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Del Casino C, Conti V, Licata S, Cai G, Cantore A, Ricci C, Cantara S. Mitigation of UV-B Radiation Stress in Tobacco Pollen by Expression of the Tardigrade Damage Suppressor Protein (Dsup). Cells 2024; 13:840. [PMID: 38786062 PMCID: PMC11119994 DOI: 10.3390/cells13100840] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2024] [Revised: 04/19/2024] [Accepted: 04/23/2024] [Indexed: 05/25/2024] Open
Abstract
Pollen, the male gametophyte of seed plants, is extremely sensitive to UV light, which may prevent fertilization. As a result, strategies to improve plant resistance to solar ultraviolet (UV) radiation are required. The tardigrade damage suppressor protein (Dsup) is a putative DNA-binding protein that enables tardigrades to tolerate harsh environmental conditions, including UV radiation, and was therefore considered as a candidate for reducing the effects of UV exposure on pollen. Tobacco pollen was genetically engineered to express Dsup and then exposed to UV-B radiation to determine the effectiveness of the protein in increasing pollen resistance. To establish the preventive role of Dsup against UV-B stress, we carried out extensive investigations into pollen viability, germination rate, pollen tube length, male germ unit position, callose plug development, marker protein content, and antioxidant capacity. The results indicated that UV-B stress has a significant negative impact on both pollen grain and pollen tube growth. However, Dsup expression increased the antioxidant levels and reversed some of the UV-B-induced changes to pollen, restoring the proper distance between the tip and the last callose plug formed, as well as pollen tube length, tubulin, and HSP70 levels. Therefore, the expression of heterologous Dsup in pollen may provide the plant male gametophyte with enhanced responses to UV-B stress and protection against harmful environmental radiation.
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Affiliation(s)
- Cecilia Del Casino
- Dipartimento di Scienze della Vita, University of Siena, via Mattioli 4, 53100 Siena, Italy; (C.D.C.); (S.L.)
| | - Veronica Conti
- Dipartimento di Scienze Biologiche, Geologiche e Ambientali, Università di Bologna, via Irnerio 42, 40126 Bologna, Italy;
| | - Silvia Licata
- Dipartimento di Scienze della Vita, University of Siena, via Mattioli 4, 53100 Siena, Italy; (C.D.C.); (S.L.)
| | - Giampiero Cai
- Dipartimento di Scienze della Vita, University of Siena, via Mattioli 4, 53100 Siena, Italy; (C.D.C.); (S.L.)
| | - Anna Cantore
- Department of Medical, Surgical and Neurological Sciences, University of Siena, Viale Bracci, 53100 Siena, Italy; (A.C.); (C.R.); (S.C.)
| | - Claudia Ricci
- Department of Medical, Surgical and Neurological Sciences, University of Siena, Viale Bracci, 53100 Siena, Italy; (A.C.); (C.R.); (S.C.)
| | - Silvia Cantara
- Department of Medical, Surgical and Neurological Sciences, University of Siena, Viale Bracci, 53100 Siena, Italy; (A.C.); (C.R.); (S.C.)
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2
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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 PMCID: PMC9926264 DOI: 10.1073/pnas.2211416120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [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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3
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Stroppa N, Onelli E, Moreau P, Maneta-Peyret L, Berno V, Cammarota E, Ambrosini R, Caccianiga M, Scali M, Moscatelli A. Sterols and Sphingolipids as New Players in Cell Wall Building and Apical Growth of Nicotiana tabacum L. Pollen Tubes. PLANTS (BASEL, SWITZERLAND) 2022; 12:8. [PMID: 36616135 PMCID: PMC9824051 DOI: 10.3390/plants12010008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/19/2022] [Revised: 12/05/2022] [Accepted: 12/12/2022] [Indexed: 06/17/2023]
Abstract
Pollen tubes are tip-growing cells that create safe routes to convey sperm cells to the embryo sac for double fertilization. Recent studies have purified and biochemically characterized detergent-insoluble membranes from tobacco pollen tubes. These microdomains, called lipid rafts, are rich in sterols and sphingolipids and are involved in cell polarization in organisms evolutionarily distant, such as fungi and mammals. The presence of actin in tobacco pollen tube detergent-insoluble membranes and the preferential distribution of these domains on the apical plasma membrane encouraged us to formulate the intriguing hypothesis that sterols and sphingolipids could be a "trait d'union" between actin dynamics and polarized secretion at the tip. To unravel the role of sterols and sphingolipids in tobacco pollen tube growth, we used squalestatin and myriocin, inhibitors of sterol and sphingolipid biosynthesis, respectively, to determine whether lipid modifications affect actin fringe morphology and dynamics, leading to changes in clear zone organization and cell wall deposition, thus suggesting a role played by these lipids in successful fertilization.
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Affiliation(s)
- Nadia Stroppa
- Dipartimento di Bioscienze, Università degli Studi di Milano, Via Celoria 26, 20133 Milan, Italy
| | - Elisabetta Onelli
- Dipartimento di Bioscienze, Università degli Studi di Milano, Via Celoria 26, 20133 Milan, Italy
| | - Patrick Moreau
- CNRS, Laboratoire de Biogenèse Membranaire, University of Bordeaux, UMR 5200, 71 Avenue Edouard Bourlaux, 33140 Villenave d’Ornon, France
| | - Lilly Maneta-Peyret
- CNRS, Laboratoire de Biogenèse Membranaire, University of Bordeaux, UMR 5200, 71 Avenue Edouard Bourlaux, 33140 Villenave d’Ornon, France
| | - Valeria Berno
- ALEMBIC Advanced Light and Electron Microscopy BioImaging Center, San Raffaele Scientific Institute, DIBIT 1, Via Olgettina 58, 20132 Milan, Italy
| | - Eugenia Cammarota
- ALEMBIC Advanced Light and Electron Microscopy BioImaging Center, San Raffaele Scientific Institute, DIBIT 1, Via Olgettina 58, 20132 Milan, Italy
| | - Roberto Ambrosini
- Dipartimento di Scienze e Politiche Ambientali, Università degli Studi di Milano, Via Celoria 26, 20133 Milan, Italy
| | - Marco Caccianiga
- Dipartimento di Bioscienze, Università degli Studi di Milano, Via Celoria 26, 20133 Milan, Italy
| | - Monica Scali
- Dipartimento di Scienze della Vita, Università degli Studi di Siena, Via Aldo Moro 2, 53100 Siena, Italy
| | - Alessandra Moscatelli
- Dipartimento di Bioscienze, Università degli Studi di Milano, Via Celoria 26, 20133 Milan, Italy
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4
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Çetinbaş-Genç A, Conti V, Cai G. Let's shape again: the concerted molecular action that builds the pollen tube. PLANT REPRODUCTION 2022; 35:77-103. [PMID: 35041045 DOI: 10.1007/s00497-022-00437-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Accepted: 01/06/2022] [Indexed: 06/14/2023]
Abstract
The pollen tube is being subjected to control by a complex network of communication that regulates its shape and the misfunction of a single component causes specific deformations. In flowering plants, the pollen tube is a tubular extension of the pollen grain required for successful sexual reproduction. Indeed, maintaining the unique shape of the pollen tube is essential for the pollen tube to approach the embryo sac. Many processes and molecules (such as GTPase activity, phosphoinositides, Ca2+ gradient, distribution of reactive oxygen species and nitric oxide, nonuniform pH values, organization of the cytoskeleton, balance between exocytosis and endocytosis, and cell wall structure) play key and coordinated roles in maintaining the cylindrical shape of pollen tubes. In addition, the above factors must also interact with each other so that the cell shape is maintained while the pollen tube follows chemical signals in the pistil that guide it to the embryo sac. Any intrinsic changes (such as erroneous signals) or extrinsic changes (such as environmental stresses) can affect the above factors and thus fertilization by altering the tube morphology. In this review, the processes and molecules that enable the development and maintenance of the unique shape of pollen tubes in angiosperms are presented emphasizing their interaction with specific tube shape. Thus, the purpose of the review is to investigate whether specific deformations in pollen tubes can help us to better understand the mechanism underlying pollen tube shape.
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Affiliation(s)
- Aslıhan Çetinbaş-Genç
- Department of Biology, Marmara University, Göztepe Campus, 34722, Kadıköy, Istanbul, Turkey.
| | - Veronica Conti
- Department of Life Sciences, University of Siena, via Mattioli 4, 53100, Siena, Italy
| | - Giampiero Cai
- Department of Life Sciences, University of Siena, via Mattioli 4, 53100, Siena, Italy
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5
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Hendriks PW, Ryan PR, Hands P, Rolland V, Gurusinghe S, Weston LA, Rebetzke GJ, Delhaize E. Selection for early shoot vigour in wheat increases root hair length but reduces epidermal cell size of roots and leaves. JOURNAL OF EXPERIMENTAL BOTANY 2022; 73:2499-2510. [PMID: 35195714 PMCID: PMC9015806 DOI: 10.1093/jxb/erac048] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2021] [Accepted: 02/11/2022] [Indexed: 05/22/2023]
Abstract
Six cycles of recurrent selection for early shoot vigour in wheat resulted in significant increases in leaf width and shoot biomass. Here, in replicated controlled-environment studies, the effect of early shoot vigour on root biomass, rhizosheath size, root hair length, and cell size in the roots and leaves was examined across different cycles of selection. Increased shoot vigour was associated with greater root biomass, larger rhizosheath size, and longer root hairs. Our findings demonstrate that rhizosheath size was a reliable surrogate for root hair length in this germplasm. Examination of the root epidermis revealed that the 'cell body' of the trichoblasts (hair-forming cells) and the atrichoblasts (non-hair-forming cells) decreased in size as shoot vigour increased. Therefore, in higher vigour germplasm, longer root hairs emerged from smaller trichoblasts so that total trichoblast volume (root hair plus cell body) was generally similar regardless of shoot vigour. Similarly, the sizes of the four main cell types on the leaf epidermis became progressively smaller as shoot vigour increased, which also increased stomatal density. The relationship between shoot vigour and root traits is considered, and the potential contribution of below-ground root traits to performance and competitiveness of high vigour germplasm is discussed.
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Affiliation(s)
- Pieter-Willem Hendriks
- CSIRO, Agriculture and Food, Canberra, ACT, 2601, Australia
- Charles Sturt University, School of Agriculture, Environment and Veterinary Sciences, Wagga-Wagga, 14 NSW, 2650, Australia
- Graham Centre for Agricultural Innovation, Wagga Wagga, NSW, 2678, Australia
- Correspondence:
| | - Peter R Ryan
- CSIRO, Agriculture and Food, Canberra, ACT, 2601, Australia
| | - Philip Hands
- CSIRO, Agriculture and Food, Canberra, ACT, 2601, Australia
| | - Vivien Rolland
- CSIRO, Agriculture and Food, Canberra, ACT, 2601, Australia
| | - Saliya Gurusinghe
- Graham Centre for Agricultural Innovation, Wagga Wagga, NSW, 2678, Australia
| | - Leslie A Weston
- Graham Centre for Agricultural Innovation, Wagga Wagga, NSW, 2678, Australia
| | | | - Emmanuel Delhaize
- Australian Plant Phenomics Facility, Australian National University Node, 134 Linnaeus Way, Acton ACT 2601, Australia
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6
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Male Fertility under Environmental Stress: Do Polyamines Act as Pollen Tube Growth Protectants? Int J Mol Sci 2022; 23:ijms23031874. [PMID: 35163795 PMCID: PMC8836739 DOI: 10.3390/ijms23031874] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2022] [Revised: 02/02/2022] [Accepted: 02/04/2022] [Indexed: 02/06/2023] Open
Abstract
Although pollen structure and morphology evolved toward the optimization of stability and fertilization efficiency, its performance is affected by harsh environmental conditions, e.g., heat, cold, drought, pollutants, and other stressors. These phenomena are expected to increase in the coming years in relation to predicted environmental scenarios, contributing to a rapid increase in the interest of the scientific community in understanding the molecular and physiological responses implemented by male gametophyte to accomplish reproduction. Here, after a brief introduction summarizing the main events underlying pollen physiology with a focus on polyamine involvement in its development and germination, we review the main effects that environmental stresses can cause on pollen. We report the most relevant evidence in the literature underlying morphological, cytoskeletal, metabolic and signaling alterations involved in stress perception and response, focusing on the final stage of pollen life, i.e., from when it hydrates, to pollen tube growth and sperm cell transport, with these being the most sensitive to environmental changes. Finally, we hypothesize the molecular mechanisms through which polyamines, well-known molecules involved in plant development, stress response and adaptation, can exert a protective action against environmental stresses in pollen by decoding the essential steps and the intersection between polyamines and pollen tube growth mechanisms.
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7
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Dumais J. Mechanics and hydraulics of pollen tube growth. THE NEW PHYTOLOGIST 2021; 232:1549-1565. [PMID: 34492127 DOI: 10.1111/nph.17722] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2021] [Accepted: 08/21/2021] [Indexed: 06/13/2023]
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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8
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Winship LJ, Rosen GA, Hepler PK. Apical pollen tube wall curvature correlates with growth and indicates localized changes in the yielding of the cell wall. PROTOPLASMA 2021; 258:1347-1358. [PMID: 34414478 DOI: 10.1007/s00709-021-01694-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Accepted: 07/26/2021] [Indexed: 05/16/2023]
Abstract
The shape of the apical region of lily pollen tube changes rhythmically as the growth rate of the tube oscillates becoming alternately more prolate then back to oblate. We quantified shape change by calculating the curvature of the cross-sectional edge of the pollen tube tip and cross-correlating curvature changes with growth rate. The apical region takes the form of a partial elliptical spheroid, with variation in the length and location of the minor axis. During oscillation curvature profiles show a sharp increase in curvature at the "shoulders" of the apex when oblate, 4-7 μm from the flatter central zone. As the tip becomes more prolate, the "shoulders" decrease rapidly in curvature and move towards the growth axis as curvature at the tip increases. We understand curvature changes to represent differential changes in local wall expansion rates, driven by uniform turgor pressure and mediated by changes in wall polysaccharides. To become more oblate, the tip region must become less extensible than the "shoulder" region. And, as the tip becomes more prolate, the increased curvature must be due to increased local expansion. We found that changes in the growth velocity of the "shoulders" of the cell measured as the progress of the cell edge along the growth axis are cyclically out of phase with growth velocity at the tip such that the shoulder regions lag for part of the oscillation cycle, then "catch up" as the growth rate at the tip reaches a maximum and begins to decline. In this way the cell becomes oblate. Cell shape and growth rate oscillate in concert and are functionally related. Spatial change in edge growth rate points to important cellular locations for further investigation of vesicle movement and exocytosis, calcium gradients, and actin dynamics in lily pollen tubes.
