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Barr ZK, Werner T, Tilsner J. Heavy Metal-Associated Isoprenylated Plant Proteins (HIPPs) at Plasmodesmata: Exploring the Link between Localization and Function. PLANTS (BASEL, SWITZERLAND) 2023; 12:3015. [PMID: 37631227 PMCID: PMC10459601 DOI: 10.3390/plants12163015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2023] [Revised: 08/09/2023] [Accepted: 08/14/2023] [Indexed: 08/27/2023]
Abstract
Heavy metal-associated isoprenylated plant proteins (HIPPs) are a metallochaperone-like protein family comprising a combination of structural features unique to vascular plants. HIPPs possess both one or two heavy metal-binding domains and an isoprenylation site, facilitating a posttranslational protein lipid modification. Recent work has characterized individual HIPPs across numerous different species and provided evidence for varied functionalities. Interestingly, a significant number of HIPPs have been identified in proteomes of plasmodesmata (PD)-nanochannels mediating symplastic connectivity within plant tissues that play pivotal roles in intercellular communication during plant development as well as responses to biotic and abiotic stress. As characterized functions of many HIPPs are linked to stress responses, plasmodesmal HIPP proteins are potentially interesting candidate components of signaling events at or for the regulation of PD. Here, we review what is known about PD-localized HIPP proteins specifically, and how the structure and function of HIPPs more generally could link to known properties and regulation of PD.
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Affiliation(s)
- Zoe Kathleen Barr
- Biomedical Sciences Research Complex, University of St Andrews, BMS Building, North Haugh, St Andrews, Fife KY16 9ST, UK;
- Cell & Molecular Sciences, The James Hutton Institute, Dundee DD2 5DA, UK
| | - Tomáš Werner
- Department of Biology, University of Graz, Schubertstraße 51, 8010 Graz, Austria
| | - Jens Tilsner
- Biomedical Sciences Research Complex, University of St Andrews, BMS Building, North Haugh, St Andrews, Fife KY16 9ST, UK;
- Cell & Molecular Sciences, The James Hutton Institute, Dundee DD2 5DA, UK
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2
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Riemer E, Pullagurla NJ, Yadav R, Rana P, Jessen HJ, Kamleitner M, Schaaf G, Laha D. Regulation of plant biotic interactions and abiotic stress responses by inositol polyphosphates. FRONTIERS IN PLANT SCIENCE 2022; 13:944515. [PMID: 36035672 PMCID: PMC9403785 DOI: 10.3389/fpls.2022.944515] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2022] [Accepted: 07/20/2022] [Indexed: 05/14/2023]
Abstract
Inositol pyrophosphates (PP-InsPs), derivatives of inositol hexakisphosphate (phytic acid, InsP6) or lower inositol polyphosphates, are energy-rich signaling molecules that have critical regulatory functions in eukaryotes. In plants, the biosynthesis and the cellular targets of these messengers are not fully understood. This is because, in part, plants do not possess canonical InsP6 kinases and are able to synthesize PP-InsP isomers that appear to be absent in yeast or mammalian cells. This review will shed light on recent discoveries in the biosynthesis of these enigmatic messengers and on how they regulate important physiological processes in response to abiotic and biotic stresses in plants.
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Affiliation(s)
- Esther Riemer
- Departmentof Plant Nutrition, Institute of Crop Science and Resource Conservation, Rheinische Friedrich-Wilhelms-Universität Bonn, Bonn, Germany
- *Correspondence: Esther Riemer,
| | | | - Ranjana Yadav
- Department of Biochemistry, Indian Institute of Science, Bengaluru, India
| | - Priyanshi Rana
- Department of Biochemistry, Indian Institute of Science, Bengaluru, India
| | - Henning J. Jessen
- Department of Chemistry and Pharmacy & CIBSS – The Center of Biological Signaling Studies, Albert-Ludwigs University Freiburg, Freiburg, Germany
| | - Marília Kamleitner
- Departmentof Plant Nutrition, Institute of Crop Science and Resource Conservation, Rheinische Friedrich-Wilhelms-Universität Bonn, Bonn, Germany
| | - Gabriel Schaaf
- Departmentof Plant Nutrition, Institute of Crop Science and Resource Conservation, Rheinische Friedrich-Wilhelms-Universität Bonn, Bonn, Germany
| | - Debabrata Laha
- Department of Biochemistry, Indian Institute of Science, Bengaluru, India
- Debabrata Laha,
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3
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Łabuz J, Sztatelman O, Jagiełło-Flasińska D, Hermanowicz P, Bażant A, Banaś AK, Bartnicki F, Giza A, Kozłowska A, Lasok H, Sitkiewicz E, Krzeszowiec W, Gabryś H, Strzałka W. Phototropin Interactions with SUMO Proteins. PLANT & CELL PHYSIOLOGY 2021; 62:693-707. [PMID: 33594440 PMCID: PMC8462379 DOI: 10.1093/pcp/pcab027] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Accepted: 02/10/2021] [Indexed: 06/12/2023]
Abstract
The disruption of the sumoylation pathway affects processes controlled by the two phototropins (phots) of Arabidopsis thaliana, phot1 and phot2. Phots, plant UVA/blue light photoreceptors, regulate growth responses and fast movements aimed at optimizing photosynthesis, such as phototropism, chloroplast relocations and stomatal opening. Sumoylation is a posttranslational modification, consisting of the addition of a SUMO (SMALL UBIQUITIN-RELATED MODIFIER) protein to a lysine residue in the target protein. In addition to affecting the stability of proteins, it regulates their activity, interactions and subcellular localization. We examined physiological responses controlled by phots, phototropism and chloroplast movements, in sumoylation pathway mutants. Chloroplast accumulation in response to both continuous and pulse light was enhanced in the E3 ligase siz1 mutant, in a manner dependent on phot2. A significant decrease in phot2 protein abundance was observed in this mutant after blue light treatment both in seedlings and mature leaves. Using plant transient expression and yeast two-hybrid assays, we found that phots interacted with SUMO proteins mainly through their N-terminal parts, which contain the photosensory LOV domains. The covalent modification in phots by SUMO was verified using an Arabidopsis sumoylation system reconstituted in bacteria followed by the mass spectrometry analysis. Lys 297 was identified as the main target of SUMO3 in the phot2 molecule. Finally, sumoylation of phot2 was detected in Arabidopsis mature leaves upon light or heat stress treatment.
