title: Fusion, rupture, and degeneration: the fate of in vivo-labelled PSVs in developing barley endosperm.
abstract: Cereal endosperm is a highly differentiated tissue containing specialized organelles for the accumulation of storage proteins. The endosperm of barley contains hordeins, which are ultimately deposited within protein storage vacuoles (PSVs). These organelles have been characterized predominantly by the histochemical analysis of fixed immature tissue samples. However, little is known about the fate of PSVs during barley endosperm development, and in vivo imaging has not been attempted in order to gain further insight. In this report, young seeds were followed through development to characterize the dynamic morphology of PSVs from aleurone, subaleurone, and central starchy endosperm cells. TIP3-GFP was used as a PSV membrane marker and several fluorescent tracers were used to identify membranes and monitor endomembrane organelles in real time. Whereas the spherical appearance of strongly labelled TIP3-GFP PSVs in the aleurone remained constant, those in the subaleurone and central starchy endosperm underwent substantial morphological changes. Fusion and rupture events were observed in the subaleurone, and internal membranes derived from both the tonoplast and endoplasmic reticulum were identified within these PSVs. TIP3-GFP-labelled PSVs in the starchy endosperm cells underwent a dramatic reduction in size, so that finally the protein bodies were tightly enclosed. Potential desiccation-related membrane-altering processes that may be causally linked to these dynamic endomembrane events in the barley endosperm are discussed.
authors.affiliation: Department for Applied Genetics and Cell Biology, Molecular Plant Physiology and Crop Biotechnology, University of Natural Resources and Life Sciences, Muthgasse 18, 1190 Vienna, Austria.
authors.forename: Verena
authors.initials: V
authors.lastname: Ibl
authors.affiliation: Department for Applied Genetics and Cell Biology, Molecular Plant Physiology and Crop Biotechnology, University of Natural Resources and Life Sciences, Muthgasse 18, 1190 Vienna, Austria.
authors.forename: Eszter
authors.initials: E
authors.lastname: Kapusi
authors.affiliation: Department for Applied Genetics and Cell Biology, Molecular Plant Physiology and Crop Biotechnology, University of Natural Resources and Life Sciences, Muthgasse 18, 1190 Vienna, Austria.
authors.forename: Elsa
authors.initials: E
authors.lastname: Arcalis
authors.affiliation: Division of Plant Sciences, National Institute of Agrobiological Sciences, Tsukuba, 305-8602 Japan.
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Kawagoe
authors.affiliation: Department for Applied Genetics and Cell Biology, Molecular Plant Physiology and Crop Biotechnology, University of Natural Resources and Life Sciences, Muthgasse 18, 1190 Vienna, Austria eva.stoger@boku.ac.at.
authors.forename: Eva
authors.initials: E
authors.lastname: Stoger
mesh_terms: D004721:Endoplasmic Reticulum / Q000378:metabolism; D056625:Endosperm / Q000254:growth & development* / Q000378:metabolism; D049452:Green Fluorescent Proteins / Q000378:metabolism; D001467:Hordeum / Q000254:growth & development* / Q000378:metabolism*; D008565:Membrane Proteins / Q000378:metabolism; D018613:Microscopy, Confocal; D010940:Plant Proteins / Q000378:metabolism*; D011994:Recombinant Proteins / Q000378:metabolism; D012639:Seeds / Q000254:growth & development / Q000378:metabolism; D014617:Vacuoles / Q000378:metabolism
chemical_list: D008565:Membrane Proteins; D010940:Plant Proteins; D011994:Recombinant Proteins; C077491:tonoplast intrinsic protein, plant; D049452:Green Fluorescent Proteins
keywords: Cereal seed; TIP3.; endomembrane system; endosperm; protein storage vacuole