, m. truncatula cell suspensions were used and a pathosystem between m. truncatula and fusarium acuminatum was established. in m. truncatula cell cultures, the induction of h₂o₂ reached a ...201020870792
expression pattern suggests a role of mir399 in the regulation of the cellular response to local pi increase during arbuscular mycorrhizal symbiosis.many plants improve their phosphate (pi) availability by forming mutualistic associations with arbuscular mycorrhizal (am) fungi. pi-repleted plants are much less colonized by am fungi than pi-depleted plants. this indicates a link between plant pi signaling and am development. micrornas (mir) of the 399 family are systemic pi-starvation signals important for maintenance of pi homeostasis in arabidopsis thaliana and might also qualify as signals regulating am development in response to pi availa ...201020521954
transcription factor profiling leading to the identification of putative transcription factors involved in the medicago truncatula-uromyces striatus interaction.understanding the host response to uromyces sp., the causal agent of rust in many crop species, is crucial in elucidating the specific biology of rust resistance. in an attempt to unravel the medicago truncatula-u. striatus interaction, we performed a global analysis of transcription factor (tf) expression in resistant and susceptible accessions of the model plant m. truncatula during infection with u. striatus. for this purpose, an established qpcr platform was applied, consisting of specific p ...201020582581
non-protein-coding rnas and their interacting rna-binding proteins in the plant cell nucleus.the complex responses of eukaryotic cells to external factors are governed by several transcriptional and post-transcriptional processes. several of them occur in the nucleus and have been linked to the action of non-protein-coding rnas (or npcrnas), both long and small npcrnas, that recently emerged as major regulators of gene expression. regulatory npcrnas acting in the nucleus include silencing-related rnas, intergenic npcrnas, natural antisense rnas, and other aberrant rnas resulting from th ...201020603381
medicago truncatula proteomics.legumes (fabaceae) are unique in their ability to enter into an elaborate symbiosis with nitrogen-fixing rhizobial bacteria. rhizobia-legume (rl) symbiosis represents one of the most productive nitrogen-fixing systems and effectively renders the host plants to be more or less independent of other nitrogen sources. due to high protein content, legumes are among the most economically important crop families. beyond that, legumes consist of over 16,000 species assigned to 650 genera. in most cases, ...201020621211
proteomic analysis of medicago truncatula root plastids.despite the recognized importance of non-photosynthetic plastids in a wide array of plant processes, the root plastid proteome of soil-grown plants still remains to be explored. in this study, we used a protocol allowing the isolation of medicago truncatula root plastids with sufficient protein recovery and purity for their subsequent in-depth analysis by nanoscale capillary lc-ms/ms. besides providing the first picture of a root plastid proteome, the results obtained highlighted the identificat ...201020336678
effects of water deficit stress on growth, water relations and osmolyte accumulation in medicago truncatula and m. laciniata populations.the effects of water stress were investigated in two tunisian medicago truncatula populations collected from arid (mt-173) and sub-humid (mt-664) climates and two tunisian m. laciniata populations originating from arid (ml-173) and semi-arid (ml-345) regions. after a pre-treatment phase (24 days after sowing, das) of watering at 100% of field capacity (fc), the plants were either irrigated at 100% fc or at only 33% fc. after 12 days of treatment (36 das), one lot of dehydrated plants was rewater ...201020338538
nitrogen fixation persists under conditions of salt stress in transgenic medicago truncatula plants expressing a cyanobacterial flavodoxin.several recent studies have demonstrated that the expression of a cyanobacterial flavodoxin in plants can provide tolerance to a wide range of environmental stresses. indeed, this strategy has been proposed as a potentially powerful biotechnological tool to generate multiple-tolerant crops. to determine whether flavodoxin expression specifically increased tolerance to salt stress and whether it might also preserve legume nitrogen fixation under saline conditions, the flavodoxin gene was introduc ...201020353403
