title: Three-Dimensional Visualization of the Tubular-Lamellar Transformation of the Internal Plastid Membrane Network during Runner Bean Chloroplast Biogenesis.
abstract: Chloroplast biogenesis is a complex process that is integrated with plant development, leading to fully differentiated and functionally mature plastids. In this work, we used electron tomography and confocal microscopy to reconstruct the process of structural membrane transformation during the etioplast-to-chloroplast transition in runner bean (Phaseolus coccineus). During chloroplast development, the regular tubular network of paracrystalline prolamellar bodies (PLBs) and the flattened porous membranes of prothylakoids develop into the chloroplast thylakoids. Three-dimensional reconstruction is required to provide us with a more complete understanding of this transformation. We provide spatial models of the bean chloroplast biogenesis that allow such reconstruction of the internal membranes of the developing chloroplast and visualize the transformation from the tubular arrangement to the linear system of parallel lamellae. We prove that the tubular structure of the PLB transforms directly to flat slats, without dispersion to vesicles. We demonstrate that the grana/stroma thylakoid connections have a helical character starting from the early stages of appressed membrane formation. Moreover, we point out the importance of particular chlorophyll-protein complex components in the membrane stacking during the biogenesis. The main stages of chloroplast internal membrane biogenesis are presented in a movie that shows the time development of the chloroplast biogenesis as a dynamic model of this process.
authors.affiliation: Department of Plant Anatomy and Cytology, Faculty of Biology, University of Warsaw, 02-096 Warsaw, Poland.
authors.forename: Łucja
authors.identifier: 0000-0002-4090-6291
authors.initials: Ł
authors.lastname: Kowalewska
authors.affiliation: Department of Metabolic Regulation, Faculty of Biology, University of Warsaw, 02-096 Warsaw, Poland.
authors.forename: Radosław
authors.identifier: 0000-0003-3615-1911
authors.initials: R
authors.lastname: Mazur
authors.affiliation: Laboratory of Electron Microscopy, Nencki Institute of Experimental Biology, Polish Academy of Sciences, 02-093 Warsaw, Poland.
authors.forename: Szymon
authors.initials: S
authors.lastname: Suski
authors.affiliation: Department of Metabolic Regulation, Faculty of Biology, University of Warsaw, 02-096 Warsaw, Poland.
authors.forename: Maciej
authors.identifier: 0000-0001-7141-505X
authors.initials: M
authors.lastname: Garstka
authors.affiliation: Department of Plant Anatomy and Cytology, Faculty of Biology, University of Warsaw, 02-096 Warsaw, Poland mostowag@biol.uw.edu.pl.
authors.forename: Agnieszka
authors.identifier: 0000-0003-4109-5125
authors.initials: A
authors.lastname: Mostowska
mesh_terms: D002734:Chlorophyll / Q000378:metabolism; D002736:Chloroplasts / Q000378:metabolism*; D021621:Imaging, Three-Dimensional / Q000379:methods*; D001678:Organelle Biogenesis; D027805:Phaseolus / Q000378:metabolism*; D018087:Plastids / Q000378:metabolism*
chemical_list: D002734:Chlorophyll