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Yao Y, Yuan H, Liu D, Cheng L. Response of soybean root exudates and related metabolic pathways to low phosphorus stress. PLoS One 2024; 19:e0314256. [PMID: 39636902 PMCID: PMC11620397 DOI: 10.1371/journal.pone.0314256] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2024] [Accepted: 11/07/2024] [Indexed: 12/07/2024] Open
Abstract
Phosphorus (P) is an essential elemental nutrient required in high abundance for robust soybean growth and development. Low P stress negatively impacts plant physiological and biochemical processes, such as photosynthesis, respiration, and energy transfer. Soybean roots play key roles in plant adaptive responses to P stress and other soil-related environmental stressors. Study the changes in soybean root exudates and differences in related metabolic pathways under low phosphorus stress, analyzing the response mechanism of soybean roots to phosphorus stress from the perspective of root exudates, which provide a theoretical basis for further analyzing the physiological mechanism of phosphorus stress on soybean. In this study, soybean roots were exposed to three phosphate levels: 1 mg/L (P stress), 11 mg/L (P stress) and 31 mg/L (Normal P) for 10 days and 20 days, then root exudates were analyzed via ultra-high-performance liquid chromatography-mass spectrometry to identify effects of P stress on root metabolite profiles and associated metabolic pathways. Our results revealed that with increasing P stress severity and/or duration, soybean roots produced altered types, quantities, and increased numbers of exudate metabolites (DMs in the P1 group were primarily upregulated, whereas those in the P11 group were predominately downregulated) caused by changes in regulation of activities of numerous metabolic pathways. These pathways had functions related to environmental adaptation, energy metabolism, and scavenging of reactive oxygen species and primarily included amino acid, flavonoid, and nicotinate and nicotinamide metabolic pathways and pathways related to isoquinoline alkaloid biosynthesis, sugar catabolism, and phospholipid metabolism. These metabolites and metabolic pathways lay a foundation to support further investigations of physiological mechanisms underlying the soybean root response to P deficiency.
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Affiliation(s)
- Yubo Yao
- Institute of Industrial Crops, Heilongjiang Academy of Agricultural Sciences, Harbin, China
| | - Hongmei Yuan
- Institute of Industrial Crops, Heilongjiang Academy of Agricultural Sciences, Harbin, China
| | - Dandan Liu
- Institute of Industrial Crops, Heilongjiang Academy of Agricultural Sciences, Harbin, China
| | - Lili Cheng
- Institute of Industrial Crops, Heilongjiang Academy of Agricultural Sciences, Harbin, China
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2
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Zarreen F, Kumar K, Chakraborty S. Phosphoinositides in plant-pathogen interaction: trends and perspectives. STRESS BIOLOGY 2023; 3:4. [PMID: 37676371 PMCID: PMC10442044 DOI: 10.1007/s44154-023-00082-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2022] [Accepted: 02/15/2023] [Indexed: 09/08/2023]
Abstract
Phosphoinositides are important regulatory membrane lipids, with a role in plant development and cellular function. Emerging evidence indicates that phosphoinositides play crucial roles in plant defence and are also utilized by pathogens for infection. In this review, we highlight the role of phosphoinositides in plant-pathogen interaction and the implication of this remarkable convergence in the battle against plant diseases.
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Affiliation(s)
- Fauzia Zarreen
- Molecular Virology Laboratory, School of Life Science, Jawaharlal Nehru University, New Delhi, 110067, India
| | - Kamal Kumar
- Molecular Virology Laboratory, School of Life Science, Jawaharlal Nehru University, New Delhi, 110067, India
| | - Supriya Chakraborty
- Molecular Virology Laboratory, School of Life Science, Jawaharlal Nehru University, New Delhi, 110067, India.
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3
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Ali U, Lu S, Fadlalla T, Iqbal S, Yue H, Yang B, Hong Y, Wang X, Guo L. The functions of phospholipases and their hydrolysis products in plant growth, development and stress responses. Prog Lipid Res 2022; 86:101158. [PMID: 35134459 DOI: 10.1016/j.plipres.2022.101158] [Citation(s) in RCA: 58] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Revised: 01/31/2022] [Accepted: 01/31/2022] [Indexed: 12/15/2022]
Abstract
Cell membranes are the initial site of stimulus perception from environment and phospholipids are the basic and important components of cell membranes. Phospholipases hydrolyze membrane lipids to generate various cellular mediators. These phospholipase-derived products, such as diacylglycerol, phosphatidic acid, inositol phosphates, lysophopsholipids, and free fatty acids, act as second messengers, playing vital roles in signal transduction during plant growth, development, and stress responses. This review focuses on the structure, substrate specificities, reaction requirements, and acting mechanism of several phospholipase families. It will discuss their functional significance in plant growth, development, and stress responses. In addition, it will highlight some critical knowledge gaps in the action mechanism, metabolic and signaling roles of these phospholipases and their products in the context of plant growth, development and stress responses.
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Affiliation(s)
- Usman Ali
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan 430070, China; Hubei Hongshan Laboratory, Wuhan, 430070, China
| | - Shaoping Lu
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan 430070, China; Hubei Hongshan Laboratory, Wuhan, 430070, China
| | - Tarig Fadlalla
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan 430070, China
| | - Sidra Iqbal
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan 430070, China; Department of Agriculture, University of Swabi, Khyber Pakhtunkhwa, Pakistan
| | - Hong Yue
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan 430070, China; Hubei Hongshan Laboratory, Wuhan, 430070, China
| | - Bao Yang
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan 430070, China; Hubei Hongshan Laboratory, Wuhan, 430070, China
| | - Yueyun Hong
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan 430070, China; Hubei Hongshan Laboratory, Wuhan, 430070, China
| | - Xuemin Wang
- Department of Biology, University of Missouri-St. Louis, St. Louis, MO 63121, USA; Donald Danforth Plant Science Center, St. Louis, MO 63132, USA
| | - Liang Guo
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan 430070, China; Hubei Hongshan Laboratory, Wuhan, 430070, China.
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4
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Entanglement of Arabidopsis Seedlings to a Mesh Substrate under Microgravity Conditions in KIBO on the ISS. PLANTS 2022; 11:plants11070956. [PMID: 35406935 PMCID: PMC9003378 DOI: 10.3390/plants11070956] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/27/2022] [Revised: 03/27/2022] [Accepted: 03/29/2022] [Indexed: 11/17/2022]
Abstract
The International Space Station (ISS) provides a precious opportunity to study plant growth and development under microgravity (micro-G) conditions. In this study, four lines of Arabidopsis seeds (wild type, wild-type MCA1-GFP, mca1-knockout, and MCA1-overexpressed) were cultured on a nylon lace mesh placed on Gelrite-solidified MS-medium in the Japanese experiment module KIBO on the ISS, and the entanglement of roots with the mesh was examined under micro-G and 1-G conditions. We found that root entanglement with the mesh was enhanced, and root coiling was induced under the micro-G condition. This behavior was less pronounced in mca1-knockout seedlings, although MCA1-GFP distribution at the root tip of the seedlings was nearly the same in micro-G-grown seedlings and the ground control seedlings. Possible involvement of MCA1 in the root entanglement is discussed.
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Chin S, Blancaflor EB. Plant Gravitropism: From Mechanistic Insights into Plant Function on Earth to Plants Colonizing Other Worlds. Methods Mol Biol 2022; 2368:1-41. [PMID: 34647245 DOI: 10.1007/978-1-0716-1677-2_1] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Gravitropism, the growth of roots and shoots toward or away from the direction of gravity, has been studied for centuries. Such studies have not only led to a better understanding of the gravitropic process itself, but also paved new paths leading to deeper mechanistic insights into a wide range of research areas. These include hormone biology, cell signal transduction, regulation of gene expression, plant evolution, and plant interactions with a variety of environmental stimuli. In addition to contributions to basic knowledge about how plants function, there is accumulating evidence that gravitropism confers adaptive advantages to crops, particularly under marginal agricultural soils. Therefore, gravitropism is emerging as a breeding target for enhancing agricultural productivity. Moreover, research on gravitropism has spawned several studies on plant growth in microgravity that have enabled researchers to uncouple the effects of gravity from other tropisms. Although rapid progress on understanding gravitropism witnessed during the past decade continues to be driven by traditional molecular, physiological, and cell biological tools, these tools have been enriched by technological innovations in next-generation omics platforms and microgravity analog facilities. In this chapter, we review the field of gravitropism by highlighting recent landmark studies that have provided unique insights into this classic research topic while also discussing potential contributions to agriculture on Earth and beyond.
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Affiliation(s)
- Sabrina Chin
- Department of Botany, University of Wisconsin, Madison, WI, USA.
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The gravistimulation-induced very slow Ca 2+ increase in Arabidopsis seedlings requires MCA1, a Ca 2+-permeable mechanosensitive channel. Sci Rep 2021; 11:227. [PMID: 33420331 PMCID: PMC7794229 DOI: 10.1038/s41598-020-80733-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2020] [Accepted: 12/23/2020] [Indexed: 12/11/2022] Open
Abstract
Gravity is a critical environmental factor affecting the morphology and function of plants on Earth. Gravistimulation triggered by changes in the gravity vector induces an increase in the cytoplasmic free calcium ion concentration ([Ca2+]c) as an early process of gravity sensing; however, its role and molecular mechanism are still unclear. When seedlings of Arabidopsis thaliana expressing apoaequorin were rotated from the upright position to the upside-down position, a biphasic [Ca2+]c-increase composed of a fast-transient [Ca2+]c-increase followed by a slow [Ca2+]c-increase was observed. We find here a novel type [Ca2+]c-increase, designated a very slow [Ca2+]c-increase that is observed when the seedlings were rotated back to the upright position from the upside-down position. The very slow [Ca2+]c-increase was strongly attenuated in knockout seedlings defective in MCA1, a mechanosensitive Ca2+-permeable channel (MSCC), and was partially restored in MCA1-complemented seedlings. The mechanosensitive ion channel blocker, gadolinium, blocked the very slow [Ca2+]c-increase. This is the first report suggesting the possible involvement of MCA1 in an early event related to gravity sensing in Arabidopsis seedlings.
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Vandenbrink JP, Kiss JZ. Plant responses to gravity. Semin Cell Dev Biol 2019; 92:122-125. [DOI: 10.1016/j.semcdb.2019.03.011] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2018] [Accepted: 03/29/2019] [Indexed: 02/05/2023]
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8
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Kuo HF, Hsu YY, Lin WC, Chen KY, Munnik T, Brearley CA, Chiou TJ. Arabidopsis inositol phosphate kinases IPK1 and ITPK1 constitute a metabolic pathway in maintaining phosphate homeostasis. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2018. [PMID: 29779236 DOI: 10.1101/270355] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2018] [Revised: 05/02/2018] [Accepted: 05/09/2018] [Indexed: 05/27/2023]
Abstract
Emerging studies have suggested that there is a close link between inositol phosphate (InsP) metabolism and cellular phosphate (Pi ) homeostasis in eukaryotes; however, whether a common InsP species is deployed as an evolutionarily conserved metabolic messenger to mediate Pi signaling remains unknown. Here, using genetics and InsP profiling combined with Pi -starvation response (PSR) analysis in Arabidopsis thaliana, we showed that the kinase activity of inositol pentakisphosphate 2-kinase (IPK1), an enzyme required for phytate (inositol hexakisphosphate; InsP6 ) synthesis, is indispensable for maintaining Pi homeostasis under Pi -replete conditions, and inositol 1,3,4-trisphosphate 5/6-kinase 1 (ITPK1) plays an equivalent role. Although both ipk1-1 and itpk1 mutants exhibited decreased levels of InsP6 and diphosphoinositol pentakisphosphate (PP-InsP5 ; InsP7 ), disruption of another ITPK family enzyme, ITPK4, which correspondingly caused depletion of InsP6 and InsP7 , did not display similar Pi -related phenotypes, which precludes these InsP species from being effectors. Notably, the level of d/l-Ins(3,4,5,6)P4 was concurrently elevated in both ipk1-1 and itpk1 mutants, which showed a specific correlation with the misregulated Pi phenotypes. However, the level of d/l-Ins(3,4,5,6)P4 is not responsive to Pi starvation that instead manifests a shoot-specific increase in the InsP7 level. This study demonstrates a more nuanced picture of the intersection of InsP metabolism and Pi homeostasis and PSRs than has previously been elaborated, and additionally establishes intermediate steps to phytate biosynthesis in plant vegetative tissues.