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Affiliation(s)
- Justyna Łabuz
- * Corresponding author: E-mail, ; Fax, +48 12 664 6902
| | | | - Dominika Jagiełło-Flasińska
- Department of Plant Biotechnology, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Gronostajowa 7, Kraków 30-387, Poland
| | - Paweł Hermanowicz
- Laboratory of Photobiology, Malopolska Centre of Biotechnology, Jagiellonian University, Gronostajowa 7A, Kraków 30-387, Poland
| | - Aneta Bażant
- Department of Plant Biotechnology, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Gronostajowa 7, Kraków 30-387, Poland
| | - Agnieszka Katarzyna Banaś
- Department of Plant Biotechnology, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Gronostajowa 7, Kraków 30-387, Poland
| | - Filip Bartnicki
- Department of Plant Biotechnology, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Gronostajowa 7, Kraków 30-387, Poland
| | - Aleksandra Giza
- Department of Plant Biotechnology, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Gronostajowa 7, Kraków 30-387, Poland
| | - Anna Kozłowska
- Laboratory of Photobiology, Malopolska Centre of Biotechnology, Jagiellonian University, Gronostajowa 7A, Kraków 30-387, Poland
| | - Hanna Lasok
- Laboratory of Photobiology, Malopolska Centre of Biotechnology, Jagiellonian University, Gronostajowa 7A, Kraków 30-387, Poland
| | - Ewa Sitkiewicz
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawińskiego 5a, Warszawa 02-106, Poland
| | - Weronika Krzeszowiec
- Department of Plant Biotechnology, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Gronostajowa 7, Kraków 30-387, Poland
| | - Halina Gabryś
- Department of Plant Biotechnology, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Gronostajowa 7, Kraków 30-387, Poland
| | - Wojciech Strzałka
- Department of Plant Biotechnology, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Gronostajowa 7, Kraków 30-387, Poland
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4
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Kamireddy K, Sonbarse PP, Mishra SK, Agrawal L, Chauhan PS, Lata C, Parvatam G. Proteomic approach to identify the differentially abundant proteins during flavour development in tuberous roots of Decalepis hamiltonii Wight & Arn. 3 Biotech 2021; 11:173. [PMID: 33927964 DOI: 10.1007/s13205-021-02714-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Accepted: 03/03/2021] [Indexed: 01/14/2023] Open
Abstract
2-Hydroxy-4-Methoxy Benzaldehyde (2H4MB) is a structural isomer of vanillin produced in the tuberous roots of D. hamiltonii. Both vanillin and 2H4MB share the common phenylpropanoid pathway for their synthesis. Unlike vanillin, in which the biosynthetic pathway was well elucidated in V. planifolia, the 2H4MB biosynthetic pathway is not known in any of its plant sources. To find the key enzymes/proteins that promote 2H4MB biosynthesis, a comparative proteomic approach was adapted. In this case, two developmental stages of tuberous roots of D. hamiltonii were selected, where the flavour content was highly variable. The flavour content in the two stages was estimated using quantitative HPLC. The flavour content in the first and second stages of tuber development was 160 and 510 µgg-1, respectively. Two-dimensional electrophoresis (2-DE) was performed for these two stages of tubers; this was followed by PDquest analysis. A total of 180 protein spots were differentially abundant of which 57 spots were selected and subjected to MALDI-TOF-TOF analysis. The largest percentage of identified proteins was involved in stress and defence (27.9%), followed by proteins related to bioenergy and metabolism (23.2%), Cellular homeostasis proteins (18.6%), signaling proteins (11.6%), Plant growth and development proteins (9.3%). Holistically, we found the upregulation of methyltransferase, cell division responsive proteins, plant growth and development proteins which directly relate to flavour development and maturation. Similarly, stress-responsive and signaling proteins, vacuole proteins and ATPases were down-regulated with an increase in flavour content. In this study, we could not identify the specific 2H4MB metabolic pathway proteins, however, we could be able to study the changes in physiological and primary metabolic proteins with 2H4MB accumulation. SUPPLEMENTARY INFORMATION The online version contains supplementary material available at 10.1007/s13205-021-02714-x.
