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Zhang Q, Wang B, Kong X, Li K, Huang Y, Peng L, Chen L, Liu J, Yu Q, He J, Yang Y, Li X, Wang J. Knockout of cyclase-associated protein CAP1 confers tolerance towards salt and osmotic stress in Arabidopsis. JOURNAL OF PLANT PHYSIOLOGY 2023; 285:153978. [PMID: 37087999 DOI: 10.1016/j.jplph.2023.153978] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Revised: 03/30/2023] [Accepted: 03/31/2023] [Indexed: 05/03/2023]
Abstract
As a regulator of actin filament turnover, Arabidopsis thaliana CAP1 plays an important role in plant growth and development. Here, we analyzed the phenotypes of two Arabidopsis cap1 mutants: cap1-1 (a T-DNA insertion mutant) and Cas9-CAP1 (generated by CRISPR-Cas9 gene editing). Phenotypic analysis demonstrated that loss of CAP1 results in defects in seed germination and seedling morphology, with some seedlings exhibiting one or three cotyledons. The cap1-1 mutant took longer than the wild type to complete its life cycle, but its flowering time was normal, indicating that loss of CAP1 prolongs reproductive but not vegetative growth. Moreover, loss of CAP1 severely reduces seed production in self-pollinated plants, due to disruption of pollen tube elongation. RNA-seq and qRT-PCR analyses demonstrated that CAP1 may be involved in osmotic stress responses. Indeed, the cap1-1 mutant showed increased tolerance of salt and mannitol treatment, indicating that CAP1 plays a negative role in osmotic stress tolerance in Arabidopsis. Taken together, our results demonstrate that CAP1 functions not only in plant growth and development, but also in Arabidopsis responses to osmotic stress.
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Affiliation(s)
- Qian Zhang
- Key Laboratory of Bio-Resources and Eco-Environment of Ministry of Education, College of Life Sciences, State Key Laboratory of Hydraulics and Mountain River Engineering, Sichuan University, Chengdu, China
| | - Boya Wang
- Southwest University of Science and Technology, School of Life Science and Engineering, Mianyang, China
| | - Xiangge Kong
- Key Laboratory of Bio-Resources and Eco-Environment of Ministry of Education, College of Life Sciences, State Key Laboratory of Hydraulics and Mountain River Engineering, Sichuan University, Chengdu, China
| | - Kexuan Li
- Key Laboratory of Bio-Resources and Eco-Environment of Ministry of Education, College of Life Sciences, State Key Laboratory of Hydraulics and Mountain River Engineering, Sichuan University, Chengdu, China
| | - Yaling Huang
- Key Laboratory of Bio-Resources and Eco-Environment of Ministry of Education, College of Life Sciences, State Key Laboratory of Hydraulics and Mountain River Engineering, Sichuan University, Chengdu, China
| | - Lu Peng
- Key Laboratory of Bio-Resources and Eco-Environment of Ministry of Education, College of Life Sciences, State Key Laboratory of Hydraulics and Mountain River Engineering, Sichuan University, Chengdu, China
| | - Li Chen
- Key Laboratory of Bio-Resources and Eco-Environment of Ministry of Education, College of Life Sciences, State Key Laboratory of Hydraulics and Mountain River Engineering, Sichuan University, Chengdu, China
| | - Jiajia Liu
- Key Laboratory of Bio-Resources and Eco-Environment of Ministry of Education, College of Life Sciences, State Key Laboratory of Hydraulics and Mountain River Engineering, Sichuan University, Chengdu, China
| | - Qin Yu
- Key Laboratory of Bio-Resources and Eco-Environment of Ministry of Education, College of Life Sciences, State Key Laboratory of Hydraulics and Mountain River Engineering, Sichuan University, Chengdu, China
| | - Juan He
- Key Laboratory of Bio-Resources and Eco-Environment of Ministry of Education, College of Life Sciences, State Key Laboratory of Hydraulics and Mountain River Engineering, Sichuan University, Chengdu, China
| | - Yi Yang
- Key Laboratory of Bio-Resources and Eco-Environment of Ministry of Education, College of Life Sciences, State Key Laboratory of Hydraulics and Mountain River Engineering, Sichuan University, Chengdu, China
| | - Xiaoyi Li
- Key Laboratory of Bio-Resources and Eco-Environment of Ministry of Education, College of Life Sciences, State Key Laboratory of Hydraulics and Mountain River Engineering, Sichuan University, Chengdu, China
| | - Jianmei Wang
- Key Laboratory of Bio-Resources and Eco-Environment of Ministry of Education, College of Life Sciences, State Key Laboratory of Hydraulics and Mountain River Engineering, Sichuan University, Chengdu, China.
