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Hongye Li - One of the best experts on this subject based on the ideXlab platform.

  • glucosylceramides are required for mycelial growth and full virulence in Penicillium digitatum
    Biochemical and Biophysical Research Communications, 2014
    Co-Authors: Mingshuang Wang, Ruoxin Ruan, Weili Wang, Hongye Li
    Abstract:

    Abstract Glucosylceramides (GlcCers) are important lipid components of the membrane systems of eukaryotes. Recent studies have suggested the roles for GlcCers in regulating fungal growth and pathogenesis. In this study, we report the identification and functional characterization of PdGcs1, a gene encoding GlcCer synthase (GCS) essential for the biosynthesis of GlcCers, in Penicillium digitatum genome. We demonstrated that the deletion of PdGcs1 in P. digitatum resulted in the complete loss of production of GlcCer (d18:1/18:0 h) and GlcCer (d18:2/18:0 h), a decrease in vegetation growth and sporulation, and a delay in spore germination. The virulence of the PdGcs1 deletion mutant on citrus fruits was also impaired, as evidenced by the delayed occurrence of water soaking lesion and the formation of smaller size of lesion. These results suggest that PdGcs1 is a bona fide GCS that plays an important role in regulating cell growth, differentiation, and virulence of P. digitatum by controlling the biosynthesis of GlcCers.

  • Improvement of a gene targeting system for genetic manipulation in Penicillium digitatum
    Journal of Zhejiang University-science B, 2014
    Co-Authors: Qian Xu, Ming-shang Wang, Hongye Li
    Abstract:

    Penicillium digitatum is the most important pathogen of postharvest citrus. Gene targeting can be done in P. digitatum using homologous recombination via Agrobacterium tumefaciens mediated transformation (ATMT), but the frequencies are often very low. In the present study, we replaced the Ku80 homolog (a gene of the non-homologous end-joining (NHEJ) pathway) with the hygromycin resistance cassette (hph) by ATMT. No significant change in vegetative growth, conidiation, or pathogenicity was observed in Ku80-deficient strain (ΔPdKu80) of P. digitatum. However, using ΔPdKu80 as a targeting strain, the gene-targeting frequencies for both genes PdbrlA and PdmpkA were significantly increased. These results suggest that Ku80 plays an important role in homologous integration and the created ΔPdKu80 strain would be a good candidate for rapid gene function analysis in P. digitatum.

  • pdmle1 a specific and active transposon acts as a promoter and confers Penicillium digitatum with dmi resistance
    Environmental Microbiology Reports, 2013
    Co-Authors: Qian Xu, Tianyuan Zhang, Ruoxin Ruan, Hongye Li
    Abstract:

    Summary Previously, we found a 199 bp element which inserted into the promoter of PdCYP51B gene in Penicillium digitatum, was associated with the overexpression of this gene and DMI fungicides resistance. However, the mechanism how this 199 bp element upregulate the expression of downstream gene was completely unknown. In the current study, we confirmed that this 199 bp element was a MITE-like element, designated as PdMLE1. blast searching and Southern blot showed that this 199 bp element was unique to P. digitatum. Genome-wide localization of PdMLE1 showed that it preferentially inserted into A + T rich regions, and several copies localized at the coding or regulation regions of genes were found. Penicillium digitatum mutant harbouring the PdMLE1 fused GFP gene showed the strong green fluorescence, indicating the powerful promoter activity of PdMLE1. By promoter deletion method, we identified a 20 bp core sequence in PdMLE1 which was associated with its promoter activity. In addition, we also limited the core element of PdCYP51B promoter to a 368 bp region. Collectively, we proposed a model that PdMLE1 acted as a powerful promoter and most likely recruited the transcription factor(s), therefore led to the overexpression of PdCYP51B gene and conferred P. digitatum with DMI resistance. This is the first regulation model of transposon resulted fungicide resistance proved in plant pathogens.

  • PdMfs1, a major facilitator superfamily transporter from Penicillium digitatum, is partially involved in the imazalil-resistance and pathogenicity
    African Journal of Microbiology Research, 2012
    Co-Authors: Ji-ye Wang, Tianyuan Zhang, Zhonghua Ma, Hongye Li
    Abstract:

