1
|
Ruan H, Wang T, Ren H, Zhang Y. AtFH5-labeled secretory vesicles-dependent calcium oscillation drives exocytosis and stepwise bulge during pollen germination. Cell Rep 2023; 42:113319. [PMID: 37897722 DOI: 10.1016/j.celrep.2023.113319] [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: 05/06/2023] [Revised: 09/11/2023] [Accepted: 10/06/2023] [Indexed: 10/30/2023] Open
Abstract
Pollen germination is an essential step for delivering sperm cells to the embryo sac for double fertilization in flowering plants. The cytosolic Ca2+ concentration ([Ca2+]cyt) and vesicle dynamics are critical for pollen germination, but their potential correlation in pollen grains is not fully understood. Here, we report that [Ca2+]cyt oscillates periodically at the prospective germination sites during pollen germination. The [Ca2+]cyt is mainly from extracellular Ca2+ ([Ca2+]ext) influx, which implicates the Ca2+-permeable ion channel cyclic nucleotide-gated channel 18 (CNGC18). The [Ca2+]cyt oscillations spatiotemporally correlate with the accumulation of secretory vesicles labeled by a formin protein AtFH5, and disruption of vesicle accumulation inhibits the [Ca2+]cyt oscillations. In turn, the [Ca2+]cyt oscillations promote exocytosis, which leads to stepwise cell extension during pollen germination. Together, these data provide a timeline of vesicle dynamics, calcium oscillation, and exocytosis during pollen germination and highlight the importance of the correlation of these events for pollen germination.
Collapse
Affiliation(s)
- Huaqiang Ruan
- Key Laboratory of Cell Proliferation and Regulation Biology of Ministry of Education, College of Life Science, Beijing Normal University, Beijing 100875, China; Center for Biological Science and Technology, Zhuhai-Macao Biotechnology Joint Laboratory, Advanced Institute of Natural Science, Beijing Normal University, Zhuhai 519087, China
| | - Ting Wang
- Key Laboratory of Cell Proliferation and Regulation Biology of Ministry of Education, College of Life Science, Beijing Normal University, Beijing 100875, China
| | - Haiyun Ren
- Key Laboratory of Cell Proliferation and Regulation Biology of Ministry of Education, College of Life Science, Beijing Normal University, Beijing 100875, China; Center for Biological Science and Technology, Zhuhai-Macao Biotechnology Joint Laboratory, Advanced Institute of Natural Science, Beijing Normal University, Zhuhai 519087, China.
| | - Yi Zhang
- Key Laboratory of Cell Proliferation and Regulation Biology of Ministry of Education, College of Life Science, Beijing Normal University, Beijing 100875, China.
| |
Collapse
|
2
|
Zhou Z, Zheng S, Haq SIU, Zheng D, Qiu QS. Regulation of pollen tube growth by cellular pH and ions. JOURNAL OF PLANT PHYSIOLOGY 2022; 277:153792. [PMID: 35973258 DOI: 10.1016/j.jplph.2022.153792] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2022] [Revised: 07/29/2022] [Accepted: 08/06/2022] [Indexed: 06/15/2023]
Abstract
Tip growth of the pollen tube is a model system for the study of cell polarity establishment in flowering plants. The tip growth of the pollen tube displays an oscillating pattern corresponding to cellular ion and pH dynamics. Therefore, cellular pH and ions play an important role in pollen growth and development. In this review, we summarized the current advances in understanding the function of cellular pH and ions in regulating pollen tube growth. We analyzed the physiological roles and underlying mechanisms of cellular pH and ions, including Ca2+, K+, and Cl-, in regulating pollen tube growth. We further examined the function of Ca2+ in regulating cytoskeletons, small G proteins, and cell wall development in relation to pollen tube growth. We also examined the regulatory roles of cellular pH in pollen tube growth as well as pH regulation of ion flow, cell wall development, auxin signaling, and cytoskeleton function in pollen. In addition, we assessed the regulation of pollen tube growth by proton pumps and the maintenance of pH homeostasis in the trans-Golgi network by ion transporters. The interplay of ion homeostasis and pH dynamics was also assessed. We discussed the unanswered questions regarding pollen tube growth that need to be addressed in the future.
Collapse
Affiliation(s)
- Zhenguo Zhou
- MOE Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, Gansu, 73000, China.
| | - Sheng Zheng
- College of Life Sciences, Northwest Normal University, Lanzhou, Gansu, 730070, China; Academy of Plateau Science and Sustainability, Qinghai Normal University, Xining, Qinghai, 810016, China
| | - Syed Inzimam Ul Haq
- MOE Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, Gansu, 73000, China
| | - Dianfeng Zheng
- College of Coastal Agricultural Sciences, Guangdong Ocean University, Zhanjiang, Guangdong, 524088, China
| | - Quan-Sheng Qiu
- MOE Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, Gansu, 73000, China; Academy of Plateau Science and Sustainability, Qinghai Normal University, Xining, Qinghai, 810016, China; College of Coastal Agricultural Sciences, Guangdong Ocean University, Zhanjiang, Guangdong, 524088, China.
| |
Collapse
|
3
|
Expression of Clementine Asp-Rich Proteins (CcASP-RICH) in Tobacco Plants Interferes with the Mechanism of Pollen Tube Growth. Int J Mol Sci 2022; 23:ijms23147880. [PMID: 35887233 PMCID: PMC9316813 DOI: 10.3390/ijms23147880] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2022] [Revised: 07/13/2022] [Accepted: 07/15/2022] [Indexed: 11/29/2022] Open
Abstract
Low-molecular-weight, aspartic-acid-rich proteins (ASP-RICH) have been assumed to be involved in the self-incompatibility process of clementine. The role of ASP-RICH is not known, but hypothetically they could sequester calcium ions (Ca2+) and affect Ca2+-dependent mechanisms. In this article, we analyzed the effects induced by clementine ASP-RICH proteins (CcASP-RICH) when expressed in the tobacco heterologous system, focusing on the male gametophyte. The aim was to gain insight into the mechanism of action of ASP-RICH in a well-known cellular system, i.e., the pollen tube. Pollen tubes of tobacco transgenic lines expressing CcASP-RICH were analyzed for Ca2+ distribution, ROS, proton gradient, as well as cytoskeleton and cell wall. CcASP-RICH modulated Ca2+ content and consequently affected cytoskeleton organization and the deposition of cell wall components. In turn, this affected the growth pattern of pollen tubes. Although the expression of CcASP-RICH did not exert a remarkable effect on the growth rate of pollen tubes, effects at the level of growth pattern suggest that the expression of ASP-RICH may exert a regulatory action on the mechanism of plant cell growth.
Collapse
|
4
|
Wang J, Fu X, Zhang S, Chen G, Li S, Shangguan T, Zheng Y, Xu F, Chen ZH, Xu S. Evolutionary and Regulatory Pattern Analysis of Soybean Ca 2+ ATPases for Abiotic Stress Tolerance. FRONTIERS IN PLANT SCIENCE 2022; 13:898256. [PMID: 35665149 PMCID: PMC9161174 DOI: 10.3389/fpls.2022.898256] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/17/2022] [Accepted: 05/02/2022] [Indexed: 06/15/2023]
Abstract
P2-type Ca2+ ATPases are responsible for cellular Ca2+ transport, which plays an important role in plant development and tolerance to biotic and abiotic stresses. However, the role of P2-type Ca2+ ATPases in stress response and stomatal regulation is still elusive in soybean. In this study, a total of 12 P2-type Ca2+ ATPases genes (GmACAs and GmECAs) were identified from the genome of Glycine max. We analyzed the evolutionary relationship, conserved motif, functional domain, gene structure and location, and promoter elements of the family. Chlorophyll fluorescence imaging analysis showed that vegetable soybean leaves are damaged to different extents under salt, drought, cold, and shade stresses. Real-time quantitative PCR (RT-qPCR) analysis demonstrated that most of the GmACAs and GmECAs are up-regulated after drought, cold, and NaCl treatment, but are down-regulated after shading stress. Microscopic observation showed that different stresses caused significant stomatal closure. Spatial location and temporal expression analysis suggested that GmACA8, GmACA9, GmACA10, GmACA12, GmACA13, and GmACA11 might promote stomatal closure under drought, cold, and salt stress. GmECA1 might regulate stomatal closure in shading stress. GmACA1 and GmECA3 might have a negative function on cold stress. The results laid an important foundation for further study on the function of P2-type Ca2+ ATPase genes GmACAs and GmECAs for breeding abiotic stress-tolerant vegetable soybean.
Collapse
Affiliation(s)
- Jian Wang
- Central Laboratory, State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-products, Zhejiang Academy of Agricultural Sciences, Hangzhou, China
| | - Xujun Fu
- Central Laboratory, State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-products, Zhejiang Academy of Agricultural Sciences, Hangzhou, China
| | - Sheng Zhang
- Taizhou Seed Administration Station, Taizhou, China
| | - Guang Chen
- Central Laboratory, State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-products, Zhejiang Academy of Agricultural Sciences, Hangzhou, China
| | - Sujuan Li
- Central Laboratory, State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-products, Zhejiang Academy of Agricultural Sciences, Hangzhou, China
| | - Tengwei Shangguan
- College of Agriculture and Food Science, Zhejiang Agriculture and Forestry University, Hangzhou, China
| | - Yuanting Zheng
- Central Laboratory, State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-products, Zhejiang Academy of Agricultural Sciences, Hangzhou, China
| | - Fei Xu
- Central Laboratory, State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-products, Zhejiang Academy of Agricultural Sciences, Hangzhou, China
| | - Zhong-Hua Chen
- School of Science, Western Sydney University, Penrith, NSW, Australia
- Hawkesbury Institute for the Environment, Western Sydney University, Penrith, NSW, Australia
| | - Shengchun Xu
- Central Laboratory, State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-products, Zhejiang Academy of Agricultural Sciences, Hangzhou, China
| |
Collapse
|
5
|
Scheible N, Yoon GM, McCubbin AG. Calmodulin Domain Protein Kinase PiCDPK1 Regulates Pollen Tube Growth Polarity through Interaction with RhoGDI. PLANTS (BASEL, SWITZERLAND) 2022; 11:plants11030254. [PMID: 35161234 PMCID: PMC8838988 DOI: 10.3390/plants11030254] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/30/2021] [Revised: 01/14/2022] [Accepted: 01/17/2022] [Indexed: 05/14/2023]
Abstract
The pollen-specific calcium-dependent protein kinase PiCDPK1 of Petunia inflata has previously been shown to regulate polarity in tip growth in pollen tubes. Here we report the identification of a Rho Guanine Dissociation Inhibitor (PiRhoGDI1) as a PiCDPK1 interacting protein. We demonstrate that PiRhoGDI1 and PiCDPK1 interact in a yeast 2-hybrid assay, as well as in an in vitro pull-down assay, and that PiRhoGDI1 is phosphorylated by PiCDPK1 in vitro. We further demonstrate the PiRhoGDI1 is capable of rescuing the loss of growth polarity phenotype caused by over-expressing PiCDPK1 in vivo using stable transgenic plants. We confirmed that PiRhoGDI1 interacts with a pollen-expressed ROP GTPase isoform consistent with the established role of RhoGDIs in negatively regulating GTPases through their membrane removal and locking them in an inactive cytosolic complex. ROP is a central regulator of polarity in tip growth, upstream of Ca2+, and PiCDPK1 over-expression has been previously reported to lead to dramatic elevation of cytosolic Ca2+ through a positive feedback loop. The discovery that PiCDPK1 impacts ROP regulation via PiRhoGDI1 suggests that PiCDPK1 acts as RhoGDI displacement factor and leads us to propose a model which we hypothesize regulates the rapid recycling of ROP GTPase at the pollen tube tip.