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Affiliation(s)
- Kiran Kamireddy
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, Uttar Pradesh India
- Plant Cell Biotechnology Department, CSIR - Central Food Technological Research Institute, Mysore, Karnataka India
| | - Priyanka Purushottam Sonbarse
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, Uttar Pradesh India
- Plant Cell Biotechnology Department, CSIR - Central Food Technological Research Institute, Mysore, Karnataka India
| | - Shashank K Mishra
- CSIR-National Botanical Research Institute, Lucknow, Uttar Pradesh India
| | - Lalit Agrawal
- CSIR-National Botanical Research Institute, Lucknow, Uttar Pradesh India
| | - Puneet S Chauhan
- CSIR-National Botanical Research Institute, Lucknow, Uttar Pradesh India
| | - Charu Lata
- CSIR-National Botanical Research Institute, Lucknow, Uttar Pradesh India
| | - Giridhar Parvatam
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, Uttar Pradesh India
- Plant Cell Biotechnology Department, CSIR - Central Food Technological Research Institute, Mysore, Karnataka India
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5
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Na JK, Metzger JD. A putative tomato inositol polyphosphate 5-phosphatase, Le5PT1, is involved in plant growth and abiotic stress responses. 3 Biotech 2020; 10:28. [PMID: 31950007 DOI: 10.1007/s13205-019-2023-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2018] [Accepted: 12/20/2019] [Indexed: 12/16/2022] Open
Abstract
Based on sequence similarity to Arabidopsis inositol polyphosphate 5-phosphatases (5PTases) involved in abiotic stress responses and development, four tomato cDNAs (Le5PT1-4) encoding putative 5PTase proteins were identified. The predicted protein sequences of the Le5PTs include conserved catalytic domains required for 5PTase enzyme activity. Le5PT1, 2, and 3 showed high amino acid sequence identity with At5PTase2, At5PTase1 and At5PTase3, and At5PTase5 and At5PTase6, respectively. The expression of Le5PT1 was downregulated soon after initiation of dehydration and salt stress as well as exposure to polyethylene glycol (PEG) and NaCl, but not by exogenous ABA treatment. On the other hand, the expression of Le5PT2 gradually increased with time in all treatments. Transgenic tobacco plants overexpressing Le5PT1 exhibited reduced growth in height, leaf area, and dry weight compared to wild type plants. Transgenic plants also had lower water use efficiency (WUE) than wild type and the downregulation of the drought-responsive gene, NtERD10B. Together these results suggest that Le5PT1 may have a negative role in response to water deficit through the repression of drought-inducible genes that in turn affects plant growth and development.
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Affiliation(s)
- Jong-Kuk Na
- 1Depeatment of Controlled Agriculture, Kangwon National University, Chuncheon, Republic of Korea
- 2Department of Horticulture and Crop Science, Ohio State University, Columbus, OH 43210 USA
| | - James D Metzger
- 2Department of Horticulture and Crop Science, Ohio State University, Columbus, OH 43210 USA
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6
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Jia Q, Kong D, Li Q, Sun S, Song J, Zhu Y, Liang K, Ke Q, Lin W, Huang J. The Function of Inositol Phosphatases in Plant Tolerance to Abiotic Stress. Int J Mol Sci 2019; 20:ijms20163999. [PMID: 31426386 PMCID: PMC6719168 DOI: 10.3390/ijms20163999] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2019] [Revised: 08/12/2019] [Accepted: 08/13/2019] [Indexed: 02/06/2023] Open
Abstract
Inositol signaling is believed to play a crucial role in various aspects of plant growth and adaptation. As an important component in biosynthesis and degradation of myo-inositol and its derivatives, inositol phosphatases could hydrolyze the phosphate of the inositol ring, thus affecting inositol signaling. Until now, more than 30 members of inositol phosphatases have been identified in plants, which are classified intofive families, including inositol polyphosphate 5-phosphatases (5PTases), suppressor of actin (SAC) phosphatases, SAL1 phosphatases, inositol monophosphatase (IMP), and phosphatase and tensin homologue deleted on chromosome 10 (PTEN)-related phosphatases. The current knowledge was revised here in relation to their substrates and function in response to abiotic stress. The potential mechanisms were also concluded with the focus on their activities of inositol phosphatases. The general working model might be that inositol phosphatases would degrade the Ins(1,4,5)P3 or phosphoinositides, subsequently resulting in altering Ca2+ release, abscisic acid (ABA) signaling, vesicle trafficking or other cellular processes.
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Affiliation(s)
- Qi Jia
- Key Laboratory for Genetics Breeding and Multiple Utilization of Crops, Ministry of Education/College of Crop Science, Fujian Agriculture and Forestry University, Fuzhou 350002, China.
