Planta Med 2014; 80 - SL7
DOI: 10.1055/s-0034-1394495

Exploring the hidden biosynthetic potential of fungi – Evaluation of epigenetic modifications through metabolomics

PM Allard 1, M Perisic 1, F Mehl 1, J Boccard 1, YS Wong 2, K Gindro 3, JL Wolfender 1
  • 1School of Pharmaceutical Sciences, EPGL, University of Geneva, University of Lausanne, Quai Ernest-Ansermet 30, CH-1211 Geneva 4, Switzerland
  • 2Département de Pharmacochimie Moléculaire, Université Joseph Fourier, Grenoble 1, CNRS UMR 5063, CNRS ICMG FR 2607, bâtiment André Rassat, 470 rue de la Chimie, F-38041 Grenoble Cedex 9, France
  • 3Swiss Federal Research Station Agroscope Changins-Wadenswil, Route de Duillier, P.O. Box 1012, CH-1260 Nyon, Switzerland

The interest of microorganisms as a valuable source of bioactive compounds needs no more justifications. Since the isolation of Flemming's penicillin G from Penicillium notatum to the discovery of the proteasome inhibitor salinosporamide A from Salinospora tropica, numerous valuable biologically active metabolites were isolated. Recent insights from the progress in genetics have shed a new light on the biosynthesis of microbial natural products. It is now well known that under classical culture conditions in the laboratory, microorganisms will only express a small proportion of their biosynthetic potential [1]. This phenomenon, known as gene cluster silencing, is very common and has been reported to occur for a vast range of living organisms [2]. Recently new approaches for studying silent biosynthetic pathways in eukaryotes have appeared [3,4]. In order to explore the hidden biosynthetic potential of filamentous fungi we used small molecule epigenetic modificators (EM) of various classes (HDACi, DNAMTi) on phylogenetically diverse fungal strains. The supplementation of these EM in culture media allowed us to induce the production of various secondary metabolites not detected in control conditions. In order to evidence these inductions and select promising candidates for further scale-up culture, a metabolomics workflow implying UHPLC-HRMS analysis, semi-automated dereplication procedures, MS/MS networks construction and multivariate data analysis was set up. This workflow is presented herein in detail. It allowed us to highlight the production of various secondary metabolites not detected in control conditions. The application of HR-MS/MS networking provided valuable information regarding structures of the induced features. In particular, a family of closely related compounds was induced in one of the treated strain, thus indicating the probable unlocking of a common biosynthetic cluster.

Keywords: Metabolomics, fungi, epigenetics, molecular networks, high-resolution mass spectrometry

References:

[1] Chiang Y-M, Lee K-H et al. Unlocking fungal cryptic natural products. Nat Prod Commun 2009; 4: 1505 – 1510.

[2] Gross H. Genomic mining – a concept for the discovery of new bioactive natural products. Curr Opin Drug Discov Devel 2009; 12: 207 – 219.

[3] Wang X, Sena Filho JG et al. Chemical epigenetics alters the secondary metabolite composition of guttate excreted by an atlantic-forest-soil-derived Penicillium citreonigrum. J Nat Prod 2010; 73: 942 – 948.

[4] Williams RB, Henrikson JC et al. Epigenetic remodeling of the fungal secondary metabolome. Org Biomol Chem 2008; 6: 1895 – 1897.