Collapse
|
6
|
P2K1 Receptor, Heterotrimeric Gα Protein and CNGC2/4 Are Involved in Extracellular ATP-Promoted Ion Influx in the Pollen of Arabidopsis thaliana. PLANTS 2021; 10:plants10081743. [PMID: 34451790 PMCID: PMC8400636 DOI: 10.3390/plants10081743] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Revised: 08/20/2021] [Accepted: 08/20/2021] [Indexed: 11/17/2022]
Abstract
As an apoplastic signal, extracellular ATP (eATP) is involved in plant growth and development. eATP promotes tobacco pollen germination (PG) and pollen tube growth (PTG) by stimulating Ca2+ or K+ absorption. Nevertheless, the mechanisms underlying eATP-stimulated ion uptake and their role in PG and PTG are still unclear. Here, ATP addition was found to modulate PG and PTG in 34 plant species and showed a promoting effect in most of these species. Furthermore, by using Arabidopsis thaliana as a model, the role of several signaling components involved in eATP-promoted ion (Ca2+, K+) uptake, PG, and PTG were investigated. ATP stimulated while apyrase inhibited PG and PTG. Patch-clamping results showed that ATP promoted K+ and Ca2+ influx into pollen protoplasts. In loss-of-function mutants of P2K1 (dorn1-1 and dorn1-3), heterotrimeric G protein α subunit (gpa1-1, gpa1-2), or cyclic nucleotide gated ion channel (cngc2, cngc4), eATP-stimulated PG, PTG, and ion influx were all impaired. Our results suggest that these signaling components may be involved in eATP-promoted PG and PTG by regulating Ca2+ or K+ influx in Arabidopsis pollen grains.
Collapse
|
7
|
Yang H, You C, Yang S, Zhang Y, Yang F, Li X, Chen N, Luo Y, Hu X. The Role of Calcium/Calcium-Dependent Protein Kinases Signal Pathway in Pollen Tube Growth. FRONTIERS IN PLANT SCIENCE 2021; 12:633293. [PMID: 33767718 PMCID: PMC7985351 DOI: 10.3389/fpls.2021.633293] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Accepted: 02/15/2021] [Indexed: 05/21/2023]
Abstract
Pollen tube (PT) growth as a key step for successful fertilization is essential for angiosperm survival and especially vital for grain yield in cereals. The process of PT growth is regulated by many complex and delicate signaling pathways. Among them, the calcium/calcium-dependent protein kinases (Ca2+/CPKs) signal pathway has become one research focus, as Ca2+ ion is a well-known essential signal molecule for PT growth, which can be instantly sensed and transduced by CPKs to control myriad biological processes. In this review, we summarize the recent progress in understanding the Ca2+/CPKs signal pathway governing PT growth. We also discuss how this pathway regulates PT growth and how reactive oxygen species (ROS) and cyclic nucleotide are integrated by Ca2+ signaling networks.
Collapse
Affiliation(s)
- Hao Yang
- State Key Laboratory of Wheat & Maize Crop Science, Henan Agricultural University, Zhengzhou, China
| | - Chen You
- College of Life Science, Henan Normal University, Xinxiang, China
| | - Shaoyu Yang
- State Key Laboratory of Wheat & Maize Crop Science, Henan Agricultural University, Zhengzhou, China
| | - Yuping Zhang
- State Key Laboratory of Wheat & Maize Crop Science, Henan Agricultural University, Zhengzhou, China
| | - Fan Yang
- Department of Biology, Taiyuan Normal University, Jinzhong, China
| | - Xue Li
- State Key Laboratory of Wheat & Maize Crop Science, Henan Agricultural University, Zhengzhou, China
| | - Ning Chen
- State Key Laboratory of Wheat & Maize Crop Science, Henan Agricultural University, Zhengzhou, China
| | - Yanmin Luo
- State Key Laboratory of Wheat & Maize Crop Science, Henan Agricultural University, Zhengzhou, China
| | - Xiuli Hu
- State Key Laboratory of Wheat & Maize Crop Science, Henan Agricultural University, Zhengzhou, China
| |
Collapse
|
8
|
Scholz P, Anstatt J, Krawczyk HE, Ischebeck T. Signalling Pinpointed to the Tip: The Complex Regulatory Network That Allows Pollen Tube Growth. PLANTS (BASEL, SWITZERLAND) 2020; 9:E1098. [PMID: 32859043 PMCID: PMC7569787 DOI: 10.3390/plants9091098] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Revised: 08/18/2020] [Accepted: 08/23/2020] [Indexed: 12/13/2022]
Abstract
Plants display a complex life cycle, alternating between haploid and diploid generations. During fertilisation, the haploid sperm cells are delivered to the female gametophyte by pollen tubes, specialised structures elongating by tip growth, which is based on an equilibrium between cell wall-reinforcing processes and turgor-driven expansion. One important factor of this equilibrium is the rate of pectin secretion mediated and regulated by factors including the exocyst complex and small G proteins. Critically important are also non-proteinaceous molecules comprising protons, calcium ions, reactive oxygen species (ROS), and signalling lipids. Among the latter, phosphatidylinositol 4,5-bisphosphate and the kinases involved in its formation have been assigned important functions. The negatively charged headgroup of this lipid serves as an interaction point at the apical plasma membrane for partners such as the exocyst complex, thereby polarising the cell and its secretion processes. Another important signalling lipid is phosphatidic acid (PA), that can either be formed by the combination of phospholipases C and diacylglycerol kinases or by phospholipases D. It further fine-tunes pollen tube growth, for example by regulating ROS formation. How the individual signalling cues are intertwined or how external guidance cues are integrated to facilitate directional growth remain open questions.
Collapse
Affiliation(s)
- Patricia Scholz
- Department of Plant Biochemistry, Albrecht-von-Haller-Institute for Plant Sciences and Goettingen Center for Molecular Biosciences (GZMB), University of Goettingen, Justus-von-Liebig Weg 11, D-37077 Goettingen, Germany; (J.A.); (H.E.K.)
| | | | | | - Till Ischebeck
- Department of Plant Biochemistry, Albrecht-von-Haller-Institute for Plant Sciences and Goettingen Center for Molecular Biosciences (GZMB), University of Goettingen, Justus-von-Liebig Weg 11, D-37077 Goettingen, Germany; (J.A.); (H.E.K.)
| |
Collapse
|
9
|
Yang F, Wang T, Liu L. Pollen germination is impaired by disruption of a Shaker K + channel OsAKT1.2 in rice. JOURNAL OF PLANT PHYSIOLOGY 2020; 248:153140. [PMID: 32114250 DOI: 10.1016/j.jplph.2020.153140] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2020] [Revised: 02/10/2020] [Accepted: 02/11/2020] [Indexed: 06/10/2023]
Abstract
Potassium homeostasis is essential for pollen development and pollen-pistil interactions during the sexual reproduction of flowering plants. Here, we described the role of a Shaker K+ channel, OsAKT1.2, in rice pollen germination and growth. OsAKT1.2 is specifically expressed in the tricellular pollen, mature pollen grains and growing pollen tubes. Using CRISPR gene editing, we found that knockout lines did not differ from wildtype in vegetative growth, but showed decreased pollen germination rate both in the germination medium and in vivo. OsAKT1.2-GFP fusion protein was localized in the plasma membrane and enriched at the pollen tube tip. OsAKT1.2 could complement the yeast strain which is deficient in K+ intake. These findings suggest that OsAKT1.2 is associated with pollen germination and tube elongation in rice.
Collapse
Affiliation(s)
- Fan Yang
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China; College of Life Science, University of Chinese Academy of Sciences, Beijing 100093, China.
| | - Tai Wang
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China; College of Life Science, University of Chinese Academy of Sciences, Beijing 100093, China; Innovative Academy of Seed Design, Chinese Academy of Sciences, Beijing 100093, China.
| | - Lingtong Liu
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China.
| |
Collapse
|
10
|
Scheible N, McCubbin A. Signaling in Pollen Tube Growth: Beyond the Tip of the Polarity Iceberg. PLANTS (BASEL, SWITZERLAND) 2019; 8:E156. [PMID: 31181594 PMCID: PMC6630365 DOI: 10.3390/plants8060156] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Revised: 06/04/2019] [Accepted: 06/06/2019] [Indexed: 12/15/2022]
Abstract
The coordinated growth of pollen tubes through floral tissues to deliver the sperm cells to the egg and facilitate fertilization is a highly regulated process critical to the Angiosperm life cycle. Studies suggest that the concerted action of a variety of signaling pathways underlies the rapid polarized tip growth exhibited by pollen tubes. Ca2+ and small GTPase-mediated pathways have emerged as major players in the regulation of pollen tube growth. Evidence suggests that these two signaling pathways not only integrate with one another but also with a variety of other important signaling events. As we continue to elucidate the mechanisms involved in pollen tube growth, there is a growing importance in taking a holistic approach to studying these pathways in order to truly understand how tip growth in pollen tubes is orchestrated and maintained. This review considers our current state of knowledge of Ca2+-mediated and GTPase signaling pathways in pollen tubes, how they may intersect with one another, and other signaling pathways involved. There will be a particular focus on recent reports that have extended our understanding in these areas.
Collapse
Affiliation(s)
- Nolan Scheible
- School of Biological Sciences, Washington State University, Pullman, WA 99164-4236, USA.
| | - Andrew McCubbin
- School of Biological Sciences, Washington State University, Pullman, WA 99164-4236, USA.
- Center for Reproductive Biology, Pullman, WA, 99164, USA.
| |
Collapse
|
11
|
Wu Y, Qin B, Feng K, Yan R, Kang E, Liu T, Shang Z. Extracellular ATP promoted pollen germination and tube growth of Nicotiana tabacum through promoting K + and Ca 2+ absorption. PLANT REPRODUCTION 2018; 31:399-410. [PMID: 29934740 DOI: 10.1007/s00497-018-0341-6] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2017] [Accepted: 06/15/2018] [Indexed: 05/15/2023]
Abstract
Extracellular ATP (eATP) plays an essential role in plant growth, development, and stress tolerance. Here, we report that eATP participated in Nicotiana tabacum pollen germination (PG) and pollen tube growth (PTG) by regulating K+ and Ca2+ influx. Exogenous ATP or ADP effectively promoted PG and PTG in a dose-dependent manner; weakly hydrolysable ATP analog (ATPγS) showed a similar effect. AMP, adenosine, adenine, and phosphate did not affect PG or PTG. Within a certain range, higher concentrations of K+ or Ca2+ in the medium increased the effect of ATP in promoting PG and PTG. However, in mediums containing K+ or Ca2+ concentrations above this range, the effect of ATP was reversed, resulting in PG and PTG inhibition. Ca2+ chelators (EGTA), Ca2+ channel blockers, and K+ channel blockers suppressed ATP-promoted PG and PTG. Results from a patch clamp showed that ATP activated a K+ and Ca2+ influx in pollen protoplasts. These results suggest that, as an apoplastic signal, eATP may be involved in PG and PTG via regulating Ca2+ and K+ absorption.