- Key Laboratory of Crop Ecology and Molecular Physiology (Fujian Agriculture and Forestry University), Fujian Province University, Fuzhou 350002, China.
| | - Defeng Kong
- Key Laboratory for Genetics Breeding and Multiple Utilization of Crops, Ministry of Education/College of Crop Science, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Qinghua Li
- Putian Institute of Agricultural Sciences, Putian 351144, China
| | - Song Sun
- Key Laboratory for Genetics Breeding and Multiple Utilization of Crops, Ministry of Education/College of Crop Science, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Junliang Song
- Key Laboratory for Genetics Breeding and Multiple Utilization of Crops, Ministry of Education/College of Crop Science, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Yebao Zhu
- Rice Research Institute, Fujian Academy of Agricultural Sciences, Fuzhou 350018, China
| | - Kangjing Liang
- Key Laboratory for Genetics Breeding and Multiple Utilization of Crops, Ministry of Education/College of Crop Science, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Qingming Ke
- Putian Institute of Agricultural Sciences, Putian 351144, China
| | - Wenxiong Lin
- Key Laboratory for Genetics Breeding and Multiple Utilization of Crops, Ministry of Education/College of Crop Science, Fujian Agriculture and Forestry University, Fuzhou 350002, China
- Key Laboratory of Crop Ecology and Molecular Physiology (Fujian Agriculture and Forestry University), Fujian Province University, Fuzhou 350002, China
| | - Jinwen Huang
- Key Laboratory for Genetics Breeding and Multiple Utilization of Crops, Ministry of Education/College of Crop Science, Fujian Agriculture and Forestry University, Fuzhou 350002, China.
- Key Laboratory of Crop Ecology and Molecular Physiology (Fujian Agriculture and Forestry University), Fujian Province University, Fuzhou 350002, China.
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7
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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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8
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Di Fino LM, D'Ambrosio JM, Tejos R, van Wijk R, Lamattina L, Munnik T, Pagnussat GC, Laxalt AM. Arabidopsis phosphatidylinositol-phospholipase C2 (PLC2) is required for female gametogenesis and embryo development. PLANTA 2017; 245:717-728. [PMID: 27999988 DOI: 10.1007/s00425-016-2634-z] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2016] [Accepted: 12/02/2016] [Indexed: 05/20/2023]
Abstract
AtPLC2 is an essential gene in Arabidopsis, since it is required for female gametogenesis and embryo development. AtPLC2 might play a role in cell division during embryo-sac development and early embryogenesis. Phosphoinositide-specific phospholipase C (PI-PLC) plays an important role in signal transduction during plant development and in the response to various biotic- and abiotic stresses. The Arabidopsis PI-PLC gene family is composed of nine members, named PLC1 to PLC9. Here, we report that PLC2 is involved in female gametophyte development and early embryogenesis. Using two Arabidopsis allelic T-DNA insertion lines with different phenotypic penetrations, we observed both female gametophytic defects and aberrant embryos. For the plc2-1 mutant (Ws background), no homozygous plants could be recovered in the offspring from self-pollinated plants. Nonetheless, plc2-1 hemizygous mutants are affected in female gametogenesis, showing embryo sacs arrested at early developmental stages. Allelic hemizygous plc2-2 mutant plants (Col-0 background) present reduced seed set and embryos arrested at the pre-globular stage with abnormal patterns of cell division. A low proportion (0.8%) of plc2-2 homozygous mutants was found to escape lethality and showed morphological defects and disrupted megagametogenesis. PLC2-promoter activity was observed during early megagametogenesis, and after fertilization in the embryo proper. Immunolocalization studies in early stage embryos revealed that PLC2 is restricted to the plasma membrane. Altogether, these results establish a role for PLC2 in both reproductive- and embryo development, presumably by controlling mitosis and/or the formation of cell-division planes.
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Affiliation(s)
- Luciano M Di Fino
- Instituto de Investigaciones Biológicas IIB-Consejo Nacional de Investigaciones Científicas y Técnicas, Universidad Nacional de Mar del Plata, 7600, Mar del Plata, Argentina
| | - Juan Martín D'Ambrosio
- Instituto de Investigaciones Biológicas IIB-Consejo Nacional de Investigaciones Científicas y Técnicas, Universidad Nacional de Mar del Plata, 7600, Mar del Plata, Argentina
| | - Ricardo Tejos
- Facultad de Recursos Naturales Renovables, Universidad Arturo Prat, 111093, Iquique, Chile
- Centro de Biología Molecular Vegetal, Departamento de Biología, Facultad de Ciencias, Universidad de Chile, 7800003, Santiago, Chile
| | - Ringo van Wijk
- Swammerdam Institute for Life Sciences, Section Plant Cell Biology, University of Amsterdam, 1098 XH, Amsterdam, The Netherlands
| | - Lorenzo Lamattina
- Instituto de Investigaciones Biológicas IIB-Consejo Nacional de Investigaciones Científicas y Técnicas, Universidad Nacional de Mar del Plata, 7600, Mar del Plata, Argentina
| | - Teun Munnik
- Swammerdam Institute for Life Sciences, Section Plant Cell Biology, University of Amsterdam, 1098 XH, Amsterdam, The Netherlands
| | - Gabriela C Pagnussat
- Instituto de Investigaciones Biológicas IIB-Consejo Nacional de Investigaciones Científicas y Técnicas, Universidad Nacional de Mar del Plata, 7600, Mar del Plata, Argentina.
| | - Ana M Laxalt
- Instituto de Investigaciones Biológicas IIB-Consejo Nacional de Investigaciones Científicas y Técnicas, Universidad Nacional de Mar del Plata, 7600, Mar del Plata, Argentina.