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Affiliation(s)
- Hui-Fen Kuo
- Agricultural Biotechnology Research Center, Academia Sinica, Taipei, 115, Taiwan
| | - Yu-Ying Hsu
- Agricultural Biotechnology Research Center, Academia Sinica, Taipei, 115, Taiwan
| | - Wei-Chi Lin
- Agricultural Biotechnology Research Center, Academia Sinica, Taipei, 115, Taiwan
| | - Kai-Yu Chen
- Agricultural Biotechnology Research Center, Academia Sinica, Taipei, 115, Taiwan
| | - Teun Munnik
- Swammerdam Institute for Life Sciences, University of Amsterdam, Science Park 904, Amsterdam, 1098XH, The Netherlands
| | - Charles A Brearley
- School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich, NR4 7TJ, UK
| | - Tzyy-Jen Chiou
- Agricultural Biotechnology Research Center, Academia Sinica, Taipei, 115, Taiwan
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Kuo HF, Hsu YY, Lin WC, Chen KY, Munnik T, Brearley CA, Chiou TJ. Arabidopsis inositol phosphate kinases IPK1 and ITPK1 constitute a metabolic pathway in maintaining phosphate homeostasis. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2018; 95:613-630. [PMID: 29779236 DOI: 10.1111/tpj.13974] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2018] [Revised: 05/02/2018] [Accepted: 05/09/2018] [Indexed: 05/21/2023]
Abstract
Emerging studies have suggested that there is a close link between inositol phosphate (InsP) metabolism and cellular phosphate (Pi ) homeostasis in eukaryotes; however, whether a common InsP species is deployed as an evolutionarily conserved metabolic messenger to mediate Pi signaling remains unknown. Here, using genetics and InsP profiling combined with Pi -starvation response (PSR) analysis in Arabidopsis thaliana, we showed that the kinase activity of inositol pentakisphosphate 2-kinase (IPK1), an enzyme required for phytate (inositol hexakisphosphate; InsP6 ) synthesis, is indispensable for maintaining Pi homeostasis under Pi -replete conditions, and inositol 1,3,4-trisphosphate 5/6-kinase 1 (ITPK1) plays an equivalent role. Although both ipk1-1 and itpk1 mutants exhibited decreased levels of InsP6 and diphosphoinositol pentakisphosphate (PP-InsP5 ; InsP7 ), disruption of another ITPK family enzyme, ITPK4, which correspondingly caused depletion of InsP6 and InsP7 , did not display similar Pi -related phenotypes, which precludes these InsP species from being effectors. Notably, the level of d/l-Ins(3,4,5,6)P4 was concurrently elevated in both ipk1-1 and itpk1 mutants, which showed a specific correlation with the misregulated Pi phenotypes. However, the level of d/l-Ins(3,4,5,6)P4 is not responsive to Pi starvation that instead manifests a shoot-specific increase in the InsP7 level. This study demonstrates a more nuanced picture of the intersection of InsP metabolism and Pi homeostasis and PSRs than has previously been elaborated, and additionally establishes intermediate steps to phytate biosynthesis in plant vegetative tissues.
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Affiliation(s)
- Hui-Fen Kuo
- Agricultural Biotechnology Research Center, Academia Sinica, Taipei, 115, Taiwan
| | - Yu-Ying Hsu
- Agricultural Biotechnology Research Center, Academia Sinica, Taipei, 115, Taiwan
| | - Wei-Chi Lin
- Agricultural Biotechnology Research Center, Academia Sinica, Taipei, 115, Taiwan
| | - Kai-Yu Chen
- Agricultural Biotechnology Research Center, Academia Sinica, Taipei, 115, Taiwan
| | - Teun Munnik
- Swammerdam Institute for Life Sciences, University of Amsterdam, Science Park 904, Amsterdam, 1098XH, The Netherlands
| | - Charles A Brearley
- School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich, NR4 7TJ, UK
| | - Tzyy-Jen Chiou
- Agricultural Biotechnology Research Center, Academia Sinica, Taipei, 115, Taiwan
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10
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Liu YN, Lu XX, Chen D, Lu YP, Ren A, Shi L, Zhu J, Jiang AL, Yu HS, Zhao MW. Phospholipase D and phosphatidic acid mediate heat stress induced secondary metabolism in Ganoderma lucidum. Environ Microbiol 2017; 19:4657-4669. [PMID: 28892293 DOI: 10.1111/1462-2920.13928] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2017] [Revised: 08/15/2017] [Accepted: 09/04/2017] [Indexed: 12/12/2022]
Abstract
Phospholipid-mediated signal transduction plays a key role in responses to environmental changes, but little is known about the role of phospholipid signalling in microorganisms. Heat stress (HS) is one of the most important environmental factors. Our previous study found that HS could induce the biosynthesis of the secondary metabolites, ganoderic acids (GA). Here, we performed a comprehensive mass spectrometry-based analysis to investigate HS-induced lipid remodelling in Ganoderma lucidum. In particular, we observed a significant accumulation of phosphatidic acid (PA) on HS. Further genetic tests in which pld-silencing strains were constructed demonstrated that the accumulation of PA is dependent on HS-activated phospholipase D (PLD) hydrolysing phosphatidylethanolamine. Furthermore, we determined the role of PLD and PA in HS-induced secondary metabolism in G. lucidum. Exogenous 1-butanol, which decreased PLD-mediated formation of PA, reverses the increased GA biosynthesis that was elicited by HS. The pld-silenced strains partly blocked HS-induced GA biosynthesis, and this block can be reversed by adding PA. Taken together, our results suggest that PLD and PA are involved in the regulation of HS-induced secondary metabolism in G. lucidum. Our findings provide key insights into how microorganisms respond to heat stress and then consequently accumulate secondary metabolites by phospholipid remodelling.
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Affiliation(s)
- Yong-Nan Liu
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture, Microbiology Department, College of Life Sciences, Nanjing Agricultural University, Jiangsu, Nanjing 210095, People's Republic of China
| | - Xiao-Xiao Lu
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture, Microbiology Department, College of Life Sciences, Nanjing Agricultural University, Jiangsu, Nanjing 210095, People's Republic of China
| | - Dai Chen
- Biological experiment teaching center, College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, People's Republic of China
| | - Ya-Ping Lu
- Biological experiment teaching center, College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, People's Republic of China
| | - Ang Ren
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture, Microbiology Department, College of Life Sciences, Nanjing Agricultural University, Jiangsu, Nanjing 210095, People's Republic of China
| | - Liang Shi
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture, Microbiology Department, College of Life Sciences, Nanjing Agricultural University, Jiangsu, Nanjing 210095, People's Republic of China
| | - Jing Zhu
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture, Microbiology Department, College of Life Sciences, Nanjing Agricultural University, Jiangsu, Nanjing 210095, People's Republic of China
| | - Ai-Liang Jiang
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture, Microbiology Department, College of Life Sciences, Nanjing Agricultural University, Jiangsu, Nanjing 210095, People's Republic of China
| | - Han-Shou Yu
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture, Microbiology Department, College of Life Sciences, Nanjing Agricultural University, Jiangsu, Nanjing 210095, People's Republic of China
| | - Ming-Wen Zhao
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture, Microbiology Department, College of Life Sciences, Nanjing Agricultural University, Jiangsu, Nanjing 210095, People's Republic of China
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Abstract
The membranes of eukaryotic cells create hydrophobic barriers that control substance and information exchange between the inside and outside of cells and between cellular compartments. Besides their roles as membrane building blocks, some membrane lipids, such as phosphoinositides (PIs), also exert regulatory effects. Indeed, emerging evidence indicates that PIs play crucial roles in controlling polarity and growth in plants. Here, I highlight the key roles of PIs as important regulatory membrane lipids in plant development and function.
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Affiliation(s)
- Ingo Heilmann
- Department of Cellular Biochemistry, Institute for Biochemistry and Biotechnology, Martin-Luther-University Halle-Wittenberg, Kurt-Mothes-Str. 3, Halle (Saale) 06114, Germany
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12
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Singh M, Gupta A, Laxmi A. Striking the Right Chord: Signaling Enigma during Root Gravitropism. FRONTIERS IN PLANT SCIENCE 2017; 8:1304. [PMID: 28798760 PMCID: PMC5529344 DOI: 10.3389/fpls.2017.01304] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/2017] [Accepted: 07/11/2017] [Indexed: 05/29/2023]
Abstract
Plants being sessile can often be judged as passive acceptors of their environment. However, plants are actually even more active in responding to the factors from their surroundings. Plants do not have eyes, ears or vestibular system like animals, still they "know" which way is up and which way is down? This is facilitated by receptor molecules within plant which perceive changes in internal and external conditions such as light, touch, obstacles; and initiate signaling pathways that enable the plant to react. Plant responses that involve a definite and specific movement are called "tropic" responses. Perhaps the best known and studied tropisms are phototropism, i.e., response to light, and geotropism, i.e., response to gravity. A robust root system is vital for plant growth as it can provide physical anchorage to soil as well as absorb water, nutrients and essential minerals from soil efficiently. Gravitropic responses of both primary as well as lateral root thus become critical for plant growth and development. The molecular mechanisms of root gravitropism has been delved intensively, however, the mechanism behind how the potential energy of gravity stimulus converts into a biochemical signal in vascular plants is still unknown, due to which gravity sensing in plants still remains one of the most fascinating questions in molecular biology. Communications within plants occur through phytohormones and other chemical substances produced in plants which have a developmental or physiological effect on growth. Here, we review current knowledge of various intrinsic signaling mechanisms that modulate root gravitropism in order to point out the questions and emerging developments in plant directional growth responses. We are also discussing the roles of sugar signals and their interaction with phytohormone machinery, specifically in context of root directional responses.