Collapse
Affiliation(s)
- Yansheng Wu
- Hebei Key Laboratory of Molecular and Cellular Biology, Key Laboratory of Molecular and Cellular Biology of the Ministry of Education, College of Life Sciences, Hebei Normal University, Shijiazhuang, 050024, Hebei, China
- Department of Chemistry Engineering and Biological Technology, Xingtai University, Xingtai, 054001, Hebei, China
| | - Baozhi Qin
- Hebei Key Laboratory of Molecular and Cellular Biology, Key Laboratory of Molecular and Cellular Biology of the Ministry of Education, College of Life Sciences, Hebei Normal University, Shijiazhuang, 050024, Hebei, China
| | - Kaili Feng
- Hebei Key Laboratory of Molecular and Cellular Biology, Key Laboratory of Molecular and Cellular Biology of the Ministry of Education, College of Life Sciences, Hebei Normal University, Shijiazhuang, 050024, Hebei, China
| | - Ruolin Yan
- Hebei Key Laboratory of Molecular and Cellular Biology, Key Laboratory of Molecular and Cellular Biology of the Ministry of Education, College of Life Sciences, Hebei Normal University, Shijiazhuang, 050024, Hebei, China
| | - Erfang Kang
- Hebei Key Laboratory of Molecular and Cellular Biology, Key Laboratory of Molecular and Cellular Biology of the Ministry of Education, College of Life Sciences, Hebei Normal University, Shijiazhuang, 050024, Hebei, China
| | - Ting Liu
- Hebei Key Laboratory of Molecular and Cellular Biology, Key Laboratory of Molecular and Cellular Biology of the Ministry of Education, College of Life Sciences, Hebei Normal University, Shijiazhuang, 050024, Hebei, China
| | - Zhonglin Shang
- Hebei Key Laboratory of Molecular and Cellular Biology, Key Laboratory of Molecular and Cellular Biology of the Ministry of Education, College of Life Sciences, Hebei Normal University, Shijiazhuang, 050024, Hebei, China.
| |
Collapse
|
12
|
Lew RR. Nano-engineering pollination. THE NEW PHYTOLOGIST 2018; 220:8-9. [PMID: 30156021 DOI: 10.1111/nph.15358] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Affiliation(s)
- Roger R Lew
- Department of Biology, York University, 4700 Keele Street, Toronto, ON, M3J 1P3, Canada
| |
Collapse
|
13
|
Burri JT, Vogler H, Läubli NF, Hu C, Grossniklaus U, Nelson BJ. Feeling the force: how pollen tubes deal with obstacles. THE NEW PHYTOLOGIST 2018; 220:187-195. [PMID: 29905972 DOI: 10.1111/nph.15260] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/24/2018] [Accepted: 05/08/2018] [Indexed: 05/06/2023]
Abstract
Physical forces are involved in the regulation of plant development and morphogenesis by translating mechanical stress into the modification of physiological processes, which, in turn, can affect cellular growth. Pollen tubes respond rapidly to external stimuli and provide an ideal system to study the effect of mechanical cues at the single-cell level. Here, pollen tubes were exposed to mechanical stress while monitoring the reconfiguration of their growth and recording the generated forces in real-time. We combined a lab-on-a-chip device with a microelectromechanical systems (MEMS)-based capacitive force sensor to mimic and quantify the forces that are involved in pollen tube navigation upon confronting mechanical obstacles. Several stages of obstacle avoidance were identified, including force perception, growth adjustment and penetration. We have experimentally determined the perceptive force threshold, which is the force threshold at which the pollen tube reacts to an obstacle, for Lilium longiflorum and Arabidopsis thaliana. In addition, the method we developed provides a way to calculate turgor pressure based on force and optical data. Pollen tubes sense physical barriers and actively adjust their growth behavior to overcome them. Furthermore, our system offers an ideal platform to investigate intracellular activity during force perception and growth adaption in tip growing cells.
Collapse
Affiliation(s)
- Jan T Burri
- Multi-Scale Robotics Laboratory, Department of Mechanical and Process Engineering, ETH Zürich, Zürich, 8092, Switzerland
| | - Hannes Vogler
- Department of Plant and Microbial Biology and Zürich-Basel Plant Science Center, University of Zürich, Zürich, 8008, Switzerland
| | - Nino F Läubli
- Multi-Scale Robotics Laboratory, Department of Mechanical and Process Engineering, ETH Zürich, Zürich, 8092, Switzerland
| | - Chengzhi Hu
- Multi-Scale Robotics Laboratory, Department of Mechanical and Process Engineering, ETH Zürich, Zürich, 8092, Switzerland
| | - Ueli Grossniklaus
- Department of Plant and Microbial Biology and Zürich-Basel Plant Science Center, University of Zürich, Zürich, 8008, Switzerland
| | - Bradley J Nelson
- Multi-Scale Robotics Laboratory, Department of Mechanical and Process Engineering, ETH Zürich, Zürich, 8092, Switzerland
| |
Collapse
|
14
|
Hemelryck MV, Bernal R, Ispolatov Y, Dumais J. Lily Pollen Tubes Pulse According to a Simple Spatial Oscillator. Sci Rep 2018; 8:12135. [PMID: 30108317 PMCID: PMC6092427 DOI: 10.1038/s41598-018-30635-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2018] [Accepted: 06/07/2018] [Indexed: 11/23/2022] Open
Abstract
Polar growth is a fundamental mode of cell morphogenesis observed in nearly all major groups of organisms. Among polarly growing cells, the angiosperm pollen tubes have emerged as powerful experimental systems in large part because of their oscillatory growth, which provides a window into the network of interactions regulating morphogenesis. Empirical studies of oscillatory pollen tubes have sought to uncover the temporal sequence of cellular and molecular events that constitutes an oscillatory cycle. Here we show that in lily pollen tubes the distance or wavelength (λ = 6.3 ± 1.7 μm) over which an oscillatory cycle unfolds is more robust than the period of oscillation (τ = 39.1 ± 17.6 s) (n = 159 cells). Moreover, the oscillatory cycle is divided into slow and fast phases, with each phase unfolding over precisely one half of the wavelength. Using these observations, we show that a simple spatial bi-oscillator predicts the most common modes of oscillation observed in pollen tubes. These results call into question the traditional view of pollen tube morphogenesis as a temporal succession of cellular events. Space, not time, may be the most natural metric to inteprete the morphogenetic dynamics of these cells.
Collapse
Affiliation(s)
| | - Roberto Bernal
- Departamento de Física, Universidad de Santiago de Chile, Santiago, 9170124, Chile
| | - Yaroslav Ispolatov
- Departamento de Física, Universidad de Santiago de Chile, Santiago, 9170124, Chile
| | - Jacques Dumais
- Facultad de Ingeniería y Ciencias, Universidad Adolfo Ibáñez, Viña del Mar, Region V, Chile.
| |
Collapse
|
15
|
Barberini ML, Sigaut L, Huang W, Mangano S, Juarez SPD, Marzol E, Estevez J, Obertello M, Pietrasanta L, Tang W, Muschietti J. Calcium dynamics in tomato pollen tubes using the Yellow Cameleon 3.6 sensor. PLANT REPRODUCTION 2018; 31:159-169. [PMID: 29236154 DOI: 10.1007/s00497-017-0317-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2016] [Accepted: 12/04/2017] [Indexed: 06/07/2023]
Abstract
In vitro tomato pollen tubes show a cytoplasmic calcium gradient that oscillates with the same period as growth. Pollen tube growth requires coordination between the tip-focused cytoplasmic calcium concentration ([Ca2+]cyt) gradient and the actin cytoskeleton. This [Ca2+]cyt gradient is necessary for exocytosis of small vesicles, which contributes to the delivery of new membrane and cell wall at the pollen tube tip. The mechanisms that generate and maintain this [Ca2+]cyt gradient are not completely understood. Here, we studied calcium dynamics in tomato (Solanum lycopersicum) pollen tubes using transgenic tomato plants expressing the Yellow Cameleon 3.6 gene under the pollen-specific promoter LAT52. We use tomato as an experimental model because tomato is a Solanaceous plant that is easy to transform, and has an excellent genomic database and genetic stock center, and unlike Arabidopsis, tomato pollen is a good system to do biochemistry. We found that tomato pollen tubes showed an oscillating tip-focused [Ca2+]cyt gradient with the same period as growth. Then, we used a pharmacological approach to disturb the intracellular Ca2+ homeostasis, evaluating how the [Ca2+]cyt gradient, pollen germination and in vitro pollen tube growth were affected. We found that cyclopiazonic acid (CPA), a drug that inhibits plant PIIA-type Ca2+-ATPases, increased [Ca2+]cyt in the subapical zone, leading to the disappearance of the Ca2+ oscillations and inhibition of pollen tube growth. In contrast, 2-aminoethoxydiphenyl borate (2-APB), an inhibitor of Ca2+ released from the endoplasmic reticulum to the cytoplasm in animals cells, completely reduced [Ca2+]cyt at the tip of the tube, blocked the gradient and arrested pollen tube growth. Although both drugs have antagonistic effects on [Ca2+]cyt, both inhibited pollen tube growth triggering the disappearance of the [Ca2+]cyt gradient. When CPA and 2-APB were combined, their individual inhibitory effects on pollen tube growth were partially compensated. Finally, we found that GsMTx-4, a peptide from spider venom that blocks stretch-activated Ca2+ channels, inhibited tomato pollen germination and had a heterogeneous effect on pollen tube growth, suggesting that these channels are also involved in the maintenance of the [Ca2+]cyt gradient. All these results indicate that tomato pollen tube is an excellent model to study calcium dynamics.
Collapse
Affiliation(s)
- María Laura Barberini
- Instituto de Investigaciones en Ingeniería Genética y Biología Molecular, "Dr. Héctor Torres" (INGEBI-CONICET), Vuelta de Obligado 2490, C1428ADN, Buenos Aires, Argentina
| | - Lorena Sigaut
- Instituto de Física de Buenos Aires (IFIBA-CONICET), Departamento de Física, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Intendente Güiraldes 2160, Ciudad Universitaria, Pabellón I, C1428EHA, Buenos Aires, Argentina
| | - Weijie Huang
- National Key Laboratory of Plant Molecular Genetics, Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 300 Fenglin Road, Shanghai, 200032, China
- Department of Cell and Developmental Biology, John Innes Centre, Norwich Research Park, Norwich, NR4 7UH, United Kingdom
| | - Silvina Mangano
- Fundación Instituto Leloir and Instituto de Investigaciones Bioquímicas de Buenos Aires (IIBBA-CONICET), Av. Patricias Argentinas 435, CP C1405BWE, Buenos Aires, Argentina
| | - Silvina Paola Denita Juarez
- Fundación Instituto Leloir and Instituto de Investigaciones Bioquímicas de Buenos Aires (IIBBA-CONICET), Av. Patricias Argentinas 435, CP C1405BWE, Buenos Aires, Argentina
| | - Eliana Marzol
- Fundación Instituto Leloir and Instituto de Investigaciones Bioquímicas de Buenos Aires (IIBBA-CONICET), Av. Patricias Argentinas 435, CP C1405BWE, Buenos Aires, Argentina
| | - José Estevez
- Fundación Instituto Leloir and Instituto de Investigaciones Bioquímicas de Buenos Aires (IIBBA-CONICET), Av. Patricias Argentinas 435, CP C1405BWE, Buenos Aires, Argentina
| | - Mariana Obertello
- Instituto de Investigaciones en Ingeniería Genética y Biología Molecular, "Dr. Héctor Torres" (INGEBI-CONICET), Vuelta de Obligado 2490, C1428ADN, Buenos Aires, Argentina
| | - Lía Pietrasanta
- Instituto de Física de Buenos Aires (IFIBA-CONICET), Departamento de Física, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Intendente Güiraldes 2160, Ciudad Universitaria, Pabellón I, C1428EHA, Buenos Aires, Argentina
- Centro de Microscopías Avanzadas, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Intendente Güiraldes 2160, Ciudad Universitaria, Pabellón I, C1428EHA, Buenos Aires, Argentina
| | - Weihua Tang
- National Key Laboratory of Plant Molecular Genetics, Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 300 Fenglin Road, Shanghai, 200032, China
| | - Jorge Muschietti
- Instituto de Investigaciones en Ingeniería Genética y Biología Molecular, "Dr. Héctor Torres" (INGEBI-CONICET), Vuelta de Obligado 2490, C1428ADN, Buenos Aires, Argentina.
- Departamento de Biodiversidad y Biología Experimental, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Intendente Güiraldes 2160, Ciudad Universitaria, Pabellón II, C1428EGA, Buenos Aires, Argentina.
| |
Collapse
|
16
|
Gutermuth T, Herbell S, Lassig R, Brosché M, Romeis T, Feijó JA, Hedrich R, Konrad KR. Tip-localized Ca 2+ -permeable channels control pollen tube growth via kinase-dependent R- and S-type anion channel regulation. THE NEW PHYTOLOGIST 2018; 218:1089-1105. [PMID: 29522235 DOI: 10.1111/nph.15067] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2017] [Accepted: 01/18/2018] [Indexed: 05/26/2023]
Abstract
Pollen tubes (PTs) are characterized by having tip-focused cytosolic calcium ion (Ca2+ ) concentration ([Ca2+ ]cyt ) gradients, which are believed to control PT growth. However, the mechanisms by which the apical [Ca2+ ]cyt orchestrates PT growth are not well understood. Here, we aimed to identify these mechanisms by combining reverse genetics, cell biology, electrophysiology, and live-cell Ca2+ and anion imaging. We triggered Ca2+ -channel activation by applying hyperpolarizing voltage pulses and observed that the evoked [Ca2+ ]cyt increases were paralleled by high anion channel activity and a decrease in the cytosolic anion concentration at the PT tip. We confirmed a functional correlation between these patterns by showing that inhibition of Ca2+ -permeable channels eliminated the [Ca2+ ]cyt increase, resulting in the abrogation of anion channel activity via Ca2+ -dependent protein kinases (CPKs). Functional characterization of CPK and anion-channel mutants revealed a CPK2/20/6-dependent activation of SLAH3 and ALMT12/13/14 anion channels. The impaired growth phenotypes of anion channel and CPK mutants support the physiological significance of a kinase- and Ca2+ -dependent pathway to control PT growth via anion channel activation. Other than unveiling this functional link, our membrane hyperpolarization method allows for unprecedented manipulation of the [Ca2+ ]cyt gradient or oscillations in the PT tips and opens an array of opportunities for channel screenings.