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Pratap Sahi V, Cifrová P, García-González J, Kotannal Baby I, Mouillé G, Gineau E, Müller K, Baluška F, Soukup A, Petrášek J, Schwarzerová K. Arabidopsis thaliana plants lacking the ARP2/3 complex show defects in cell wall assembly and auxin distribution. ANNALS OF BOTANY 2018; 122:777-789. [PMID: 29293873 PMCID: PMC6215044 DOI: 10.1093/aob/mcx178] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2017] [Accepted: 11/10/2017] [Indexed: 05/25/2023]
Abstract
BACKGROUND AND AIM The cytoskeleton plays an important role in the synthesis of plant cell walls. Both microtubules and actin cytoskeleton are known to be involved in the morphogenesis of plant cells through their role in cell wall building. The role of ARP2/3-nucleated actin cytoskeleton in the morphogenesis of cotyledon pavement cells has been described before. Seedlings of Arabidopsis mutants lacking a functional ARP2/3 complex display specific cell wall-associated defects. METHODS In three independent Arabidopsis mutant lines lacking subunits of the ARP2/3 complex, phenotypes associated with the loss of the complex were analysed throughout plant development. Organ size and anatomy, cell wall composition, and auxin distribution were investigated. KEY RESULTS ARP2/3-related phenotype is associated with changes in cell wall composition, and the phenotype is manifested especially in mature tissues. Cell walls of mature plants contain less cellulose and a higher amount of homogalacturonan, and display changes in cell wall lignification. Vascular bundles of mutant inflorescence stems show a changed pattern of AUX1-YFP expression. Plants lacking a functional ARP2/3 complex have decreased basipetal auxin transport. CONCLUSIONS The results suggest that the ARP2/3 complex has a morphogenetic function related to cell wall synthesis and auxin transport.
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Affiliation(s)
- Vaidurya Pratap Sahi
- Department of Experimental Plant Biology, Faculty of Science, Charles University, Viničná, Czech Republic
| | - Petra Cifrová
- Department of Experimental Plant Biology, Faculty of Science, Charles University, Viničná, Czech Republic
| | - Judith García-González
- Department of Experimental Plant Biology, Faculty of Science, Charles University, Viničná, Czech Republic
| | | | - Gregory Mouillé
- Institut Jean-Pierre Bourgin, INRA, AgroParisTech, CNRS, Université Paris-Saclay, Versailles, France
| | - Emilie Gineau
- Institut Jean-Pierre Bourgin, INRA, AgroParisTech, CNRS, Université Paris-Saclay, Versailles, France
| | - Karel Müller
- Institute of Experimental Botany, AS CR, Rozvojová, Czech Republic
| | - František Baluška
- Department of Plant Cell Biology, Institute of Cellular and Molecular Botany, University of Bonn, Kirschallee, Bonn, Germany
| | - Aleš Soukup
- Department of Experimental Plant Biology, Faculty of Science, Charles University, Viničná, Czech Republic
| | - Jan Petrášek
- Department of Experimental Plant Biology, Faculty of Science, Charles University, Viničná, Czech Republic
- Institute of Experimental Botany, AS CR, Rozvojová, Czech Republic
| | - Kateřina Schwarzerová
- Department of Experimental Plant Biology, Faculty of Science, Charles University, Viničná, Czech Republic
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Huang X, Maisch J, Nick P. Sensory role of actin in auxin-dependent responses of tobacco BY-2. JOURNAL OF PLANT PHYSIOLOGY 2017; 218:6-15. [PMID: 28763708 DOI: 10.1016/j.jplph.2017.07.011] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2017] [Revised: 07/13/2017] [Accepted: 07/14/2017] [Indexed: 05/09/2023]
Abstract
Polar auxin transport depends on the polar localization of auxin-efflux carriers. The cycling of these carriers between cell interior and plasma membrane depends on actin. The dynamic of actin not only affects auxin transport, but also changes the auxin-responsiveness. To study the potential link between auxin responsiveness and actin dynamics, we investigated developmental responses of the non-transformed BY-2 (Nicotiana tabacum L. cv Bright Yellow 2) cell line and the transgenic BY-2 strain GF11 (stably transformed BY-2 cells with a GFP-fimbrin actin-binding domain 2 construct). The developmental process was divided into three distinct stages: cell cycling, cell elongation and file disintegration. Several phenotypes were measured to monitor the cellular responses to different concentrations of exogenous natural auxin (Indole-3-acetic acid, IAA). We found that auxin stimulated and prolonged the mitotic activity, and delayed the exit from the proliferation phase. However, both responses were suppressed in the GF11 line. At the stationary phase of the cultivation cycle, auxin strongly accelerated the cell file disintegration. Interestingly, it was not suppressed but progressed to a more complete disintegration in the GF11 line. During the cultivation cycle, we also followed the organization of actin in the GF11 line and did not detect any significant difference in actin organization from untreated control or exogenous IAA treatment. Therefore, our findings indicate that the specific differences observed in the GF11 line must be linked with a function of actin that is not structural. It means that there is a sensory role of actin for auxin signaling.
