scholarly journals Arabidopsis O-fucosyltransferase SPINDLY regulates root hair patterning independently of gibberellin signalling

2020 ◽  
Author(s):  
Krishna Vasant Mutanwad ◽  
Isabella Zangl ◽  
Doris Lucyshyn
Keyword(s):  
Cell Fate ◽  
Root Hair ◽  
Environmental Changes ◽  
Root Hairs ◽  
Specific Pattern ◽  
Loss Of Function ◽  
Soil Composition ◽  
Post Translational Modification ◽  
Internal Factors ◽  
Root Hair Cells

AbstractRoot hairs are able to sense soil composition and play an important role for water and nutrient uptake. In Arabidopsis thaliana, root hairs are distributed in the epidermis in a specific pattern, regularly alternating with non-root hair cells in continuous cell files. This patterning is regulated by internal factors such as a number of hormones, as well as external factors like nutrient availability. Thus, root-hair patterning is an excellent model for studying the plasticity of cell fate determination in response to environmental changes. Here, we report that loss-of-function mutants in the Protein O-Fucosyltransferase SPINDLY (SPY) form ectopic root hairs. Using a number of transcriptional reporters, we show that patterning in spy-22 is affected upstream of the central regulators GLABRA2 (GL2) and WEREWOLF (WER). O-fucosylation of nuclear and cytosolic proteins is an important post-translational modification that is still not very well understood. So far, SPY is best characterized for its role in gibberellin signalling via fucosylation of the growth-repressing DELLA protein REPRESSOR OF GA (RGA). Our data suggest that the formation of ectopic root hairs in spy-22 is independent of RGA and gibberellin signalling.

scholarly journals The Arabidopsis O-fucosyltransferase SPINDLY regulates root hair patterning independently of gibberellin signaling

Development ◽  
2020 ◽  
Vol 147 (19) ◽  
pp. dev192039
Author(s):  
Krishna Vasant Mutanwad ◽  
Isabella Zangl ◽  
Doris Lucyshyn
Keyword(s):  
Cell Fate ◽  
Root Hair ◽  
Environmental Changes ◽  
Root Hairs ◽  
Specific Pattern ◽  
Loss Of Function ◽  
Soil Composition ◽  
Post Translational Modification ◽  
Internal Factors ◽  
Gibberellin Signaling

ABSTRACTRoot hairs are able to sense soil composition and play an important role in water and nutrient uptake. In Arabidopsis thaliana, root hairs are distributed in the epidermis in a specific pattern, regularly alternating with non-root hair cells in continuous cell files. This patterning is regulated by internal factors such as a number of hormones, as well as by external factors like nutrient availability. Thus, root hair patterning is an excellent model for studying the plasticity of cell fate determination in response to environmental changes. Here, we report that loss-of-function mutants for the Protein O-fucosyltransferase SPINDLY (SPY) show defects in root hair patterning. Using transcriptional reporters, we show that patterning in spy-22 is affected upstream of GLABRA2 (GL2) and WEREWOLF (WER). O-fucosylation of nuclear and cytosolic proteins is an important post-translational modification that is still not very well understood. So far, SPY is best characterized for its role in gibberellin signaling via fucosylation of the growth-repressing DELLA protein REPRESSOR OF ga1-3 (RGA). Our data suggest that the epidermal patterning defects in spy-22 are independent of RGA and gibberellin signaling.

scholarly journals The TOR–Auxin Connection Upstream of Root Hair Growth

Plants ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 150 ◽  
Author(s):  
Katarzyna Retzer ◽  
Wolfram Weckwerth
Keyword(s):  
Cell Fate ◽  
Root Hair ◽  
Hair Growth ◽  
Environmental Changes ◽  
Growth Control ◽  
Root Hairs ◽  
Signaling Cascades ◽  
Continuous Growth ◽  
Root Hair Cell ◽  
Root Hair Growth