Collapse
Affiliation(s)
- Timo Gutermuth
- Department of Botany I, Julius-Von-Sachs Institute for Biosciences, University of Wuerzburg, 97082, Wuerzburg, Germany
| | - Sarah Herbell
- Department of Botany I, Julius-Von-Sachs Institute for Biosciences, University of Wuerzburg, 97082, Wuerzburg, Germany
| | - Roman Lassig
- Plant Biochemistry, Dahlem Centre of Plant Sciences, FU Berlin, Königin-Luise-Straße 12/16, 14195, Berlin, Germany
| | - Mikael Brosché
- Organismal and Evolutionary Biology Research Programme, Faculty of Biological and Environmental Sciences, University of Helsinki, 00014, Helsinki, Finland
- Institute of Technology, University of Tartu, Nooruse 1, 50411, Tartu, Estonia
| | - Tina Romeis
- Plant Biochemistry, Dahlem Centre of Plant Sciences, FU Berlin, Königin-Luise-Straße 12/16, 14195, Berlin, Germany
| | - José Alberto Feijó
- Department of Cell Biology & Molecular Genetics, University of Maryland, 2136 Bioscience Research Building, College Park, MD, 20742-5815, USA
| | - Rainer Hedrich
- Department of Botany I, Julius-Von-Sachs Institute for Biosciences, University of Wuerzburg, 97082, Wuerzburg, Germany
| | - Kai Robert Konrad
- Department of Botany I, Julius-Von-Sachs Institute for Biosciences, University of Wuerzburg, 97082, Wuerzburg, Germany
| |
Collapse
|
17
|
Simultaneous imaging and functional studies reveal a tight correlation between calcium and actin networks. Proc Natl Acad Sci U S A 2018; 115:E2869-E2878. [PMID: 29507239 DOI: 10.1073/pnas.1711037115] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Tip-growing cells elongate in a highly polarized manner via focused secretion of flexible cell-wall material. Calcium has been implicated as a vital factor in regulating the deposition of cell-wall material. However, deciphering the molecular and mechanistic calcium targets in vivo has remained challenging. Here, we investigated intracellular calcium dynamics in the moss Physcomitrella patens, which provides a system with an abundant source of genetically identical tip-growing cells, excellent cytology, and a large molecular genetic tool kit. To visualize calcium we used a genetically encoded cytosolic FRET probe, revealing a fluctuating tipward gradient with a complex oscillatory profile. Wavelet analysis coupled with a signal-sifting algorithm enabled the quantitative comparison of the calcium behavior in cells where growth was inhibited mechanically, pharmacologically, or genetically. We found that cells with suppressed growth have calcium oscillatory profiles with longer frequencies, suggesting that there is a feedback between the calcium gradient and growth. To investigate the mechanistic basis for this feedback we simultaneously imaged cytosolic calcium and actin, which has been shown to be essential for tip growth. We found that high cytosolic calcium promotes disassembly of a tip-focused actin spot, while low calcium promotes assembly. In support of this, abolishing the calcium gradient resulted in dramatic actin accumulation at the tip. Together these data demonstrate that tipward calcium is quantitatively linked to actin accumulation in vivo and that the moss P. patens provides a powerful system to uncover mechanistic links between calcium, actin, and growth.
Collapse
|
18
|
Lamport DTA, Tan L, Held MA, Kieliszewski MJ. Pollen tube growth and guidance: Occam's razor sharpened on a molecular arabinogalactan glycoprotein Rosetta Stone. THE NEW PHYTOLOGIST 2018; 217:491-500. [PMID: 28990197 DOI: 10.1111/nph.14845] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Occam's Razor suggests a new model of pollen tube tip growth based on a novel Hechtian oscillator that integrates a periplasmic arabinogalactan glycoprotein-calcium (AGP-Ca2+ ) capacitor with tip-localized AGPs as the source of tip-focussed cytosolic Ca2+ oscillations: Hechtian adhesion between the plasma membrane and the cell wall of the growing tip acts as a piconewton force transducer that couples the internal stress of a rapidly growing wall to the plasma membrane. Such Hechtian transduction opens stretch-activated Ca2+ channels and activates H+ -ATPase proton pump efflux that dissociates periplasmic AGP-Ca2+ resulting in a Ca2+ influx that activates exocytosis of wall precursors. Thus, a highly simplified pectic primary cell wall regulates its own synthesis by a Hechtian growth oscillator that regulates overall tip growth. By analogy with the three cryptic inscriptions of the classical Rosetta Stone, the Hechtian Hypothesis translates classical AGP function as a Ca2+ capacitor, pollen tube guide and wall plasticizer into a simple but widely applicable model of tip growth. Even wider ramifications of the Hechtian oscillator may implicate AGPs in osmosensing or gravisensing and other tropisms, leading us yet further towards the Holy Grail of plant growth.
Collapse
Affiliation(s)
- Derek T A Lamport
- School of Life Sciences, University of Sussex, Falmer, Brighton, BN1 9QG, UK
| | - Li Tan
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA, 30602-4712, USA
| | - Michael A Held
- Department of Chemistry and Biochemistry, Ohio University, Athens, OH, 45701, USA
| | | |
Collapse
|
19
|
Bascom CS, Hepler PK, Bezanilla M. Interplay between Ions, the Cytoskeleton, and Cell Wall Properties during Tip Growth. PLANT PHYSIOLOGY 2018; 176:28-40. [PMID: 29138353 PMCID: PMC5761822 DOI: 10.1104/pp.17.01466] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2017] [Accepted: 11/05/2017] [Indexed: 05/08/2023]
Abstract
Tip growth is a focused and tightly regulated apical explosion that depends on the interconnected activities of ions, the cytoskeleton, and the cell wall.
Collapse
Affiliation(s)
- Carlisle S Bascom
- Department of Biological Sciences, Dartmouth College, Hanover, New Hampshire 03755
- Plant Biology Graduate Program, University of Massachusetts, Amherst, Massachusetts 01002
| | - Peter K Hepler
- Biology Department, University of Massachusetts, Amherst, Massachusetts 01002
| | - Magdalena Bezanilla
- Department of Biological Sciences, Dartmouth College, Hanover, New Hampshire 03755
| |
Collapse
|
20
|
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.
Collapse
|
21
|
Tran D, Galletti R, Neumann ED, Dubois A, Sharif-Naeini R, Geitmann A, Frachisse JM, Hamant O, Ingram GC. A mechanosensitive Ca 2+ channel activity is dependent on the developmental regulator DEK1. Nat Commun 2017; 8:1009. [PMID: 29044106 PMCID: PMC5647327 DOI: 10.1038/s41467-017-00878-w] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2015] [Accepted: 08/02/2017] [Indexed: 01/08/2023] Open
Abstract
Responses of cells to mechanical stress are thought to be critical in coordinating growth and development. Consistent with this idea, mechanically activated channels play important roles in animal development. For example, the PIEZO1 channel controls cell division and epithelial-layer integrity and is necessary for vascular development in mammals. In plants, the actual contribution of mechanoperception to development remains questionable because very few putative mechanosensors have been identified and the phenotypes of the corresponding mutants are rather mild. Here, we show that the Arabidopsis Defective Kernel 1 (DEK1) protein, which is essential for development beyond early embryogenesis, is associated with a mechanically activated Ca2+ current in planta, suggesting that perception of mechanical stress plays a critical role in plant development.
Collapse
Affiliation(s)
- Daniel Tran
- Laboratoire Reproduction et Développement des Plantes, Université de Lyon, ENS de Lyon, UCB Lyon 1, CNRS, INRA, F-69342, Lyon, France
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Sud, Sciences Plant Saclay, Avenue de la Terrasse, 91198, Gif sur Yvette Cedex, France
- Department of Physiology and Cell Information Systems, McGill University, Montreal, Québec, Canada, H3G-0B1
| | - Roberta Galletti
- Laboratoire Reproduction et Développement des Plantes, Université de Lyon, ENS de Lyon, UCB Lyon 1, CNRS, INRA, F-69342, Lyon, France
| | - Enrique D Neumann
- Laboratoire Reproduction et Développement des Plantes, Université de Lyon, ENS de Lyon, UCB Lyon 1, CNRS, INRA, F-69342, Lyon, France
| | - Annick Dubois
- Laboratoire Reproduction et Développement des Plantes, Université de Lyon, ENS de Lyon, UCB Lyon 1, CNRS, INRA, F-69342, Lyon, France
| | - Reza Sharif-Naeini
- Department of Physiology and Cell Information Systems, McGill University, Montreal, Québec, Canada, H3G-0B1
| | - Anja Geitmann
- Department of Plant Science, McGill University, Ste-Anne-de-Bellevue, Montreal, Québec, Canada, H9X3V9
| | - Jean-Marie Frachisse
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Sud, Sciences Plant Saclay, Avenue de la Terrasse, 91198, Gif sur Yvette Cedex, France
| | - Olivier Hamant
- Laboratoire Reproduction et Développement des Plantes, Université de Lyon, ENS de Lyon, UCB Lyon 1, CNRS, INRA, F-69342, Lyon, France.
| | - Gwyneth C Ingram
- Laboratoire Reproduction et Développement des Plantes, Université de Lyon, ENS de Lyon, UCB Lyon 1, CNRS, INRA, F-69342, Lyon, France.
| |
Collapse
|
22
|
Hamilton ES, Haswell ES. The Tension-sensitive Ion Transport Activity of MSL8 is Critical for its Function in Pollen Hydration and Germination. PLANT & CELL PHYSIOLOGY 2017; 58:1222-1237. [PMID: 28339550 DOI: 10.1093/pcp/pcw230] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2016] [Accepted: 12/07/2016] [Indexed: 05/02/2023]
Abstract
All cells respond to osmotic challenges, including those imposed during normal growth and development. Mechanosensitive (MS) ion channels provide a conserved mechanism for regulating osmotic forces by conducting ions in response to increased membrane tension. We previously demonstrated that the MS ion channel MscS-Like 8 (MSL8) is required for pollen to survive multiple osmotic challenges that occur during the normal process of fertilization, and that it can inhibit pollen germination. However, it remained unclear whether these physiological functions required ion flux through a mechanically gated channel provided by MSL8. We introduced two point mutations into the predicted pore-lining domain of MSL8 that disrupted normal channel function in different ways. The Ile711Ser mutation increased the tension threshold of the MSL8 channel while leaving conductance unchanged, and the Phe720Leu mutation severely disrupted the MSL8 channel. Both of these mutations impaired the ability of MSL8 to preserve pollen viability during hydration and to maintain the integrity of the pollen tube when expressed at endogenous levels. When overexpressed in an msl8-4 null background, MSL8I711S could partially rescue loss-of-function phenotypes, while MSL8F720L could not. When overexpressed in the wild-type Ler background, MSL8I711S suppressed pollen germination, similar to wild-type MSL8. In contrast, MSL8F720L failed to suppress pollen germination and increased pollen bursting, thereby phenocopying the msl8-4 mutant. Thus, an intact MSL8 channel is required for normal pollen function during hydration and germination. These data establish MSL8 as the first plant MS channel to fulfill previously established criteria for assignment as a mechanotransducer.