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9
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Sparvoli F, Cominelli E. Seed Biofortification and Phytic Acid Reduction: A Conflict of Interest for the Plant? PLANTS 2015; 4:728-55. [PMID: 27135349 PMCID: PMC4844270 DOI: 10.3390/plants4040728] [Citation(s) in RCA: 69] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/03/2015] [Accepted: 11/13/2015] [Indexed: 02/03/2023]
Abstract
Most of the phosphorus in seeds is accumulated in the form of phytic acid (myo-inositol-1,2,3,4,5,6-hexakisphosphate, InsP6). This molecule is a strong chelator of cations important for nutrition, such as iron, zinc, magnesium, and calcium. For this reason, InsP6 is considered an antinutritional factor. In recent years, efforts to biofortify seeds through the generation of low phytic acid (lpa) mutants have been noteworthy. Moreover, genes involved in the biosynthesis and accumulation of this molecule have been isolated and characterized in different species. Beyond its role in phosphorus storage, phytic acid is a very important signaling molecule involved in different regulatory processes during plant development and responses to different stimuli. Consequently, many lpa mutants show different negative pleitotropic effects. The strength of these pleiotropic effects depends on the specific mutated gene, possible functional redundancy, the nature of the mutation, and the spatio-temporal expression of the gene. Breeding programs or transgenic approaches aimed at development of new lpa mutants must take into consideration these different aspects in order to maximize the utility of these mutants.
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Affiliation(s)
- Francesca Sparvoli
- Institute of Agricultural Biology and Biotechnology, CNR, Via Bassini 15, 20133 Milan, Italy.
| | - Eleonora Cominelli
- Institute of Agricultural Biology and Biotechnology, CNR, Via Bassini 15, 20133 Milan, Italy.
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10
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Zhao X, Wang J, Yuan J, Wang XL, Zhao QP, Kong PT, Zhang X. NITRIC OXIDE-ASSOCIATED PROTEIN1 (AtNOA1) is essential for salicylic acid-induced root waving in Arabidopsis thaliana. THE NEW PHYTOLOGIST 2015; 207:211-224. [PMID: 25690466 DOI: 10.1111/nph.13327] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2014] [Accepted: 01/10/2015] [Indexed: 05/07/2023]
Abstract
Root waving responses have been attributed to both environmental and genetics factors, but the potential inducers and transducers of root waving remain elusive. Thus, the identification of novel signal elements related to root waving is an intriguing field of research. Genetic, physiological, cytological, live cell imaging, and pharmacological approaches provide strong evidence for the involvement of Arabidopsis thaliana NITRIC OXIDE-ASSOCIATED PROTEIN1 (AtNOA1) in salicylic acid (SA)-induced root waving. SA specially induced root waving, with an overall decrease in root elongation in A. thaliana, and this SA-induced response was disrupted in the Atnoa1 mutant, as well as in nonexpresser of pathogenesis-related genes 1 (npr1), which is defective in SA-mediated plant defense signal transduction, but not in npr3/4 single and double mutants. The expression assays revealed that the abundance of AtNOA1 was significantly increased by application of SA. Genetic and pharmacological analyses showed that SA-induced root waving involved an AtNOA1-dependent Ca(2+) signal transduction pathway, and PIN-FORMED2 (PIN2) -based polar auxin transport possibly plays a crucial role in this process. Our work suggests that SA signaling through NPR1 and AtNOA1 is involved in the control of root waving, which provides new insights into the mechanisms that control root growth behavior on a hard agar surface.