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Affiliation(s)
| | - Grace A Rosen
- Hampshire College, Amherst, MA, 01002, USA
- VA Boston Healthcare System, 150 South Huntington Avenue, Boston, MA, 02130, USA
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9
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Ke CJ, Lin XJ, Zhang BY, Chen LY. Turgor regulation defect 1 proteins play a conserved role in pollen tube reproductive innovation of the angiosperms. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2021; 106:1356-1365. [PMID: 33735469 DOI: 10.1111/tpj.15241] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Revised: 03/11/2021] [Accepted: 03/16/2021] [Indexed: 06/12/2023]
Abstract
Sexual reproduction in angiosperms is siphonogamous, and the interaction between pollen tube and pistil is critical for successful fertilization. Our previous study demonstrated that mutation of the Arabidopsis turgor regulation defect 1 (TOD1) gene leads to reduced male fertility, a result of retarded pollen tube growth in the pistil. TOD1 encodes a Golgi-localized alkaline ceramidase, a key enzyme for the production of sphingosine-1-phosphate (S1P), which is involved in the regulation of turgor pressure in plant cells. However, whether TOD1s play a conserved role in the innovation of siphonogamy is largely unknown. In this study, we provide evidence that OsTOD1, which is similar to AtTOD1, is also preferentially expressed in rice pollen grains and pollen tubes. OsTOD1 knockout results in reduced pollen tube growth potential in rice pistil. Both the OsTOD1 genomic sequence with its own promoter and the coding sequence under the AtTOD1 promoter can partially rescue the attod1 mutant phenotype. Furthermore, TOD1s from other angiosperm species can partially rescue the attod1 mutant phenotype, while TOD1s from gymnosperm species are not able to complement the attod1 mutant phenotype. Our data suggest that TOD1 acts conservatively in angiosperms, and this opens up an opportunity to dissect the role of sphingolipids in pollen tube growth in angiosperms.
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Affiliation(s)
- Chang-Jiao Ke
- Fujian Provincial Key Laboratory of Haixia Applied Plant Systems Biology, Key Laboratory of Ministry of Education for Genetics, Breeding and Multiple Utilization of Crops, Center for Genomics and Biotechnology, College of Agriculture, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Xian-Ju Lin
- Fujian Provincial Key Laboratory of Haixia Applied Plant Systems Biology, Key Laboratory of Ministry of Education for Genetics, Breeding and Multiple Utilization of Crops, Center for Genomics and Biotechnology, College of Agriculture, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Bao-Yu Zhang
- Fujian Provincial Key Laboratory of Haixia Applied Plant Systems Biology, Key Laboratory of Ministry of Education for Genetics, Breeding and Multiple Utilization of Crops, Center for Genomics and Biotechnology, College of Agriculture, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
- College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Li-Yu Chen
- Fujian Provincial Key Laboratory of Haixia Applied Plant Systems Biology, Key Laboratory of Ministry of Education for Genetics, Breeding and Multiple Utilization of Crops, Center for Genomics and Biotechnology, College of Agriculture, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
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10
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Wollenweber TE, van Deenen N, Roelfs KU, Prüfer D, Gronover CS. Microscopic and Transcriptomic Analysis of Pollination Processes in Self-Incompatible Taraxacum koksaghyz. PLANTS 2021; 10:plants10030555. [PMID: 33809548 PMCID: PMC7998978 DOI: 10.3390/plants10030555] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Revised: 03/12/2021] [Accepted: 03/13/2021] [Indexed: 11/23/2022]
Abstract
The transition of the Russian dandelion Taraxacum koksaghyz (Asteraceae) to a profitable, alternative crop producing natural rubber and inulin requires the optimization of several agronomic traits, cultivation conditions and harvesting procedures to improve the yield. However, efficient breeding is hindered by the obligatory sexual outcrossing of this species. Several other asters have been investigated to determine the mechanism of self-incompatibility, but the underlying molecular basis remains unclear. We therefore investigated the self-pollination and cross-pollination of two compatible T. koksaghyz varieties (TkMS2 and TkMS3) by microscopy and transcriptomic analysis to shed light on the pollination process. Self-pollination showed typical sporophytic self-incompatibility characteristics, with the rare pollen swelling at the pollen tube apex. In contrast, cross-pollination was characterized by pollen germination and penetration of the stigma by the growing pollen tubes. RNA-Seq was used to profile gene expression in the floret tissue during self-pollination and cross-pollination, and the differentially expressed genes were identified. This revealed three candidates for the early regulation of pollination in T. koksaghyz, which can be used to examine self-incompatibility mechanisms in more detail and to facilitate breeding programs.
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Affiliation(s)
- Tassilo Erik Wollenweber
- Institute of Plant Biology and Biotechnology, University of Muenster, Schlossplatz 8, 48143 Muenster, Germany; (T.E.W.); (N.v.D.); (D.P.)
| | - Nicole van Deenen
- Institute of Plant Biology and Biotechnology, University of Muenster, Schlossplatz 8, 48143 Muenster, Germany; (T.E.W.); (N.v.D.); (D.P.)
| | - Kai-Uwe Roelfs
- Fraunhofer Institute for Molecular Biology and Applied Ecology IME, Schlossplatz 8, 48143 Muenster, Germany;
| | - Dirk Prüfer
- Institute of Plant Biology and Biotechnology, University of Muenster, Schlossplatz 8, 48143 Muenster, Germany; (T.E.W.); (N.v.D.); (D.P.)
- Fraunhofer Institute for Molecular Biology and Applied Ecology IME, Schlossplatz 8, 48143 Muenster, Germany;
| | - Christian Schulze Gronover
- Fraunhofer Institute for Molecular Biology and Applied Ecology IME, Schlossplatz 8, 48143 Muenster, Germany;
- Correspondence: ; Tel.: +49(0)251-83-24998
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11
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Cascallares M, Setzes N, Marchetti F, López GA, Distéfano AM, Cainzos M, Zabaleta E, Pagnussat GC. A Complex Journey: Cell Wall Remodeling, Interactions, and Integrity During Pollen Tube Growth. FRONTIERS IN PLANT SCIENCE 2020; 11:599247. [PMID: 33329663 PMCID: PMC7733995 DOI: 10.3389/fpls.2020.599247] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Accepted: 11/02/2020] [Indexed: 05/05/2023]
Abstract
In flowering plants, pollen tubes undergo a journey that starts in the stigma and ends in the ovule with the delivery of the sperm cells to achieve double fertilization. The pollen cell wall plays an essential role to accomplish all the steps required for the successful delivery of the male gametes. This extended path involves female tissue recognition, rapid hydration and germination, polar growth, and a tight regulation of cell wall synthesis and modification, as its properties change not only along the pollen tube but also in response to guidance cues inside the pistil. In this review, we focus on the most recent advances in elucidating the molecular mechanisms involved in the regulation of cell wall synthesis and modification during pollen germination, pollen tube growth, and rupture.
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Affiliation(s)
| | | | | | | | | | | | | | - Gabriela Carolina Pagnussat
- Instituto de Investigaciones Biológicas, Universidad Nacional de Mar del Plata, CONICET, Mar del Plata, Argentina
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12
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Williams JH, Oliveira PE. For things to stay the same, things must change: polyploidy and pollen tube growth rates. ANNALS OF BOTANY 2020; 125:925-935. [PMID: 31957784 PMCID: PMC7218811 DOI: 10.1093/aob/mcaa007] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2019] [Accepted: 01/17/2020] [Indexed: 05/13/2023]
Abstract
BACKGROUND AND AIMS Pollen tube growth rate (PTGR) is an important single-cell performance trait that may evolve rapidly under haploid selection. Angiosperms have experienced repeated cycles of polyploidy (whole genome duplication), and polyploidy has cell-level phenotypic consequences arising from increased bulk DNA amount and numbers of genes and their interactions. We sought to understand potential effects of polyploidy on several underlying determinants of PTGR - pollen tube dimensions and construction rates - by comparing diploid-polyploid near-relatives in Betula (Betulaceae) and Handroanthus (Bignoniaceae). METHODS We performed intraspecific, outcrossed hand-pollinations on pairs of flowers. In one flower, PTGR was calculated from the longest pollen tube per time of tube elongation. In the other, styles were embedded in glycol methacrylate, serial-sectioned in transverse orientation, stained and viewed at 1000× to measure tube wall thicknesses (W) and circumferences (C). Volumetric growth rate (VGR) and wall production rate (WPR) were then calculated for each tube by multiplying cross-sectional tube area (πr2) or wall area (W × C), by the mean PTGR of each maternal replicate respectively. KEY RESULTS In Betula and Handroanthus, the hexaploid species had significantly wider pollen tubes (13 and 25 %, respectively) and significantly higher WPRs (22 and 18 %, respectively) than their diploid congeners. PTGRs were not significantly different in both pairs, even though wider polyploid tubes were predicted to decrease PTGRs by 16 and 20 %, respectively. CONCLUSIONS The larger tube sizes of polyploids imposed a substantial materials cost on PTGR, but polyploids also exhibited higher VGRs and WPRs, probably reflecting the evolution of increased metabolic activity. Recurrent cycles of polyploidy followed by genome reorganization may have been important for the evolution of fast PTGRs in angiosperms, involving a complex interplay between correlated changes in ploidy level, genome size, cell size and pollen tube energetics.
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Affiliation(s)
- Joseph H Williams
- Department of Ecology and Evolutionary Biology, University of Tennessee, Knoxville, TN, USA
| | - Paulo E Oliveira
- Instituto de Biologia, Universidade Federal de Uberlândia, Campus Umuarama, Uberlândia, Minas Gerais 38405-320 Brazil
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13
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Parrotta L, Faleri C, Guerriero G, Cai G. Cold stress affects cell wall deposition and growth pattern in tobacco pollen tubes. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2019; 283:329-342. [PMID: 31128704 DOI: 10.1016/j.plantsci.2019.03.010] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2018] [Revised: 01/29/2019] [Accepted: 03/15/2019] [Indexed: 05/08/2023]
Abstract
Cold is an abiotic stress seriously threatening crop productivity by decreasing biomass production. The pollen tube is a target of cold stress, but also a useful model to address questions on cell wall biosynthesis. We here provide (immuno)cytological data relative to the impact of cold on the pollen tube cell wall. We clearly show that the growth pattern is severely affected by the stress, since the typical pulsed-growth mechanism accompanied by the periodic deposition of pectin rings is absent/severely reduced. Additionally, pectins and cellulose accumulate in bulges provoked by the stress, while callose, which colocalizes with pectins in the periodic rings formed during pulsed growth, accumulates randomly in the stressed samples. The altered distribution of the cell wall components is accompanied by differences in the localization of glucan synthases: cellulose synthase shows a more diffuse localization, while callose synthase shows a more frequent cytoplasmic accumulation, thereby denoting a failure in plasma membrane insertion. The cell wall observations are complemented by the analysis of intracellular Ca2+, pH and reactive oxygen species (ROS): while in the case of pH no major differences are observed, a less focused Ca2+ and ROS gradients are present in the stressed samples. The standard oscillatory growth of pollen tubes is recovered by transient changes of turgor pressure induced by hypoosmotic media. Overall our data contribute to the understanding of the impact that cold stress has on the normal development of the pollen tube and unveil the cell wall-related aberrant features accompanying the observed alterations.
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Affiliation(s)
- Luigi Parrotta
- Università di Bologna, Dipartimento di Scienze Biologiche, Geologiche e Ambientali, Via Irnerio 42, Bologna, Italy
| | - Claudia Faleri
- Università di Siena, Dipartimento di Scienze della Vita, via P.A. Mattioli 4, Siena, Italy
| | - Gea Guerriero
- Research and Innovation Department, Luxembourg Institute of Science and Technology, 5 avenue des Hauts-Fourneaux, L-4362, Esch/Alzette, Luxembourg
| | - Giampiero Cai
- Università di Siena, Dipartimento di Scienze della Vita, via P.A. Mattioli 4, Siena, Italy.
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Dehors J, Mareck A, Kiefer-Meyer MC, Menu-Bouaouiche L, Lehner A, Mollet JC. Evolution of Cell Wall Polymers in Tip-Growing Land Plant Gametophytes: Composition, Distribution, Functional Aspects and Their Remodeling. FRONTIERS IN PLANT SCIENCE 2019; 10:441. [PMID: 31057570 PMCID: PMC6482432 DOI: 10.3389/fpls.2019.00441] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2019] [Accepted: 03/22/2019] [Indexed: 05/22/2023]
Abstract
During evolution of land plants, the first colonizing species presented leafy-dominant gametophytes, found in non-vascular plants (bryophytes). Today, bryophytes include liverworts, mosses, and hornworts. In the first seedless vascular plants (lycophytes), the sporophytic stage of life started to be predominant. In the seed producing plants, gymnosperms and angiosperms , the gametophytic stage is restricted to reproduction. In mosses and ferns, the haploid spores germinate and form a protonema, which develops into a leafy gametophyte producing rhizoids for anchorage, water and nutrient uptakes. The basal gymnosperms (cycads and Ginkgo) reproduce by zooidogamy. Their pollen grains develop a multi-branched pollen tube that penetrates the nucellus and releases flagellated sperm cells that swim to the egg cell. The pollen grain of other gymnosperms (conifers and gnetophytes) as well as angiosperms germinates and produces a pollen tube that directly delivers the sperm cells to the ovule (siphonogamy). These different gametophytes, which are short or long-lived structures, share a common tip-growing mode of cell expansion. Tip-growth requires a massive cell wall deposition to promote cell elongation, but also a tight spatial and temporal control of the cell wall remodeling in order to modulate the mechanical properties of the cell wall. The growth rate of these cells is very variable depending on the structure and the species, ranging from very slow (protonemata, rhizoids, and some gymnosperm pollen tubes), to a slow to fast-growth in other gymnosperms and angiosperms. In addition, the structural diversity of the female counterparts in angiosperms (dry, semi-dry vs wet stigmas, short vs long, solid vs hollow styles) will impact the speed and efficiency of sperm delivery. As the evolution and diversity of the cell wall polysaccharides accompanied the diversification of cell wall structural proteins and remodeling enzymes, this review focuses on our current knowledge on the biochemistry, the distribution and remodeling of the main cell wall polymers (including cellulose, hemicelluloses, pectins, callose, arabinogalactan-proteins and extensins), during the tip-expansion of gametophytes from bryophytes, pteridophytes (lycophytes and monilophytes), gymnosperms and the monocot and eudicot angiosperms.