signaling ltps: a new plant ltps sub-family?numerous plant non specific lipid transfer protein (nsltps) have been characterized for their antimicrobial activity, suggesting for these proteins a direct role in the protection against pathogenic microorganisms. another group of ltps seems to be involved in structural events in the extracellular matrix through binding and transport of hydrophobic molecules. more recently, some ltps putatively involved in the symbiotic interaction between legumes and rhizobia have been identified. we investiga ...201020404561
phymatotrichum (cotton) root rot caused by phymatotrichopsis omnivora: retrospects and prospects.phymatotrichum (cotton or texas) root rot is caused by the soil-borne fungus phymatotrichopsis omnivora (duggar) hennebert. the broad host range of the fungus includes numerous crop plants, such as alfalfa and cotton. together with an overview of existing knowledge, this review is aimed at discussing the recent molecular and genomic approaches that have been undertaken to better understand the disease development at the molecular level with the ultimate goal of developing resistant germplasm. ta ...201020447281
genomic and coexpression analyses predict multiple genes involved in triterpene saponin biosynthesis in medicago truncatula.saponins, an important group of bioactive plant natural products, are glycosides of triterpenoid or steroidal aglycones (sapogenins). saponins possess many biological activities, including conferring potential health benefits for humans. however, most of the steps specific for the biosynthesis of triterpene saponins remain uncharacterized at the molecular level. here, we use comprehensive gene expression clustering analysis to identify candidate genes involved in the elaboration, hydroxylation, ...201020348429
the response to nitric oxide of the nitrogen-fixing symbiont sinorhizobium meliloti.nitric oxide (no) is crucial in animal- and plant-pathogen interactions, during which it participates in host defense response and resistance. indications for the presence of no during the symbiotic interaction between the model legume medicago truncatula and its symbiont sinorhizobium meliloti have been reported but the role of no in symbiosis is far from being elucidated. our objective was to understand the role or roles played by no in symbiosis. as a first step toward this goal, we analyzed ...201020459314
improvement of phosphate solubilization and medicago plant yield by an indole-3-acetic acid-overproducing strain of sinorhizobium meliloti.nitrogen (n) and phosphorus (p) are the most limiting factors for plant growth. some microorganisms improve the uptake and availability of n and p, minimizing chemical fertilizer dependence. it has been published that the rd64 strain, a sinorhizobium meliloti 1021 strain engineered to overproduce indole-3-acetic acid (iaa), showed improved nitrogen fixation ability compared to the wild-type 1021 strain. here, we present data showing that rd64 is also highly effective in mobilizing p from insolub ...201020511434
backbone-free transformation of barrel medic (medicago truncatula) with a medicago-derived transfer dna.in the present work, agrobacterium tumefaciens-mediated genetic transformation of the model legume medicago truncatula gaertn. (barrel medic) was carried out using the psim843 vector that contains a medicago-derived transfer dna, delineated by a 25-bp sequence homologous to bacterial t-dna borders. the transfer dna contains an expression cassette for the nptii (neomycin phosphotransferase) gene and is flanked by an expression cassette for the backbone integration marker gene ipt (isopentenyl tra ...201020571798
plant peptides govern terminal differentiation of bacteria in symbiosis.legume plants host nitrogen-fixing endosymbiotic rhizobium bacteria in root nodules. in medicago truncatula, the bacteria undergo an irreversible (terminal) differentiation mediated by hitherto unidentified plant factors. we demonstrated that these factors are nodule-specific cysteine-rich (ncr) peptides that are targeted to the bacteria and enter the bacterial membrane and cytosol. obstruction of ncr transport in the dnf1-1 signal peptidase mutant correlated with the absence of terminal bacteri ...201020185722
a nodule-specific protein secretory pathway required for nitrogen-fixing symbiosis.the nitrogen-fixing symbiosis between sinorhizobium meliloti and its leguminous host plant medicago truncatula occurs in a specialized root organ called the nodule. bacteria that are released into plant cells are surrounded by a unique plant membrane compartment termed a symbiosome. we found that in the symbiosis-defective dnf1 mutant of m. truncatula, bacteroid and symbiosome development are blocked. we identified the dnf1 gene as encoding a subunit of a signal peptidase complex that is highly ...201020185723
