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Chocano-Coralla EJ, Vidali L. Myosin XI, a model of its conserved role in plant cell tip growth. Biochem Soc Trans 2024; 52:505-515. [PMID: 38629612 DOI: 10.1042/bst20220783] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2023] [Revised: 03/21/2024] [Accepted: 03/26/2024] [Indexed: 04/25/2024]
Abstract
In eukaryotic cells, organelle and vesicle transport, positioning, and interactions play crucial roles in cytoplasmic organization and function. These processes are governed by intracellular trafficking mechanisms. At the core of that trafficking, the cytoskeleton and directional transport by motor proteins stand out as its key regulators. Plant cell tip growth is a well-studied example of cytoplasm organization by polarization. This polarization, essential for the cell's function, is driven by the cytoskeleton and its associated motors. This review will focus on myosin XI, a molecular motor critical for vesicle trafficking and polarized plant cell growth. We will center our discussion on recent data from the moss Physcomitrium patens and the liverwort Marchantia polymorpha. The biochemical properties and structure of myosin XI in various plant species are discussed, highlighting functional conservation across species. We further explore this conservation of myosin XI function in the process of vesicle transport in tip-growing cells. Existing evidence indicates that myosin XI actively organizes actin filaments in tip-growing cells by a mechanism based on vesicle clustering at their tips. A hypothetical model is presented to explain the essential function of myosin XI in polarized plant cell growth based on vesicle clustering at the tip. The review also provides insight into the in vivo localization and dynamics of myosin XI, emphasizing its role in cytosolic calcium regulation, which influences the polymerization of F-actin. Lastly, we touch upon the need for additional research to elucidate the regulation of myosin function.
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Affiliation(s)
| | - Luis Vidali
- Department of Biology and Biotechnology, Worcester Polytechnic Institute, Worcester, MA, U.S.A
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2
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Ntefidou M, Eklund DM, Le Bail A, Schulmeister S, Scherbel F, Brandl L, Dörfler W, Eichstädt C, Bannmüller A, Ljung K, Kost B. Physcomitrium patens PpRIC, an ancestral CRIB-domain ROP effector, inhibits auxin-induced differentiation of apical initial cells. Cell Rep 2023; 42:112130. [PMID: 36790931 DOI: 10.1016/j.celrep.2023.112130] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2022] [Revised: 12/03/2022] [Accepted: 02/01/2023] [Indexed: 02/16/2023] Open
Abstract
RHO guanosine triphosphatases are important eukaryotic regulators of cell differentiation and behavior. Plant ROP (RHO of plant) family members activate specific, incompletely characterized downstream signaling. The structurally simple land plant Physcomitrium patens is missing homologs of key animal and flowering plant RHO effectors but contains a single CRIB (CDC42/RAC interactive binding)-domain-containing RIC (ROP-interacting CRIB-containing) protein (PpRIC). Protonemal P. patens filaments elongate based on regular division and PpROP-dependent tip growth of apical initial cells, which upon stimulation by the hormone auxin differentiate caulonemal characteristics. PpRIC interacts with active PpROP1, co-localizes with this protein at the plasma membrane at the tip of apical initial cells, and accumulates in the nucleus. Remarkably, PpRIC is not required for tip growth but is targeted to the nucleus to block caulonema differentiation downstream of auxin-controlled gene expression. These observations establish functions of PpRIC in mediating crosstalk between ROP and auxin signaling, which contributes to the maintenance of apical initial cell identity.
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Affiliation(s)
- Maria Ntefidou
- Cell Biology, Department of Biology, University Erlangen-Nuremberg, 91058 Erlangen, Germany
| | - D Magnus Eklund
- Physiology and Environmental Toxicology, Department of Organismal Biology, Uppsala University, 75236 Uppsala, Sweden
| | - Aude Le Bail
- Cell Biology, Department of Biology, University Erlangen-Nuremberg, 91058 Erlangen, Germany
| | - Sylwia Schulmeister
- Cell Biology, Department of Biology, University Erlangen-Nuremberg, 91058 Erlangen, Germany
| | - Franziska Scherbel
- Cell Biology, Department of Biology, University Erlangen-Nuremberg, 91058 Erlangen, Germany
| | - Lisa Brandl
- Cell Biology, Department of Biology, University Erlangen-Nuremberg, 91058 Erlangen, Germany
| | - Wolfgang Dörfler
- Cell Biology, Department of Biology, University Erlangen-Nuremberg, 91058 Erlangen, Germany
| | - Chantal Eichstädt
- Cell Biology, Department of Biology, University Erlangen-Nuremberg, 91058 Erlangen, Germany
| | - Anna Bannmüller
- Cell Biology, Department of Biology, University Erlangen-Nuremberg, 91058 Erlangen, Germany
| | - Karin Ljung
- Umeå Plant Science Centre, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, 90183 Umeå, Sweden
| | - Benedikt Kost
- Cell Biology, Department of Biology, University Erlangen-Nuremberg, 91058 Erlangen, Germany.
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Mugume Y, Roy R, Agbemafle W, Shepard GN, Vue Y, Bassham DC. VPS45 is required for both diffuse and tip growth of Arabidopsis thaliana cells. Front Plant Sci 2023; 14:1120307. [PMID: 36923123 PMCID: PMC10009167 DOI: 10.3389/fpls.2023.1120307] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/09/2022] [Accepted: 02/07/2023] [Indexed: 06/18/2023]
Abstract
INTRODUCTION VPS45 belongs to the Sec1/Munc18 family of proteins, which interact with and regulate Qa-SNARE function during membrane fusion. We have shown previously that Arabidopsis thaliana VPS45 interacts with the SYP61/SYP41/VTI12 SNARE complex, which locates on the trans-Golgi network (TGN). It is required for SYP41 stability, and it functions in cargo trafficking to the vacuole and in cell expansion. It is also required for correct auxin distribution during gravitropism and lateral root growth. RESULTS As vps45 knockout mutation is lethal in Arabidopsis, we identified a mutant, vps45-3, with a point mutation in the VPS45 gene causing a serine 284-to-phenylalanine substitution. The VPS45-3 protein is stable and maintains interaction with SYP61 and SYP41. However, vps45-3 plants display severe growth defects with significantly reduced organ and cell size, similar to vps45 RNAi transgenic lines that have reduced VPS45 protein levels. Root hair and pollen tube elongation, both processes of tip growth, are highly compromised in vps45-3. Mutant root hairs are shorter and thicker than those of wild-type plants, and are wavy. These root hairs have vacuolar defects, containing many small vacuoles, compared with WT root hairs with a single large vacuole occupying much of the cell volume. Pollen tubes were also significantly shorter in vps45-3 compared to WT. DISCUSSION We thus show that VPS45 is essential for proper tip growth and propose that the observed vacuolar defects lead to loss of the turgor pressure needed for tip growth.
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Affiliation(s)
- Yosia Mugume
- Department of Genetics, Development and Cell Biology, Iowa State University, Ames, IA, United States
| | - Rahul Roy
- Department of Genetics, Development and Cell Biology, Iowa State University, Ames, IA, United States
| | - William Agbemafle
- Roy J. Carver Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University, Ames, IA, United States
| | - Gabriella N. Shepard
- Department of Genetics, Development and Cell Biology, Iowa State University, Ames, IA, United States
| | - Yee Vue
- Department of Genetics, Development and Cell Biology, Iowa State University, Ames, IA, United States
| | - Diane C. Bassham
- Department of Genetics, Development and Cell Biology, Iowa State University, Ames, IA, United States
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Park CJ, Ha J, Lee HR, Park K, Sun JY, Kim HY. Plant cell-like tip-growing polymer precipitate with structurally embedded multistimuli sensing ability. Proc Natl Acad Sci U S A 2023; 120:e2211416120. [PMID: 36595665 DOI: 10.1073/pnas.2211416120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Soft systems that respond to external stimuli, such as heat, magnetic field, and light, find applications in a range of fields including soft robotics, energy harvesting, and biomedicine. However, most of the existing systems exhibit nondirectional, nastic movement as they can neither grow nor sense the direction of stimuli. In this regard, artificial systems are outperformed by organisms capable of directional growth in response to the sense of stimuli or tropic growth. Inspired by tropic growth schemes of plant cells and fungal hyphae, here we report an artificial multistimuli-responsive tropic tip-growing system based on nonsolvent-induced phase separation of polymer solution, where polymer precipitates as its solvent dissolves into surrounding nonsolvent. We provide a theoretical framework to predict the size and velocity of growing precipitates and demonstrate its capability of sensing the directions of gravity, mechanical contact, and light and adjusting its growing direction in response. Exploiting the embedded physical intelligence of sensing and responding to external stimuli, our soft material system achieves multiple tasks including printing 3D structures in a confined space, bypassing mechanical obstacles, and shielded transport of liquids within water.
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Serrano N, Pejchar P, Soukupová H, Hubálek M, Potocký M. Comprehensive analysis of glycerolipid dynamics during tobacco pollen germination and pollen tube growth. Front Plant Sci 2022; 13:1028311. [PMID: 36426152 PMCID: PMC9679300 DOI: 10.3389/fpls.2022.1028311] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/2022] [Accepted: 10/11/2022] [Indexed: 06/12/2023]
Abstract
Pollen germination and subsequent pollen tube elongation are essential for successful land plant reproduction. These processes are achieved through well-documented activation of membrane trafficking and cell metabolism. Despite this, our knowledge of the dynamics of cellular phospholipids remains scarce. Here we present the turnover of the glycerolipid composition during the establishment of cell polarity and elongation processes in tobacco pollen and show the lipid composition of pollen plasma membrane-enriched fraction for the first time. To achieve this, we have combined several techniques, such as lipidomics, plasma membrane isolation, and live-cell microscopy, and performed a study with different time points during the pollen germination and pollen tube growth. Our results showed that tobacco pollen tubes undergo substantial changes in their whole-cell lipid composition during the pollen germination and growth, finding differences in most of the glycerolipids analyzed. Notably, while lysophospholipid levels decrease during germination and growth, phosphatidic acid increases significantly at cell polarity establishment and continues with similar abundance in cell elongation. We corroborated these findings by measuring several phospholipase activities in situ. We also observed that lysophospholipids and phosphatidic acid are more abundant in the plasma membrane-enriched fraction than that in the whole cell. Our results support the important role for the phosphatidic acid in the establishment and maintenance of cellular polarity in tobacco pollen tubes and indicate that plasma membrane lysophospholipids may be involved in pollen germination.
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Affiliation(s)
- Natalia Serrano
- Institute of Experimental Botany of the Czech Academy of Sciences, Prague, Czechia
| | - Přemysl Pejchar
- Institute of Experimental Botany of the Czech Academy of Sciences, Prague, Czechia
| | - Hana Soukupová
- Institute of Experimental Botany of the Czech Academy of Sciences, Prague, Czechia
| | - Martin Hubálek
- Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, Prague, Czechia
| | - Martin Potocký
- Institute of Experimental Botany of the Czech Academy of Sciences, Prague, Czechia
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Abstract
Polar cell growth in plants requires a cell peripheral region that undergoes membrane extension and cell wall remodeling. Since the 1990s, RHO-RELATED GTPASES FROM PLANTS (ROPs) have been identified as master regulators that determine the site of cell growth. ROPs function to regulate actin and microtubule cytoskeletons, calcium gradients, and exocytosis, thus directing the delivery of materials for membrane and cell wall extension. In recent years, our understanding of the regulatory mechanisms underlying polar localization and the activation of ROPs has greatly advanced. Evidence points to the crucial roles of membrane lipids, receptor-like kinases, and cell wall components. In this review, we provide updates on the mechanisms underlying polarity control in tip-growing cells, with a focus on ROP effectors and membrane-associated signals. By integrating knowledge from pollen tubes, root hairs, and findings in bryophyte protonema cells and rhizoids, we hope to offer important insights into a common conceptual framework on polarity establishment governed by intercellular and extracellular signals.
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Affiliation(s)
- Hongxin Ou
- Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, Sichuan, 610065, China
| | - Peishan Yi
- Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, Sichuan, 610065, China
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Lara-Mondragón CM, Dorchak A, MacAlister CA. O-glycosylation of the extracellular domain of pollen class I formins modulates their plasma membrane mobility. J Exp Bot 2022; 73:3929-3945. [PMID: 35383367 PMCID: PMC9232206 DOI: 10.1093/jxb/erac131] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Accepted: 03/31/2022] [Indexed: 06/09/2023]
Abstract
In plant cells, linkage between the cytoskeleton, plasma membrane, and cell wall is crucial for maintaining cell shape. In highly polarized pollen tubes, this coordination is especially important to allow rapid tip growth and successful fertilization. Class I formins contain cytoplasmic actin-nucleating formin homology domains as well as a proline-rich extracellular domain and are candidate coordination factors. Here, using Arabidopsis, we investigated the functional significance of the extracellular domain of two pollen-expressed class I formins: AtFH3, which does not have a polar localization, and AtFH5, which is limited to the growing tip region. We show that the extracellular domain of both is necessary for their function, and identify distinct O-glycans attached to these sequences, AtFH5 being hydroxyproline-arabinosylated and AtFH3 carrying arabinogalactan chains. Loss of hydroxyproline arabinosylation altered the plasma membrane localization of AtFH5 and disrupted actin cytoskeleton organization. Moreover, we show that O-glycans differentially affect lateral mobility in the plasma membrane. Together, our results support a model of protein sub-functionalization in which AtFH5 and AtFH3, restricted to specific plasma membrane domains by their extracellular domains and the glycans attached to them, organize distinct subarrays of actin during pollen tube elongation.
