title: Differences in the kinetics and scale of signalling molecule production modulate the ozone sensitivity of hybrid poplar clones: the roles of H2O2, ethylene and salicylic acid.
abstract: Hydrogen peroxide (H(2)O(2)), ethylene, 1-aminocyclopropane-1-carboxylic acid (ACC) and salicylic acid (SA) concentrations and ACC synthase (ACS) gene expression were measured to establish whether the high sensitivity of the Populus deltoides x maximowiczii clone Eridano to ozone (O(3)) exposure, compared with the O(3)-resistant Populus deltoides x euramericana clone I-214, is attributable to differences in the modulation of signal transduction pathways. In a time-course experiment, Populus deltoides (poplar) clones were exposed to acute fumigation with 150 nl l(-1) O(3) for 5 h. The two poplar clones showed differences in ethylene evolution, I-214 displaying earlier and less pronounced ethylene emission than Eridano. In both clones, ethylene evolution was accompanied by increased ACS transcript levels and enhanced emission of free ACC. I-214 exhibited a greater basal concentration of free SA and a lower concentration of the conjugated pool. However, a slight accumulation of free SA at the end of the 5-h exposure was found only in Eridano, together with an earlier minimal increase in the concentration of conjugated SA. The results show that both clones react to O(3) by producing H(2)O(2), ethylene and SA, but the difference in sensitivity to the pollutant is probably attributable to differences in the kinetics and magnitude of this response.
authors.affiliation: Department of Crop Plant Biology, University of Pisa, Italy.
authors.forename: Cecilia
authors.initials: C
authors.lastname: Diara
authors.forename: Antonella
authors.initials: A
authors.lastname: Castagna
authors.forename: Barbara
authors.initials: B
authors.lastname: Baldan
authors.forename: Anna Mensuali
authors.initials: AM
authors.lastname: Sodi
authors.forename: Tobias
authors.initials: T
authors.lastname: Sahr
authors.forename: Christian
authors.initials: C
authors.lastname: Langebartels
authors.forename: Luca
authors.initials: L
authors.lastname: Sebastiani
authors.forename: Annamaria
authors.initials: A
authors.lastname: Ranieri
mesh_terms: D001483:Base Sequence; D018744:DNA, Plant / Q000235:genetics; D005030:Ethylenes / Q000378:metabolism; D015870:Gene Expression / Q000187:drug effects; D017343:Genes, Plant / Q000187:drug effects; D006861:Hydrogen Peroxide / Q000378:metabolism; D007700:Kinetics; D008190:Lyases / Q000235:genetics; D010126:Ozone / Q000633:toxicity*; D032107:Populus / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism*; D020156:Salicylic Acid / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects
chemical_list: D018744:DNA, Plant; D005030:Ethylenes; D010126:Ozone; C036216:ethylene; D006861:Hydrogen Peroxide; D008190:Lyases; C021773:1-aminocyclopropanecarboxylate synthase; D020156:Salicylic Acid