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Affiliation(s)
- Xiang Zhao
- Institute of Plant Stress Biology, State Key Laboratory of Cotton Biology, School of Life Sciences, Henan University, Kaifeng, 475004, China
| | - Jin Wang
- Institute of Plant Stress Biology, State Key Laboratory of Cotton Biology, School of Life Sciences, Henan University, Kaifeng, 475004, China
| | - Jing Yuan
- Institute of Plant Stress Biology, State Key Laboratory of Cotton Biology, School of Life Sciences, Henan University, Kaifeng, 475004, China
| | - Xi-Li Wang
- Institute of Plant Stress Biology, State Key Laboratory of Cotton Biology, School of Life Sciences, Henan University, Kaifeng, 475004, China
| | - Qing-Ping Zhao
- Institute of Plant Stress Biology, State Key Laboratory of Cotton Biology, School of Life Sciences, Henan University, Kaifeng, 475004, China
| | - Pei-Tao Kong
- Institute of Plant Stress Biology, State Key Laboratory of Cotton Biology, School of Life Sciences, Henan University, Kaifeng, 475004, China
| | - Xiao Zhang
- Institute of Plant Stress Biology, State Key Laboratory of Cotton Biology, School of Life Sciences, Henan University, Kaifeng, 475004, China
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11
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Laha D, Johnen P, Azevedo C, Dynowski M, Weiß M, Capolicchio S, Mao H, Iven T, Steenbergen M, Freyer M, Gaugler P, de Campos MKF, Zheng N, Feussner I, Jessen HJ, Van Wees SCM, Saiardi A, Schaaf G. VIH2 Regulates the Synthesis of Inositol Pyrophosphate InsP8 and Jasmonate-Dependent Defenses in Arabidopsis. THE PLANT CELL 2015; 27:1082-97. [PMID: 25901085 PMCID: PMC4558690 DOI: 10.1105/tpc.114.135160] [Citation(s) in RCA: 106] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2014] [Revised: 03/13/2015] [Accepted: 04/03/2015] [Indexed: 05/20/2023]
Abstract
Diphosphorylated inositol polyphosphates, also referred to as inositol pyrophosphates, are important signaling molecules that regulate critical cellular activities in many eukaryotic organisms, such as membrane trafficking, telomere maintenance, ribosome biogenesis, and apoptosis. In mammals and fungi, two distinct classes of inositol phosphate kinases mediate biosynthesis of inositol pyrophosphates: Kcs1/IP6K- and Vip1/PPIP5K-like proteins. Here, we report that PPIP5K homologs are widely distributed in plants and that Arabidopsis thaliana VIH1 and VIH2 are functional PPIP5K enzymes. We show a specific induction of inositol pyrophosphate InsP8 by jasmonate and demonstrate that steady state and jasmonate-induced pools of InsP8 in Arabidopsis seedlings depend on VIH2. We identify a role of VIH2 in regulating jasmonate perception and plant defenses against herbivorous insects and necrotrophic fungi. In silico docking experiments and radioligand binding-based reconstitution assays show high-affinity binding of inositol pyrophosphates to the F-box protein COI1-JAZ jasmonate coreceptor complex and suggest that coincidence detection of jasmonate and InsP8 by COI1-JAZ is a critical component in jasmonate-regulated defenses.
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Affiliation(s)
- Debabrata Laha
- Center for Plant Molecular Biology, University of Tübingen, 72076 Tübingen, Germany
| | - Philipp Johnen
- Center for Plant Molecular Biology, University of Tübingen, 72076 Tübingen, Germany
| | - Cristina Azevedo
- Medical Research Council Laboratory for Molecular Cell Biology, University College London, London WC1E 6BT, United Kingdom
| | - Marek Dynowski
- Zentrum für Datenverarbeitung, University of Tübingen, 72074 Tübingen, Germany
| | - Michael Weiß
- Department of Biology, University of Tübingen, 72076 Tübingen, Germany
| | | | - Haibin Mao
- Department of Pharmacology, Howard Hughes Medical Institute, University of Washington, Seattle, Washington 98195
| | - Tim Iven
- Department of Plant Biochemistry, Georg-August-University Göttingen, 37077 Göttingen, Germany
| | - Merel Steenbergen
- Plant-Microbe Interactions, Department of Biology, Utrecht University, 3508 TB Utrecht, The Netherlands
| | - Marc Freyer
- Center for Plant Molecular Biology, University of Tübingen, 72076 Tübingen, Germany
| | - Philipp Gaugler
- Center for Plant Molecular Biology, University of Tübingen, 72076 Tübingen, Germany
| | | | - Ning Zheng
- Department of Pharmacology, Howard Hughes Medical Institute, University of Washington, Seattle, Washington 98195
| | - Ivo Feussner
- Department of Plant Biochemistry, Georg-August-University Göttingen, 37077 Göttingen, Germany
| | - Henning J Jessen
- Department of Chemistry, University of Zürich, 8057 Zurich, Switzerland
| | - Saskia C M Van Wees
- Plant-Microbe Interactions, Department of Biology, Utrecht University, 3508 TB Utrecht, The Netherlands
| | - Adolfo Saiardi
- Medical Research Council Laboratory for Molecular Cell Biology, University College London, London WC1E 6BT, United Kingdom
| | - Gabriel Schaaf
- Center for Plant Molecular Biology, University of Tübingen, 72076 Tübingen, Germany
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12
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Sakai Y, Inoue SI, Harada A, Shimazaki KI, Takagi S. Blue-light-induced rapid chloroplast de-anchoring in Vallisneria epidermal cells. JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2015; 57:93-105. [PMID: 25231366 DOI: 10.1111/jipb.12284] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2014] [Accepted: 09/12/2014] [Indexed: 06/03/2023]
Abstract
In the outer periclinal cytoplasm of leaf epidermal cells of an aquatic angiosperm Vallisneria, blue light induces "chloroplast de-anchoring", a rapid decline in the resistance of chloroplasts against centrifugal force. Chloroplast de-anchoring is known induced within 1 min of irradiation with high-fluence-rate blue light specifically, preceding the commencement of chloroplasts migration toward the anticlinal cytoplasm. However, its regulatory mechanism has remained elusive, although pharmacological analysis suggested that a calcium release from intracellular calcium stores is necessary for the response. In search of the responsible photoreceptors, immunoblotting analysis using antibodies against phototropins demonstrated that cross-reactive polypeptides of 120-kDa exist in the plasma-membrane fraction prepared from the leaves. In vitro phosphorylation analysis revealed that 120-kDa polypeptides were phosphorylated by exposure to blue light in a fluence-dependent manner. The blue-light-induced phosphorylation activity was sensitive to a Ser/Thr kinase inhibitor, staurosporine, and unusually was retained at a high level for a long time in darkness. Furthermore, phototropin gene homologs (Vallisneria PHOTOTROPIN1 and PHOTOTROPIN2) expressed in leaves were isolated. We propose that calcium-regulated chloroplast de-anchoring, possibly mediated by phototropins, is an initial process of the blue-light-induced avoidance response of chloroplasts in Vallisneria.