Plant growth and productivity are orchestrated by a network of signaling cascades involved in balancing responses to perceived environmental changes with resource availability. Vascular plants are divided into the shoot, an aboveground organ where sugar is synthesized, and the underground located root. Continuous growth requires the generation of energy in the form of carbohydrates in the leaves upon photosynthesis and uptake of nutrients and water through root hairs. Root hair outgrowth depends on the overall condition of the plant and its energy level must be high enough to maintain root growth. TARGET OF RAPAMYCIN (TOR)-mediated signaling cascades serve as a hub to evaluate which resources are needed to respond to external stimuli and which are available to maintain proper plant adaptation. Root hair growth further requires appropriate distribution of the phytohormone auxin, which primes root hair cell fate and triggers root hair elongation. Auxin is transported in an active, directed manner by a plasma membrane located carrier. The auxin efflux carrier PIN-FORMED 2 is necessary to transport auxin to root hair cells, followed by subcellular rearrangements involved in root hair outgrowth. This review presents an overview of events upstream and downstream of PIN2 action, which are involved in root hair growth control.

scholarly journals A role for the RabA4b effector protein PI-4Kβ1 in polarized expansion of root hair cells in Arabidopsis thaliana

2006 ◽  
Vol 172 (7) ◽  
pp. 991-998 ◽  
Author(s):  
Mary L. Preuss ◽  
Aaron J. Schmitz ◽  
Julie M. Thole ◽  
Heather K.S. Bonner ◽  
Marisa S. Otegui ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Hair Cells ◽  
Root Hair ◽  
Root Hairs ◽  
Developmentally Regulated ◽  
Domain Specific ◽  
Polarized Secretion ◽  
Phosphatidylinositol 4 ◽  
Golgi Network ◽  
Root Hair Cells

The RabA4b GTPase labels a novel, trans-Golgi network compartment displaying a developmentally regulated polar distribution in growing Arabidopsis thaliana root hair cells. GTP bound RabA4b selectively recruits the plant phosphatidylinositol 4-OH kinase, PI-4Kβ1, but not members of other PI-4K families. PI-4Kβ1 colocalizes with RabA4b on tip-localized membranes in growing root hairs, and mutant plants in which both the PI-4Kβ1 and -4Kβ2 genes are disrupted display aberrant root hair morphologies. PI-4Kβ1 interacts with RabA4b through a novel homology domain, specific to eukaryotic type IIIβ PI-4Ks, and PI-4Kβ1 also interacts with a Ca2+ sensor, AtCBL1, through its NH2 terminus. We propose that RabA4b recruitment of PI-4Kβ1 results in Ca2+-dependent generation of PI-4P on this compartment, providing a link between Ca2+ and PI-4,5P2–dependent signals during the polarized secretion of cell wall components in tip-growing root hair cells.

scholarly journals AtRBOHC/RHD2 vesicular delivery to the apical plasma membrane domain during root hair development

2021 ◽  
Author(s):  
Lenka Kuběnová ◽  
Michaela Tichá ◽  
Jozef Šamaj ◽  
Miroslav Ovečka
Keyword(s):  
Plasma Membrane ◽  
Quantitative Analysis ◽  
Root Hair ◽  
Tip Growth ◽  
Root Hairs ◽  
Apical Plasma Membrane ◽  
Loss Of Function ◽  
Short Root ◽  
Early Endosomes ◽  
Root Hair Initiation

AbstractArabidopsis root hairs develop as long tubular extensions from the rootward pole of trichoblasts and exert polarized tip growth. The establishment and maintenance of root hair polarity is a complex process involving the local apical production of reactive oxygen species (ROS) generated by NADPH oxidase RESPIRATORY BURST OXIDASE HOMOLOG PROTEIN C/ROOT HAIR DEFECTIVE 2 (AtRBOHC/RHD2). It has been shown that loss-of-function rhd2 mutants have short root hairs that are unable to elongate by tip growth, and this phenotype was fully complemented by GFP-RHD2 expressed under the RHD2 promoter. However, the spatiotemporal mechanism of AtRBOHC/RHD2 subcellular redistribution and delivery to the plasma membrane (PM) during root hair initiation and tip growth are still unclear. Here, we used advanced microscopy for detailed qualitative and quantitative analysis of vesicular compartments containing GFP-RHD2 and characterization of their movements in developing bulges and growing root hairs. These compartments, identified by an independent marker such as the trans-Golgi network (TGN), deliver GFP-RHD2 to the apical PM domain, the extent of which correlates with the stage of root hair formation. Movements of TGN/early endosomes, but not late endosomes, were affected in the bulging domains of the rhd2-1 mutant. Finally, we reveal that accumulation in the growing tip, docking, and incorporation of TGN compartments containing GFP-RHD2 to the apical PM of root hairs requires structural sterols. These results help clarify the mechanism of polarized AtRBOHC/RHD2 targeting, maintenance, and recycling at the apical PM domain, coordinated with different developmental stages of root hair initiation and growth.One-sentence summaryAdvanced microscopy and quantitative analysis of vesicular TGN compartments revealed that delivering GFP-RHD2 to the apical plasma membrane domains of developing bulges and growing root hairs requires structural sterols.