partner choice in medicago truncatula-sinorhizobium symbiosis.in nitrogen-fixing symbiosis, plant sanctions against ineffective bacteria have been demonstrated in previous studies performed on soybean and yellow bush lupin, both developing determinate nodules with bradyrhizobium sp. strains. in this study, we focused on the widely studied symbiotic association medicago truncatula-sinorhizobium meliloti, which forms indeterminate nodules. using two strains isolated from the same soil and displaying different nitrogen fixation phenotypes on the same fixed pl ...201020200033
differentiation of symbiotic cells and endosymbionts in medicago truncatula nodulation are coupled to two transcriptome-switches.the legume plant medicago truncatula establishes a symbiosis with the nitrogen-fixing bacterium sinorhizobium meliloti which takes place in root nodules. the formation of nodules employs a complex developmental program involving organogenesis, specific cellular differentiation of the host cells and the endosymbiotic bacteria, called bacteroids, as well as the specific activation of a large number of plant genes. by using a collection of plant and bacterial mutants inducing non-functional, fix(-) ...201020209049
infection-specific activation of the medicago truncatula enod11 early nodulin gene promoter during actinorhizal root nodulation.the mtenod11 gene from medicago truncatula is widely used as an early infection-related molecular marker for endosymbiotic associations involving both rhizobia and arbuscular mycorrhizal fungi. in this article, heterologous expression of the mtenod11 promoter has been studied in two actinorhizal trees, casuarina glauca and allocasuarina verticillata. transgenic c. glauca and a. verticillata expressing a promtenod11::beta-glucuronidase (gus) fusion were generated and the activation of the transge ...201020459313
suppression of hypernodulation in soybean by a leaf-extracted, nark- and nod factor-dependent, low molecular mass fraction.*legumes regulate the number of nodules they form via a process called autoregulation of nodulation (aon). this involves a shoot-derived inhibitor (sdi) molecule that is synthesized in the shoots and is transported down to the roots where it inhibits further nodule development. *to characterize sdi, we developed a novel feeding bioassay. this involved feeding aqueous leaf extracts directly into the petiole of hypernodulating and supernodulating nark mutant plants of glycine max (soybean). these ...201020100211
cloning and characterization of a functional flavanone-3ß-hydroxylase gene from medicago truncatula.as a key enzyme in the biosynthesis of flavonols, anthocyanidins and proanthocyanidins, flavanone-3ß-hydroxylase (f3h) plays very important roles in plant stress response. a putative flavanone-3ß-hydroxylase gene from medicago truncatula (mtf3h), a model legume species, was identified from a bio-data analysis platform. it was speculated to be induced by salt stress based on the outcomes of the analysis platform. the complementary dna (cdna) consists of 1499 bp with an open reading frame (orf) of ...201019888675
red clover coumarate 3'-hydroxylase (cyp98a44) is capable of hydroxylating p-coumaroyl-shikimate but not p-coumaroyl-malate: implications for the biosynthesis of phaselic acid.red clover (trifolium pratense) leaves accumulate several mumol of phaselic acid [2-o-caffeoyl-l-malate] per gram fresh weight. post-harvest oxidation of such o-diphenols to o-quinones by endogenous polyphenol oxidases (ppo) prevents breakdown of forage protein during storage. forages like alfalfa (medicago sativa) lack both foliar ppo activity and o-diphenols. consequently, breakdown of their protein upon harvest and storage results in economic losses and release of excess nitrogen into the env ...201019921248
identification of flavone phytoalexins and a pathogen-inducible flavone synthase ii gene (sbfnsii) in sorghum.following inoculation with the anthracnose pathogen colletotrichum sublineolum, seedlings of the sorghum resistant cultivar sc748-5 showed more rapid and elevated accumulation of luteolin than the susceptible cultivar btx623. on the other hand, apigenin was the major flavone detected in infected btx623 seedlings. luteolin was demonstrated to show stronger inhibition of spore germination of c. sublineolum than apigenin. because of their pathogen-inducible and antifungal nature, both flavone aglyc ...201020007684
a complex genetic network involving a broad-spectrum locus and strain-specific loci controls resistance to different pathotypes of aphanomyces euteiches in medicago truncatula.a higher understanding of genetic and genomic bases of partial resistance in plants and their diversity regarding pathogen variability is required for a more durable management of resistance genetic factors in sustainable cropping systems. in this study, we investigated the diversity of genetic factors involved in partial resistance to aphanomyces euteiches, a very damaging pathogen on pea and alfalfa, in medicago truncatula. a mapping population of 178 recombinant inbred lines, from the cross f ...201020012740
