51
|
Ischebeck T, Seiler S, Heilmann I. At the poles across kingdoms: phosphoinositides and polar tip growth. PROTOPLASMA 2010; 240:13-31. [PMID: 20091065 PMCID: PMC2841259 DOI: 10.1007/s00709-009-0093-0] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2009] [Accepted: 11/20/2009] [Indexed: 05/20/2023]
Abstract
Phosphoinositides (PIs) are minor, but essential phospholipid constituents of eukaryotic membranes, and are involved in the regulation of various physiological processes. Recent genetic and cell biological advances indicate that PIs play important roles in the control of polar tip growth in plant cells. In root hairs and pollen tubes, PIs control directional membrane trafficking required for the delivery of cell wall material and membrane area to the growing tip. So far, the exact mechanisms by which PIs control polarity and tip growth are unresolved. However, data gained from the analysis of plant, fungal and animal systems implicate PIs in the control of cytoskeletal dynamics, ion channel activity as well as vesicle trafficking. The present review aims at giving an overview of PI roles in eukaryotic cells with a special focus on functions pertaining to the control of cell polarity. Comparative screening of plant and fungal genomes suggests diversification of the PI system with increasing organismic complexity. The evolutionary conservation of the PI system among eukaryotic cells suggests a role for PIs in tip growing cells in models where PIs so far have not been a focus of attention, such as fungal hyphae.
Collapse
Affiliation(s)
- Till Ischebeck
- Department of Plant Biochemistry, Georg-August-University Göttingen, Justus-von-Liebig-Weg 11, 37077 Göttingen, Germany
| | - Stephan Seiler
- Department of Microbiology and Genetics; and DFG Research Center Molecular Physiology of the Brain (CMPB), Georg-August-University Göttingen, Grisebachstraße 8, 37077 Göttingen, Germany
| | - Ingo Heilmann
- Department of Plant Biochemistry, Georg-August-University Göttingen, Justus-von-Liebig-Weg 11, 37077 Göttingen, Germany
| |
Collapse
|
52
|
Stewman SF, Jones-Rhoades M, Bhimalapuram P, Tchernookov M, Preuss D, Dinner AR. Mechanistic insights from a quantitative analysis of pollen tube guidance. BMC PLANT BIOLOGY 2010; 10:32. [PMID: 20170550 PMCID: PMC2844068 DOI: 10.1186/1471-2229-10-32] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/2009] [Accepted: 02/22/2010] [Indexed: 05/06/2023]
Abstract
BACKGROUND Plant biologists have long speculated about the mechanisms that guide pollen tubes to ovules. Although there is now evidence that ovules emit a diffusible attractant, little is known about how this attractant mediates interactions between the pollen tube and the ovules. RESULTS We employ a semi-in vitro assay, in which ovules dissected from Arabidopsis thaliana are arranged around a cut style on artificial medium, to elucidate how ovules release the attractant and how pollen tubes respond to it. Analysis of microscopy images of the semi-in vitro system shows that pollen tubes are more attracted to ovules that are incubated on the medium for longer times before pollen tubes emerge from the cut style. The responses of tubes are consistent with their sensing a gradient of an attractant at 100-150 mum, farther than previously reported. Our microscopy images also show that pollen tubes slow their growth near the micropyles of functional ovules with a spatial range that depends on ovule incubation time. CONCLUSIONS We propose a stochastic model that captures these dynamics. In the model, a pollen tube senses a difference in the fraction of receptors bound to an attractant and changes its direction of growth in response; the attractant is continuously released from ovules and spreads isotropically on the medium. The model suggests that the observed slowing greatly enhances the ability of pollen tubes to successfully target ovules. The relation of the results to guidance in vivo is discussed.