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Affiliation(s)
- Cecilia M Lara-Mondragón
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
| | - Alexandria Dorchak
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
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Cui X, Wang S, Huang Y, Ding X, Wang Z, Zheng L, Bi Y, Ge F, Zhu L, Yuan M, Yalovsky S, Fu Y. Arabidopsis SYP121 acts as an ROP2 effector in the regulation of root hair tip growth. Mol Plant 2022; 15:1008-1023. [PMID: 35488430 DOI: 10.1016/j.molp.2022.04.008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2021] [Revised: 04/04/2022] [Accepted: 04/25/2022] [Indexed: 06/14/2023]
Abstract
Tip growth is an extreme form of polarized cell expansion that occurs in all eukaryotic kingdoms to generate highly elongated tubular cells with specialized functions, including fungal hyphae, animal neurons, plant pollen tubes, and root hairs (RHs). RHs are tubular structures that protrude from the root epidermis to facilitate water and nutrient uptake, microbial interactions, and plant anchorage. RH tip growth requires polarized vesicle targeting and active exocytosis at apical growth sites. However, how apical exocytosis is spatially and temporally controlled during tip growth remains elusive. Here, we report that the Qa-Soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) SYP121 acts as an effector of Rho of Plants 2 (ROP2), mediating the regulation of RH tip growth. We show that active ROP2 promotes SYP121 targeting to the apical plasma membrane. Moreover, ROP2 directly interacts with SYP121 and promotes the interaction between SYP121 and the R-SNARE VAMP722 to form a SNARE complex, probably by facilitating the release of the Sec1/Munc18 protein SEC11, which suppresses the function of SYP121. Thus, the ROP2-SYP121 pathway facilitates exocytic trafficking during RH tip growth. Our study uncovers a direct link between an ROP GTPase and vesicular trafficking and a new mechanism for the control of apical exocytosis, whereby ROP GTPase signaling spatially regulates SNARE complex assembly and the polar distribution of a Q-SNARE.
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Affiliation(s)
- Xiankui Cui
- State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing 100193, China
| | - Shuwei Wang
- State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing 100193, China
| | - Yaohui Huang
- State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing 100193, China
| | - Xuening Ding
- State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing 100193, China
| | - Zirong Wang
- State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing 100193, China
| | - Lidan Zheng
- State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing 100193, China
| | - Yujing Bi
- State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing 100193, China
| | - Fanghui Ge
- State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing 100193, China
| | - Lei Zhu
- State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing 100193, China; Joint Laboratory for International Cooperation in Crop Molecular Breeding, Ministry of Education, China Agricultural University, Beijing 100193, China
| | - Ming Yuan
- State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing 100193, China
| | - Shaul Yalovsky
- Department of Plant Sciences, Tel Aviv University, Tel Aviv 69978, Israel
| | - Ying Fu
- State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing 100193, China; Joint Laboratory for International Cooperation in Crop Molecular Breeding, Ministry of Education, China Agricultural University, Beijing 100193, China.
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9
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Ginanjar EF, Teh OK, Fujita T. Characterisation of rapid alkalinisation factors in Physcomitrium patens reveals functional conservation in tip growth. New Phytol 2022; 233:2442-2457. [PMID: 34954833 DOI: 10.1111/nph.17942] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/15/2021] [Accepted: 12/17/2021] [Indexed: 06/14/2023]
Abstract
Small signalling peptides are key molecules for cell-to-cell communications in plants. The cysteine-rich signalling peptide, rapid alkalinisation factors (RALFs) family are involved in diverse developmental and stress responses and have expanded considerably during land plant evolution, implying neofunctionalisations in the RALF family. However, the ancestral roles of RALFs when land plant first acquired them remain unknown. Here, we functionally characterised two of the three RALFs in bryophyte Physcomitrium patens using loss-of-function mutants, overexpressors, as well as fluorescent proteins tagged reporter lines. We showed that PpRALF1 and PpRALF2 have overlapping functions in promoting protonema tip growth and elongation, showing a homologous function as the Arabidopsis RALF1 in promoting root hair tip growth. Although both PpRALFs are secreted to the plasma membrane on which PpRALF1 symmetrically localised, PpRALF2 showed a polarised localisation at the growing tip. Notably, proteolytic cleavage of PpRALF1 is necessary for its function. Our data reveal a possible evolutionary origin of the RALF functions and suggest that functional divergence of RALFs is essential to drive complex morphogenesis and to facilitate other novel processes in land plants.
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Affiliation(s)
| | - Ooi-Kock Teh
- Faculty of Science, Hokkaido University, Hokkaido, 060-0810, Japan
- Institute for the Advancement of Higher Education, Hokkaihdo University, Sapporo, 060-0817, Japan
- Institute of Plant and Microbial Biology, Academia Sinica, 128 Sec.2, Academia Rd, Nankang, Taipei, Taiwan
| | - Tomomichi Fujita
- Faculty of Science, Hokkaido University, Hokkaido, 060-0810, Japan
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Hiwatashi Y, Shimada M, Mikami K, Takada N. Establishment of a Live-Imaging Analysis for Polarized Growth of Conchocelis in the Multicellular Red Alga Neopyropia yezoensis. Front Plant Sci 2022; 12:716011. [PMID: 35251057 PMCID: PMC8888420 DOI: 10.3389/fpls.2021.716011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Accepted: 12/27/2021] [Indexed: 06/14/2023]
Abstract
A wide range of tip-growing cells in plants display polarized cell growth, which is an essential cellular process for the form and function of individual cells. Understanding of the regulatory mechanisms underlying tip growth in terrestrial plants has improved. Cellular processes involved in tip growth have also been investigated in some algae species that form filamentous cells, but their regulatory mechanisms remain unclear. In the macro red alga Neopyropia yezoensis, for which genome information has recently been released, the conchocelis apical cell exhibits tip growth and forms a filamentous structure. Here, we report a live-imaging technique using high-resolution microscopy to analyze the tip growth and cell division of N. yezoensis conchocelis. This imaging analysis addressed tip growth dynamics and cell division in conchocelis apical cells. The directionality and tip growth expansion were disrupted by the application of cytoskeletal drugs, suggesting the involvement of microtubules (MTs) and actin filaments (AFs) in these processes. A growing apical cell mostly contained a single chloroplast that moved toward the expanding part of the apical cell. Drug application also inhibited chloroplast movement, implying that the movement may be dependent on the cytoskeleton. The study determined that live-imaging analysis is a versatile approach for exploring the dynamics of tip growth and cell division in N. yezoensis conchocelis, which provides insights into the regulatory mechanisms underlying cellular growth in multicellular red algae.
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Affiliation(s)
- Yuji Hiwatashi
- Graduate School of Food, Agricultural and Environmental Sciences, Miyagi University, Sendai, Japan
- School of Food Industrial Sciences, Miyagi University, Sendai, Japan
| | - Mizuho Shimada
- Graduate School of Food, Agricultural and Environmental Sciences, Miyagi University, Sendai, Japan
| | - Koji Mikami
- Graduate School of Food, Agricultural and Environmental Sciences, Miyagi University, Sendai, Japan
- School of Food Industrial Sciences, Miyagi University, Sendai, Japan
| | - Nagisa Takada
- School of Food Industrial Sciences, Miyagi University, Sendai, Japan
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11
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Scheible N, Yoon GM, McCubbin AG. Calmodulin Domain Protein Kinase PiCDPK1 Regulates Pollen Tube Growth Polarity through Interaction with RhoGDI. Plants (Basel) 2022; 11:plants11030254. [PMID: 35161234 PMCID: PMC8838988 DOI: 10.3390/plants11030254] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/30/2021] [Revised: 01/14/2022] [Accepted: 01/17/2022] [Indexed: 05/14/2023]
Abstract
The pollen-specific calcium-dependent protein kinase PiCDPK1 of Petunia inflata has previously been shown to regulate polarity in tip growth in pollen tubes. Here we report the identification of a Rho Guanine Dissociation Inhibitor (PiRhoGDI1) as a PiCDPK1 interacting protein. We demonstrate that PiRhoGDI1 and PiCDPK1 interact in a yeast 2-hybrid assay, as well as in an in vitro pull-down assay, and that PiRhoGDI1 is phosphorylated by PiCDPK1 in vitro. We further demonstrate the PiRhoGDI1 is capable of rescuing the loss of growth polarity phenotype caused by over-expressing PiCDPK1 in vivo using stable transgenic plants. We confirmed that PiRhoGDI1 interacts with a pollen-expressed ROP GTPase isoform consistent with the established role of RhoGDIs in negatively regulating GTPases through their membrane removal and locking them in an inactive cytosolic complex. ROP is a central regulator of polarity in tip growth, upstream of Ca2+, and PiCDPK1 over-expression has been previously reported to lead to dramatic elevation of cytosolic Ca2+ through a positive feedback loop. The discovery that PiCDPK1 impacts ROP regulation via PiRhoGDI1 suggests that PiCDPK1 acts as RhoGDI displacement factor and leads us to propose a model which we hypothesize regulates the rapid recycling of ROP GTPase at the pollen tube tip.
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12
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Pertl-Obermeyer H, Gimeno A, Kuchler V, Servili E, Huang S, Fang H, Lang V, Sydow K, Pöckl M, Schulze WX, Obermeyer G. pH modulates interaction of 14-3-3 proteins with pollen plasma membrane H+ ATPases independently from phosphorylation. J Exp Bot 2022; 73:168-181. [PMID: 34467995 DOI: 10.1093/jxb/erab387] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2021] [Accepted: 08/23/2021] [Indexed: 06/13/2023]
Abstract
Pollen grains transport the sperm cells through the style tissue via a fast-growing pollen tube to the ovaries where fertilization takes place. Pollen tube growth requires a precisely regulated network of cellular as well as molecular events including the activity of the plasma membrane H+ ATPase, which is known to be regulated by reversible protein phosphorylation and subsequent binding of 14-3-3 isoforms. Immunodetection of the phosphorylated penultimate threonine residue of the pollen plasma membrane H+ ATPase (LilHA1) of Lilium longiflorum pollen revealed a sudden increase in phosphorylation with the start of pollen tube growth. In addition to phosphorylation, pH modulated the binding of 14-3-3 isoforms to the regulatory domain of the H+ ATPase, whereas metabolic components had only small effects on 14-3-3 binding, as tested with in vitro assays using recombinant 14-3-3 isoforms and phosphomimicking substitutions of the threonine residue. Consequently, local H+ influxes and effluxes as well as pH gradients in the pollen tube tip are generated by localized regulation of the H+ ATPase activity rather than by heterogeneous localized distribution in the plasma membrane.
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Affiliation(s)
- Heidi Pertl-Obermeyer
- Membrane Biophysics, Department of Biosciences, University of Salzburg, Billrothstr. 11, 5020 Salzburg, Austria
- MorphoPhysics, Department of Chemistry and Physics of Materials, University of Salzburg, Jakob-Haringer-Str. 2a, 5020 Salzburg, Austria
| | - Ana Gimeno
- Membrane Biophysics, Department of Biosciences, University of Salzburg, Billrothstr. 11, 5020 Salzburg, Austria
| | - Verena Kuchler
- Membrane Biophysics, Department of Biosciences, University of Salzburg, Billrothstr. 11, 5020 Salzburg, Austria
| | - Evrim Servili
- Membrane Biophysics, Department of Biosciences, University of Salzburg, Billrothstr. 11, 5020 Salzburg, Austria
- Inst. Recherche Experimentale & Clinique, University of Louvain, Ave. Hippocrate, Woluwe-Saint Lambert, Belgium
| | - Shuai Huang
- Membrane Biophysics, Department of Biosciences, University of Salzburg, Billrothstr. 11, 5020 Salzburg, Austria
- Southern University of Science and Technology, Shenzen, PR China
| | - Han Fang
- Membrane Biophysics, Department of Biosciences, University of Salzburg, Billrothstr. 11, 5020 Salzburg, Austria
- Spinal Chord Injury & Tissue Regeneration Centre, Paracelsus Medical University, Strubergasse, Salzburg, Austria
| | - Veronika Lang
- Membrane Biophysics, Department of Biosciences, University of Salzburg, Billrothstr. 11, 5020 Salzburg, Austria
- STRATEC GmbH, Sonystraße 20, Anif, Austria
| | - Katharina Sydow
- Membrane Biophysics, Department of Biosciences, University of Salzburg, Billrothstr. 11, 5020 Salzburg, Austria
| | - Magdalena Pöckl
- Membrane Biophysics, Department of Biosciences, University of Salzburg, Billrothstr. 11, 5020 Salzburg, Austria
| | - Waltraud X Schulze
- Plant Systems Biology, University of Hohenheim, Garbenstraße 30, 70599 Stuttgart, Germany
| | - Gerhard Obermeyer
- Membrane Biophysics, Department of Biosciences, University of Salzburg, Billrothstr. 11, 5020 Salzburg, Austria
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Abstract
Root hairs are tubular outgrowths of epidermal cells that increase the root surface area and thereby make the root more efficient at absorbing water and nutrients. Their expansion is limited to the root hair apex, where growth is reported to take place in a pulsating manner. These growth pulses coincide with oscillations of the apoplastic and cytosolic pH in a similar way as has been reported for pollen tubes. Likewise, the concentrations of apoplastic reactive oxygen species (ROS) and cytoplasmic Ca2+ oscillate with the same periodicity as growth. Whereas ROS appear to control cell wall extensibility and opening of Ca2+ channels, the role of protons as a growth signal in root hairs is less clear and may differ from that in pollen tubes where plasma membrane H+-ATPases have been shown to sustain growth. In this review, we outline our current understanding of how pH contributes to root hair development.
