title: Modulation of Ergot Alkaloids in a Grass-Endophyte Symbiosis by Alteration of mRNA Concentrations of an Ergot Alkaloid Synthesis Gene.
abstract: The profile of ergot alkaloids in perennial ryegrass (Lolium perenne) containing the endophytic fungus Epichloë typhina × festucae includes high concentrations of the early pathway metabolites ergotryptamine and chanoclavine-I in addition to the pathway end-product ergovaline. Because these alkaloids differ in activity, we investigated strategies to alter their relative concentrations. An RNAi-based approach reduced the concentration of mRNA from the gene easA, which encodes an enzyme required for a ring closure that separates ergotryptamine and chanoclavine-I from ergovaline. Lower easA mRNA concentrations correlated with lower concentrations of ergovaline and higher concentrations of ergotryptamine and chanoclavine-I. Overexpression of easA led to higher concentrations of ergovaline in leaf blades but not in pseudostems; concentrations of the early pathway metabolites were not altered in overexpression strains. The data indicate that altering the concentration of mRNA from a single gene can change alkaloid flux, but the magnitude of the change was limited and variable.
authors.affiliation: Genetics and Developmental Biology Program, Division of Plant and Soil Sciences, West Virginia University , Morgantown, West Virginia 26506-6108, United States.
authors.forename: Prashanthi
authors.initials: P
authors.lastname: Mulinti
authors.affiliation: Department of Plant Pathology, University of Kentucky , Lexington, Kentucky 40546-0312, United States.
authors.forename: Simona
authors.initials: S
authors.lastname: Florea
authors.affiliation: Department of Plant Pathology, University of Kentucky , Lexington, Kentucky 40546-0312, United States.
authors.forename: Christopher L
authors.initials: CL
authors.lastname: Schardl
authors.affiliation: Genetics and Developmental Biology Program, Division of Plant and Soil Sciences, West Virginia University , Morgantown, West Virginia 26506-6108, United States.
authors.forename: Daniel G
authors.initials: DG
authors.lastname: Panaccione
mesh_terms: D053898:Biosynthetic Pathways; D060026:Endophytes / Q000502:physiology*; D055329:Epichloe / Q000737:chemistry / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D004876:Ergot Alkaloids / Q000096:biosynthesis*; D008129:Lolium / Q000737:chemistry / Q000378:metabolism* / Q000382:microbiology*; D018515:Plant Leaves / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism; D006109:Poaceae / Q000737:chemistry / Q000378:metabolism* / Q000382:microbiology*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D064210:Secondary Metabolism; D013559:Symbiosis
chemical_list: D004876:Ergot Alkaloids; D010940:Plant Proteins; D012333:RNA, Messenger
keywords: Epichloë; Lolium perenne; RNAi; ergovaline; secondary metabolism