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Affiliation(s)
- Xiang Huang
- Botanical Institute, Karlsruhe Institute of Technology, Fritz-Haber-Weg. 4, Gbd. 30.43, (5. OG), 76131 Karlsruhe, Germany.
| | - Jan Maisch
- Botanical Institute, Karlsruhe Institute of Technology, Fritz-Haber-Weg. 4, Gbd. 30.43, (5. OG), 76131 Karlsruhe, Germany.
| | - Peter Nick
- Botanical Institute, Karlsruhe Institute of Technology, Fritz-Haber-Weg. 4, Gbd. 30.43, (5. OG), 76131 Karlsruhe, Germany.
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Cheng ML, Lo SF, Hsiao AS, Hong YF, Yu SM, Ho THD. Ectopic Expression of WINDING 1 Leads to Asymmetrical Distribution of Auxin and a Spiral Phenotype in Rice. PLANT & CELL PHYSIOLOGY 2017; 58:1494-1506. [PMID: 28922746 DOI: 10.1093/pcp/pcx088] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/28/2017] [Accepted: 06/19/2017] [Indexed: 06/07/2023]
Abstract
Ectopic expression of the rice WINDING 1 (WIN1) gene leads to a spiral phenotype only in shoots but not in roots. Rice WIN1 belongs to a specific class of proteins in cereal plants containing a Bric-a-Brac/Tramtrack/Broad (BTB) complex, a non-phototropic hypocotyl 3 (NPH3) domain and a coiled-coil motif. The WIN1 protein is predominantly localized to the plasma membrane, but is also co-localized to plasmodesmata, where it exhibits a punctate pattern. It is observed that WIN1 is normally expressed in roots and the shoot-root junction, but not in the rest of shoots. In roots, WIN1 is largely localized to the apical and basal sides of cells. However, upon ectopic expression, WIN1 appears on the longitudinal sides of leaf sheath cells, correlated with the appearance of a spiral phenotype in shoots. Despite the spiral phenotype, WIN1-overexpressing plants exhibit a normal phototropic response. Although treatments with exogenous auxins or a polar auxin transport inhibitor do not alter the spiral phenotype, the excurvature side has a higher auxin concentration than the incurvature side. Furthermore, actin filaments are more prominent in the excurvature side than in the incurvature side, which correlates with cell size differences between these two sides. Interestingly, ectopic expression of WIN1 does not cause either unequal auxin distribution or actin filament differences in roots, so a spiral phenotype is not observed in roots. The action of WIN1 appears to be different from that of other proteins causing a spiral phenotype, and it is likely that WIN1 is involved in 1-N-naphthylphthalamic acid-insensitive plasmodesmata-mediated auxin transport.
