scholarly journals Unraveling the puzzle of phloem parenchyma transfer cell wall ingrowth

2020 ◽  
Vol 71 (16) ◽  
pp. 4617-4620 ◽  
Author(s):  
Tyler J McCubbin ◽  
David M Braun
Keyword(s):  
Cell Wall ◽  
Phloem Loading ◽  
Transfer Cells ◽  
Transfer Cell ◽  
Phloem Parenchyma ◽  
Wall Ingrowth ◽  
Experimental Botany

This article comments on: Wei X, Nguyen ST, Collings DA, McCurdy DW. 2020. Sucrose regulates wall ingrowth deposition in phloem parenchyma transfer cells in Arabidopsis via affecting phloem loading activity. Journal of Experimental Botany 71, 4690–4702.

scholarly journals Sucrose regulates wall ingrowth deposition in phloem parenchyma transfer cells in Arabidopsis via affecting phloem loading activity

2020 ◽  
Vol 71 (16) ◽  
pp. 4690-4702 ◽  
Author(s):  
Xiaoyang Wei ◽  
Suong T T Nguyen ◽  
David A Collings ◽  
David W McCurdy
Keyword(s):  
Expression Analysis ◽  
Gene Expression Analysis ◽  
Phloem Loading ◽  
Transfer Cells ◽  
Null Mutant ◽  
Dark Treatment ◽  
Phloem Parenchyma ◽  
Wall Ingrowth ◽  
Overexpression Line ◽  
Regulated Expression

Abstract In Arabidopsis thaliana, phloem parenchyma transfer cells (PPTCs) occur in leaf minor veins and play a pivotal role in phloem loading. Wall ingrowth formation in PPTCs is induced by the phloem loading activity of these cells, which is regulated by sucrose (Suc). The effects of endogenous versus exogenous Suc on wall ingrowth deposition, however, differ. Elevating endogenous Suc levels by increased light enhanced wall ingrowth formation, whereas lowering endogenous Suc levels by dark treatment or genetically in ch-1 resulted in lower levels of deposition. In contrast, exogenously applied Suc, or Suc derived from other organs, repressed wall ingrowth deposition. Analysis of pAtSUC2::GFP plants, used as a marker for phloem loading status, suggested that wall ingrowth formation is correlated with phloem loading activity. Gene expression analysis revealed that exogenous Suc down-regulated expression of AtSWEET11 and 12, whereas endogenous Suc up-regulated AtSWEET11 expression. Analysis of a TREHALOSE 6-PHOSPHATE (T6P) SYNTHASE overexpression line and the hexokinase (HXK)-null mutant, gin2-1, suggested that Suc signalling of wall ingrowth formation is independent of T6P and HXK. Collectively, these results are consistent with the conclusion that Suc regulates wall ingrowth formation via affecting Suc exporting activity in PPTCs.

scholarly journals Asymmetric wall ingrowth deposition in Arabidopsis phloem parenchyma transfer cells is tightly associated with sieve elements

2022 ◽  
Author(s):  
Xiaoyang Wei ◽  
Yuan Huang ◽  
David A Collings ◽  
David W McCurdy
Keyword(s):  
Cell Types ◽  
Phloem Loading ◽  
Transfer Cells ◽  
Companion Cell ◽  
Wall Ingrowths ◽  
Phloem Parenchyma ◽  
Wall Ingrowth ◽  
Functional Differences ◽  
Transgenic Lines ◽  
Different Cell Types

In Arabidopsis, polarized deposition of wall ingrowths in phloem parenchyma (PP) transfer cells (TCs) occurs adjacent to cells of the sieve element/companion cell (SE/CC) complex. However, the spatial relationships between these different cell types in minor veins, where phloem loading occurs, are poorly understood. PP TC development and wall ingrowth localization were compared to other phloem cells in leaves of Col-0 and the transgenic lines AtSUC2::AtSTP9-GFP and AtSWEET11::AtSWEET11-GFP that identify CCs and PP respectively. The development of PP TCs in minor veins, indicated by deposition of wall ingrowths, proceeded basipetally in leaves. However, not all PP develop ingrowths and higher levels of wall ingrowth deposition occur in abaxial- compared to adaxial-positioned PP TCs. Furthermore, the deposition of wall ingrowths was exclusively initiated on and preferentially covered the PP TC/SE interface, rather than the PP TC/CC interface, and only occurred in PP cells that were adjacent to SEs. Collectively, these results demonstrate the dominant impact of SEs on wall ingrowth deposition in PP TCs and suggest the existence of two sub-types of PP cells in leaf minor veins. Compared to PP cells, PP TCs showed more abundant accumulation of AtSWEET11-GFP, indicating functional differences in phloem loading between PP and PP TCs.