the mtsnf4b subunit of the sucrose non-fermenting-related kinase complex connects after-ripening and constitutive defense responses in seeds of medicago truncatula.dormant seeds are capable of remaining alive in the hydrated state for extended periods of time without losing vigor, until environmental cues or after-ripening result in the release of dormancy. here, we investigated the possible role of the regulatory subunit of the sucrose non-fermenting-related kinase complex, mtsnf4b, in dormancy of medicago truncatula seeds. expression of mtsnf4b and its involvement in a high-molecular-weight complex are found in dormant seeds, whereas imbibition of fully ...201020015062
plant flotillins are required for infection by nitrogen-fixing bacteria.to establish compatible rhizobial-legume symbioses, plant roots support bacterial infection via host-derived infection threads (its). here, we report the requirement of plant flotillin-like genes (flots) in sinorhizobium meliloti infection of its host legume medicago truncatula. flotillins in other organisms have roles in viral pathogenesis, endocytosis, and membrane shaping. we identified seven flot genes in the m. truncatula genome and show that two, flot2 and flot4, are strongly up-regulated ...201020018678
a novel rna-binding peptide regulates the establishment of the medicago truncatula-sinorhizobium meliloti nitrogen-fixing symbiosis.plants use a variety of small peptides for cell to cell communication during growth and development. leguminous plants are characterized by their ability to develop nitrogen-fixing nodules via an interaction with symbiotic bacteria. during nodule organogenesis, several so-called nodulin genes are induced, including large families that encode small peptides. using a three-hybrid approach in yeast cells, we identified two new small nodulins, mtsnarp1 and mtsnarp2 (for small nodulin acidic rna-bind ...201020042020
presence of three mycorrhizal genes in the common ancestor of land plants suggests a key role of mycorrhizas in the colonization of land by plants.*the colonization of land by plants fundamentally altered environmental conditions on earth. plant-mycorrhizal fungus symbiosis likely played a key role in this process by assisting plants to absorb water and nutrients from soil. *here, in a diverse set of land plants, we investigated the evolutionary histories and functional conservation of three genes required for mycorrhiza formation in legumes and rice (oryza sativa), dmi1, dmi3 and ipd3. *the genes were isolated from nearly all major plant ...201020059702
characterization and expression analysis of medicago truncatula rop gtpase family during the early stage of symbiosis.rops (rho-related gtpases of plants) are small gtpases that are plant-specific signaling proteins. they act as molecular switches in a variety of developmental processes. in this study, seven cdna clones coding for rop gtpases have been isolated in medicago truncatula, and conserved and divergent domains are identified in these predicted mtrop proteins. phylogenetic analysis has indicated that mtrops are distributed into groups ii, iii, iv but group i. mtrop genes are expressed in various tissue ...201020590994
sinorhizobium meliloti 1021 loss-of-function deletion mutation in chvi and its phenotypic characteristics.bacterial two-component regulatory systems (tcs) are common components of complex regulatory networks and cascades. in sinorhizobium meliloti, the tcs exos/chvi controls exopolysaccharide succinoglycan production and flagellum biosynthesis. although this system plays a crucial role in establishing the symbiosis between s. meliloti and its host plant, it is not well characterized. attempts to generate complete loss-of-function mutations in either exos or chvi in s. meliloti have been unsuccessful ...201020064059
s-glycoprotein-like protein regulates defense responses in nicotiana plants against ralstonia solanacearum.rsrga4 (for ralstonia solanacearum-responsive gene a4) encodes a polypeptide similar to s-locus glycoprotein (sgp) from brassica rapa and sgp-like proteins from ipomoea trifida and medicago truncatula. therefore, we designated rsrga4 as ntsglp (for nicotiana tabacum sgp-like protein) and nbsglp (its nicotiana benthamiana ortholog). nbsglp is expressed in root, leaf, petal, gynoecium, and stamen. expression of nbsglp was strongly induced by inoculation with an avirulent strain of r. solanacearum ...201020118275