    Penicillium digitatum, causing green mold, is the most important postharvest pathogen of citrus fruits worldwide. Fungicide imazalil has been used in control of this mold for more than three decades. In the presence of imazalil pressure, imazalil resistance strain has risen worldwide. To explore the potential role of multidrug resistance (MDR) in imazalil resistance, a membrane efflux transporter Penicillium digitatum major facilitator surperfamily1 (PdMfs1) was cloned, and its functions in imazalil resistance and pathogenicity were analyzed. PdMfs1 has an open reading frame (ORF) of 1,876 bp and 3 introns of 55, 49 and 71 bp, respectively. It encodes a protein of 566 amino acids that shares a high degree of similarity with members of the drug: H+ antiporter efflux family of the major facilitator surperfamily (MFS) transporters of other fungi. Expression of PdMfs1was up-regulated by treatment with imazalil and other fungicdes in both imazalil-sensitive and –resistant P. digitatum. Disruption of PdMfs1 gene rendered P. digitatum more sensitive to imazalil and other DMI fungicides, and the imazalil-resistance could be rescued by reintroducing the wild-type PdMfs1 gene into the PdMfs1 disruption mutant (ΔPdMfs1).Overexpression of PdMfs1 rendered P. digitatum more resistant to imazalil. These results indicate that PdMfs1 is a multidrug transporter of P. digitatum that could pump imazalil out of cells, thus contributing resistance to imazalil partially. Pathogenicity analysis showed that the disease on the citrus fruits inoculated with the ΔPdMfs1 developed much slower than that induced by the parental strain PdW03, suggesting that PdMfs1 also plays a role on the virulence of P. digitatum.   Key words: Penicillium digitatum, major facilitator surperfamily (MFS) transporters,imazalil resistance, virulence.

  • complete mitochondrial genome sequence of the phytopathogenic fungus Penicillium digitatum and comparative analysis of closely related species
    Fems Microbiology Letters, 2011
    Co-Authors: Hongye Li, Dongliang Yu
    Abstract:

    The complete mitochondrial genome of Penicillium digitatum (Pers.:Fr) Sacc is reported, the first time in a phytopathogenic Penicillium species. Comparative analysis revealed its close relationship to mitochondrial genomes of other Penicillium and Aspergillus species, both in gene content and in arrangement. The intron content of protein coding genes revealed several differences. The different exon–intron organization of CytochromeOxidaseSubunit 1 genes indicated their common origin before the divergence of Penicillium and Aspergillus, and that, largely, their introns were transmitted vertically.

Gabriella Cirvilleri - One of the best experts on this subject based on the ideXlab platform.

  • efficacy of killer yeasts in the biological control of Penicillium digitatum on tarocco orange fruits citrus sinensis
    Food Microbiology, 2012
    Co-Authors: C Platania, Cristina Restuccia, Serena Muccilli, Gabriella Cirvilleri
    Abstract:

    Killer Saccharomyces cerevisiae and Wickerhamomyces anomalus yeast strains were tested as biocontrol agents against Penicillium digitatum, one the most important causes of postharvest decay in orange fruits. W. anomalus, grown on acidified medium, demonstrated micocinogenic activity against P. digitatum ,a s indicated by large inhibition halos and hyphal damage resulting from b-glucanase activity. Oranges that had been deliberately inoculated with pathogens were protected from decay by W. anomalus. Inoculation of oranges with W. anomalus strains BS 91 and BS 92 reduced disease severity to 1 and 4%, respectively, for up to 10 days in storage.

  • Efficacy of killer yeasts in the biological control of Penicillium digitatum on Tarocco orange fruits (Citrus sinensis)
    Food Microbiology, 2012
    Co-Authors: C Platania, Cristina Restuccia, Serena Muccilli, Gabriella Cirvilleri
    Abstract:

    Killer Saccharomyces cerevisiae and Wickerhamomyces anomalus yeast strains were tested as biocontrol agents against Penicillium digitatum, one the most important causes of postharvest decay in orange fruits.W.anomalus, grown on acidified medium, demonstrated micocinogenic activity against P.digitatum, as indicated by large inhibition halos and hyphal damage resulting from β-glucanase activity.Oranges that had been deliberately inoculated with pathogens were protected from decay by W. anomalus. Inoculation of oranges with W.anomalus strains BS 91 and BS 92 reduced disease severity to 1 and 4%, respectively, for up to 10 days in storage. © 2011 Elsevier Ltd.

Samir Droby - One of the best experts on this subject based on the ideXlab platform.

  • de novo assembly and characterization of the transcriptome of metschnikowia fructicola reveals differences in gene expression following interaction with Penicillium digitatum and grapefruit peel
    BMC Genomics, 2013
    Co-Authors: Vera Hershkovitz, Michael Wisniewski, Noa Sela, Leena Tahasalaime, Ginat Rafael, Clarita Kessler, Maggie Levy, Samir Droby
    Abstract:

    Background The yeast Metschnikowia fructicola is an antagonist with biological control activity against postharvest diseases of several fruits. We performed a transcriptome analysis, using RNA-Seq technology, to examine the response of M. fructicola with citrus fruit and with the postharvest pathogen, Penicillium digitatum.

