title: Expression levels of antimicrobial peptide tachyplesin I in transgenic Ornithogalum lines affect the resistance to Pectobacterium infection.
abstract: The genus Ornithogalum includes several ornamental species that suffer substantial losses from bacterial soft rot caused by Pectobacteria. The absence of effective control measures for use against soft rot bacteria led to the initiation of a project in which a small antimicrobial peptide from an Asian horseshoe crab, tachyplesin (tpnI), was introduced into two commercial cultivars: O. dubium and O. thyrsoides. Disease severity and bacterial colonization were examined in transgenic lines expressing this peptide. Disease resistance was evaluated in six lines of each species by measuring bacterial proliferation in the plant tissue. Three transgenic lines of each species were subjected to further analysis in which the expression level of the transgene was evaluated using RT-PCR and qRT-PCR. The development of disease symptoms and bacterial colonization of the plant tissue were also examined using GFP-expressing strain of P. carotovorum subsp. brasiliense Pcb3. Confocal-microscopy imaging revealed significantly reduced quantities of bacterial cells in the transgenic plant lines that had been challenged with the bacterium. The results clearly demonstrate that tpnI expression reduces bacterial proliferation, colonization and disease symptom (reduced by 95-100%) in the transgenic plant tissues. The quantity of tpnI transcripts, as measured by qRT-PCR, was negatively correlated with the protection afforded to the plants, as measured by the reduced severity of disease symptoms in the tissue.
authors.affiliation: Department of Plant Sciences, Agricultural Research Organization, The Volcani Center, Bet Dagan, Israel.
authors.forename: Alexander
authors.initials: A
authors.lastname: Lipsky
authors.affiliation: Department of Plant Sciences, Agricultural Research Organization, The Volcani Center, Bet Dagan, Israel; Department of Plant Pathology and Microbiology and the Otto Warburg Minerva Center for Agricultural Biotechnology, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, Israel.
authors.forename: Janak Raj
authors.initials: JR
authors.lastname: Joshi
authors.affiliation: Department of Plant Sciences, Agricultural Research Organization, The Volcani Center, Bet Dagan, Israel.
authors.forename: Nir
authors.initials: N
authors.lastname: Carmi
authors.affiliation: Department of Plant Sciences, Agricultural Research Organization, The Volcani Center, Bet Dagan, Israel. Electronic address: irisy@volcani.agri.gov.il.
authors.forename: Iris
authors.initials: I
authors.lastname: Yedidia
mesh_terms: D000890:Anti-Infective Agents / Q000737:chemistry / Q000378:metabolism* / Q000494:pharmacology; D023181:Antimicrobial Cationic Peptides / Q000737:chemistry / Q000235:genetics / Q000378:metabolism* / Q000494:pharmacology; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism* / Q000494:pharmacology; D024881:Drug Resistance, Bacterial / Q000187:drug effects; D031442:Ornithogalum / Q000235:genetics / Q000378:metabolism*; D044043:Pectobacterium / Q000187:drug effects*; D010456:Peptides, Cyclic / Q000737:chemistry / Q000235:genetics / Q000378:metabolism* / Q000494:pharmacology; D030821:Plants, Genetically Modified / Q000235:genetics / Q000378:metabolism*
chemical_list: D000890:Anti-Infective Agents; D023181:Antimicrobial Cationic Peptides; D004268:DNA-Binding Proteins; D010456:Peptides, Cyclic; C057636:tachyplesin peptide, Tachypleus tridentatus
keywords: Antimicrobial activity; Ornithogalum dubium; Ornithogalum thyrsoides; Pectobacterium; Tachyplesin; Transgenic plants