studies of phytophthora citricola, isolated from persea americana. 19744437579
acclimation to ozone affects host/pathogen interaction and competitiveness for nitrogen in juvenile fagus sylvatica and picea abies trees infected with phytophthora a two-year phytotron study, juvenile trees of european beech (fagus sylvatica) and norway spruce (picea abies) were grown in mixture under ambient and twice ambient ozone (o3) and infected with the root pathogen phytophthora citricola. we investigated the influence of o3 on the trees' susceptibility to the root pathogen and assessed, through a 15n-labelling experiment, the impact of both treatments (o3 exposure and infection) on belowground competitiveness. the hypotheses tested were that: (1 ...200516388467
physiological changes of fagus sylvatica seedlings infected with phytophthora citricola and the contribution of its elicitin "citricolin" to pathogenesis.beech seedlings were infected with the root rot pathogen phytophthora citricola to study its impact on leaf physiology and water status. net photosynthesis rate decreased two days after inoculation in infected seedlings. in contrast, electron quantum yield of photosystem ii, leaf water potential, and total water consumption were only slightly impaired until 6 dpi. at the same time, wilt symptoms occurred on leaves. these results indicate the involvement of a mobile signal triggering the early ch ...200516388468
pattern swimming of phytophthora citricola zoospores: an example of microbial bioconvection.the genus phytophthora, belonging to the class oomycota, comprises a group of over fifty fungus-like plant pathogens in both managed and unmanaged ecosystems. a unique feature of the oomycete lifecycle is a zoosporic stage in which motile, unicellular propagules, serving as the primary agents of dispersal, are produced and released in the presence of water. in petri dish suspensions, zoospores frequently exhibit 'pattern swimming', whereby they spontaneously form concentrated swimming masses, vi ...201021354529
the avocado subgroup of phytophthora citricola constitutes a distinct species, phytophthora mengei sp. nov.isolates from avocado tree cankers have been recognized as a distinct subgroup within the p. citricola complex since 1974, both morphologically and molecularly (isozyme and amplified fragment length polymorphism [aflp] analyses). this subgroup is formally separated from p. citricola after comparative dna fingerprinting and sequence analyses of the its region, as well as by morphological examinations. this new taxon is homothallic, produces plerotic oospores with paragynous antheridia and noncadu ...200919927748
changes in susceptibility of beech (fagus sylvatica) seedlings towards phytophthora citricola under the influence of elevated atmospheric co2 and nitrogen fertilization.the growth-differentiation balance hypothesis (gdbh) predicts changes in susceptibility of plants against herbivores with changing resource availability. in the presented study we tested the validity of the gdbh for trees infected with a root pathogen. for this purpose fagus sylvatica seedlings grown under different atmospheric co(2)- and soil nitrogen regimes were infected with the root pathogen phytophthora citricola. high nitrogen supply increased total biomass of beech regardless of the co(2 ...201019880228
down-regulation of defense genes and resource allocation into infected roots as factors for compatibility between fagus sylvatica and phytophthora citricola.phytophthora citricola is a wide spread and highly aggressive pathogen of fagus sylvatica. the hemibiotrophic oomycete infects the roots and establishes a compatible interaction with f. sylvatica. to investigate the transcriptional changes associated with p. citricola infection, 68 custom oligo-microarray measurements were conducted. hierarchical as well as non-hierarchical clustering was carried out to analyze the expression profiles. experimental setup includes a time scale covering the biotro ...201019813036
comparative proteomic analysis of responses to pathogen infection and wounding in fagus sylvatica.defense responses of fagus sylvatica seedlings elicited by infection with the root pathogen phytophthora citricola and root or leaf wounding were compared at local and systemic levels in differential display experiments using two-dimensional gel electrophoresis followed by homology-driven mass spectrometric identification of proteins. a total of 68 protein spots were identified representing 51 protein functions related to protein synthesis and processing, energy, primary and secondary metabolism ...200919575529
identification and characterization of differentially expressed genes from fagus sylvatica roots after infection with phytophthora citricola.phytophthora species are major plant pathogens infecting herbaceous and woody plants including european beech, the dominant or co-dominant tree in temperate europe and an economically important species. for the analysis of the interaction of phytophthora citricola with fagus sylvatica suppression subtractive hybridization was used to isolate transcripts induced during infection and 1,149 sequences were generated. hybridizations with driver and tester populations demonstrated differential express ...200919290528