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Affiliation(s)
- Ming-Lung Cheng
- Department of Life Sciences, National Cheng Kung University, Tainan 701, Taiwan, ROC
- Institute of Molecular Biology, Academia Sinica, Nankang, Taipei 115, Taiwan, ROC
| | - Shuen-Fang Lo
- Institute of Molecular Biology, Academia Sinica, Nankang, Taipei 115, Taiwan, ROC
- Agricultural Biotechnology Center, National Chung Hsing University, Taichung 402, Taiwan, ROC
| | - An-Shan Hsiao
- Institute of Plant and Microbial Biology, Academia Sinica, Nankang, Taipei 115, Taiwan, ROC
| | - Ya-Fang Hong
- Institute of Plant and Microbial Biology, Academia Sinica, Nankang, Taipei 115, Taiwan, ROC
| | - Su-May Yu
- Department of Life Sciences, National Cheng Kung University, Tainan 701, Taiwan, ROC
- Institute of Molecular Biology, Academia Sinica, Nankang, Taipei 115, Taiwan, ROC
- Agricultural Biotechnology Center, National Chung Hsing University, Taichung 402, Taiwan, ROC
- Department of Life Sciences, National Chung Hsing University, Taichung 402, Taiwan, ROC
| | - Tuan-Hua David Ho
- Department of Life Sciences, National Cheng Kung University, Tainan 701, Taiwan, ROC
- Agricultural Biotechnology Center, National Chung Hsing University, Taichung 402, Taiwan, ROC
- Institute of Plant and Microbial Biology, Academia Sinica, Nankang, Taipei 115, Taiwan, ROC
- Department of Life Sciences, National Chung Hsing University, Taichung 402, Taiwan, ROC
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Jin W, Zhou Q, Wei Y, Yang J, Hao F, Cheng Z, Guo H, Liu W. NtWRKY-R1, a Novel Transcription Factor, Integrates IAA and JA Signal Pathway under Topping Damage Stress in Nicotiana tabacum. FRONTIERS IN PLANT SCIENCE 2017; 8:2263. [PMID: 29379516 PMCID: PMC5775218 DOI: 10.3389/fpls.2017.02263] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2017] [Accepted: 12/27/2017] [Indexed: 05/14/2023]
Abstract
Topping damage can induce the nicotine synthesis in tobacco roots, which involves the activation of JA and auxin signal transduction. It remains unclear how these hormone signals are integrated to regulate nicotine synthesis. Here we isolated a transcription factor NtWRKY-R1 from the group IIe of WRKY family and it had strong negative correlation with the expression of putrescine N-methyltransferase, the key enzyme of nicotine synthesis pathway. NtWRKY-R1 was specifically and highly expressed in tobacco roots, and it contains two transcriptional activity domains in the N- and C-terminal. The promoter region of NtWRKY-R1 contains two cis-elements which are responding to JA and auxin signals, respectively. Deletion of NtWRKY-R1 promoter showed that JA and auxin signals were subdued by NtWRKY-R1, and the expression of NtWRKY-R1 was more sensitive to auxin than JA. Furthermore, Yeast two-hybrid experiment demonstrated that NtWRKY-R1 can interact with the actin-binding protein. Our data showed that the intensity of JA and auxin signals can be translated into the expression of NtWRKY-R1, which regulates the balance of actin polymerization and depolymerization through binding actin-binding protein, and then regulates the expression of genes related to nicotine synthesis. The results will help us better understand the function of the WRKY-IIe family in the signaling crosstalk of JA and auxin under damage stress.
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Eggenberger K, Sanyal P, Hundt S, Wadhwani P, Ulrich AS, Nick P. Challenge Integrity: The Cell-Penetrating Peptide BP100 Interferes with the Auxin-Actin Oscillator. PLANT & CELL PHYSIOLOGY 2017; 58:71-85. [PMID: 28173585 DOI: 10.1093/pcp/pcw161] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2016] [Accepted: 09/12/2016] [Indexed: 05/12/2023]
Abstract
Actin filaments are essential for the integrity of the cell membrane. In addition to this structural role, actin can modulate signaling by altering polar auxin flow. On the other hand, the organization of actin filaments is modulated by auxin constituting a self-referring signaling hub. Although the function of this auxin–actin oscillator is not clear, there is evidence for a functional link with stress signaling activated by the NADPH oxidase Respiratory burst oxidase Homolog (RboH). In the current work, we used the cell-penetrating peptide BP100 to induce a mild and transient perturbation of membrane integrity. We followed the response of actin to the BP100 uptake in a green fluorescent protein (GFP)-tagged actin marker line of tobacco Bright Yellow 2 (BY-2) cells by spinning disc confocal microscopy. We observed that BP100 enters in a stepwise manner and reduces the extent of actin remodeling. This actin ‘freezing’ can be rescued by the natural auxin IAA, and mimicked by the auxin-efflux inhibitor 1-napthylphthalamic acid (NPA). We further tested the role of the membrane-localized NADPH oxidase RboH using the specific inhibitor diphenyl iodonium (DPI), and found that DPI acts antagonistically to BP100, although DPI alone can induce a similar actin ‘freezing’ as well. We propose a working model, where the mild violation of membrane integrity by BP100 stimulates RboH, and the resulting elevated levels of reactive oxygen species interfere with actin dynamicity. The mitigating effect of auxin is explained by competition of auxin- and RboH-triggered signaling for superoxide anions. This self-referring auxin–actin–RboH hub might be essential for integrity sensing.