scholarly journals Supra-physiological levels of Gibberellins/DELLAs alter the patterning, morphology and abundance of root hairs in root tips of A. thaliana seedlings

2021 ◽  
Author(s):  
Iva McCarthy-Suarez
Keyword(s):  
Gene Expression ◽  
Cell Fate ◽  
Epidermal Cell ◽  
Root Hair ◽  
Root Hairs ◽  
Root Tip ◽  
Spatial Patterning ◽  
Root Tips ◽  
Root Epidermis

In spite of the known role of gibberellins (GAs), and of their antagonistic proteins, the DELLAs, in leaf hair production, no investigations, however, have assessed their hypothetical function in the production of root hairs. To this aim, the effects of supra-physiological levels of GAs/DELLAs on the spatial patterning of gene expression of the root hair (CPC) and root non-hair (GL2, EGL3 and WER) epidermal cell fate markers, as well as on the distribution, morphology and abundance of root hairs, were studied in root tips of 5-day-old A. thaliana seedlings. Results showed that excessive levels of GAs/DELLAs impaired the spatial patterning of gene expression of the root hair/non-hair epidermal cell fate markers, as well as the arrangement, shape and frequency of root hairs, giving rise to ectopic hairs and ectopic non-hairs, two-haired cells, two-tipped hairs, branched hairs, longer and denser hairs near the root tip under excessive DELLAs, and shorter and scarcer hairs near the root tip under excessive GAs. However, when the gai-1 (GA-insensitive-1) DELLA mutant protein was specifically over-expressed at the root epidermis, no changes in the patterning or abundance of root hairs occurred. Thus, these results suggest that, in seedlings of A. thaliana, the GAs/DELLAs might have a role in regulating the patterning, morphology and abundance of root hairs by acting from the sub-epidermal tissues of the root.

The homeobox gene GLABRA2 is required for position-dependent cell differentiation in the root epidermis of Arabidopsis thaliana

Development ◽  
1996 ◽  
Vol 122 (4) ◽  
pp. 1253-1260 ◽  
Author(s):  
J.D. Masucci ◽  
W.G. Rerie ◽  
D.R. Foreman ◽  
M. Zhang ◽  
M.E. Galway ◽  
...  
Keyword(s):  
Epidermal Cell ◽  
Hair Cells ◽  
Root Hair ◽  
Root Hairs ◽  
Homeobox Gene ◽  
Epidermal Cells ◽  
Wild Type ◽  
Cell Identity ◽  
Root Epidermis ◽  
Root Hair Cells

The role of the Arabidopsis homeobox gene, GLABRA 2 (GL2), in the development of the root epidermis has been investigated. The wild-type epidermis is composed of two cell types, root-hair cells and hairless cells, which are located at distinct positions within the root, implying that positional cues control cell-type differentiation. During the development of the root epidermis, the differentiating root-hair cells (trichoblasts) and the differentiating hairless cells (atrichoblasts) can be distinguished by their cytoplasmic density, vacuole formation, and extent of elongation. We have determined that mutations in the GL2 gene specifically alter the differentiation of the hairless epidermal cells, causing them to produce root hairs, which indicates that GL2 affects epidermal cell identity. Detailed analyses of these differentiating cells showed that, despite forming root hairs, they are similar to atrichoblasts of the wild type in their cytoplasmic characteristics, timing of vacuolation, and extent of cell elongation. The results of in situ nucleic acid hybridization and GUS reporter gene fusion studies show that the GL2 gene is preferentially expressed in the differentiating hairless cells of the wild type, during a period in which epidermal cell identity is believed to be established. These results indicate that the GL2 homeodomain protein normally regulates a subset of the processes that occur during the differentiation of hairless epidermal cells of the Arabidopsis root. Specifically, GL2 appears to act in a cell-position-dependent manner to suppress hair formation in differentiating hairless cells.

