DISSERTATIONES SCHOLA DOCTORALIS SCIENTIAE CIRCUMIECTALIS, ALIMENTARIAE, BIOLOGICAE. UNIVERSITATIS HELSINKIENSIS 2/2017 JUHA KONTTURI Type III Polyketide Synthases from Gerbera hybrida DEPARTMENT OF AGRICULTURAL SCIENCES FACULTY OF AGRICULTURE AND FORESTRY DOCTORAL PROGRAMME IN PLANT SCIENCES UNIVERSITY OF HELSINKI Type III Polyketide Synthases from Gerbera Hybrida Juha Kontturi Biotechnology Doctoral school in Plant Sciences Department of Agricultural Sciences Faculty of Agriculture and Forestry University of Helsinki ACADEMIC DISSERTATION To be presented, with the permission of the Faculty of Agriculture and Forestry of the University of Helsinki, for public examination in the lecture room B6 (Metsätieteiden talo, Latokartanonkaari 7) on 10th of February 2017 at 12 o’clock. Supervisor: Professor Teemu Teeri Department of Agricultural Sciences University of Helsinki Follow-up group: Docent Jussi Joensuu VTT Technical Research Centre of Finland Doctor Milla Pietiäinen University of Helsinki Reviewers: Docent/Principal Scientist Anneli Ritala VTT Technical Research Centre Finland Professor Rob Veerporte University of Leiden Opponent: Doctor Günter Brader Austrian Institute of Technology Custos: Professor Teemu Teeri Department of Agricultural Sciences University of Helsinki, Finland ISSN 2342-5423 ISBN 978-951-51-2949-9 (paperback) ISBN 978-951-51-2950-5 (PDF) ethesis.helsinki.fi Kiriprintti Oy 2017 2 CONTENTS ABBREVIATIONS ........................................................................................................................................... 5 LIST OF ORIGINAL PUBLICATIONS ................................................................................................................. 6 ABSTRACT .................................................................................................................................................... 7 1. INTRODUCTION........................................................................................................................................ 8 1.1 Type III Polyketide synthases (PKS) ..................................................................................................... 8 1.1.1 Chalcone synthase (CHS) ............................................................................................................10 1.1.2 Stilbene synthase (STS) ...............................................................................................................12 1.1.3 2-pyrone synthase (2PS) .............................................................................................................12 1.1.4 Pentaketide chromonesynthase (PCS) and Octaketidesynthase (OKS) .........................................12 1.1.5 Anther specific chalcone synthases (ASCLs) ................................................................................13 1.2 Type III PKS structure and function ....................................................................................................14 1.2.1 Engineering plant polyketides .....................................................................................................15 1.2.2 Combinatorial biosynthesis.........................................................................................................16 1.3 Type III PKSs in the biosynthesis of plant secondary metabolites .......................................................16 1.3.1 The biosynthesis of 4-hydroxy-5-methylcoumarin (HMC)............................................................16 1.3.2 The biosynthesis of sporopollenin ..............................................................................................18 1.4 Glycosylation of plant metabolites ....................................................................................................20 1.4.1 The function of GTs ....................................................................................................................20 1.4.2 The physiological role of GTs ......................................................................................................21 1.4.3 Structure of GTs .........................................................................................................................21 1.4.4 Protein engineering of GTs and biotechnological applications.....................................................22 2. AIMS OF THE STUDY ................................................................................................................................23 3. MATERIALS AND METHODS ....................................................................................................................23 4. RESULTS AND DISCUSSION ......................................................................................................................24 