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Gajek K, Janiak A, Korotko U, Chmielewska B, Marzec M, Szarejko I. Whole Exome Sequencing-Based Identification of a Novel Gene Involved in Root Hair Development in Barley ( Hordeum vulgare L.). Int J Mol Sci 2021; 22:ijms222413411. [PMID: 34948205 PMCID: PMC8709170 DOI: 10.3390/ijms222413411] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Revised: 11/26/2021] [Accepted: 12/09/2021] [Indexed: 12/30/2022] Open
Abstract
Root hairs play a crucial role in anchoring plants in soil, interaction with microorganisms and nutrient uptake from the rhizosphere. In contrast to Arabidopsis, there is a limited knowledge of root hair morphogenesis in monocots, including barley (Hordeum vulgare L.). We have isolated barley mutant rhp1.e with an abnormal root hair phenotype after chemical mutagenesis of spring cultivar ‘Sebastian’. The development of root hairs was initiated in the mutant but inhibited at the very early stage of tip growth. The length of root hairs reached only 3% of the length of parent cultivar. Using a whole exome sequencing (WES) approach, we identified G1674A mutation in the HORVU1Hr1G077230 gene, located on chromosome 1HL and encoding a cellulose synthase-like C1 protein (HvCSLC1) that might be involved in the xyloglucan (XyG) synthesis in root hairs. The identified mutation led to the retention of the second intron and premature termination of the HvCSLC1 protein. The mutation co-segregated with the abnormal root hair phenotype in the F2 progeny of rhp1.e mutant and its wild-type parent. Additionally, different substitutions in HORVU1Hr1G077230 were found in four other allelic mutants with the same root hair phenotype. Here, we discuss the putative role of HvCSLC1 protein in root hair tube elongation in barley.
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Affiliation(s)
- Katarzyna Gajek
- Institute of Biology, Biotechnology and Environmental Protection, Faculty of Natural Sciences, University of Silesia, 40-032 Katowice, Poland; (K.G.); (A.J.); (B.C.); (M.M.)
| | - Agnieszka Janiak
- Institute of Biology, Biotechnology and Environmental Protection, Faculty of Natural Sciences, University of Silesia, 40-032 Katowice, Poland; (K.G.); (A.J.); (B.C.); (M.M.)
| | - Urszula Korotko
- Centre for Bioinformatics and Data Analysis, Medical University of Bialystok, 15-089 Bialystok, Poland;
| | - Beata Chmielewska
- Institute of Biology, Biotechnology and Environmental Protection, Faculty of Natural Sciences, University of Silesia, 40-032 Katowice, Poland; (K.G.); (A.J.); (B.C.); (M.M.)
| | - Marek Marzec
- Institute of Biology, Biotechnology and Environmental Protection, Faculty of Natural Sciences, University of Silesia, 40-032 Katowice, Poland; (K.G.); (A.J.); (B.C.); (M.M.)
| | - Iwona Szarejko
- Institute of Biology, Biotechnology and Environmental Protection, Faculty of Natural Sciences, University of Silesia, 40-032 Katowice, Poland; (K.G.); (A.J.); (B.C.); (M.M.)
- Correspondence:
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15
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Abstract
All kingdoms of life have evolved tip-growing cells able to mine their environment or deliver cargo to remote targets. The basic cellular processes supporting these functions are understood in increasing detail, but the multiple interactions between them lead to complex responses that require quantitative models to be disentangled. Here, I review the equations that capture the fundamental interactions between wall mechanics and cell hydraulics starting with a detailed presentation of James Lockhart's seminal model. The homeostatic feedbacks needed to maintain a steady tip velocity are then shown to offer a credible explanation for the pulsatile growth observed in some tip-growing cells. Turgor pressure emerges as a central variable whose role in the morphogenetic process has been a source of controversy for more than 50 yr. I argue that recasting Lockhart's work as a process of chemical stress relaxation can clarify how cells control tip growth and help us internalise the important but passive role played by turgor pressure in the morphogenetic process.
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Affiliation(s)
- Jacques Dumais
- Faculty of Engineering and Sciences, Universidad Adolfo Ibáñez, Av. Padre Hurtado 750, Viña del Mar, Region of Valparaíso, Chile
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16
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Kollárová E, Baquero Forero A, Cvrčková F. The Arabidopsis thaliana Class II Formin FH13 Modulates Pollen Tube Growth. Front Plant Sci 2021; 12:599961. [PMID: 33679824 PMCID: PMC7929981 DOI: 10.3389/fpls.2021.599961] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Accepted: 01/29/2021] [Indexed: 05/10/2023]
Abstract
Formins are a large, evolutionarily conserved family of actin-nucleating proteins with additional roles in regulating microfilament, microtubule, and membrane dynamics. Angiosperm formins, expressed in both sporophytic and gametophytic tissues, can be divided into two subfamilies, Class I and Class II, each often exhibiting characteristic domain organization. Gametophytically expressed Class I formins have been documented to mediate plasma membrane-based actin assembly in pollen grains and pollen tubes, contributing to proper pollen germination and pollen tube tip growth, and a rice Class II formin, FH5/RMD, has been proposed to act as a positive regulator of pollen tube growth based on mutant phenotype and overexpression data. Here we report functional characterization of the Arabidopsis thaliana pollen-expressed typical Class II formin FH13 (At5g58160). Consistent with published transcriptome data, live-cell imaging in transgenic plants expressing fluorescent protein-tagged FH13 under the control of the FH13 promoter revealed expression in pollen and pollen tubes with non-homogeneous signal distribution in pollen tube cytoplasm, suggesting that this formin functions in the male gametophyte. Surprisingly, fh13 loss of function mutations do not affect plant fertility but result in stimulation of in vitro pollen tube growth, while tagged FH13 overexpression inhibits pollen tube elongation. Pollen tubes of mutants expressing a fluorescent actin marker exhibited possible minor alterations of actin organization. Our results thus indicate that FH13 controls or limits pollen tube growth, or, more generally, that typical Class II formins should be understood as modulators of pollen tube elongation rather than merely components of the molecular apparatus executing tip growth.
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17
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Sun X, Qiu Y, Peng Y, Ning J, Song G, Yang Y, Deng M, Men Y, Zhao X, Wang Y, Guo H, Tian Y. Close Temporal Relationship between Oscillating Cytosolic K + and Growth in Root Hairs of Arabidopsis. Int J Mol Sci 2020; 21:E6184. [PMID: 32867067 DOI: 10.3390/ijms21176184] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2020] [Revised: 08/17/2020] [Accepted: 08/21/2020] [Indexed: 02/06/2023] Open
Abstract
Root hair elongation relies on polarized cell expansion at the growing tip. As a major osmotically active ion, potassium is expected to be continuously assimilated to maintain cell turgor during hair tip growth. However, due to the lack of practicable detection methods, the dynamics and physiological role of K+ in hair growth are still unclear. In this report, we apply the small-molecule fluorescent K+ sensor NK3 in Arabidopsis root hairs for the first time. By employing NK3, oscillating cytoplasmic K+ dynamics can be resolved at the tip of growing root hairs, similar to the growth oscillation pattern. Cross-correlation analysis indicates that K+ oscillation leads the growth oscillations by approximately 1.5 s. Artificially increasing cytoplasmic K+ level showed no significant influence on hair growth rate, but led to the formation of swelling structures at the tip, an increase of cytosolic Ca2+ level and microfilament depolymerization, implying the involvement of antagonistic regulatory factors (e.g., Ca2+ signaling) in the causality between cytoplasmic K+ and hair growth. These results suggest that, in each round of oscillating root hair elongation, the oscillatory cell expansion accelerates on the heels of cytosolic K+ increment, and decelerates with the activation of antagonistic regulators, thus forming a negative feedback loop which ensures the normal growth of root hairs.
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18
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Beuder S, Dorchak A, Bhide A, Moeller SR, Petersen BL, MacAlister CA. Exocyst mutants suppress pollen tube growth and cell wall structural defects of hydroxyproline O-arabinosyltransferase mutants. Plant J 2020; 103:1399-1419. [PMID: 32391581 PMCID: PMC7496944 DOI: 10.1111/tpj.14808] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2020] [Revised: 04/22/2020] [Accepted: 04/28/2020] [Indexed: 05/07/2023]
Abstract
HYDROXYPROLINE O-ARABINOSYLTRANSFERASEs (HPATs) initiate a post-translational protein modification (Hyp-Ara) found abundantly on cell wall structural proteins. In Arabidopsis thaliana, HPAT1 and HPAT3 are redundantly required for full pollen fertility. In addition to the lack of Hyp-Ara in hpat1/3 pollen tubes (PTs), we also found broadly disrupted cell wall polymer distributions, particularly the conversion of the tip cell wall to a more shaft-like state. Mutant PTs were slow growing and prone to rupture and morphological irregularities. In a forward mutagenesis screen for suppressors of the hpat1/3 low seed-set phenotype, we identified a missense mutation in exo70a2, a predicted member of the vesicle-tethering exocyst complex. The suppressed pollen had increased fertility, fewer morphological defects and partially rescued cell wall organization. A transcriptional null allele of exo70a2 also suppressed the hpat1/3 fertility phenotype, as did mutants of core exocyst complex member sec15a, indicating that reduced exocyst function bypassed the PT requirement for Hyp-Ara. In a wild-type background, exo70a2 reduced male transmission efficiency, lowered pollen germination frequency and slowed PT elongation. EXO70A2 also localized to the PT tip plasma membrane, consistent with a role in exocyst-mediated secretion. To monitor the trafficking of Hyp-Ara modified proteins, we generated an HPAT-targeted fluorescent secretion reporter. Reporter secretion was partially dependent on EXO70A2 and was significantly increased in hpat1/3 PTs compared with the wild type, but was reduced in the suppressed exo70a2 hpat1/3 tubes.
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Affiliation(s)
- Steven Beuder
- Department of Molecular, Cellular and Developmental BiologyUniversity of Michigan1105 N. University AveAnn ArborMI48109USA
| | - Alexandria Dorchak
- Department of Molecular, Cellular and Developmental BiologyUniversity of Michigan1105 N. University AveAnn ArborMI48109USA
| | - Ashwini Bhide
- Department of Molecular, Cellular and Developmental BiologyUniversity of Michigan1105 N. University AveAnn ArborMI48109USA
| | - Svenning Rune Moeller
- Department of Plant and Environmental SciencesFaculty of ScienceUniversity of CopenhagenThorvaldsensvej 40København1871 Frederiksberg CDenmark
| | - Bent L. Petersen
- Department of Plant and Environmental SciencesFaculty of ScienceUniversity of CopenhagenThorvaldsensvej 40København1871 Frederiksberg CDenmark
| | - Cora A. MacAlister
- Department of Molecular, Cellular and Developmental BiologyUniversity of Michigan1105 N. University AveAnn ArborMI48109USA
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19
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Pejchar P, Sekereš J, Novotný O, Žárský V, Potocký M. Functional analysis of phospholipase Dδ family in tobacco pollen tubes. Plant J 2020; 103:212-226. [PMID: 32064689 DOI: 10.1111/tpj.14720] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/11/2019] [Revised: 01/17/2020] [Accepted: 02/04/2020] [Indexed: 06/10/2023]
Abstract
Phosphatidic acid (PA), an important signalling and metabolic phospholipid, is predominantly localized in the subapical plasma membrane (PM) of growing pollen tubes. PA can be produced from structural phospholipids by phospholipase D (PLD), but the isoforms responsible for production of PM PA were not identified yet and their functional roles remain unknown. Following genome-wide bioinformatic analysis of the PLD family in tobacco, we focused on the pollen-overrepresented PLDδ class. Combining live-cell imaging, gene overexpression, lipid-binding and structural bioinformatics, we characterized five NtPLDδ isoforms. Distinct PLDδ isoforms preferentially localize to the cytoplasm or subapical PM. Using fluorescence recovery after photobleaching, domain deletion and swapping analyses we show that membrane-bound PLDδs are tightly bound to PM, primarily via the central catalytic domain. Overexpression analyses suggested isoform PLDδ3 as the most important member of the PLDδ subfamily active in pollen tubes. Moreover, only PLDδ3 shows significant constitutive PLD activity in vivo and, in turn, PA promotes binding of PLDδ3 to the PM. This forms a positive feedback loop leading to PA accumulation and the formation of massive PM invaginations. Tightly controlled production of PA generated by PLDδ3 at the PM is important for maintaining the balance between various membrane trafficking processes that are crucial for plant cell tip growth.
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Affiliation(s)
- Přemysl Pejchar
- Institute of Experimental Botany of the Czech Academy of Sciences, 16502, Prague 6, Czech Republic
| | - Juraj Sekereš
- Institute of Experimental Botany of the Czech Academy of Sciences, 16502, Prague 6, Czech Republic
| | - Ondřej Novotný
- Institute of Experimental Botany of the Czech Academy of Sciences, 16502, Prague 6, Czech Republic
- Department of Biochemistry and Microbiology, University of Chemistry and Technology Prague, 16628, Prague 6, Czech Republic
| | - Viktor Žárský
- Institute of Experimental Botany of the Czech Academy of Sciences, 16502, Prague 6, Czech Republic
- Department of Experimental Plant Biology, Charles University, 128 44, Prague 2, Czech Republic
| | - Martin Potocký
- Institute of Experimental Botany of the Czech Academy of Sciences, 16502, Prague 6, Czech Republic
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20
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Buschmann H. Into another dimension: how streptophyte algae gained morphological complexity. J Exp Bot 2020; 71:3279-3286. [PMID: 32270175 DOI: 10.1093/jxb/eraa181] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2020] [Accepted: 04/07/2020] [Indexed: 06/11/2023]
Abstract
Land plants with elaborated three-dimensional (3D) body plans have evolved from streptophyte algae. The streptophyte algae are known to exhibit varying degrees of morphological complexity, ranging from single-celled flagellates to branched macrophytic forms exhibiting tissue-like organization. In this review, I discuss mechanisms by which, during evolution, filamentous algae may have gained 2D and eventually 3D body plans. There are, in principle, two mechanisms by which an additional dimension may be added to an existing algal filament or cell layer: first, by tip growth-mediated branching. An example of this mechanism is the emergence and polar expansion of root hairs from land plants. The second possibility is the rotation of the cell division plane. In this case, the plane of the forthcoming cell division is rotated within the parental cell wall. This type of mechanism corresponds to the formative cell division seen in meristems of land plants. This literature review shows that of the extant streptophyte algae, the Charophyceae and Coleochaetophyceae are capable of performing both mechanisms, while the Zygnematophyceae (the actual sister to land plants) show tip growth-based branching only. I finally discuss how apical cells with two or three cutting faces, as found in mosses, may have evolved from algal ancestors.