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Affiliation(s)
- Manjul Singh
- National Institute of Plant Genome ResearchNew Delhi, India
- Interdisciplinary Centre for Plant Genomics, University of Delhi South CampusNew Delhi, India
| | - Aditi Gupta
- National Institute of Plant Genome ResearchNew Delhi, India
- Interdisciplinary Centre for Plant Genomics, University of Delhi South CampusNew Delhi, India
| | - Ashverya Laxmi
- National Institute of Plant Genome ResearchNew Delhi, India
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13
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Unda F, Kim H, Hefer C, Ralph J, Mansfield SD. Altering carbon allocation in hybrid poplar (Populus alba × grandidentata) impacts cell wall growth and development. PLANT BIOTECHNOLOGY JOURNAL 2017; 15:865-878. [PMID: 27998032 PMCID: PMC5466441 DOI: 10.1111/pbi.12682] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/2016] [Revised: 11/24/2016] [Accepted: 12/05/2016] [Indexed: 05/20/2023]
Abstract
Galactinol synthase is a pivotal enzyme involved in the synthesis of the raffinose family of oligosaccharides (RFOs) that function as transport carbohydrates in the phloem, as storage compounds in sink tissues and as soluble metabolites that combat both abiotic and biotic stress in several plant species. Hybrid poplar (Populus alba × grandidentata) overexpressing the Arabidopsis thaliana GolS3 (AtGolS3) gene showed clear effects on development; the extreme overexpressing lines were stunted and had cell wall traits characteristic of tension wood, whereas lines with only moderate up-regulation grew normally and had moderately altered secondary cell wall composition and ultrastructure. Stem cross-sections of the developing xylem revealed a significant increase in the number of vessels, as well as the clear presence of a G-layer in the fibres. Furthermore, AtGolS3-OE lines possessed higher cellulose and lower lignin contents, an increase in cellulose crystallinity, and significantly altered hemicellulose-derived carbohydrates, notably manifested by their mannose and xylose contents. In addition, the transgenic plants displayed elevated xylem starch content. Transcriptome interrogation of the transgenic plants showed a significant up-regulation of genes involved in the synthesis of myo-inositol, along with genes involved in sucrose degradation. The results suggest that the overexpression of GolS and its product galactinol may serve as a molecular signal that initiates metabolic changes, culminating in a change in cell wall development and potentially the formation of tension wood.
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Affiliation(s)
- Faride Unda
- Department of Wood ScienceUniversity of British ColumbiaVancouverBCCanada
| | - Hoon Kim
- Department of BiochemistryUniversity of WisconsinMadisonWIUSA
- Department of Energy Great Lakes Bioenergy Research CenterWisconsin Energy InstituteMadisonWIUSA
| | - Charles Hefer
- Biotechnology PlatformAgricultural Research CouncilPretoriaSouth Africa
| | - John Ralph
- Department of BiochemistryUniversity of WisconsinMadisonWIUSA
- Department of Energy Great Lakes Bioenergy Research CenterWisconsin Energy InstituteMadisonWIUSA
| | - Shawn D. Mansfield
- Department of Wood ScienceUniversity of British ColumbiaVancouverBCCanada
- Department of Energy Great Lakes Bioenergy Research CenterWisconsin Energy InstituteMadisonWIUSA
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14
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Hong Y, Zhao J, Guo L, Kim SC, Deng X, Wang G, Zhang G, Li M, Wang X. Plant phospholipases D and C and their diverse functions in stress responses. Prog Lipid Res 2016; 62:55-74. [DOI: 10.1016/j.plipres.2016.01.002] [Citation(s) in RCA: 214] [Impact Index Per Article: 23.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2015] [Revised: 12/23/2015] [Accepted: 01/01/2016] [Indexed: 12/25/2022]
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15
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Heilmann I. Plant phosphoinositide signaling - dynamics on demand. Biochim Biophys Acta Mol Cell Biol Lipids 2016; 1861:1345-1351. [PMID: 26924252 DOI: 10.1016/j.bbalip.2016.02.013] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2016] [Revised: 02/18/2016] [Accepted: 02/19/2016] [Indexed: 10/22/2022]
Abstract
Eukaryotic membranes contain small amounts of lipids with regulatory roles. An important class of such regulatory lipids are phosphoinositides (PIs). Within membranes, PIs serve as recruitment signals, as regulators of membrane protein function or as precursors for second messenger production, thereby influencing a multitude of cellular processes with key importance for plant function and development. Plant PIs occur locally and transiently within membrane microdomains, and their abundance is strictly controlled. To understand the functions of the plant PI-network it is important to understand not only downstream PI-effects, but also to identify and characterize factors contributing to dynamic PI formation. This article is part of a Special Issue entitled: Plant Lipid Biology edited by Kent D. Chapman and Ivo Feussner.
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Affiliation(s)
- Ingo Heilmann
- Department of Cellular Biochemistry, Institute for Biochemistry and Biotechnology, Martin-Luther-University Halle-Wittenberg, Kurt-Mothes-Str. 3, 06120 Halle (Saale), Germany.
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Schüler O, Hemmersbach R, Böhmer M. A Bird's-Eye View of Molecular Changes in Plant Gravitropism Using Omics Techniques. FRONTIERS IN PLANT SCIENCE 2015; 6:1176. [PMID: 26734055 PMCID: PMC4689802 DOI: 10.3389/fpls.2015.01176] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/12/2015] [Accepted: 12/08/2015] [Indexed: 05/10/2023]
Abstract
During evolution, plants have developed mechanisms to adapt to a variety of environmental stresses, including drought, high salinity, changes in carbon dioxide levels and pathogens. Central signaling hubs and pathways that are regulated in response to these stimuli have been identified. In contrast to these well studied environmental stimuli, changes in transcript, protein and metabolite levels in response to a gravitational stimulus are less well understood. Amyloplasts, localized in statocytes of the root tip, in mesophyll cells of coleoptiles and in the elongation zone of the growing internodes comprise statoliths in higher plants. Deviations of the statocytes with respect to the earthly gravity vector lead to a displacement of statoliths relative to the cell due to their inertia and thus to gravity perception. Downstream signaling events, including the conversion from the biophysical signal of sedimentation of distinct heavy mass to a biochemical signal, however, remain elusive. More recently, technical advances, including clinostats, drop towers, parabolic flights, satellites, and the International Space Station, allowed researchers to study the effect of altered gravity conditions - real and simulated micro- as well as hypergravity on plants. This allows for a unique opportunity to study plant responses to a purely anthropogenic stress for which no evolutionary program exists. Furthermore, the requirement for plants as food and oxygen sources during prolonged manned space explorations led to an increased interest in the identi-fication of genes involved in the adaptation of plants to microgravity. Transcriptomic, proteomic, phosphoproteomic, and metabolomic profiling strategies provide a sensitive high-throughput approach to identify biochemical alterations in response to changes with respect to the influence of the gravitational vector and thus the acting gravitational force on the transcript, protein and metabolite level. This review aims at summarizing recent experimental approaches and discusses major observations.
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Affiliation(s)
- Oliver Schüler
- Institute of Aerospace Medicine, Gravitational Biology, German Aerospace CenterCologne, Germany
- Institute of Plant Biology and Biotechnology, Westfälische Wilhelms UniversitätMünster, Germany
| | - Ruth Hemmersbach
- Institute of Aerospace Medicine, Gravitational Biology, German Aerospace CenterCologne, Germany
| | - Maik Böhmer
- Institute of Plant Biology and Biotechnology, Westfälische Wilhelms UniversitätMünster, Germany
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Aggarwal S, Shukla V, Bhati KK, Kaur M, Sharma S, Singh A, Mantri S, Pandey AK. Hormonal Regulation and Expression Profiles of Wheat Genes Involved during Phytic Acid Biosynthesis Pathway. PLANTS 2015; 4:298-319. [PMID: 27135330 PMCID: PMC4844322 DOI: 10.3390/plants4020298] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/28/2015] [Revised: 05/26/2015] [Accepted: 06/01/2015] [Indexed: 11/16/2022]
Abstract
Phytic acid (PA) biosynthesis pathway genes were reported from multiple crop species. PA accumulation was enhanced during grain filling and at that time, hormones like Abscisic acid (ABA) and Gibberellic acid (GA3) interplay to control the process of seed development. Regulation of wheat PA pathway genes has not yet been reported in seeds. In an attempt to find the clues for the regulation by hormones, the promoter region of wheat PA pathway genes was analyzed for the presence of cis-elements. Multiple cis-elements of those known to be involved for ABA, GA3, salicylic acid (SA), and cAMP sensing were identified in the promoters of PA pathway genes. Eight genes (TaIMP, TaITPK1-4, TaPLC1, TaIPK2 and TaIPK1) involved in the wheat PA biosynthesis pathway were selected for the expression studies. The temporal expression response was studied in seeds treated with ABA and GA3 using quantitative real time PCR. Our results suggested that exogenous application of ABA induces few PA pathway genes in wheat grains. Comparison of expression profiles for PA pathway for GA3 and ABA suggested the antagonistic regulation of certain genes. Additionally, to reveal stress responses of wheat PA pathway genes, expression was also studied in the presence of SA and cAMP. Results suggested SA specific differential expression of few genes, whereas, overall repression of genes was observed in cAMP treated samples. This study is an effort to understand the regulation of PA biosynthesis genes in wheat.
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Affiliation(s)
- Sipla Aggarwal
- Department of Biotechnology, National Agri-Food Biotechnology Institute, C-127 Industrial Area, S.A.S-Nagar, Phase-8, Mohali, Punjab 160071, India.
| | - Vishnu Shukla
- Department of Biotechnology, National Agri-Food Biotechnology Institute, C-127 Industrial Area, S.A.S-Nagar, Phase-8, Mohali, Punjab 160071, India.
| | - Kaushal Kumar Bhati
- Department of Biotechnology, National Agri-Food Biotechnology Institute, C-127 Industrial Area, S.A.S-Nagar, Phase-8, Mohali, Punjab 160071, India.
| | - Mandeep Kaur
- Department of Biotechnology, National Agri-Food Biotechnology Institute, C-127 Industrial Area, S.A.S-Nagar, Phase-8, Mohali, Punjab 160071, India.
| | - Shivani Sharma
- Department of Biotechnology, National Agri-Food Biotechnology Institute, C-127 Industrial Area, S.A.S-Nagar, Phase-8, Mohali, Punjab 160071, India.
| | - Anuradha Singh
- Department of Biotechnology, National Agri-Food Biotechnology Institute, C-127 Industrial Area, S.A.S-Nagar, Phase-8, Mohali, Punjab 160071, India.
| | - Shrikant Mantri
- Department of Biotechnology, National Agri-Food Biotechnology Institute, C-127 Industrial Area, S.A.S-Nagar, Phase-8, Mohali, Punjab 160071, India.
| | - Ajay Kumar Pandey
- Department of Biotechnology, National Agri-Food Biotechnology Institute, C-127 Industrial Area, S.A.S-Nagar, Phase-8, Mohali, Punjab 160071, India.
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Žádníková P, Smet D, Zhu Q, Straeten DVD, Benková E. Strategies of seedlings to overcome their sessile nature: auxin in mobility control. FRONTIERS IN PLANT SCIENCE 2015; 6:218. [PMID: 25926839 PMCID: PMC4396199 DOI: 10.3389/fpls.2015.00218] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2014] [Accepted: 03/19/2015] [Indexed: 05/21/2023]
Abstract
Plants are sessile organisms that are permanently restricted to their site of germination. To compensate for their lack of mobility, plants evolved unique mechanisms enabling them to rapidly react to ever changing environmental conditions and flexibly adapt their postembryonic developmental program. A prominent demonstration of this developmental plasticity is their ability to bend organs in order to reach the position most optimal for growth and utilization of light, nutrients, and other resources. Shortly after germination, dicotyledonous seedlings form a bended structure, the so-called apical hook, to protect the delicate shoot meristem and cotyledons from damage when penetrating through the soil. Upon perception of a light stimulus, the apical hook rapidly opens and the photomorphogenic developmental program is activated. After germination, plant organs are able to align their growth with the light source and adopt the most favorable orientation through bending, in a process named phototropism. On the other hand, when roots and shoots are diverted from their upright orientation, they immediately detect a change in the gravity vector and bend to maintain a vertical growth direction. Noteworthy, despite the diversity of external stimuli perceived by different plant organs, all plant tropic movements share a common mechanistic basis: differential cell growth. In our review, we will discuss the molecular principles underlying various tropic responses with the focus on mechanisms mediating the perception of external signals, transduction cascades and downstream responses that regulate differential cell growth and consequently, organ bending. In particular, we highlight common and specific features of regulatory pathways in control of the bending of organs and a role for the plant hormone auxin as a key regulatory component.