a remorin protein interacts with symbiotic receptors and regulates bacterial infection.remorin proteins have been hypothesized to play important roles during cellular signal transduction processes. induction of some members of this multigene family has been reported during biotic interactions. however, no roles during host-bacteria interactions have been assigned to remorin proteins until now. we used root nodule symbiosis between medicago truncatula and sinorhizobium meliloti to study the roles of a remorin that is specifically induced during nodulation. here we show that this ol ...201020133878
site and plant species are important determinants of the methylobacterium community composition in the plant phyllosphere.the plant phyllosphere constitutes a habitat for numerous microorganisms; among them are members of the genus methylobacterium. owing to the ubiquitous occurrence of methylobacteria on plant leaves, they represent a suitable target for studying plant colonization patterns. the influence of the factor site, host plant species, time and the presence of other phyllosphere bacteria on methylobacterium community composition and population size were evaluated in this study. leaf samples were collected ...201020164863
role of the sinorhizobium meliloti global regulator hfq in gene regulation and symbiosis.the rna-binding protein hfq is a global regulator which controls diverse cellular processes in bacteria. to begin understanding the role of hfq in the sinorhizobium meliloti-medicago truncatula nitrogen-fixing symbiosis, we defined free-living and symbiotic phenotypes of an hfq mutant. over 500 transcripts were differentially accumulated in the hfq mutant of s. meliloti rm1021 when grown in a shaking culture. consistent with transcriptome-wide changes, the hfq mutant displayed dramatic alteratio ...201020192823
vapyrin, a gene essential for intracellular progression of arbuscular mycorrhizal symbiosis, is also essential for infection by rhizobia in the nodule symbiosis of medicago truncatula.intracellular invasion of root cells is required for the establishment of successful endosymbioses in legumes of both arbuscular mycorrhizal (am) fungi and rhizobial bacteria. in both interactions a requirement for successful entry is the activation of a common signalling pathway that includes five genes required to generate calcium oscillations and two genes required for the perception of the calcium response. recently, it has been discovered that in medicago truncatula, the vapyrin (vpy) gene ...201021223389
evidence that the exoh gene of sinorhizobium meliloti does not appear to influence symbiotic effectiveness with medicago truncatula 'jemalong a17'.the purpose of this study was to identify strains of sinorhizobium meliloti that formed either an effective or completely ineffective symbiosis with medicago truncatula l. 'jemalong a17' and, subsequently, to determine whether differences existed between their exoh genes. sinorhizobium meliloti tii7 and a5 formed an effective and ineffective symbiosis with m. truncatula 'jemalong a17', respectively. using a multilocus sequence typing method, both strains were shown to have chromosomes identical ...201021164569
both plant and bacterial nitrate reductases contribute to nitric oxide production in medicago truncatula nitrogen-fixing nodules.nitric oxide (no) is a signaling and defense molecule of major importance in living organisms. in the model legume medicago truncatula, no production has been detected in the nitrogen fixation zone of the nodule, but the systems responsible for its synthesis are yet unknown and its role in symbiosis is far from being elucidated. in this work, using pharmacological and genetic approaches, we explored the enzymatic source of no production in m. truncatula-sinorhizobium meliloti nodules under normo ...201021139086
jasmonate biosynthesis in legume and actinorhizal nodules.jasmonic acid (ja) is a plant signalling compound that has been implicated in the regulation of mutualistic symbioses. in order to understand the spatial distribution of ja biosynthetic capacity in nodules of two actinorhizal species, casaurina glauca and datisca glomerata, and one legume, medicago truncatula, we determined the localization of allene oxide cyclase (aoc) which catalyses a committed step in ja biosynthesis. in all nodule types analysed, aoc was detected exclusively in uninfected c ...201020964693
the medicago truncatula e3 ubiquitin ligase pub1 interacts with the lyk3 symbiotic receptor and negatively regulates infection and nodulation.lyk3 is a lysin motif receptor-like kinase of medicago truncatula, which is essential for the establishment of the nitrogen-fixing, root nodule symbiosis with sinorhizobium meliloti. lyk3 is a putative receptor of s. meliloti nod factor signals, but little is known of how it is regulated and how it transduces these symbiotic signals. in a screen for lyk3-interacting proteins, we identified m. truncatula plant u-box protein 1 (pub1) as an interactor of the kinase domain. in planta, both proteins ...201020971894