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21
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Vissenberg K, Gonzalez N. Plant organ and tip growth. J Exp Bot 2020; 71:2363-2364. [PMID: 32324242 PMCID: PMC7178413 DOI: 10.1093/jxb/eraa163] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Affiliation(s)
- Kris Vissenberg
- Integrated Molecular Plant Physiology Research, Department of Biology, University of Antwerp, Antwerp, Belgium
- Plant Biochemistry and Biotechnology Lab, Department of Agriculture, Hellenic Mediterranean University, Heraklion, Crete, Greece
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22
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Guo J, Yang Z. Exocytosis and endocytosis: coordinating and fine-tuning the polar tip growth domain in pollen tubes. J Exp Bot 2020; 71:2428-2438. [PMID: 32173729 PMCID: PMC7178420 DOI: 10.1093/jxb/eraa134] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2019] [Accepted: 03/11/2020] [Indexed: 05/06/2023]
Abstract
Pollen tubes rapidly elongate, penetrate, and navigate through multiple female tissues to reach ovules for sperm delivery by utilizing a specialized form of polar growth known as tip growth. This process requires a battery of cellular activities differentially occurring at the apical growing region of the plasma membrane (PM), such as the differential cellular signaling involving calcium (Ca2+), phospholipids, and ROP-type Rho GTPases, fluctuation of ions and pH, exocytosis and endocytosis, and cell wall construction and remodeling. There is an emerging understanding of how at least some of these activities are coordinated and/or interconnected. The apical active ROP modulates exocytosis to the cell apex for PM and cell wall expansion differentially occurring at the tip. The differentiation of the cell wall involves at least the preferential distribution of deformable pectin polymers to the apex and non-deformable pectin polymers to the shank of pollen tubes, facilitating the apical cell expansion driven by high internal turgor pressure. Recent studies have generated inroads into how the ROP GTPase-based intracellular signaling is coordinated spatiotemporally with the external wall mechanics to maintain the tubular cell shape and how the apical cell wall mechanics are regulated to allow rapid tip growth while maintaining the cell wall integrity under the turgor pressure. Evidence suggests that exocytosis and endocytosis play crucial but distinct roles in this spatiotemporal coordination. In this review, we summarize recent advances in the regulation and coordination of the differential pectin distribution and the apical domain of active ROP by exocytosis and endocytosis in pollen tubes.
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Affiliation(s)
- Jingzhe Guo
- FAFU-UCR Joint Center for Horticultural Biology and Metabolomics, Haixia Institute of Science and Technology, Fujian Agriculture and Forestry University, Fuzhou, Fujian, China
- Department of Botany and Plant Sciences and Institute for Integrative Genome Biology, University of California, Riverside, CA, USA
| | - Zhenbiao Yang
- Department of Botany and Plant Sciences and Institute for Integrative Genome Biology, University of California, Riverside, CA, USA
- Correspondence:
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23
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Siméon A, Kridi S, Kloareg B, Hervé C. Presence of Exogenous Sulfate Is Mandatory for Tip Growth in the Brown Alga Ectocarpus subulatus. Front Plant Sci 2020; 11:1277. [PMID: 33013948 PMCID: PMC7461865 DOI: 10.3389/fpls.2020.01277] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/08/2020] [Accepted: 08/05/2020] [Indexed: 05/08/2023]
Abstract
Brown algae (Phaeophyceae) are multicellular photoautrophic organisms and the largest biomass producers in coastal regions. A variety of observations indicate that their extracellular matrix (ECM) is involved with screening of salts, development, cell fate selection, and defense responses. It is likely that these functionalities are related to its constitutive structures. The major components of the ECM of brown algae are β-glucans, alginates, and fucose-containing sulfated polysaccharides. The genus Ectocarpus comprises a wide range of species that have adapted to different environments, including isolates of Ectocarpus subulatus, a species highly resistant to low salinity. Previous studies on a freshwater strain of E. subulatus indicated that the sulfate remodeling of fucans is related to the external salt concentration. Here we show that the sulfate content of the surrounding medium is a key parameter influencing both the patterning of the alga and the occurrence of the BAM4 sulfated fucan epitope in walls of apical cells. These results indicate that sulfate uptake and incorporation in the sulfated fucans from apical cells is an essential parameter to sustain tip growth, and we discuss its influence on the architectural plasticity of Ectocarpus.
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24
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Westermann J, Streubel S, Franck CM, Lentz R, Dolan L, Boisson-Dernier A. An Evolutionarily Conserved Receptor-like Kinases Signaling Module Controls Cell Wall Integrity During Tip Growth. Curr Biol 2019; 29:3899-3908.e3. [PMID: 31679933 DOI: 10.1016/j.cub.2019.09.069] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2019] [Revised: 08/29/2019] [Accepted: 09/26/2019] [Indexed: 02/02/2023]
Abstract
Rooting cells and pollen tubes-key adaptative innovations that evolved during the colonization and subsequent radiation of plants on land-expand by tip growth. Tip growth relies on a tight coordination between the protoplast growth and the synthesis/remodeling of the external cell wall. In root hairs and pollen tubes of the seed plant Arabidopsis thaliana, cell wall integrity (CWI) mechanisms monitor this coordination through the Malectin-like receptor kinases (MLRs), such as AtANXUR1 and AtFERONIA, that act upstream of the AtMARIS PTI1-like kinase. Here, we show that rhizoid growth in the early diverging plant, Marchantia polymorpha, is also controlled by an MLR and PTI1-like signaling module. Rhizoids, root hairs, and pollen tubes respond similarly to disruption of MLR and PTI1-like encoding genes. Thus, the MLR and PTI1-like signaling module that controls CWI during tip growth is conserved between M. polymorpha and A. thaliana, suggesting that it was active in the common ancestor of land plants.
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Affiliation(s)
| | - Susanna Streubel
- Department of Plant Sciences, University of Oxford, South Parks Road, Oxford OX1 3RB, UK
| | | | - Roswitha Lentz
- University of Cologne, Biocenter, 50674 Cologne, Germany
| | - Liam Dolan
- Department of Plant Sciences, University of Oxford, South Parks Road, Oxford OX1 3RB, UK
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25
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Denninger P, Reichelt A, Schmidt VAF, Mehlhorn DG, Asseck LY, Stanley CE, Keinath NF, Evers JF, Grefen C, Grossmann G. Distinct RopGEFs Successively Drive Polarization and Outgrowth of Root Hairs. Curr Biol 2019; 29:1854-1865.e5. [PMID: 31104938 DOI: 10.1016/j.cub.2019.04.059] [Citation(s) in RCA: 57] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2019] [Revised: 04/01/2019] [Accepted: 04/23/2019] [Indexed: 11/24/2022]
Abstract
Root hairs are tubular protrusions of the root epidermis that significantly enlarge the exploitable soil volume in the rhizosphere. Trichoblasts, the cell type responsible for root hair formation, switch from cell elongation to tip growth through polarization of the growth machinery to a predefined root hair initiation domain (RHID) at the plasma membrane. The emergence of this polar domain resembles the establishment of cell polarity in other eukaryotic systems [1-3]. Rho-type GTPases of plants (ROPs) are among the first molecular determinants of the RHID [4, 5], and later play a central role in polar growth [6]. Numerous studies have elucidated mechanisms that position the RHID in the cell [7-9] or regulate ROP activity [10-18]. The molecular players that target ROPs to the RHID and initiate outgrowth, however, have not been identified. We dissected the timing of the growth machinery assembly in polarizing hair cells and found that positioning of molecular players and outgrowth are temporally separate processes that are each controlled by specific ROP guanine nucleotide exchange factors (GEFs). A functional analysis of trichoblast-specific GEFs revealed GEF3 to be required for normal ROP polarization and thus efficient root hair emergence, whereas GEF4 predominantly regulates subsequent tip growth. Ectopic expression of GEF3 induced the formation of spatially confined, ROP-recruiting domains in other cell types, demonstrating the role of GEF3 to serve as a membrane landmark during cell polarization.
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Affiliation(s)
- Philipp Denninger
- Centre for Organismal Studies (COS), Heidelberg University, Im Neuenheimer Feld 230, 69120 Heidelberg, Germany
| | - Anna Reichelt
- Centre for Organismal Studies (COS), Heidelberg University, Im Neuenheimer Feld 230, 69120 Heidelberg, Germany
| | - Vanessa A F Schmidt
- Centre for Organismal Studies (COS), Heidelberg University, Im Neuenheimer Feld 230, 69120 Heidelberg, Germany
| | - Dietmar G Mehlhorn
- Center for Plant Molecular Biology, Developmental Genetics, University of Tübingen, Auf der Morgenstelle 32, 72076 Tübingen, Germany
| | - Lisa Y Asseck
- Center for Plant Molecular Biology, Developmental Genetics, University of Tübingen, Auf der Morgenstelle 32, 72076 Tübingen, Germany
| | - Claire E Stanley
- Institute for Chemical and Bioengineering, ETH Zürich, Vladimir-Prelog-Weg 1, 8093 Zürich, Switzerland; Agroecology and Environment Research Division, Agroscope, Reckenholzstrasse 191, 8046 Zürich, Switzerland
| | - Nana F Keinath
- Centre for Organismal Studies (COS), Heidelberg University, Im Neuenheimer Feld 230, 69120 Heidelberg, Germany
| | - Jan-Felix Evers
- Centre for Organismal Studies (COS), Heidelberg University, Im Neuenheimer Feld 230, 69120 Heidelberg, Germany
| | - Christopher Grefen
- Center for Plant Molecular Biology, Developmental Genetics, University of Tübingen, Auf der Morgenstelle 32, 72076 Tübingen, Germany
| | - Guido Grossmann
- Centre for Organismal Studies (COS), Heidelberg University, Im Neuenheimer Feld 230, 69120 Heidelberg, Germany; Excellence Cluster CellNetworks, Heidelberg University, Im Neuenheimer Feld 267, 69120 Heidelberg, Germany.
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26
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Vaz Dias F, Serrazina S, Vitorino M, Marchese D, Heilmann I, Godinho M, Rodrigues M, Malhó R. A role for diacylglycerol kinase 4 in signalling crosstalk during Arabidopsis pollen tube growth. New Phytol 2019; 222:1434-1446. [PMID: 30628082 DOI: 10.1111/nph.15674] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Accepted: 12/28/2018] [Indexed: 05/29/2023]
Abstract
Diacylglycerol kinases (DGKs) play a major role in the production of phosphatidic acid (PtdOH) and were implicated in endomembrane trafficking and signalling cascades. In plants, the role of DGKs is less clear, as PtdOH seems to arise mostly from phospholipase D activity. Here, we investigated the function of the Arabidopsis gene encoding DGK4, which is highly expressed in pollen. In vitro, pollen tubes from homozygous dgk4 plants showed normal morphology, but reduced growth rate and altered stiffness and adhesion properties (revealed by atomic force microscopy). In vivo, dgk4 pollen was able to fertilize wild-type ovules, but self-pollination in dgk4 plants led to fewer seeds and shorter siliques. Phenotypic analysis revealed that the dgk4 mutation affects not only the male germ line but also the vegetative tissue. DGK4-green fluorescent protein fusion imaging revealed a cytosolic localization with a slightly higher signal in the subapical or apical region. dgk4 pollen tubes were found to exhibit perturbations in membrane recycling, and lipid analysis revealed a minor increase of PtdOH concomitant with decreased phosphatidylcholine, compared with wild-type. In vitro, DGK4 was found to exhibit kinase and guanylyl cyclase activity. Quantitative PCR data revealed downregulation of genes related to actin dynamics and phosphoinositide metabolism in mutant pollen, but upregulation of the DGK6 isoform. Altogether, these results are discussed considering a role of DGK4 in signalling cross-talk.