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Affiliation(s)
- Petra Žádníková
- Department of Plant Systems Biology, Flanders Institute for Biotechnology, GhentBelgium
- Department of Plant Biotechnology and Bioinformatics, Ghent University, GhentBelgium
| | - Dajo Smet
- Department of Physiology, Laboratory of Functional Plant Biology, Ghent University, GhentBelgium
| | - Qiang Zhu
- Institute of Science and Technology Austria, KlosterneuburgAustria
| | | | - Eva Benková
- Institute of Science and Technology Austria, KlosterneuburgAustria
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19
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Sato EM, Hijazi H, Bennett MJ, Vissenberg K, Swarup R. New insights into root gravitropic signalling. JOURNAL OF EXPERIMENTAL BOTANY 2015; 66:2155-65. [PMID: 25547917 PMCID: PMC4986716 DOI: 10.1093/jxb/eru515] [Citation(s) in RCA: 102] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2014] [Revised: 12/01/2014] [Accepted: 12/03/2014] [Indexed: 05/18/2023]
Abstract
An important feature of plants is the ability to adapt their growth towards or away from external stimuli such as light, water, temperature, and gravity. These responsive plant growth movements are called tropisms and they contribute to the plant's survival and reproduction. Roots modulate their growth towards gravity to exploit the soil for water and nutrient uptake, and to provide anchorage. The physiological process of root gravitropism comprises gravity perception, signal transmission, growth response, and the re-establishment of normal growth. Gravity perception is best explained by the starch-statolith hypothesis that states that dense starch-filled amyloplasts or statoliths within columella cells sediment in the direction of gravity, resulting in the generation of a signal that causes asymmetric growth. Though little is known about the gravity receptor(s), the role of auxin linking gravity sensing to the response is well established. Auxin influx and efflux carriers facilitate creation of a differential auxin gradient between the upper and lower side of gravistimulated roots. This asymmetric auxin gradient causes differential growth responses in the graviresponding tissue of the elongation zone, leading to root curvature. Cell biological and mathematical modelling approaches suggest that the root gravitropic response begins within minutes of a gravity stimulus, triggering genomic and non-genomic responses. This review discusses recent advances in our understanding of root gravitropism in Arabidopsis thaliana and identifies current challenges and future perspectives.
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Affiliation(s)
- Ethel Mendocilla Sato
- University of Antwerp, Biology Department, Plant Growth and Development, Groenenborgerlaan 171, 2020 Antwerpen, Belgium Centre for Plant Integrative Biology, University of Nottingham, Sutton Bonington LE12 5RD, UK
| | - Hussein Hijazi
- Centre for Plant Integrative Biology, University of Nottingham, Sutton Bonington LE12 5RD, UK
| | - Malcolm J Bennett
- Centre for Plant Integrative Biology, University of Nottingham, Sutton Bonington LE12 5RD, UK
| | - Kris Vissenberg
- University of Antwerp, Biology Department, Plant Growth and Development, Groenenborgerlaan 171, 2020 Antwerpen, Belgium
| | - Ranjan Swarup
- Centre for Plant Integrative Biology, University of Nottingham, Sutton Bonington LE12 5RD, UK
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20
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Desai M, Rangarajan P, Donahue JL, Williams SP, Land ES, Mandal MK, Phillippy BQ, Perera IY, Raboy V, Gillaspy GE. Two inositol hexakisphosphate kinases drive inositol pyrophosphate synthesis in plants. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2014; 80:642-53. [PMID: 25231822 DOI: 10.1111/tpj.12669] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2014] [Revised: 08/22/2014] [Accepted: 08/27/2014] [Indexed: 05/24/2023]
Abstract
Inositol pyrophosphates are unique cellular signaling molecules with recently discovered roles in energy sensing and metabolism. Studies in eukaryotes have revealed that these compounds have a rapid turnover, and thus only small amounts accumulate. Inositol pyrophosphates have not been the subject of investigation in plants even though seeds produce large amounts of their precursor, myo-inositol hexakisphosphate (InsP6 ). Here, we report that Arabidopsis and maize InsP6 transporter mutants have elevated levels of inositol pyrophosphates in their seed, providing unequivocal identification of their presence in plant tissues. We also show that plant seeds store a little over 1% of their inositol phosphate pool as InsP7 and InsP8 . Many tissues, including, seed, seedlings, roots and leaves accumulate InsP7 and InsP8 , thus synthesis is not confined to tissues with high InsP6 . We have identified two highly similar Arabidopsis genes, AtVip1 and AtVip2, which are orthologous to the yeast and mammalian VIP kinases. Both AtVip1 and AtVip2 encode proteins capable of restoring InsP7 synthesis in yeast mutants, thus AtVip1 and AtVip2 can function as bonafide InsP6 kinases. AtVip1 and AtVip2 are differentially expressed in plant tissues, suggesting non-redundant or non-overlapping functions in plants. These results contribute to our knowledge of inositol phosphate metabolism and will lay a foundation for understanding the role of InsP7 and InsP8 in plants.
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Affiliation(s)
- Mintu Desai
- Department of Plant and Microbial Biology, North Carolina State University, Room 4209, Gardner Hall, Raleigh, NC 27695, USA
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21
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Plant phosphoinositides-complex networks controlling growth and adaptation. Biochim Biophys Acta Mol Cell Biol Lipids 2014; 1851:759-69. [PMID: 25280638 DOI: 10.1016/j.bbalip.2014.09.018] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2014] [Revised: 09/22/2014] [Accepted: 09/23/2014] [Indexed: 11/24/2022]
Abstract
Plants differ in many ways from mammals or yeast. However, plants employ phosphoinositides for the regulation of essential cellular functions as do all other eukaryotes. In recent years the plant phosphoinositide system has been linked to the control of cell polarity. Phosphoinositides are also implicated in plant adaptive responses to changing environmental conditions. The current understanding is that plant phosphoinositides control membrane trafficking, ion channels and the cytoskeleton in similar ways as in other eukaryotic systems, but adapted to meet plant cellular requirements and with some plant-specific features. In addition, the formation of soluble inositol polyphosphates from phosphoinositides is important for the perception of important phytohormones, as the relevant receptor proteins contain such molecules as structural cofactors. Overall, the essential nature of phosphoinositides in plants has been established. Still, the complexity of the phosphoinositide networks in plant cells is only emerging and invites further study of its molecular details. This article is part of a special issue entitled Phosphoinositides.
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22
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Tatsumi H, Toyota M, Furuichi T, Sokabe M. Calcium mobilizations in response to changes in the gravity vector in Arabidopsis seedlings: possible cellular mechanisms. PLANT SIGNALING & BEHAVIOR 2014; 9:e29099. [PMID: 25763612 PMCID: PMC4203510 DOI: 10.4161/psb.29099] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/2014] [Revised: 05/02/2014] [Accepted: 05/02/2014] [Indexed: 05/11/2023]
Abstract
Gravity influences the growth direction of higher plants. Changes in the gravity vector (gravistimulation) immediately promote the increase in the cytoplasmic free calcium ion concentration ([Ca(2+)]c) in Arabidopsis (Arabidopsis thaliana) seedlings. When the seedlings are gravistimulated by reorientation at 180°, a transient two peaked (biphasic) [Ca(2+)]c-increase arises in their hypocotyl and petioles. Parabolic flights (PFs) can generate a variety of gravity-stimuli, and enables us to measure gravity-induced [Ca(2+)]c-increases without specimen rotation, which demonstrate that Arabidopsis seedlings possess a rapid gravity-sensing mechanism linearly transducing a wide range of gravitational changes into Ca(2+) signals on a sub-second timescale. Hypergravity by centrifugation (20 g or 300 g) also induces similar transient [Ca(2+)]c-increases. In this review, we propose models for possible cellular processes of the garavi-stimulus-induced [Ca(2+)]c-increase, and evaluate those by examining whether the model fits well with the kinetic parameters derived from the [Ca(2+)]c-increases obtained by applying gravistimulus with different amplitudes and time sequences.
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Affiliation(s)
- Hitoshi Tatsumi
- Nagoya University Graduate School of Medicine; Nagoya, Japan
| | - Masatsugu Toyota
- Department of Botany; University of Wisconsin; Madison, WI USA
- Precursory Research for Embryonic Science and Technology (PRESTO); Japan Science and Technology Agency (JST); Kawaguchi, Saitama, Japan
| | - Takuya Furuichi
- Department of Health and Nutrition; Gifu Women’s University; Gifu, Japan
| | - Masahiro Sokabe
- Nagoya University Graduate School of Medicine; Nagoya, Japan
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23
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Taniguchi M, Nakamura M, Tasaka M, Morita MT. Identification of gravitropic response indicator genes in Arabidopsis inflorescence stems. PLANT SIGNALING & BEHAVIOR 2014; 9:e29570. [PMID: 25763694 PMCID: PMC4203507 DOI: 10.4161/psb.29570] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Differential organ growth during gravitropic response is caused by differential accumulation of auxin, that is, relative higher auxin concentration in lower flanks than in upper flanks of responding organs. Auxin responsive reporter systems such as DR5::GUS and DR5::GFP have usually been used as indicators of gravitropic response in roots and hypocotyls of Arabidopsis. However, in the inflorescence stems, the reporter systems don't work well to monitor gravitropic response. Here, we aim to certify appropriate gravitropic response indicators (GRIs) in inflorescence stems. We performed microarray analysis comparing gene expression profiles between upper and lower flanks of Arabidopsis inflorescence stems after gravistimulation. Thirty genes showed > 2-fold differentially increased expression in lower flanks at 30 min, of which 19 were auxin response genes. We focused on IAA5 and IAA2 and verified whether they are appropriate GRIs by real-time qRT-PCR analyses. Transcript levels of IAA5 and IAA2 were remarkably higher in lower flanks than in upper flanks after gravistimulation. The biased IAA5 or IAA2 expression is disappeared in sgr2-1 mutant which is defective in gravity perception, indicating that gravity perception process is essential for formation of the biased gene expression during gravitropism. IAA5 expression was remarkably increased in lower flanks at 30 min after gravistimulation, whereas IAA2 expression was gradually decreased in upper flanks in a time-dependent manner. Therefore, we conclude that IAA5 is a sensitive GRI to monitor asymmetric auxin signaling caused by gravistimulation in Arabidopsis inflorescence stems.
