Novel Pseudomonas – derived antifungal lipopeptides from a disease suppressive soil in Greenlandic potato fields

TY - ABST

T1 - Novel Pseudomonas – derived antifungal lipopeptides from a disease suppressive soil in Greenlandic potato fields

AU - Hennessy, Rosanna Catherine

AU - Michelsen, Charlotte Frydenlund

AU - Glaring, Mikkel Andreas

AU - Phippen, Christopher

AU - Nielsen, Kristian F.

AU - Olsson, Stefan

AU - Stougaard, Peter

PY - 2015

Y1 - 2015

N2 - Potato cultivation in southwest Greenland at Inneruulalik 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 previous work, the soil at Inneruulalik was found to be disease suppressive and a source of diverse bacteria with antifungal activity. Using culture-based approaches, the strain Pseudomonas sp. In5 was identified from the soil microbiome shown to have potent antifungal activity. 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 P. 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 using transcriptomics are aimed at unravelling further the complex regulation and mode of action of both peptides in order to develop effective microbial biocontrol agents (mBCAs).

AB - Potato cultivation in southwest Greenland at Inneruulalik 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 previous work, the soil at Inneruulalik was found to be disease suppressive and a source of diverse bacteria with antifungal activity. Using culture-based approaches, the strain Pseudomonas sp. In5 was identified from the soil microbiome shown to have potent antifungal activity. 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 P. 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 using transcriptomics are aimed at unravelling further the complex regulation and mode of action of both peptides in order to develop effective microbial biocontrol agents (mBCAs).

M3 - Conference abstract for conference

T2 - The Danish Microbiological Society Annual Congress 2015

Y2 - 9 November 2015

ER -