title: Production and diffusion of chloroplastic H2O2 and its implication to signalling.
abstract: Hydrogen peroxide (H(2)O(2)) is recognized as an important signalling molecule. There are two important aspects to this function: H(2)O(2) production and its diffusion to its sites of action. The production of H(2)O(2) by photosynthetic electron transport and its ability to diffuse through the chloroplast envelope membranes has been investigated using spin trapping electron paramagnetic resonance spectroscopy and H(2)O(2)-sensitive fluorescence dyes. It was found that, even at low light intensity, a portion of H(2)O(2) produced inside the chloroplasts can leave the chloroplasts thus escaping the effective antioxidant systems located inside the chloroplast. The production of H(2)O(2) by chloroplasts and the appearance of H(2)O(2) outside chloroplasts increased with increasing light intensity and time of illumination. The amount of H(2)O(2) that can be detected outside the chloroplasts has been shown to be up to 5% of the total H(2)O(2) produced inside the chloroplasts at high light intensities. The fact that H(2)O(2) produced by chloroplasts can be detected outside these organelles is an important finding in terms of understanding how chloroplastic H(2)O(2) can serve as a signal molecule.
authors.affiliation: CEA Saclay, iBiTec-S, CNRS URA 2096, Service de Bioénergétique Biologie Structurales et Mécanismes, F-91191 Gif-sur-Yvette Cedex, France. mubarakshinamm@gmail.com
authors.forename: Maria M
authors.initials: MM
authors.lastname: Mubarakshina
authors.forename: Boris N
authors.initials: BN
authors.lastname: Ivanov
authors.forename: Ilya A
authors.initials: IA
authors.lastname: Naydov
authors.forename: Warwick
authors.initials: W
authors.lastname: Hillier
authors.forename: Murray R
authors.initials: MR
authors.lastname: Badger
authors.forename: Anja
authors.initials: A
authors.lastname: Krieger-Liszkay
mesh_terms: D017360:Arabidopsis / Q000378:metabolism / Q000502:physiology; D002736:Chloroplasts / Q000378:metabolism*; D004058:Diffusion; D004578:Electron Spin Resonance Spectroscopy; D006861:Hydrogen Peroxide / Q000378:metabolism*; D010788:Photosynthesis / Q000502:physiology; D018515:Plant Leaves / Q000378:metabolism; D015398:Signal Transduction; D018724:Spinacia oleracea / Q000378:metabolism / Q000502:physiology; D020524:Thylakoids / Q000378:metabolism
chemical_list: D006861:Hydrogen Peroxide