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Affiliation(s)
- Masatoshi Taniguchi
- Graduate School of Bioagricultural Sciences; Nagoya University; Furo-cho, Chikusa-ku, Nagoya, Japan
| | - Moritaka Nakamura
- Institute of Biochemistry and Biology; Plant Physiology; University of Potsdam; Potsdam-Golm, Germany
| | - Masao Tasaka
- Graduate School of Biological Sciences; Nara Institute of Science and Technology; Takayama, Ikoma, Nara, Japan
| | - Miyo Terao Morita
- Graduate School of Bioagricultural Sciences; Nagoya University; Furo-cho, Chikusa-ku, Nagoya, Japan
- Correspondence to: Miyo Terao Morita,
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Ischebeck T, Werner S, Krishnamoorthy P, Lerche J, Meijón M, Stenzel I, Löfke C, Wiessner T, Im YJ, Perera IY, Iven T, Feussner I, Busch W, Boss WF, Teichmann T, Hause B, Persson S, Heilmann I. Phosphatidylinositol 4,5-bisphosphate influences PIN polarization by controlling clathrin-mediated membrane trafficking in Arabidopsis. THE PLANT CELL 2013; 25:4894-911. [PMID: 24326589 PMCID: PMC3903994 DOI: 10.1105/tpc.113.116582] [Citation(s) in RCA: 79] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2013] [Revised: 09/22/2013] [Accepted: 10/15/2013] [Indexed: 05/19/2023]
Abstract
The functions of the minor phospholipid phosphatidylinositol-4,5-bisphosphate [PtdIns(4,5)P2] during vegetative plant growth remain obscure. Here, we targeted two related phosphatidylinositol 4-phosphate 5-kinases (PI4P 5-kinases) PIP5K1 and PIP5K2, which are expressed ubiquitously in Arabidopsis thaliana. A pip5k1 pip5k2 double mutant with reduced PtdIns(4,5)P2 levels showed dwarf stature and phenotypes suggesting defects in auxin distribution. The roots of the pip5k1 pip5k2 double mutant had normal auxin levels but reduced auxin transport and altered distribution. Fluorescence-tagged auxin efflux carriers PIN-FORMED (PIN1)-green fluorescent protein (GFP) and PIN2-GFP displayed abnormal, partially apolar distribution. Furthermore, fewer brefeldin A-induced endosomal bodies decorated by PIN1-GFP or PIN2-GFP formed in pip5k1 pip5k2 mutants. Inducible overexpressor lines for PIP5K1 or PIP5K2 also exhibited phenotypes indicating misregulation of auxin-dependent processes, and immunolocalization showed reduced membrane association of PIN1 and PIN2. PIN cycling and polarization require clathrin-mediated endocytosis and labeled clathrin light chain also displayed altered localization patterns in the pip5k1 pip5k2 double mutant, consistent with a role for PtdIns(4,5)P2 in the regulation of clathrin-mediated endocytosis. Further biochemical tests on subcellular fractions enriched for clathrin-coated vesicles (CCVs) indicated that pip5k1 and pip5k2 mutants have reduced CCV-associated PI4P 5-kinase activity. Together, the data indicate an important role for PtdIns(4,5)P2 in the control of clathrin dynamics and in auxin distribution in Arabidopsis.
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Affiliation(s)
- Till Ischebeck
- Department of Plant Biochemistry, Albrecht-von-Haller-Institute for Plant Sciences, Georg-August-University Göttingen, 37077 Goettingen, Germany
| | - Stephanie Werner
- Department of Plant Biochemistry, Albrecht-von-Haller-Institute for Plant Sciences, Georg-August-University Göttingen, 37077 Goettingen, Germany
- Department of Cellular Biochemistry, Institute for Biochemistry, Martin-Luther-University Halle-Wittenberg, 06120 Halle (Saale), Germany
| | | | - Jennifer Lerche
- Department of Plant Biochemistry, Albrecht-von-Haller-Institute for Plant Sciences, Georg-August-University Göttingen, 37077 Goettingen, Germany
- Department of Cellular Biochemistry, Institute for Biochemistry, Martin-Luther-University Halle-Wittenberg, 06120 Halle (Saale), Germany
| | - Mónica Meijón
- Gregor-Mendel-Institute for Molecular Plant Biology, 1030 Vienna, Austria
| | - Irene Stenzel
- Department of Plant Biochemistry, Albrecht-von-Haller-Institute for Plant Sciences, Georg-August-University Göttingen, 37077 Goettingen, Germany
- Department of Cellular Biochemistry, Institute for Biochemistry, Martin-Luther-University Halle-Wittenberg, 06120 Halle (Saale), Germany
| | - Christian Löfke
- Department of Plant Cell Biology, Albrecht-von-Haller-Institute for Plant Sciences, Schwann-Schleiden Centre, Georg-August-University Göttingen, 37077 Goettingen, Germany
| | - Theresa Wiessner
- Department of Cell and Metabolic Biology, Leibniz Institute of Plant Biochemistry, 06120 Halle (Saale), Germany
| | - Yang Ju Im
- Department of Plant Biology, North Carolina State University, Raleigh, North Carolina 27695
| | - Imara Y. Perera
- Department of Plant Biology, North Carolina State University, Raleigh, North Carolina 27695
| | - Tim Iven
- Department of Plant Biochemistry, Albrecht-von-Haller-Institute for Plant Sciences, Georg-August-University Göttingen, 37077 Goettingen, Germany
| | - Ivo Feussner
- Department of Plant Biochemistry, Albrecht-von-Haller-Institute for Plant Sciences, Georg-August-University Göttingen, 37077 Goettingen, Germany
| | - Wolfgang Busch
- Gregor-Mendel-Institute for Molecular Plant Biology, 1030 Vienna, Austria
| | - Wendy F. Boss
- Department of Plant Biology, North Carolina State University, Raleigh, North Carolina 27695
| | - Thomas Teichmann
- Department of Plant Cell Biology, Albrecht-von-Haller-Institute for Plant Sciences, Schwann-Schleiden Centre, Georg-August-University Göttingen, 37077 Goettingen, Germany
| | - Bettina Hause
- Department of Cell and Metabolic Biology, Leibniz Institute of Plant Biochemistry, 06120 Halle (Saale), Germany
| | - Staffan Persson
- Max-Planck-Institute for Molecular Plant Physiology, D-14476 Potsdam-Golm, Germany
| | - Ingo Heilmann
- Department of Plant Biochemistry, Albrecht-von-Haller-Institute for Plant Sciences, Georg-August-University Göttingen, 37077 Goettingen, Germany
- Department of Cellular Biochemistry, Institute for Biochemistry, Martin-Luther-University Halle-Wittenberg, 06120 Halle (Saale), Germany
- Address correspondence to
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25
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Huang SJ, Chang CL, Wang PH, Tsai MC, Hsu PH, Chang IF. A type III ACC synthase, ACS7, is involved in root gravitropism in Arabidopsis thaliana. JOURNAL OF EXPERIMENTAL BOTANY 2013; 64:4343-60. [PMID: 23943848 PMCID: PMC3808318 DOI: 10.1093/jxb/ert241] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Ethylene is an important plant hormone that regulates developmental processes in plants. The ethylene biosynthesis pathway is a highly regulated process at both the transcriptional and post-translational level. The transcriptional regulation of these ethylene biosynthesis genes is well known. However, post-translational modifications of the key ethylene biosynthesis enzyme 1-aminocyclopropane-1-carboxylate (ACC) synthase (ACS) are little understood. In vitro kinase assays were conducted on the type III ACS, AtACS7, fusion protein and peptides to determine whether the AtACS7 protein can be phosphorylated by calcium-dependent protein kinase (CDPK). AtACS7 was phosphorylated at Ser216, Thr296, and Ser299 by AtCDPK16 in vitro. To investigate further the function of the ACS7 gene in Arabidopsis, an acs7-1 loss-of-function mutant was isolated. The acs7-1 mutant exhibited less sensitivity to the inhibition of root gravitropism by treatment with the calcium chelator ethylene glycol tetraacetic acid (EGTA). Seedlings were treated with gradient concentrations of ACC. The results showed that a certain concentration of ethylene enhanced the gravity response. Moreover, the acs7-1 mutant was less sensitive to inhibition of the gravity response by treatment with the auxin polar transport inhibitor 1-naphthylphthalamic acid, but exogenous ACC application recovered root gravitropism. Altogether, the results indicate that AtACS7 is involved in root gravitropism in a calcium-dependent manner in Arabidopsis.
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Affiliation(s)
- Shih-Jhe Huang
- Institute of Plant Biology, National Taiwan University, Taipei, Taiwan
| | - Chia-Lun Chang
- Institute of Plant Biology, National Taiwan University, Taipei, Taiwan
| | - Po-Hsun Wang
- Institute of Plant Biology, National Taiwan University, Taipei, Taiwan
| | - Min-Chieh Tsai
- Institute of Plant Biology, National Taiwan University, Taipei, Taiwan
| | - Pang-Hung Hsu
- Institute of Bioscience and Biotechnology, National Taiwan Ocean University, Keelung, Taiwan
| | - Ing-Feng Chang
- Institute of Plant Biology, National Taiwan University, Taipei, Taiwan
- Department of Life Science, National Taiwan University, Taipei, Taiwan
- * To whom correspondence should be addressed. E-mail:
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Toyota M, Furuichi T, Sokabe M, Tatsumi H. Analyses of a gravistimulation-specific Ca2+ signature in Arabidopsis using parabolic flights. PLANT PHYSIOLOGY 2013; 163:543-54. [PMID: 23835410 PMCID: PMC3793036 DOI: 10.1104/pp.113.223313] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Gravity is a critical environmental factor affecting the morphology and functions of organisms on the Earth. Plants sense changes in the gravity vector (gravistimulation) and regulate their growth direction accordingly. In Arabidopsis (Arabidopsis thaliana) seedlings, gravistimulation, achieved by rotating the specimens under the ambient 1g of the Earth, is known to induce a biphasic (transient and sustained) increase in cytoplasmic calcium concentration ([Ca(2+)]c). However, the [Ca(2+)]c increase genuinely caused by gravistimulation has not been identified because gravistimulation is generally accompanied by rotation of specimens on the ground (1g), adding an additional mechanical signal to the treatment. Here, we demonstrate a gravistimulation-specific Ca(2+) response in Arabidopsis seedlings by separating rotation from gravistimulation by using the microgravity (less than 10(-4)g) conditions provided by parabolic flights. Gravistimulation without rotating the specimen caused a sustained [Ca(2+)]c increase, which corresponds closely to the second sustained [Ca(2+)]c increase observed in ground experiments. The [Ca(2+)]c increases were analyzed under a variety of gravity intensities (e.g. 0.5g, 1.5g, or 2g) combined with rapid switching between hypergravity and microgravity, demonstrating that Arabidopsis seedlings possess a very rapid gravity-sensing mechanism linearly transducing a wide range of gravitational changes (0.5g-2g) into Ca(2+) signals on a subsecond time scale.
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Hu L, Mei Z, Zang A, Chen H, Dou X, Jin J, Cai W. Microarray analyses and comparisons of upper or lower flanks of rice shoot base preceding gravitropic bending. PLoS One 2013; 8:e74646. [PMID: 24040303 PMCID: PMC3764065 DOI: 10.1371/journal.pone.0074646] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2011] [Accepted: 08/06/2013] [Indexed: 11/26/2022] Open
Abstract
Gravitropism is a complex process involving a series of physiological pathways. Despite ongoing research, gravitropism sensing and response mechanisms are not well understood. To identify the key transcripts and corresponding pathways in gravitropism, a whole-genome microarray approach was used to analyze transcript abundance in the shoot base of rice (Oryza sativa sp. japonica) at 0.5 h and 6 h after gravistimulation by horizontal reorientation. Between upper and lower flanks of the shoot base, 167 transcripts at 0.5 h and 1202 transcripts at 6 h were discovered to be significantly different in abundance by 2-fold. Among these transcripts, 48 were found to be changed both at 0.5 h and 6 h, while 119 transcripts were only changed at 0.5 h and 1154 transcripts were changed at 6 h in association with gravitropism. MapMan and PageMan analyses were used to identify transcripts significantly changed in abundance. The asymmetric regulation of transcripts related to phytohormones, signaling, RNA transcription, metabolism and cell wall-related categories between upper and lower flanks were demonstrated. Potential roles of the identified transcripts in gravitropism are discussed. Our results suggest that the induction of asymmetrical transcription, likely as a consequence of gravitropic reorientation, precedes gravitropic bending in the rice shoot base.
