Primary and secondary plasmodesmata: structure, origin, and functioning

PROTOPLASMA ◽  
2001 ◽  
Vol 216 (1-2) ◽  
pp. 1-30 ◽  
Author(s):  
K. Ehlers ◽  
R. Kollmann
Keyword(s):  
Secondary Plasmodesmata

PIT MEMBRANES OF EPHEDRA RESEMBLE GYMNOSPERMS MORE THAN ANGIOSPERMS

IAWA Journal ◽  
2014 ◽  
Vol 35 (3) ◽  
pp. 217-235 ◽  
Author(s):  
Roland R. Dute ◽  
Lauren A. Bowen ◽  
Sarah Schier ◽  
Alexa G. Vevon ◽  
Troy L. Best ◽  
...  
Keyword(s):  
Bordered Pit ◽  
Pit Membrane ◽  
Torus Surface ◽  
Different Types ◽  
Secondary Plasmodesmata ◽  
Ultrathin Sections

Bordered pit pairs of Ephedra species were characterized using different types of microscopy. Pit membranes contained tori that did not stain for lignin. SEM and AFM views of the torus surface showed no plasmodesmatal openings, but branched, secondary plasmodesmata were occasionally noted using TEM in conjunction with ultrathin sections. The margo consisted of radial microfibrils as well as finer diameter tangential fibrils. The former formed fascicles of fibrils that merged into even thicker buttresses during the act of pit membrane aspiration. AFM showed a discontinuous layer of non-microfibrillar material on the surface of both torus and margo. It is hypothesized that this material is responsible for adhesion of the pit membrane to the surface of the pit border during the process of aspiration. Taken as a whole, intervascular pit membranes of Ephedra more closely resemble those of conifers than those of torus-bearing pit membranes of angiosperms.

scholarly journals A CLEM approach to access to the ultrastructure at the graft interface in Arabidopsis thaliana

2021 ◽  
Author(s):  
Clément Chambaud ◽  
Sarah Jane Cookson ◽  
Nathalie Ollat ◽  
Emmanuelle M. F. Bayer ◽  
Lysiane Brocard
Keyword(s):  
Electron Microscopy ◽  
Arabidopsis Thaliana ◽  
Endoplasmic Reticulum ◽  
Cell Wall ◽  
Light And Electron Microscopy ◽  
Three Dimensional ◽  
Cellular Events ◽  
Membrane Tethering ◽  
Secondary Plasmodesmata ◽  
Graft Interface

Despite recent progress in our understanding of the graft union formation, we still know little about the cellular events underlying the grafting process. This is partially due to the difficulty of reliably targeting the graft interface in electron microscopy to study its ultrastructure and three-dimensional architecture. To overcome this technological bottleneck, we developed a correlative light electron microscopy approach (CLEM) to study the graft interface with high ultrastructural resolution. Grafting hypocotyls of Arabidopsis thaliana lines expressing YFP or mRFP in the endoplasmic reticulum allowed the efficient targeting of the grafting interface for under light and electron microscopy. To explore the potential of our method to study sub-cellular events at the graft interface, we focused on the formation of secondary plasmodesmata (PD) between the grafted partners. We showed that 4 classes of PD were formed at the interface and that PD introgression into the call wall was initiated equally by both partners. Moreover, the success of PD formation appeared not systematic with a third of PD not spanning the cell wall entirely. Characterizing the ultrastructural characteristics of these failed PD gives us insights into the process of secondary PD biogenesis. We showed that the thinning of the cell wall and the endoplasmic reticulum-plasma membrane tethering seem to be required for the establishment of symplastic connections between the scion and the rootstock. The resolution reached in this work shows that our CLEM method offer a new scale to the study for biological processes requiring the combination of light and electron microscopy.

scholarly journals The Enigma of Interspecific Plasmodesmata: Insight From Parasitic Plants

2021 ◽  
Vol 12 ◽  
Author(s):  
Karsten Fischer ◽  
Lena Anna-Maria Lachner ◽  
Stian Olsen ◽  
Maria Mulisch ◽  
Kirsten Krause
Keyword(s):  
Host Plants ◽  
Large Range ◽  
Parasitic Plants ◽  
Individual Plant ◽  
Host System ◽  
Molecular Approaches ◽  
Open Questions ◽  
Technical Advances ◽  
Secondary Plasmodesmata ◽  
Insight Into

Parasitic plants live in intimate physical connection with other plants serving as their hosts. These host plants provide the inorganic and organic compounds that the parasites need for their propagation. The uptake of the macromolecular compounds happens through symplasmic connections in the form of plasmodesmata. In contrast to regular plasmodesmata, which connect genetically identical cells of an individual plant, the plasmodesmata that connect the cells of host and parasite join separate individuals belonging to different species and are therefore termed “interspecific”. The existence of such interspecific plasmodesmata was deduced either indirectly using molecular approaches or observed directly by ultrastructural analyses. Most of this evidence concerns shoot parasitic Cuscuta species and root parasitic Orobanchaceae, which can both infect a large range of phylogenetically distant hosts. The existence of an interspecific chimeric symplast is both striking and unique and, with exceptions being observed in closely related grafted plants, exist only in these parasitic relationships. Considering the recent technical advances and upcoming tools for analyzing parasitic plants, interspecific plasmodesmata in parasite/host connections are a promising system for studying secondary plasmodesmata. For open questions like how their formation is induced, how their positioning is controlled and if they are initiated by one or both bordering cells simultaneously, the parasite/host interface with two adjacent distinguishable genetic systems provides valuable advantages. We summarize here what is known about interspecific plasmodesmata between parasitic plants and their hosts and discuss the potential of the intriguing parasite/host system for deepening our insight into plasmodesmatal structure, function, and development.

Secondary Plasmodesmata Are Specific Sites of Localization of the Tobacco Mosaic Virus Movement Protein in Transgenic Tobacco Plants

1992 ◽  
Vol 4 (8) ◽  
pp. 915 ◽  
Author(s):  
Biao Ding ◽  
James S. Haudenshield ◽  
Richard J. Hull ◽  
Shmuel Wolf ◽  
Roger N. Beachy ◽  
...  
Keyword(s):  
Tobacco Mosaic Virus ◽  
Mosaic Virus ◽  
Transgenic Tobacco ◽  
Movement Protein ◽  
Virus Movement ◽  
Transgenic Tobacco Plants ◽  
Tobacco Plants ◽  
Secondary Plasmodesmata
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