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.

Localized changes in apoplastic and cytoplasmic pH are associated with root hair development in Arabidopsis thaliana

Development ◽  
1998 ◽  
Vol 125 (15) ◽  
pp. 2925-2934 ◽  
Author(s):  
T.N. Bibikova ◽  
T. Jacob ◽  
I. Dahse ◽  
S. Gilroy
Keyword(s):  
Root Hair ◽  
Tip Growth ◽  
Root Hairs ◽  
Initiation Site ◽  
Cytoplasmic Ph ◽  
Apoplastic Ph ◽  
Initiation Process ◽  
Root Hair Formation ◽  
Root Hair Initiation ◽  
Hair Formation

Morphogenesis in plants is characterized by highly regulated cell enlargement. However, the mechanisms controlling and localizing regions of growth remain essentially unknown. Root hair formation involves the induction of a localized cell expansion in the lateral wall of a root epidermal cell. This expanded region then enters a second phase of localized growth called tip growth. Root hair formation therefore provides a model in which to study the cellular events involved in regulating localized growth in plants. Confocal ratio imaging of the pH of the cell wall revealed an acidification at the root hair initiation site. This acidification was present from the first morphological indications of localized growth, but not before, and was maintained to the point where the process of root hair initiation ceased and tip growth began. Preventing the wall acidification with pH buffers arrested the initiation process but growth resumed when the wall was returned to an acidic pH. Cytoplasmic pH was found to be elevated from approximately 7.3 to 7. 7 at the initiation site, and this elevation coincided with the acidification of the wall. Preventing the localized increase in cytoplasmic pH with 10 mM butyrate however did not inhibit either the wall acidification or the initiation process. In contrast, there was no detectable gradient in pH associated with the apex of tip growing root hairs, but both elevated apoplastic pH and butyrate treatment irreversibly inhibited the tip growth process. Thus the processes of tip growth and initiation of root hairs show differences in their pH requirements. These results highlight the role of localized control of apoplastic pH in the control of cell architecture and morphogenesis in plants.

scholarly journals Rab7 involves Vps35 to mediate AQP2 sorting and apical trafficking in collecting duct cells

2020 ◽  
Vol 318 (4) ◽  
pp. F956-F970 ◽  
Author(s):  
Wei-Ling Wang ◽  
Shih-Han Su ◽  
Kit Yee Wong ◽  
Chan-Wei Yang ◽  
Chin-Fu Liu ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Apical Membrane ◽  
Collecting Duct ◽  
Water Channel ◽  
Small Gtpase ◽  
Apical Plasma Membrane ◽  
Water Reabsorption ◽  
Recycling Endosomes ◽  
Early Endosomes ◽  
Vacuolar Protein

Aquaporin-2 (AQP2) is a vasopressin-regulated water channel protein responsible for osmotic water reabsorption by kidney collecting ducts. In response to vasopressin, AQP2 traffics from intracellular vesicles to the apical plasma membrane of collecting duct principal cells, where it increases water permeability and, hence, water reabsorption. Despite continuing efforts, gaps remain in our knowledge of vasopressin-regulated AQP2 trafficking. Here, we studied the functions of two retromer complex proteins, small GTPase Rab7 and vacuolar protein sorting 35 (Vps35), in vasopressin-induced AQP2 trafficking in a collecting duct cell model (mpkCCD cells). We showed that upon vasopressin removal, apical AQP2 returned to Rab5-positive early endosomes before joining Rab11-positive recycling endosomes. In response to vasopressin, Rab11-associated AQP2 trafficked to the apical plasma membrane before Rab5-associated AQP2 did so. Rab7 knockdown resulted in AQP2 accumulation in early endosomes and impaired vasopressin-induced apical AQP2 trafficking. In response to vasopressin, Rab7 transiently colocalized with Rab5, indicative of a role of Rab7 in AQP2 sorting in early endosomes before trafficking to the apical membrane. Rab7-mediated apical AQP2 trafficking in response to vasopressin required GTPase activity. When Vps35 was knocked down, AQP2 accumulated in recycling endosomes under vehicle conditions and did not traffic to the apical plasma membrane in response to vasopressin. We conclude that Rab7 and Vps35 participate in AQP2 sorting in early endosomes under vehicle conditions and apical membrane trafficking in response to vasopressin.

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 Apical endosomes isolated from kidney collecting duct principal cells lack subunits of the proton pumping ATPase.