Collapse
Affiliation(s)
- Shannon F Stewman
- Department of Chemistry, The University of Chicago, 929 E 57th St, Chicago, IL 60637, USA
- James Franck Institute, The University of Chicago, 929 E 57th St, Chicago, IL 60637, USA
- Current address: Department of Physiology and Biophysics, Albert Einstein College of Medicine of Yeshiva University, Jack and Pearl Resnick Campus, 1300 Morris Park Ave, Bronx, NY, 10461, USA
| | | | - Prabhakar Bhimalapuram
- International Institute of Information Technology, Gachibowli, Hyderabad 500 032, Andhra Pradesh, India
| | - Martin Tchernookov
- James Franck Institute, The University of Chicago, 929 E 57th St, Chicago, IL 60637, USA
- Department of Physics, The University of Chicago, 5740 S Ellis Ave, Chicago, IL 60637, USA
| | - Daphne Preuss
- Department of Molecular Genetics and Cell Biology, CLSC 1106, 920 E 58th St, Chicago, IL 60637, USA
- Current address: Chromatin, Inc, 3440 S Dearborn St, Suite 280, Chicago, IL 60616, USA
- Institute for Biophysical Dynamics, The University of Chicago, 929 E 57th Street, Chicago, IL 60637, USA
| | - Aaron R Dinner
- Department of Chemistry, The University of Chicago, 929 E 57th St, Chicago, IL 60637, USA
- James Franck Institute, The University of Chicago, 929 E 57th St, Chicago, IL 60637, USA
- Institute for Biophysical Dynamics, The University of Chicago, 929 E 57th Street, Chicago, IL 60637, USA
| |
Collapse
|
53
|
Kato N, He H, Steger AP. A systems model of vesicle trafficking in Arabidopsis pollen tubes. PLANT PHYSIOLOGY 2010; 152:590-601. [PMID: 19933386 PMCID: PMC2815877 DOI: 10.1104/pp.109.148700] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/02/2009] [Accepted: 11/16/2009] [Indexed: 05/18/2023]
Abstract
A systems model that describes vesicle trafficking during pollen tube growth in Arabidopsis (Arabidopsis thaliana) was constructed. The model is composed of ordinary differential equations that connect the molecular functions of genes expressed in pollen. The current model requires soluble N-ethylmaleimide-sensitive fusion protein attachment protein receptors (SNAREs) and small GTPases, Arf or Rab, to reasonably predict tube growth as a function of time. Tube growth depends on vesicle trafficking that transports phospholipid and pectin to the tube tip. The vesicle trafficking genes identified by analyzing publicly available transcriptome data comprised 328 genes. Fourteen of them are up-regulated by the gibberellin signaling pathway during pollen development, which includes the SNARE genes SYP124 and SYP125 and the Rab GTPase gene RABA4D. The model results adequately fit the pollen tube growth of both previously reported wild-type and raba4d knockout lines. Furthermore, the difference of pollen tube growth in syp124/syp125 single and double mutations was quantitatively predicted based on the model analysis. In general, a systems model approach to vesicle trafficking arguably demonstrated the importance of the functional connections in pollen tube growth and can help guide future research directions.
Collapse
Affiliation(s)
- Naohiro Kato
- Department of Biological Sciences, Louisiana State University, Baton Rouge, Louisiana 70803, USA.
| | | | | |
Collapse
|
54
|
Chickarmane V, Roeder AH, Tarr PT, Cunha A, Tobin C, Meyerowitz EM. Computational morphodynamics: a modeling framework to understand plant growth. ANNUAL REVIEW OF PLANT BIOLOGY 2010; 61:65-87. [PMID: 20192756 PMCID: PMC4120954 DOI: 10.1146/annurev-arplant-042809-112213] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Computational morphodynamics utilizes computer modeling to understand the development of living organisms over space and time. Results from biological experiments are used to construct accurate and predictive models of growth. These models are then used to make novel predictions that provide further insight into the processes involved, which can be tested experimentally to either confirm or rule out the validity of the computational models. This review highlights two fundamental challenges: (a) to understand the feedback between mechanics of growth and chemical or molecular signaling, and (b) to design models that span and integrate single cell behavior with tissue development. We review different approaches to model plant growth and discuss a variety of model types that can be implemented to demonstrate how the interplay between computational modeling and experimentation can be used to explore the morphodynamics of plant development.
Collapse
Affiliation(s)
- Vijay Chickarmane
- Division of Biology, California Institute Technology, Pasadena, California 91125
| | - Adrienne H.K. Roeder
- Division of Biology, California Institute Technology, Pasadena, California 91125
- Center for Integrative Study of Cell Regulation, California Institute Technology, Pasadena, California 91125
| | - Paul T. Tarr
- Division of Biology, California Institute Technology, Pasadena, California 91125
| | - Alexandre Cunha
- Center for Advanced Computing Research, California Institute Technology, Pasadena, California 91125
- Center for Integrative Study of Cell Regulation, California Institute Technology, Pasadena, California 91125
| | - Cory Tobin
- Division of Biology, California Institute Technology, Pasadena, California 91125
| | - Elliot M. Meyerowitz
- Division of Biology, California Institute Technology, Pasadena, California 91125
| |
Collapse
|
55
|
Krzesłowska M, Lenartowska M, Samardakiewicz S, Bilski H, Woźny A. Lead deposited in the cell wall of Funaria hygrometrica protonemata is not stable--a remobilization can occur. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2010; 158:325-38. [PMID: 19647914 DOI: 10.1016/j.envpol.2009.06.035] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/18/2009] [Revised: 06/19/2009] [Accepted: 06/24/2009] [Indexed: 05/13/2023]
Abstract
The hypothesis that lead (Pb) can be uptake or remobilized from the cell wall (CW) by internalization withlow-esterified pectins (up to 40%--JIM5-P), was studied in tip-growing apical cell of Funaria hygrometrica protonemata. Treatment 4h with 1mM PbCl(2) caused marked vesicular traffic intensification and the common internalization of JIM5-P from the CW. Lead bound to JIM5-P was internalized from the CW, together with this compound and entered the protoplast. It showed that Pb deposited in CW is not as safe for plant cell as previously believed. However, pulse-chase experiments (recovering 4 h and 24 h) indicated that CW and its thickenings can function as the final sequestration compartments. In Pb deposition sites, a callose layer occurred. It was localized from the protoplast site, next to Pb deposits separating sequestrated to CW and its thickenings Pb from plasma membrane almost certainly protecting the plant cell from its returning into the protoplast.