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15
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Abstract
With the origin of pollination in ancient seed plants, the male gametophyte ("pollen") began to evolve a new and unique life history stage, the progamic phase, a post-pollination period in which pollen sexual maturation occurs in interaction with sporophyte-derived tissues. Pollen performance traits mediate the timing of the fertilization process, often in competition with other pollen, via the speed of pollen germination, sperm development, and pollen tube growth. Studies of pollen development rarely address the issue of performance or its evolution, which involves linking variation in developmental rates to relative fitness within populations or to adaptations on a macroevolutionary scale. Modifications to the pollen tube pathway and changes in the intensity of pollen competition affect the direction and strength of selection on pollen performance. Hence, pollen developmental evolution is always contextual-it involves both the population biology of pollen reaching stigmas and the co-evolution of sporophytic traits, such as the pollen tube pathway and mating system. For most species, performance evolution generally reflects a wandering history of periods of directional selection and relaxed selection, channeled by developmental limitations, a pattern that favors the accumulation of diversity and redundancy in developmental mechanisms and the genetic machinery. Developmental biologists are focused on finding universal mechanisms that underlie pollen function, and these are largely mechanisms that have evolved through their effects on performance. Here, we suggest ways in which studies of pollen performance or function could progress by cross-fertilization between the "evo" and "devo" fields.
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Affiliation(s)
- Joseph H Williams
- Department of Ecology and Evolutionary Biology, University of Tennessee, Knoxville, TN, United States.
| | - John B Reese
- Department of Ecology and Evolutionary Biology, University of Tennessee, Knoxville, TN, United States
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16
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Li G, Yang X, Zhang X, Song Y, Liang W, Zhang D. Rice Morphology Determinant-Mediated Actin Filament Organization Contributes to Pollen Tube Growth. PLANT PHYSIOLOGY 2018; 177:255-270. [PMID: 29581178 PMCID: PMC5933118 DOI: 10.1104/pp.17.01759] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/09/2018] [Accepted: 03/19/2018] [Indexed: 05/25/2023]
Abstract
For successful fertilization in angiosperms, rapid tip growth in pollen tubes delivers the male gamete into the ovules. The actin-binding protein-mediated organization of the actin cytoskeleton within the pollen tube plays a crucial role in this polarized process. However, the mechanism underlying the polarity of the actin filament (F-actin) array and behaviors in pollen tube growth remain largely unknown. Here, we demonstrate that an actin-organizing protein, Rice Morphology Determinant (RMD), a type II formin from rice (Oryza sativa), controls pollen tube growth by modulating the polarity and distribution of the F-actin array. The rice rmd mutant exhibits abnormal pollen tube growth and a decreased germination rate of the pollen grain in vitro and in vivo. The rmd pollen tubes display a disorganized F-actin pattern with disrupted apical actin density and shank longitudinal cable direction/arrangement, indicating the novel role of RMD in F-actin polarity during tip growth. Consistent with this role, RMD localizes at the tip of the rice pollen tube, which is essential for pollen tube growth and polarity as well as F-actin organization. Furthermore, the direction and characteristics of the RMD-guided F-actin array positively regulate the deposition of cell wall components and the pattern and velocity of cytoplasmic streaming during rice pollen tube growth. Collectively, our results suggest that RMD is essential for the spatial regulation of pollen tube growth via modulating F-actin organization and array orientation in rice. This work provides insights into tip-focused cell growth and polarity.
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Affiliation(s)
- Gang Li
- University of Adelaide-Shanghai Jiao Tong University Joint Laboratory for Plant Science and Breeding, School of Agriculture, Food, and Wine, University of Adelaide, Waite Campus, Urrbrae, South Australia 5064, Australia
| | - Xiujuan Yang
- University of Adelaide-Shanghai Jiao Tong University Joint Laboratory for Plant Science and Breeding, School of Agriculture, Food, and Wine, University of Adelaide, Waite Campus, Urrbrae, South Australia 5064, Australia
| | - Xiaoqing Zhang
- Joint International Research Laboratory of Metabolic and Developmental Sciences, Shanghai Jiao Tong University-University of Adelaide Joint Centre for Agriculture and Health, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Yu Song
- Joint International Research Laboratory of Metabolic and Developmental Sciences, Shanghai Jiao Tong University-University of Adelaide Joint Centre for Agriculture and Health, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Wanqi Liang
- Joint International Research Laboratory of Metabolic and Developmental Sciences, Shanghai Jiao Tong University-University of Adelaide Joint Centre for Agriculture and Health, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Dabing Zhang
- University of Adelaide-Shanghai Jiao Tong University Joint Laboratory for Plant Science and Breeding, School of Agriculture, Food, and Wine, University of Adelaide, Waite Campus, Urrbrae, South Australia 5064, Australia
- Joint International Research Laboratory of Metabolic and Developmental Sciences, Shanghai Jiao Tong University-University of Adelaide Joint Centre for Agriculture and Health, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China
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17
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Bibeau JP, Kingsley JL, Furt F, Tüzel E, Vidali L. F-Actin Mediated Focusing of Vesicles at the Cell Tip Is Essential for Polarized Growth. PLANT PHYSIOLOGY 2018; 176:352-363. [PMID: 28972078 PMCID: PMC5761772 DOI: 10.1104/pp.17.00753] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2017] [Accepted: 09/26/2017] [Indexed: 05/18/2023]
Abstract
F-actin has been shown to be essential for tip growth in an array of plant models, including Physcomitrella patens One hypothesis is that diffusion can transport secretory vesicles, while actin plays a regulatory role during secretion. Alternatively, it is possible that actin-based transport is necessary to overcome vesicle transport limitations to sustain secretion. Therefore, a quantitative analysis of diffusion, secretion kinetics, and cell geometry is necessary to clarify the role of actin in polarized growth. Using fluorescence recovery after photobleaching analysis, we first show that secretory vesicles move toward and accumulate at the tip in an actin-dependent manner. We then depolymerized F-actin to decouple vesicle diffusion from actin-mediated transport and measured the diffusion coefficient and concentration of vesicles. Using these values, we constructed a theoretical diffusion-based model for growth, demonstrating that with fast-enough vesicle fusion kinetics, diffusion could support normal cell growth rates. We further refined our model to explore how experimentally extrapolated vesicle fusion kinetics and the size of the secretion zone limit diffusion-based growth. This model predicts that diffusion-mediated growth is dependent on the size of the region of exocytosis at the tip and that diffusion-based growth would be significantly slower than normal cell growth. To further explore the size of the secretion zone, we used a cell wall degradation enzyme cocktail and determined that the secretion zone is smaller than 6 μm in diameter at the tip. Taken together, our results highlight the requirement for active transport in polarized growth and provide important insight into vesicle secretion during tip growth.
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Affiliation(s)
- Jeffrey P Bibeau
- Department of Biology and Biotechnology, Worcester Polytechnic Institute, Worcester, Massachusetts 01609
| | - James L Kingsley
- Department of Physics, Worcester Polytechnic Institute, Worcester, Massachusetts 01609
| | - Fabienne Furt
- Department of Biology and Biotechnology, Worcester Polytechnic Institute, Worcester, Massachusetts 01609
| | - Erkan Tüzel
- Department of Physics, Worcester Polytechnic Institute, Worcester, Massachusetts 01609
| | - Luis Vidali
- Department of Biology and Biotechnology, Worcester Polytechnic Institute, Worcester, Massachusetts 01609
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18
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Oscillatory fungal cell growth. Fungal Genet Biol 2017; 110:10-14. [PMID: 29229585 DOI: 10.1016/j.fgb.2017.12.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2017] [Revised: 11/26/2017] [Accepted: 12/06/2017] [Indexed: 12/20/2022]
Abstract
Cells are dynamic systems, the state of which undergoes constant alteration that results in morphological changes and movement. Many dynamic cellular processes that appear continuous are driven by underlying mechanisms that oscillate with distinct periods. For example eukaryotic cells do not grow continuously, but rather by pulsed extension of the periphery. Stepwise cell extension at the hyphal tips of several filamentous fungi was discovered 20 years ago, but only a few molecular details of the mechanism have been clarified since then. A recent study has provided evidence for correlations among intracellular Ca2+ levels, actin assembly, exocytosis and cell extension in growing hyphal tips. This suggests that pulsed Ca2+ influxes coordinate the temporal control of actin assembly and exocytosis, which results in stepwise cell extension. The coordinated oscillation of these machineries are likely to be ubiquitous among all eukaryotes. Indeed, intracellular Ca2+ levels and/or actin polymerization oscillate in mammalian and plant cells. This review summarizes the mechanisms of oscillation in several systems.
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19
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Lipowczan M, Pietruszka M. Frequency-associated transition from single-cell asynchronous motion to monotonic growth. J Biol Phys 2017; 43:461-470. [PMID: 28900825 PMCID: PMC5696300 DOI: 10.1007/s10867-017-9462-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2016] [Accepted: 07/21/2017] [Indexed: 10/18/2022] Open
Abstract
This paper presents a Fourier analysis of the Ortega equation that examines the growth dynamics of plants, specifically the pollen tubes or non-meristematic zones of elongating coleoptiles. A frequency-induced transition from highly nonlinear (periodical) growth-like the one observed in pollen tubes-to monotonically ascending and asymptotically saturated (sigmoid-like) growth, which is anticipated within the framework of a 'two-fluid model', is shown. A dynamic phase diagram is calculated and presented in the form of a live video clip.
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Affiliation(s)
- Marcin Lipowczan
- Faculty of Biology and Environment Protection, Biophysics and Morphogenesis of Plants, University of Silesia, Jagiellońska 28, 40032, Katowice, Poland
| | - Mariusz Pietruszka
- Faculty of Biology and Environment Protection, Plant Physiology, University of Silesia, Jagiellońska 28, 40032, Katowice, Poland.
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20
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Hu C, Munglani G, Vogler H, Ndinyanka Fabrice T, Shamsudhin N, Wittel FK, Ringli C, Grossniklaus U, Herrmann HJ, Nelson BJ. Characterization of size-dependent mechanical properties of tip-growing cells using a lab-on-chip device. LAB ON A CHIP 2016; 17:82-90. [PMID: 27883138 DOI: 10.1039/c6lc01145d] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Quantification of mechanical properties of tissues, living cells, and cellular components is crucial for the modeling of plant developmental processes such as mechanotransduction. Pollen tubes are tip-growing cells that provide an ideal system to study the mechanical properties at the single cell level. In this article, a lab-on-a-chip (LOC) device is developed to quantitatively measure the biomechanical properties of lily (Lilium longiflorum) pollen tubes. A single pollen tube is fixed inside the microfluidic chip at a specific orientation and subjected to compression by a soft membrane. By comparing the deformation of the pollen tube at a given external load (compressibility) and the effect of turgor pressure on the tube diameter (stretch ratio) with finite element modeling, its mechanical properties are determined. The turgor pressure and wall stiffness of the pollen tubes are found to decrease considerably with increasing initial diameter of the pollen tubes. This observation supports the hypothesis that tip-growth is regulated by a delicate balance between turgor pressure and wall stiffness. The LOC device is modular and adaptable to a variety of cells that exhibit tip-growth, allowing for the straightforward measurement of mechanical properties.
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Affiliation(s)
- Chengzhi Hu
- Institute of Robotics and Intelligent Systems, ETH Zurich, Tannenstrasse 3, CH-8092 Zurich, Switzerland.
| | - Gautam Munglani
- Computational Physics for Engineering Materials, Institute for Building Materials, ETH Zurich, Stefano-Franscini-Platz 3, CH-8093 Zurich, Switzerland
| | - Hannes Vogler
- Institute of Plant and Microbial Biology & Zurich-Basel Plant Science Center, University of Zurich, Zollikerstrasse 107, CH-8008, Zurich, Switzerland
| | - Tohnyui Ndinyanka Fabrice
- Institute of Plant and Microbial Biology & Zurich-Basel Plant Science Center, University of Zurich, Zollikerstrasse 107, CH-8008, Zurich, Switzerland
| | - Naveen Shamsudhin
- Institute of Robotics and Intelligent Systems, ETH Zurich, Tannenstrasse 3, CH-8092 Zurich, Switzerland.
| | - Falk K Wittel
- Computational Physics for Engineering Materials, Institute for Building Materials, ETH Zurich, Stefano-Franscini-Platz 3, CH-8093 Zurich, Switzerland
| | - Christoph Ringli
- Institute of Plant and Microbial Biology & Zurich-Basel Plant Science Center, University of Zurich, Zollikerstrasse 107, CH-8008, Zurich, Switzerland
| | - Ueli Grossniklaus
- Institute of Plant and Microbial Biology & Zurich-Basel Plant Science Center, University of Zurich, Zollikerstrasse 107, CH-8008, Zurich, Switzerland
| | - Hans J Herrmann
- Computational Physics for Engineering Materials, Institute for Building Materials, ETH Zurich, Stefano-Franscini-Platz 3, CH-8093 Zurich, Switzerland
| | - Bradley J Nelson
- Institute of Robotics and Intelligent Systems, ETH Zurich, Tannenstrasse 3, CH-8092 Zurich, Switzerland.
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21
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Kopittke PM, Menzies NW, Wang P, Blamey FPC. Kinetics and nature of aluminium rhizotoxic effects: a review. JOURNAL OF EXPERIMENTAL BOTANY 2016; 67:4451-67. [PMID: 27302129 DOI: 10.1093/jxb/erw233] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Acid soils with elevated levels of soluble aluminium (Al) comprise ~40% of the world's arable land, but there remains much uncertainty regarding the mechanisms by which Al is rhizotoxic. This review examines the kinetics of the toxic effects of Al on the root elongation rate (RER), its effects on root tissues, and its location at a subcellular level. Depending upon the concentration and plant species, soluble Al decreases the RER in a median time of 73min, but in as little as 5min in soybean. This is initially due to a decreased rate at which cells expand anisotropically in the elongation zone. Thereafter, rhizodermal and outer cortical cells rupture through decreased cell wall relaxation. It is in this region where most Al accumulates in the apoplast. Subsequently, Al impacts root growth at a subcellular level through adverse effects on the plasma membrane (PM), cytoplasm, and nucleus. At the PM, Al alters permeability, fluidity, and integrity in as little as 0.5h, whilst it also depolarizes the PM and reduces H(+)-ATPase activity. The Al potentially crosses the PM within 0.5h where it is able to bind to the nucleus and inhibit cell division; sequestration within the vacuole is required to reduce the toxic effects of Al within the cytoplasm. This review demonstrates the increasing evidence of the importance of the initial Al-induced inhibition of wall loosening, but there is evidence also of the deleterious effects of Al on other cellular processes which are important for long-term root growth and function.