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Affiliation(s)
- Yuuki Sakai
- Department of Biological Sciences, Graduate School of Science, Osaka University, Osaka, 560-0043, Japan
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13
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Aggarwal C, Banaś AK, Kasprowicz-Maluśki A, Borghetti C, Labuz J, Dobrucki J, Gabryś H. Blue-light-activated phototropin2 trafficking from the cytoplasm to Golgi/post-Golgi vesicles. JOURNAL OF EXPERIMENTAL BOTANY 2014; 65:3263-76. [PMID: 24821953 PMCID: PMC4071840 DOI: 10.1093/jxb/eru172] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Phototropins are plasma membrane-localized UVA/blue light photoreceptors which mediate phototropism, inhibition of primary hypocotyl elongation, leaf positioning, chloroplast movements, and stomatal opening. Blue light irradiation activates the C-terminal serine/threonine kinase domain of phototropin which autophosphorylates the receptor. Arabidopsis thaliana encodes two phototropins, phot1 and phot2. In response to blue light, phot1 moves from the plasma membrane into the cytosol and phot2 translocates to the Golgi complex. In this study the molecular mechanism and route of blue-light-induced phot2 trafficking are demonstrated. It is shown that Atphot2 behaves in a similar manner when expressed transiently under 35S or its native promoter. The phot2 kinase domain but not blue-light-mediated autophosphorylation is required for the receptor translocation. Using co-localization and western blotting, the receptor was shown to move from the cytoplasm to the Golgi complex, and then to the post-Golgi structures. The results were confirmed by brefeldin A (an inhibitor of the secretory pathway) which disrupted phot2 trafficking. An association was observed between phot2 and the light chain2 of clathrin via bimolecular fluorescence complementation. The fluorescence was observed at the plasma membrane. The results were confirmed using co-immunoprecipitation. However, tyrphostin23 (an inhibitor of clathrin-mediated endocytosis) and wortmannin (a suppressor of receptor endocytosis) were not able to block phot2 trafficking, indicating no involvement of receptor endocytosis in the formation of phot2 punctuate structures. Protein turnover studies indicated that the receptor was continuously degraded in both darkness and blue light. The degradation of phot2 proceeded via a transport route different from translocation to the Golgi complex.
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Affiliation(s)
- Chhavi Aggarwal
- Department of Plant Biotechnology, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Gronostajowa 7, 30-387 Krakow, Poland
| | - Agnieszka Katarzyna Banaś
- Department of Plant Biotechnology, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Gronostajowa 7, 30-387 Krakow, Poland
| | - Anna Kasprowicz-Maluśki
- Department of Molecular and Cellular Biology, Faculty of Biology, Adam Mickiewicz University, Umultowska 89, 61-614 Poznan, Poland
| | - Carolina Borghetti
- Department of Plant Biotechnology, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Gronostajowa 7, 30-387 Krakow, Poland
| | - Justyna Labuz
- Department of Plant Biotechnology, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Gronostajowa 7, 30-387 Krakow, Poland
| | - Jerzy Dobrucki
- Laboratory of Cell Biophysics, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Gronostajowa 7, 30-387 Krakow, Poland
| | - Halina Gabryś
- Department of Plant Biotechnology, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Gronostajowa 7, 30-387 Krakow, Poland
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14
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Valadares RBS, Perotto S, Santos EC, Lambais MR. Proteome changes in Oncidium sphacelatum (Orchidaceae) at different trophic stages of symbiotic germination. MYCORRHIZA 2014; 24:349-60. [PMID: 24310930 DOI: 10.1007/s00572-013-0547-2] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2013] [Accepted: 11/20/2013] [Indexed: 05/10/2023]
Abstract
Mutualistic symbioses between plants and fungi are a widespread phenomenon in nature. Particularly in orchids, association with symbiotic fungi is required for seed germination and seedling development. During the initial stages of symbiotic germination, before the onset of photosynthesis, orchid protocorms are fully mycoheterotrophic. The molecular mechanisms involved in orchid symbiotic germination and development are largely unknown, but it is likely that changes in plant energy metabolism and defense-related responses play a central role in these processes. We have used 2D-LC-MS/MS coupled to isobaric tagging for relative and absolute quantification to identify proteins with differential accumulation in Oncidium sphacelatum at different stages of mycorrhizal protocorm development (achlorophyllous and green protocorms) after seed inoculation with a Ceratobasidium sp. isolate. We identified and quantified 88 proteins, including proteins putatively involved in energy metabolism, cell rescue and defense, molecular signaling, and secondary metabolism. Quantitative analysis showed that the expected changes in carbon metabolism in green protocorms were accompanied by enhanced accumulation of proteins involved in the modulation of reactive oxygen species homeostasis, defense-related responses, and phytoalexins and carotenoid biosynthesis. Our results suggest profound metabolic changes in orchid protocorms during the switch from the fully mycoheterotrophic to the photosynthetic stage. Part of these changes may be also related to the obligatory nature of the interaction with the endomycorrhizal fungus.