mtnoa1/rif1 modulates medicago truncatula-sinorhizobium meliloti nodule development without affecting its nitric oxide content.atnoa1/rif1 (formerly referred to as atnos1) has been shown to modulate nitric oxide (no) content in arabidopsis. as no generation in the legume-rhizobium symbiosis has been shown, the involvement of an atnoa1/rif1 orthologue from medicago truncatula (mtnoa1/rif1) during its symbiotic interaction with sinorhizobium meliloti has been studied. the expression of mtnoa1/rif1 appeared to occur mainly in nodule vascular bundles and the meristematic zone. using an rna interference strategy, transgenic ...201021071678
rhizoregnet-a database of rhizobial transcription factors and regulatory networks.sinorhizobium meliloti is a symbiotic soil bacterium that forms nitrogen-fixing nodules on roots of leguminous plants, including medicago truncatula (barrel medic), and m. sativa (alfalfa). the sinorhizobium-medicago symbiosis is an important symbiosis model system. knowledge gained from this system can be extended to other agriculturally important "rhizobial" symbioses. since the publication of the s. meliloti genome in 2001, many new genetic, biochemical and physiological data have been genera ...201021087643
antioxidant gene-enzyme responses in medicago truncatula genotypes with different degree of sensitivity to salinity.antioxidant responses and nodule function of medicago truncatula genotypes differing in salt tolerance were studied. salinity effects on nodules were analysed on key nitrogen fixation proteins such as nitrogenase and leghaemoglobin as well as estimating lipid peroxidation levels, and were found more dramatic in the salt-sensitive genotype. antioxidant enzyme assays for catalase (cat, ec 1.11.1.6), superoxide dismutase (ec 1.15.1.1), ascorbate peroxidase (ec 1.11.1.11) and guaiacol peroxidase (ec ...201021114673
abscopal signals mediated bio-effects in low-energy ion irradiated medicago truncatula seeds.the mutagenic effects of low-energy ions have been identified by genetic studies for decades. due to the short penetration distance of ions, however, the underlying mechanism(s) is still not quite clarified. recently, increasing data have been accumulated concerning the existence and manifestation of radiation induced bystander/abscopal effects in vivo in the whole-organism environment. in this study, the bio-effects and the preliminary mechanisms of low energy ion beam irradiation on medicago t ...201021116098
functional expression and purification of cyp93c20，a plant membrane-associated cytochrome p450 from medicago truncatula.plants possess very large numbers of biosynthetic cytochrome p450 enzymes. in spite of the importance of these enzymes for the synthesis of bioactive plant secondary metabolites, only two plant p450 structures has been obtained to date. isoflavone synthase (ifs) is a membrane-associated cytochrome p450 enzyme catalyzing the entry-point reaction into isoflavonoid biosynthesis. ifs from the model legume medicago truncatula (cyp93c20) was engineered by deleting the membrane-spanning domain and inse ...201021138770
a medicago truncatula nadph oxidase is involved in symbiotic nodule functioning.the plant plasma membrane-localized nadph oxidases, known as respiratory burst oxidase homologues (rbohs), appear to play crucial roles in plant growth and development. they are involved in important processes, such as root hair growth, plant defence reactions and abscisic acid signalling. using sequence similarity searches, we identified seven putative rboh-encoding genes in the medicago truncatula genome. a phylogenetic reconstruction showed that rboh gene duplications occurred in legume speci ...201021155825
genetic dissection of rhizobium-induced infection and nodule organogenesis in pea based on enod12a and enod5 expression analysis.in legumes, perception of rhizobial lipochitooligosacharide-based molecules (nod factors) and subsequent signal transduction triggers transcription of plant symbiosis-specific genes (early nodulins). we present genetic dissection of nod factor-controlled processes in pisum sativum using two early nodulin genes psenod12a and psenod5, that are differentially up-regulated during symbiosis. a novel set of non-nodulating pea mutants in fourteen loci was examined, among which seven loci are not descri ...201021309975