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Affiliation(s)
- Peter M Kopittke
- The University of Queensland, School of Agriculture and Food Sciences, St Lucia, Queensland 4072, Australia
| | - Neal W Menzies
- The University of Queensland, School of Agriculture and Food Sciences, St Lucia, Queensland 4072, Australia
| | - Peng Wang
- The University of Queensland, School of Agriculture and Food Sciences, St Lucia, Queensland 4072, Australia
| | - F Pax C Blamey
- The University of Queensland, School of Agriculture and Food Sciences, St Lucia, Queensland 4072, Australia
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22
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Zhang F, Jin X, Wang L, Li S, Wu S, Cheng C, Zhang T, Guo W. A Cotton Annexin Affects Fiber Elongation and Secondary Cell Wall Biosynthesis Associated with Ca2+ Influx, ROS Homeostasis, and Actin Filament Reorganization. PLANT PHYSIOLOGY 2016; 171:1750-70. [PMID: 27255486 PMCID: PMC4936584 DOI: 10.1104/pp.16.00597] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2016] [Accepted: 06/01/2016] [Indexed: 05/23/2023]
Abstract
Annexins play pivotal roles in a variety of cellular processes as well as in fiber development; however, the functional mechanisms of their activities are unclear. Here, an annexin gene that is preferentially expressed in fibers, GhFAnnxA, was found to be significantly associated with various cotton (Gossypium hirsutum) fiber traits. Transgenic analysis demonstrated that GhFAnnxA affected cotton fiber elongation and was involved in secondary cell wall (SCW) biosynthesis. Functional studies demonstrated that GhFAnnxA may act as a Ca(2+) conductance regulator and that reactive oxygen species (ROS) produced by Rbohs in a Ca(2+)-dependent manner may determine fiber elongation caused by elevated intracellular turgor and cell wall loosening. However, excessive hydrogen peroxide (H2O2) inhibited cotton fiber elongation in vitro. We speculate that a positive feedback loop involving ROS and Ca(2+) is regulated by GhCDPK1 and regulates fiber cell elongation. Furthermore, the convergence of actin filaments is altered by their interaction with GhFAnnxA, and this also may contribute to fiber elongation. Moreover, GhFAnnxA may affect SCW biosynthesis through changes in cell wall components caused by an increase in H2O2 levels. These results not only provide new insights into the signaling pathways of GhFAnnxA in fiber development but also clarify the role of ROS in fiber development.
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Affiliation(s)
- Feng Zhang
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Nanjing 210095, Jiangsu Province, People's Republic of China
| | - Xuanxiang Jin
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Nanjing 210095, Jiangsu Province, People's Republic of China
| | - Like Wang
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Nanjing 210095, Jiangsu Province, People's Republic of China
| | - Shufen Li
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Nanjing 210095, Jiangsu Province, People's Republic of China
| | - Shuang Wu
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Nanjing 210095, Jiangsu Province, People's Republic of China
| | - Chaoze Cheng
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Nanjing 210095, Jiangsu Province, People's Republic of China
| | - Tianzhen Zhang
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Nanjing 210095, Jiangsu Province, People's Republic of China
| | - Wangzhen Guo
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Nanjing 210095, Jiangsu Province, People's Republic of China
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23
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Williams JH, Edwards JA, Ramsey AJ. Economy, efficiency, and the evolution of pollen tube growth rates. AMERICAN JOURNAL OF BOTANY 2016; 103:471-483. [PMID: 26936897 DOI: 10.3732/ajb.1500264] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2015] [Accepted: 10/08/2015] [Indexed: 06/05/2023]
Abstract
PREMISE Pollen tube growth rate (PTGR) is an important aspect of male gametophyte performance because of its central role in the fertilization process. Theory suggests that under intense competition, PTGRs should evolve to be faster, especially if PTGR accurately reflects gametophyte quality. Oddly, we know remarkably little about how effectively the work of tube construction is translated to elongation (growth and growth rate). Here we test the prediction that pollen tubes grow equally efficiently by comparing the scaling of wall production rate (WPR) to PTGR in three water lilies that flower concurrently: Nymphaea odorata, Nuphar advena and Brasenia schreberi. METHODS Single-donor pollinations on flower or carpel pairs were fixed just after pollen germination (time A) and 45 min later (time B). Mean PTGR was calculated as the average increase in tube length over that growth period. Tube circumferences (C) and wall thicknesses (W) were measured at time B. For each donor, WPR = mean (C × W) × mean PTGR. KEY RESULTS Within species, pollen tubes maintained a constant WPR to PTGR ratio, but species had significantly different ratios. N. odorata and N. advena had similar PTGRs, but for any given PTGR, they had the lowest and highest WPRs, respectively. CONCLUSIONS We showed that growth rate efficiencies evolved by changes in the volume of wall material used for growth and in how that material was partitioned between lateral and length dimensions. The economics of pollen tube growth are determined by tube design, which is consequent on trade-offs between efficient growth and other pollen tube functions.
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Affiliation(s)
- Joseph H Williams
- Department of Ecology and Evolutionary Biology, University of Tennessee, Knoxville, Tennessee 37996 USA
| | - Jacob A Edwards
- Department of Ecology and Evolutionary Biology, University of Tennessee, Knoxville, Tennessee 37996 USA
| | - Adam J Ramsey
- Department of Ecology and Evolutionary Biology, University of Tennessee, Knoxville, Tennessee 37996 USA
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24
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Kohorn BD, Hoon D, Minkoff BB, Sussman MR, Kohorn SL. Rapid Oligo-Galacturonide Induced Changes in Protein Phosphorylation in Arabidopsis. Mol Cell Proteomics 2016; 15:1351-9. [PMID: 26811356 DOI: 10.1074/mcp.m115.055368] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2015] [Indexed: 11/06/2022] Open
Abstract
The wall-associated kinases (WAKs)(1)are receptor protein kinases that bind to long polymers of cross-linked pectin in the cell wall. These plasma-membrane-associated protein kinases also bind soluble pectin fragments called oligo-galacturonides (OGs) released from the wall after pathogen attack and damage. WAKs are required for cell expansion during development but bind water soluble OGs generated from walls with a higher affinity than the wall-associated polysaccharides. OGs activate a WAK-dependent, distinct stress-like response pathway to help plants resist pathogen attack. In this report, a quantitative mass-spectrometric-based phosphoproteomic analysis was used to identify Arabidopsis cellular events rapidly induced by OGsin planta Using N(14/)N(15)isotopicin vivometabolic labeling, we screened 1,000 phosphoproteins for rapid OG-induced changes and found 50 proteins with increased phosphorylation, while there were none that decreased significantly. Seven of the phosphosites within these proteins overlap with those altered by another signaling molecule plants use to indicate the presence of pathogens (the bacterial "elicitor" peptide Flg22), indicating distinct but overlapping pathways activated by these two types of chemicals. Genetic analysis of genes encoding 10 OG-specific and two Flg22/OG-induced phosphoproteins reveals that null mutations in eight proteins compromise the OG response. These phosphorylated proteins with genetic evidence supporting their role in the OG response include two cytoplasmic kinases, two membrane-associated scaffold proteins, a phospholipase C, a CDPK, an unknown cadmium response protein, and a motor protein. Null mutants in two proteins, the putative scaffold protein REM1.3, and a cytoplasmic receptor like kinase ROG2, enhance and suppress, respectively, a dominantWAKallele. Altogether, the results of these chemical and genetic experiments reveal the identity of several phosphorylated proteins involved in the kinase/phosphatase-mediated signaling pathway initiated by cell wall changes.
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Affiliation(s)
- Bruce D Kohorn
- From the ‡Biology Department, Bowdoin College, Brunswick, ME, 04011;
| | - Divya Hoon
- From the ‡Biology Department, Bowdoin College, Brunswick, ME, 04011
| | | | - Michael R Sussman
- §Department of Biochemistry, University of Wisconsin, Madison, WI 53706
| | - Susan L Kohorn
- From the ‡Biology Department, Bowdoin College, Brunswick, ME, 04011
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25
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Krupinski P, Bozorg B, Larsson A, Pietra S, Grebe M, Jönsson H. A Model Analysis of Mechanisms for Radial Microtubular Patterns at Root Hair Initiation Sites. FRONTIERS IN PLANT SCIENCE 2016; 7:1560. [PMID: 27840629 PMCID: PMC5083785 DOI: 10.3389/fpls.2016.01560] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2016] [Accepted: 10/04/2016] [Indexed: 05/12/2023]
Abstract
Plant cells have two main modes of growth generating anisotropic structures. Diffuse growth where whole cell walls extend in specific directions, guided by anisotropically positioned cellulose fibers, and tip growth, with inhomogeneous addition of new cell wall material at the tip of the structure. Cells are known to regulate these processes via molecular signals and the cytoskeleton. Mechanical stress has been proposed to provide an input to the positioning of the cellulose fibers via cortical microtubules in diffuse growth. In particular, a stress feedback model predicts a circumferential pattern of fibers surrounding apical tissues and growing primordia, guided by the anisotropic curvature in such tissues. In contrast, during the initiation of tip growing root hairs, a star-like radial pattern has recently been observed. Here, we use detailed finite element models to analyze how a change in mechanical properties at the root hair initiation site can lead to star-like stress patterns in order to understand whether a stress-based feedback model can also explain the microtubule patterns seen during root hair initiation. We show that two independent mechanisms, individually or combined, can be sufficient to generate radial patterns. In the first, new material is added locally at the position of the root hair. In the second, increased tension in the initiation area provides a mechanism. Finally, we describe how a molecular model of Rho-of-plant (ROP) GTPases activation driven by auxin can position a patch of activated ROP protein basally along a 2D root epidermal cell plasma membrane, paving the way for models where mechanical and molecular mechanisms cooperate in the initial placement and outgrowth of root hairs.
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Affiliation(s)
- Pawel Krupinski
- Computational Biology and Biological Physics, Department of Astronomy and Theoretical Physics, Lund UniversityLund, Sweden
- *Correspondence: Pawel Krupinski
| | - Behruz Bozorg
- Computational Biology and Biological Physics, Department of Astronomy and Theoretical Physics, Lund UniversityLund, Sweden
| | - André Larsson
- Computational Biology and Biological Physics, Department of Astronomy and Theoretical Physics, Lund UniversityLund, Sweden
| | - Stefano Pietra
- Department of Plant Physiology, Umeå Plant Science Centre, Umeå UniversityUmeå, Sweden
| | - Markus Grebe
- Department of Plant Physiology, Umeå Plant Science Centre, Umeå UniversityUmeå, Sweden
- Institute of Biochemistry and Biology, Plant Physiology, University of PotsdamPotsdam, Germany
| | - Henrik Jönsson
- Computational Biology and Biological Physics, Department of Astronomy and Theoretical Physics, Lund UniversityLund, Sweden
- Sainsbury Laboratory, University of CambridgeCambridge, UK
- Department of Applied Mathematics and Theoretical Physics, University of CambridgeCambridge, UK
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Abstract
The pectin matrix of the angiosperm cell wall is regulated in both synthesis and modification and greatly influences the direction and extent of cell growth. Pathogens, herbivory and mechanical stresses all influence this pectin matrix and consequently plant form and function. The cell wall-associated kinases (WAKs) bind to pectin and regulate cell expansion or stress responses depending upon the state of the pectin. This review explores the WAKs in the context of cell wall biology and signal transduction pathways.
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Affiliation(s)
- Bruce D Kohorn
- Department of Biology, Bowdoin College, Brunswick, ME 04011, USA
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Kopittke PM, Moore KL, Lombi E, Gianoncelli A, Ferguson BJ, Blamey FPC, Menzies NW, Nicholson TM, McKenna BA, Wang P, Gresshoff PM, Kourousias G, Webb RI, Green K, Tollenaere A. Identification of the primary lesion of toxic aluminum in plant roots. PLANT PHYSIOLOGY 2015; 167:1402-11. [PMID: 25670815 PMCID: PMC4378153 DOI: 10.1104/pp.114.253229] [Citation(s) in RCA: 107] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/05/2014] [Accepted: 02/07/2015] [Indexed: 05/19/2023]
Abstract
Despite the rhizotoxicity of aluminum (Al) being identified over 100 years ago, there is still no consensus regarding the mechanisms whereby root elongation rate is initially reduced in the approximately 40% of arable soils worldwide that are acidic. We used high-resolution kinematic analyses, molecular biology, rheology, and advanced imaging techniques to examine soybean (Glycine max) roots exposed to Al. Using this multidisciplinary approach, we have conclusively shown that the primary lesion of Al is apoplastic. In particular, it was found that 75 µm Al reduced root growth after only 5 min (or 30 min at 30 µm Al), with Al being toxic by binding to the walls of outer cells, which directly inhibited their loosening in the elongation zone. An alteration in the biosynthesis and distribution of ethylene and auxin was a second, slower effect, causing both a transient decrease in the rate of cell elongation after 1.5 h but also a longer term gradual reduction in the length of the elongation zone. These findings show the importance of focusing on traits related to cell wall composition as well as mechanisms involved in wall loosening to overcome the deleterious effects of soluble Al.