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Affiliation(s)
- Liwei Hu
- Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Graduate School of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Zhiling Mei
- Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Graduate School of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Aiping Zang
- Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Graduate School of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Haiying Chen
- Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Graduate School of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Xianying Dou
- Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Graduate School of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Jing Jin
- Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Graduate School of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Weiming Cai
- Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Graduate School of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai, China
- * E-mail:
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Djafi N, Vergnolle C, Cantrel C, Wietrzyñski W, Delage E, Cochet F, Puyaubert J, Soubigou-Taconnat L, Gey D, Collin S, Balzergue S, Zachowski A, Ruelland E. The Arabidopsis DREB2 genetic pathway is constitutively repressed by basal phosphoinositide-dependent phospholipase C coupled to diacylglycerol kinase. FRONTIERS IN PLANT SCIENCE 2013; 4:307. [PMID: 23964284 PMCID: PMC3737466 DOI: 10.3389/fpls.2013.00307] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/12/2013] [Accepted: 07/22/2013] [Indexed: 05/02/2023]
Abstract
Phosphoinositide-dependent phospholipases C (PI-PLCs) are activated in response to various stimuli. They utilize substrates provided by type III-Phosphatidylinositol-4 kinases (PI4KIII) to produce inositol triphosphate and diacylglycerol (DAG) that is phosphorylated into phosphatidic acid (PA) by DAG-kinases (DGKs). The roles of PI4KIIIs, PI-PLCs, and DGKs in basal signaling are poorly understood. We investigated the control of gene expression by basal PI-PLC pathway in Arabidopsis thaliana suspension cells. A transcriptome-wide analysis allowed the identification of genes whose expression was altered by edelfosine, 30 μM wortmannin, or R59022, inhibitors of PI-PLCs, PI4KIIIs, and DGKs, respectively. We found that a gene responsive to one of these molecules is more likely to be similarly regulated by the other two inhibitors. The common action of these agents is to inhibit PA formation, showing that basal PI-PLCs act, in part, on gene expression through their coupling to DGKs. Amongst the genes up-regulated in presence of the inhibitors, were some DREB2 genes, in suspension cells and in seedlings. The DREB2 genes encode transcription factors with major roles in responses to environmental stresses, including dehydration. They bind to C-repeat motifs, known as Drought-Responsive Elements that are indeed enriched in the promoters of genes up-regulated by PI-PLC pathway inhibitors. PA can also be produced by phospholipases D (PLDs). We show that the DREB2 genes that are up-regulated by PI-PLC inhibitors are positively or negatively regulated, or indifferent, to PLD basal activity. Our data show that the DREB2 genetic pathway is constitutively repressed in resting conditions and that DGK coupled to PI-PLC is active in this process, in suspension cells and seedlings. We discuss how this basal negative regulation of DREB2 genes is compatible with their stress-triggered positive regulation.
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Affiliation(s)
- Nabila Djafi
- Physiologie Cellulaire et Moléculaire des Plantes, CNRS EAC7180Paris, France
- Physiologie Cellulaire et Moléculaire des Plantes, UPMC-Univ Paris06 UR5Paris, France
| | - Chantal Vergnolle
- Physiologie Cellulaire et Moléculaire des Plantes, CNRS EAC7180Paris, France
- Physiologie Cellulaire et Moléculaire des Plantes, UPMC-Univ Paris06 UR5Paris, France
| | - Catherine Cantrel
- Physiologie Cellulaire et Moléculaire des Plantes, CNRS EAC7180Paris, France
- Physiologie Cellulaire et Moléculaire des Plantes, UPMC-Univ Paris06 UR5Paris, France
| | | | - Elise Delage
- Physiologie Cellulaire et Moléculaire des Plantes, CNRS EAC7180Paris, France
- Physiologie Cellulaire et Moléculaire des Plantes, UPMC-Univ Paris06 UR5Paris, France
| | - Françoise Cochet
- Physiologie Cellulaire et Moléculaire des Plantes, CNRS EAC7180Paris, France
- Physiologie Cellulaire et Moléculaire des Plantes, UPMC-Univ Paris06 UR5Paris, France
| | - Juliette Puyaubert
- Physiologie Cellulaire et Moléculaire des Plantes, CNRS EAC7180Paris, France
- Physiologie Cellulaire et Moléculaire des Plantes, UPMC-Univ Paris06 UR5Paris, France
| | - Ludivine Soubigou-Taconnat
- Unité de Recherche en Biologie Végétale, UMR INRA 1165, Université d'Evry Val d'Essonne, ERL CNRS 8196Evry Cedex, France
| | - Delphine Gey
- Unité de Recherche en Biologie Végétale, UMR INRA 1165, Université d'Evry Val d'Essonne, ERL CNRS 8196Evry Cedex, France
| | - Sylvie Collin
- Physiologie Cellulaire et Moléculaire des Plantes, CNRS EAC7180Paris, France
- Physiologie Cellulaire et Moléculaire des Plantes, UPMC-Univ Paris06 UR5Paris, France
| | - Sandrine Balzergue
- Unité de Recherche en Biologie Végétale, UMR INRA 1165, Université d'Evry Val d'Essonne, ERL CNRS 8196Evry Cedex, France
| | - Alain Zachowski
- Physiologie Cellulaire et Moléculaire des Plantes, CNRS EAC7180Paris, France
- Physiologie Cellulaire et Moléculaire des Plantes, UPMC-Univ Paris06 UR5Paris, France
| | - Eric Ruelland
- Physiologie Cellulaire et Moléculaire des Plantes, CNRS EAC7180Paris, France
- Physiologie Cellulaire et Moléculaire des Plantes, UPMC-Univ Paris06 UR5Paris, France
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Singh A, Kanwar P, Pandey A, Tyagi AK, Sopory SK, Kapoor S, Pandey GK. Comprehensive genomic analysis and expression profiling of phospholipase C gene family during abiotic stresses and development in rice. PLoS One 2013; 8:e62494. [PMID: 23638098 PMCID: PMC3640072 DOI: 10.1371/journal.pone.0062494] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2012] [Accepted: 03/22/2013] [Indexed: 12/27/2022] Open
Abstract
BACKGROUND Phospholipase C (PLC) is one of the major lipid hydrolysing enzymes, implicated in lipid mediated signaling. PLCs have been found to play a significant role in abiotic stress triggered signaling and developmental processes in various plant species. Genome wide identification and expression analysis have been carried out for this gene family in Arabidopsis, yet not much has been accomplished in crop plant rice. METHODOLOGY/PRINCIPAL FINDINGS An exhaustive in-silico exploration of rice genome using various online databases and tools resulted in the identification of nine PLC encoding genes. Based on sequence, motif and phylogenetic analysis rice PLC gene family could be divided into phosphatidylinositol-specific PLCs (PI-PLCs) and phosphatidylcholine- PLCs (PC-PLC or NPC) classes with four and five members, respectively. A comparative analysis revealed that PLCs are conserved in Arabidopsis (dicots) and rice (monocot) at gene structure and protein level but they might have evolved through a separate evolutionary path. Transcript profiling using gene chip microarray and quantitative RT-PCR showed that most of the PLC members expressed significantly and differentially under abiotic stresses (salt, cold and drought) and during various developmental stages with condition/stage specific and overlapping expression. This finding suggested an important role of different rice PLC members in abiotic stress triggered signaling and plant development, which was also supported by the presence of relevant cis-regulatory elements in their promoters. Sub-cellular localization of few selected PLC members in Nicotiana benthamiana and onion epidermal cells has provided a clue about their site of action and functional behaviour. CONCLUSION/SIGNIFICANCE The genome wide identification, structural and expression analysis and knowledge of sub-cellular localization of PLC gene family envisage the functional characterization of these genes in crop plants in near future.
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Affiliation(s)
- Amarjeet Singh
- Department of Plant Molecular Biology, University of Delhi South Campus, New Delhi, India
| | - Poonam Kanwar
- Department of Plant Molecular Biology, University of Delhi South Campus, New Delhi, India
| | - Amita Pandey
- Department of Plant Molecular Biology, University of Delhi South Campus, New Delhi, India
| | - Akhilesh K. Tyagi
- Department of Plant Molecular Biology, University of Delhi South Campus, New Delhi, India
- National Institute of Plant Genome Research, New Delhi, India
| | | | - Sanjay Kapoor
- Department of Plant Molecular Biology, University of Delhi South Campus, New Delhi, India
| | - Girdhar K. Pandey
- Department of Plant Molecular Biology, University of Delhi South Campus, New Delhi, India
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Schenck CA, Nadella V, Clay SL, Lindner J, Abrams Z, Wyatt SE. A proteomics approach identifies novel proteins involved in gravitropic signal transduction. AMERICAN JOURNAL OF BOTANY 2013; 100:194-202. [PMID: 23281391 DOI: 10.3732/ajb.1200339] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
PREMISE Plant organs use gravity as a guide to direct their growth. And although gravitropism has been studied since the time of Darwin, the mechanisms of signal transduction, those that connect the biophysical stimulus perception and the biochemical events of the response, are still not understood. METHODS A quantitative proteomics approach was used to identify key proteins during the early events of gravitropism. Plants were subjected to a gravity persistent signal (GPS) treatment, and proteins were extracted from the inflorescence stem at early time points after stimulation. Proteins were labeled with isobaric tags for relative and absolute quantification (iTRAQ) reagents. Proteins were identified and quantified as a single step using tandem mass-spectrometry (MS/MS). For two of the proteins identified, mutants with T-DNA inserts in the corresponding genes were evaluated for gravitropic phenotypes. KEY RESULTS A total of 82 proteins showed significant differential quantification between treatment and controls. Proteins were categorized into functional groups based on gene ontology terms and filtered using groups thought to be involved in the signaling events of gravitropism. For two of the proteins selected, GSTF9 and HSP81-2, knockout mutations resulted in defects in root skewing, waving, and curvature as well as in the GPS response of inflorescence stems. CONCLUSION Combining a proteomics approach with the GPS response, 82 novel proteins were identified to be involved in the early events of gravitropic signal transduction. As early as 2 and 4 min after a gravistimulation, significant changes occur in protein abundance. The approach was validated through the analysis of mutants exhibiting altered gravitropic responses.
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Affiliation(s)
- Craig A Schenck
- Department of Environmental and Plant Biology, Ohio University, Athens, Ohio 45701, USA
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31
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Clore AM. Cereal grass pulvini: agronomically significant models for studying gravitropism signaling and tissue polarity. AMERICAN JOURNAL OF BOTANY 2013; 100:101-10. [PMID: 23125431 DOI: 10.3732/ajb.1200286] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Cereal grass pulvini have emerged as model systems that are not only valuable for the study of gravitropism, but are also of agricultural and economic significance. The pulvini are regions of tissue that are apical to each node and collectively return a reoriented stem to a more vertical position. They have proven to be useful for the study of gravisensing and response and are also providing clues about the establishment of polarity across tissues. This review will first highlight the agronomic significance of these stem regions and their benefits for use as model systems and provide a brief historical overview. A detailed discussion of the literature focusing on cell signaling and early changes in gene expression will follow, culminating in a temporal framework outlining events in the signaling and early growth phases of gravitropism in this tissue. Changes in cell wall composition and gene expression that occur well into the growth phase will be touched upon briefly. Finally, some ongoing research involving both maize and wheat pulvini will be introduced along with prospects for future investigations.
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Affiliation(s)
- Amy M Clore
- Division of Natural Sciences, New College of Florida, 5800 Bay Shore Road, Sarasota, Florida 34243 USA.