1992 ◽  
Vol 119 (1) ◽  
pp. 111-122 ◽  
Author(s):  
I Sabolic ◽  
F Wuarin ◽  
L B Shi ◽  
A S Verkman ◽  
D A Ausiello ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Proton Pump ◽  
Transmembrane Domain ◽  
Collecting Duct ◽  
Water Channels ◽  
Proton Pumping ◽  
Apical Plasma Membrane ◽  
Principal Cells ◽  
Kidney Collecting Duct ◽  
Early Endosomes

Endocytic vesicles that are involved in the vasopressin-stimulated recycling of water channels to and from the apical membrane of kidney collecting duct principal cells were isolated from rat renal papilla by differential and Percoll density gradient centrifugation. Fluorescence quenching measurements showed that the isolated vesicles maintained a high, HgCl2-sensitive water permeability, consistent with the presence of vasopressin-sensitive water channels. They did not, however, exhibit ATP-dependent luminal acidification, nor any N-ethylmaleimide-sensitive ATPase activity, properties that are characteristic of most acidic endosomal compartments. Western blotting with specific antibodies showed that the 31- and 70-kD cytoplasmically oriented subunits of the vacuolar proton pump were not detectable in these apical endosomes from the papilla, whereas they were present in endosomes prepared in parallel from the cortex. In contrast, the 56-kD subunit of the proton pump was abundant in papillary endosomes, and was localized at the apical pole of principal cells by immunocytochemistry. Finally, an antibody that recognizes the 16-kD transmembrane subunit of oat tonoplast ATPase cross-reacted with a distinct 16-kD band in cortical endosomes, but no 16-kD band was detectable in endosomes from the papilla. This antibody also recognized a 16-kD band in affinity-purified H+ ATPase preparations from bovine kidney medulla. Therefore, early endosomes derived from the apical plasma membrane of collecting duct principal cells fail to acidify because they lack functionally important subunits of a vacuolar-type proton pumping ATPase, including the 16-kD transmembrane domain that serves as the proton-conducting channel, and the 70-kD cytoplasmic subunit that contains the ATPase catalytic site. This specialized, non-acidic early endosomal compartment appears to be involved primarily in the hormonally induced recycling of water channels to and from the apical plasma membrane of vasopressin-sensitive cells in the kidney collecting duct.

scholarly journals The Small GTPase ROP10 of Medicago truncatula Is Required for Both Tip Growth of Root Hairs and Nod Factor-Induced Root Hair Deformation

2015 ◽  
Vol 27 (3) ◽  
pp. 806-822 ◽  
Author(s):  
Ming-Juan Lei ◽  
Qi Wang ◽  
Xiaolin Li ◽  
Aimin Chen ◽  
Li Luo ◽  
...  
Keyword(s):  
Medicago Truncatula ◽  
Root Hair ◽  
Tip Growth ◽  
Root Hairs ◽  
Small Gtpase ◽  
Nod Factor ◽  
Root Hair Deformation

scholarly journals Functional Characterization of fer-ts, a Temperature-Sensitive FERONIA Mutant Allele That Alters Root Hair Growth

2020 ◽  
Author(s):  
Daewon Kim ◽  
Jiyuan Yang ◽  
Fangwei Gu ◽  
Sung Jin Park ◽  
Jonathon Combs ◽  
...  
Keyword(s):  
Root Hair ◽  
Plasma Membranes ◽  
Tip Growth ◽  
Elevated Temperatures ◽  
Functional Characterization ◽  
Root Hairs ◽  
Temperature Sensitive ◽  
Genetic Screens ◽  
Binding Domains ◽  
Cellular Components

ABSTRACTIn plants, root hairs undergo a highly-polarized form of cell expansion called tip-growth, in which cell wall deposition is restricted to the root hair apex. In order to identify essential cellular components that might have been missed in earlier genetic screens we identified conditional temperature sensitive (ts) root hair mutants by EMS mutagenesis. Here we describe one of these mutants, fer-ts (feronia-temperature sensitive). Mutant fer-ts seedlings grew normally at normal temperatures (20°C), but failed to form root hairs at elevated temperatures (30°C). Map based-cloning and whole genome sequencing revealed that fer-ts resulted from a G41S substitution in the extracellular domain of FERONIA (FER). A functional fluorescent fusion of FER containing the fer-ts mutation localized to plasma membranes, but was subject to enhanced protein turnover at elevated temperatures. While tip-growth was rapidly inhibited by addition of RALF1 peptides in both wild-type and fer-ts mutants at normal temperatures, root elongation of fer-ts seedlings was resistant to added RALF1 peptide at elevated temperatures. Additionally, at elevated temperatures fer-ts seedlings displayed altered ROS accumulation upon auxin treatment and phenocopied constitutive fer mutant responses to a variety of plant hormone treatments. Molecular modeling and sequence comparison with other CrRLK1L receptor family members revealed that the mutated glycine in fer-ts is highly conserved, but is not located in the recently characterized RALF23 and LORELI-LIKE-GLYCOPROTEIN (LLG2) binding domains, perhaps suggesting that fer-ts phenotypes may not be directly due to loss of binding to RALF1 peptides.