Collapse
Affiliation(s)
- Eric S Hamilton
- Department of Biology, Box 1137, Washington University in St. Louis, One Brookings Drive, Saint Louis, MO 63130, USA
| | - Elizabeth S Haswell
- Department of Biology, Box 1137, Washington University in St. Louis, One Brookings Drive, Saint Louis, MO 63130, USA
| |
Collapse
|
23
|
Winship LJ, Rounds C, Hepler PK. Perturbation Analysis of Calcium, Alkalinity and Secretion during Growth of Lily Pollen Tubes. PLANTS 2016; 6:plants6010003. [PMID: 28042810 PMCID: PMC5371762 DOI: 10.3390/plants6010003] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/31/2016] [Revised: 12/24/2016] [Accepted: 12/26/2016] [Indexed: 01/07/2023]
Abstract
Pollen tubes grow by spatially and temporally regulated expansion of new material secreted into the cell wall at the tip of the tube. A complex web of interactions among cellular components, ions and small molecule provides dynamic control of localized expansion and secretion. Cross-correlation studies on oscillating lily (Lilium formosanum Wallace) pollen tubes showed that an increase in intracellular calcium follows an increase in growth, whereas the increase in the alkaline band and in secretion both anticipate the increase in growth rate. Calcium, as a follower, is unlikely to be a stimulator of growth, whereas the alkaline band, as a leader, may be an activator. To gain further insight herein we reversibly inhibited growth with potassium cyanide (KCN) and followed the re-establishment of calcium, pH and secretion patterns as growth resumed. While KCN markedly slows growth and causes the associated gradients of calcium and pH to sharply decline, its removal allows growth and vital processes to fully recover. The calcium gradient reappears before growth restarts; however, it is preceded by both the alkaline band and secretion, in which the alkaline band is slightly advanced over secretion. Thus the pH gradient, rather than the tip-focused calcium gradient, may regulate pollen tube growth.
Collapse
Affiliation(s)
| | - Caleb Rounds
- Biology Department, University of Massachusetts, Amherst, MA 01003, USA.
| | - Peter K Hepler
- Biology Department, University of Massachusetts, Amherst, MA 01003, USA.
| |
Collapse
|
24
|
Pérez Di Giorgio JA, Soto GC, Muschietti JP, Amodeo G. Pollen Aquaporins: The Solute Factor. FRONTIERS IN PLANT SCIENCE 2016; 7:1659. [PMID: 27881985 PMCID: PMC5101680 DOI: 10.3389/fpls.2016.01659] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2016] [Accepted: 10/21/2016] [Indexed: 05/12/2023]
Abstract
In the recent years, the biophysical properties and presumed physiological role of aquaporins (AQPs) have been expanded to specialized cells where water and solute exchange are crucial traits. Complex but unique processes such as stomatal movement or pollen hydration and germination have been addressed not only by identifying the specific AQP involved but also by studying how these proteins integrate and coordinate cellular activities and functions. In this review, we referred specifically to pollen-specific AQPs and analyzed what has been assumed in terms of transport properties and what has been found in terms of their physiological role. Unlike that in many other cells, the AQP machinery in mature pollen lacks plasma membrane intrinsic proteins, which are extensively studied for their high water capacity exchange. Instead, a variety of TIPs and NIPs are expressed in pollen. These findings have altered the initial understanding of AQPs and water exchange to consider specific and diverse solutes that might be critical to sustaining pollen's success. The spatial and temporal distribution of the pollen AQPs also reflects a regulatory mechanism that allowing a properly adjusting water and solute exchange.
Collapse
Affiliation(s)
- Juliana A. Pérez Di Giorgio
- Instituto de Investigaciones en Ingeniería Genética y Biología Molecular – Consejo Nacional de Investigaciones Científicas y TécnicasBuenos Aires, Argentina
| | - Gabriela C. Soto
- Instituto de Genética Ewald A. Favret – Centro de Investigación en Ciencias Veterinarias y Agronómicas – Instituto Nacional de Tecnología Agropecuaria – Consejo Nacional de Investigaciones Científicas y TécnicasBuenos Aires, Argentina
| | - Jorge P. Muschietti
- Instituto de Investigaciones en Ingeniería Genética y Biología Molecular – Consejo Nacional de Investigaciones Científicas y TécnicasBuenos Aires, Argentina
- Departamento de Biodiversidad y Biología Experimental, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos AiresBuenos Aires, Argentina
| | - Gabriela Amodeo
- Departamento de Biodiversidad y Biología Experimental, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos AiresBuenos Aires, Argentina
- Instituto de Biodiversidad y Biología Experimental y Aplicada – Universidad de Buenos Aires–Consejo Nacional de Investigaciones Científicas y TécnicasBuenos Aires, Argentina
| |
Collapse
|
25
|
Hamilton ES, Jensen GS, Maksaev G, Katims A, Sherp AM, Haswell ES. Mechanosensitive channel MSL8 regulates osmotic forces during pollen hydration and germination. Science 2016; 350:438-41. [PMID: 26494758 DOI: 10.1126/science.aac6014] [Citation(s) in RCA: 139] [Impact Index Per Article: 17.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Pollen grains undergo dramatic changes in cellular water potential as they deliver the male germ line to female gametes, and it has been proposed that mechanosensitive ion channels may sense the resulting mechanical stress. Here, we identify and characterize MscS-like 8 (MSL8), a pollen-specific, membrane tension-gated ion channel required for pollen to survive the hypoosmotic shock of rehydration and for full male fertility. MSL8 negatively regulates pollen germination but is required for cellular integrity during germination and tube growth. MSL8 thus senses and responds to changes in membrane tension associated with pollen hydration and germination. These data further suggest that homologs of bacterial MscS have been repurposed in eukaryotes to function as mechanosensors in multiple developmental and environmental contexts.
Collapse
Affiliation(s)
- Eric S Hamilton
- Department of Biology, Washington University in Saint Louis, Saint Louis, MO 63130, USA
| | - Gregory S Jensen
- Department of Biology, Washington University in Saint Louis, Saint Louis, MO 63130, USA
| | - Grigory Maksaev
- Department of Biology, Washington University in Saint Louis, Saint Louis, MO 63130, USA
| | - Andrew Katims
- Department of Biology, Washington University in Saint Louis, Saint Louis, MO 63130, USA
| | - Ashley M Sherp
- Department of Biology, Washington University in Saint Louis, Saint Louis, MO 63130, USA
| | - Elizabeth S Haswell
- Department of Biology, Washington University in Saint Louis, Saint Louis, MO 63130, USA.
| |
Collapse
|
26
|
Cyclic nucleotide-gated channel 18 is an essential Ca2+ channel in pollen tube tips for pollen tube guidance to ovules in Arabidopsis. Proc Natl Acad Sci U S A 2016; 113:3096-101. [PMID: 26929345 DOI: 10.1073/pnas.1524629113] [Citation(s) in RCA: 116] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
In flowering plants, pollen tubes are guided into ovules by multiple attractants from female gametophytes to release paired sperm cells for double fertilization. It has been well-established that Ca(2+) gradients in the pollen tube tips are essential for pollen tube guidance and that plasma membrane Ca(2+) channels in pollen tube tips are core components that regulate Ca(2+) gradients by mediating and regulating external Ca(2+) influx. Therefore, Ca(2+) channels are the core components for pollen tube guidance. However, there is still no genetic evidence for the identification of the putative Ca(2+) channels essential for pollen tube guidance. Here, we report that the point mutations R491Q or R578K in cyclic nucleotide-gated channel 18 (CNGC18) resulted in abnormal Ca(2+) gradients and strong pollen tube guidance defects by impairing the activation of CNGC18 in Arabidopsis. The pollen tube guidance defects of cngc18-17 (R491Q) and of the transfer DNA (T-DNA) insertion mutant cngc18-1 (+/-) were completely rescued by CNGC18. Furthermore, domain-swapping experiments showed that CNGC18's transmembrane domains are indispensable for pollen tube guidance. Additionally, we found that, among eight Ca(2+) channels (including six CNGCs and two glutamate receptor-like channels), CNGC18 was the only one essential for pollen tube guidance. Thus, CNGC18 is the long-sought essential Ca(2+) channel for pollen tube guidance in Arabidopsis.
Collapse
|
27
|
Lu M, Zhang Y, Tang S, Pan J, Yu Y, Han J, Li Y, Du X, Nan Z, Sun Q. AtCNGC2 is involved in jasmonic acid-induced calcium mobilization. JOURNAL OF EXPERIMENTAL BOTANY 2016; 67:809-19. [PMID: 26608645 DOI: 10.1093/jxb/erv500] [Citation(s) in RCA: 58] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
Calcium (Ca(2+)) mobilization is a central theme in various plant signal transduction pathways. We demonstrate that Arabidopsis thaliana cyclic nucleotide-gated channel 2 (AtCNGC2) is involved in jasmonic acid (JA)-induced apoplastic Ca(2+) influx in Arabidopsis epidermal cells. Ca(2+) imaging results showed that JA can induce an elevation in the cytosolic cAMP concentration ([cAMP]cyt), reaching a maximum within 3 min. Dibutyryl cAMP (db-cAMP), a cell membrane-permeable analogue of cAMP, induced an increase in the cytosolic Ca(2+) concentration ([Ca(2+)]cyt), with a peak at 4 min. This [Ca(2+)]cyt increase was triggered by the JA-induced increase in [cAMP]cyt. W-7[N-(6-aminohexyl)-5-chloro-1-naphthalenesulfonamide], an antagonist of calmodulin, positively modulated the JA-induced increase in [Ca(2+)]cyt, while W-5[N-(6-aminohexyl)-1-naphthalenesulfonamide], an inactive antagonist of calmodulin, had no apparent effect. db-cAMP and JA positively induced the expression of primary (i.e. JAZ1 and MYC2) and secondary (i.e. VSP1) response genes in the JA signalling pathway in wild-type Arabidopsis thaliana, whereas they had no significant effect in the AtCNGC2 mutant 'defense, no death (dnd1) plants. These data provide evidence that JA first induces the elevation of cAMP, and cAMP, as an activating ligand, activates the AtCNGC2 channel, resulting in apoplastic Ca(2+) influx through AtCNGC2.
Collapse
Affiliation(s)
- Min Lu
- Plant Science and Technology College, Beijing University of Agriculture, Beijing 102206, China
| | - Yanyan Zhang
- Plant Science and Technology College, Beijing University of Agriculture, Beijing 102206, China
| | - Shikun Tang
- Plant Science and Technology College, Beijing University of Agriculture, Beijing 102206, China
| | - Jinbao Pan
- Plant Science and Technology College, Beijing University of Agriculture, Beijing 102206, China
| | - Yongkun Yu
- College of Biological Science and Engineering, Beijing University of Agriculture, Beijing 102206, China
| | - Jun Han
- Plant Science and Technology College, Beijing University of Agriculture, Beijing 102206, China
| | - Yangyang Li
- Plant Science and Technology College, Beijing University of Agriculture, Beijing 102206, China School of Life Sciences, Shandong Normal University, Jinan 250014, China
| | - Xihua Du
- School of Life Sciences, Shandong Normal University, Jinan 250014, China
| | - Zhangjie Nan
- Plant Science and Technology College, Beijing University of Agriculture, Beijing 102206, China
| | - Qingpeng Sun
- Plant Science and Technology College, Beijing University of Agriculture, Beijing 102206, China
| |
Collapse
|
28
|
Lew RR, Giblon RE, Lorenti MSH. The phenotype of a phospholipase C (plc-1) mutant in a filamentous fungus, Neurospora crassa. Fungal Genet Biol 2015. [PMID: 26212074 DOI: 10.1016/j.fgb.2015.07.007] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
In the filamentous fungus Neurospora crassa, phospholipase C may play a role in hyphal extension at the growing tips as part of a growth-sensing mechanism that activates calcium release from internal stores to mediate continued expansion of the hyphal tip. One candidate for a tip-localized phospholipase C is PLC-1. We characterized morphology and growth characteristics of a knockout mutant (KO plc-1) and a RIP mutated strain (RIP plc-1) (missense mutations and a nonsense mutation render the gene product non-functional). Growth and hyphal cytology of wildtype and KO plc-1 were similar, but the RIP plc-1 mutant grew slower and exhibited abnormal membrane structures at the hyphal tip, imaged using the fluorescence dye FM4-64. To test for causes of the slower growth of the RIP plc-1 mutant, we examined its physiological poise compared to wildtype and the KO plc-1 mutant. The electrical properties of all three strains and the electrogenic contribution of the plasma membrane H(+)-ATPase (identified by cyanide inhibition) were the same. Responses to high osmolarity were also similar. However, the RIP plc-1 mutant had a significantly lower turgor, a possible cause of its slower growth. While growth of all three strains was inhibited by the phospholipase C inhibitor 3-nitrocoumarin, the RIP plc-1 mutant did not exhibit hyphal bursting after addition of the inhibitor, observed in both wildtype and the KO plc-1 mutant. Although the plc-1 gene is not obligatory for tip growth, the phenotype of the RIP plc-1 mutant - abnormal tip cytology, lower turgor and resistance to inhibitor-induced hyphal bursting - suggest it does play a role in tip growth. The expression of a dysfunctional plc-1 gene may cause a shift to alternative mechanism(s) of growth sensing in hyphal extension.