environmental regulation of lateral root emergence in medicago truncatula requires the hd-zip i transcription factor hb1.the adaptation of root architecture to environmental constraints is a major agricultural trait, notably in legumes, the third main crop worldwide. this root developmental plasticity depends on the formation of lateral roots (lrs) emerging from primary roots. in the model legume medicago truncatula, the hd-zip i transcription factor hb1 is expressed in primary and lateral root meristems and induced by salt stress. constitutive expression of hb1 in m. truncatula roots alters their architecture, wh ...201020675575
the compact root architecture1 gene regulates lignification, flavonoid production, and polar auxin transport in medicago truncatula.the root system architecture is crucial to adapt plant growth to changing soil environmental conditions and consequently to maintain crop yield. in addition to root branching through lateral roots, legumes can develop another organ, the nitrogen-fixing nodule, upon a symbiotic bacterial interaction. a mutant, cra1, showing compact root architecture was identified in the model legume medicago truncatula. cra1 roots were short and thick due to defects in cell elongation, whereas densities of later ...201020522723
two medicago truncatula half-abc transporters are essential for arbuscule development in arbuscular mycorrhizal symbiosis.in the symbiotic association of plants and arbuscular mycorrhizal (am) fungi, the fungal symbiont resides in the root cortical cells where it delivers mineral nutrients to its plant host through branched hyphae called arbuscules. here, we report a medicago truncatula mutant, stunted arbuscule (str), in which arbuscule development is impaired and am symbiosis fails. in contrast with legume symbiosis mutants reported previously, str shows a wild-type nodulation phenotype. str was identified by pos ...201020453115
cle peptides control medicago truncatula nodulation locally and systemically.the clavata3/embryo-surrounding region (cle) peptides control the fine balance between proliferation and differentiation in plant development. we studied the role of cle peptides during indeterminate nodule development and identified 25 mtcle peptide genes in the medicago truncatula genome, of which two genes, mtcle12 and mtcle13, had nodulation-related expression patterns that were linked to proliferation and differentiation. mtcle13 expression was up-regulated early in nodule development. a hi ...201020348212
comparison of developmental and stress-induced nodule senescence in medicago truncatula.mature indeterminate medicago truncatula nodules are zonated with an apical meristem, an infection zone, a fixation zone with nitrogen-fixing bacteroids, and a "developmental" senescence zone that follows nodule growth with a conical front originating in the center of the fixation zone. in nitrogen-fixing cells, senescence is initiated coincidently with the expression of a family of conserved cysteine proteases that might be involved in the degradation of symbiotic structures. environmental stre ...201020081044
knockdown of cell division cycle16 reveals an inverse relationship between lateral root and nodule numbers and a link to auxin in medicago truncatula.the postembryonic development of lateral roots and nodules is a highly regulated process. recent studies suggest the existence of cross talk and interdependency in the growth of these two organs. although plant hormones, including auxin and cytokinin, appear to be key players in coordinating this cross talk, very few genes that cross-regulate root and nodule development have been uncovered so far. this study reports that a homolog of cell division cycle16 (cdc16), a core component of the anaphas ...200919789288
live-cell imaging reveals periarbuscular membrane domains and organelle location in medicago truncatula roots during arbuscular mycorrhizal symbiosis.in the arbuscular mycorrhizal symbiosis, the fungal symbiont colonizes root cortical cells, where it establishes differentiated hyphae called arbuscules. as each arbuscule develops, the cortical cell undergoes a transient reorganization and envelops the arbuscule in a novel symbiosis-specific membrane, called the periarbuscular membrane. the periarbuscular membrane, which is continuous with the plant plasma membrane of the cortical cell, is a key interface in the symbiosis; however, relatively l ...200919692536
mere1, a low-copy-number copia-type retroelement in medicago truncatula active during tissue culture.we have identified an active medicago truncatula copia-like retroelement called medicago retroelement1-1 (mere1-1) as an insertion in the symbiotic nsp2 gene. mere1-1 belongs to a low-copy-number family in the sequenced medicago genome. these copies are highly related, but only three of them have a complete coding region and polymorphism exists between the long terminal repeats of these different copies. this retroelement family is present in all m. truncatula ecotypes tested but also in other l ...200919656907
