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Cerato-platanin from C. fimbriata f. sp. platani is an host resistance inducing protein and is produced by other strains of C. fimbriata and by some other species of the genus Ceratocystis
No full textCerato-platanin (CP) is a 120 amino acids protein [1, 5], produced by the Ascomycete Ceratocystis fimbriata f. sp. platani (Cfp), the causal agent of the plane canker stain. The species C. fimbriata attacks various other plants of considerable importance in agriculture, forestry and for their ornamental value; as a rule, one fungal strain isolated from one host is not virulent on the other plant species, and conversely, susceptible hosts are resistant to C. fimbriata strains if they come from hosts other than themselves. This means that the forma specialis platani of the species C. fimbriata attacks only the trees belonging to the genus Platanus, but not the hosts of the all other formae speciales of the fungus. CP is located in the cell walls of Cfp ascospores, hyphae and conidia, and is early secreted when Cfp is grown in liquid culture [2, 3]. CP elicits phytoalexin synthesis and/or cell necrosis in host and in non-host tissues; in plane leaves the main effects of CP are to cause a great increase in primary starch and a certain degree of intercellular and intracellular disorganization of the spongy parenchyma cells and plasmolysis processes; in addition, an increase of intracellular phenolic compounds has been observed in the palisade cells [3, 4]. In the present work we report that the minimum CP concentration able to induce the decrease of the 50% Cfp growth on plane leaves is of about 5 x 10-5 M; the maximum inducing effect has been obtained 24-48 hours post treatment. At this time, numerous defense-related genes are over-expressed, as it has been shown by Suppressive Subtractive Hybridisation. Moreover, results so far obtained by immunotechnical experiments on a total of 17 strains (9 of C. fimbriata, as well as 1 isolate each of C. moniliforme, C. allantospora, C. fagacearum, C. laricicola, C. ambrosia, Microascus cirrosus, Ophiostoma ulmi and O. novo-ulmi) indicate that a CP-homologous protein occurs in all strains of C. fimbriata and in some other species of Ceratocystis. For some strains of C. fimbriata the coding sequences of the cp-hortologous genes have been obtained, and then the sequences of the deduced proteins. BIBLIOGRAFIA 1. Pazzagli L, Cappugi G, Manao G, Camici G, Santini A and Scala A, 1999. Purification of cerato-platanin, a new phytotoxic protein from Ceratocystis fimbriata f.sp. platani. Journal of Biological Chemistry 274: 24959-24964. 2. Boddi S, Comparini C, Calamassi R, Pazzagli L, Cappugi G and Scala A, 2004. Cerato-platanin protein is located in the cell walls of ascospores, conidia and hyphae of Ceratocystis fimbriata f. sp. platani. FEMS Microbiology Letters 233: 341-346. 3. Scala A, Pazzagli L, Comparini C, Santini A, Tegli S and Cappugi G, 2004. Cerato-platanin, an early-produced protein by Ceratocystis fimbriata f. sp. platani, elicits phytoalexin synthesis in host and non-host plants. Journal of Plant Pathology 86: 23-29. 4. Bennici A, Calamassi R, Pazzagli L, Comparini C, Schiff S, Bovelli R, Mori B, Tani C and Scala A, 2005. Cytological and ultrastructural responses of Platanus acerifolia (Ait.) Willd. leaves to cerato-platanin, a protein from Ceratocystis fimbriata f. sp. platani. Phytopathologia Mediterranea 44: 153-161. 5. Pazzagli L, Pantera B, Carresi L, Zoppi C, Pertinhez TA, Spisni A, Tegli S, Scala A, Cappugi G, 2006. Cerato-platanin, the first member of a new fungal protein family: cloning, expression and characterization. Cell Biochemistry and Biophysics 44: 512-521
The NMR-derived Structure of Cerato-Ulmin, a Phytotoxic Hydrophobin, in the Monomeric Form
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Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Cerato-platanin and cerato-populin induce differential resistance responses in plane leaves
No full textCerato-platanin (CP) and cerato-populin (Pop1) are small proteins produced by the phytopathogenic fungi Ceratocystis platani and C. populicola, respectively. CP and Pop1 behaved as PAMPs, since they elicited typical defense responses in various host and non-host plants. CP and Pop1 are well-structured α/β proteins with a identity of about 63% and the conservative substitution of approximately 12% of amino acids. Also the analysis by circular dichroism showed differences in the secondary structure between the two proteins. The present work aimed to understand whether these structural differences are reflected in differences in their eliciting activity. For this purpose we have used the plane leaves because this is the model on which we work long and know really. In addition to assess the inhibition of fungal growth on plane leaves, we studied the following parameters at 3, 6, 9, 12, 24, 48 hours post treatment: (1) determination and visualization of hydrogen peroxide and nitric oxide by using the specific probe 2’-7’-dichlorodihydrofluorescein diacetate and the fluorescent dye 4,5 diaminofluorescein diacetate, respectively; (2) the viability of cells determined by staining with propidium iodide and the in situ detection of DNA fragmentation (TUNEL assay); (3) the expression of the genes PR5 (thaumatin), LTP (Lipid transfer protein) e APX (Ascorbato perossidasi). All results show marked differences in the eliciting capacity of the two proteins; in particular the plane resistance responses are activated earlier by CP than by Pop1. These results are the basis for identifying the protein region(s) involved in the PAMP activity
1H, 15N and 13C Resonance Assignments of Cerato-platanin, a Phytotoxic Protein from Ceratocystis fimbriata
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Modulation of Gene Expression Induced in Platanus Acerifolia by Cerato-Platanin and Conidial Suspension of Ceratocystis Platani
No full textCerato-platanin (CP) is a small protein produced by Ascomycete Ceratocystis platani, the causal agent of plane canker stain. Cep is pathogenic to Platanus orientalis, P. occidentalis and their hybrid P. acerifolia. CP is located in the fungal cell walls, is early released in culture, and elicits defence-related structural and physiological responses in host and non-host plants, such as cell plasmolysis and death, phenolic compounds and phytoalexin accumulation (Pazzagli et al., J. Biol. Chem. 274: 24959-24964, 1999; Boddi et al., FEMS Microbiol. Letters 233: 341-346, 2004; Scala et al., J. Plant Pathol. 86: 23-29,2004; Bennici et al., Caryologia 59: 291-298, 2006). Recently, it has been demonstrated the close correlation between the CP treatment of plane leaves and the subsequent growth inhibition of C. platani on the surface of the treated leaves together with the production of phytoalexins and the over-transcription of regulatory and defense-associated genes (Fontana et al., J. Plant Pathol. 90: 293-304, 2008).
The aim of the present study was to provide further information on the modulation of gene expression that occurs in the plane tree by CP treatment in order to improve our understanding of the potential of CP to function as a PAMP (Pathogen-Associated Molecular Pattern) protein in the pathogenic process of the C. platani-P. acerifolia interaction.
In the present study we have isolated others clones from a cDNA library constructed using suppression subtractive hybridization (SSH) technique (Fontana et al., J. Plant Pathol. 90: 293-304, 2008) and the putative differentially expressed genes were identified using the FASTA, BLASTN and BLASTX programs. The up-regulated clones were classified in the macro putative groups taking in account the functional categories established for Arabidopsis (The Arabidopsis Genome Initiative, Nature 408: 796-815, 2000). We have analysed, moreover, some of them by relative PCR using total RNA extracted from leaves treated with CP or fungal conidia at 6, 24 and 48 hours after treatments in order to investigate possible differences in gene expression during CP/plant and fungus/plant interactions
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