Collapse
Affiliation(s)
- Roger R Lew
- York University, Biology Department, 4700 Keele Street, Toronto, ON M3J 1P3, Canada.
| | - Rachel E Giblon
- York University, Biology Department, 4700 Keele Street, Toronto, ON M3J 1P3, Canada
| | - Miranda S H Lorenti
- York University, Biology Department, 4700 Keele Street, Toronto, ON M3J 1P3, Canada
| |
Collapse
|
29
|
Zhou L, Lan W, Chen B, Fang W, Luan S. A calcium sensor-regulated protein kinase, CALCINEURIN B-LIKE PROTEIN-INTERACTING PROTEIN KINASE19, is required for pollen tube growth and polarity. PLANT PHYSIOLOGY 2015; 167:1351-60. [PMID: 25713341 PMCID: PMC4378171 DOI: 10.1104/pp.114.256065] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2014] [Accepted: 02/17/2015] [Indexed: 05/17/2023]
Abstract
Calcium plays an essential role in pollen tube tip growth. However, little is known concerning the molecular basis of the signaling pathways involved. Here, we identified Arabidopsis (Arabidopsis thaliana) CALCINEURIN B-LIKE PROTEIN-INTERACTING PROTEIN KINASE19 (CIPK19) as an important element to pollen tube growth through a functional survey for CIPK family members. The CIPK19 gene was specifically expressed in pollen grains and pollen tubes, and its overexpression induced severe loss of polarity in pollen tube growth. In the CIPK19 loss-of-function mutant, tube growth and polarity were significantly impaired, as demonstrated by both in vitro and in vivo pollen tube growth assays. Genetic analysis indicated that disruption of CIPK19 resulted in a male-specific transmission defect. Furthermore, loss of polarity induced by CIPK19 overexpression was associated with elevated cytosolic Ca2+ throughout the bulging tip, whereas LaCl3, a Ca2+ influx blocker, rescued CIPK19 overexpression-induced growth inhibition. Our results suggest that CIPK19 may be involved in maintaining Ca2+ homeostasis through its potential function in the modulation of Ca2+ influx.
Collapse
Affiliation(s)
- Liming Zhou
- College of Life Sciences, Fujian Agriculture and Forestry University, Fujian, Fuzhou 350002, China (L.Z., W.F.);Nanjing University-Nanjing Forestry University Joint Institute for Plant Molecular Biology, School of Life Sciences, Nanjing University, Nanjing 210093, China (W.L., S.L.);College of Biological Sciences, China Agricultural University, Beijing 100193, China (B.C.); andDepartment of Plant and Microbial Biology, University of California, Berkeley, California 94720 (S.L.)
| | - Wenzhi Lan
- College of Life Sciences, Fujian Agriculture and Forestry University, Fujian, Fuzhou 350002, China (L.Z., W.F.);Nanjing University-Nanjing Forestry University Joint Institute for Plant Molecular Biology, School of Life Sciences, Nanjing University, Nanjing 210093, China (W.L., S.L.);College of Biological Sciences, China Agricultural University, Beijing 100193, China (B.C.); andDepartment of Plant and Microbial Biology, University of California, Berkeley, California 94720 (S.L.)
| | - Binqing Chen
- College of Life Sciences, Fujian Agriculture and Forestry University, Fujian, Fuzhou 350002, China (L.Z., W.F.);Nanjing University-Nanjing Forestry University Joint Institute for Plant Molecular Biology, School of Life Sciences, Nanjing University, Nanjing 210093, China (W.L., S.L.);College of Biological Sciences, China Agricultural University, Beijing 100193, China (B.C.); andDepartment of Plant and Microbial Biology, University of California, Berkeley, California 94720 (S.L.)
| | - Wei Fang
- College of Life Sciences, Fujian Agriculture and Forestry University, Fujian, Fuzhou 350002, China (L.Z., W.F.);Nanjing University-Nanjing Forestry University Joint Institute for Plant Molecular Biology, School of Life Sciences, Nanjing University, Nanjing 210093, China (W.L., S.L.);College of Biological Sciences, China Agricultural University, Beijing 100193, China (B.C.); andDepartment of Plant and Microbial Biology, University of California, Berkeley, California 94720 (S.L.)
| | - Sheng Luan
- College of Life Sciences, Fujian Agriculture and Forestry University, Fujian, Fuzhou 350002, China (L.Z., W.F.);Nanjing University-Nanjing Forestry University Joint Institute for Plant Molecular Biology, School of Life Sciences, Nanjing University, Nanjing 210093, China (W.L., S.L.);College of Biological Sciences, China Agricultural University, Beijing 100193, China (B.C.); andDepartment of Plant and Microbial Biology, University of California, Berkeley, California 94720 (S.L.)
| |
Collapse
|
30
|
Chen J, Gutjahr C, Bleckmann A, Dresselhaus T. Calcium signaling during reproduction and biotrophic fungal interactions in plants. MOLECULAR PLANT 2015; 8:595-611. [PMID: 25660409 DOI: 10.1016/j.molp.2015.01.023] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2014] [Revised: 01/18/2015] [Accepted: 01/20/2015] [Indexed: 05/25/2023]
Abstract
Many recent studies have indicated that cellular communications during plant reproduction, fungal invasion, and defense involve identical or similar molecular players and mechanisms. Indeed, pollen tube invasion and sperm release shares many common features with infection of plant tissue by fungi and oomycetes, as a tip-growing intruder needs to communicate with the receptive cells to gain access into a cell and tissue. Depending on the compatibility between cells, interactions may result in defense, invasion, growth support, or cell death. Plant cells stimulated by both pollen tubes and fungal hyphae secrete, for example, small cysteine-rich proteins and receptor-like kinases are activated leading to intracellular signaling events such as the production of reactive oxygen species (ROS) and the generation of calcium (Ca(2+)) transients. The ubiquitous and versatile second messenger Ca(2+) thereafter plays a central and crucial role in modulating numerous downstream signaling processes. In stimulated cells, it elicits both fast and slow cellular responses depending on the shape, frequency, amplitude, and duration of the Ca(2+) transients. The various Ca(2+) signatures are transduced into cellular information via a battery of Ca(2+)-binding proteins. In this review, we focus on Ca(2+) signaling and discuss its occurrence during plant reproduction and interactions of plant cells with biotrophic filamentous microbes. The participation of Ca(2+) in ROS signaling pathways is also discussed.
Collapse
Affiliation(s)
- Junyi Chen
- Cell Biology and Plant Biochemistry, Biochemie-Zentrum Regensburg, University of Regensburg, Universitätsstraße 31, D-93053 Regensburg, Germany
| | - Caroline Gutjahr
- Faculty of Biology Genetics, Biocenter Martinsried, University of Munich (LMU), Grosshaderner Strasse 2-4, D-82152 Martinsried, Germany
| | - Andrea Bleckmann
- Cell Biology and Plant Biochemistry, Biochemie-Zentrum Regensburg, University of Regensburg, Universitätsstraße 31, D-93053 Regensburg, Germany
| | - Thomas Dresselhaus
- Cell Biology and Plant Biochemistry, Biochemie-Zentrum Regensburg, University of Regensburg, Universitätsstraße 31, D-93053 Regensburg, Germany.
| |
Collapse
|
31
|
Are Aquaporins the Missing Transmembrane Osmosensors? J Membr Biol 2015; 248:753-65. [PMID: 25791748 DOI: 10.1007/s00232-015-9790-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2014] [Accepted: 03/12/2015] [Indexed: 01/08/2023]
Abstract
Regulation of cell volume is central to homeostasis. It is assumed to begin with the detection of a change in water potential across the bounding membrane, but it is not clear how this is accomplished. While examples of general osmoreceptors (which sense osmotic pressure in one phase) and stretch-activated ion channels (which require swelling of a cell or organelle) are known, effective volume regulation requires true transmembrane osmosensors (TMOs) which directly detect a water potential difference spanning a membrane. At present, no TMO molecule has been unambiguously identified, and clear evidence for mammalian TMOs is notably lacking. In this paper, we set out a theory of TMOs which requires a water channel spanning the membrane that excludes the major osmotic solutes, responds directly without the need for any other process such as swelling, and signals to other molecules associated with the magnitude of changing osmotic differences. The most likely molecules that are fit for this purpose and which are also ubiquitous in eukaryotic cells are aquaporins (AQPs). We review experimental evidence from several systems which indicates that AQPs are essential elements in regulation and may be functioning as TMOs; i.e. the first step in an osmosensing sequence that signals osmotic imbalance in a cell or organelle. We extend this concept to several systems of current interest in which the cellular involvement of AQPs as simple water channels is puzzling or counter-intuitive. We suggest that, apart from regulatory volume changes in cells, AQPs may also be acting as TMOs in red cells, secretory granules and microorganisms.
Collapse
|
32
|
Saddhe AA, Kumar K. In silico identification and expression analysis of MscS like gene family in rice. ACTA ACUST UNITED AC 2015. [DOI: 10.1016/j.plgene.2014.12.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
|
33
|
Calcium is an organizer of cell polarity in plants. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2015; 1853:2168-72. [PMID: 25725133 DOI: 10.1016/j.bbamcr.2015.02.017] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2015] [Revised: 02/05/2015] [Accepted: 02/17/2015] [Indexed: 01/07/2023]
Abstract
Cell polarity is a fundamental property of pro- and eukaryotic cells. It is necessary for coordination of cell division, cell morphogenesis and signaling processes. How polarity is generated and maintained is a complex issue governed by interconnected feed-back regulations between small GTPase signaling and membrane tension-based signaling that controls membrane trafficking, and cytoskeleton organization and dynamics. Here, we will review the potential role for calcium as a crucial signal that connects and coordinates the respective processes during polarization processes in plants. This article is part of a Special Issue entitled: 13th European Symposium on Calcium.
Collapse
|
34
|
Felekis D, Vogler H, Mecja G, Muntwyler S, Nestorova A, Huang T, Sakar MS, Grossniklaus U, Nelson BJ. Real-time automated characterization of 3D morphology and mechanics of developing plant cells. Int J Rob Res 2015. [DOI: 10.1177/0278364914564231] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
In this article, we introduce the real-time cellular force microscope (RT-CFM), a high-throughput microrobotic platform for mechanical stimulation and characterization of single cells. We developed computer vision algorithms that fully automate the positioning of target cells and localization of the sensor tip. The control and acquisition architecture dramatically increases the accuracy, speed, and reliability of force measurements. Pollen tubes provide an ideal model system for the study of plant mechanics at the single-cell level. To quantitatively obtain the physical properties of the plant cell wall, we generated topography and stiffness measurements from 3D scans of living, growing pollen tubes. We report techniques for real-time monitoring and analysis of intracellular calcium fluxes during mechanical intervention. Our platform is compatible with various imaging systems and enables a powerful screening technology to facilitate biomechanical and morphological characterization of developing cells.