quantification of mrnas and housekeeping gene selection for quantitative real-time rt-pcr normalization in european beech (fagus sylvatica l.) during abiotic and biotic stress.analyses of different plant stressors are often based on gene expression studies. quantitative real-time rt-pcr (qrt-pcr) is the most sensitive method for the detection of low abundance transcripts. however, a critical point to note is the selection of housekeeping genes as an internal control. many so-called 'housekeeping genes' are often affected by different stress factors and may not be suitable for use as an internal reference. we tested six housekeeping genes of european beech by qrt-pcr u ...200818811005
in vitro antagonism of an actinobacterial kitasatospora isolate against the plant pathogen phytophthora citricola as elucidated with ultrahigh resolution mass spectrometry.many soil microorganisms antagonistic to soil borne plant pathogens are well known for their ability to control diseases in situ. a variety of substances, like lytic enzymes, siderophores and antibiotics, produced by these organisms have the potential to protect roots against pathogens. understanding the ecology and a functional assessment of antagonistic microbial communities in soil requires in-depth knowledge of the mechanisms involved in these interactions, a challenging task in complex syst ...200818588924
involvement of phytophthora species in the decline of beech fagus sylvatica in wallonia (belgium).during the last decade, typical symptoms of phytophthora diseases were observed in beech stands of several european countries. the main symptoms were the presence of bleeding cankers on the stem, a low crown density as well as the yellowing of foliage and the small size of leaves. several species of phytophthora, such as phytophthora citricola, p. cambivora and p. cactorum, were reported as the causal agents. in order to evaluate the implication of the different phytophthora species in beech dec ...200718396824
toward improvements of oomycete transformation protocols.some of the most important plant pathogens worldwide are oomycetes, and billions of dollars are expended annually to suppress diseases they cause. more efficient disease suppression technologies will be derived from a better understanding of the basic biology of these organisms, but inefficient transformation currently limits basic molecular investigations. of the various approaches, transformation of protoplasts using polyethylene glycol/calcium chloride remains most successful, but the frequen ...200818318863
mycorrhizosphere responsiveness to atmospheric ozone and inoculation with phytophthora citricola in a phytotron experiment with spruce/beech mixed cultures.the aim was to analyze functional changes in the mycorrhizosphere (mr) of juvenile spruce and beech grown in a mixture under ambient and twice ambient ozone and inoculated with the root pathogen phytophthora citricola. the phytotron experiment was performed over two vegetation periods, adding the pathogen at the end of the first growing season. root biomass data suggest that the combined treatment affected spruce more than beech and that the negative influence of ozone on stress tolerance agains ...200516388476
single-strand-conformation polymorphism of ribosomal dna for rapid species differentiation in genus phytophthora.single-strand-conformation polymorphism (sscp) of ribosomal dna of 29 species (282 isolates) of phytophthora was characterized in this study. phytophthora boehmeriae, phytophthora botryosa, phytophthora cactorum, phytophthora cambivora, phytophthora capsici, phytophthora cinnamomi, phytophthora colocasiae, phytophthora fragariae, phytophthora heveae, phytophthora hibernalis, phytophthora ilicis, phytophthora infestans, phytophthora katsurae, phytophthora lateralis, phytophthora meadii, phytophth ...200312892637
synthesis and antifungal activity of new n-isoxazolyl-2-iodobenzamides.n-isoxazolyl-2-iodobenzamides 3 and 9, with a benodanil-like structure, were synthesized by refluxing in acetic acid the corresponding benzotriazinones 2 and 8 with potassium iodide for 1 h with the aim to ascertain if they were active as fungicides against phytophthora citricola saw., botrytis cinerea pers., rhizoctonia sp. and alternaria sp. among the tested iodo derivatives, compounds 3b and 9a possess interesting activities against the aforesaid fungal strains in several cases similar to tha ...199910321034
re-evaluation of phytophthora citricola isolates from multiple woody hosts in europe and north america reveals a new species, phytophthora plurivora sp. nov.during large-scale surveys for soilborne phytophthora species in forests and semi-natural stands and nurseries in europe during the last decade, homothallic phytophthora isolates with paragynous antheridia, semipapillate persistent sporangia and a growth optimum around 25 degrees c which did not form catenulate hyphal swellings, were recovered from 39 host species in 16 families. based on their morphological and physiological characters and the similarity of their its dna sequences with p. citri ...200920198142
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