  • Penicillium digitatum suppresses production of hydrogen peroxide in host tissue during infection of citrus fruit
    Phytopathology, 2007
    Co-Authors: Dumitru Macarisin, Michael Wisniewski, L Cohen, A Eick, G Rafael, E Belausov, Samir Droby
    Abstract:

    Macarisin, D., Cohen, L., Eick, A., Rafael, G., Belausov, E., Wisniewski, M., and Droby, S. 2007. Penicillium digitatum suppresses production of hydrogen peroxide in host tissue during infection of citrus fruit. Phytopathology 97:1491-1500. During the infection of citrus fruit by Penicillium digitatum there is little evidence of a host defense response. This suggests that P. digitatum has the ability to suppress host defenses. The current study demonstrates that P. digitatum suppresses a defense-related hydrogen peroxide (H2O2) burst in host tissue. In contrast, the nonhost pathogen, Penicillium expansum, triggers production of a significant amount of H2O2 in citrus fruit exocarp. Using laser scanning confocal microscopy, we demonstrated that P. digitatum suppressed an elevation in H2O2 up to 42 h after inoculation. Nevertheless, H2O2 levels around wounds inoculated with P. expansum increased by 63-fold above the control. P. digitatum continued to suppress H2O2 production in citrus fruit exocarp up to 66 h postinoculation and H2O2 levels were actually threefold below that of noninoculated controls. In contrast, the H2O2 level was still about 11-fold above the control value in wound sites inoculated with P. expansum. Studies on the effect of organic acids (as pH modulators) on the response of citrus fruit to compatible and noncompatible pathogens indicated that pathogenicity was enhanced only when host-tissue acidification was accompanied by the suppression of H2O2. Additionally, pathogenicity of both P. digitatum and P. expansum on citrus fruit was significantly enhanced by the H2O2-scavenging enzyme catalase. Based on our study and previous reports regarding the potential involvement of citric acid and catalase in green mold pathogenesis, we suggest that these compounds are strongly associated with the virulence of P. digitatum.

  • influence of cacl2 on Penicillium digitatum grapefruit peel tissue and biocontrol activity of pichia guilliermondii
    Phytopathology, 1997
    Co-Authors: Samir Droby, Michael Wisniewski, L Cohen, B Weiss, D Touitou, Y Eilam, Edo Chalutz
    Abstract:

    ABSTRACT Interactions between CaCl2, grapefruit peel tissue, Penicillium digitatum, and the yeast antagonist Pichia guilliermondii strain US-7 were investigated. Application of 68 or 136 mM CaCl2 to grapefruit surface wounds reduced the incidence of green mold caused by Penicillium digitatum by 43 to 52%. In laboratory tests, a cell suspension (107 cells/ml) of Pichia guilliermondii containing either 68 or 136 mM CaCl2 reduced the incidence of green mold from 27 to 3%. In large scale tests, dip application of 136 mM CaCl2 with US-7 (107 cells/ml) significantly decreased the number of wounds infected by Penicillium digitatum. CaCl2, with or without yeast cells, stimulated ethylene production in grapefruit tissue. Increasing concentrations of CaCl2 resulted in decreased spore germination and germ tube elongation of Penicillium digitatum. Pectinolytic activity of crude enzyme preparations of Penicillium digitatum was also inhibited by the presence of increasing concentrations of CaCl2. US-7 exhibited a stron...

C Platania - One of the best experts on this subject based on the ideXlab platform.

  • efficacy of killer yeasts in the biological control of Penicillium digitatum on tarocco orange fruits citrus sinensis
    Food Microbiology, 2012
    Co-Authors: C Platania, Cristina Restuccia, Serena Muccilli, Gabriella Cirvilleri
    Abstract:

    Killer Saccharomyces cerevisiae and Wickerhamomyces anomalus yeast strains were tested as biocontrol agents against Penicillium digitatum, one the most important causes of postharvest decay in orange fruits. W. anomalus, grown on acidified medium, demonstrated micocinogenic activity against P. digitatum ,a s indicated by large inhibition halos and hyphal damage resulting from b-glucanase activity. Oranges that had been deliberately inoculated with pathogens were protected from decay by W. anomalus. Inoculation of oranges with W. anomalus strains BS 91 and BS 92 reduced disease severity to 1 and 4%, respectively, for up to 10 days in storage.