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Affiliation(s)
- Kai Eggenberger
- Botanical Institute and DFG-Center of Functional Nanostructures (CFN), Karlsruhe Institute of Technology (KIT), Kaiserstr, Karlsruhe, Germany
| | - Papia Sanyal
- Institute of Biological Interfaces (IBG-2) and DFG-Center of Functional Nanostructures (CFN), Institute of Organic Chemistry, Karlsruhe Institute of Technology (KIT), Fritz-Haber Weg 6, Karlsruhe, Germany
| | - Svenja Hundt
- Botanical Institute and DFG-Center of Functional Nanostructures (CFN), Karlsruhe Institute of Technology (KIT), Kaiserstr, Karlsruhe, Germany
| | - Parvesh Wadhwani
- Institute of Biological Interfaces (IBG-2) and DFG-Center of Functional Nanostructures (CFN), Institute of Organic Chemistry, Karlsruhe Institute of Technology (KIT), Fritz-Haber Weg 6, Karlsruhe, Germany
| | - Anne S Ulrich
- Institute of Biological Interfaces (IBG-2) and DFG-Center of Functional Nanostructures (CFN), Institute of Organic Chemistry, Karlsruhe Institute of Technology (KIT), Fritz-Haber Weg 6, Karlsruhe, Germany
| | - Peter Nick
- Botanical Institute and DFG-Center of Functional Nanostructures (CFN), Karlsruhe Institute of Technology (KIT), Kaiserstr, Karlsruhe, Germany
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Khatun K, Robin AHK, Park JI, Kim CK, Lim KB, Kim MB, Lee DJ, Nou IS, Chung MY. Genome-Wide Identification, Characterization and Expression Profiling of ADF Family Genes in Solanum lycopersicum L. Genes (Basel) 2016; 7:E79. [PMID: 27690110 PMCID: PMC5083918 DOI: 10.3390/genes7100079] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2016] [Revised: 09/12/2016] [Accepted: 09/22/2016] [Indexed: 12/15/2022] Open
Abstract
The actin depolymerizing factor (ADF) proteins have growth, development, defense-related and growth regulatory functions in plants. The present study used genome-wide analysis to investigate ADF family genes in tomato. Eleven tomato ADF genes were identified and differential expression patterns were found in different organs. SlADF6 was preferentially expressed in roots, suggesting its function in root development. SlADF1, SlADF3 and SlADF10 were predominately expressed in the flowers compared to the other organs and specifically in the stamen compared to other flower parts, indicating their potential roles in pollen development. The comparatively higher expression of SlADF3 and SlADF11 at early fruit developmental stages might implicate them in determining final fruit size. SlADF5 and SlADF8 had relatively higher levels of expression five days after the breaker stage of fruit development, suggesting their possible role in fruit ripening. Notably, six genes were induced by cold and heat, seven by drought, five by NaCl, and four each by abscisic acid (ABA), jasmonic acid (JA) and wounding treatments. The differential expression patterns of the SlADF genes under different types of stresses suggested their function in stress tolerance in tomato plants. Our results will be helpful for the functional characterization of ADF genes during organ and fruit development of tomato under different stresses.
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Affiliation(s)
- Khadiza Khatun
- Department of Agricultural Industry Economy and Education, Sunchon National University, 413 Jungangno, Suncheon, Jeonnam 540-950, Korea.
| | - Arif Hasan Khan Robin
- Department of Horticulture, Sunchon National University, 413 Jungangno, Suncheon, Jeonnam 540-950, Korea.
| | - Jong-In Park
- Department of Horticulture, Sunchon National University, 413 Jungangno, Suncheon, Jeonnam 540-950, Korea.
| | - Chang Kil Kim
- Department of Horticultural Science, Kyungpook National University, Daegu 702-701, Korea.
| | - Ki-Byung Lim
- Department of Horticultural Science, Kyungpook National University, Daegu 702-701, Korea.
| | - Min-Bae Kim
- Department of Agricultural Industry Economy and Education, Sunchon National University, 413 Jungangno, Suncheon, Jeonnam 540-950, Korea.
