Publications

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[the effect of common leaf spot (pseudopeziza medicaginis (lib.) sacc.) and leaf spot (stemphylium botryosum wallr.; phoma medicaginis malbr. et roum.) on the co2 assimilation by the leaves of alfalfa (medicago sativa l.)]. 19695396112
comparative toxicity of allelochemicals and their enzymatic oxidation products to maize fungal pathogens, emphasizing fusarium graminearum.a series of stable quinones and their precursors, and enzymatic oxidation products of plant allelochemicals were tested for their effect on maize fungal pathogens, primarily fusarium graminearum. benzoquinone was typically significantly more toxic than hydroquinone, while 1,2-naphthoquinone was typically significantly more toxic than 1,2-dihydroxynaphthalene. aspergillus flavus was the most resistant fungus to these compounds, while phoma medicaginis was the most susceptible. applying tyrosinase ...19979496376
a comparison of constitutive promoters for expression of transgenes in alfalfa (medicago sativa).the activity of constitutive promoters was compared in transgenic alfalfa plants using two marker genes. three promoters, the 35s promoter from cauliflower mosaic virus (camv), the cassava vein mosaic virus (csvmv) promoter, and the sugarcane bacilliform badnavirus (scbv) promoter were each fused to the beta-glucuronidase (gusa) gene. the highest gus enzyme activity was obtained using the csvmv promoter and all alfalfa cells assayed by in situ staining had high levels of enzyme activity. the 35s ...200415517994
two alternative recessive quantitative trait loci influence resistance to spring black stem and leaf spot in medicago truncatula.knowledge of the genetic basis of plant resistance to necrotrophic pathogens is incomplete and has been characterised in relatively few pathosystems. in this study, the cytology and genetics of resistance to spring black stem and leaf spot caused by phoma medicaginis, an economically important necrotrophic pathogen of medicago spp., was examined in the model legume m. truncatula.200818366746
identification of sources of resistance to phoma medicaginis isolates in medicago truncatula sardi core collection accessions, and multigene differentiation of isolates.abstract phoma medicaginis is a necrotrophic fungal pathogen, commonly found infecting the annual medic medicago truncatula. to differentiate eight p. medicaginis isolates, five gene regions were examined: actin, beta-tubulin, calmodulin, translation elongation factor 1-alpha (ef-1alpha), and the internal transcribed spacer ribosomal dna. sequence comparisons showed that specimens isolated from m. truncatula in western australia formed a group that was consistently different from, but allied to, ...200618943665
a new species of phoma causes ascochyta blight symptoms on field peas (pisum sativum) in south australia.phoma koolunga sp. nov. is described, having been isolated from ascochyta blight lesions on field pea (pisum sativum) in south australia. the species is described morphologically and sequences of the internal transcribed spacer region compared with those of the accepted pathogens causing ascochyta blight of field peas. p. koolunga was distinct from mycosphaerella pinodes (anamorph: ascochyta pinodes), phoma medicaginis var. pinodella and ascochyta pisi. under controlled conditions the symptoms o ...200919271674
comparison of cultural growth and in planta quantification of didymella pinodes, phoma koolunga and phoma medicaginis var. pinodella, causal agents of ascochyta blight on field pea (pisum sativum).the causal agents of ascochyta blight on field pea in south australia, didymella pinodes, phoma medicaginis var. pinodella and phoma koolunga, are isolated from a single plant within a crop, suggesting competition for space and nutrients. interactions among these pathogens were investigated. diameters of colonies of d. pinodes and of p. medicaginis var. pinodella were significantly reduced on pda amended with filtrate from broth cultures of p. koolunga as were diameters of colonies of d. pinodes ...201121933927
application of amplified restriction fragment length polymorphism for genetic characterization of colletotrichum pathogens of alfalfa.abstract amplified restriction fragment length polymorphism (aflp) was used to assess the levels of genomic variations among species and isolates of the genus colletotrichum. our objective was to characterize at the molecular level two alfalfa pathogens, isolates arl-nw and 57rr, which are unusually aggressive to anthracnose-resistant alfalfa cultivars and whose taxa has been uncertain based on morphological criteria. the fingerprint patterns obtained were complex but did enable us to place thes ...199718945097
interactions between the glycoalkaloids solasonine and solamargine in relation to inhibition of fungal growth.inhibition of mycelium development in phoma medicaginis and rhizoctonia solani by solamargine and solasonine generally increased with increasing ph. p. medicaginis was the more susceptible species and solamargine the more potent compound. solasonine was inactive against r. solani over the tested ph range (5-8). dose-response curves confirmed these differential effects. solamargine caused 50% growth inhibition in p. medicaginis at 60 microm (at ph 7) whereas no other treatment achieved this effec ...19947765652
effects of temperature, light, carbon and nitrogen nutrition on reproduction in phoma medicaginis. 19715111910
phoma medicaginis stimulates the induction of the octadecanoid and phenylpropanoid pathways in medicago truncatula.gene expression changes and metabolite abundances were measured during the interaction of medicago truncatula with the fungal necrotrophic pathogen phoma medicaginis in leaf tissue of susceptible and resistant accessions. over 330 genes were differentially expressed in plants infected with p. medicaginis relative to mock-inoculated plants at 12 h post-inoculation. of these, 191 were induced in either the resistant or the susceptible accession, with 143 genes repressed. expression changes were ob ...201222212347