A light and electron microscope investigation of the transfer cell region of maize caryopses

1990 ◽  
Vol 68 (3) ◽  
pp. 471-479 ◽  
Author(s):  
Ronald W. Davis ◽  
J. D. Smith ◽  
B. Greg Cobb
Keyword(s):  
Cell Wall ◽  
Cross Section ◽  
Close Association ◽  
Transfer Cells ◽  
Transfer Cell ◽  
Cell Region ◽  
Maternal Tissue ◽  
X Ray ◽  
Numerous Cell ◽  
Electron Microscopes

The transfer cell zones from 23-day postpollination corn caryopses were examined using light and electron microscopes and X-ray elemental analysis. The transfer cells were sectioned in cross and longitudinal planes and were characterized by having numerous cell-wall extensions in the form of anastomosing lamellae. The most basal transfer cells had more cell-wall extensions than those that were successively deeper in the endosperm. Cytoplasm, rich with mitochondria, filled the interstices of cell-wall extensions, and many vesiculate areas could be found along the plasma membrane. Some transfer cells contained crystals within plastids. The crystals were composed of magnesium, phosphorus, calcium, and zinc. Other cells had large aggregations of endoplasmic reticulum that were often in close association with mitochondria or unidentified, single membrane bounded organelles. When viewed in cross section, the cell-wall extensions of contiguous cells tended to originate from common loci. Plasmodesmata were absent in the bottom parts of the basal transfer cells where they contacted the maternal tissue but were abundant in the upper parts of these cells and in the transfer cells found deeper in the endosperm. The plasmodesmata were found in clusters and alternated with the wall extension areas.

scholarly journals GIGANTEA is a component of a regulatory pathway determining wall ingrowth deposition in phloem parenchyma transfer cells of Arabidopsis thaliana

2010 ◽  
Vol 63 (4) ◽  
pp. 651-661 ◽  
Author(s):  
Joshua Edwards ◽  
Antony P. Martin ◽  
Felicity Andriunas ◽  
Christina E. Offler ◽  
John W. Patrick ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Transfer Cells ◽  
Regulatory Pathway ◽  
Phloem Parenchyma ◽  
Wall Ingrowth

scholarly journals The Placenta of Physcomitrium patens: Transfer Cell Wall Polymers Compared across the Three Bryophyte Groups

Diversity ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 378
Author(s):  
Jason S. Henry ◽  
Karen S. Renzaglia
Keyword(s):  
Cell Wall ◽  
Cell Walls ◽  
Cell Wall Composition ◽  
Transfer Cells ◽  
Primary Cell ◽  
Transfer Cell ◽  
Primary Cell Wall ◽  
Slight Variation ◽  
Wall Ingrowths ◽  
Cell Wall Polymers

Following similar studies of cell wall constituents in the placenta of Phaeoceros and Marchantia, we conducted immunogold labeling TEM studies of Physcomitrium patens to determine the composition of cell wall polymers in transfer cells on both sides of the placenta. Sixteen monoclonal antibodies were used to localize cell wall epitopes in the basal walls and wall ingrowths in this moss. In general, placental transfer cell walls of P. patens contained fewer pectins and far fewer arabinogalactan proteins AGPs than those of the hornwort and liverwort. P. patens also lacked the differential labeling that is pronounced between generations in the other bryophytes. In contrast, transfer cell walls on either side of the placenta of P. patens were relatively similar in composition, with slight variation in homogalacturonan HG pectins. Compositional similarities between wall ingrowths and primary cell walls in P. patens suggest that wall ingrowths may simply be extensions of the primary cell wall. Considerable variability in occurrence, abundance, and types of polymers among the three bryophytes and between the two generations suggested that similarity in function and morphology of cell walls does not require a common cell wall composition. We propose that the specific developmental and life history traits of these plants may provide even more important clues in understanding the basis for these differences. This study significantly builds on our knowledge of cell wall composition in bryophytes in general and in transfer cells across plants.

scholarly journals Plastids features and transfer cells occurrence in the phloem of Portulaca mucronata and P. hirsutissima (Portulacaceae)

2014 ◽  
Vol 64 (2) ◽  
pp. 149-153 ◽  
Author(s):  
Maria E. Maranhão Estelita ◽  
Tereza C. Marinho
Keyword(s):  
Cell Wall ◽  
Secondary Cell Wall ◽  
Transfer Cells ◽  
Leaf Structure ◽  
Primary Cell Wall ◽  
Starch Grains ◽  
Kranz Anatomy ◽  
Phloem Parenchyma ◽  
Serra Do Cipó ◽  
Parenchyma Cells

The species of the <em>Portulacaceae</em> of the Serra do Cipó, State of Minas Gerais, Brasil, were studied. In <em>Portulaca mucronata</em> and <em>P. hirsutissima</em> transfer cells are companion and phloem parenchyma cells; they have the same secondary cell wall features, that is, short papillate protuberances which are uniformly distributed around the primary cell wall. These features are similar in both species but they are very distinct from others referred in the literature; this could be useful in Taxonomy. The phloem plastids have a globular protein crystalloid, surrounded by proteinaceous filaments. In <em>P. hirsutissima</em> few starch grains may also be present, and this occurrence is considered primitive in the phylogenetic scale. These features agree with presumptive evolution of those of leaf structure: <em>P. hirsutissima</em> has C<sub>3</sub> photosynthesis structure, and <em>P. mucronata</em> C<sub>4</sub> or Kranz anatomy.

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