- Department of Agricultural Education, Sunchon National University, 413 Jungangno, Suncheon, Jeonnam 540-950, Korea.
| | - Do-Jin Lee
- Department of Agricultural Industry Economy and Education, Sunchon National University, 413 Jungangno, Suncheon, Jeonnam 540-950, Korea.
- Department of Agricultural Education, Sunchon National University, 413 Jungangno, Suncheon, Jeonnam 540-950, Korea.
| | - Ill Sup Nou
- Department of Horticulture, Sunchon National University, 413 Jungangno, Suncheon, Jeonnam 540-950, Korea.
| | - Mi-Young Chung
- Department of Agricultural Industry Economy and Education, Sunchon National University, 413 Jungangno, Suncheon, Jeonnam 540-950, Korea.
- Department of Agricultural Education, Sunchon National University, 413 Jungangno, Suncheon, Jeonnam 540-950, Korea.
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Gao N, Wadhwani P, Mühlhäuser P, Liu Q, Riemann M, Ulrich AS, Nick P. An antifungal protein from Ginkgo biloba binds actin and can trigger cell death. PROTOPLASMA 2016; 253:1159-74. [PMID: 26315821 DOI: 10.1007/s00709-015-0876-4] [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: 06/01/2015] [Accepted: 08/17/2015] [Indexed: 06/04/2023]
Abstract
Ginkbilobin is a short antifungal protein that had been purified and cloned from the seeds of the living fossil Ginkgo biloba. Homologues of this protein can be detected in all seed plants and the heterosporic fern Selaginella and are conserved with respect to domain structures, peptide motifs, and specific cysteine signatures. To get insight into the cellular functions of these conserved motifs, we expressed green fluorescent protein fusions of full-length and truncated ginkbilobin in tobacco BY-2 cells. We show that the signal peptide confers efficient secretion of ginkbilobin. When this signal peptide is either cleaved or masked, ginkbilobin binds and visualizes the actin cytoskeleton. This actin-binding activity of ginkbilobin is mediated by a specific subdomain just downstream of the signal peptide, and this subdomain can also coassemble with actin in vitro. Upon stable overexpression of this domain, we observe a specific delay in premitotic nuclear positioning indicative of a reduced dynamicity of actin. To elucidate the cellular response to the binding of this subdomain to actin, we use chemical engineering based on synthetic peptides comprising different parts of the actin-binding subdomain conjugated with the cell-penetrating peptide BP100 and with rhodamine B as a fluorescent reporter. Binding of this synthetic construct to actin efficiently induces programmed cell death. We discuss these findings in terms of a working model, where ginkbilobin can activate actin-dependent cell death.
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Affiliation(s)
- Ningning Gao
- Molecular Cell Biology, Botanical Institute and DFG-Center of Functional Nanostructures (CFN), Karlsruhe Institute of Technology (KIT), Kaiserstr. 2, 76128, Karlsruhe, Germany
| | - Parvesh Wadhwani
- Institute for Biological Interfaces (IBG-2), KIT, P.O. Box 3640, 76021, Karlsruhe, Germany
| | - Philipp Mühlhäuser
- Institute for Biological Interfaces (IBG-2), KIT, P.O. Box 3640, 76021, Karlsruhe, Germany
| | - Qiong Liu
- Molecular Cell Biology, Botanical Institute and DFG-Center of Functional Nanostructures (CFN), Karlsruhe Institute of Technology (KIT), Kaiserstr. 2, 76128, Karlsruhe, Germany
| | - Michael Riemann
- Molecular Cell Biology, Botanical Institute and DFG-Center of Functional Nanostructures (CFN), Karlsruhe Institute of Technology (KIT), Kaiserstr. 2, 76128, Karlsruhe, Germany
| | - Anne S Ulrich
- Institute for Biological Interfaces (IBG-2), KIT, P.O. Box 3640, 76021, Karlsruhe, Germany
- Institute of Organic Chemistry and CFN, KIT, Fritz-Haber-Weg 6, 76131, Karlsruhe, Germany
| | - Peter Nick
- Molecular Cell Biology, Botanical Institute and DFG-Center of Functional Nanostructures (CFN), Karlsruhe Institute of Technology (KIT), Kaiserstr. 2, 76128, Karlsruhe, Germany.