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Affiliation(s)
- Fernando Vaz Dias
- Faculdade de Ciências de Lisboa, BioISI, Universidade de Lisboa, 1749-016, Lisbon, Portugal
| | - Susana Serrazina
- Faculdade de Ciências de Lisboa, BioISI, Universidade de Lisboa, 1749-016, Lisbon, Portugal
| | - Miguel Vitorino
- Faculdade de Ciências de Lisboa, BioISI, Universidade de Lisboa, 1749-016, Lisbon, Portugal
| | - Dario Marchese
- Faculdade de Ciências de Lisboa, BioISI, Universidade de Lisboa, 1749-016, Lisbon, Portugal
| | - Ingo Heilmann
- Institute of Biochemistry and Biotechnology/Cellular Biochemistry, Martin-Luther-University Halle-Wittenberg, 06120, Halle (Saale), Germany
| | - Margarida Godinho
- Faculdade de Ciências de Lisboa, BioISI, Universidade de Lisboa, 1749-016, Lisbon, Portugal
| | - Mário Rodrigues
- Faculdade de Ciências de Lisboa, BioISI, Universidade de Lisboa, 1749-016, Lisbon, Portugal
| | - Rui Malhó
- Faculdade de Ciências de Lisboa, BioISI, Universidade de Lisboa, 1749-016, Lisbon, Portugal
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Li E, Cui Y, Ge FR, Chai S, Zhang WT, Feng QN, Jiang L, Li S, Zhang Y. AGC1.5 Kinase Phosphorylates RopGEFs to Control Pollen Tube Growth. Mol Plant 2018; 11:1198-1209. [PMID: 30055264 DOI: 10.1016/j.molp.2018.07.004] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2018] [Revised: 07/19/2018] [Accepted: 07/19/2018] [Indexed: 05/22/2023]
Abstract
Double fertilization in angiosperms requires the targeted delivery of immotile sperm to the eggs through pollen tubes. The polarity of tip-growing pollen tubes is maintained through dynamic association of active Rho GTPases of plants (ROP-GTP) with the apical plasma membrane. Guanine nucleotide exchange factors for ROPs (RopGEFs) catalyze the activation of ROPs and thereby affect spatiotemporal ROP signaling. Whereas RopGEFs have been found to be phosphorylated proteins, the kinases responsible for their phosphorylation in vivo and biological consequences of RopGEF phosphorylation in pollen tube growth remain unclear. We report here that the Arabidopsis AGC1.5 subfamily of cytoplasmic kinases is critical for the restricted localization of ROP-GTP during pollen tube growth. Loss of AGC1.5 and AGC1.7 functions resulted in the mistargeting of active ROPs and defective events downstream of ROP signaling in pollen tubes. AGC1.5 interacts with RopGEFs via their catalytic PRONE domain and phosphorylates RopGEFs at a conserved Ser residue of PRONE domain. Loss of AGC1.5 and AGC1.7 functions resulted in the mistargeting of RopGEFs in pollen tubes, similar to the phenotype caused by the mutation that renders RopGEFs non-phosphorylatable by AGC1.5. Collectively, our results provide mechanistic insights into the spatiotemporal activation of ROPs during the polar growth of pollen tubes.
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Affiliation(s)
- En Li
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an 271018, China
| | - Yong Cui
- School of Life Sciences, Centre for Cell and Developmental Biology and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China
| | - Fu-Rong Ge
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an 271018, China
| | - Sen Chai
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an 271018, China
| | - Wei-Tong Zhang
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an 271018, China
| | - Qiang-Nan Feng
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an 271018, China
| | - Liwen Jiang
- School of Life Sciences, Centre for Cell and Developmental Biology and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China
| | - Sha Li
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an 271018, China.
| | - Yan Zhang
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an 271018, China.
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28
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Parrotta L, Faleri C, Del Duca S, Cai G. Depletion of sucrose induces changes in the tip growth mechanism of tobacco pollen tubes. Ann Bot 2018; 122:23-43. [PMID: 29659664 PMCID: PMC6025209 DOI: 10.1093/aob/mcy043] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/03/2018] [Accepted: 03/09/2018] [Indexed: 05/24/2023]
Abstract
Background and Aims Pollen tubes are rapidly growing, photosynthetically inactive cells that need high rates of energy to support growth. Energy can derive from internal and external storage sources. The lack of carbon sources can cause various problems during pollen tube growth, which in turn could affect the reproduction of plants. Methods We analysed the effects of energy deficiency on the development of Nicotiana tabacum pollen tubes by replacing sucrose with glycerol in the growth medium. We focused on cell growth and related processes, such as metabolite composition and cell wall synthesis. Key Results We found that the lack of sucrose affects pollen germination and pollen tube length during a specific growth period. Both sugar metabolism and ATP concentration were affected by sucrose shortage when pollen tubes were grown in glycerol-based media; this was related to decreases in the concentrations of glucose, fructose and UDP-glucose. The intracellular pH and ROS levels also showed a different distribution in pollen tubes grown in sucrose-depleted media. Changes were also observed at the cell wall level, particularly in the content and distribution of two enzymes related to cell wall synthesis (sucrose synthase and callose synthase). Furthermore, both callose and newly secreted cell wall material (mainly pectins) showed an altered distribution corresponding to the lack of oscillatory growth in pollen tubes. Growth in glycerol-based media also temporarily affected the movement of generative cells and, in parallel, the deposition of callose plugs. Conclusion Pollen tubes represent an ideal model system for studying metabolic pathways during the growth of plant cells. In our study, we found evidence that glycerol, a less energetic source for cell growth than sucrose, causes critical changes in cell wall deposition. The evidence that different aspects of pollen tube growth are affected is an indication that pollen tubes adapt to metabolic stress.
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Affiliation(s)
- Luigi Parrotta
- Dipartimento Scienze della Vita, Università di Siena, Siena, Italy
| | - Claudia Faleri
- Dipartimento Scienze della Vita, Università di Siena, Siena, Italy
| | - Stefano Del Duca
- Dipartimento Scienze Biologiche, Geologiche e Ambientali, Università di Bologna, Bologna, Italy
| | - Giampiero Cai
- Dipartimento Scienze della Vita, Università di Siena, Siena, Italy
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29
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Cole RA, Peremyslov VV, Van Why S, Moussaoui I, Ketter A, Cool R, Moreno MA, Vejlupkova Z, Dolja VV, Fowler JE. A broadly conserved NERD genetically interacts with the exocyst to affect root growth and cell expansion. J Exp Bot 2018; 69:3625-3637. [PMID: 29722827 PMCID: PMC6022600 DOI: 10.1093/jxb/ery162] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2017] [Accepted: 04/24/2018] [Indexed: 05/10/2023]
Abstract
The exocyst, a conserved, octameric protein complex, helps mediate secretion at the plasma membrane, facilitating specific developmental processes that include control of root meristem size, cell elongation, and tip growth. A genetic screen for second-site enhancers in Arabidopsis identified NEW ENHANCER of ROOT DWARFISM1 (NERD1) as an exocyst interactor. Mutations in NERD1 combined with weak exocyst mutations in SEC8 and EXO70A1 result in a synergistic reduction in root growth. Alone, nerd1 alleles modestly reduce primary root growth, both by shortening the root meristem and by reducing cell elongation, but also result in a slight increase in root hair length, bulging, and rupture. NERD1 was identified molecularly as At3g51050, which encodes a transmembrane protein of unknown function that is broadly conserved throughout the Archaeplastida. A functional NERD1-GFP fusion localizes to the Golgi, in a pattern distinct from the plasma membrane-localized exocyst, arguing against a direct NERD1-exocyst interaction. Structural modeling suggests the majority of the protein is positioned in the lumen, in a β-propeller-like structure that has some similarity to proteins that bind polysaccharides. We suggest that NERD1 interacts with the exocyst indirectly, possibly affecting polysaccharides destined for the cell wall, and influencing cell wall characteristics in a developmentally distinct manner.
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Affiliation(s)
- Rex A Cole
- Department of Botany and Plant Pathology and Center for Genome Research and Biocomputing, Oregon State University, Corvallis, OR, USA
| | - Valera V Peremyslov
- Department of Botany and Plant Pathology and Center for Genome Research and Biocomputing, Oregon State University, Corvallis, OR, USA
| | - Savannah Van Why
- Department of Botany and Plant Pathology and Center for Genome Research and Biocomputing, Oregon State University, Corvallis, OR, USA
| | - Ibrahim Moussaoui
- Department of Botany and Plant Pathology and Center for Genome Research and Biocomputing, Oregon State University, Corvallis, OR, USA
| | - Ann Ketter
- Department of Botany and Plant Pathology and Center for Genome Research and Biocomputing, Oregon State University, Corvallis, OR, USA
| | - Renee Cool
- Department of Botany and Plant Pathology and Center for Genome Research and Biocomputing, Oregon State University, Corvallis, OR, USA
| | - Matthew Andres Moreno
- Department of Botany and Plant Pathology and Center for Genome Research and Biocomputing, Oregon State University, Corvallis, OR, USA
| | - Zuzana Vejlupkova
- Department of Botany and Plant Pathology and Center for Genome Research and Biocomputing, Oregon State University, Corvallis, OR, USA
| | - Valerian V Dolja
- Department of Botany and Plant Pathology and Center for Genome Research and Biocomputing, Oregon State University, Corvallis, OR, USA
| | - John E Fowler
- Department of Botany and Plant Pathology and Center for Genome Research and Biocomputing, Oregon State University, Corvallis, OR, USA
- Correspondence:
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30
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Gnana Kumar G, Chung SH, Raj Kumar T, Manthiram A. Three-Dimensional Graphene-Carbon Nanotube-Ni Hierarchical Architecture as a Polysulfide Trap for Lithium-Sulfur Batteries. ACS Appl Mater Interfaces 2018; 10:20627-20634. [PMID: 29799717 DOI: 10.1021/acsami.8b06054] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Despite their high energy density and affordable cost compared to lithium-ion (Li-ion) batteries, lithium-sulfur (Li-S) batteries still endure from slow reaction kinetics and capacity loss induced by the insulating sulfur and severe polysulfide diffusion. To address these issues, we report here nickel nanoparticles filled in vertically grown carbon nanotubes (CNTs) on graphene sheets (graphene-CNT-nickel composite (Gr-CNT-Ni)) that are coated onto a polypropylene separator as a polysulfide trap for the construction of high-loading sulfur cathodes. The hierarchical porous framework of Gr-CNT physically entraps and immobilizes the active material sulfur, while the strong chemical interaction with Ni nanoparticles in Gr-CNT-Ni inhibits polysulfide diffusion. The covalently interconnected electron conduction channels and carbon shell-confined metal active sites provide feasible paths for the continual regeneration of active material during the charge-discharge process. Benefitting from these novel morphological and structural features, the Li-S cell with the Gr-CNT-Ni as a polysulfide trap demonstrates high specific capacity and good cycle life. This work provides new avenues for synergistically combining the advantages of hierarchical porous carbon architectures and metal active sites for the development of high-performance cathodes for Li-S batteries.
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Affiliation(s)
- G Gnana Kumar
- Department of Physical Chemistry, School of Chemistry , Madurai Kamaraj University , Madurai 625021 , Tamil Nadu , India
- Materials Science and Engineering Program, Texas Materials Institute , The University of Texas at Austin , Austin , Texas 78712 , United States
| | - Sheng-Heng Chung
- Materials Science and Engineering Program, Texas Materials Institute , The University of Texas at Austin , Austin , Texas 78712 , United States
| | - T Raj Kumar
- Department of Physical Chemistry, School of Chemistry , Madurai Kamaraj University , Madurai 625021 , Tamil Nadu , India
| | - Arumugam Manthiram
- Materials Science and Engineering Program, Texas Materials Institute , The University of Texas at Austin , Austin , Texas 78712 , United States
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31
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Bascom CS Jr, Winship LJ, Bezanilla M. Simultaneous imaging and functional studies reveal a tight correlation between calcium and actin networks. Proc Natl Acad Sci U S A 2018; 115:E2869-78. [PMID: 29507239 DOI: 10.1073/pnas.1711037115] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Tip-growing cells elongate in a highly polarized manner via focused secretion of flexible cell-wall material. Calcium has been implicated as a vital factor in regulating the deposition of cell-wall material. However, deciphering the molecular and mechanistic calcium targets in vivo has remained challenging. Here, we investigated intracellular calcium dynamics in the moss Physcomitrella patens, which provides a system with an abundant source of genetically identical tip-growing cells, excellent cytology, and a large molecular genetic tool kit. To visualize calcium we used a genetically encoded cytosolic FRET probe, revealing a fluctuating tipward gradient with a complex oscillatory profile. Wavelet analysis coupled with a signal-sifting algorithm enabled the quantitative comparison of the calcium behavior in cells where growth was inhibited mechanically, pharmacologically, or genetically. We found that cells with suppressed growth have calcium oscillatory profiles with longer frequencies, suggesting that there is a feedback between the calcium gradient and growth. To investigate the mechanistic basis for this feedback we simultaneously imaged cytosolic calcium and actin, which has been shown to be essential for tip growth. We found that high cytosolic calcium promotes disassembly of a tip-focused actin spot, while low calcium promotes assembly. In support of this, abolishing the calcium gradient resulted in dramatic actin accumulation at the tip. Together these data demonstrate that tipward calcium is quantitatively linked to actin accumulation in vivo and that the moss P. patens provides a powerful system to uncover mechanistic links between calcium, actin, and growth.
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32
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Schoenaers S, Balcerowicz D, Breen G, Hill K, Zdanio M, Mouille G, Holman TJ, Oh J, Wilson MH, Nikonorova N, Vu LD, De Smet I, Swarup R, De Vos WH, Pintelon I, Adriaensen D, Grierson C, Bennett MJ, Vissenberg K. The Auxin-Regulated CrRLK1L Kinase ERULUS Controls Cell Wall Composition during Root Hair Tip Growth. Curr Biol 2018; 28:722-732.e6. [PMID: 29478854 DOI: 10.1016/j.cub.2018.01.050] [Citation(s) in RCA: 78] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2017] [Revised: 11/10/2017] [Accepted: 01/18/2018] [Indexed: 01/07/2023]
Abstract
Root hairs facilitate a plant's ability to acquire soil anchorage and nutrients. Root hair growth is regulated by the plant hormone auxin and dependent on localized synthesis, secretion, and modification of the root hair tip cell wall. However, the exact cell wall regulators in root hairs controlled by auxin have yet to be determined. In this study, we describe the characterization of ERULUS (ERU), an auxin-induced Arabidopsis receptor-like kinase, whose expression is directly regulated by ARF7 and ARF19 transcription factors. ERU belongs to the Catharanthus roseus RECEPTOR-LIKE KINASE 1-LIKE (CrRLK1L) subfamily of putative cell wall sensor proteins. Imaging of a fluorescent fusion protein revealed that ERU is localized to the apical root hair plasma membrane. ERU regulates cell wall composition in root hairs and modulates pectin dynamics through negative control of pectin methylesterase (PME) activity. Mutant eru (-/-) root hairs accumulate de-esterified homogalacturonan and exhibit aberrant pectin Ca2+-binding site oscillations and increased PME activity. Up to 80% of the eru root hair phenotype is rescued by pharmacological supplementation with a PME-inhibiting catechin extract. ERU transcription is altered in specific cell wall-related root hair mutants, suggesting that it is a target for feedback regulation. Loss of ERU alters the phosphorylation status of FERONIA and H+-ATPases 1/2, regulators of apoplastic pH. Furthermore, H+-ATPases 1/2 and ERU are differentially phosphorylated in response to auxin. We conclude that ERULUS is a key auxin-controlled regulator of cell wall composition and pectin dynamics during root hair tip growth.
