title: Salicylate and catechol levels are maintained in nahG transgenic poplar.
abstract: Metabolic profiling was used to investigate the molecular phenotypes of a transgenic Populus tremula x P. alba hybrid expressing the nahG transgene, a bacterial gene encoding salicylate hydroxylase that converts salicylic acid to catechol. Despite the efficacy of this transgenic approach to reduce salicylic acid levels in other model systems and thereby elucidate roles for salicylic acid in plant signaling, transgenic poplars had similar foliar levels of salicylic acid and catechol to that of non-transformed controls and exhibited no morphological phenotypes. To gain a deeper understanding of the basis for these observations, we analyzed metabolic profiles of leaves as influenced by transgene expression. Expression of nahG decreased quinic acid conjugates and increased catechol glucoside, while exerting little effect on levels of salicylic acid and catechol, the substrate and product, respectively, of the nahG enzyme. This suggests a biological role of elevated constitutive salicylic acid levels in Populus, in contrast to other plant systems in which nahG dramatically reduces salicylic acid levels.
authors.affiliation: School of Forest Resources and Conservation, University of Florida, P.O. Box 110410, Gainesville, FL 32611, USA. ammorse@ufl.edu
authors.forename: Alison M
authors.initials: AM
authors.lastname: Morse
authors.forename: Timothy J
authors.initials: TJ
authors.lastname: Tschaplinski
authors.forename: Christopher
authors.initials: C
authors.lastname: Dervinis
authors.forename: Paula M
authors.initials: PM
authors.lastname: Pijut
authors.forename: Eric A
authors.initials: EA
authors.lastname: Schmelz
authors.forename: Wendy
authors.initials: W
authors.lastname: Day
authors.forename: John M
authors.initials: JM
authors.lastname: Davis
mesh_terms: D001426:Bacterial Proteins / Q000096:biosynthesis / Q000235:genetics*; D015152:Blotting, Northern; D002396:Catechols / Q000302:isolation & purification / Q000378:metabolism*; D006899:Mixed Function Oxygenases / Q000096:biosynthesis / Q000235:genetics*; D030821:Plants, Genetically Modified / Q000201:enzymology / Q000235:genetics / Q000378:metabolism; D032107:Populus / Q000201:enzymology / Q000235:genetics / Q000378:metabolism; D018749:RNA, Plant / Q000235:genetics; D012459:Salicylates / Q000302:isolation & purification / Q000378:metabolism*; D019076:Transgenes
chemical_list: D001426:Bacterial Proteins; D002396:Catechols; D018749:RNA, Plant; D012459:Salicylates; D006899:Mixed Function Oxygenases; C022619:salicylate 1-monooxygenase; C034221:catechol