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Affiliation(s)
- Peter M Kopittke
- Schools of Agriculture and Food Sciences (P.M.K., B.J.F., F.P.C.B., N.W.M., B.A.M., P.W., P.M.G., A.T.) andChemical Engineering (T.M.N.) andCentres for Integrative Legume Research (B.J.F., P.M.G., A.T.) andMicroscopy and Microanalysis (R.I.W., K.G.), University of Queensland, St. Lucia, Queensland 4072, Australia;Department of Materials, University of Oxford, Oxford OX1 3PH, United Kingdom (K.L.M.);Centre for Environmental Risk Assessment and Remediation, University of South Australia, Mawson Lakes, South Australia 5095, Australia (E.L.); andTwinMic Beamline, Elettra-Sincrotrone Trieste, 34149 Trieste-Basovizza, Italy (A.G., G.K.)
| | - Katie L Moore
- Schools of Agriculture and Food Sciences (P.M.K., B.J.F., F.P.C.B., N.W.M., B.A.M., P.W., P.M.G., A.T.) andChemical Engineering (T.M.N.) andCentres for Integrative Legume Research (B.J.F., P.M.G., A.T.) andMicroscopy and Microanalysis (R.I.W., K.G.), University of Queensland, St. Lucia, Queensland 4072, Australia;Department of Materials, University of Oxford, Oxford OX1 3PH, United Kingdom (K.L.M.);Centre for Environmental Risk Assessment and Remediation, University of South Australia, Mawson Lakes, South Australia 5095, Australia (E.L.); andTwinMic Beamline, Elettra-Sincrotrone Trieste, 34149 Trieste-Basovizza, Italy (A.G., G.K.)
| | - Enzo Lombi
- Schools of Agriculture and Food Sciences (P.M.K., B.J.F., F.P.C.B., N.W.M., B.A.M., P.W., P.M.G., A.T.) andChemical Engineering (T.M.N.) andCentres for Integrative Legume Research (B.J.F., P.M.G., A.T.) andMicroscopy and Microanalysis (R.I.W., K.G.), University of Queensland, St. Lucia, Queensland 4072, Australia;Department of Materials, University of Oxford, Oxford OX1 3PH, United Kingdom (K.L.M.);Centre for Environmental Risk Assessment and Remediation, University of South Australia, Mawson Lakes, South Australia 5095, Australia (E.L.); andTwinMic Beamline, Elettra-Sincrotrone Trieste, 34149 Trieste-Basovizza, Italy (A.G., G.K.)
| | - Alessandra Gianoncelli
- Schools of Agriculture and Food Sciences (P.M.K., B.J.F., F.P.C.B., N.W.M., B.A.M., P.W., P.M.G., A.T.) andChemical Engineering (T.M.N.) andCentres for Integrative Legume Research (B.J.F., P.M.G., A.T.) andMicroscopy and Microanalysis (R.I.W., K.G.), University of Queensland, St. Lucia, Queensland 4072, Australia;Department of Materials, University of Oxford, Oxford OX1 3PH, United Kingdom (K.L.M.);Centre for Environmental Risk Assessment and Remediation, University of South Australia, Mawson Lakes, South Australia 5095, Australia (E.L.); andTwinMic Beamline, Elettra-Sincrotrone Trieste, 34149 Trieste-Basovizza, Italy (A.G., G.K.)
| | - Brett J Ferguson
- Schools of Agriculture and Food Sciences (P.M.K., B.J.F., F.P.C.B., N.W.M., B.A.M., P.W., P.M.G., A.T.) andChemical Engineering (T.M.N.) andCentres for Integrative Legume Research (B.J.F., P.M.G., A.T.) andMicroscopy and Microanalysis (R.I.W., K.G.), University of Queensland, St. Lucia, Queensland 4072, Australia;Department of Materials, University of Oxford, Oxford OX1 3PH, United Kingdom (K.L.M.);Centre for Environmental Risk Assessment and Remediation, University of South Australia, Mawson Lakes, South Australia 5095, Australia (E.L.); andTwinMic Beamline, Elettra-Sincrotrone Trieste, 34149 Trieste-Basovizza, Italy (A.G., G.K.)
| | - F Pax C Blamey
- Schools of Agriculture and Food Sciences (P.M.K., B.J.F., F.P.C.B., N.W.M., B.A.M., P.W., P.M.G., A.T.) andChemical Engineering (T.M.N.) andCentres for Integrative Legume Research (B.J.F., P.M.G., A.T.) andMicroscopy and Microanalysis (R.I.W., K.G.), University of Queensland, St. Lucia, Queensland 4072, Australia;Department of Materials, University of Oxford, Oxford OX1 3PH, United Kingdom (K.L.M.);Centre for Environmental Risk Assessment and Remediation, University of South Australia, Mawson Lakes, South Australia 5095, Australia (E.L.); andTwinMic Beamline, Elettra-Sincrotrone Trieste, 34149 Trieste-Basovizza, Italy (A.G., G.K.)
| | - Neal W Menzies
- Schools of Agriculture and Food Sciences (P.M.K., B.J.F., F.P.C.B., N.W.M., B.A.M., P.W., P.M.G., A.T.) andChemical Engineering (T.M.N.) andCentres for Integrative Legume Research (B.J.F., P.M.G., A.T.) andMicroscopy and Microanalysis (R.I.W., K.G.), University of Queensland, St. Lucia, Queensland 4072, Australia;Department of Materials, University of Oxford, Oxford OX1 3PH, United Kingdom (K.L.M.);Centre for Environmental Risk Assessment and Remediation, University of South Australia, Mawson Lakes, South Australia 5095, Australia (E.L.); andTwinMic Beamline, Elettra-Sincrotrone Trieste, 34149 Trieste-Basovizza, Italy (A.G., G.K.)
| | - Timothy M Nicholson
- Schools of Agriculture and Food Sciences (P.M.K., B.J.F., F.P.C.B., N.W.M., B.A.M., P.W., P.M.G., A.T.) andChemical Engineering (T.M.N.) andCentres for Integrative Legume Research (B.J.F., P.M.G., A.T.) andMicroscopy and Microanalysis (R.I.W., K.G.), University of Queensland, St. Lucia, Queensland 4072, Australia;Department of Materials, University of Oxford, Oxford OX1 3PH, United Kingdom (K.L.M.);Centre for Environmental Risk Assessment and Remediation, University of South Australia, Mawson Lakes, South Australia 5095, Australia (E.L.); andTwinMic Beamline, Elettra-Sincrotrone Trieste, 34149 Trieste-Basovizza, Italy (A.G., G.K.)
| | - Brigid A McKenna
- Schools of Agriculture and Food Sciences (P.M.K., B.J.F., F.P.C.B., N.W.M., B.A.M., P.W., P.M.G., A.T.) andChemical Engineering (T.M.N.) andCentres for Integrative Legume Research (B.J.F., P.M.G., A.T.) andMicroscopy and Microanalysis (R.I.W., K.G.), University of Queensland, St. Lucia, Queensland 4072, Australia;Department of Materials, University of Oxford, Oxford OX1 3PH, United Kingdom (K.L.M.);Centre for Environmental Risk Assessment and Remediation, University of South Australia, Mawson Lakes, South Australia 5095, Australia (E.L.); andTwinMic Beamline, Elettra-Sincrotrone Trieste, 34149 Trieste-Basovizza, Italy (A.G., G.K.)
| | - Peng Wang
- Schools of Agriculture and Food Sciences (P.M.K., B.J.F., F.P.C.B., N.W.M., B.A.M., P.W., P.M.G., A.T.) andChemical Engineering (T.M.N.) andCentres for Integrative Legume Research (B.J.F., P.M.G., A.T.) andMicroscopy and Microanalysis (R.I.W., K.G.), University of Queensland, St. Lucia, Queensland 4072, Australia;Department of Materials, University of Oxford, Oxford OX1 3PH, United Kingdom (K.L.M.);Centre for Environmental Risk Assessment and Remediation, University of South Australia, Mawson Lakes, South Australia 5095, Australia (E.L.); andTwinMic Beamline, Elettra-Sincrotrone Trieste, 34149 Trieste-Basovizza, Italy (A.G., G.K.)
| | - Peter M Gresshoff
- Schools of Agriculture and Food Sciences (P.M.K., B.J.F., F.P.C.B., N.W.M., B.A.M., P.W., P.M.G., A.T.) andChemical Engineering (T.M.N.) andCentres for Integrative Legume Research (B.J.F., P.M.G., A.T.) andMicroscopy and Microanalysis (R.I.W., K.G.), University of Queensland, St. Lucia, Queensland 4072, Australia;Department of Materials, University of Oxford, Oxford OX1 3PH, United Kingdom (K.L.M.);Centre for Environmental Risk Assessment and Remediation, University of South Australia, Mawson Lakes, South Australia 5095, Australia (E.L.); andTwinMic Beamline, Elettra-Sincrotrone Trieste, 34149 Trieste-Basovizza, Italy (A.G., G.K.)
| | - George Kourousias
- Schools of Agriculture and Food Sciences (P.M.K., B.J.F., F.P.C.B., N.W.M., B.A.M., P.W., P.M.G., A.T.) andChemical Engineering (T.M.N.) andCentres for Integrative Legume Research (B.J.F., P.M.G., A.T.) andMicroscopy and Microanalysis (R.I.W., K.G.), University of Queensland, St. Lucia, Queensland 4072, Australia;Department of Materials, University of Oxford, Oxford OX1 3PH, United Kingdom (K.L.M.);Centre for Environmental Risk Assessment and Remediation, University of South Australia, Mawson Lakes, South Australia 5095, Australia (E.L.); andTwinMic Beamline, Elettra-Sincrotrone Trieste, 34149 Trieste-Basovizza, Italy (A.G., G.K.)
| | - Richard I Webb
- Schools of Agriculture and Food Sciences (P.M.K., B.J.F., F.P.C.B., N.W.M., B.A.M., P.W., P.M.G., A.T.) andChemical Engineering (T.M.N.) andCentres for Integrative Legume Research (B.J.F., P.M.G., A.T.) andMicroscopy and Microanalysis (R.I.W., K.G.), University of Queensland, St. Lucia, Queensland 4072, Australia;Department of Materials, University of Oxford, Oxford OX1 3PH, United Kingdom (K.L.M.);Centre for Environmental Risk Assessment and Remediation, University of South Australia, Mawson Lakes, South Australia 5095, Australia (E.L.); andTwinMic Beamline, Elettra-Sincrotrone Trieste, 34149 Trieste-Basovizza, Italy (A.G., G.K.)
| | - Kathryn Green
- Schools of Agriculture and Food Sciences (P.M.K., B.J.F., F.P.C.B., N.W.M., B.A.M., P.W., P.M.G., A.T.) andChemical Engineering (T.M.N.) andCentres for Integrative Legume Research (B.J.F., P.M.G., A.T.) andMicroscopy and Microanalysis (R.I.W., K.G.), University of Queensland, St. Lucia, Queensland 4072, Australia;Department of Materials, University of Oxford, Oxford OX1 3PH, United Kingdom (K.L.M.);Centre for Environmental Risk Assessment and Remediation, University of South Australia, Mawson Lakes, South Australia 5095, Australia (E.L.); andTwinMic Beamline, Elettra-Sincrotrone Trieste, 34149 Trieste-Basovizza, Italy (A.G., G.K.)
| | - Alina Tollenaere
- Schools of Agriculture and Food Sciences (P.M.K., B.J.F., F.P.C.B., N.W.M., B.A.M., P.W., P.M.G., A.T.) andChemical Engineering (T.M.N.) andCentres for Integrative Legume Research (B.J.F., P.M.G., A.T.) andMicroscopy and Microanalysis (R.I.W., K.G.), University of Queensland, St. Lucia, Queensland 4072, Australia;Department of Materials, University of Oxford, Oxford OX1 3PH, United Kingdom (K.L.M.);Centre for Environmental Risk Assessment and Remediation, University of South Australia, Mawson Lakes, South Australia 5095, Australia (E.L.); andTwinMic Beamline, Elettra-Sincrotrone Trieste, 34149 Trieste-Basovizza, Italy (A.G., G.K.)
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28
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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. FRONTIERS IN PLANT SCIENCE 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] [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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29
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Leroux C, Bouton S, Kiefer-Meyer MC, Fabrice TN, Mareck A, Guénin S, Fournet F, Ringli C, Pelloux J, Driouich A, Lerouge P, Lehner A, Mollet JC. PECTIN METHYLESTERASE48 is involved in Arabidopsis pollen grain germination. PLANT PHYSIOLOGY 2015; 167:367-80. [PMID: 25524442 PMCID: PMC4326738 DOI: 10.1104/pp.114.250928] [Citation(s) in RCA: 76] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2014] [Accepted: 12/16/2014] [Indexed: 05/18/2023]
Abstract
Germination of pollen grains is a crucial step in plant reproduction. However, the molecular mechanisms involved remain unclear. We investigated the role of PECTIN METHYLESTERASE48 (PME48), an enzyme implicated in the remodeling of pectins in Arabidopsis (Arabidopsis thaliana) pollen. A combination of functional genomics, gene expression, in vivo and in vitro pollen germination, immunolabeling, and biochemical analyses was used on wild-type and Atpme48 mutant plants. We showed that AtPME48 is specifically expressed in the male gametophyte and is the second most expressed PME in dry and imbibed pollen grains. Pollen grains from homozygous mutant lines displayed a significant delay in imbibition and germination in vitro and in vivo. Moreover, numerous pollen grains showed two tips emerging instead of one in the wild type. Immunolabeling and Fourier transform infrared analyses showed that the degree of methylesterification of the homogalacturonan was higher in pme48-/- pollen grains. In contrast, the PME activity was lower in pme48-/-, partly due to a reduction of PME48 activity revealed by zymogram. Interestingly, the wild-type phenotype was restored in pme48-/- with the optimum germination medium supplemented with 2.5 mm calcium chloride, suggesting that in the wild-type pollen, the weakly methylesterified homogalacturonan is a source of Ca(2+) necessary for pollen germination. Although pollen-specific PMEs are traditionally associated with pollen tube elongation, this study provides strong evidence that PME48 impacts the mechanical properties of the intine wall during maturation of the pollen grain, which, in turn, influences pollen grain germination.