scholarly journals New insights on the role of HCN in root hair elongation through single cell proteomics

2022 ◽  
Author(s):  
Irene García ◽  
Lucía Arenas-Alfonseca ◽  
Luis C. Romero ◽  
Masashi Yamada
Keyword(s):  
Single Cell ◽  
Root Hair ◽  
Root Hairs ◽  
Quiescent Center ◽  
Wild Type ◽  
Post Translational Modification ◽  
Protein Activity ◽  
Root Hair Development ◽  
Root Hair Formation ◽  
Visible Effect

Root hairs are specialized structures involved in water and nutrient uptake by plants. They elongate from epidermal cells following a complex developmental program. β-cyanoalanine synthase (CAS), which is mainly involved in hydrogen cyanide (HCN) detoxification in Arabidopsis thaliana, plays a role in root hair elongation, as evidenced by the fact that cas-c1 mutants show a severe defect in root hair shape. In addition to root hairs, CAS C1 is expressed in the quiescent center and meristem. However, the cas-c1 mutation has no visible effect on either tissue, in both control and nutrient-deprivation conditions. To identify its role in root hair formation, we conducted single cell proteomics analysis by isolating root hair cells using Fluorescence-Activated Cell Sorting (FACS) from wild type and cas-c1 mutants. We also analyzed the presence of S-cyanylation, a protein post-translational modification (PTM) mediated by HCN and affecting cysteine residues and protein activity, in proteins of wild type and cas-c1 mutants. We found that several proteins involved in root hair development, related to the receptor kinase FERONIA signaling and to DNA methylation, are modified by this new post-translational modification.

Root Hair Specific Proteins in Glycine max

1987 ◽  
Vol 42 (5) ◽  
pp. 537-541 ◽  
Author(s):  
Dietrich Werner ◽  
Andreas Bernd Wolff
Keyword(s):  
Glycine Max ◽  
Root System ◽  
Hair Cells ◽  
Root Hair ◽  
Root Hairs ◽  
Target Cells ◽  
Molecular Weights ◽  
Organ Specific ◽  
Specific Proteins ◽  
Root Hair Cells

Abstract In root hairs from seedlings of Glycine max cultivars, isolated from the root system and com­ pared with the complete organ, specific soluble proteins have been found. By FPLC chromatography and SDS gel electrophoresis root hair specific proteins with molecular weights of 13, 21, 34, 38 and 42 kDa were separated. Additionally, proteins with molecular weights of 12, 20, 69 and 74 kDa were significantly enriched in root hairs compared to roots without root hairs. By using CNBr activated Sepharose with antibodies against the root system without root hairs, the pres­ ence of root hair specific proteins was confirmed in extracts from isolated root hair cells. Enrichment of Fe and Ca in some of the proteins from the root hairs is demonstrated. The present knowledge of the biochemical specificity of legume root hairs, the target cells of Rhizobium and Bradyrhizobium infection, is discussed.

scholarly journals A cell surface arabinogalactan-peptide influences root hair cell fate

2019 ◽  
Author(s):  
Cecilia Borassi ◽  
Javier Gloazzo Dorosz ◽  
Martiniano M. Ricardi ◽  
Laercio Pol Fachin ◽  
Mariana Carignani Sardoy ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Transcription Factor ◽  
Cell Surface ◽  
Cell Fate ◽  
Root Hair ◽  
Root Hairs ◽  
Epidermal Cells ◽  
Root Epidermis ◽  
A Cell ◽  
Epidermis Cell