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Smith CM, Desai M, Land ES, Perera IY. A role for lipid-mediated signaling in plant gravitropism. AMERICAN JOURNAL OF BOTANY 2013; 100:153-60. [PMID: 23258369 DOI: 10.3732/ajb.1200355] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Gravitropism is a universal plant response. It is initiated by the sensing of the primary signal (mass or pressure), which is then converted into chemical signals that are transduced and propagated in a precise spatial and temporal fashion, resulting in a differential growth response. Our thesis is that membrane lipids and lipid-mediated signaling pathways play critical roles in the initial signaling and in the establishment of polarity. In this review, we highlight results from recent literature and discuss the major questions that remain unanswered.
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Affiliation(s)
- Caroline M Smith
- Department of Plant Biology, Campus Box 7612, North Carolina State University, Raleigh, North Carolina 27695, USA
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Heilmann I, Perera IY. Measurement of inositol (1,4,5) trisphosphate in plant tissues by a competitive receptor binding assay. Methods Mol Biol 2013; 1009:33-41. [PMID: 23681521 DOI: 10.1007/978-1-62703-401-2_4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
The phosphoinositide signaling pathway is important for plant responses to many different stresses. As part of the responses to a stimulus, InsP3 levels may increase rapidly and transiently. The receptor binding assay for InsP3 described here is easy to use and an ideal method to monitor and compare InsP3 levels in multiple samples from large scale experiments. The method is based on competitive binding of InsP3 to the mammalian brain InsP3 specific receptor protein. This chapter describes a protocol for extracting and neutralizing plant samples and performing the receptor binding assay (using a commercially available kit). The protocol described has been used effectively to monitor InsP3 levels in plant tissues of different origin and in response to different stresses.
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Affiliation(s)
- Ingo Heilmann
- Department of Cellular Biochemistry, Institute for Biochemistry and Biotechnology, Martin-Luther-University Halle-Wittenberg, Halle, Germany
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Baldwin KL, Strohm AK, Masson PH. Gravity sensing and signal transduction in vascular plant primary roots. AMERICAN JOURNAL OF BOTANY 2013; 100:126-42. [PMID: 23048015 DOI: 10.3732/ajb.1200318] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
During gravitropism, the potential energy of gravity is converted into a biochemical signal. How this transfer occurs remains one of the most exciting mysteries in plant cell biology. New experiments are filling in pieces of the puzzle. In this review, we introduce gravitropism and give an overview of what we know about gravity sensing in roots of vascular plants, with special highlight on recent papers. When plant roots are reoriented sideways, amyloplast resedimentation in the columella cells is a key initial step in gravity sensing. This process somehow leads to cytoplasmic alkalinization of these cells followed by relocalization of auxin efflux carriers (PINs). This changes auxin flow throughout the root, generating a lateral gradient of auxin across the cap that upon transmission to the elongation zone leads to differential cell elongation and gravibending. We will present the evidence for and against the following players having a role in transferring the signal from the amyloplast sedimentation into the auxin signaling cascade: mechanosensitive ion channels, actin, calcium ions, inositol trisphosphate, receptors/ligands, ARG1/ARL2, spermine, and the TOC complex. We also outline auxin transport and signaling during gravitropism.
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Affiliation(s)
- Katherine L Baldwin
- Laboratory of Genetics and Program of Cellular and Molecular Biology, University of Wisconsin-Madison, 425G Henry Mall, Madison, Wisconsin 53706, USA
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Strohm AK, Baldwin KL, Masson PH. Multiple roles for membrane-associated protein trafficking and signaling in gravitropism. FRONTIERS IN PLANT SCIENCE 2012; 3:274. [PMID: 23248632 PMCID: PMC3518769 DOI: 10.3389/fpls.2012.00274] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2012] [Accepted: 11/21/2012] [Indexed: 05/07/2023]
Abstract
Gravitropism is a process that allows plant organs to guide their growth relative to the gravity vector. It requires them to sense changes in their orientation and generate a biochemical signal that they transmit to the tissues that drive organ curvature. Trafficking between the plasma membrane and endosomal compartments is important for all of these phases of the gravitropic response. The sedimentation of starch-filled organelles called amyloplasts plays a key role in sensing reorientation, and vacuolar integrity is required for amyloplast sedimentation in shoots. Other proteins associated with the vesicle trafficking pathway contribute to early gravity signal transduction independently of amyloplast sedimentation in both roots and hypocotyls. Phosphatidylinositol signaling, which starts at the plasma membrane and later affects the localization of auxin efflux facilitators, is a likely second messenger in the signal transduction phase of gravitropism. Finally, membrane-localized auxin influx and efflux facilitators contribute to a differential auxin gradient across the gravistimulated organs, which directs root curvature.
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Affiliation(s)
- Allison K. Strohm
- Laboratory of Genetics, University of Wisconsin-MadisonMadison, WI, USA
- Graduate Program in Cellular and Molecular Biology, University of Wisconsin-MadisonMadison, WI, USA
| | - Katherine L. Baldwin
- Laboratory of Genetics, University of Wisconsin-MadisonMadison, WI, USA
- Graduate Program in Cellular and Molecular Biology, University of Wisconsin-MadisonMadison, WI, USA
| | - Patrick H. Masson
- Laboratory of Genetics, University of Wisconsin-MadisonMadison, WI, USA
- *Correspondence: Patrick H. Masson, Laboratory of Genetics, University of Wisconsin-Madison, 425G Henry Mall, Madison, WI 53706, USA. e-mail:
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Strohm AK, Baldwin KL, Masson PH. Molecular mechanisms of root gravity sensing and signal transduction. WILEY INTERDISCIPLINARY REVIEWS-DEVELOPMENTAL BIOLOGY 2011; 1:276-85. [PMID: 23801441 DOI: 10.1002/wdev.14] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Plants use gravity as a guide to direct their roots down into the soil to anchor themselves and to find resources needed for growth and development. In higher plants, the columella cells of the root tip form the primary site of gravity sensing, and in these cells the sedimentation of dense, starch-filled plastids (amyloplasts) triggers gravity signal transduction. This generates an auxin gradient across the root cap that is transmitted to the elongation zone where it promotes differential cell elongation, allowing the root to direct itself downward. It is still not well understood how amyloplast sedimentation leads to auxin redistribution. Models have been proposed to explain how mechanosensitive ion channels or ligand-receptor interactions could connect these events. Although their roles are still unclear, possible second messengers in this process include protons, Ca(2+), and inositol 1,4,5-triphosphate. Upon gravistimulation, the auxin efflux facilitators PIN3 and PIN7 relocalize to the lower side of the columella cells and mediate auxin redistribution. However, evidence for an auxin-independent secondary mechanism of gravity sensing and signal transduction suggests that this physiological process is quite complex. Furthermore, plants must integrate a variety of environmental cues, resulting in multifaceted relationships between gravitropism and other directional growth responses such as hydro-, photo-, and thigmotropism.
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Abstract
The simple polyol, myo-inositol, is used as a building block of a cellular language that plays various roles in signal transduction. This review describes the terminology used to denote myo-inositol-containing molecules, with an emphasis on how phosphate and fatty acids are added to create second messengers used in signaling. Work in model systems has delineated the genes and enzymes required for synthesis and metabolism of many myo-inositol-containing molecules, with genetic mutants and measurement of second messengers playing key roles in developing our understanding. There is increasing evidence that molecules such as myo- inositol(1,4,5)trisphosphate and phosphatidylinositol(4,5)bisphosphate are synthesized in response to various signals plants encounter. In particular, the controversial role of myo-inositol(1,4,5)trisphosphate is addressed, accompanied by a discussion of the multiple enzymes that act to regulate this molecule. We are also beginning to understand new connections of myo-inositol signaling in plants. These recent discoveries include the novel roles of inositol phosphates in binding to plant hormone receptors and that of phosphatidylinositol(3)phosphate binding to pathogen effectors.
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Affiliation(s)
- Glenda E Gillaspy
- Department of Biochemistry, Virginia Tech, Blacksburg, VA 24061, USA
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Tan C, Wang H, Zhang Y, Qi B, Xu G, Zheng H. A proteomic approach to analyzing responses of Arabidopsis thaliana root cells to different gravitational conditions using an agravitropic mutant, pin2 and its wild type. Proteome Sci 2011; 9:72. [PMID: 22085406 PMCID: PMC3228730 DOI: 10.1186/1477-5956-9-72] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2011] [Accepted: 11/16/2011] [Indexed: 12/18/2022] Open
Abstract
Background Root gravitropsim has been proposed to require the coordinated, redistribution of the plant signaling molecule auxin within the root meristem, but the underlying molecular mechanisms are still unknown. PIN proteins are membrane transporters that mediate the efflux of auxin from cells. The PIN2 is important for the basipetal transport of auxin in roots and plays a critical role in the transmission of gravity signals perceived in the root cap to the root elongation zone. The loss of function pin2 mutant exhibits a gravity-insensitive root growth phenotype. By comparing the proteomes of wild type and the pin2 mutant root tips under different gravitational conditions, we hope to identify proteins involved in the gravity-related signal transduction. Results To identify novel proteins involved in the gravity signal transduction pathway we have carried out a comparative proteomic analysis of Arabidopsis pin2 mutant and wild type (WT) roots subjected to different gravitational conditions. These conditions included horizontal (H) and vertical (V) clinorotation, hypergravity (G) and the stationary control (S). Analysis of silver-stained two-dimensional SDS-PAGE gels revealed 28 protein spots that showed significant expression changes in altered gravity (H or G) compared to control roots (V and S). Whereas the majority of these proteins exhibited similar expression patterns in WT and pin2 roots, a significant number displayed different patterns of response between WT and pin2 roots. The latter group included 11 protein spots in the H samples and two protein spots in the G samples that exhibited an altered expression exclusively in WT but not in pin2 roots. One of these proteins was identified as annexin2, which was induced in the root cap columella cells under altered gravitational conditions. Conclusions The most interesting observation in this study is that distinctly different patterns of protein expression were found in WT and pin2 mutant roots subjected to altered gravity conditions. The data also demonstrate that PIN2 mutation not only affects the basipetal transport of auxin to the elongation zone, but also results in an altered expression of proteins in the root columella.
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Affiliation(s)
- Chao Tan
- Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 300 Fenglin Road, Shanghai 200032, China.
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Paul AL, Manak MS, Mayfield JD, Reyes MF, Gurley WB, Ferl RJ. Parabolic flight induces changes in gene expression patterns in Arabidopsis thaliana. ASTROBIOLOGY 2011; 11:743-58. [PMID: 21970703 DOI: 10.1089/ast.2011.0659] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Our primary objective was to evaluate gene expression changes in Arabidopsis thaliana in response to parabolic flight as part of a comprehensive approach to the molecular biology of spaceflight-related adaptations. In addition, we wished to establish parabolic flight as a tractable operations platform for molecular biology studies. In a succession of experiments on NASA's KC-135 and C-9 parabolic aircraft, Arabidopsis plants were presented with replicated exposure to parabolic flight. Transcriptome profiling revealed that parabolic flight caused changes in gene expression patterns that stood the statistical tests of replication on three different flight days. The earliest response, after 20 parabolas, was characterized by a prominence of genes associated with signal transduction. After 40 parabolas, this prominence was largely replaced by genes associated with biotic and abiotic stimuli and stress. Among these responses, three metabolic processes stand out in particular: the induction of auxin metabolism and signaling, the differential expression of genes associated with calcium-mediated signaling, and the repression of genes associated with disease resistance and cell wall biochemistry. Many, but not all, of these responses are known to be involved in gravity sensing in plants. Changes in auxin-related gene expression were also recorded by reporter genes tuned to auxin signal pathways. These data demonstrate that the parabolic flight environment is appropriate for molecular biology research involving the transition to microgravity, in that with replication, proper controls, and analyses, gene expression changes can be observed in the time frames of typical parabolic flight experiments.