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Affiliation(s)
- Christelle Leroux
- Laboratoire Glycobiologie et Matrice Extracellulaire, Normandie Université, Institute for Research and Innovation in Biomedicine, Végétal, Agronomie, Sol, et Innovation, 76821 Mont-Saint-Aignan, France (C.L., M.-C.K.-M., A.M., A.D., P.L., A.L., J.-C.M.);Unité Biologie des Plantes et Innovation (S.B., S.G., F.F., J.P.) and Centre de Ressources Régionales en Biologie Moléculaire (S.G.), Université de Picardie Jules Verne, 80039 Amiens, France; andInstitute of Plant Biology, University of Zürich, 8008 Zurich, Switzerland (T.N.F., C.R.)
| | - Sophie Bouton
- Laboratoire Glycobiologie et Matrice Extracellulaire, Normandie Université, Institute for Research and Innovation in Biomedicine, Végétal, Agronomie, Sol, et Innovation, 76821 Mont-Saint-Aignan, France (C.L., M.-C.K.-M., A.M., A.D., P.L., A.L., J.-C.M.);Unité Biologie des Plantes et Innovation (S.B., S.G., F.F., J.P.) and Centre de Ressources Régionales en Biologie Moléculaire (S.G.), Université de Picardie Jules Verne, 80039 Amiens, France; andInstitute of Plant Biology, University of Zürich, 8008 Zurich, Switzerland (T.N.F., C.R.)
| | - Marie-Christine Kiefer-Meyer
- Laboratoire Glycobiologie et Matrice Extracellulaire, Normandie Université, Institute for Research and Innovation in Biomedicine, Végétal, Agronomie, Sol, et Innovation, 76821 Mont-Saint-Aignan, France (C.L., M.-C.K.-M., A.M., A.D., P.L., A.L., J.-C.M.);Unité Biologie des Plantes et Innovation (S.B., S.G., F.F., J.P.) and Centre de Ressources Régionales en Biologie Moléculaire (S.G.), Université de Picardie Jules Verne, 80039 Amiens, France; andInstitute of Plant Biology, University of Zürich, 8008 Zurich, Switzerland (T.N.F., C.R.)
| | - Tohnyui Ndinyanka Fabrice
- Laboratoire Glycobiologie et Matrice Extracellulaire, Normandie Université, Institute for Research and Innovation in Biomedicine, Végétal, Agronomie, Sol, et Innovation, 76821 Mont-Saint-Aignan, France (C.L., M.-C.K.-M., A.M., A.D., P.L., A.L., J.-C.M.);Unité Biologie des Plantes et Innovation (S.B., S.G., F.F., J.P.) and Centre de Ressources Régionales en Biologie Moléculaire (S.G.), Université de Picardie Jules Verne, 80039 Amiens, France; andInstitute of Plant Biology, University of Zürich, 8008 Zurich, Switzerland (T.N.F., C.R.)
| | - Alain Mareck
- Laboratoire Glycobiologie et Matrice Extracellulaire, Normandie Université, Institute for Research and Innovation in Biomedicine, Végétal, Agronomie, Sol, et Innovation, 76821 Mont-Saint-Aignan, France (C.L., M.-C.K.-M., A.M., A.D., P.L., A.L., J.-C.M.);Unité Biologie des Plantes et Innovation (S.B., S.G., F.F., J.P.) and Centre de Ressources Régionales en Biologie Moléculaire (S.G.), Université de Picardie Jules Verne, 80039 Amiens, France; andInstitute of Plant Biology, University of Zürich, 8008 Zurich, Switzerland (T.N.F., C.R.)
| | - Stéphanie Guénin
- Laboratoire Glycobiologie et Matrice Extracellulaire, Normandie Université, Institute for Research and Innovation in Biomedicine, Végétal, Agronomie, Sol, et Innovation, 76821 Mont-Saint-Aignan, France (C.L., M.-C.K.-M., A.M., A.D., P.L., A.L., J.-C.M.);Unité Biologie des Plantes et Innovation (S.B., S.G., F.F., J.P.) and Centre de Ressources Régionales en Biologie Moléculaire (S.G.), Université de Picardie Jules Verne, 80039 Amiens, France; andInstitute of Plant Biology, University of Zürich, 8008 Zurich, Switzerland (T.N.F., C.R.)
| | - Françoise Fournet
- Laboratoire Glycobiologie et Matrice Extracellulaire, Normandie Université, Institute for Research and Innovation in Biomedicine, Végétal, Agronomie, Sol, et Innovation, 76821 Mont-Saint-Aignan, France (C.L., M.-C.K.-M., A.M., A.D., P.L., A.L., J.-C.M.);Unité Biologie des Plantes et Innovation (S.B., S.G., F.F., J.P.) and Centre de Ressources Régionales en Biologie Moléculaire (S.G.), Université de Picardie Jules Verne, 80039 Amiens, France; andInstitute of Plant Biology, University of Zürich, 8008 Zurich, Switzerland (T.N.F., C.R.)
| | - Christoph Ringli
- Laboratoire Glycobiologie et Matrice Extracellulaire, Normandie Université, Institute for Research and Innovation in Biomedicine, Végétal, Agronomie, Sol, et Innovation, 76821 Mont-Saint-Aignan, France (C.L., M.-C.K.-M., A.M., A.D., P.L., A.L., J.-C.M.);Unité Biologie des Plantes et Innovation (S.B., S.G., F.F., J.P.) and Centre de Ressources Régionales en Biologie Moléculaire (S.G.), Université de Picardie Jules Verne, 80039 Amiens, France; andInstitute of Plant Biology, University of Zürich, 8008 Zurich, Switzerland (T.N.F., C.R.)
| | - Jérôme Pelloux
- Laboratoire Glycobiologie et Matrice Extracellulaire, Normandie Université, Institute for Research and Innovation in Biomedicine, Végétal, Agronomie, Sol, et Innovation, 76821 Mont-Saint-Aignan, France (C.L., M.-C.K.-M., A.M., A.D., P.L., A.L., J.-C.M.);Unité Biologie des Plantes et Innovation (S.B., S.G., F.F., J.P.) and Centre de Ressources Régionales en Biologie Moléculaire (S.G.), Université de Picardie Jules Verne, 80039 Amiens, France; andInstitute of Plant Biology, University of Zürich, 8008 Zurich, Switzerland (T.N.F., C.R.)
| | - Azeddine Driouich
- Laboratoire Glycobiologie et Matrice Extracellulaire, Normandie Université, Institute for Research and Innovation in Biomedicine, Végétal, Agronomie, Sol, et Innovation, 76821 Mont-Saint-Aignan, France (C.L., M.-C.K.-M., A.M., A.D., P.L., A.L., J.-C.M.);Unité Biologie des Plantes et Innovation (S.B., S.G., F.F., J.P.) and Centre de Ressources Régionales en Biologie Moléculaire (S.G.), Université de Picardie Jules Verne, 80039 Amiens, France; andInstitute of Plant Biology, University of Zürich, 8008 Zurich, Switzerland (T.N.F., C.R.)
| | - Patrice Lerouge
- Laboratoire Glycobiologie et Matrice Extracellulaire, Normandie Université, Institute for Research and Innovation in Biomedicine, Végétal, Agronomie, Sol, et Innovation, 76821 Mont-Saint-Aignan, France (C.L., M.-C.K.-M., A.M., A.D., P.L., A.L., J.-C.M.);Unité Biologie des Plantes et Innovation (S.B., S.G., F.F., J.P.) and Centre de Ressources Régionales en Biologie Moléculaire (S.G.), Université de Picardie Jules Verne, 80039 Amiens, France; andInstitute of Plant Biology, University of Zürich, 8008 Zurich, Switzerland (T.N.F., C.R.)
| | - Arnaud Lehner
- Laboratoire Glycobiologie et Matrice Extracellulaire, Normandie Université, Institute for Research and Innovation in Biomedicine, Végétal, Agronomie, Sol, et Innovation, 76821 Mont-Saint-Aignan, France (C.L., M.-C.K.-M., A.M., A.D., P.L., A.L., J.-C.M.);Unité Biologie des Plantes et Innovation (S.B., S.G., F.F., J.P.) and Centre de Ressources Régionales en Biologie Moléculaire (S.G.), Université de Picardie Jules Verne, 80039 Amiens, France; andInstitute of Plant Biology, University of Zürich, 8008 Zurich, Switzerland (T.N.F., C.R.)
| | - Jean-Claude Mollet
- Laboratoire Glycobiologie et Matrice Extracellulaire, Normandie Université, Institute for Research and Innovation in Biomedicine, Végétal, Agronomie, Sol, et Innovation, 76821 Mont-Saint-Aignan, France (C.L., M.-C.K.-M., A.M., A.D., P.L., A.L., J.-C.M.);Unité Biologie des Plantes et Innovation (S.B., S.G., F.F., J.P.) and Centre de Ressources Régionales en Biologie Moléculaire (S.G.), Université de Picardie Jules Verne, 80039 Amiens, France; andInstitute of Plant Biology, University of Zürich, 8008 Zurich, Switzerland (T.N.F., C.R.)
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Höfte H. The yin and yang of cell wall integrity control: brassinosteroid and FERONIA signaling. PLANT & CELL PHYSIOLOGY 2015; 56:224-31. [PMID: 25481004 DOI: 10.1093/pcp/pcu182] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Understanding how developmental and environmental signals control plant cell expansion requires an intimate knowledge of the architecture of the primary cell wall and the chemo-rheological processes that underlie cell wall relaxation. In this review I discuss recent findings that reveal a more prominent role than previously suspected for covalent bonds and pectin cross-links in primary cell wall architecture. In addition, genetic studies have uncovered a role for receptor kinases in the control of cell wall homeostasis in growing cells. The emerging view is that, upon cell wall disruption, compensatory changes are induced in the cell wall through the interplay between the brassinosteroid signaling module, which positively regulates wall extensibility and receptor kinases of the CrRLKL1 family, which may act as negative regulators of cell wall stiffness. These findings lift the tip of the veil of a complex signaling network allowing normal homeostasis in walls of growing cells but also crisis management under stress conditions.
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Affiliation(s)
- Herman Höfte
- INRA, Institut Jean-Pierre Bourgin, UMR 1318, ERL CNRS 3559, Saclay Plant Sciences, RD10, F-78026 Versailles, France AgroParisTech, Institut Jean-Pierre Bourgin, UMR 1318, ERL CNRS 3559, Saclay Plant Sciences, RD10, F-78026 Versailles, France
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31
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Chen LY, Shi DQ, Zhang WJ, Tang ZS, Liu J, Yang WC. The Arabidopsis alkaline ceramidase TOD1 is a key turgor pressure regulator in plant cells. Nat Commun 2015; 6:6030. [PMID: 25591940 PMCID: PMC4309442 DOI: 10.1038/ncomms7030] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2014] [Accepted: 12/04/2014] [Indexed: 11/09/2022] Open
Abstract
Turgor pressure plays pivotal roles in the growth and movement of walled cells that make up plants and fungi. However, the molecular mechanisms regulating turgor pressure and the coordination between turgor pressure and cell wall remodelling for cell growth remain poorly understood. Here, we report the characterization of Arabidopsis TurgOr regulation Defect 1 (TOD1), which is preferentially expressed in pollen tubes and silique guard cells. We demonstrate that TOD1 is a Golgi-localized alkaline ceramidase. tod1 mutant pollen tubes have higher turgor than wild type and show growth retardation both in pistils and in agarose medium. In addition, tod1 guard cells are insensitive to abscisic acid (ABA)-induced stomatal closure, whereas sphingosine-1-phosphate, a putative downstream component of ABA signalling and product of alkaline ceramidases, promotes closure in both wild type and tod1. Our data suggest that TOD1 acts in turgor pressure regulation in both guard cells and pollen tubes.
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Affiliation(s)
- Li-Yu Chen
- 1] State Key Laboratory of Molecular Developmental Biology and National Center for Plant Gene Research (Beijing), Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China [2] University of Chinese Academy of Sciences, Beijing 100049, China
| | - Dong-Qiao Shi
- State Key Laboratory of Molecular Developmental Biology and National Center for Plant Gene Research (Beijing), Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Wen-Juan Zhang
- 1] State Key Laboratory of Molecular Developmental Biology and National Center for Plant Gene Research (Beijing), Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China [2] University of Chinese Academy of Sciences, Beijing 100049, China
| | - Zuo-Shun Tang
- State Key Laboratory of Molecular Developmental Biology and National Center for Plant Gene Research (Beijing), Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Jie Liu
- State Key Laboratory of Molecular Developmental Biology and National Center for Plant Gene Research (Beijing), Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Wei-Cai Yang
- 1] State Key Laboratory of Molecular Developmental Biology and National Center for Plant Gene Research (Beijing), Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China [2] Collaborative Innovation Center for Genetics and Development, Fudan University, Shanghai 200433, China
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32
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Hepler PK, Winship LJ. The pollen tube clear zone: clues to the mechanism of polarized growth. JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2015; 57:79-92. [PMID: 25431342 DOI: 10.1111/jipb.12315] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2014] [Accepted: 11/24/2014] [Indexed: 05/08/2023]
Abstract
Pollen tubes usually exhibit a prominent region at their apex called the "clear zone" because it lacks light refracting amyloplasts. A robust, long clear zone often associates with fast growing pollen tubes, and thus serves as an indicator of pollen tube health. Nevertheless we do not understand how it arises or how it is maintained. Here we review the structure of the clear zone, and attempt to explain the factors that contribute to its formation. While amyloplasts and vacuolar elements are excluded from the clear zone, virtually all other organelles are present including secretory vesicles, mitochondria, Golgi dictyosomes, and the endoplasmic reticulum (ER). Secretory vesicles aggregate into an inverted cone appressed against the apical plasma membrane. ER elements move nearly to the extreme apex, whereas mitochondria and Golgi dictyosomes move less far forward. The cortical actin fringe assumes a central position in the control of clear zone formation and maintenance, given its role in generating cytoplasmic streaming. Other likely factors include the tip-focused calcium gradient, the apical pH gradient, the influx of water, and a host of signaling factors (small G-proteins). We think that the clear zone is an emergent property that depends on the interaction of several factors crucial for polarized growth.
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Affiliation(s)
- Peter K Hepler
- Biology Department, University of Massachusetts, Amherst, Massachusetts, 01003, USA
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33
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Worden N, Esteve VE, Domozych DS, Drakakaki G. Using chemical genomics to study cell wall formation and cell growth in Arabidopsis thaliana and Penium margaritaceum. Methods Mol Biol 2015; 1242:23-39. [PMID: 25408440 DOI: 10.1007/978-1-4939-1902-4_2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The cell wall is directly involved in cell growth, and its ability to loosen and rearrange allows for cell expansion through the existing turgor pressure. Thus, information on cell wall deposition and rearrangement can provide insights into the overall plant growth. This chapter describes two methods that can be used to evaluate cell expansion (1) in the model plant Arabidopsis thaliana and (2) the model alga Penium margaritaceum. These methods are further used to screen for small molecules that induce cell growth phenotypic changes affecting cell wall. Identification of such small molecules is beneficial due to their posttranslational mechanism of action that can be controlled in a temporal and spatial manner. Chemical genomics has the ability to overcome issues of genetic redundancy and lethality, which can hinder traditional genetic methods. The identification of small molecules in these screens will provide useful information on plant cell wall biology and overall plant growth.
