Plant cell adhesion: A bioassay facilitates discovery of the first pectin biosynthetic gene

Lord, Elizabeth M.; Mollet, Jean‐Claude

doi:10.1073/pnas.012685099

Cited by 29 publications

(25 citation statements)

References 42 publications

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“…A slight reduction in the molar ratio of GalA to Rha was also observed in the total (enzymereleased) mucilage of atgatl5-1 (Table I), perhaps indicating a reduction in a HG component of the inner mucilage; no change in this ratio was observed in the outer (water-extractable) mucilage. Pectins are thought to act as adhesion molecules during plant growth, and several pectin mutants have been shown to have cell adhesion defects, including the qua1 mutant, which has been shown to have reduced HG biosynthesis activity (Willats et al, 2001c;Bouton et al, 2002;Iwai et al, 2002;Lord and Mollet, 2002;Orfila et al, 2005). The reduced cell adhesion found in atgatl5-1 seed coat epidermal cells is also consistent with the possible role of AtGATL5 in the synthesis of pectin.…”

Section: Discussionsupporting

confidence: 66%

GALACTURONOSYLTRANSFERASE-LIKE5 Is Involved in the Production of Arabidopsis Seed Coat Mucilage

et al. 2013

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The function of a putative galacturonosyltransferase from Arabidopsis (Arabidopsis thaliana; At1g02720; GALACTURONOSYLTRANSFERASE-LIKE5 [AtGATL5]) was studied using a combination of molecular genetic, chemical, and immunological approaches. AtGATL5 is expressed in all plant tissues, with highest expression levels in siliques 7 DPA. Furthermore, its expression is positively regulated by several transcription factors that are known to regulate seed coat mucilage production. AtGATL5 is localized in both endoplasmic reticulum and Golgi, in comparison with marker proteins resident to these subcellular compartments. A transfer DNA insertion in the AtGATL5 gene generates seed coat epidermal cell defects both in mucilage synthesis and cell adhesion. Transformation of atgatl5-1 mutants with the wild-type AtGATL5 gene results in the complementation of all morphological phenotypes. Compositional analyses of the mucilage isolated from the atgatl5-1 mutant demonstrated that galacturonic acid and rhamnose contents are decreased significantly in atgatl5-1 compared with wild-type mucilage. No changes in structure were observed between soluble mucilage isolated from wild-type and mutant seeds, except that the molecular weight of the mutant mucilage increased 63% compared with that of the wild type. These data provide evidence that AtGATL5 might function in the regulation of the final size of the mucilage rhamnogalacturonan I.

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Section: Discussionsupporting

confidence: 66%

GALACTURONOSYLTRANSFERASE-LIKE5 Is Involved in the Production of Arabidopsis Seed Coat Mucilage

et al. 2013

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“…Because pectin is known to underlie cell adhesion (Lord and Mollet, 2002), we investigated pectin content in the cell wall by staining for pectin, trying dyes including Ruthenium Red, Toluidine Blue and propidium iodide. However, the dyes stained wild-type plants inconsistently, limiting their usefulness.…”

Section: Rop Rnai Plants Have a Cell Adhesion Defectmentioning

confidence: 99%

A family of ROP proteins that suppress actin dynamics and are essential for polarized growth and cell adhesion

Burkart

Baskin

Bezanilla

2015

Journal of Cell Science

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In plants, the ROP family of small GTPases has been implicated in the polarized growth of tip-growing cells, such as root hairs and pollen tubes; however, most of the data derive from overexpressing ROP genes or constitutively active and dominant-negative isoforms, whereas confirmation by using loss-of-function studies has generally been lacking. Here, in the model moss Physcomitrella patens, we study ROP signaling during tip growth by using a loss-offunction approach based on RNA interference (RNAi) to silence the entire moss ROP family. We find that plants with reduced expression of ROP genes, in addition to failing to initiate tip growth, have perturbed cell wall staining, reduced cell adhesion and have increased actin-filament dynamics. Although plants subjected to RNAi against the ROP family also have reduced microtubule dynamics, this reduction is not specific to loss of ROP genes, as it occurs when actin function is compromised chemically or genetically. Our data suggest that ROP proteins polarize the actin cytoskeleton by suppressing actin-filament dynamics, leading to an increase in actin filaments at the site of polarized secretion.

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“…Pectins, particularly homogalacturonan (HG) with a low degree of methylesterification (DM), are also abundant in the middle lamella, where they mediate cell-cell adhesion (Lord and Mollet, 2002;Wolf et al, 2009a). HG consists of unbranched chains of (1→4)-a-Dgalacturonic acid (GalA), and rhamnogalacturonan-II has the same backbone but is a highly substituted polymer.…”

Section: Introductionmentioning

confidence: 99%

FLYING SAUCER1 Is a Transmembrane RING E3 Ubiquitin Ligase That Regulates the Degree of Pectin Methylesterification inArabidopsisSeed Mucilage

et al. 2013

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Pectins are complex polysaccharides that form the gel matrix of the primary cell wall and are abundant in the middle lamella that holds plant cells together. Their degree of methylesterification (DM) impacts wall strength and cell adhesion since unesterified pectin regions can cross-link via Ca 2+ ions to form stronger gels. Here, we characterize flying saucer1 (fly1), a novel Arabidopsis thaliana seed coat mutant, which displays primary wall detachment, reduced mucilage extrusion, and increased mucilage adherence. These defects appear to result from a lower DM in mucilage and are enhanced by the addition of Ca 2+ or completely rescued using alkaline Ca 2+ chelators. FLY1 encodes a transmembrane protein with a RING-H2 domain that has in vitro E3 ubiquitin ligase activity. FLY1 is orthologous to TRANSMEMBRANE UBIQUITIN LIGASE1, a Golgi-localized E3 ligase involved in the quality control of membrane proteins in yeast. However, FLY1-yellow fluorescent protein (YFP) fusions are localized in punctae that are predominantly distinct from the Golgi and the trans-Golgi network/early endosome in the seed coat epidermis. Wortmannin treatment, which induces the fusion of late endosomes in plants, resulted in enlarged FLY1-YFP bodies. We propose that FLY1 regulates the DM of pectin in mucilage, potentially by recycling pectin methylesterase enzymes in the endomembrane system of seed coat epidermal cells.

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Plant cell adhesion: A bioassay facilitates discovery of the first pectin biosynthetic gene

Cited by 29 publications

References 42 publications

GALACTURONOSYLTRANSFERASE-LIKE5 Is Involved in the Production of Arabidopsis Seed Coat Mucilage

GALACTURONOSYLTRANSFERASE-LIKE5 Is Involved in the Production of Arabidopsis Seed Coat Mucilage

A family of ROP proteins that suppress actin dynamics and are essential for polarized growth and cell adhesion

FLYING SAUCER1 Is a Transmembrane RING E3 Ubiquitin Ligase That Regulates the Degree of Pectin Methylesterification inArabidopsisSeed Mucilage

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