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Zhu J, Geisler M. Keeping it all together: auxin-actin crosstalk in plant development. JOURNAL OF EXPERIMENTAL BOTANY 2015; 66:4983-98. [PMID: 26085676 DOI: 10.1093/jxb/erv308] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Polar auxin transport and the action of the actin cytoskeleton are tightly interconnected, which is documented by the finding that auxin transporters reach their final destination by active movement of secretory vesicles along F-actin tracks. Moreover, auxin transporter polarity and flexibility is thought to depend on transporter cycling that requires endocytosis and exocytosis of vesicles. In this context, we have reviewed the current literature on an involvement of the actin cytoskeleton in polar auxin transport and identify known similarities and differences in its structure, function and dynamics in comparison to non-plant organisms. By describing how auxin modulates actin expression and actin organization and how actin and its stability affects auxin-transporter endocytosis and recycling, we discuss the current knowledge on regulatory auxin-actin feedback loops. We focus on known effects of auxin and of auxin transport inhibitors on the stability and organization of actin and examine the functionality of auxin and/or auxin transport inhibitor-binding proteins with respect to their suitability to integrate auxin/auxin transport inhibitor action. Finally, we indicate current difficulties in the interpretation of organ, time and concentration-dependent auxin/auxin transport inhibitor treatments and formulate simple future experimental guidelines.
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Affiliation(s)
- Jinsheng Zhu
- University of Fribourg, Department of Biology-Plant Biology, CH-1700 Fribourg, Switzerland
| | - Markus Geisler
- University of Fribourg, Department of Biology-Plant Biology, CH-1700 Fribourg, Switzerland
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Actin as deathly switch? How auxin can suppress cell-death related defence. PLoS One 2015; 10:e0125498. [PMID: 25933033 PMCID: PMC4416736 DOI: 10.1371/journal.pone.0125498] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2014] [Accepted: 03/17/2015] [Indexed: 11/19/2022] Open
Abstract
Plant innate immunity is composed of two layers--a basal immunity, and a specific effector-triggered immunity, which is often accompanied by hypersensitive cell death. Initiation of cell death depends on a complex network of signalling pathways. The phytohormone auxin as central regulator of plant growth and development represents an important component for the modulation of plant defence. In our previous work, we showed that cell death is heralded by detachment of actin from the membrane. Both, actin response and cell death, are triggered by the bacterial elicitor harpin in grapevine cells. In this study we investigated, whether harpin-triggered actin bundling is necessary for harpin-triggered cell death. Since actin organisation is dependent upon auxin, we used different auxins to suppress actin bundling. Extracellular alkalinisation and transcription of defence genes as the basal immunity were examined as well as cell death. Furthermore, organisation of actin was observed in response to pharmacological manipulation of reactive oxygen species and phospholipase D. We find that induction of defence genes is independent of auxin. However, auxin can suppress harpin-induced cell death and also counteract actin bundling. We integrate our findings into a model, where harpin interferes with an auxin dependent pathway that sustains dynamic cortical actin through the activity of phospholipase D. The antagonism between growth and defence is explained by mutual competition for signal molecules such as superoxide and phosphatidic acid. Perturbations of the auxin-actin pathway might be used to detect disturbed integrity of the plasma membrane and channel defence signalling towards programmed cell death.
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Guan X, Buchholz G, Nick P. Actin marker lines in grapevine reveal a gatekeeper function of guard cells. JOURNAL OF PLANT PHYSIOLOGY 2014; 171:1164-1173. [PMID: 24973589 DOI: 10.1016/j.jplph.2014.03.019] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2013] [Revised: 01/26/2014] [Accepted: 03/11/2014] [Indexed: 06/03/2023]
Abstract
Resistance to abiotic and biotic stress is a central topic for sustainable agriculture, especially in grapevine, one of the field crops with the highest economic output per acreage. As early cellular factors for plant defense, actin microfilaments (AF) are of high relevance. We therefore generated a transgenic actin marker line for grapevine by expressing a fusion protein between green fluorescent protein and the second actin-binding domain of Arabidopsis (Arabidopsis thaliana) fimbrin, AtFIM1. Based on this first cytoskeletal-marker line in grapevine, the response of AFs to phytopathogenic microorganisms could be followed in vivo. Upon inoculation with fluorescently labeled strains of phytopathogenic bacteria, actin responses were confined to the guard cells. In contrast, upon contact with zoospores of Plasmopara viticola, not only the guard cells, but also epidermal pavement cells, where no zoospores had attached responded with the formation of a perinuclear actin basket. Our data support the hypothesis that guard cells act as pacemakers of defense, dominating the responses of the remaining epidermal cells.