Collapse
Affiliation(s)
- Dimitrios Felekis
- Institute of Robotics and Intelligent Systems, ETH Zürich, Zürich, Switzerland
| | - Hannes Vogler
- Institute of Plant Biology and Zürich-Basel Plant Science Center, University of Zürich, Switzerland
| | - Geraldo Mecja
- Institute of Robotics and Intelligent Systems, ETH Zürich, Zürich, Switzerland
| | - Simon Muntwyler
- Institute of Robotics and Intelligent Systems, ETH Zürich, Zürich, Switzerland
| | - Anna Nestorova
- Institute of Plant Biology and Zürich-Basel Plant Science Center, University of Zürich, Switzerland
| | - Tianyun Huang
- Institute of Robotics and Intelligent Systems, ETH Zürich, Zürich, Switzerland
- Dalian University of Technology, School of Control Science and Engineering, Dalian Liaoning, China
- Liaoning University of Science and Technology, School of Electronics and Information Engineering, Anshan Liaoning, China
| | - Mahmut S. Sakar
- Institute of Robotics and Intelligent Systems, ETH Zürich, Zürich, Switzerland
| | - Ueli Grossniklaus
- Institute of Plant Biology and Zürich-Basel Plant Science Center, University of Zürich, Switzerland
| | - Bradley J. Nelson
- Institute of Robotics and Intelligent Systems, ETH Zürich, Zürich, Switzerland
| |
Collapse
|
35
|
Hamilton ES, Schlegel AM, Haswell ES. United in diversity: mechanosensitive ion channels in plants. ANNUAL REVIEW OF PLANT BIOLOGY 2014; 66:113-37. [PMID: 25494462 PMCID: PMC4470482 DOI: 10.1146/annurev-arplant-043014-114700] [Citation(s) in RCA: 125] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
Mechanosensitive (MS) ion channels are a common mechanism for perceiving and responding to mechanical force. This class of mechanoreceptors is capable of transducing membrane tension directly into ion flux. In plant systems, MS ion channels have been proposed to play a wide array of roles, from the perception of touch and gravity to the osmotic homeostasis of intracellular organelles. Three families of plant MS ion channels have been identified: the MscS-like (MSL), Mid1-complementing activity (MCA), and two-pore potassium (TPK) families. Channels from these families vary widely in structure and function, localize to multiple cellular compartments, and conduct chloride, calcium, and/or potassium ions. However, they are still likely to represent only a fraction of the MS ion channel diversity in plant systems.
Collapse
Affiliation(s)
- Eric S. Hamilton
- Department of Biology, Washington University in Saint Louis, Saint Louis, Missouri 63130
| | - Angela M. Schlegel
- Department of Biology, Washington University in Saint Louis, Saint Louis, Missouri 63130
| | - Elizabeth S. Haswell
- Department of Biology, Washington University in Saint Louis, Saint Louis, Missouri 63130
| |
Collapse
|
36
|
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.
Collapse
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.)
| |
Collapse
|
37
|
Potapova TV. Structural and functional organization of growing tips of Neurospora crassa Hyphae. BIOCHEMISTRY (MOSCOW) 2014; 79:593-607. [PMID: 25108323 DOI: 10.1134/s0006297914070025] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Data are presented on a variety of intracellular structures of the vegetative hyphae of the filamentous fungus Neurospora crassa and the involvement of these structures in the tip growth of the hyphae. Current ideas on the molecular and genetic mechanisms of tip growth and regulation of this process are considered. On the basis of comparison of data on behaviors of mitochondria and microtubules and data on the electrical heterogeneity of the hyphal apex, a hypothesis is proposed about a possible supervisory role of the longitudinal electric field in the structural and functional organization of growing tips of the N. crassa hyphae.
Collapse
Affiliation(s)
- T V Potapova
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119991, Russia.
| |
Collapse
|
38
|
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.
Collapse
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
| |
Collapse
|
39
|
Kaya H, Nakajima R, Iwano M, Kanaoka MM, Kimura S, Takeda S, Kawarazaki T, Senzaki E, Hamamura Y, Higashiyama T, Takayama S, Abe M, Kuchitsu K. Ca2+-activated reactive oxygen species production by Arabidopsis RbohH and RbohJ is essential for proper pollen tube tip growth. THE PLANT CELL 2014; 26:1069-80. [PMID: 24610725 PMCID: PMC4001369 DOI: 10.1105/tpc.113.120642] [Citation(s) in RCA: 182] [Impact Index Per Article: 18.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/11/2013] [Revised: 02/03/2014] [Accepted: 02/17/2014] [Indexed: 05/17/2023]
Abstract
In flowering plants, pollen germinates on the stigma and pollen tubes grow through the style to fertilize the ovules. Enzymatic production of reactive oxygen species (ROS) has been suggested to be involved in pollen tube tip growth. Here, we characterized the function and regulation of the NADPH oxidases RbohH and RbohJ (Respiratory burst oxidase homolog H and J) in pollen tubes in Arabidopsis thaliana. In the rbohH and rbohJ single mutants, pollen tube tip growth was comparable to that of the wild type; however, tip growth was severely impaired in the double mutant. In vivo imaging showed that ROS accumulation in the pollen tube was impaired in the double mutant. Both RbohH and RbohJ, which contain Ca(2+) binding EF-hand motifs, possessed Ca(2+)-induced ROS-producing activity and localized at the plasma membrane of the pollen tube tip. Point mutations in the EF-hand motifs impaired Ca(2+)-induced ROS production and complementation of the double mutant phenotype. We also showed that a protein phosphatase inhibitor enhanced the Ca(2+)-induced ROS-producing activity of RbohH and RbohJ, suggesting their synergistic activation by protein phosphorylation and Ca(2+). Our results suggest that ROS production by RbohH and RbohJ is essential for proper pollen tube tip growth, and furthermore, that Ca(2+)-induced ROS positive feedback regulation is conserved in the polarized cell growth to shape the long tubular cell.
Collapse
Affiliation(s)
- Hidetaka Kaya
- Department of Applied Biological Science, Tokyo
University of Science, Noda, Chiba 278-8510, Japan
- Department of Biological Science, Graduate School of
Science, University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Ryo Nakajima
- Department of Applied Biological Science, Tokyo
University of Science, Noda, Chiba 278-8510, Japan
| | - Megumi Iwano
- Graduate School of Biological Sciences, Nara Institute of
Science and Technology, Ikoma, Nara 630-0101, Japan
| | - Masahiro M. Kanaoka
- Division of Biological Science, Graduate School of
Science, Nagoya University, Nagoya, Aichi 464-8602, Japan
- Institute of Transformative Bio-Molecules, Nagoya
University, Nagoya, Aichi 464-8602, Japan
| | - Sachie Kimura
- Department of Applied Biological Science, Tokyo
University of Science, Noda, Chiba 278-8510, Japan
| | - Seiji Takeda
- Graduate School of Life and Environmental Sciences, Kyoto
Prefectural University, Soraku-gun, Kyoto 619-0244, Japan
| | - Tomoko Kawarazaki
- Department of Applied Biological Science, Tokyo
University of Science, Noda, Chiba 278-8510, Japan
| | - Eriko Senzaki
- Department of Applied Biological Science, Tokyo
University of Science, Noda, Chiba 278-8510, Japan
| | - Yuki Hamamura
- Division of Biological Science, Graduate School of
Science, Nagoya University, Nagoya, Aichi 464-8602, Japan
| | - Tetsuya Higashiyama
- Division of Biological Science, Graduate School of
Science, Nagoya University, Nagoya, Aichi 464-8602, Japan
- Institute of Transformative Bio-Molecules, Nagoya
University, Nagoya, Aichi 464-8602, Japan
- JST, ERATO, Higashiyama Live-Holonics Project, Nagoya
University, Nagoya, Aichi 464-8602, Japan
| | - Seiji Takayama
- Graduate School of Biological Sciences, Nara Institute of
Science and Technology, Ikoma, Nara 630-0101, Japan
| | - Mitsutomo Abe
- Department of Biological Science, Graduate School of
Science, University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Kazuyuki Kuchitsu
- Department of Applied Biological Science, Tokyo
University of Science, Noda, Chiba 278-8510, Japan
- Address correspondence to
| |
Collapse
|
40
|
Jiang X, Gao Y, Zhou H, Chen J, Wu J, Zhang S. Apoplastic calmodulin promotes self-incompatibility pollen tube growth by enhancing calcium influx and reactive oxygen species concentration in Pyrus pyrifolia. PLANT CELL REPORTS 2014; 33:255-63. [PMID: 24145911 DOI: 10.1007/s00299-013-1526-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2013] [Revised: 10/03/2013] [Accepted: 10/09/2013] [Indexed: 05/17/2023]
Abstract
Calmodulin (CaM) has been associated with various physiological and developmental processes in plants, including pollen tube growth. In this study, we showed that CaM regulated the pear pollen tube growth in a concentration-dependent bi-phasic response. Using a whole-cell patch-clamp configuration, we showed that apoplastic CaM induced a hyperpolarization-activated calcium ion (Ca²⁺) current, and anti-CaM largely inhibited this type of Ca²⁺ current. Moreover, upon anti-CaM treatment, the reactive oxygen species (ROS) concentration decreased and actin filaments depolymerized in the pollen tube. Interestingly, CaM could partially rescue the inhibition of self-incompatible pear pollen tube growth. This phenotype could be mediated by CaM-enhanced pollen plasma membrane Ca²⁺ current, tip-localized ROS concentration and stabilized actin filaments. These data indicated that Ca²⁺, ROS and actin filaments were involved with CaM in regulating pollen tube growth and provide a potential way for overcoming pear self-incompatibility.
Collapse
Affiliation(s)
- Xueting Jiang
- College of Horticulture, State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, No 6. Tongwei Road, Nanjing, 210095, China
| | | | | | | | | | | |
Collapse
|
41
|
Iwano M, Igarashi M, Tarutani Y, Kaothien-Nakayama P, Nakayama H, Moriyama H, Yakabe R, Entani T, Shimosato-Asano H, Ueki M, Tamiya G, Takayama S. A pollen coat-inducible autoinhibited Ca2+-ATPase expressed in stigmatic papilla cells is required for compatible pollination in the Brassicaceae. THE PLANT CELL 2014; 26:636-49. [PMID: 24569769 PMCID: PMC3967030 DOI: 10.1105/tpc.113.121350] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
In the Brassicaceae, intraspecific non-self pollen (compatible pollen) can germinate and grow into stigmatic papilla cells, while self-pollen or interspecific pollen is rejected at this stage. However, the mechanisms underlying this selective acceptance of compatible pollen remain unclear. Here, using a cell-impermeant calcium indicator, we showed that the compatible pollen coat contains signaling molecules that stimulate Ca(2+) export from the papilla cells. Transcriptome analyses of stigmas suggested that autoinhibited Ca(2+)-ATPase13 (ACA13) was induced after both compatible pollination and compatible pollen coat treatment. A complementation test using a yeast Saccharomyces cerevisiae strain lacking major Ca(2+) transport systems suggested that ACA13 indeed functions as an autoinhibited Ca(2+) transporter. ACA13 transcription increased in papilla cells and in transmitting tracts after pollination. ACA13 protein localized to the plasma membrane and to vesicles near the Golgi body and accumulated at the pollen tube penetration site after pollination. The stigma of a T-DNA insertion line of ACA13 exhibited reduced Ca(2+) export, as well as defects in compatible pollen germination and seed production. These findings suggest that stigmatic ACA13 functions in the export of Ca(2+) to the compatible pollen tube, which promotes successful fertilization.