xanthepinone, an antimicrobial polyketide from a soil fungus closely related to phoma medicaginis.the isolation, biological characterization, and structure elucidation of xanthepinone, a novel antifungal metabolite isolated from the broth of submerged cultures of a soil fungus, are described. xanthepinone inhibits the conidial germination of magnaporthe grisea (2 microg/ml), phytophthora infestans (5 microg/ml), and botrytis cinerea (10 microg/ml) while showing only weak antibacterial activity; cytotoxicity was not observed up to 50 microg/ml. molecular taxonomy revealed that the producing s ...200919795903
a diffusible factor from arbuscular mycorrhizal fungi induces symbiosis-specific mtenod11 expression in roots of medicago truncatula.using dual cultures of arbuscular mycorrhizal (am) fungi and medicago truncatula separated by a physical barrier, we demonstrate that hyphae from germinating spores produce a diffusible factor that is perceived by roots in the absence of direct physical contact. this am factor elicits expression of the nod factor-inducible gene mtenod11, visualized using a pmtenod11-gusa reporter. transgene induction occurs primarily in the root cortex, with expression stretching from the zone of root hair emerg ...200312644648
brefeldin a production by phoma medicaginis in dead pre-colonized plant tissue: a strategy for habitat conquest?phoma medicaginis was isolated as the dominant endophyte from surface-sterilized shoots of medicago sativa and m. lupulina growing outdoors. plants were either symptomless or showed signs of infection in the shape of limited lesions which sometimes contained melanized pycnidial initials. rapid colonization of host tissue and sporulation were observed within 9 d on dead plant material upon incubation in a moist chamber. such colonized material, but not freshly harvested living tissue, contained b ...200415323249
changes in the profile of flavonoid accumulation in medicago truncatula leaves during infection with fungal pathogen phoma medicaginis.medicago truncatula is a model species for the study of the unique secondary metabolism in legumes. lc/ms/ms analysis was used to identify and profile flavonoid glycoconjugates and free aglycones in leaves of m. truncatula (ecotype r108-1) infected with the fungal pathogen phoma medicaginis. use of a high resolution analyzer with a collision induced dissociation tandem mass spectrometer (cid ms/ms) permitted structural elucidation of target secondary metabolites and four new acylated flavone gly ...200919541494
genetic manipulation of isoflavone 7-o-methyltransferase enhances biosynthesis of 4'-o-methylated isoflavonoid phytoalexins and disease resistance in alfalfa.4'-o-methylation of an isoflavonoid intermediate is a key reaction in the biosynthesis of the phytoalexin medicarpin in legumes. however, isoflavone o-methyltransferase (iomt) from alfalfa converts the isoflavone daidzein to 7-o-methyl daidzein (isoformononetin) in vitro as well as in vivo in unchallenged leaves of transgenic alfalfa ectopically expressing iomt. in contrast, elicitation of iomt-overexpressing plants with cucl(2) or infecting these plants with phoma medicaginis leads to greater a ...200011006341
differentiation of the "ascochyta complex" fungi of pea by biochemical and molecular markers.isolates of three closely related pea pathogens, ascochyta pisi, ascochyta pinodes (teleomorph mycosphaerella pinodes) and phoma medicaginis var. pinodella, were compared by means of isozyme analysis and restriction fragment length polymorphisms (rflp) of amplified rdna spacers. three enzyme systems differentiated a. pisi from m. pinodes and p. m. pinodella. the internal transcribed spacers (itss) of the three fungi showed no intraspecific and very little interspecific variation after digestion ...19968821666
stress responses in alfalfa (medicago sativa l.). 15. characterization and expression patterns of members of a subset of the chalcone synthase multigene family.we have identified five different full length chalcone synthase (chs) cdna clones from a cdna library produced from transcripts isolated from an elicitor-treated alfalfa cell suspension culture. nucleotide sequence similarity between the clones varied from 88-93%. oligonucleotides based on divergent sequences in the 5'-untranslated regions of the clones could distinguish individual genes, or groups of genes, and their corresponding transcripts. developmentally regulated expression of the chs tra ...19938507827
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 ...200516006598
molecular relatedness within the "ascochyta pinodes-complex".the morphological, molecular and pathological characters of 34 isolates identified as ascochyta pinodes, a. phaseolorum, and phoma medicaginis var. pinodella were determined. initial molecular findings, based on pcr fragment size and rflps of sections of the mitochondrial genome, the rrna gene cluster and the beta-tubulin gene complex, were further investigated by sequencing of the total rrna its regions. isolates were homogenous for all characteristics determined, with the exception of conidial ...200314682458
constitutive accumulation of a resveratrol-glucoside in transgenic alfalfa increases resistance to phoma medicaginis.alfalfa (medicago sativa) was transformed with a peanut (arachis hypogaea) cdna encoding resveratrol synthase (rs) transcriptionally regulated by an enhanced cauliflower mosaic virus (camv) 35s promoter. transgenic plants accumulated a new compound, not present in wild-type or vector-transformed alfalfa, that was identified as trans-resveratrol-3-o-beta-d-glucopyranoside (rgluc) by high-pressure liquid chromatography (hplc), uv, 1h- and 13c-nuclear magnetic resonance (nmr) analyses. rgluc concen ...200010796021
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