lin, a novel type of u-box/wd40 protein, controls early infection by rhizobia in legumes.the formation of a nitrogen-fixing nodule requires the coordinated development of rhizobial colonization and nodule organogenesis. based on its mutant phenotype, lumpy infections (lin), lin functions at an early stage of the rhizobial symbiotic process, required for both infection thread growth in root hair cells and the further development of nodule primordia. we show that spontaneous nodulation activated by the calcium- and calmodulin-dependent protein kinase is independent of lin; thus, lin i ...200919776163
biotic and abiotic stimulation of root epidermal cells reveals common and specific responses to arbuscular mycorrhizal fungi.during arbuscular mycorrhizal (am) colonization, a focal accumulation of organelles occurs in root epidermal cells, prior to fungal penetration, beneath adhering hyphopodia. this is followed by the appearance of the prepenetration apparatus (ppa), a transcellular column of cytoplasm connected to the nucleus and rich in cytoskeleton and secretory endomembranes. this apparatus appears to be responsible for the construction of an apoplastic compartment that confines the fungus within the cell lumen ...200919151131
a novel plant leucine-rich repeat receptor kinase regulates the response of medicago truncatula roots to salt stress.in plants, a diverse group of cell surface receptor-like protein kinases (rlks) plays a fundamental role in sensing external signals to regulate gene expression. roots explore the soil environment to optimize their growth via complex signaling cascades, mainly analyzed in arabidopsis thaliana. however, legume roots have significant physiological differences, notably their capacity to establish symbiotic interactions. these major agricultural crops are affected by environmental stresses such as s ...200919244136
a wd40 repeat protein from medicago truncatula is necessary for tissue-specific anthocyanin and proanthocyanidin biosynthesis but not for trichome development.wd40 repeat proteins regulate biosynthesis of anthocyanins, proanthocyanidins (pas), and mucilage in the seed and the development of trichomes and root hairs. we have cloned and characterized a wd40 repeat protein gene from medicago truncatula (mtwd40-1) via a retrotransposon-tagging approach. deficiency of mtwd40-1 expression blocks accumulation of mucilage and a range of phenolic compounds, including pas, epicatechin, other flavonoids, and benzoic acids, in the seed, reduces epicatechin levels ...200919710231
the association of homeobox gene expression with stem cell formation and morphogenesis in cultured medicago truncatula.somatic embryogenesis (se) is induced in vitro in medicago truncatula 2ha by auxin and cytokinin but rarely in wild type jemalong. the putative wuschel (mtwus), clavata3 (mtclv3) and the wuschel-related homeobox gene wox5 (mtwox5) were investigated in m. truncatula (mt) and identified by the similarity to arabidopsis wus, clv3 and wox5 in amino acid sequence, phylogeny and in planta and in vitro expression patterns. mtwus was induced throughout embryogenic cultures by cytokinin after 24-48 h and ...200919639337
expression of the somatic embryogenesis receptor-like kinase1 (serk1) gene is associated with developmental change in the life cycle of the model legume medicago truncatula.somatic embryogenesis receptor-like kinase (serk) genes have been demonstrated to play a role in somatic embryogenesis in several plant species. as more is learnt about these genes, the view of their role in plant development has broadened. the medicago truncatula mtserk1 gene has been associated with somatic embryogenesis and in vitro root formation. in order to study the role of mtserk1 in development further, the mtserk1 promoter sequence has been isolated and cloned into a promoter-gus analy ...200919305022
medicago truncatula and glomus intraradices gene expression in cortical cells harboring arbuscules in the arbuscular mycorrhizal symbiosis.most vascular flowering plants have the capacity to form symbiotic associations with arbuscular mycorrhizal (am) fungi. the symbiosis develops in the roots where am fungi colonize the root cortex and form arbuscules within the cortical cells. arbuscules are enveloped in a novel plant membrane and their establishment requires the coordinated cellular activities of both symbiotic partners. the arbuscule-cortical cell interface is the primary functional interface of the symbiosis and is of central ...200919161626
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