title: Effects of brefeldin A on the endomembrane system and germ tube formation of the tetraspore of Gelidium floridanum (Rhodophyta, Florideophyceae).
abstract: Gelidium floridanum W.R. Taylor tetraspores are units of dispersal and are responsible for substrate attachment. This study aimed to examine evidence of direct interaction between germ tube formation and Golgi activity during tetraspore germination of G. floridanum. After release, the tetraspores were incubated with brefeldin A (BFA) in concentrations of 4 and 8 μM over a 6 h period. The controls and treatments were analyzed with light, fluorescence (FM4-64 dye) and transmission electron microscopy. In the control samples, the Golgi bodies were responsible for germ tube formation. In contrast, BFA-treated samples were observed to inhibit spore adhesion and germ tube formation. These tetraspores also showed an increase in volume (≥30 μm width). BFA treatment also resulted in the disassembly of Golgi cisternae and the formation of vesiculated areas of the cytoplasm, blocking the secretion of protein and amorphous matrix polysaccharides. When stained with FM4-64, the control samples showed fluorescence in the apical region of the germ tube, but the treated samples showed an intense fluorescence throughout the cytoplasm. From these results, we can conclude that the germ tube is formed by the incorporation of vesicles derived from Golgi. Thus, vesicle secretion and Golgi organization are basic processes and essential in adhesion and tube formation. By blocking the secretion of protein and amorphous matrix polysaccharides, BFA treatment precluded tetraspore germination.
authors.affiliation: Plant Cell Biology Laboratory, Department of Cell Biology, Embryology and Genetics, Federal University of Santa Catarina, CP 476, Florianópolis, Santa Catarina, 88049-900, Brazil.|Central Laboratory of Electron Microscopy, Federal University of Santa Catarina, CP 476, Florianópolis, Santa Catarina, 88049-900, Brazil.
authors.forename: Carmen
authors.initials: C
authors.lastname: Simioni
authors.affiliation: Plant Cell Biology Laboratory, Department of Cell Biology, Embryology and Genetics, Federal University of Santa Catarina, CP 476, Florianópolis, Santa Catarina, 88049-900, Brazil.|Central Laboratory of Electron Microscopy, Federal University of Santa Catarina, CP 476, Florianópolis, Santa Catarina, 88049-900, Brazil.
authors.forename: Ticiane
authors.initials: T
authors.lastname: Rover
authors.affiliation: Plant Cell Biology Laboratory, Department of Cell Biology, Embryology and Genetics, Federal University of Santa Catarina, CP 476, Florianópolis, Santa Catarina, 88049-900, Brazil.|Central Laboratory of Electron Microscopy, Federal University of Santa Catarina, CP 476, Florianópolis, Santa Catarina, 88049-900, Brazil.
authors.forename: Éder C
authors.initials: ÉC
authors.lastname: Schmidt
authors.affiliation: Plant Cell Biology Laboratory, Department of Cell Biology, Embryology and Genetics, Federal University of Santa Catarina, CP 476, Florianópolis, Santa Catarina, 88049-900, Brazil.|Central Laboratory of Electron Microscopy, Federal University of Santa Catarina, CP 476, Florianópolis, Santa Catarina, 88049-900, Brazil.
authors.forename: Marthiellen R
authors.initials: MR
authors.lastname: de L Felix
authors.affiliation: Plant Cell Biology Laboratory, Department of Cell Biology, Embryology and Genetics, Federal University of Santa Catarina, CP 476, Florianópolis, Santa Catarina, 88049-900, Brazil.|Central Laboratory of Electron Microscopy, Federal University of Santa Catarina, CP 476, Florianópolis, Santa Catarina, 88049-900, Brazil.
authors.forename: Luz Karime
authors.initials: LK
authors.lastname: Polo
authors.affiliation: Plant Cell Biology Laboratory, Department of Cell Biology, Embryology and Genetics, Federal University of Santa Catarina, CP 476, Florianópolis, Santa Catarina, 88049-900, Brazil.|Central Laboratory of Electron Microscopy, Federal University of Santa Catarina, CP 476, Florianópolis, Santa Catarina, 88049-900, Brazil.
authors.forename: Rodrigo Dos
authors.initials: RD
authors.lastname: Santos
authors.affiliation: Plant Cell Biology Laboratory, Department of Cell Biology, Embryology and Genetics, Federal University of Santa Catarina, CP 476, Florianópolis, Santa Catarina, 88049-900, Brazil.|Central Laboratory of Electron Microscopy, Federal University of Santa Catarina, CP 476, Florianópolis, Santa Catarina, 88049-900, Brazil.
authors.forename: Giulia Burle
authors.initials: GB
authors.lastname: Costa
authors.affiliation: Plant Cell Biology Laboratory, Department of Cell Biology, Embryology and Genetics, Federal University of Santa Catarina, CP 476, Florianópolis, Santa Catarina, 88049-900, Brazil.|Central Laboratory of Electron Microscopy, Federal University of Santa Catarina, CP 476, Florianópolis, Santa Catarina, 88049-900, Brazil.
authors.forename: Marianne
authors.initials: M
authors.lastname: Kreusch
authors.affiliation: Plant Cell Biology Laboratory, Department of Cell Biology, Embryology and Genetics, Federal University of Santa Catarina, CP 476, Florianópolis, Santa Catarina, 88049-900, Brazil.|Central Laboratory of Electron Microscopy, Federal University of Santa Catarina, CP 476, Florianópolis, Santa Catarina, 88049-900, Brazil.
authors.forename: Debora T
authors.initials: DT
authors.lastname: Pereira
authors.affiliation: Plant Cell Biology Laboratory, Department of Cell Biology, Embryology and Genetics, Federal University of Santa Catarina, CP 476, Florianópolis, Santa Catarina, 88049-900, Brazil.|Central Laboratory of Electron Microscopy, Federal University of Santa Catarina, CP 476, Florianópolis, Santa Catarina, 88049-900, Brazil.
authors.forename: Luciane C
authors.initials: LC
authors.lastname: Ouriques
authors.affiliation: Plant Cell Biology Laboratory, Department of Cell Biology, Embryology and Genetics, Federal University of Santa Catarina, CP 476, Florianópolis, Santa Catarina, 88049-900, Brazil.|Central Laboratory of Electron Microscopy, Federal University of Santa Catarina, CP 476, Florianópolis, Santa Catarina, 88049-900, Brazil.
authors.forename: Zenilda L
authors.initials: ZL
authors.lastname: Bouzon
keywords: Gelidium floridanum; Golgi bodies; brefeldin A; electron microscopy; tetraspore germination