Distinct Lytic Vacuolar Compartments are Embedded Inside the Protein Storage Vacuole of Dry and Germinating Arabidopsis thaliana Seeds

• Published in: Plant and cell physiology Vol. 52; no. 7; pp. 1142 - 1152
• Main Authors: Bolte, Susanne, Lanquar, Viviane, Soler, Marie-Noëlle, Beebo, Azeez, Satiat-Jeunemaître, Béatrice, Bouhidel, Karim, Thomine, Sébastien
• Format: Journal Article
• Language: English
• Published: Japan Oxford University Press 01.07.2011; Oxford University Press (OUP)
• Subjects: Aquaporins; Aquaporins - metabolism; Arabidopsis; Arabidopsis - cytology; Arabidopsis - metabolism; Arabidopsis Proteins; Arabidopsis Proteins - metabolism; Biological Sciences; Biologiska vetenskaper; Cation Transport Proteins; Cation Transport Proteins - metabolism; Desiccation; Germination; Life Sciences; Plant Proteins; Plant Proteins - metabolism; Protein Isoforms; Protein Isoforms - metabolism; Protein Transport; Seeds; Seeds - cytology; Seeds - growth & development; Vacuolar Proton-Translocating ATPases; Vacuolar Proton-Translocating ATPases - metabolism; Vacuoles; Vacuoles - metabolism; Vegetal Biology; Vacuole; Arabidopsis; Germination; Seed; TONOPLAST INTRINSIC PROTEIN; MOBILIZATION; PYROPHOSPHATASE; MEMBRANE; PREVACUOLAR COMPARTMENT; PLANT-CELLS; UNIQUE; TRANSPORT; IN-VIVO; H+-ATPASE
• ISSN: 0032-0781; 1471-9053
• DOI: 10.1093/pcp/pcr065

Plant cell vacuoles are diverse and dynamic structures. In particular, during seed germination, the protein storage vacuoles are rapidly replaced by a central lytic vacuole enabling rapid elongation of embryo cells. In this study, we investigate the dynamic remodeling of vacuolar compartments during Arabidopsis seed germination using immunocytochemistry with antibodies against tonoplast intrinsic protein (TIP) isoforms as well as proteins involved in nutrient mobilization and vacuolar acidification. Our results confirm the existence of a lytic compartment embedded in the protein storage vacuole of dry seeds, decorated by γ-TIP, the vacuolar proton pumping pyrophosphatase (V-PPase) and the metal transporter NRAMP4. They further indicate that this compartment disappears after stratification. It is then replaced by a newly formed lytic compartment, labeled by γ-TIP and V-PPase but not AtNRAMP4, which occupies a larger volume as germination progresses. Altogether, our results indicate the successive occurrence of two different lytic compartments in the protein storage vacuoles of germinating Arabidopsis cells. We propose that the first one corresponds to globoids specialized in mineral storage and the second one is at the origin of the central lytic vacuole in these cells.