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Affiliation(s)
- N Worden
- Department of Plant Sciences, University of California Davis, One Shields Avenue, Davis, CA, 95616, USA
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34
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Abstract
The pollen tube represents a model system for the study of tip growth, and the root provides a valuable system to study gene and signalling networks in plants. In the present article, using the two systems as examples, we discuss how to elucidate the regulation of complex signalling systems in plant cells. First, we discuss how hormones and related genes in plant root development form a complex interacting network, and their activities are interdependent. Therefore their roles in root development must be analysed as an integrated system, and elucidation of the regulation of each component requires the adaptation of a novel modelling methodology: regulation analysis. Secondly, hydrodynamics, cell wall and ion dynamics are all important properties that regulate plant cell growth. We discuss how regulation analysis can be applied to study the regulation of hydrodynamics, cell wall and ion dynamics, using pollen tube growth as a model system. Finally, we discuss future prospects for elucidating the regulation of complex signalling systems in plant cells.
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35
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Biagini G, Faleri C, Cresti M, Cai G. Sucrose concentration in the growth medium affects the cell wall composition of tobacco pollen tubes. PLANT REPRODUCTION 2014; 27:129-44. [PMID: 25015837 DOI: 10.1007/s00497-014-0246-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2014] [Accepted: 07/01/2014] [Indexed: 06/03/2023]
Abstract
The cell wall of pollen tubes is organized in both spatial and temporal order to allow the pollen tube to grow according to external conditions. The deposition of methyl-esterified and acid pectins in addition to callose/cellulose occurs according to a series of temporally succeeding events. In this work, we attempted to determine how the composition of the external growth medium (in terms of osmolarity) could affect the deposition of cell wall components. Pollen tubes of tobacco were grown in a hypotonic medium and then analyzed for the distribution of pectins and callose/cellulose [as well as for the distribution of the enzyme callose synthase (CALS)]. The data indicate that pollen tubes grown in a hypotonic medium show changes of the initial growth rate followed by modification of the deposition of acid pectins and, to a lesser extent, of CALS. These observations indicate that, under the osmolarity determined by the growth medium, pollen tubes adapt their cell wall to the changing conditions of growth.
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36
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Rounds CM, Hepler PK, Winship LJ. The apical actin fringe contributes to localized cell wall deposition and polarized growth in the lily pollen tube. PLANT PHYSIOLOGY 2014; 166:139-51. [PMID: 25037212 PMCID: PMC4149702 DOI: 10.1104/pp.114.242974] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/14/2014] [Accepted: 07/08/2014] [Indexed: 05/19/2023]
Abstract
In lily (Lilium formosanum) pollen tubes, pectin, a major component of the cell wall, is delivered through regulated exocytosis. The targeted transport and secretion of the pectin-containing vesicles may be controlled by the cortical actin fringe at the pollen tube apex. Here, we address the role of the actin fringe using three different inhibitors of growth: brefeldin A, latrunculin B, and potassium cyanide. Brefeldin A blocks membrane trafficking and inhibits exocytosis in pollen tubes; it also leads to the degradation of the actin fringe and the formation of an aggregate of filamentous actin at the base of the clear zone. Latrunculin B, which depolymerizes filamentous actin, markedly slows growth but allows focused pectin deposition to continue. Of note, the locus of deposition shifts frequently and correlates with changes in the direction of growth. Finally, potassium cyanide, an electron transport chain inhibitor, briefly stops growth while causing the actin fringe to completely disappear. Pectin deposition continues but lacks focus, instead being delivered in a wide arc across the pollen tube tip. These data support a model in which the actin fringe contributes to the focused secretion of pectin to the apical cell wall and, thus, to the polarized growth of the pollen tube.
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Affiliation(s)
- Caleb M Rounds
- Department of Biology, University of Massachusetts, Amherst, Massachusetts 01003 (C.M.R., P.K.H.); andSchool of Natural Science, Hampshire College, Amherst, Massachusetts 01002 (L.J.W.)
| | - Peter K Hepler
- Department of Biology, University of Massachusetts, Amherst, Massachusetts 01003 (C.M.R., P.K.H.); andSchool of Natural Science, Hampshire College, Amherst, Massachusetts 01002 (L.J.W.)
| | - Lawrence J Winship
- Department of Biology, University of Massachusetts, Amherst, Massachusetts 01003 (C.M.R., P.K.H.); andSchool of Natural Science, Hampshire College, Amherst, Massachusetts 01002 (L.J.W.)
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37
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Liu J, Hussey PJ. Dissecting the regulation of pollen tube growth by modeling the interplay of hydrodynamics, cell wall and ion dynamics. FRONTIERS IN PLANT SCIENCE 2014; 5:392. [PMID: 25157262 PMCID: PMC4127481 DOI: 10.3389/fpls.2014.00392] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2014] [Accepted: 07/22/2014] [Indexed: 05/30/2023]
Abstract
Hydrodynamics, cell wall and ion dynamics are all important properties that regulate pollen tube growth. Currently, the two main pollen tube growth models, the cell wall model and the hydrodynamic model do not appear to be reconcilable. Here we develop an integrative model for pollen tube growth and show that our model reproduces key experimental observations: (1) that the hypertonic condition leads to a much longer oscillatory period and that the hypotonic condition halves the oscillatory period; (2) that oscillations in turgor are experimentally undetectable; (3) that increasing the extracellular calcium concentration or decreasing the pH decreases the growth oscillatory amplitude; (4) that knockout of Raba4d, a member of the Rab family of small GTPase proteins, decreases pollen tube length after germination for 24 h. Using the model generated here, we reveal that (1) when cell wall extensibility is large, pollen tube may sustain growth at different volume changes and maintain relatively stable turgor; (2) turgor increases if cell wall extensibility decreases; (3) increasing turgor due to decrease in osmolarity in the media, although very small, increases volume change. However, increasing turgor due to decrease in cell wall extensibility decreases volume change. In this way regulation of pollen tube growth by turgor is context dependent. By changing the osmolarity in the media, the main regulatory points are extracellular osmolarity for water flow and turgor for the volume encompassed by the cell wall. However, if the viscosity of cell wall changes, the main regulatory points are turgor for water flow and wall extensibility for the volume encompassed by the cell wall. The novel methodology developed here reveals the underlying context-dependent regulatory principle of pollen tube growth.
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Affiliation(s)
- Junli Liu
- School of Biological and Biomedical Sciences, Durham UniversityDurham, UK
| | - Patrick J. Hussey
- School of Biological and Biomedical Sciences, Durham UniversityDurham, UK
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38
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Haduch-Sendecka A, Pietruszka M, Zajdel P. Power spectrum, growth velocities and cross-correlations of longitudinal and transverse oscillations of individual Nicotiana tabacum pollen tube. PLANTA 2014; 240:263-76. [PMID: 24817588 PMCID: PMC4107278 DOI: 10.1007/s00425-014-2083-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2014] [Accepted: 04/17/2014] [Indexed: 05/25/2023]
Abstract
We report on our results concerning growth rate and oscillation modes of the individual pollen tube apex. The observed volumetric growth and growth rate periodicity in the longitudinal (axial) direction are accompanied by transverse oscillations with similar frequencies but higher energies than the axial modes. Examination of the time-domain coherence between oscillations in mutually perpendicular directions revealed minimal energy dissipation in the unperturbed (isotonic) case, opposite to the two remaining cases (hypertonic, hypotonic) with notable correlations. We conjecture that the minimal energy loss is therefore optimal in the natural growth conditions. The longitudinal growth velocity is also found to be the fastest in the unperturbed case. As a result, the isolated system (pollen tube tip) is conserving energy by transforming it from elastic potential energy of extending apical wall to the kinetic energy of periodical motion. The energy dissipation is found to be about 20 % smaller in axial direction than in lateral one, indicating that the main energy consumption is dedicated to the elongation. We further observe that the hypertonic spectrum is shifted towards lower and the hypotonic towards higher frequencies with respect to the isotonic spectrum. In consequence, the turgor pressure inside the growing cell influences monotonically the frequency of both modes of oscillations. The calculated power spectrum seen as a measure of the overall energy efficiency of tip growth under hypertonic, hypotonic and isotonic conditions implies that the biochemistry has been fine tuned to be optimal under normal growth conditions, which is the developmental implication of this work. A simple theoretical extension of the Ortega equation is derived and analysed with respect to its contribution to power spectrum. We show that the plastic term, related to the effective turgor pressure, with maximum contribution at frequency f = 0 is responsible for the steady growth. In turn, the elastic contribution dependent on the time derivative of pressure fluctuations tends to move the system into oscillatory mode (f > 0). None of those mechanisms is privileged over another. The coupling mechanism is naturally generated through a convolution of those two terms and will decide about the overall character of the growth for each particular case.
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Affiliation(s)
- Aleksandra Haduch-Sendecka
- Laboratory of Plant Physiology, Faculty of Biology and Environment Protection, University of Silesia, ul. Jagiellońska 28, 40032 Katowice, Poland
| | - Mariusz Pietruszka
- Laboratory of Plant Physiology, Faculty of Biology and Environment Protection, University of Silesia, ul. Jagiellońska 28, 40032 Katowice, Poland
| | - Paweł Zajdel
- Institute of Physics, University of Silesia, ul. Uniwersytecka 4, 40007 Katowice, Poland
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Kohorn BD, Kohorn SL, Saba NJ, Martinez VM. Requirement for pectin methyl esterase and preference for fragmented over native pectins for wall-associated kinase-activated, EDS1/PAD4-dependent stress response in Arabidopsis. J Biol Chem 2014; 289:18978-86. [PMID: 24855660 DOI: 10.1074/jbc.m114.567545] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
The wall-associated kinases (WAKs) have a cytoplasmic protein kinase domain that spans the plasma membrane and binds pectin in the extracellular matrix of plants. WAKs are required for cell expansion during Arabidopsis seedling development but are also an integral part of the response to pathogens and stress that present oligogalacturonides (OGs), which subsequently bind to WAKs and activate a MPK6 (mitogen-activated protein kinase)-dependent pathway. It was unclear how WAKs distinguish native pectin polymers and OGs to activate one or the other of these two pathways. A dominant allele of WAK2 constitutively activates the stress response, and we show here that the effect is dependent upon EDS1 and PAD4, transcriptional activators involved in the pathogen response. Moreover, the WAK2 dominant allele is suppressed by a null allele of a pectin methyl esterase (PME3) whose activity normally leads to cross-linking of pectins in the cell wall. Although OGs activate a transcriptional response in wild type, the response is enhanced in a pme3/pme3 null, consistent with a competition by OG and native polymers for activation of WAKs. This provides a plausible mechanism for WAKs to distinguish an expansion from a stress pathway.
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Affiliation(s)
- Bruce D Kohorn
- From the Department of Biology, Bowdoin College, Brunswick, Maine 04011
| | - Susan L Kohorn
- From the Department of Biology, Bowdoin College, Brunswick, Maine 04011
| | - Nicholas J Saba
- From the Department of Biology, Bowdoin College, Brunswick, Maine 04011
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40
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Wudick MM, Luu DT, Tournaire-Roux C, Sakamoto W, Maurel C. Vegetative and sperm cell-specific aquaporins of Arabidopsis highlight the vacuolar equipment of pollen and contribute to plant reproduction. PLANT PHYSIOLOGY 2014; 164:1697-706. [PMID: 24492334 PMCID: PMC3982734 DOI: 10.1104/pp.113.228700] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
The water and nutrient status of pollen is crucial to plant reproduction. Pollen grains of Arabidopsis (Arabidopsis thaliana) contain a large vegetative cell and two smaller sperm cells. Pollen grains express AtTIP1;3 and AtTIP5;1, two members of the Tonoplast Intrinsic Protein subfamily of aquaporins. To address the spatial and temporal expression pattern of the two homologs, C-terminal fusions of AtTIP1;3 and AtTIP5;1 with green fluorescent protein and mCherry, respectively, were expressed in transgenic Arabidopsis under the control of their native promoter. Confocal laser scanning microscopy revealed that AtTIP1;3 and AtTIP5;1 are specific for the vacuoles of the vegetative and sperm cells, respectively. The tonoplast localization of AtTIP5;1 was established by reference to fluorescent protein markers for the mitochondria and vacuoles of sperm and vegetative cells and is at variance with the claim that AtTIP5;1 is localized in vegetative cell mitochondria. AtTIP1;3-green fluorescent protein and AtTIP5;1-mCherry showed concomitant expression, from first pollen mitosis up to pollen tube penetration in the ovule, thereby revealing the dynamics of vacuole morphology in maturating and germinating pollen. Transfer DNA insertion mutants for either AtTIP1;3 or AtTIP5;1 showed no apparent growth phenotype and had no significant defect in male transmission of the mutated alleles. By contrast, a double knockout displayed an abnormal rate of barren siliques, this phenotype being more pronounced under limited water or nutrient supply. The overall data indicate that vacuoles of vegetative and sperm cells functionally interact and contribute to male fertility in adverse environmental conditions.
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No stress! Relax! Mechanisms governing growth and shape in plant cells. Int J Mol Sci 2014; 15:5094-114. [PMID: 24663059 PMCID: PMC3975442 DOI: 10.3390/ijms15035094] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2013] [Revised: 03/03/2014] [Accepted: 03/04/2014] [Indexed: 12/15/2022] Open
Abstract
The mechanisms through which plant cells control growth and shape are the result of the coordinated action of many events, notably cell wall stress relaxation and turgor-driven expansion. The scalar nature of turgor pressure would drive plant cells to assume spherical shapes; however, this is not the case, as plant cells show an amazing variety of morphologies. Plant cell walls are dynamic structures that can display alterations in matrix polysaccharide composition and concentration, which ultimately affect the wall deformation rate. The wide varieties of plant cell shapes, spanning from elongated cylinders (as pollen tubes) and jigsaw puzzle-like epidermal cells, to very long fibres and branched stellate leaf trichomes, can be understood if the underlying mechanisms regulating wall biosynthesis and cytoskeletal dynamics are addressed. This review aims at gathering the available knowledge on the fundamental mechanisms regulating expansion, growth and shape in plant cells by putting a special emphasis on the cell wall-cytoskeleton system continuum. In particular, we discuss from a molecular point of view the growth mechanisms characterizing cell types with strikingly different geometries and describe their relationship with primary walls. The purpose, here, is to provide the reader with a comprehensive overview of the multitude of events through which plant cells manage to expand and control their final shapes.
