title: Knocking Down of Isoprene Emission Modifies the Lipid Matrix of Thylakoid Membranes and Influences the Chloroplast Ultrastructure in Poplar.
abstract: Isoprene is a small lipophilic molecule with important functions in plant protection against abiotic stresses. Here, we studied the lipid composition of thylakoid membranes and chloroplast ultrastructure in isoprene-emitting (IE) and nonisoprene-emitting (NE) poplar (Populus × canescens). We demonstrated that the total amount of monogalactosyldiacylglycerols, digalactosyldiacylglycerols, phospholipids, and fatty acids is reduced in chloroplasts when isoprene biosynthesis is blocked. A significantly lower amount of unsaturated fatty acids, particularly linolenic acid in NE chloroplasts, was associated with the reduced fluidity of thylakoid membranes, which in turn negatively affects photosystem II photochemical efficiency. The low photosystem II photochemical efficiency in NE plants was negatively correlated with nonphotochemical quenching and the energy-dependent component of nonphotochemical quenching. Transmission electron microscopy revealed alterations in the chloroplast ultrastructure in NE compared with IE plants. NE chloroplasts were more rounded and contained fewer grana stacks and longer stroma thylakoids, more plastoglobules, and larger associative zones between chloroplasts and mitochondria. These results strongly support the idea that in IE species, the function of this molecule is closely associated with the structural organization and functioning of plastidic membranes.
authors.affiliation: Institute of Plant Physiology and Genetics, Bulgarian Academy of Sciences, Sofia 1113, Bulgaria (V.V.); andResearch Unit Analytical BioGeoChemistry (C.M., T.M.R., P.S.-K.), Research Unit Environmental Simulation, Institute of Biochemical Plant Pathology (V.V., A.G., J.-P.S.), and Research Unit Analytical Pathology (M.A., A.W.), Helmholtz Zentrum München, 85764 Neuherberg, Germany.
authors.forename: Violeta
authors.initials: V
authors.lastname: Velikova
authors.affiliation: Institute of Plant Physiology and Genetics, Bulgarian Academy of Sciences, Sofia 1113, Bulgaria (V.V.); andResearch Unit Analytical BioGeoChemistry (C.M., T.M.R., P.S.-K.), Research Unit Environmental Simulation, Institute of Biochemical Plant Pathology (V.V., A.G., J.-P.S.), and Research Unit Analytical Pathology (M.A., A.W.), Helmholtz Zentrum München, 85764 Neuherberg, Germany.
authors.forename: Constanze
authors.initials: C
authors.lastname: Müller
authors.affiliation: Institute of Plant Physiology and Genetics, Bulgarian Academy of Sciences, Sofia 1113, Bulgaria (V.V.); andResearch Unit Analytical BioGeoChemistry (C.M., T.M.R., P.S.-K.), Research Unit Environmental Simulation, Institute of Biochemical Plant Pathology (V.V., A.G., J.-P.S.), and Research Unit Analytical Pathology (M.A., A.W.), Helmholtz Zentrum München, 85764 Neuherberg, Germany.
authors.forename: Andrea
authors.initials: A
authors.lastname: Ghirardo
authors.affiliation: Institute of Plant Physiology and Genetics, Bulgarian Academy of Sciences, Sofia 1113, Bulgaria (V.V.); andResearch Unit Analytical BioGeoChemistry (C.M., T.M.R., P.S.-K.), Research Unit Environmental Simulation, Institute of Biochemical Plant Pathology (V.V., A.G., J.-P.S.), and Research Unit Analytical Pathology (M.A., A.W.), Helmholtz Zentrum München, 85764 Neuherberg, Germany.
authors.forename: Theresa Maria
authors.initials: TM
authors.lastname: Rock
authors.affiliation: Institute of Plant Physiology and Genetics, Bulgarian Academy of Sciences, Sofia 1113, Bulgaria (V.V.); andResearch Unit Analytical BioGeoChemistry (C.M., T.M.R., P.S.-K.), Research Unit Environmental Simulation, Institute of Biochemical Plant Pathology (V.V., A.G., J.-P.S.), and Research Unit Analytical Pathology (M.A., A.W.), Helmholtz Zentrum München, 85764 Neuherberg, Germany.
authors.forename: Michaela
authors.initials: M
authors.lastname: Aichler
authors.affiliation: Institute of Plant Physiology and Genetics, Bulgarian Academy of Sciences, Sofia 1113, Bulgaria (V.V.); andResearch Unit Analytical BioGeoChemistry (C.M., T.M.R., P.S.-K.), Research Unit Environmental Simulation, Institute of Biochemical Plant Pathology (V.V., A.G., J.-P.S.), and Research Unit Analytical Pathology (M.A., A.W.), Helmholtz Zentrum München, 85764 Neuherberg, Germany.
authors.forename: Axel
authors.initials: A
authors.lastname: Walch
authors.affiliation: Institute of Plant Physiology and Genetics, Bulgarian Academy of Sciences, Sofia 1113, Bulgaria (V.V.); andResearch Unit Analytical BioGeoChemistry (C.M., T.M.R., P.S.-K.), Research Unit Environmental Simulation, Institute of Biochemical Plant Pathology (V.V., A.G., J.-P.S.), and Research Unit Analytical Pathology (M.A., A.W.), Helmholtz Zentrum München, 85764 Neuherberg, Germany.
authors.forename: Philippe
authors.initials: P
authors.lastname: Schmitt-Kopplin
authors.affiliation: Institute of Plant Physiology and Genetics, Bulgarian Academy of Sciences, Sofia 1113, Bulgaria (V.V.); andResearch Unit Analytical BioGeoChemistry (C.M., T.M.R., P.S.-K.), Research Unit Environmental Simulation, Institute of Biochemical Plant Pathology (V.V., A.G., J.-P.S.), and Research Unit Analytical Pathology (M.A., A.W.), Helmholtz Zentrum München, 85764 Neuherberg, Germany jp.schnitzler@helmholtz-muenchen.de.
authors.forename: Jörg-Peter
authors.identifier: http://orcid.org/0000-0002-9825-867X
authors.initials: JP
authors.lastname: Schnitzler
mesh_terms: D002070:Butadienes / Q000378:metabolism*; D002734:Chlorophyll / Q000378:metabolism; D005227:Fatty Acids / Q000378:metabolism; D005453:Fluorescence; D055785:Gene Knockdown Techniques; D045782:Hemiterpenes / Q000378:metabolism*; D016018:Least-Squares Analysis; D008055:Lipids / Q000737:chemistry*; D008315:Malondialdehyde / Q000378:metabolism; D008954:Models, Biological; D015999:Multivariate Analysis; D010084:Oxidation-Reduction; D010420:Pentanes / Q000378:metabolism*; D010788:Photosynthesis; D045332:Photosystem II Protein Complex / Q000378:metabolism; D010940:Plant Proteins / Q000378:metabolism; D032107:Populus / Q000378:metabolism* / Q000648:ultrastructure*; D020524:Thylakoids / Q000378:metabolism* / Q000648:ultrastructure*
chemical_list: D002070:Butadienes; D005227:Fatty Acids; D045782:Hemiterpenes; D008055:Lipids; D010420:Pentanes; D045332:Photosystem II Protein Complex; D010940:Plant Proteins; C005059:isoprene; D002734:Chlorophyll; D008315:Malondialdehyde