Collapse
Affiliation(s)
- Megumi Iwano
- Graduate School of Biological Sciences, Nara Institute of Science and Technology, Ikoma, Nara 630-0192, Japan
- Address correspondence to
| | - Motoko Igarashi
- Graduate School of Biological Sciences, Nara Institute of Science and Technology, Ikoma, Nara 630-0192, Japan
| | - Yoshiaki Tarutani
- Division of Agricultural Genetics, Department of Integrated Genetics, National Institute of Genetics, Mishima, Shizuoka 411-8540, Japan
| | - Pulla Kaothien-Nakayama
- Graduate School of Biological Sciences, Nara Institute of Science and Technology, Ikoma, Nara 630-0192, Japan
| | - Hideki Nakayama
- Instutute of Environmental Studies, Graduate School of Fisheries Science and Environmental Studies, Nagasaki University, Nagasaki 852-8521, Japan
| | - Hideki Moriyama
- Graduate School of Biological Sciences, Nara Institute of Science and Technology, Ikoma, Nara 630-0192, Japan
| | - Ryo Yakabe
- Graduate School of Biological Sciences, Nara Institute of Science and Technology, Ikoma, Nara 630-0192, Japan
| | - Tetsuyuki Entani
- Graduate School of Biological Sciences, Nara Institute of Science and Technology, Ikoma, Nara 630-0192, Japan
| | - Hiroko Shimosato-Asano
- Graduate School of Biological Sciences, Nara Institute of Science and Technology, Ikoma, Nara 630-0192, Japan
| | - Masao Ueki
- Tohoku Medical Megabank Organization, Graduate School of Medicine, Tohoku University, Sendai 980-8573, Japan
| | - Gen Tamiya
- Tohoku Medical Megabank Organization, Graduate School of Medicine, Tohoku University, Sendai 980-8573, Japan
| | - Seiji Takayama
- Graduate School of Biological Sciences, Nara Institute of Science and Technology, Ikoma, Nara 630-0192, Japan
| |
Collapse
|
42
|
Scherer GFE, Quader H. Increased endocytosis of fluorescent phospholipid in tobacco pollen in microgravity and inhibition by verapamil. PLANT BIOLOGY (STUTTGART, GERMANY) 2014; 16 Suppl 1:107-12. [PMID: 23890120 DOI: 10.1111/plb.12061] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2013] [Accepted: 05/17/2013] [Indexed: 06/02/2023]
Abstract
Gravity sensing in plants occurs in specialised tissues, like in the columella in root tips or the endodermis in shoots. Generally, dense organelles, acting as statoliths, are thought to interact with the cytosekeleton and ion channels in gravitropism. We examined the possibility that tobacco pollen tubes (Nicotiana sylvestris) having an elaborate cytoskeleton could perceive gravity through interaction of the cytoskeleton and the endomembrane system and organelles. Using lipid endocytosis as a quantitative parameter, we show that endocytosis is increased transiently in microgravity within 3 min. This increase is inhibited by the calcium blocker verapamil, suggesting that calcium is lowered in the tip, which is known to increase endocytosis in the pollen tube.
Collapse
Affiliation(s)
- G F E Scherer
- Leibniz University Hannover, Institute for Ornamentals and Woody Plants Science, Abt. Molecular Developmental Physiology, Hannover, Germany
| | | |
Collapse
|
43
|
Shachar-Hill B, Hill AE, Powell J, Skepper JN, Shachar-Hill Y. Mercury-sensitive water channels as possible sensors of water potentials in pollen. JOURNAL OF EXPERIMENTAL BOTANY 2013; 64:5195-205. [PMID: 24098048 PMCID: PMC3830494 DOI: 10.1093/jxb/ert311] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
The growing pollen tube is central to plant reproduction and is a long-standing model for cellular tip growth in biology. Rapid osmotically driven growth is maintained under variable conditions, which requires osmosensing and regulation. This study explores the mechanism of water entry and the potential role of osmosensory regulation in maintaining pollen growth. The osmotic permeability of the plasmalemma of Lilium pollen tubes was measured from plasmolysis rates to be 1.32±0.31×10(-3) cm s(-1). Mercuric ions reduce this permeability by 65%. Simulations using an osmotic model of pollen tube growth predict that an osmosensor at the cell membrane controls pectin deposition at the cell tip; inhibiting the sensor is predicted to cause tip bursting due to cell wall thinning. It was found that adding mercury to growing pollen tubes caused such a bursting of the tips. The model indicates that lowering the osmotic permeability per se does not lead to bursting but rather to thickening of the tip. The time course of induced bursting showed no time lag and was independent of mercury concentration, compatible with a surface site of action. The submaximal bursting response to intermediate mercuric ion concentration was independent of the concentration of calcium ions, showing that bursting is not due to a competitive inhibition of calcium binding or entry. Bursting with the same time course was also shown by cells growing on potassium-free media, indicating that potassium channels (implicated in mechanosensing) are not involved in the bursting response. The possible involvement of mercury-sensitive water channels as osmosensors and current knowledge of these in pollen cells are discussed.
Collapse
Affiliation(s)
| | - Adrian E. Hill
- Department of Physiology, Development and Neuroscience, Cambridge University, Cambridge, UK
- * To whom correspondence should be addressed. E-mail:
| | - Janet Powell
- Multi-Imaging Centre, Cambridge University, Cambridge, UK
| | | | - Yair Shachar-Hill
- Department of Plant Biology, Plant Biology Building, Michigan State University, East Lansing, MI 48824-1312, USA
| |
Collapse
|
44
|
Bulychev AA, Alova AV, Bibikova TN. Strong alkalinization of Chara cell surface in the area of cell wall incision as an early event in mechanoperception. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2013; 1828:2359-69. [DOI: 10.1016/j.bbamem.2013.07.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2013] [Revised: 06/21/2013] [Accepted: 07/01/2013] [Indexed: 12/20/2022]
|
45
|
Monshausen GB, Haswell ES. A force of nature: molecular mechanisms of mechanoperception in plants. JOURNAL OF EXPERIMENTAL BOTANY 2013; 64:4663-80. [PMID: 23913953 PMCID: PMC3817949 DOI: 10.1093/jxb/ert204] [Citation(s) in RCA: 138] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
The ability to sense and respond to a wide variety of mechanical stimuli-gravity, touch, osmotic pressure, or the resistance of the cell wall-is a critical feature of every plant cell, whether or not it is specialized for mechanotransduction. Mechanoperceptive events are an essential part of plant life, required for normal growth and development at the cell, tissue, and whole-plant level and for the proper response to an array of biotic and abiotic stresses. One current challenge for plant mechanobiologists is to link these physiological responses to specific mechanoreceptors and signal transduction pathways. Here, we describe recent progress in the identification and characterization of two classes of putative mechanoreceptors, ion channels and receptor-like kinases. We also discuss how the secondary messenger Ca(2+) operates at the centre of many of these mechanical signal transduction pathways.
Collapse
Affiliation(s)
| | - Elizabeth S. Haswell
- Department of Biology, Washington University in St Louis, St Louis, MO 63130, USA
| |
Collapse
|
46
|
Chen DH, Acharya BR, Liu W, Zhang W. Interaction between Calcium and Actin in Guard Cell and Pollen Signaling Networks. PLANTS (BASEL, SWITZERLAND) 2013; 2:615-34. [PMID: 27137395 PMCID: PMC4844389 DOI: 10.3390/plants2040615] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 08/14/2013] [Revised: 09/25/2013] [Accepted: 09/26/2013] [Indexed: 12/17/2022]
Abstract
Calcium (Ca(2+)) plays important roles in plant growth, development, and signal transduction. It is a vital nutrient for plant physical design, such as cell wall and membrane, and also serves as a counter-cation for biochemical, inorganic, and organic anions, and more particularly, its concentration change in cytosol is a ubiquitous second messenger in plant physiological signaling in responses to developmental and environmental stimuli. Actin cytoskeleton is well known for its importance in cellular architecture maintenance and its significance in cytoplasmic streaming and cell division. In plant cell system, the actin dynamics is a process of polymerization and de-polymerization of globular actin and filamentous actin and that acts as an active regulator for calcium signaling by controlling calcium evoked physiological responses. The elucidation of the interaction between calcium and actin dynamics will be helpful for further investigation of plant cell signaling networks at molecular level. This review mainly focuses on the recent advances in understanding the interaction between the two aforementioned signaling components in two well-established model systems of plant, guard cell, and pollen.
Collapse
Affiliation(s)
- Dong-Hua Chen
- The Key Laboratory of Plant Cell Engineering and Germplasm Innovation, Ministry of Education, College of Life Sciences, Shandong University, Jinan 250100, Shandong, China.
| | - Biswa R Acharya
- Biology Department, Penn State University, University Park, PA 16802, USA.
| | - Wei Liu
- High-Tech Research Center, Shandong Academy of Agricultural Sciences, Key Laboratory of Genetic Improvement, Ecology and Physiology of Crops, Jinan 250100, Shandong, China.
| | - Wei Zhang
- The Key Laboratory of Plant Cell Engineering and Germplasm Innovation, Ministry of Education, College of Life Sciences, Shandong University, Jinan 250100, Shandong, China.
| |
Collapse
|
47
|
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.
Collapse
Affiliation(s)
- Peter K Hepler
- Biology Department, University of Massachusetts, Amherst, MA 01003, USA.
| | | | | |
Collapse
|
48
|
Zhao LN, Shen LK, Zhang WZ, Zhang W, Wang Y, Wu WH. Ca2+-dependent protein kinase11 and 24 modulate the activity of the inward rectifying K+ channels in Arabidopsis pollen tubes. THE PLANT CELL 2013; 25:649-61. [PMID: 23449501 PMCID: PMC3608784 DOI: 10.1105/tpc.112.103184] [Citation(s) in RCA: 87] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2012] [Revised: 01/03/2013] [Accepted: 02/07/2013] [Indexed: 05/18/2023]
Abstract
Potassium (K(+)) influx into pollen tubes via K(+) transporters is essential for pollen tube growth; however, the mechanism by which K(+) transporters are regulated in pollen tubes remains unknown. Here, we report that Arabidopsis thaliana Ca(2+)-dependent protein kinase11 (CPK11) and CPK24 are involved in Ca(2+)-dependent regulation of the inward K(+) (K(+)in) channels in pollen tubes. Using patch-clamp analysis, we demonstrated that K(+)in currents of pollen tube protoplasts were inhibited by elevated [Ca(2+)]cyt. However, disruption of CPK11 or CPK24 completely impaired the Ca(2+)-dependent inhibition of K(+)in currents and enhanced pollen tube growth. Moreover, the cpk11 cpk24 double mutant exhibited similar phenotypes as the corresponding single mutants, suggesting that these two CDPKs function in the same signaling pathway. Bimolecular fluorescence complementation and coimmunoprecipitation experiments showed that CPK11 could interact with CPK24 in vivo. Furthermore, CPK11 phosphorylated the N terminus of CPK24 in vitro, suggesting that these two CDPKs work together as part of a kinase cascade. Electrophysiological assays demonstrated that the Shaker pollen K(+)in channel is the main contributor to pollen tube K(+)in currents and acts as the downstream target of the CPK11-CPK24 pathway. We conclude that CPK11 and CPK24 together mediate the Ca(2+)-dependent inhibition of K(+)in channels and participate in the regulation of pollen tube growth in Arabidopsis.
Collapse
Affiliation(s)
| | | | | | | | - Yi Wang
- State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, National Plant Gene Research Centre, China Agricultural University, Beijing 100193, China
| | - Wei-Hua Wu
- State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, National Plant Gene Research Centre, China Agricultural University, Beijing 100193, China
| |
Collapse
|
49
|
Calcium as a Trigger and Regulator of Systemic Alarms and Signals along the Phloem Pathway. LONG-DISTANCE SYSTEMIC SIGNALING AND COMMUNICATION IN PLANTS 2013. [DOI: 10.1007/978-3-642-36470-9_18] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
|
50
|
Toyota M, Gilroy S. Gravitropism and mechanical signaling in plants. AMERICAN JOURNAL OF BOTANY 2013; 100:111-25. [PMID: 23281392 DOI: 10.3732/ajb.1200408] [Citation(s) in RCA: 81] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Mechanical stress is a critical signal affecting morphogenesis and growth and is caused by a large variety of environmental stimuli such as touch, wind, and gravity in addition to endogenous forces generated by growth. On the basis of studies dating from the early 19th century, the plant mechanical sensors and response components related to gravity can be divided into two types in terms of their temporal character: sensors of the transient stress of reorientation (phasic signaling) and sensors capable of monitoring and responding to the extended, continuous gravitropic signal for the duration of the tropic growth response (tonic signaling). In the case of transient stress, changes in the concentrations of ions in the cytoplasm play a central role in mechanosensing and are likely a key component of initial gravisensing. Potential candidates for mechanosensitive channels have been identified in Arabidopsis thaliana and may provide clues to these rapid, ionic gravisensing mechanisms. Continuous mechanical stress, on the other hand, may be sensed by other mechanisms in addition to the rapidly adapting mechnaosensitive channels of the phasic system. Sustaining such long-term responses may be through a network of biochemical signaling cascades that would therefore need to be maintained for the many hours of the growth response once they are triggered. However, classical physiological analyses and recent simulation studies also suggest involvement of the cytoskeleton in sensing/responding to long-term mechanoresponse independently of the biochemical signaling cascades triggered by initial graviperception events.
Collapse
Affiliation(s)
- Masatsugu Toyota
- Department of Botany, University of Wisconsin, Birge Hall, 430 Lincoln Drive, Madison, Wisconsin 53706, USA
| | | |
Collapse
|