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42
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Lu Y, Kermicle JL, Evans MMS. Genetic and cellular analysis of cross-incompatibility in Zea mays. PLANT REPRODUCTION 2014; 27:19-29. [PMID: 24193168 DOI: 10.1007/s00497-013-0236-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/07/2013] [Accepted: 10/21/2013] [Indexed: 05/10/2023]
Abstract
Three genetic systems conferring cross-incompatibility have been described in Zea mays: Teosinte crossing barrier1-strong (Tcb1-s) found in teosinte, and Gametophyte factor1-strong (Ga1-s) and Ga2-s found in maize and teosinte. The reproductive barrier between maize and some weedy teosintes is controlled by the Tcb1-s locus. Multi-generation inheritance experiments on two independent Tcb1-s lineages show that the Tcb1-s barrier is unstable in some maize lines. Reciprocal crosses between Tcb1-s tester plants and three recombinants in the Tcb1-s mapping region demonstrate that the Tcb1-s haplotype contains separable male and female components. In vivo assays of the dynamics of pollen tube growth and pollen tube morphology during rejection of incompatible pollen in silks carrying the Tcb1-s, Ga1-s, or Ga2-s barriers showed that, in all three, pollen tube growth is slower than in compatible crosses at early stages and had ceased by 24 h after pollination. In all three crossing barrier systems, incompatible pollen tubes have clustered callose plugs in contrast to pollen tubes of compatible crosses. Incompatible pollen tubes growing in the Tcb1-s, Ga1-s, and Ga2-s silks have different morphologies: straight, curved, and kinked, respectively. The distinct morphologies suggest that these crossing barriers block incompatible pollen through different mechanisms. This study lays the foundation for cloning the Tcb1 genes and provides clues about the cellular mechanisms involved in pollen rejection in the Tcb1-s, Ga1-s, and Ga2-s crossing barriers.
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Affiliation(s)
- Yongxian Lu
- Department of Plant Biology, Carnegie Institute for Science, Stanford, CA, 94305, USA
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43
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Pietruszka M. Pressure-induced cell wall instability and growth oscillations in pollen tubes. PLoS One 2013; 8:e75803. [PMID: 24260097 PMCID: PMC3833986 DOI: 10.1371/journal.pone.0075803] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2013] [Accepted: 08/18/2013] [Indexed: 11/19/2022] Open
Abstract
In the seed plants, the pollen tube is a cellular extension that serves as a conduit through which male gametes are transported to complete fertilization of the egg cell. It consists of a single elongated cell which exhibits characteristic oscillations in growth rate until it finally bursts, completing its function. The mechanism behind the periodic character of the growth has not been fully understood. In this paper we show that the mechanism of pressure--induced symmetry frustration occurring in the wall at the transition-perimeter between the cylindrical and approximately hemispherical parts of the growing pollen tube, together with the addition of cell wall material, is sufficient to release and sustain mechanical self-oscillations and cell extension. At the transition zone, where symmetry frustration occurs and one cannot distinguish either of the involved symmetries, a kind of 'superposition state' appears where either single or both symmetry(ies) can be realized by the system. We anticipate that testifiable predictions made by the model (f is proportional to √P) may deliver, after calibration, a new tool to estimate turgor pressure P from oscillation frequency f of the periodically growing cell. Since the mechanical principles apply to all turgor regulated walled cells including those of plant, fungal and bacterial origin, the relevance of this work is not limited to the case of the pollen tube.
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Affiliation(s)
- Mariusz Pietruszka
- Faculty of Biology and Environment Protection, University of Silesia, Katowice, Poland
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44
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Basic rules for polarised cell growth. J Theor Biol 2013; 336:44-51. [DOI: 10.1016/j.jtbi.2013.06.039] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2013] [Revised: 06/25/2013] [Accepted: 06/27/2013] [Indexed: 12/11/2022]
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Luo J, Ma N, Pei H, Chen J, Li J, Gao J. A DELLA gene, RhGAI1, is a direct target of EIN3 and mediates ethylene-regulated rose petal cell expansion via repressing the expression of RhCesA2. JOURNAL OF EXPERIMENTAL BOTANY 2013; 64:5075-84. [PMID: 24014864 PMCID: PMC3830487 DOI: 10.1093/jxb/ert296] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Ethylene plays an important role in organ growth. In Arabidopsis, ethylene can inhibit root elongation by stabilizing DELLA proteins. In previous work, it was found that ethylene suppressed cell expansion in rose petals, and five unisequences of DELLA genes are induced by ethylene. However, the mechanism of transcriptional regulation of DELLA genes by ethylene is still not clear. The results showed that the expression of RhGAI1 was induced in both ethylene-treated and ETR gene-silenced rose petals, and the promoter activity of RhGAI1 was strongly induced by RhEIN3-3 in Arabidopsis protoplasts. What is more, RhEIN3-3 could bind to the promoter of RhGAI1 directly in an electrophoretic mobility shift assay (EMSA). Cell expansion was suppressed in RhGAI1-Δ17-overexpressed Arabidopsis petals and promoted in RhGAI1-silenced rose petals. Moreover, in RhGAI1-silenced petals, the expression of nine cell expansion-related genes was clearly changed, and RhGAI1 can bind to the promoter of RhCesA2 in an EMSA. These results suggested that RhGAI1 was regulated by ethylene at the transcriptional level, and RhGAI1 was a direct target of RhEIN3-3. Also, RhGAI1 was shown to be involved in cell expansion partially through regulating the expression of cell expansion-related genes. Furthermore, RhCesA2 was a direct target of RhGAI1. This work uncovers the transcriptional regulation of RhGAI1 by ethylene and provides a better understanding of how ethylene regulates petal expansion in roses.
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Affiliation(s)
| | | | | | | | | | - Junping Gao
- * To whom correspondence should be addressed. E-mail:
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Nezhad AS, Packirisamy M, Bhat R, Geitmann A. In Vitro Study of Oscillatory Growth Dynamics of Camellia Pollen Tubes in Microfluidic Environment. IEEE Trans Biomed Eng 2013; 60:3185-93. [DOI: 10.1109/tbme.2013.2270914] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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47
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Sanati Nezhad A, Geitmann A. The cellular mechanics of an invasive lifestyle. JOURNAL OF EXPERIMENTAL BOTANY 2013; 64:4709-28. [PMID: 24014865 DOI: 10.1093/jxb/ert254] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Invasive behaviour is the hallmark of a variety of cell types of animal, plant, and fungal origin. Here we review the purpose and mechanism of invasive growth and migration. The focus is on the physical principles governing the process, the source of invasive force, and the cellular mechanism by which the cell penetrates the substrate. The current experimental methods for measuring invasive force and the modelling approaches for studying invasive behaviour are explained, and future experimental strategies are proposed.
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Affiliation(s)
- Amir Sanati Nezhad
- McGill University and Génome Québec Innovation Centre, Biomedical Engineering Department, McGill University, Montreal, Canada
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48
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Gutermuth T, Lassig R, Portes MT, Maierhofer T, Romeis T, Borst JW, Hedrich R, Feijó JA, Konrad KR. Pollen tube growth regulation by free anions depends on the interaction between the anion channel SLAH3 and calcium-dependent protein kinases CPK2 and CPK20. THE PLANT CELL 2013; 25:4525-43. [PMID: 24280384 PMCID: PMC3875734 DOI: 10.1105/tpc.113.118463] [Citation(s) in RCA: 99] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2013] [Revised: 10/17/2013] [Accepted: 10/31/2013] [Indexed: 05/18/2023]
Abstract
Apical growth in pollen tubes (PTs) is associated with the presence of tip-focused ion gradients and fluxes, implying polar localization or regulation of the underlying transporters. The molecular identity and regulation of anion transporters in PTs is unknown. Here we report a negative gradient of cytosolic anion concentration focused on the tip, in negative correlation with the cytosolic Ca(2+) concentration. We hypothesized that a possible link between these two ions is based on the presence of Ca(2+)-dependent protein kinases (CPKs). We characterized anion channels and CPK transcripts in PTs and analyzed their localization. Yellow fluorescent protein (YFP) tagging of a homolog of SLOW ANION CHANNEL-ASSOCIATED1 (SLAH3:YFP) was widespread along PTs, but, in accordance with the anion efflux, CPK2/CPK20/CPK17/CPK34:YFP fluorescence was strictly localized at the tip plasma membrane. Expression of SLAH3 with either CPK2 or CPK20 (but not CPK17/CPK34) in Xenopus laevis oocytes elicited S-type anion channel currents. Interaction of SLAH3 with CPK2/CPK20 (but not CPK17/CPK34) was confirmed by Förster-resonance energy transfer fluorescence lifetime microscopy in Arabidopsis thaliana mesophyll protoplasts and bimolecular fluorescence complementation in living PTs. Compared with wild-type PTs, slah3-1 and slah3-2 as well as cpk2-1 cpk20-2 PTs had reduced anion currents. Double mutant cpk2-1 cpk20-2 and slah3-1 PTs had reduced extracellular anion fluxes at the tip. Our studies provide evidence for a Ca(2+)-dependent CPK2/CPK20 regulation of the anion channel SLAH3 to regulate PT growth.
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Affiliation(s)
- Timo Gutermuth
- Gulbenkian Institute of Science, P-2780-156 Oeiras, Portugal
- Department of Botany I, Julius-Von-Sachs Institute for Biosciences, University of Wuerzburg, 97082 Wuerzburg, Germany
| | - Roman Lassig
- Department of Plant Biochemistry, Dahlem Centre of Plant Sciences, Free University of Berlin, 14195 Berlin, Germany
| | | | - Tobias Maierhofer
- Department of Botany I, Julius-Von-Sachs Institute for Biosciences, University of Wuerzburg, 97082 Wuerzburg, Germany
| | - Tina Romeis
- Department of Plant Biochemistry, Dahlem Centre of Plant Sciences, Free University of Berlin, 14195 Berlin, Germany
| | - Jan-Willem Borst
- Laboratory of Biochemistry and Microspectroscopy Centre, Wageningen University, 6708 Wageningen, The Netherlands
| | - Rainer Hedrich
- Department of Botany I, Julius-Von-Sachs Institute for Biosciences, University of Wuerzburg, 97082 Wuerzburg, Germany
| | - José A. Feijó
- Gulbenkian Institute of Science, P-2780-156 Oeiras, Portugal
- Faculty of Sciences, Department of Plant Biology, University of Lisbon, P-1749-016 Lisbon, Portugal
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, Maryland 20742-5815
| | - Kai R. Konrad
- Gulbenkian Institute of Science, P-2780-156 Oeiras, Portugal
- Department of Botany I, Julius-Von-Sachs Institute for Biosciences, University of Wuerzburg, 97082 Wuerzburg, Germany
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Barbacci A, Lahaye M, Magnenet V. Another brick in the cell wall: biosynthesis dependent growth model. PLoS One 2013; 8:e74400. [PMID: 24066142 PMCID: PMC3774806 DOI: 10.1371/journal.pone.0074400] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2013] [Accepted: 08/01/2013] [Indexed: 11/19/2022] Open
Abstract
Expansive growth of plant cell is conditioned by the cell wall ability to extend irreversibly. This process is possible if (i) a tensile stress is developed in the cell wall due to the coupling effect between turgor pressure and the modulation of its mechanical properties through enzymatic and physicochemical reactions and if (ii) new cell wall elements can be synthesized and assembled to the existing wall. In other words, expansive growth is the result of coupling effects between mechanical, thermal and chemical energy. To have a better understanding of this process, models must describe the interplay between physical or mechanical variable with biological events. In this paper we propose a general unified and theoretical framework to model growth in function of energy forms and their coupling. This framework is based on irreversible thermodynamics. It is then applied to model growth of the internodal cell of Chara corallina modulated by changes in pressure and temperature. The results describe accurately cell growth in term of length increment but also in term of cell pectate biosynthesis and incorporation to the expanding wall. Moreover, the classical growth model based on Lockhart's equation such as the one proposed by Ortega, appears as a particular and restrictive case of the more general growth equation developed in this paper.
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Affiliation(s)
- Adelin Barbacci
- Biopolymers Interactions Assembly UR 1268 (BIA), Institut National de la Recherche Agronomique (INRA), Nantes, France
- * E-mail: (AB); (VM)
| | - Marc Lahaye
- Biopolymers Interactions Assembly UR 1268 (BIA), Institut National de la Recherche Agronomique (INRA), Nantes, France
| | - Vincent Magnenet
- Laboratoire des sciences de l'ingnieur, de l'informatique et de l'imagerie (ICube), Université de Strasbourg, UMR CNRS 7357, Illkirch, France
- * E-mail: (AB); (VM)
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50
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Hepler PK, Rounds CM, Winship LJ. Control of cell wall extensibility during pollen tube growth. MOLECULAR PLANT 2013; 6:998-1017. [PMID: 23770837 PMCID: PMC4043104 DOI: 10.1093/mp/sst103] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
In this review, we address the question of how the tip-growing pollen tube achieves its rapid rate of elongation while maintaining an intact cell wall. Although turgor is essential for growth to occur, the local expansion rate is controlled by local changes in the viscosity of the apical wall. We focus on several different structures and underlying processes that are thought to be major participants including exocytosis, the organization and activity of the actin cytoskeleton, calcium and proton physiology, and cellular energetics. We think that the actin cytoskeleton, in particular the apical cortical actin fringe, directs the flow of vesicles to the apical domain, where they fuse with the plasma membrane and contribute their contents to the expanding cell wall. While pH gradients, as generated by a proton-ATPase located on the plasma membrane along the side of the clear zone, may regulate rapid actin turnover and new polymerization in the fringe, the tip-focused calcium gradient biases secretion towards the polar axis. The recent data showing that exocytosis of new wall material precedes and predicts the process of cell elongation provide support for the idea that the intussusception of newly secreted pectin contributes to decreases in apical wall viscosity and to cell expansion. Other prime factors will be the localization and activity of the enzyme pectin methyl-esterase, and the chelation of calcium by pectic acids. Finally, we acknowledge a role for reactive oxygen species in the control of wall viscosity.
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Affiliation(s)
- Peter K Hepler
- Biology Department, University of Massachusetts, Amherst, MA 01003, USA.
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