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Affiliation(s)
- Sébastjen Schoenaers
- Integrated Molecular Plant Physiology Research, Biology Department, University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium
| | - Daria Balcerowicz
- Integrated Molecular Plant Physiology Research, Biology Department, University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium
| | - Gordon Breen
- School of Biological Sciences, University of Bristol, Bristol BS8 1UG, UK
| | - Kristine Hill
- Centre for Plant Integrative Biology, School of Biosciences, Sutton Bonington Campus, University of Nottingham, Loughborough LE12 5RD, UK
| | - Malgorzata Zdanio
- Integrated Molecular Plant Physiology Research, Biology Department, University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium
| | - Grégory Mouille
- Institut Jean-Pierre Bourgin, UMR1318 INRA/AgroParisTech, ERL3559 CNRS, Saclay Plant Sciences, Route de St Cyr, 78026 Versailles, France
| | - Tara J Holman
- Centre for Plant Integrative Biology, School of Biosciences, Sutton Bonington Campus, University of Nottingham, Loughborough LE12 5RD, UK
| | - Jaesung Oh
- Centre for Plant Integrative Biology, School of Biosciences, Sutton Bonington Campus, University of Nottingham, Loughborough LE12 5RD, UK
| | - Michael H Wilson
- Centre for Plant Integrative Biology, School of Biosciences, Sutton Bonington Campus, University of Nottingham, Loughborough LE12 5RD, UK
| | - Natalia Nikonorova
- Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Ghent, Belgium; Center for Plant Systems Biology, VIB, 9052 Ghent, Belgium
| | - Lam Dai Vu
- Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Ghent, Belgium; Center for Plant Systems Biology, VIB, 9052 Ghent, Belgium; VIB-UGent Center for Medical Biotechnology, VIB, Ghent, Belgium; Department of Biochemistry, Ghent University, Ghent, Belgium
| | - Ive De Smet
- Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Ghent, Belgium; Center for Plant Systems Biology, VIB, 9052 Ghent, Belgium
| | - Ranjan Swarup
- Centre for Plant Integrative Biology, School of Biosciences, Sutton Bonington Campus, University of Nottingham, Loughborough LE12 5RD, UK
| | - Winnok H De Vos
- Laboratory of Cell Biology and Histology, Department of Veterinary Sciences, University of Antwerp, Universiteitsplein 1, 2610 Wilrijk, Belgium; Cell Systems Group, Department of Molecular Biotechnology, University of Ghent, Coupure Links 653, 9000 Ghent, Belgium
| | - Isabel Pintelon
- Laboratory of Cell Biology and Histology, Department of Veterinary Sciences, University of Antwerp, Universiteitsplein 1, 2610 Wilrijk, Belgium
| | - Dirk Adriaensen
- Laboratory of Cell Biology and Histology, Department of Veterinary Sciences, University of Antwerp, Universiteitsplein 1, 2610 Wilrijk, Belgium
| | - Claire Grierson
- School of Biological Sciences, University of Bristol, Bristol BS8 1UG, UK
| | - Malcolm J Bennett
- Centre for Plant Integrative Biology, School of Biosciences, Sutton Bonington Campus, University of Nottingham, Loughborough LE12 5RD, UK
| | - Kris Vissenberg
- Integrated Molecular Plant Physiology Research, Biology Department, University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium; Plant Biochemistry & Biotechnology Lab, Department of Agriculture, Technological Educational Institute of Crete, Stavromenos PC 71410, Heraklion, Crete, Greece.
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Abstract
The eukaryotic actin cytoskeleton is a highly dynamic framework that is involved in many biological processes, such as cell growth, division, morphology, and motility. G-actin polymerizes into microfilaments that associate into bundles, patches, and networks, which, in turn, organize into higher order structures that are fundamental for the course of important physiological events. Actin rings are an example for such higher order actin entities, but this term represents an actually diverse set of subcellular structures that are involved in various processes. This review especially sheds light on a crucial type of non-constricting ring-like actin networks, and categorizes them under the term 'actin fringe'. These 'actin fringes' are visualized as highly dynamic and yet steady structures in the tip of various polarized growing cells. The present comprehensive overview compares the actin fringe characteristics of rapidly elongating pollen tubes with several related actin arrays in other cell types of diverse species. The current state of knowledge about various actin fringe functions is summarized, and the key role of this structure in the polar growth process is discussed.
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Affiliation(s)
- Octavian O H Stephan
- Department of Biology, Friedrich-Alexander University of Erlangen-Nuremberg, Erlangen, Bavaria 91058, Germany
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34
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Gilroy S. Pollen tube vs CHUKNORRIS: the action is pulsatile. J Exp Bot 2017; 68:3041-3043. [PMID: 28899082 PMCID: PMC5853307 DOI: 10.1093/jxb/erx207] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
This article comments on: Damineli SC, Portes MT, Feijo JA. 2017. Oscillatory signatures underlie growth regimes in Arabidopsis pollen tubes: computational methods to estimate tip location, periodicity, and synchronization in growing cells. Journal of Experimental Botany 68, 3267–3281.
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Affiliation(s)
- Simon Gilroy
- Department of Botany, University of Wisconsin, Birge Hall, Madison, WI, USA
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35
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Wan ZY, Zhang Y, Li S. Protein S-acyl transferase 4 controls nucleus position during root hair tip growth. Plant Signal Behav 2017; 12:e1311438. [PMID: 28368733 PMCID: PMC5437833 DOI: 10.1080/15592324.2017.1311438] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/2017] [Revised: 03/16/2017] [Accepted: 03/20/2017] [Indexed: 05/29/2023]
Abstract
Protein S-acyl transferases (PATs) play critical roles in plant developmental and environmental responses by catalyzing S-acylation of substrate proteins, most of which are involved in cellular signaling. However, only few plant PATs have been functionally characterized. We recently demonstrated that Arabidopsis PAT4 mediates root hair elongation by positively regulating the membrane association of ROP2 and actin microfilament organization. Here, we show that apex-associated re-positioning of nucleus during root hair elongation was impaired by PAT4 loss-of-function. Results presented here pose a significant question concerning the molecular machinery mediating nuclear migration during root hair growth.
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Affiliation(s)
- Zhi-Yuan Wan
- Stage Key Laboratory of Crop Biology, College of Life Science, Shandong Agricultural University, Tai'an, Shandong, China
| | - Yan Zhang
- Stage Key Laboratory of Crop Biology, College of Life Science, Shandong Agricultural University, Tai'an, Shandong, China
| | - Sha Li
- Stage Key Laboratory of Crop Biology, College of Life Science, Shandong Agricultural University, Tai'an, Shandong, China
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36
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Li S, Dong H, Pei W, Liu C, Zhang S, Sun T, Xue X, Ren H. LlFH1-mediated interaction between actin fringe and exocytic vesicles is involved in pollen tube tip growth. New Phytol 2017; 214:745-761. [PMID: 28092406 DOI: 10.1111/nph.14395] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2016] [Accepted: 11/16/2016] [Indexed: 05/15/2023]
Abstract
Pollen tube tip growth is an extreme form of polarized cell growth, which requires polarized exocytosis based on a dynamic actin cytoskeleton. However, the molecular basis for the connection between actin filaments and exocytic vesicles is unclear. Here, we identified a Lilium longiflorum pollen-specific formin (LlFH1) and found that it localized at the apical vesicles and plasma membrane (PM). Overexpression of LlFH1 induced excessive actin cables in the tube tip region, and downregulation of LlFH1 eliminated the actin fringe. Fluorescence recovery after photobleaching (FRAP) analysis revealed that LlFH1-labeled exocytic vesicles exhibited an initial accumulation at the shoulder of the apex and coincided with the leading edge of the actin fringe. Time-lapse analysis suggested that nascent actin filaments followed the emergence of the apical vesicles, implying that LlFH1 at apical vesicles could initiate actin polymerization. Biochemical assays showed that LlFH1 FH1FH2 could nucleate actin polymerization, but then capped the actin filament at the barbed end and inhibited its elongation. However, in the presence of lily profilins, LlFH1 FH1FH2 could accelerate barbed-end actin elongation. In addition, LlFH1 FH1FH2 was able to bundle actin filaments. Thus, we propose that LlFH1 and profilin coordinate the interaction between the actin fringe and exocytic vesicle trafficking during pollen tube growth of lily.
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Affiliation(s)
- Shanwei Li
- Key Laboratory of Cell Proliferation and Regulation Biology of Ministry of Education and College of Life Science, Beijing Normal University, Beijing, 100875, China
| | - Huaijian Dong
- Key Laboratory of Cell Proliferation and Regulation Biology of Ministry of Education and College of Life Science, Beijing Normal University, Beijing, 100875, China
| | - Weike Pei
- Key Laboratory of Cell Proliferation and Regulation Biology of Ministry of Education and College of Life Science, Beijing Normal University, Beijing, 100875, China
| | - Chaonan Liu
- Key Laboratory of Cell Proliferation and Regulation Biology of Ministry of Education and College of Life Science, Beijing Normal University, Beijing, 100875, China
| | - Sha Zhang
- Key Laboratory of Cell Proliferation and Regulation Biology of Ministry of Education and College of Life Science, Beijing Normal University, Beijing, 100875, China
| | - Tiantian Sun
- Key Laboratory of Cell Proliferation and Regulation Biology of Ministry of Education and College of Life Science, Beijing Normal University, Beijing, 100875, China
| | - Xiuhua Xue
- Key Laboratory of Cell Proliferation and Regulation Biology of Ministry of Education and College of Life Science, Beijing Normal University, Beijing, 100875, China
| | - Haiyun Ren
- Key Laboratory of Cell Proliferation and Regulation Biology of Ministry of Education and College of Life Science, Beijing Normal University, Beijing, 100875, China
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37
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Cho HT. An ancient transcriptional regulatory module for tip growth has been conserved throughout the vascular plant lineage. Plant Signal Behav 2017; 12:e1294300. [PMID: 28277973 PMCID: PMC5399900 DOI: 10.1080/15592324.2017.1294300] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/03/2017] [Accepted: 02/07/2017] [Indexed: 06/06/2023]
Abstract
The root hair development of vascular plants can be divided into 2 major processes, fate determination and hair morphogenesis, and the latter should be governed by the former so as to express the morphogenetic toolkits in a root hair-specific manner. Vascular plants, depending on taxa, show different fate-determining mechanisms for hair cell/non-hair cell fates, which leads to a question whether the downstream mophogenetic regulatory module is diverged accordingly to the upstream fate determiners or not. Our study demonstrates that the module of a transcription factor and a root hair-specific cis-element (RHE) for root hair-specific expression of morphogenetic toolkit genes is conserved in spite of different fate-determing mechanisms.
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Affiliation(s)
- Hyung-Taeg Cho
- Department of Biological Sciences, Seoul National University, Seoul, South Korea
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38
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Grebnev G, Ntefidou M, Kost B. Secretion and Endocytosis in Pollen Tubes: Models of Tip Growth in the Spot Light. Front Plant Sci 2017; 8:154. [PMID: 28224002 PMCID: PMC5293803 DOI: 10.3389/fpls.2017.00154] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2016] [Accepted: 01/25/2017] [Indexed: 05/18/2023]
Abstract
Pollen tube tip growth is a widely used model ideally suited to study cellular processes underlying polarized cell expansion. Local secretion supplying material for plasma membrane (PM) and cell wall extension is essential for this process. Cell wall biogenesis requires fusion of secretory vesicles with the PM at an about 10× higher rate than PM extension. Excess material is therefore incorporated into the PM, which needs to be reinternalized through endocytosis. The classical model of tip growth proposes that exocytosis occurs at the apex and that newly incorporated PM material is transported to adjacent lateral regions, where excess material is endocytically recycled. This model was recently challenged based on studies indicating that lateral exocytosis may be balanced by apical endocytosis. This review provides an overview of published data pertaining to exocytosis, endocytosis and vesicular trafficking in pollen tubes. Its key aim is to present classical and alternative models of tip growth in the light of available experimental data. By necessity, the review focusses on pollen tubes of angiosperm models (Nicotiana tabacum, Arabidopsis, Lilium longiflorum), which have been studied far more extensively and grow much faster than structurally strikingly different gymnosperm pollen tubes. Only major transport pathways are considered, which substantially contribute to the mass-flow of membrane material at the pollen tube tip. Growth oscillation, which may be displayed in particular by fast-growing pollen tubes, are not discussed as their influence on the spatial organization of apical membrane traffic is not understood.
