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.

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.

Ontogeny of phloem transfer cells in Hieracium floribundum

1975 ◽  
Vol 53 (23) ◽  
pp. 2745-2758 ◽  
Author(s):  
R. L. Peterson ◽  
E. C. Yeung
Keyword(s):  
Cell Types ◽  
Transfer Cells ◽  
Vascular Cambium ◽  
Secondary Phloem ◽  
Sieve Elements ◽  
Wall Ingrowths ◽  
Wall Ingrowth ◽  
Companion Cells ◽  
Parenchyma Cells ◽  
Cambium Activity

The primary phloem system in the rhizome of Hieracium floribundum has transfer cells that have developed from companion cells and parenchyma cells, which are adjacent to sieve elements. In both cell types changes occur in the cytoplasmic organelles at the time of wall ingrowth formation. Dicytosomes and polyribosomes become more numerous and 'boundary formations' and other multivesiculated structures appear. Few microtubules were found in the cytoplasm at this time. After the wall ingrowths become obvious, the transfer cells develop numerous mitochondria and an enlarged nucleus. The phloem transfer cells become vacuolated with age and the wall ingrowths become less numerous. This may be associated with a change in the translocation pattern in the phloem after the inception of vascular cambium activity. Parenchyma cells in the secondary phloem usually become rather vacuolated and develop few wall ingrowths.

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 Mapping Pectic-Polysaccharide Epitopes in Cell Walls of Forage Chicory (Cichorium intybus) Leaves

2021 ◽  
Vol 12 ◽  
Author(s):  
Xuezhao Sun ◽  
Ian G. Andrew ◽  
Philip J. Harris ◽  
Simone O. Hoskin ◽  
Keith N. Joblin ◽  
...  
Keyword(s):  
Cell Walls ◽  
Middle Lamella ◽  
Cell Types ◽  
Cichorium Intybus ◽  
Vascular Bundles ◽  
Differential Distribution ◽  
Pectic Polysaccharides ◽  
Pectic Polysaccharide ◽  
Phloem Parenchyma ◽  
Different Cell Types

The cell walls of forage chicory (Cichorium intybus) leaves are known to contain high proportions of pectic polysaccharides. However, little is known about the distribution of pectic polysaacharides among walls of different cell types/tissues and within walls. In this study, immunolabelling with four monoclonal antibodies was used to map the distribution of pectic polysaccharides in the cell walls of the laminae and midribs of these leaves. The antibodies JIM5 and JIM7 are specific for partially methyl-esterified homogalacturonans; LM5 and LM6 are specific for (1→4)-β-galactan and (1→5)-α-arabinan side chains, respectively, of rhamnogalacturonan I. All four antibodies labelled the walls of the epidermal cells with different intensities. JIM5 and JIM7, but not LM5 or LM6, labelled the middle lamella, tricellular junctions, and the corners of intercellular spaces of ground, xylem and phloem parenchyma. LM5, but not LM6, strongly labelled the walls of the few sclerenchyma fibres in the phloem of the midrib and lamina vascular bundles. The LM5 epitope was absent from some phloem parenchyma cells. LM6, but not LM5, strongly labelled the walls of the stomatal guard cells. The differential distribution of pectic epitopes among walls of different cell types and within walls may reflect the deposition and modification of these polysaccharides which are involved in cell wall properties and cell development.

Ultrastructural features of the gut of Sitophilus granarius (L.) (Coleoptera: Curculionidae) with notes on distribution of proteinases and amylases in crop and midgut

1984 ◽  
Vol 62 (7) ◽  
pp. 1251-1259 ◽  
Author(s):  
J. E. Baker ◽  
S. M. Woo ◽  
R. V. Byrd
Keyword(s):  
Plasma Membranes ◽  
Cell Types ◽  
Sitophilus Granarius ◽  
Posterior Midgut ◽  
Functional Differences ◽  
Basal Plasma ◽  
Dark Staining ◽  
Different Cell Types ◽  
Columnar Cells ◽  
Anterior Midgut

In addition to typical columnar cells, dark-staining cells characterized by deep invaginations of basal plasma membranes were found throughout the midgut of adult Sitophilus granarius (L.). These invaginations formed intracellular channels that extended to the perinuclear region and indicated an involvement of these cells in secretion and (or) absorption. Cells with large vacuolelike structures that occasionally filled the entire supranuclear region were found in the anterior midgut, while multicellular crypts and cells that formed apical extrusions into the lumen were common in the posterior midgut. Fine structure of gastric caeca indicated functional differences between those located in anterior and posterior midgut regions. Numerous dark-staining granules were found in apical regions of cells of the anterior caeca, whereas elongated mitochondria were found in microvilli that made up the brush border of posterior caecal cells. Thus, although the midgut is not obviously differentiated into zones, there are different cell types in different regions of the gut involved in digestive and nutrient absorption processes. Evidence indicated that amylase in S. granarius is secreted by salivary glands whereas trypsin and aminopeptidase are secreted by midgut. A slow, continuous secretion of amylase occurs whereas proteinases are secreted in response to ingested food.

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