Cryo-electron tomography of the onion cell wall shows bimodally oriented cellulose fibers and reticulated homogalacturonan networks

Nicolas WJ, Fäßler F, Dutka P, Schur FK, Jensen G, Meyerowitz E. 2022. Cryo-electron tomography of the onion cell wall shows bimodally oriented cellulose fibers and reticulated homogalacturonan networks. Current Biology.

Download
OA 2022_CurrentBiology_Nicolas.pdf 12.71 MB

Journal Article | Epub ahead of print | English
Author
Nicolas, William J.; Fäßler, FlorianISTA ; Dutka, Przemysław; Schur, FlorianISTA ; Jensen, Grant; Meyerowitz, Elliot
Department
Abstract
One hallmark of plant cells is their cell wall. They protect cells against the environment and high turgor and mediate morphogenesis through the dynamics of their mechanical and chemical properties. The walls are a complex polysaccharidic structure. Although their biochemical composition is well known, how the different components organize in the volume of the cell wall and interact with each other is not well understood and yet is key to the wall’s mechanical properties. To investigate the ultrastructure of the plant cell wall, we imaged the walls of onion (Allium cepa) bulbs in a near-native state via cryo-focused ion beam milling (cryo-FIB milling) and cryo-electron tomography (cryo-ET). This allowed the high-resolution visualization of cellulose fibers in situ. We reveal the coexistence of dense fiber fields bathed in a reticulated matrix we termed “meshing,” which is more abundant at the inner surface of the cell wall. The fibers adopted a regular bimodal angular distribution at all depths in the cell wall and bundled according to their orientation, creating layers within the cell wall. Concomitantly, employing homogalacturonan (HG)-specific enzymatic digestion, we observed changes in the meshing, suggesting that it is—at least in part—composed of HG pectins. We propose the following model for the construction of the abaxial epidermal primary cell wall: the cell deposits successive layers of cellulose fibers at −45° and +45° relative to the cell’s long axis and secretes the surrounding HG-rich meshing proximal to the plasma membrane, which then migrates to more distal regions of the cell wall.
Publishing Year
Date Published
2022-05-03
Journal Title
Current Biology
Acknowledgement
This work was supported by the Howard Hughes Medical Institute (HHMI) and grant R35 GM122588 to G.J. and the Austrian Science Fund (FWF) P33367 to F.K.M.S. We thank Noé Cochetel for his guidance and great help in data analysis, discovery, and representation with the R software. We thank Hans-Ulrich Endress for graciously providing us with the purified citrus pectin and Jozef Mravec for generating and providing the COS488 probe. Cryo-EM work was done in the Beckman Institute Resource Center for Transmission Electron Microscopy at Caltech. This article is subject to HHMI’s Open Access to Publications policy. HHMI lab heads have previously granted a nonexclusive CC BY 4.0 license to the public and a sublicensable license to HHMI in their research articles. Pursuant to those licenses, the author accepted manuscript of this article can be made freely available under a CC BY 4.0 license immediately upon publication.
ISSN
IST-REx-ID

Cite this

Nicolas WJ, Fäßler F, Dutka P, Schur FK, Jensen G, Meyerowitz E. Cryo-electron tomography of the onion cell wall shows bimodally oriented cellulose fibers and reticulated homogalacturonan networks. Current Biology. 2022. doi:10.1016/j.cub.2022.04.024
Nicolas, W. J., Fäßler, F., Dutka, P., Schur, F. K., Jensen, G., & Meyerowitz, E. (2022). Cryo-electron tomography of the onion cell wall shows bimodally oriented cellulose fibers and reticulated homogalacturonan networks. Current Biology. Elsevier. https://doi.org/10.1016/j.cub.2022.04.024
Nicolas, William J., Florian Fäßler, Przemysław Dutka, Florian KM Schur, Grant Jensen, and Elliot Meyerowitz. “Cryo-Electron Tomography of the Onion Cell Wall Shows Bimodally Oriented Cellulose Fibers and Reticulated Homogalacturonan Networks.” Current Biology. Elsevier, 2022. https://doi.org/10.1016/j.cub.2022.04.024.
W. J. Nicolas, F. Fäßler, P. Dutka, F. K. Schur, G. Jensen, and E. Meyerowitz, “Cryo-electron tomography of the onion cell wall shows bimodally oriented cellulose fibers and reticulated homogalacturonan networks,” Current Biology. Elsevier, 2022.
Nicolas WJ, Fäßler F, Dutka P, Schur FK, Jensen G, Meyerowitz E. 2022. Cryo-electron tomography of the onion cell wall shows bimodally oriented cellulose fibers and reticulated homogalacturonan networks. Current Biology.
Nicolas, William J., et al. “Cryo-Electron Tomography of the Onion Cell Wall Shows Bimodally Oriented Cellulose Fibers and Reticulated Homogalacturonan Networks.” Current Biology, Elsevier, 2022, doi:10.1016/j.cub.2022.04.024.
All files available under the following license(s):
Copyright Statement:
This Item is protected by copyright and/or related rights. [...]
Main File(s)
Access Level
OA Open Access
Date Uploaded
2022-05-09
MD5 Checksum
7a7d38373074042c2fe5d027028bd0b7


Export

Marked Publications

Open Data ISTA Research Explorer

Search this title in

Google Scholar