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Affiliation(s)
- Anna-Lisa Paul
- Horticultural Sciences and Genetics Institute, University of Florida, Gainesville, USA
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Sun J, Liu X, Pan Y. The physical interaction between LdPLCs and Arabidopsis G beta in a yeast two-hybrid system. ACTA ACUST UNITED AC 2011. [DOI: 10.1007/s11703-011-1063-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Salinas-Mondragon RE, Kajla JD, Perera IY, Brown CS, Sederoff HW. Role of inositol 1,4,5-triphosphate signalling in gravitropic and phototropic gene expression. PLANT, CELL & ENVIRONMENT 2010; 33:2041-55. [PMID: 20584147 DOI: 10.1111/j.1365-3040.2010.02204.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Plants sense light and gravity to orient their direction of growth. One common component in the early events of both phototropic and gravitropic signal transduction is activation of phospholipase C (PLC), which leads to an increase in inositol 1,4,5-triphosphate (InsP(3)) levels. The InsP(3) signal is terminated by hydrolysis of InsP(3) through inositolpolyphosphate-5-phosphatases (InsP 5-ptases). Arabidopsis plants expressing a heterologous InsP 5-ptase have low basal InsP(3) levels and exhibit reduced gravitropic and phototropic bending. Downstream effects of InsP(3)-mediated signalling are not understood. We used comparative transcript profiling to characterize gene expression changes in gravity- or light-stimulated Arabidopsis root apices that were manipulated in their InsP(3) metabolism either through inhibition of PLC activity or expression of InsP 5-ptase. We identified InsP(3)-dependent and InsP(3)-independent co-regulated gene sets in response to gravity or light stimulation. Inhibition of PLC activity in wild-type plants caused similar changes in transcript abundance in response to gravitropic and phototropic stimulation as in the transgenic lines. Therefore, we conclude that changes in gene expression in response to gravitropic and phototropic stimulation are mediated by two signal transduction pathways that vary in their dependence on changes in InsP(3).
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Andreeva Z, Barton D, Armour WJ, Li MY, Liao LF, McKellar HL, Pethybridge KA, Marc J. Inhibition of phospholipase C disrupts cytoskeletal organization and gravitropic growth in Arabidopsis roots. PLANTA 2010; 232:1263-79. [PMID: 20803215 DOI: 10.1007/s00425-010-1256-0] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2010] [Accepted: 08/15/2010] [Indexed: 05/11/2023]
Abstract
The phospholipase protein superfamily plays an important role in hormonal signalling and cellular responses to environmental stimuli. There is also growing evidence for interactions between phospholipases and the cytoskeleton. In this report we used a pharmacological approach to investigate whether inhibiting a member of the phospholipase superfamily, phospholipase C (PLC), affects microtubules and actin microfilaments as well as root growth and morphology of Arabidopsis thaliana seedlings. Inhibiting PLC activity using the aminosteroid U73122 significantly inhibited root elongation and disrupted root morphology in a concentration-dependent manner, with the response being saturated at 5 μM, whereas the inactive analogue U73343 was ineffective. The primary root appeared to lose growth directionality accompanied by root waving and formation of curls. Immunolabelling of roots exposed to increasingly higher U73122 concentrations revealed that the normal transverse arrays of cortical microtubules in the elongation zone became progressively more disorganized or depolymerized, with the disorganization appearing within 1 h of incubation. Likewise, actin microfilament arrays also were disrupted. Inhibiting PLC using an alternative inhibitor, neomycin, caused similar disruptions to both cytoskeletal organization and root morphology. In seedlings gravistimulated by rotating the culture plates by 90°, both U73122 and neomycin disrupted the normal gravitropic growth of roots and etiolated hypocotyls. The effects of PLC inhibitors are therefore consistent with the notion that, as with phospholipases A and D, PLC likewise interacts with the cytoskeleton, alters growth morphology, and is involved in gravitropism.
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Affiliation(s)
- Zornitza Andreeva
- School of Biological Sciences, University of Sydney, Sydney, NSW, Australia
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The Emerging Roles of Phospholipase C in Plant Growth and Development. LIPID SIGNALING IN PLANTS 2010. [DOI: 10.1007/978-3-642-03873-0_2] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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Abstract
Plants can reorient their growth direction by sensing organ tilt relative to the direction of gravity. With respect to gravity sensing in gravitropism, the classic starch statolith hypothesis, i.e., that starch-accumulating amyloplast movement along the gravity vector within gravity-sensing cells (statocytes) is the probable trigger of subsequent intracellular signaling, is widely accepted. Several lines of experimental evidence have demonstrated that starch is important but not essential for gravity sensing and have suggested that it is reasonable to regard plastids (containers of starch) as statoliths. Although the word statolith means sedimented stone, actual amyloplasts are not static but instead possess dynamic movement. Recent studies combining genetic and cell biological approaches, using Arabidopsis thaliana, have demonstrated that amyloplast movement is an intricate process involving vacuolar membrane structures and the actin cytoskeleton. This review covers current knowledge regarding gravity sensing, particularly gravity susception, and the factors modulating the function of amyloplasts for sensing the directional change of gravity. Specific emphasis is made on the remarkable differences in the cytological properties, developmental origins, tissue locations, and response of statocytes between root and shoot systems. Such an approach reveals a common theme in directional gravity-sensing mechanisms in these two disparate organs.
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Affiliation(s)
- Miyo Terao Morita
- Graduate School of Biological Sciences, Nara Institute of Science and Technology, Nara, Japan.
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Stanga J, Baldwin K, Masson PH. Joining forces: the interface of gravitropism and plastid protein import. PLANT SIGNALING & BEHAVIOR 2009; 4:933-41. [PMID: 19826232 PMCID: PMC2801356 DOI: 10.4161/psb.4.10.9470] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
In flowering plants, gravity perception appears to involve the sedimentation of starch-filled plastids, called amyloplasts, within specialized cells (the statocytes) of shoots (endodermal cells) and roots (columella cells). Unfortunately, how the physical information derived from amyloplast sedimentation is converted into a biochemical signal that promotes organ gravitropic curvature remains largely unknown. Recent results suggest an involvement of the Translocon of the Outer Envelope of (Chloro)plastids (TOC) in early phases of gravity signal transduction within the statocytes. This review summarizes our current knowledge of the molecular mechanisms that govern gravity signal transduction in flowering plants and summarizes models that attempt to explain the contribution of TOC proteins in this important behavioral plant growth response to its mechanical environment.
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Affiliation(s)
- John Stanga
- Laboratory of Genetics, University of Wisconsin-Madison, Madison, WI, USA
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The role of Arabidopsis 5PTase13 in root gravitropism through modulation of vesicle trafficking. Cell Res 2009; 19:1191-204. [PMID: 19736566 DOI: 10.1038/cr.2009.105] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Inositol polyphosphate 5-phosphatases (5PTases) are enzymes of phosphatidylinositol metabolism that affect various aspects of plant growth and development. Arabidopsis 5PTase13 regulates auxin homeostasis and hormone-related cotyledon vein development, and here we demonstrate that its knockout mutant 5pt13 has elevated sensitivity to gravistimulation in root gravitropic responses. The altered responses of 5pt13 mutants to 1-N-naphthylphthalamic acid (an auxin transport inhibitor) indicate that 5PTase13 might be involved in the regulation of auxin transport. Indeed, the auxin efflux carrier PIN2 is expressed more broadly under 5PTase13 deficiency, and observations of the internalization of the membrane-selective dye FM4-64 reveal altered vesicle trafficking in 5pt13 mutants. Compared with wild-type, 5pt13 mutant seedlings are less sensitive to the inhibition by brefeldin A of vesicle cycling, seedling growth, and the intracellular cycling of the PIN1 and PIN2 proteins. Further, auxin redistribution upon gravitropic stimulation is stimulated under 5PTase13 deficiency. These results suggest that 5PTase13 may modulate auxin transport by regulating vesicle trafficking and thereby play a role in root gravitropism.
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Cvrcková F, Lipavská H, Zárský V. Plant intelligence: why, why not or where? PLANT SIGNALING & BEHAVIOR 2009; 4:394-9. [PMID: 19816094 PMCID: PMC2676749 DOI: 10.4161/psb.4.5.8276] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2008] [Accepted: 02/24/2009] [Indexed: 05/09/2023]
Abstract
The concept of plant intelligence, as proposed by Anthony Trewavas, has raised considerable discussion. However, plant intelligence remains loosely defined; often it is either perceived as practically synonymous to Darwinian fitness, or reduced to a mere decorative metaphor. A more strict view can be taken, emphasizing necessary prerequisites such as memory and learning, which requires clarifying the definition of memory itself. To qualify as memories, traces of past events have to be not only stored, but also actively accessed. We propose a criterion for eliminating false candidates of possible plant intelligence phenomena in this stricter sense: an "intelligent" behavior must involve a component that can be approximated by a plausible algorithmic model involving recourse to stored information about past states of the individual or its environment. Re-evaluation of previously presented examples of plant intelligence shows that only some of them pass our test.
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Affiliation(s)
- Fatima Cvrcková
- Department of Plant Physiology, Faculty of Sciences, Charles University, Praha, Czech Republic.
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Ma X, Shor O, Diminshtein S, Yu L, Im YJ, Perera I, Lomax A, Boss WF, Moran N. Phosphatidylinositol (4,5)bisphosphate inhibits K+-efflux channel activity in NT1 tobacco cultured cells. PLANT PHYSIOLOGY 2009; 149:1127-40. [PMID: 19052153 PMCID: PMC2633837 DOI: 10.1104/pp.108.129007] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2008] [Accepted: 11/24/2008] [Indexed: 05/18/2023]
Abstract
In the animal world, the regulation of ion channels by phosphoinositides (PIs) has been investigated extensively, demonstrating a wide range of channels controlled by phosphatidylinositol (4,5)bisphosphate (PtdInsP2). To understand PI regulation of plant ion channels, we examined the in planta effect of PtdInsP2 on the K+-efflux channel of tobacco (Nicotiana tabacum), NtORK (outward-rectifying K channel). We applied a patch clamp in the whole-cell configuration (with fixed "cytosolic" Ca2+ concentration and pH) to protoplasts isolated from cultured tobacco cells with genetically manipulated plasma membrane levels of PtdInsP2 and cellular inositol (1,4,5)trisphosphate: "Low PIs" had depressed levels of these PIs, and "High PIs" had elevated levels relative to controls. In all of these cells, K channel activity, reflected in the net, steady-state outward K+ currents (IK), was inversely related to the plasma membrane PtdInsP2 level. Consistent with this, short-term manipulations decreasing PtdInsP2 levels in the High PIs, such as pretreatment with the phytohormone abscisic acid (25 microM) or neutralizing the bath solution from pH 5.6 to pH 7, increased IK (i.e. NtORK activity). Moreover, increasing PtdInsP2 levels in controls or in abscisic acid-treated high-PI cells, using the specific PI-phospholipase C inhibitor U73122 (2.5-4 microM), decreased NtORK activity. In all cases, IK decreases stemmed largely from decreased maximum attainable NtORK channel conductance and partly from shifted voltage dependence of channel gating to more positive potentials, making it more difficult to activate the channels. These results are consistent with NtORK inhibition by the negatively charged PtdInsP2 in the internal plasma membrane leaflet. Such effects are likely to underlie PI signaling in intact plant cells.
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Affiliation(s)
- Xiaohong Ma
- Robert H. Smith Institute for Plant Sciences and Genetics in Agriculture, Robert H. Smith Faculty of Agriculture, Food and Environment, Hebrew University of Jerusalem, Rehovot 76100, Israel
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