Barta, Csengele , Brilli, Federico , Fortunati, Alessio , Behnke, Katia , Schnitzler, Joerg-Peter , Loreto, Francesco .
Does isoprene play a role in the adaptation of leaves to elevated leaves of ultraviolet radiation by modulating the intra-foliar generation of reactive oxygen species (ROS)?
The depletion of the stratospheric ozone layer, which selectively absorbs part of the UV-B radiation - is a source of concerns about the impact of changes in the solar radiation spectrum and increased UV fluxes on the biota (Kerr et al., 1993, Science 262: 1032). UV radiation causes radical mediated oxidative stress in plants (Tevini, 1988, J. Photochem. Photobiol. B. Biol. 2(3): 401, Caldwell et al., 2003, J. Exp. Bot. 54(384): 879, Barta et al., 2004, Functional Plant Biol. 31:23.). Plant tolerance and acclimation to UV?B mainly depends on the balance between the damaging reactions and antioxidant efficiency or repair responses. Isoprene was hypothesized to protect plants against various environmental stresses by either stabilizing membranes or neutralizing the damaging reactive oxygen species (ROS) (Sharkey, T.D. and Singsaas, E.L. (1995) Nature 374:769., Loreto et al., 2001, Plant Physiol. 126: 993., Velikova et al., 2004, Physiol. Plant. 122: 219.). We studied whether the presence of isoprene aids plant tolerance to elevated UV radiation levels in isoprene emitting Populus plants as compared to transformed plants in which isoprene emission was suppressed. UV stress induced ROS were detected upon fluorescent labeling by confocal laser scanning microscopy. We show, that besides being less damaged by UV radiation, in isoprene emitting leaves less cellular membrane damage-related lipid-peroxyl radicals and reactive oxygen species are generated in different cellular compartments, than in non emitting leaves. We also demonstrate that either steady state or UV stress induced ROS production in leaves is strongly influenced by the presence of endogenous isoprene, influencing as well the accumulation of UV screening pigments, conferring an ability for elevated survival rates to emitting leaves as compared to non emitting ones. (Supported by ISONET, MRTN-CT-2003-504720 and VOCBAS Exchange Grant)
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1 - Italian National Research Council (CNR), Agroenvironment and Forest Biology (IBAF), Via Salaria Km 29,300, Monterotondo Scalo (Roma), 00016, Italy
2 - Italian National Research Council (CNR), Agroenvironment and Forest Biology Institute (IBAF),
3 - Italian National Research Council (CNR), Agroenvironment and Forest Biology Institute (IBAF)
4 - Forschungszentrum Karlsruhe, Institut für Meteorologie und Klimaforschung (IMK-IFU)
5 - Italian National Research Council (CNR), Agroenvironment and Forest Biology (IBAF)
reactive oxygen species
Presentation Type: Plant Biology Abstract
Location: Exhibit Hall (Northeast, Southwest & Southeast)/Hilton
Date: Sunday, July 8th, 2007
Time: 8:00 AM