Characterization of EXPO and EVs in Plants: A Combination of 3D Tomography and CLEM Approach
Invited conference paper presented and published in conference proceedings
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AbstractDistinct from mammalian cells, plant cells contain cell wall that would prevent the formation and function of extracellular vesicles (EVs). However, recent studies indicated that plants also contained EVs, including EVs (size at 10-300 nm in diameter) isolated from the apoplastic fluids of pathogen-affected Arabidopsis leaves via centrifugation (Rutter et al., 2017) and the novel double-membrane structure termed EXPO (exocyst-positive organelle) which is distinct from the autophagosome and may represent an unconventional protein secretion (UPS) pathway in plants (Wang et al., 2010; Ding et al., 2014a/b; Lin et al., 2015). However, the nature and function of EVs and EXPO remain elusive in plants. In this study, we have used a combination of 3D Electron Tomography (ET) and Correlative Light and Electron Microscopy (CLEM) to study the nature and identity of EVs and EXPO in different cell types of both wild type (WT) and transgenic Arabidopsis plants expressing the EXPO marker Exo70E2. We have made great progress in this project with novel findings: 1) We demonstrated the existence of EVs in intact plant cells via 3D ET analyses; 2) The most abundant EVs were located in the apoplast of some cell types; 3) A detailed analysis of certain small EVs (size at 30-200 nm in diameter) showed that their internal contents were electron-transparent; 4) 3D tomography and immuno-EM results showed that the plant-unique EXPO (size at 200-500 nm in diameter) contained identical cytoplasmic contents including ribosomes; and 5) The CLEM analyses further distinguished the Exo70E2-positive EXPO from other types of EVs in term of size, shape and cargo contents in the root apoplast. On-going studies focus on addressing the physiological responses and functional implications of these EVs and EXPO in plants. Here we will present an update on this study on the nature and function of EXPO and EVs in plants. Supported by grants from the Research Grants Council of Hong Kong (CUHK14130716, 14102417, C4011-14R, C4012-16E, C4002-17G and AoE/M-05/12), the National Natural Science Foundation of China (31270226 and 31470294).
All Author(s) ListYong Cui, Jiayang Gao, Yilin He, Wenhan Cao, Liwen Jiang
Name of Conference2018 CSH Asia Meeting on “Biology of Extracellular Vesicles”
Start Date of Conference12/11/2018
End Date of Conference16/11/2018
Place of ConferenceSuzhou
Country/Region of ConferenceChina
Year2018
Month11
LanguagesEnglish-United States

Last updated on 2018-07-11 at 17:02