Collapse
Affiliation(s)
- Magdalena Krzesłowska
- Laboratory of General Botany, Faculty of Biology, Adam Mickiewicz University, Umultowska 89, 61-614 Poznań, Poland.
| | | | | | | | | |
Collapse
|
56
|
Kroeger JH, Daher FB, Grant M, Geitmann A. Microfilament orientation constrains vesicle flow and spatial distribution in growing pollen tubes. Biophys J 2009; 97:1822-31. [PMID: 19804712 DOI: 10.1016/j.bpj.2009.07.038] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2009] [Revised: 07/17/2009] [Accepted: 07/21/2009] [Indexed: 12/29/2022] Open
Abstract
The dynamics of cellular organelles reveals important information about their functioning. The spatio-temporal movement patterns of vesicles in growing pollen tubes are controlled by the actin cytoskeleton. Vesicle flow is crucial for morphogenesis in these cells as it ensures targeted delivery of cell wall polysaccharides. Remarkably, the target region does not contain much filamentous actin. We model the vesicular trafficking in this area using as boundary conditions the expanding cell wall and the actin array forming the apical actin fringe. The shape of the fringe was obtained by imposing a steady state and constant polymerization rate of the actin filaments. Letting vesicle flux into and out of the apical region be determined by the orientation of the actin microfilaments and by exocytosis was sufficient to generate a flux that corresponds in magnitude and orientation to that observed experimentally. This model explains how the cytoplasmic streaming pattern in the apical region of the pollen tube can be generated without the presence of actin microfilaments.
Collapse
|
57
|
Lenartowska M, Lenartowski R, Smoliński DJ, Wróbel B, Niedojadło J, Jaworski K, Bednarska E. Calreticulin expression and localization in plant cells during pollen-pistil interactions. PLANTA 2009; 231:67-77. [PMID: 19820965 DOI: 10.1007/s00425-009-1024-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/10/2009] [Accepted: 09/21/2009] [Indexed: 05/24/2023]
Abstract
In this report, the distributions of calreticulin (CRT) and its transcripts in Haemanthus pollen, pollen tubes, and somatic cells of the hollow pistil were studied. Immunoblot analysis of protein extracts from mature anthers, dry and germinated pollen, growing pollen tubes, and unpollinated/pollinated pistils revealed a strong expression of CRT. Both in vitro and in situ studies confirmed the presence of CRT mRNA and protein in pollen/pollen tubes and somatic cells of the pistil transmitting tract. The co-localization of these molecules in ER of these cells suggests that the rough ER is a site of CRT translation. In the pistil, accumulation of the protein in pollen tubes, transmitting tract epidermis (tte), and micropylar cells of the ovule (mc) was correlated with the increased level of exchangeable calcium. Therefore, CRT as a Ca(2+)-binding/buffering protein, may be involved in mechanism of regulation calcium homeostasis in these cells. The functional role of the protein in pollen-pistil interactions, apart from its postulated function in cellular Ca(2+) homeostasis, is discussed.
Collapse
Affiliation(s)
- Marta Lenartowska
- Laboratory of Developmental Biology, Nicolaus Copernicus University, Gagarina 9, 87-100, Toruń, Poland.