SummaryRoot hairs (RHs) develop from specialized epidermal cells called trichoblasts, whereas epidermal cells that lack RHs are known as atrichoblasts. The mechanism controlling root epidermal cell fate is only partially understood. Root epidermis cell fate is regulated by a transcription factor complex that promotes the expression of the homeodomain protein GLABRA 2 (GL2), which blocks RH development by inhibiting ROOT HAIR DEFECTIVE 6 (RHD6). Suppression of GL2 expression activates RHD6, a series of downstream TFs including ROOT HAIR DEFECTIVE 6 LIKE-4 (RSL4 [Yi et al. 2010]) and their target genes, and causes epidermal cells to develop into RHs. Brassinosteroids (BRs) influence root epidermis cell fate. In the absence of BRs, phosphorylated BIN2 (a Type-II GSK3-like kinase) inhibits a protein complex that directly downregulates GL2 [Chen et al. 2014]. Here, we show that the genetic and pharmacological perturbation of the arabinogalactan peptide (AG) AGP21 in Arabidopsis thaliana, triggers aberrant RH development, similar to that observed in plants with defective BR signaling. We reveal that an O-glycosylated AGP21 peptide, which is positively regulated by BZR1, a transcription factor activated by BR signaling, affects RH cell fate by altering GL2 expression in a BIN2-dependent manner. These results suggest that perturbation of a cell surface AGP disrupts BR responses and inhibits the downstream effect of BIN2 on the RH repressor GL2 in root epidermal cells. In addition, AGP21 also acts in a BR-independent, AGP-dependent mode that together with BIN2 signalling cascade controls RH cell fate.SignificanceIn the plant Arabidopsis thaliana, the root epidermis forms in an alternating pattern atrichoblasts with trichoblast cells that end up developing root hairs (RHs). Atrichoblast cell fate is directly promoted by the transcription factor GLABRA2 (GL2) while the lack of GL2 allows RH formation. The loss of AGP21 peptide triggers an abnormal RH cell fate in two contiguous cells in a similar manner as brassinosteroid (BRs) mutants. In the absence of BR signaling, BIN2 (a GSK3 like-kinase) in a phosphorylated state, downregulate GL2 expression to trigger RH cell fate. The absence of AGP21 is able to repress GL2 expression and activates the expression of RSL4 and EXP7 root hair proteins.

scholarly journals Interaction of OsRopGEF3 Protein With OsRac3 to Regulate Root Hair Elongation and Reactive Oxygen Species Formation in Rice (Oryza sativa)

2021 ◽  
Vol 12 ◽  
Author(s):  
Eui-Jung Kim ◽  
Woo-Jong Hong ◽  
Win Tun ◽  
Gynheung An ◽  
Sun-Tae Kim ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Root Hair ◽  
Hair Growth ◽  
Root Hairs ◽  
Reactive Oxygen ◽  
Rice Root ◽  
Oxygen Species ◽  
Nucleotide Exchange ◽  
Loss Of Function ◽  
Root Hair Growth

Root hairs are tip-growing cells that emerge from the root epidermis and play a role in water and nutrient uptake. One of the key signaling steps for polar cell elongation is the formation of Rho-GTP by accelerating the intrinsic exchange activity of the Rho-of-plant (ROP) or the Rac GTPase protein; this step is activated through the interaction with the plant Rho guanine nucleotide exchange factor (RopGEFs). The molecular players involved in root hair growth in rice are largely unknown. Here, we performed the functional analysis of OsRopGEF3, which is highly expressed in the root hair tissues among the OsRopGEF family genes in rice. To reveal the role of OsRopGEF3, we analyzed the phenotype of loss-of-function mutants of OsRopGEF3, which were generated using the CRISPR-Cas9 system. The mutants had reduced root hair length and increased root hair width. In addition, we confirmed that reactive oxygen species (ROS) were highly reduced in the root hairs of the osropgef3 mutant. The pairwise yeast two-hybrid experiments between OsRopGEF3 and OsROP/Rac proteins in rice revealed that the OsRopGEF3 protein interacts with OsRac3. This interaction and colocalization at the same subcellular organelles were again verified in tobacco leaf cells and rice root protoplasts via bimolecular functional complementation (BiFC) assay. Furthermore, among the three respiratory burst oxidase homolog (OsRBOH) genes that are highly expressed in rice root hair cells, we found that OsRBOH5 can interact with OsRac3. Our results demonstrate an interaction network model wherein OsRopGEF3 converts the GDP of OsRac3 into GTP, and OsRac3-GTP then interacts with the N-terminal of OsRBOH5 to produce ROS, thereby suggesting OsRopGEF3 as a key regulating factor in rice root hair growth.

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