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Affiliation(s)
| | | | - Benedikt Kost
- Cell Biology Division, Department of Biology, University of Erlangen-NurembergErlangen, Germany
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Schoenaers S, Balcerowicz D, Costa A, Vissenberg K. The Kinase ERULUS Controls Pollen Tube Targeting and Growth in Arabidopsis thaliana. Front Plant Sci 2017; 8:1942. [PMID: 29184563 PMCID: PMC5694544 DOI: 10.3389/fpls.2017.01942] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2017] [Accepted: 10/27/2017] [Indexed: 05/09/2023]
Abstract
In this paper, we describe the role of the receptor-like kinase ERULUS (ERU) in PT growth of Arabidopsis thaliana. In silico analysis and transcriptional reporter lines revealed that ERU is only expressed in pollen and root hairs (RHs), making it a tip growth-specific kinase. Deviations from Mendelian inheritance were observed in the offspring of self-pollinated heterozygous eru plants. We found that in vivo eru PT targeting was disturbed, providing a possible explanation for the observed decrease in eru fertilization competitiveness. Extracellular calcium perception and intracellular calcium dynamics lie at the basis of in vivo pollen tube (PT) tip growth and guidance. In vitro, ERU loss-of-function lines displayed no obvious PT phenotype, unless grown on low extracellular calcium ([Ca2+]ext) medium. When grown at 12 the normal [Ca2+]ext, eru PTs grew 37% slower relative to WT PTs. Visualization of cytoplasmic [Ca2+]cyt oscillations using the Yellow Cameleon 3.6 (YC3.6) calcium sensor showed that, unlike in WT PTs, eru apical [Ca2+]cyt oscillations occur at a lower frequency when grown at lower [Ca2+]ext, consistent with the observed reduced growth velocity. Our results show that the tip growth-specific kinase ERULUS is involved in regulating Ca2+-dependent PT growth, and most importantly, fertilization efficiency through successful PT targeting to the ovules.
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Affiliation(s)
- Sébastjen Schoenaers
- Integrated Molecular Plant Physiology Research, University of Antwerp, Antwerp, Belgium
| | - Daria Balcerowicz
- Integrated Molecular Plant Physiology Research, University of Antwerp, Antwerp, Belgium
| | - Alex Costa
- Department of Biosciences, University of Milan, Milan, Italy
- Institute of Biophysics, Consiglio Nazionale delle Ricerche, Milan, Italy
| | - Kris Vissenberg
- Integrated Molecular Plant Physiology Research, University of Antwerp, Antwerp, Belgium
- Plant Biochemistry and Biotechnology Lab, Technological Educational Institute of Crete: University of Applied Sciences, Crete, Greece
- *Correspondence: Kris Vissenberg,
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Winship LJ, Rounds C, Hepler PK. Perturbation Analysis of Calcium, Alkalinity and Secretion during Growth of Lily Pollen Tubes. Plants (Basel) 2016; 6:plants6010003. [PMID: 28042810 PMCID: PMC5371762 DOI: 10.3390/plants6010003] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/31/2016] [Revised: 12/24/2016] [Accepted: 12/26/2016] [Indexed: 01/07/2023]
Abstract
Pollen tubes grow by spatially and temporally regulated expansion of new material secreted into the cell wall at the tip of the tube. A complex web of interactions among cellular components, ions and small molecule provides dynamic control of localized expansion and secretion. Cross-correlation studies on oscillating lily (Lilium formosanum Wallace) pollen tubes showed that an increase in intracellular calcium follows an increase in growth, whereas the increase in the alkaline band and in secretion both anticipate the increase in growth rate. Calcium, as a follower, is unlikely to be a stimulator of growth, whereas the alkaline band, as a leader, may be an activator. To gain further insight herein we reversibly inhibited growth with potassium cyanide (KCN) and followed the re-establishment of calcium, pH and secretion patterns as growth resumed. While KCN markedly slows growth and causes the associated gradients of calcium and pH to sharply decline, its removal allows growth and vital processes to fully recover. The calcium gradient reappears before growth restarts; however, it is preceded by both the alkaline band and secretion, in which the alkaline band is slightly advanced over secretion. Thus the pH gradient, rather than the tip-focused calcium gradient, may regulate pollen tube growth.
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Affiliation(s)
| | - Caleb Rounds
- Biology Department, University of Massachusetts, Amherst, MA 01003, USA.
| | - Peter K Hepler
- Biology Department, University of Massachusetts, Amherst, MA 01003, USA.
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Honkanen S, Jones VAS, Morieri G, Champion C, Hetherington AJ, Kelly S, Proust H, Saint-Marcoux D, Prescott H, Dolan L. The Mechanism Forming the Cell Surface of Tip-Growing Rooting Cells Is Conserved among Land Plants. Curr Biol 2016; 26:3238-3244. [PMID: 27866889 PMCID: PMC5154754 DOI: 10.1016/j.cub.2016.09.062] [Citation(s) in RCA: 76] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2016] [Revised: 09/26/2016] [Accepted: 09/29/2016] [Indexed: 12/01/2022]
Abstract
To discover mechanisms that controlled the growth of the rooting system in the earliest land plants, we identified genes that control the development of rhizoids in the liverwort Marchantia polymorpha. 336,000 T-DNA transformed lines were screened for mutants with defects in rhizoid growth, and a de novo genome assembly was generated to identify the mutant genes. We report the identification of 33 genes required for rhizoid growth, of which 6 had not previously been functionally characterized in green plants. We demonstrate that members of the same orthogroup are active in cell wall synthesis, cell wall integrity sensing, and vesicle trafficking during M. polymorpha rhizoid and Arabidopsis thaliana root hair growth. This indicates that the mechanism for constructing the cell surface of tip-growing rooting cells is conserved among land plants and was active in the earliest land plants that existed sometime more than 470 million years ago [1, 2]. 336,000 T-DNA lines and a genome assembly were generated in Marchantia polymorpha 33 genes required for rhizoid growth were identified Six of the 33 genes were functionally characterized in plants for the first time Genes belonging to these orthogroups were active in the first land plant roots
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Affiliation(s)
- Suvi Honkanen
- Department of Plant Sciences, University of Oxford, South Parks Road, Oxford, OX1 3RB, UK
| | - Victor A S Jones
- Department of Plant Sciences, University of Oxford, South Parks Road, Oxford, OX1 3RB, UK
| | - Giulia Morieri
- Department of Plant Sciences, University of Oxford, South Parks Road, Oxford, OX1 3RB, UK
| | - Clement Champion
- Department of Plant Sciences, University of Oxford, South Parks Road, Oxford, OX1 3RB, UK
| | | | - Steve Kelly
- Department of Plant Sciences, University of Oxford, South Parks Road, Oxford, OX1 3RB, UK
| | - Hélène Proust
- Department of Plant Sciences, University of Oxford, South Parks Road, Oxford, OX1 3RB, UK
| | - Denis Saint-Marcoux
- Department of Plant Sciences, University of Oxford, South Parks Road, Oxford, OX1 3RB, UK
| | - Helen Prescott
- Department of Plant Sciences, University of Oxford, South Parks Road, Oxford, OX1 3RB, UK
| | - Liam Dolan
- Department of Plant Sciences, University of Oxford, South Parks Road, Oxford, OX1 3RB, UK.
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Goldenbogen B, Giese W, Hemmen M, Uhlendorf J, Herrmann A, Klipp E. Dynamics of cell wall elasticity pattern shapes the cell during yeast mating morphogenesis. Open Biol 2016; 6:160136. [PMID: 27605377 PMCID: PMC5043577 DOI: 10.1098/rsob.160136] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2016] [Accepted: 08/08/2016] [Indexed: 12/17/2022] Open
Abstract
The cell wall defines cell shape and maintains integrity of fungi and plants. When exposed to mating pheromone, Saccharomyces cerevisiae grows a mating projection and alters in morphology from spherical to shmoo form. Although structural and compositional alterations of the cell wall accompany shape transitions, their impact on cell wall elasticity is unknown. In a combined theoretical and experimental approach using finite-element modelling and atomic force microscopy (AFM), we investigated the influence of spatially and temporally varying material properties on mating morphogenesis. Time-resolved elasticity maps of shmooing yeast acquired with AFM in vivo revealed distinct patterns, with soft material at the emerging mating projection and stiff material at the tip. The observed cell wall softening in the protrusion region is necessary for the formation of the characteristic shmoo shape, and results in wider and longer mating projections. The approach is generally applicable to tip-growing fungi and plants cells.
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Affiliation(s)
- Björn Goldenbogen
- Theoretical Biophysics, Institute of Biology, Humboldt-Universität zu Berlin, Invalidenstraße 42, 10115 Berlin, Germany
| | - Wolfgang Giese
- Theoretical Biophysics, Institute of Biology, Humboldt-Universität zu Berlin, Invalidenstraße 42, 10115 Berlin, Germany
| | - Marie Hemmen
- Theoretical Biophysics, Institute of Biology, Humboldt-Universität zu Berlin, Invalidenstraße 42, 10115 Berlin, Germany
| | - Jannis Uhlendorf
- Theoretical Biophysics, Institute of Biology, Humboldt-Universität zu Berlin, Invalidenstraße 42, 10115 Berlin, Germany
| | - Andreas Herrmann
- Molecular Biophysics, Institute of Biology, Humboldt-Universität zu Berlin, Invalidenstraße 42, 10115 Berlin, Germany
| | - Edda Klipp
- Theoretical Biophysics, Institute of Biology, Humboldt-Universität zu Berlin, Invalidenstraße 42, 10115 Berlin, Germany
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Ortiz-Ramírez C, Hernandez-Coronado M, Thamm A, Catarino B, Wang M, Dolan L, Feijó JA, Becker JD. A Transcriptome Atlas of Physcomitrella patens Provides Insights into the Evolution and Development of Land Plants. Mol Plant 2016; 9:205-220. [PMID: 26687813 DOI: 10.1016/j.molp.2015.12.002] [Citation(s) in RCA: 124] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2015] [Revised: 10/28/2015] [Accepted: 12/01/2015] [Indexed: 05/08/2023]
Abstract
Identifying the genetic mechanisms that underpin the evolution of new organ and tissue systems is an aim of evolutionary developmental biology. Comparative functional genetic studies between angiosperms and bryophytes can define those genetic changes that were responsible for developmental innovations. Here, we report the generation of a transcriptome atlas covering most phases in the life cycle of the model bryophyte Physcomitrella patens, including detailed sporophyte developmental progression. We identified a comprehensive set of sporophyte-specific transcription factors, and found that many of these genes have homologs in angiosperms that function in developmental processes such as flowering and shoot branching. Deletion of the PpTCP5 transcription factor results in development of supernumerary sporangia attached to a single seta, suggesting that it negatively regulates branching in the moss sporophyte. Given that TCP genes repress branching in angiosperms, we suggest that this activity is ancient. Finally, comparison of P. patens and Arabidopsis thaliana transcriptomes led us to the identification of a conserved core of transcription factors expressed in tip-growing cells. We identified modifications in the expression patterns of these genes that could account for developmental differences between P. patens tip-growing cells and A. thaliana pollen tubes and root hairs.
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Affiliation(s)
- Carlos Ortiz-Ramírez
- Instituto Gulbenkian de Ciência, Rua da Quinta Grande 6, 2780-156 Oeiras, Portugal
| | | | - Anna Thamm
- Instituto Gulbenkian de Ciência, Rua da Quinta Grande 6, 2780-156 Oeiras, Portugal
| | - Bruno Catarino
- Department of Plant Sciences, University of Oxford, South Parks Road, Oxford OX1 3RB, UK
| | - Mingyi Wang
- Division of Plant Biology, The Samuel Roberts Noble Foundation, Ardmore, OK 73401, USA
| | - Liam Dolan
- Department of Plant Sciences, University of Oxford, South Parks Road, Oxford OX1 3RB, UK
| | - José A Feijó
- Instituto Gulbenkian de Ciência, Rua da Quinta Grande 6, 2780-156 Oeiras, Portugal; Department of Cell Biology and Molecular Genetics, University of Maryland, 0118 BioScience Research Building, College Park, MD 20742-5815, USA
| | - Jörg D Becker
- Instituto Gulbenkian de Ciência, Rua da Quinta Grande 6, 2780-156 Oeiras, Portugal.
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MacAlister CA, Ortiz-Ramírez C, Becker JD, Feijó JA, Lippman ZB. Hydroxyproline O-arabinosyltransferase mutants oppositely alter tip growth in Arabidopsis thaliana and Physcomitrella patens. Plant J 2016; 85:193-208. [PMID: 26577059 PMCID: PMC4738400 DOI: 10.1111/tpj.13079] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2015] [Revised: 09/17/2015] [Accepted: 11/03/2015] [Indexed: 05/20/2023]
Abstract
Hydroxyproline O-arabinosyltransferases (HPATs) are members of a small, deeply conserved family of plant-specific glycosyltransferases that add arabinose sugars to diverse proteins including cell wall-associated extensins and small signaling peptides. Recent genetic studies in flowering plants suggest that different HPAT homologs have been co-opted to function in diverse species-specific developmental contexts. However, nothing is known about the roles of HPATs in basal plants. We show that complete loss of HPAT function in Arabidopsis thaliana and the moss Physcomitrella patens results in a shared defect in gametophytic tip cell growth. Arabidopsis hpat1/2/3 triple knockout mutants suffer from a strong male sterility defect as a consequence of pollen tubes that fail to fully elongate following pollination. Knocking out the two HPAT genes of Physcomitrella results in larger multicellular filamentous networks due to increased elongation of protonemal tip cells. Physcomitrella hpat mutants lack cell-wall associated hydroxyproline arabinosides and can be rescued with exogenous cellulose, while global expression profiling shows that cell wall-associated genes are severely misexpressed, implicating a defect in cell wall formation during tip growth. Our findings point to a major role for HPATs in influencing cell elongation during tip growth in plants.
