title: Unravelling the biosynthesis of pyriculol in the rice blast fungus Magnaporthe oryzae.
abstract: Pyriculol was isolated from the rice blast fungus Magnaporthe oryzae and found to induce lesion formation on rice leaves. These findings suggest that it could be involved in virulence. The gene MoPKS19 was identified to encode a polyketide synthase essential for the production of the polyketide pyriculol in the rice blast fungus M. oryzae. The transcript abundance of MoPKS19 correlates with the biosynthesis rate of pyriculol in a time-dependent manner. Furthermore, gene inactivation of MoPKS19 resulted in a mutant unable to produce pyriculol, pyriculariol and their dihydro derivatives. Inactivation of a putative oxidase-encoding gene MoC19OXR1, which was found to be located in the genome close to MoPKS19, resulted in a mutant exclusively producing dihydropyriculol and dihydropyriculariol. By contrast, overexpression of MoC19OXR1 resulted in a mutant strain only producing pyriculol. The MoPKS19 cluster, furthermore, comprises two transcription factors MoC19TRF1 and MoC19TRF2, which were both found individually to act as negative regulators repressing gene expression of MoPKS19. Additionally, extracts of ΔMopks19 and ΔMoC19oxr1 made from axenic cultures failed to induce lesions on rice leaves compared to extracts of the wild-type strain. Consequently, pyriculol and its isomer pyriculariol appear to be the only lesion-inducing secondary metabolites produced by M. oryzae wild-type (MoWT) under these culture conditions. Interestingly, the mutants unable to produce pyriculol and pyriculariol were as pathogenic as MoWT, demonstrating that pyriculol is not required for infection.
authors.affiliation: Institut für Biotechnologie und Wirkstoff-Forschung gGmbH (IBWF), Erwin-Schrödinger Str. 56, D-67663 Kaiserslautern, Germany.
authors.forename: Stefan
authors.initials: S
authors.lastname: Jacob
authors.affiliation: Institut für Biotechnologie und Wirkstoff-Forschung gGmbH (IBWF), Erwin-Schrödinger Str. 56, D-67663 Kaiserslautern, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Grötsch
authors.affiliation: Institut für Biotechnologie und Wirkstoff-Forschung gGmbH (IBWF), Erwin-Schrödinger Str. 56, D-67663 Kaiserslautern, Germany.
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Foster
authors.affiliation: Institut für Biotechnologie und Wirkstoff-Forschung gGmbH (IBWF), Erwin-Schrödinger Str. 56, D-67663 Kaiserslautern, Germany.
authors.forename: Anja
authors.initials: A
authors.lastname: Schüffler
authors.affiliation: Institut für Biotechnologie und Wirkstoff-Forschung gGmbH (IBWF), Erwin-Schrödinger Str. 56, D-67663 Kaiserslautern, Germany.
authors.forename: Patrick H
authors.initials: PH
authors.lastname: Rieger
authors.affiliation: Institute of Organic Chemistry, Johannes Gutenberg University of Mainz, Duesbergweg 10-14, D-55128 Mainz, Germany.
authors.forename: Louis P
authors.initials: LP
authors.lastname: Sandjo
authors.affiliation: Institute of Organic Chemistry, Johannes Gutenberg University of Mainz, Duesbergweg 10-14, D-55128 Mainz, Germany.
authors.forename: Johannes C
authors.initials: JC
authors.lastname: Liermann
authors.affiliation: Institute of Organic Chemistry, Johannes Gutenberg University of Mainz, Duesbergweg 10-14, D-55128 Mainz, Germany.
authors.forename: Till
authors.initials: T
authors.lastname: Opatz
authors.affiliation: Institut für Mikrobiologie und Weinforschung, Johannes Gutenberg University of Mainz, Johann-Joachim-Becherweg 15, D-55128 Mainz, Germany.|Institut für Biotechnologie und Wirkstoff-Forschung gGmbH (IBWF), Erwin-Schrödinger Str. 56, D-67663 Kaiserslautern, Germany.
authors.forename: Eckhard
authors.initials: E
authors.lastname: Thines
mesh_terms: D001547:Benzaldehydes / Q000378:metabolism*; D005233:Fatty Alcohols / Q000378:metabolism*; D015966:Gene Expression Regulation, Fungal / Q000235:genetics*; D020082:Magnaporthe / Q000235:genetics / Q000472:pathogenicity*; D005810:Multigene Family / Q000235:genetics; D012275:Oryza / Q000382:microbiology*; D010935:Plant Diseases / Q000382:microbiology; D018515:Plant Leaves / Q000382:microbiology; D048630:Polyketide Synthases / Q000235:genetics*; D061065:Polyketides / Q000378:metabolism*; D064210:Secondary Metabolism / Q000502:physiology; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism
chemical_list: D001547:Benzaldehydes; D005233:Fatty Alcohols; D061065:Polyketides; D014157:Transcription Factors; C000623120:pyriculol; D048630:Polyketide Synthases