scholarly journals Ethylene promotes root hair growth through coordinated EIN3/EIL1 and RHD6/RSL1 activity in Arabidopsis

2017 ◽  
Vol 114 (52) ◽  
pp. 13834-13839 ◽  
Author(s):  
Ying Feng ◽  
Ping Xu ◽  
Bosheng Li ◽  
Pengpeng Li ◽  
Xing Wen ◽  
...  
Keyword(s):  
Root Hair ◽  
Hair Growth ◽  
Root Hairs ◽  
Environmental Signals ◽  
Environmental Interactions ◽  
Two Factors ◽  
Root Hair Growth ◽  
Transcriptional Complex ◽  
Root Hair Initiation ◽  
Molecular Framework

Root hairs are an extensive structure of root epidermal cells and are critical for nutrient acquisition, soil anchorage, and environmental interactions in sessile plants. The phytohormone ethylene (ET) promotes root hair growth and also mediates the effects of different signals that stimulate hair cell development. However, the molecular basis of ET-induced root hair growth remains poorly understood. Here, we show that ET-activated transcription factor ETHYLENE-INSENSITIVE 3 (EIN3) physically interacts with ROOT HAIR DEFECTIVE 6 (RHD6), a well-documented positive regulator of hair cells, and that the two factors directly coactivate the hair length-determining gene RHD6-LIKE 4 (RSL4) to promote root hair elongation. Transcriptome analysis further revealed the parallel roles of the regulator pairs EIN3/EIL1 (EIN3-LIKE 1) and RHD6/RSL1 (RHD6-LIKE 1). EIN3/EIL1 and RHD6/RSL1 coordinately enhance root hair initiation by selectively regulating a subset of core root hair genes. Thus, our work reveals a key transcriptional complex consisting of EIN3/EIL1 and RHD6/RSL1 in the control of root hair initiation and elongation, and provides a molecular framework for the integration of environmental signals and intrinsic regulators in modulating plant organ development.

Helicoidal microfibril deposition in a tip-growing cell and microtubule alignment during tip morphogenesis: a dry-cleaving and freeze-substitution study

1989 ◽  
Vol 67 (8) ◽  
pp. 2401-2408 ◽  
Author(s):  
Anne Mie C. Emons
Keyword(s):  
Cell Wall ◽  
Plasma Membrane ◽  
Root Hair ◽  
Root Hairs ◽  
Freeze Substitution ◽  
Axial Direction ◽  
Microfibril Orientation ◽  
Growing Cell ◽  
Equisetum Hyemale ◽  
Dry Cleaving

Cell wall microfibril alignment in the tubular portion of Equisetum hyemale root hairs is helicoidal. Lamellae of helicoidal texture are deposited from tip to base; thus, different microfibril orientations are aligned with the plasma membrane successively. Zones with constant mean microfibril orientation are about 300 μm long. In any such zone of dry-cleaned, shadowed preparations, the frequency of microfibrils at the proximal end is 5 to 7 microfibrils per micrometre, which decreases to 0 at the distal end. The orientation of microfibrils of the underlying lamella, the microfibril frequency of which is 5 to 7/μm throughout, is the same as the microfibril orientation of the neighbouring distal lamella. Microfibrils of the cell wall are randomly oriented in the hair dome. Microtubule alignment in these root hairs was examined by means of freeze substitution. In the extreme tip of the root hair, microtubules run parallel to the plasma membrane and transverse to the long axis of the hair; the hemisphere of the hair contains randomly oriented microtubules. From extreme tip to base of the hair dome, microtubules become more and more axially aligned, and remain axially oriented in the hair tube. Further down the hair, where microfibril alignment is transverse and microfibrils are actively being deposited, microtubules still run in the axial direction. The observations emphasize the involvement of microtubles in root hair tip morphogenesis, but not in determining the alignment of the microfibrils in the hair tube.

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.

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