Novel, Pseudomonas-derived Antifungal Lipopeptides From A Disease Suppressive Soil In Greenlandic Potato Fields

Rosanna Catherine Hennessy, Charlotte F. Michelsen, Mikkel A. Glaring, Christopher Phippen, Kristian Fog Nielsen, Stefan Olsson, Peter Stougaard

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    Abstract

    Potato cultivation in southwest Greenland omits the use of pesticides, relies on limited crop rotations, and despite the presence of plant pathogenic fungi in the soil, has not suffered from severe disease outbreaks. In this presentation, the bacterial strain Pseudomonas sp. In5 which significantly contributes to the suppressiveness of soil at Inneruulalik in southern Greenland will be explored. A combination of molecular genetics and genomics coupled with matrix-assisted laser desorption ionization – time of flight (MALDI-TOF) imaging mass spectrometry (IMS) identified a large genomic island encoding the two non-ribosomal peptides nunapeptin and nunamycin, which are key components of the antifungal activity of In5. Bacterial-fungal interaction studies uncovered a complex interaction whereby nunamycin appears most active against Rhizoctonia solani with no antimicrobial effect against the oomycete Pythium aphanidermatum. In constrast, nunapeptin is most potent against Pythium aphanidermatum in addition to Fusarium sp. To investigate the genetic regulation of both peptides, we have examined the diversity of LuxR-type regulators across the genomic island including upstream and downstream regions flanking the peptide biosynthetic genes. Functional analysis by knockout and complementation studies together with liquid chromatography – high resolution mass spectrometry (LC-HRMS) showed loss and gain of both antifungal activity and peptide synthesis. Current studies are aimed at unravelling further the complex regulation and mode of action of both peptides in order to develop effective microbial biocontrol agents (mBCAs).
    Original languageEnglish
    Title of host publicationThe Danish Microbiological Society Annual Congress 2015 : Programme & Abstracts
    Place of PublicationCopenhagen
    Publication date2015
    Pages19-19
    Publication statusPublished - 2015
    EventThe Danish Microbiological Society Annual Congress 2015 - Eigtved's Pakhus, Copenhagen, Denmark
    Duration: 9 Nov 20159 Nov 2015

    Conference

    ConferenceThe Danish Microbiological Society Annual Congress 2015
    LocationEigtved's Pakhus
    CountryDenmark
    CityCopenhagen
    Period09/11/201509/11/2015

    Cite this

    Hennessy, R. C., Michelsen, C. F., Glaring, M. A., Phippen, C., Nielsen, K. F., Olsson, S., & Stougaard, P. (2015). Novel, Pseudomonas-derived Antifungal Lipopeptides From A Disease Suppressive Soil In Greenlandic Potato Fields. In The Danish Microbiological Society Annual Congress 2015: Programme & Abstracts (pp. 19-19).