Ibl Verena, Kapusi Eszter, Arcalis Elsa, Kawagoe Yasushi, Stoger Eva
Department for Applied Genetics and Cell Biology, Molecular Plant Physiology and Crop Biotechnology, University of Natural Resources and Life Sciences, Muthgasse 18, 1190 Vienna, Austria.
Division of Plant Sciences, National Institute of Agrobiological Sciences, Tsukuba, 305-8602 Japan.
J Exp Bot. 2014 Jul;65(12):3249-61. doi: 10.1093/jxb/eru175. Epub 2014 May 6.
Cereal endosperm is a highly differentiated tissue containing specialized organelles for the accumulation of storage proteins. The endosperm of barley contains hordeins, which are ultimately deposited within protein storage vacuoles (PSVs). These organelles have been characterized predominantly by the histochemical analysis of fixed immature tissue samples. However, little is known about the fate of PSVs during barley endosperm development, and in vivo imaging has not been attempted in order to gain further insight. In this report, young seeds were followed through development to characterize the dynamic morphology of PSVs from aleurone, subaleurone, and central starchy endosperm cells. TIP3-GFP was used as a PSV membrane marker and several fluorescent tracers were used to identify membranes and monitor endomembrane organelles in real time. Whereas the spherical appearance of strongly labelled TIP3-GFP PSVs in the aleurone remained constant, those in the subaleurone and central starchy endosperm underwent substantial morphological changes. Fusion and rupture events were observed in the subaleurone, and internal membranes derived from both the tonoplast and endoplasmic reticulum were identified within these PSVs. TIP3-GFP-labelled PSVs in the starchy endosperm cells underwent a dramatic reduction in size, so that finally the protein bodies were tightly enclosed. Potential desiccation-related membrane-altering processes that may be causally linked to these dynamic endomembrane events in the barley endosperm are discussed.
谷物胚乳是一种高度分化的组织，含有用于储存蛋白积累的特殊细胞器。大麦胚乳含有大麦醇溶蛋白，最终沉积在蛋白储存液泡（PSV）中。这些细胞器主要通过对固定的未成熟组织样本进行组织化学分析来表征。然而，关于大麦胚乳发育过程中PSV的命运知之甚少，并且尚未尝试进行体内成像以获得更深入的了解。在本报告中，追踪了幼嫩种子的发育过程，以表征糊粉层、亚糊粉层和中央淀粉胚乳细胞中PSV的动态形态。TIP3-GFP用作PSV膜标记物，并使用几种荧光示踪剂实时识别膜并监测内膜细胞器。糊粉层中强烈标记的TIP3-GFP PSV的球形外观保持不变，而亚糊粉层和中央淀粉胚乳中的PSV则发生了显著的形态变化。在亚糊粉层中观察到融合和破裂事件，并且在这些PSV中鉴定出来自液泡膜和内质网的内膜。淀粉胚乳细胞中TIP3-GFP标记的PSV大小急剧减小，最终蛋白质体被紧密包裹。讨论了可能与大麦胚乳中这些动态内膜事件有因果关系的潜在干燥相关膜改变过程。
