New insights into the tonoplast architecture of plant vacuoles and vacuolar dynamics during osmotic stress
New insights into the tonoplast architecture of plant vacuoles and vacuolar dynamics during osmotic stress
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DOI：
10.1186/1471-2229-5-13
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发表时间：
2005-08-04
影响因子：
5.3
通讯作者：
Leborgne-Castel, Nathalie
中科院分区：
文献类型：
--
作者：
Reisen, Daniel;Marty, Francis;Leborgne-Castel, Nathalie
背景：营养植物液泡占成熟植物细胞体积的90%。液泡在调节细胞稳态和细胞生长中起着重要作用。液泡的组成及其体积的调节取决于液泡周围膜（称为液泡体）中转运蛋白和通道的协调活动。虽然对张力质体蛋白复合物的研究很好，但对张力质体本身的描述却不太好。为了进一步了解液泡是如何在植物细胞内折叠的，我们展示了烟草悬浮细胞中液泡的三维重建，这些液泡表达了细胞质水通道蛋白融合基因BobTIP26-1::gfp。结果：细胞液泡的三维重建可以准确分析在正常和应力条件下液泡膜的大跨越褶皱，并提示周围质体之间的相互作用。在不同生长条件下监测的烟草悬浮细胞中液泡的动态、高分辨率三维图像提供了液泡结构的额外细节。gfp装饰的液泡是一个单一的连续室，由管状的跨液泡链和大的膜表面横切。在渗透胁迫下的细胞培养导致了一个复杂的液泡网络，并增加了细胞质表面积。深入的三维现实检测表明，液泡的统一性在适应渗透胁迫的过程中得以保持。在逆境适应过程中表现出的液泡统一性，加上液泡与其他细胞器的密切联系，表明液泡在植物细胞中分别在代谢和液泡与细胞器之间的通信中发挥了生理作用。由聚乙二醇处理引起的干燥应力在液泡内产生“双”膜结构，与液泡内的质体紧密相连。当细胞恢复正常生长条件时，这些膜结构可以作为膜还原的膜库。结论：gfp标记的舌质体的三维处理提供了引人注目的植物细胞液泡视觉结构，并阐述了舌质体折叠和结构的本质。此外，这些方法可以实时测定应力期间的膜重排。
Background: The vegetative plant vacuole occupies > 90% of the volume in mature plant cells. Vacuoles play fundamental roles in adjusting cellular homeostasis and allowing cell growth. The composition of the vacuole and the regulation of its volume depend on the coordinated activities of the transporters and channels localized in the membrane (named tonoplast) surrounding the vacuole. While the tonoplast protein complexes are well studied, the tonoplast itself is less well described. To extend our knowledge of how the vacuole folds inside the plant cell, we present three-dimensional reconstructions of vacuoles from tobacco suspension cells expressing the tonoplast aquaporin fusion gene BobTIP26-1::gfp.Results: 3-D reconstruction of the cell vacuole made possible an accurate analysis of large spanning folds of the vacuolar membrane under both normal and stressed conditions, and suggested interactions between surrounding plastids. Dynamic, high resolution 3-D pictures of the vacuole in tobacco suspension cells monitored under different growth conditions provide additional details about vacuolar architecture. The GFP-decorated vacuole is a single continuous compartment transected by tubular-like transvacuolar strands and large membrane surfaces. Cell culture under osmotic stress led to a complex vacuolar network with an increased tonoplast surface area. In-depth 3-D realistic inspections showed that the unity of the vacuole is maintained during acclimation to osmotic stress. Vacuolar unity exhibited during stress adaptation, coupled with the intimate associations of vacuoles with other organelles, suggests a physiological role for the vacuole in metabolism, and communication between the vacuole and organelles, respectively, in plant cells. Desiccation stress ensuing from PEG treatment generates "double" membrane structures closely linked to the tonoplast within the vacuole. These membrane structures may serve as membrane reservoirs for membrane reversion when cells are reintroduced to normal growth conditions.Conclusion: 3-D processing of a GFP-labeled tonoplast provides compelling visual constructions of the plant cell vacuole and elaborates on the nature of tonoplast folding and architecture. Furthermore, these methods allow real-time determination of membrane rearrangements during stresses.