A polyphasic approach for the characterization of endophytic Alternaria strains isolated from grapevines

Rachele Polizzotto, Birgitte Andersen, Marta Martini, Simone Grisan, Gemma Assante, Rita Musetti

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    A polyphasic approach was set up and applied to characterize 20 fungal endophytes belonging to the genus Alternaria, recovered from grapevine in different Italian regions.Morphological, microscopical, molecular and chemical investigations were performed and the obtained results were combined in a pooled cluster analysis. Following morphological analyses, all strains were grouped according to their three-dimensional sporulation pattern on PCA and to the colony characteristics on different substrates. After DNA extraction, all strains were analyzed by RAPD-PCR and the resulting profiles were subjected to cluster analysis. The metabolites extracted from the 20 Alternaria endophytes were analyzed by a HPLC and the resulting metabolite profiles were subjected to multivariate statistic analyses. In comparison with reference 'small-spored' Alternaria species, the 20 strains were segregated into two morphological groups: one belonging to the A. arborescens species-group and a second to the A. tenuissima species-group. RAPD analysis also showed that grapevine endophytes belonged to either the A. arborescens or the A. tenuissima species-group and that they were molecularly distinct from strains belonging to A. alternata. Chemotaxonomy gave the same grouping: the grapevine endophytic strains belong to A. arborescens or A. tenuissima species-groups producing known metabolites typical of these species-groups. Interestingly, the 20 grapevine endophytes were able to produce also a number of unknown metabolites, whose characterization could be useful for a more precise segregation of the two species-groups.The results show how complementary morphological, molecular and chemical data can clarify relationships among endophyte species-groups of low morphological divergence. (C) 2011 Elsevier B.V. All rights reserved.
    Original languageEnglish
    JournalJournal of Microbiological Methods
    Issue number1
    Pages (from-to)162-171
    Publication statusPublished - 2012


    • Italy Europe Palearctic region
    • chemotaxonomy
    • Dicotyledones Angiospermae Spermatophyta Plantae (Angiosperms, Dicots, Plants, Spermatophytes, Vascular Plants) - Vitaceae [26940] grapevine common host
    • Fungi Plantae (Fungi, Microorganisms, Nonvascular Plants, Plants) - Fungi Imperfecti or Deuteromycetes [15500] Alternaria tenuissima species spore Alternaria arborescens species spore
    • DNA
    • metabolite
    • 10060, Biochemistry studies - General
    • 10062, Biochemistry studies - Nucleic acids, purines and pyrimidines
    • 51522, Plant physiology - Chemical constituents
    • chemical analysis laboratory techniques
    • DNA extraction laboratory techniques
    • HPLC high performance liquid chromatography laboratory techniques, chromatographic techniques
    • microscopy laboratory techniques, imaging and microscopy techniques
    • molecular analysis laboratory techniques
    • morphological analysis laboratory techniques
    • multivariate statistical analysis mathematical and computer techniques
    • pooled cluster analysis mathematical and computer techniques
    • RAPD-PCR laboratory techniques, genetic techniques
    • Biochemistry and Molecular Biophysics
    • Methods and Techniques


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