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Affiliation(s)
| | | | - Jörg D Becker
- Instituto Gulbenkian de Ciência, P-2780-156, Oeiras, Portugal
| | - José A Feijó
- Instituto Gulbenkian de Ciência, P-2780-156, Oeiras, Portugal
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD, 20742-5815, USA
| | - Zachary B Lippman
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, 11746, USA
- Watson School of Biological Sciences, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11746, USA
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Sun J, Eklund DM, Montes-Rodriguez A, Kost B. In vivo Rac/Rop localization as well as interaction with RhoGAP and RhoGDI in tobacco pollen tubes: analysis by low-level expression of fluorescent fusion proteins and bimolecular fluorescence complementation. Plant J 2015; 84:83-98. [PMID: 26252733 DOI: 10.1111/tpj.12961] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2015] [Revised: 07/25/2015] [Accepted: 07/29/2015] [Indexed: 05/29/2023]
Abstract
Polarized Rac/Rop GTPase signaling plays a key role in polar cell growth, which is essential for plant morphogenesis. The molecular and cellular mechanisms responsible for the polarization of Rac/Rop signaling during polar cell growth are only partially understood. Mutant variants of Rac/Rop GTPases lacking specific functions are important tools to investigate these mechanisms, and have been employed to develop a model suggesting that RhoGAP (GTPase activating protein) and RhoGDI (Guanine Nucleotide Dissociation Inhibitor) mediated recycling of Rac/Rop GTPases maintains apical polarization of Rac/Rop activity in pollen tubes, which elongate by 'tip growth' (an extreme form of polar cell growth). Despite the importance of these mutant variants for Rac/Rop functional characterization, their distinct intracellular distributions have not been thoroughly comparatively and quantitatively analyzed. Furthermore, support for the proposed RhoGAP and RhoGDI functions in apical polarization of Rac/Rop activity based on the analysis of in vivo interactions between these proteins and Rac/Rop GTPases has been missing. Here, extensive fluorescent protein tagging and bimolecular fluorescence complementation (BiFC) analyses are described of the intracellular distributions of wild type and mutant variants of the tobacco pollen tube Rac/Rop GTPase Nt-Rac5, as well as of interactions of these Nt-Rac5 variants with RhoGAP and RhoGDI proteins, in normally growing transiently transformed pollen tubes. Presented results substantially enhance our understanding of apical dynamics of pollen tube Rac/Rop signaling proteins, confirm previously proposed RhoGAP and RhoGDI functions in Rac/Rop polarization and provide important technical insights facilitating future in vivo protein localization and BiFC experiments in pollen tubes.
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Affiliation(s)
- Jia Sun
- Department of Plant Biology, Swedish University of Agricultural Sciences, Box 7080, SE-750 07, Uppsala, Sweden
| | - D Magnus Eklund
- Department of Plant Biology, Swedish University of Agricultural Sciences, Box 7080, SE-750 07, Uppsala, Sweden
| | | | - Benedikt Kost
- Cell Biology, Department of Biology, University of Erlangen-Nuremberg, 91058, Erlangen, Germany
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Safiarian MJ, Pertl-Obermeyer H, Lughofer P, Hude R, Bertl A, Obermeyer G. Lost in traffic? The K(+) channel of lily pollen, LilKT1, is detected at the endomembranes inside yeast cells, tobacco leaves, and lily pollen. Front Plant Sci 2015; 6:47. [PMID: 25713578 PMCID: PMC4322604 DOI: 10.3389/fpls.2015.00047] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2014] [Accepted: 01/16/2015] [Indexed: 05/26/2023]
Abstract
Fertilization in plants relies on fast growth of pollen tubes through the style tissue toward the ovules. This polarized growth depends on influx of ions and water to increase the tube's volume. K(+) inward rectifying channels were detected in many pollen species, with one identified in Arabidopsis. Here, an Arabidopsis AKT1-like channel (LilKT1) was identified from Lilium longiflorum pollen. Complementation of K(+) uptake deficient yeast mutants was only successful when the entire LilKT1 C-terminus was replaced by the AKT1 C-terminus. No signals were observed in the plasma membrane (PM) of pollen tubes after expression of fluorescence-tagged LilKT1 nor were any LilKT1-derived peptides detectable in the pollen PM by mass spectrometry analysis. In contrast, fluorescent LilKT1 partly co-localized with the lily PM H(+) ATPase LilHA2 in the PM of tobacco leaf cells, but exhibited a punctual fluorescence pattern and also sub-plasma membrane localization. Thus, incorporation of LilKT1 into the pollen PM seems tighter controlled than in other cells with still unknown trafficking signals in LilKT1's C-terminus, resulting in channel densities below detection limits. This highly controlled incorporation might have physiological reasons: an uncontrolled number of K(+) inward channels in the pollen PM will give an increased water influx due to the raising cytosolic K(+) concentration, and finally, causing the tube to burst.
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Affiliation(s)
- Minou J. Safiarian
- Molecular Plant Biophysics and Biochemistry, Department of Molecular Biology, University of SalzburgSalzburg, Austria
| | - Heidi Pertl-Obermeyer
- Molecular Plant Biophysics and Biochemistry, Department of Molecular Biology, University of SalzburgSalzburg, Austria
- Plant Systems Biology, University of HohenheimStuttgart, Germany
| | - Peter Lughofer
- Molecular Plant Biophysics and Biochemistry, Department of Molecular Biology, University of SalzburgSalzburg, Austria
| | - Rene Hude
- Molecular Plant Biophysics and Biochemistry, Department of Molecular Biology, University of SalzburgSalzburg, Austria
| | - Adam Bertl
- Yeast Membrane Biology, Department of Biology, Darmstadt University of TechnologyDarmstadt, Germany
| | - Gerhard Obermeyer
- Molecular Plant Biophysics and Biochemistry, Department of Molecular Biology, University of SalzburgSalzburg, Austria
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Cai G, Parrotta L, Cresti M. Organelle trafficking, the cytoskeleton, and pollen tube growth. J Integr Plant Biol 2015; 57:63-78. [PMID: 25263392 DOI: 10.1111/jipb.12289] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2014] [Accepted: 09/23/2014] [Indexed: 06/03/2023]
Abstract
The pollen tube is fundamental for the reproduction of seed plants. Characteristically, it grows relatively quickly and uni-directionally ("polarized growth") to extend the male gametophyte to reach the female gametophyte. The pollen tube forms a channel through which the sperm cells move so that they can reach their targets in the ovule. To grow quickly and directionally, the pollen tube requires an intense movement of organelles and vesicles that allows the cell's contents to be distributed to sustain the growth rate. While the various organelles distribute more or less uniformly within the pollen tube, Golgi-released secretory vesicles accumulate massively at the pollen tube apex, that is, the growing region. This intense movement of organelles and vesicles is dependent on the dynamics of the cytoskeleton, which reorganizes differentially in response to external signals and coordinates membrane trafficking with the growth rate of pollen tubes.
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Affiliation(s)
- Giampiero Cai
- Department of Life Sciences, University of Siena, Siena, 53100, Italy
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Malhó R, Serrazina S, Saavedra L, Dias FV, Ul-Rehman R. Ion and lipid signaling in apical growth-a dynamic machinery responding to extracellular cues. Front Plant Sci 2015; 6:816. [PMID: 26500662 PMCID: PMC4594336 DOI: 10.3389/fpls.2015.00816] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2015] [Accepted: 09/18/2015] [Indexed: 05/07/2023]
Abstract
Apical cell growth seems to have independently evolved throughout the major lineages of life. To a certain extent, so does our body of knowledge on the mechanisms regulating this morphogenetic process. Studies on pollen tubes, root hairs, rhizoids, fungal hyphae, even nerve cells, have highlighted tissue and cell specificities but also common regulatory characteristics (e.g., ions, proteins, phospholipids) that our focused research sometimes failed to grasp. The working hypothesis to test how apical cell growth is established and maintained have thus been shaped by the model organism under study and the type of methods used to study them. The current picture is one of a dynamic and adaptative process, based on a spatial segregation of components that network to achieve growth and respond to environmental (extracellular) cues. Here, we explore some examples of our live imaging research, namely on cyclic nucleotide gated ion channels, lipid kinases and syntaxins involved in exocytosis. We discuss how their spatial distribution, activity and concentration suggest that the players regulating apical cell growth may display more mobility than previously thought. Furthermore, we speculate on the implications of such perspective in our understanding of the mechanisms regulating apical cell growth and their responses to extracellular cues.
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Affiliation(s)
- Rui Malhó
- *Correspondence: Rui Malhó and Reiaz Ul-Rehman, BioISI – Biosystems & Integrative Sciences Institute, Faculdade de Ciências, Universidade de Lisboa, Campo Grande, 1749-016 Lisboa, Portugal, ,
| | | | - Laura Saavedra
- †Present address: Laura Saavedra, Cátedra de Fisiología Vegetal, Facultad de Ciencias Exactas, Físicas y Naturales, Universidad Nacional de Córdoba, Córdoba, Argentina; Reiaz Ul-Rehman, Department of Bioresources, University of Kashmir, Hazratbal, Srinagar 190006, India
| | | | - Reiaz Ul-Rehman
- *Correspondence: Rui Malhó and Reiaz Ul-Rehman, BioISI – Biosystems & Integrative Sciences Institute, Faculdade de Ciências, Universidade de Lisboa, Campo Grande, 1749-016 Lisboa, Portugal, ,
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Kwon T, Sparks JA, Nakashima J, Allen SN, Tang Y, Blancaflor EB. Transcriptional response of Arabidopsis seedlings during spaceflight reveals peroxidase and cell wall remodeling genes associated with root hair development. Am J Bot 2015; 102:21-35. [PMID: 25587145 DOI: 10.3732/ajb.1400458] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
UNLABELLED • PREMISE OF THE STUDY Plants will be an important component of advanced life support systems during space exploration missions. Therefore, understanding their biology in the spacecraft environment will be essential before they can be used for such systems.• METHODS Seedlings of Arabidopsis thaliana were grown for 2 wk in the Biological Research in Canisters (BRIC) hardware on board the second to the last mission of the space shuttle Discovery (STS-131). Transcript profiles between ground controls and space-grown seedlings were compared using stringent selection criteria.• KEY RESULTS Expression of transcripts associated with oxidative stress and cell wall remodeling was repressed in microgravity. These downregulated genes were previously shown to be enriched in root hairs consistent with seedling phenotypes observed in space. Mutations in genes that were downregulated in microgravity, including two uncharacterized root hair-expressed class III peroxidase genes (PRX44 and PRX57), led to defective polar root hair growth on Earth. PRX44 and PRX57 mutants had ruptured root hairs, which is a typical phenotype of tip-growing cells with defective cell walls and those subjected to stress.• CONCLUSIONS Long-term exposure to microgravity negatively impacts tip growth by repressing expression of genes essential for normal root hair development. Whereas changes in peroxidase gene expression leading to reduced root hair growth in space are actin-independent, root hair development modulated by phosphoinositides could be dependent on the actin cytoskeleton. These results have profound implications for plant adaptation to microgravity given the importance of tip growing cells such as root hairs for efficient nutrient capture.
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Affiliation(s)
- Taegun Kwon
- Plant Biology Division, The Samuel Roberts Noble Foundation, 2510 Sam Noble Parkway, Ardmore, Oklahoma 73401 USA
| | - J Alan Sparks
- Plant Biology Division, The Samuel Roberts Noble Foundation, 2510 Sam Noble Parkway, Ardmore, Oklahoma 73401 USA
| | - Jin Nakashima
- Plant Biology Division, The Samuel Roberts Noble Foundation, 2510 Sam Noble Parkway, Ardmore, Oklahoma 73401 USA
| | - Stacy N Allen
- Plant Biology Division, The Samuel Roberts Noble Foundation, 2510 Sam Noble Parkway, Ardmore, Oklahoma 73401 USA
| | - Yuhong Tang
- Plant Biology Division, The Samuel Roberts Noble Foundation, 2510 Sam Noble Parkway, Ardmore, Oklahoma 73401 USA
| | - Elison B Blancaflor
- Plant Biology Division, The Samuel Roberts Noble Foundation, 2510 Sam Noble Parkway, Ardmore, Oklahoma 73401 USA
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Larson ER, Domozych DS, Tierney ML. SNARE VTI13 plays a unique role in endosomal trafficking pathways associated with the vacuole and is essential for cell wall organization and root hair growth in arabidopsis. Ann Bot 2014; 114:1147-59. [PMID: 24737717 PMCID: PMC4195547 DOI: 10.1093/aob/mcu041] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
BACKGROUND AND AIMS Root hairs are responsible for water and nutrient uptake from the soil and their growth is responsive to biotic and abiotic changes in their environment. Root hair expansion is a polarized process requiring secretory and endosomal pathways that deliver and recycle plasma membrane and cell wall material to the growing root hair tip. In this paper, the role of VTI13 (AT3G29100), a member of the VTI vesicular soluble NSF attachment receptor (SNARE) gene family in Arabidopsis thaliana, in root hair growth is described. METHODS Genetic analysis and complementation of the vti13 root hair phenotypes of Arabidopsis thaliana were first used to assess the role of VTI13 in root hair growth. Transgenic lines expressing a green fluorescent protein (GFP)-VTI13 construct were used to characterize the intracellular localization of VTI13 in root hairs using confocal microscopy and immunotransmission electron microscopy. KEY RESULTS VTI13 was characterized and genetic analysis used to show that its function is required for root hair growth. Expression of a GFP-VTI13 fusion in the vti13 mutant background was shown to complement the vti13 root hair phenotype. GFP-VTI13 localized to both the vacuole membrane and a mobile endosomal compartment. The function of VTI13 was also required for the localization of SYP41 to the trans-Golgi network. Immunohistochemical analysis indicated that cell wall organization is altered in vti13 root hairs and root epidermal cells. CONCLUSIONS These results show that VTI13 plays a unique role in endosomal trafficking pathways associated with the vacuole within root hairs and is essential for the maintenance of cell wall organization and root hair growth in arabidopsis.
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Affiliation(s)
- Emily R Larson
- Cellular, Molecular and Biomedical Science Program Institute of Molecular Cell and Systems Biology, University of Glasgow College of Medical, Veterinary & Life Sciences, Glasgow G12 8QQ, UK
| | - David S Domozych
- Department of Biology, Skidmore College, Saratoga Springs, NY, USA
| | - Mary L Tierney
- Cellular, Molecular and Biomedical Science Program Department of Plant Biology, University of Vermont, Burlington, VT, USA
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