4.1 Characterization of new 2PS enzymes, G2PS2 and G2PS3 from Gerbera hybrida ...............................24 4.1.1 In vitro enzymatic activity of G2PS2 and G2PS3 ..........................................................................24 4.1.2 G2PS2 and G2PS3 expression in planta .......................................................................................25 4.1.3 Active site of G2PS2 and G2PS3 ..................................................................................................25 4.1.4 Enzyme activity of mutated G2PS1 and G2PS2 ............................................................................26 4.1.5 Expression patterns of G2PS2 and G2PS3....................................................................................26 3 4.2 Functional characterization of GASCL1 and GASCL2, two ASCL enzymes from Gerbera hybrida .........27 4.2.1 In vitro enzyme activity of GASCL1 and GASCL2 ..........................................................................27 4.2.2 Expression of GASCL1 and GASCL2 ..............................................................................................29 4.3 Characterization of gerbera GTs ........................................................................................................30 4.3.1 In vitro activity of gerbera GTs ....................................................................................................30 4.3.2 Virus induced gene silencing of glucosyltransferases ..................................................................30 5. CONCLUSION AND FUTURE PROSPECTS ..................................................................................................32 6. ACKNOWLEDGEMENTS ...........................................................................................................................33 7. REFERENCES ...........................................................................................................................................34 4 ABBREVIATIONS 2PS 2-pyrone synthase ASCL Anther specific chalcone synthase ALS Aloesone synthase ANS Anthocyanidin synthase Asn Asparagine AT Acyl transferase BAS Benzalacetone synthase BIS Biphenyl synthase cDNA Complementary DNA CHI Chalcone isomerase CHS Chalcone synthase CoA Coenzyme A CUR Curcuminoid synthase Cys Cysteine DFR Dihydroflavonol reductase ESI-MS Electron spray ionization mass spectrometry FAS Fatty acid synthase F3H Flavanone 3ɴ-hydroxylase F3´H Flavanoid 3’-hydroxylase FLS Flavonol synthase FNS Flavone synthase GT Glycosyltransferase Gly Glysine TAL Triacetolactone His Histidine Ile Isoleucine HMC 4-hydroxy-5-methylcoumarin HPLC High performance liquid chromatography HR Hypersensitive response KAS Ketoacyl synthase LAR Leucoanthocyanidin reductase Leu Leucine OAC Olivetolic acid cyclase OARS Oxoalkylresorcinol synthase OKS Octaketide synthase PCR Polymerase chain reaction PCS Pentaketide chromone synthase Phe Phenylalanine PKR Polyketide reductase PKS Polyketide synthase SA Salicylic acid Ser Serine STCS Stilbenecarboxylate synthase STS Stillbene synthase TAL Triacetolactone Thr Threonine TLC Thin-layer chromatography TKPR Tetraketide-2-pyrone reductase TMV Tobacco Mosaic Virus Tyr Tyrosine UDP Uridine-diphosphate UPLC Ultra performance liquid chromatography VIGS Virus Induced Gene Silencing 5 LIST OF ORIGINAL PUBLICATIONS The thesis is based on the following publications: I *Pietiäinen M., *Kontturi J., Paasela., Deng X., Ainasoja M., Nyberg P., Hotti H., Teeri T. 2016. Two polyketide synthases are necessary for 4-hydroxy-5-methylcoumarin biosynthesis in Gerbera hybrida. Plant Journal, 87: 548-558. II Kontturi J., Osama R., Deng X., Bashandy H., Albert V.A., Teeri T.H. 2017. Functional characterization and expression of GASCL1 and GASCL2, two anther-specific chalcone synthase like enzymes from Gerbera hybrida. Phytochemistry, 134: 38-45. III Kontturi J., Lampio A., Deng X., Teeri T.H. Glucosyltransferases from Gerbera hybrida. Manuscript. *Shared first authorship Contribution to the articles I I did the cloning of PKS genes, protein production in E.coli, protein purification and in vitro enzymatic assays. I did all the HPLC runs from in vitro assays and tobacco infiltration results, and with the help of MS-laboratory, analyzed the MS-results from all experiments. I did the protein models, mutagenesis, and all the work relating to the mutated proteins and in vitro results. Finally, I analyzed the transgenic gerbera plants for HMC. I participated in planning the experiments, and wrote the article with Milla Pietiäinen under the supervision of Teemu Teeri. II I cloned the PKS-genes, made protein production in E.coli, protein purification and in vitro enzymatic assays. I screened the results with HPLC and with the help of MS-laboratory,