Reduced levels of class 1 reversibly glycosylated polypeptide increase intercellular transport via plasmodesmata

Abstract

Maize and Arabidopsis thaliana class 1 reversibly glycosylated polypeptides ( C1 RGPs) are plasmodesmata-associated proteins. Previously, overexpression of Arabidopsis C1 RGP AtRGP2 in Nicotiana tabacum was shown to reduce intercellular transport of photoassimilate, resulting in stunted, chlorotic plants, and inhibition of local cell-to-cell spread of tobacco mosaic virus (TMV). Here, we used virus induced gene silencing to examine the effects of reduced levels of Plasmodesmata Structure and FunctionPlasmodesmata (PD) are membrane-lined cytoplasmic channels that connect contiguous plants cells, allowing transport of water, solutes, ions, nucleic acids and proteins between cells (for review see refs. 1-2). The importance of plasmodesmata to plant growth and development is demonstrated by the early lethality of mutants with altered PD structure and function.3,4 Electron microscopy reveals that PD consist largely of membranes and spaces (for review see ref. 5). Plasma membrane spans the cell wall between adjacent cells to form the outer limits of a given PD channel, and the ER of the adjacent two cells is continuous through the axial center of the channel, forming a specialized structure called the desmotubule (DT). Transport through PD is thought to predominantly occur in the space between the plasma membrane and DT, called the cytoplasmic sleeve, 6 while plant viruses also move along the membranes of the DT 7 and small molecules (~3 kDa) may move cell-to-cell via the lumen of the DT.

Gene Expression, Protein Function and Pathways of Arabidopsis thaliana Responding to Silver Nanoparticles in Comparison to Silver Ions, Cold, Salt, Drought, and Heat

“…First, a search was performed using “plasmodesmata” in the gene description and GO terms of AgNP and/or Ag + affected genes, which were obtained from BioMart [ 150 ]. Second, a list of genes that are directly related to plasmodesmata was prepared based on GO terms in AmiGO2 [ 146 , 151 , 152 , 153 , 154 ], GONUTS (the Gene Ontology Normal Usage Tracking System [ 155 ], and literature search [ 156 , 157 , 158 , 159 , 160 , 161 , 162 , 163 , 164 , 165 , 166 , 167 , 168 , 169 , 170 ]. Altogether, a list of the 26 plasmodesmata related genes was collected and it was provided in Table S13 .…”

Pontin/Reptin-associated complexes differentially impact plant development and viral pathology

“…One lower leaf per plant was syringe infiltrated with fresh overnight cultures of Agrobacterium resuspended in infiltration media (10 mM MgCl 2 , 10 mM MES, and 200 μM acetosyringone, pH 5.6) to a final OD 600nm = 0.5. Three Agrobacterium cultures were used that carried T-DNA encoding either TMV-GFP (Liu et al , 2002; Burch-Smith et al , 2012), PVX-GFP (Peart et al , 2002), or a mock control. All plants were photographed seven days post agroinfiltration under a long wave UV lamp (100 watt, 365 nm, 115V-60Hz).…”

Plasmodesmata Conductivity Regulation: A Mechanistic Model

“…Third, the deposition of calreticulin and reticulons in the DT lumen suggested by Knox et al leads to the expansion of the ER DT lumen [57]. Fourth, narrowing the Pd sleeves, as probably occurs through the participation of the actin-formin complex [70], as well as the accumulation of remorin [56], PDLP1 and 5 [75][76][77][78][79], GnTL [72], and C1 RGP [66][67][68]. Pd opening, as a process opposite to closing, can include (1) the removal of callose and (2) the displacement of negative regulators from the Pd structure.…”

“…Subsequently, this hypothesis was confirmed by experiments showing changes in the expression levels of the gene encoding At C1 RGP. It has been shown that At C1 RGP overexpression leads to a reduction in Pd permeability for photoassimilates and TMV cell-to-cell movement [68]; in contrast, reduced levels of At C1 RGP increase intercellular transport via Pd, and TMV exhibited accelerated systemic spread [66].…”