  • Efficacy of killer yeasts in the biological control of Penicillium digitatum on Tarocco orange fruits (Citrus sinensis)
    Food Microbiology, 2012
    Co-Authors: C Platania, Cristina Restuccia, Serena Muccilli, Gabriella Cirvilleri
    Abstract:

    Killer Saccharomyces cerevisiae and Wickerhamomyces anomalus yeast strains were tested as biocontrol agents against Penicillium digitatum, one the most important causes of postharvest decay in orange fruits.W.anomalus, grown on acidified medium, demonstrated micocinogenic activity against P.digitatum, as indicated by large inhibition halos and hyphal damage resulting from β-glucanase activity.Oranges that had been deliberately inoculated with pathogens were protected from decay by W. anomalus. Inoculation of oranges with W.anomalus strains BS 91 and BS 92 reduced disease severity to 1 and 4%, respectively, for up to 10 days in storage. © 2011 Elsevier Ltd.

Michael Wisniewski - One of the best experts on this subject based on the ideXlab platform.

  • de novo assembly and characterization of the transcriptome of metschnikowia fructicola reveals differences in gene expression following interaction with Penicillium digitatum and grapefruit peel
    BMC Genomics, 2013
    Co-Authors: Vera Hershkovitz, Michael Wisniewski, Noa Sela, Leena Tahasalaime, Ginat Rafael, Clarita Kessler, Maggie Levy, Samir Droby
    Abstract:

    Background The yeast Metschnikowia fructicola is an antagonist with biological control activity against postharvest diseases of several fruits. We performed a transcriptome analysis, using RNA-Seq technology, to examine the response of M. fructicola with citrus fruit and with the postharvest pathogen, Penicillium digitatum.

  • Penicillium digitatum suppresses production of hydrogen peroxide in host tissue during infection of citrus fruit
    Phytopathology, 2007
    Co-Authors: Dumitru Macarisin, Michael Wisniewski, L Cohen, A Eick, G Rafael, E Belausov, Samir Droby
    Abstract:

    Macarisin, D., Cohen, L., Eick, A., Rafael, G., Belausov, E., Wisniewski, M., and Droby, S. 2007. Penicillium digitatum suppresses production of hydrogen peroxide in host tissue during infection of citrus fruit. Phytopathology 97:1491-1500. During the infection of citrus fruit by Penicillium digitatum there is little evidence of a host defense response. This suggests that P. digitatum has the ability to suppress host defenses. The current study demonstrates that P. digitatum suppresses a defense-related hydrogen peroxide (H2O2) burst in host tissue. In contrast, the nonhost pathogen, Penicillium expansum, triggers production of a significant amount of H2O2 in citrus fruit exocarp. Using laser scanning confocal microscopy, we demonstrated that P. digitatum suppressed an elevation in H2O2 up to 42 h after inoculation. Nevertheless, H2O2 levels around wounds inoculated with P. expansum increased by 63-fold above the control. P. digitatum continued to suppress H2O2 production in citrus fruit exocarp up to 66 h postinoculation and H2O2 levels were actually threefold below that of noninoculated controls. In contrast, the H2O2 level was still about 11-fold above the control value in wound sites inoculated with P. expansum. Studies on the effect of organic acids (as pH modulators) on the response of citrus fruit to compatible and noncompatible pathogens indicated that pathogenicity was enhanced only when host-tissue acidification was accompanied by the suppression of H2O2. Additionally, pathogenicity of both P. digitatum and P. expansum on citrus fruit was significantly enhanced by the H2O2-scavenging enzyme catalase. Based on our study and previous reports regarding the potential involvement of citric acid and catalase in green mold pathogenesis, we suggest that these compounds are strongly associated with the virulence of P. digitatum.

  • influence of cacl2 on Penicillium digitatum grapefruit peel tissue and biocontrol activity of pichia guilliermondii
    Phytopathology, 1997
    Co-Authors: Samir Droby, Michael Wisniewski, L Cohen, B Weiss, D Touitou, Y Eilam, Edo Chalutz
    Abstract:

    ABSTRACT Interactions between CaCl2, grapefruit peel tissue, Penicillium digitatum, and the yeast antagonist Pichia guilliermondii strain US-7 were investigated. Application of 68 or 136 mM CaCl2 to grapefruit surface wounds reduced the incidence of green mold caused by Penicillium digitatum by 43 to 52%. In laboratory tests, a cell suspension (107 cells/ml) of Pichia guilliermondii containing either 68 or 136 mM CaCl2 reduced the incidence of green mold from 27 to 3%. In large scale tests, dip application of 136 mM CaCl2 with US-7 (107 cells/ml) significantly decreased the number of wounds infected by Penicillium digitatum. CaCl2, with or without yeast cells, stimulated ethylene production in grapefruit tissue. Increasing concentrations of CaCl2 resulted in decreased spore germination and germ tube elongation of Penicillium digitatum. Pectinolytic activity of crude enzyme preparations of Penicillium digitatum was also inhibited by the presence of increasing concentrations of CaCl2. US-7 exhibited a stron...