Distinct Lytic Vacuolar Compartments are Embedded Inside the Protein Storage Vacuole of Dry and Germinating Arabidopsis thaliana Seeds
Distinct Lytic Vacuolar Compartments are Embedded Inside the Protein Storage Vacuole of Dry and Germinating Arabidopsis thaliana Seeds
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DOI：
10.1093/pcp/pcr065
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发表时间：
2011-07-01
影响因子：
4.9
通讯作者：
Thomine, Sebastien
中科院分区：
文献类型：
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作者：
Bolte, Susanne;Lanquar, Viviane;Thomine, Sebastien
植物细胞液泡是多样且动态的结构。特别是在种子萌发过程中，蛋白质储存液泡会迅速被一个中央溶酶体液泡取代，从而使胚细胞能够快速伸长。在这项研究中，我们利用针对液泡膜内在蛋白（TIP）异构体以及参与营养动员和液泡酸化的蛋白质的免疫细胞化学方法，研究了拟南芥种子萌发过程中液泡区室的动态重塑。我们的结果证实，在干燥种子的蛋白质储存液泡中存在一个由γ - TIP、液泡质子泵焦磷酸酶（V - PPase）和金属转运蛋白NRAMP4标记的溶酶体区室。它们进一步表明，这个区室在层积处理后消失。然后它被一个新形成的溶酶体区室取代，这个新的区室由γ - TIP和V - PPase标记，但没有AtNRAMP4，并且随着萌发的进行，它占据的体积更大。总之，我们的结果表明，在萌发的拟南芥细胞的蛋白质储存液泡中先后出现了两种不同的溶酶体区室。我们提出，第一个区室对应于专门用于矿物质储存的球状体，第二个区室是这些细胞中中央溶酶体液泡的起源。
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 gamma-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 gamma-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.