| | | | | | | | | | | | | |
Collapse
|
58
|
Zerzour R, Kroeger J, Geitmann A. Polar growth in pollen tubes is associated with spatially confined dynamic changes in cell mechanical properties. Dev Biol 2009; 334:437-46. [PMID: 19666018 DOI: 10.1016/j.ydbio.2009.07.044] [Citation(s) in RCA: 107] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2009] [Revised: 07/31/2009] [Accepted: 07/31/2009] [Indexed: 12/16/2022]
Abstract
Cellular morphogenesis involves changes to cellular size and shape which in the case of walled cells implies the mechanical deformation of the extracellular matrix. So far, technical challenges have made quantitative mechanical measurements of this process at subcellular scale impossible. We used micro-indentation to investigate the dynamic changes in the cellular mechanical properties during the onset of spatially confined growth activities in plant cells. Pollen tubes are cellular protuberances that have a strictly unidirectional growth pattern. Micro-indentation of these cells revealed that the initial formation of a cylindrical protuberance is preceded by a local reduction in cellular stiffness. Similar cellular softening was observed before the onset of a rapid growth phase in cells with oscillating growth pattern. These findings provide the first quantitative cytomechanical data that confirm the important role of the mechanical properties of the cell wall for local cellular growth processes. They are consistent with a conceptual model that explains pollen tube oscillatory growth based on the relationship between turgor pressure and tensile resistance in the apical cell wall. To further confirm the significance of cell mechanics, we artificially manipulated the mechanical cell wall properties as well as the turgor pressure. We observed that these changes affected the oscillation profile and were able to induce oscillatory behavior in steadily growing tubes.
Collapse
Affiliation(s)
- Rabah Zerzour
- Institut de recherche en biologie végétale, Département de sciences biologiques, Université de Montréal, 4101 rue Sherbrooke est, Montréal Québec, Canada H1X 2B2
| | | | | |
Collapse
|
59
|
Moscatelli A, Idilli AI. Pollen tube growth: a delicate equilibrium between secretory and endocytic pathways. JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2009; 51:727-39. [PMID: 19686370 DOI: 10.1111/j.1744-7909.2009.00842.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Although pollen tube growth is a prerequisite for higher plant fertilization and seed production, the processes leading to pollen tube emission and elongation are crucial for understanding the basic mechanisms of tip growth. It was generally accepted that pollen tube elongation occurs by accumulation and fusion of Golgi-derived secretory vesicles (SVs) in the apical region, or clear zone, where they were thought to fuse with a restricted area of the apical plasma membrane (PM), defining the apical growth domain. Fusion of SVs at the tip reverses outside cell wall material and provides new segments of PM. However, electron microscopy studies have clearly shown that the PM incorporated at the tip greatly exceeds elongation and a mechanism of PM retrieval was already postulated in the mid-nineteenth century. Recent studies on endocytosis during pollen tube growth showed that different endocytic pathways occurred in distinct zones of the tube, including the apex, and led to a new hypothesis to explain vesicle accumulation at the tip; namely, that endocytic vesicles contribute substantially to V-shaped vesicle accumulation in addition to SVs and that exocytosis does not involve the entire apical domain. New insights suggested the intriguing hypothesis that modulation between exo- and endocytosis in the apex contributes to maintain PM polarity in terms of lipid/protein composition and showed distinct degradation pathways that could have different functions in the physiology of the cell. Pollen tube growth in vivo is closely regulated by interaction with style molecules. The study of endocytosis and membrane recycling in pollen tubes opens new perspectives to studying pollen tube-style interactions in vivo.
Collapse
Affiliation(s)
- Alessandra Moscatelli
- Dipartimento di Biologia L. Gorini, Università degli Studi di Milano, Milano, Italy.
| | | |
Collapse
|
60
|
Zonia L, Munnik T. Uncovering hidden treasures in pollen tube growth mechanics. TRENDS IN PLANT SCIENCE 2009; 14:318-27. [PMID: 19446491 DOI: 10.1016/j.tplants.2009.03.008] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/03/2008] [Revised: 02/22/2009] [Accepted: 03/03/2009] [Indexed: 05/08/2023]
Abstract
The long-standing model of tip growth in pollen tubes considers that exocytosis and growth occur at the apex and that the pool of very small vesicles in the apical dome contains secretory (exocytic) vesicles. However, recent work on vesicle trafficking dynamics in tobacco pollen tubes shows that exocytosis occurs in the subapical region. Taking these and other new results into account, we set out to resolve specific problems that are endemic in current models and present a two-part ACE (apical cap extension)-H (hydrodynamics) growth model. The ACE model involves delivery and recycling of materials required for new cell synthesis and the H model involves mechanisms that integrate and regulate key cellular pathways and drive cell elongation during growth.
Collapse
Affiliation(s)
- Laura Zonia
- Swammerdam Institute for Life Sciences, Plant Physiology Section, University of Amsterdam, Kruislaan 904, 1098 XH Amsterdam, The Netherlands.
| | | |
Collapse
|
61
|
Sinclair A, Schenkel M, Mathur J. Signaling to the Actin Cytoskeleton During Cell Morphogenesis and Patterning. SIGNALING IN PLANTS 2009. [DOI: 10.1007/978-3-540-89228-1_7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
|