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Affiliation(s)
- Xin Guan
- Molecular Cell Biology, Botanical Institute, Karlsruhe Institute of Technology, Kaiserstraße 2, D-76128 Karlsruhe, Germany; College of Horticulture and Landscape Architecture, Southwest University, 400716 Chongqing, China.
| | - Günther Buchholz
- RLP AgroScience/AlPlanta - Institute for Plant Research, Breitenweg 71, D-67435 Neustadt an der Weinstraße, Germany
| | - Peter Nick
- Molecular Cell Biology, Botanical Institute, Karlsruhe Institute of Technology, Kaiserstraße 2, D-76128 Karlsruhe, Germany
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13
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Cheng X, Wu Y, Guo J, Du B, Chen R, Zhu L, He G. A rice lectin receptor-like kinase that is involved in innate immune responses also contributes to seed germination. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2013; 76:687-98. [PMID: 24033867 PMCID: PMC4285754 DOI: 10.1111/tpj.12328] [Citation(s) in RCA: 87] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/09/2013] [Revised: 08/14/2013] [Accepted: 09/05/2013] [Indexed: 05/20/2023]
Abstract
Seed germination and innate immunity both have significant effects on plant life spans because they control the plant's entry into the ecosystem and provide defenses against various external stresses, respectively. Much ecological evidence has shown that seeds with high vigor are generally more tolerant of various environmental stimuli in the field than those with low vigor. However, there is little genetic evidence linking germination and immunity in plants. Here, we show that the rice lectin receptor-like kinase OslecRK contributes to both seed germination and plant innate immunity. We demonstrate that knocking down the OslecRK gene depresses the expression of α-amylase genes, reducing seed viability and thereby decreasing the rate of seed germination. Moreover, it also inhibits the expression of defense genes, and so reduces the resistance of rice plants to fungal and bacterial pathogens as well as herbivorous insects. Yeast two-hybrid and co-immunoprecipitation experiments revealed that OslecRK interacts with an actin-depolymerizing factor (ADF) in vivo via its kinase domain. Moreover, the rice adf mutant exhibited a reduced seed germination rate due to the suppression of α-amylase gene expression. This mutant also exhibited depressed immune responses and reduced resistance to biotic stresses. Our results thus provide direct genetic evidence for a common physiological pathway connecting germination and immunity in plants. They also partially explain the common observation that high-vigor seeds often perform well in the field. The dual effects of OslecRK may be indicative of progressive adaptive evolution in rice.
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Affiliation(s)
- Xiaoyan Cheng
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan UniversityWuhan, 430072, China
| | - Yan Wu
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan UniversityWuhan, 430072, China
| | - Jianping Guo
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan UniversityWuhan, 430072, China
| | - Bo Du
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan UniversityWuhan, 430072, China
| | - Rongzhi Chen
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan UniversityWuhan, 430072, China
| | - Lili Zhu
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan UniversityWuhan, 430072, China
| | - Guangcun He
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan UniversityWuhan, 430072, China
- For correspondence (e-mail )
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Baluška F, Mancuso S. Root apex transition zone as oscillatory zone. FRONTIERS IN PLANT SCIENCE 2013; 4:354. [PMID: 24106493 PMCID: PMC3788588 DOI: 10.3389/fpls.2013.00354] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2013] [Accepted: 08/22/2013] [Indexed: 05/17/2023]
Abstract
Root apex of higher plants shows very high sensitivity to environmental stimuli. The root cap acts as the most prominent plant sensory organ; sensing diverse physical parameters such as gravity, light, humidity, oxygen, and critical inorganic nutrients. However, the motoric responses to these stimuli are accomplished in the elongation region. This spatial discrepancy was solved when we have discovered and characterized the transition zone which is interpolated between the apical meristem and the subapical elongation zone. Cells of this zone are very active in the cytoskeletal rearrangements, endocytosis and endocytic vesicle recycling, as well as in electric activities. Here we discuss the oscillatory nature of the transition zone which, together with several other features of this zone, suggest that it acts as some kind of command center. In accordance with the early proposal of Charles and Francis Darwin, cells of this root zone receive sensory information from the root cap and instruct the motoric responses of cells in the elongation zone.
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Affiliation(s)
- František Baluška
- Institute of Cellular and Molecular Botany, Department of Plant Cell Biology, University of BonnBonn, Germany
| | - Stefano Mancuso
- LINV – DiSPAA, Department of Agri-Food and Environmental Science, University of FlorenceSesto Fiorentino, Italy
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