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Affiliation(s)
- R B S Valadares
- Escola Superior de Agricultura "Luiz de Queiroz", Departamento de Ciência do Solo, Universidade de São Paulo, Av. Pádua Dias 11, 13418-900, Piracicaba, São Paulo, Brazil
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15
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Tejos R, Sauer M, Vanneste S, Palacios-Gomez M, Li H, Heilmann M, van Wijk R, Vermeer JEM, Heilmann I, Munnik T, Friml J. Bipolar Plasma Membrane Distribution of Phosphoinositides and Their Requirement for Auxin-Mediated Cell Polarity and Patterning in Arabidopsis. THE PLANT CELL 2014; 26:2114-2128. [PMID: 24876254 PMCID: PMC4079372 DOI: 10.1105/tpc.114.126185] [Citation(s) in RCA: 65] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2014] [Revised: 04/07/2014] [Accepted: 05/05/2014] [Indexed: 05/19/2023]
Abstract
Cell polarity manifested by asymmetric distribution of cargoes, such as receptors and transporters, within the plasma membrane (PM) is crucial for essential functions in multicellular organisms. In plants, cell polarity (re)establishment is intimately linked to patterning processes. Despite the importance of cell polarity, its underlying mechanisms are still largely unknown, including the definition and distinctiveness of the polar domains within the PM. Here, we show in Arabidopsis thaliana that the signaling membrane components, the phosphoinositides phosphatidylinositol 4-phosphate (PtdIns4P) and phosphatidylinositol 4,5-bisphosphate [PtdIns(4,5)P2] as well as PtdIns4P 5-kinases mediating their interconversion, are specifically enriched at apical and basal polar plasma membrane domains. The PtdIns4P 5-kinases PIP5K1 and PIP5K2 are redundantly required for polar localization of specifically apical and basal cargoes, such as PIN-FORMED transporters for the plant hormone auxin. As a consequence of the polarity defects, instructive auxin gradients as well as embryonic and postembryonic patterning are severely compromised. Furthermore, auxin itself regulates PIP5K transcription and PtdIns4P and PtdIns(4,5)P2 levels, in particular their association with polar PM domains. Our results provide insight into the polar domain-delineating mechanisms in plant cells that depend on apical and basal distribution of membrane lipids and are essential for embryonic and postembryonic patterning.
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Affiliation(s)
- Ricardo Tejos
- Department of Plant Systems Biology, VIB, 9052 Ghent, Belgium Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Ghent, Belgium
| | - Michael Sauer
- Department of Plant Systems Biology, VIB, 9052 Ghent, Belgium Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Ghent, Belgium
| | - Steffen Vanneste
- Department of Plant Systems Biology, VIB, 9052 Ghent, Belgium Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Ghent, Belgium
| | | | - Hongjiang Li
- Institute of Science and Technology Austria, 3400 Klosterneuburg, Austria
| | - Mareike Heilmann
- Department of Cellular Biochemistry, Martin-Luther-University Halle-Wittenberg, 06120 Halle (Saale), Germany
| | - Ringo van Wijk
- Swammerdam Institute for Life Sciences, Section Plant Physiology, University of Amsterdam, 1098 XH Amsterdam, The Netherlands
| | - Joop E M Vermeer
- Swammerdam Institute for Life Sciences, Section Plant Physiology, University of Amsterdam, 1098 XH Amsterdam, The Netherlands
| | - Ingo Heilmann
- Department of Cellular Biochemistry, Martin-Luther-University Halle-Wittenberg, 06120 Halle (Saale), Germany
| | - Teun Munnik
- Swammerdam Institute for Life Sciences, Section Plant Physiology, University of Amsterdam, 1098 XH Amsterdam, The Netherlands
| | - Jiří Friml
- Department of Plant Systems Biology, VIB, 9052 Ghent, Belgium Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Ghent, Belgium Institute of Science and Technology Austria, 3400 Klosterneuburg, Austria
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16
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Chong K, Xu Z. Investment in plant research and development bears fruit in China. PLANT CELL REPORTS 2014; 33:541-50. [PMID: 24615161 PMCID: PMC3976507 DOI: 10.1007/s00299-014-1587-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/06/2014] [Revised: 02/05/2014] [Accepted: 02/07/2014] [Indexed: 05/15/2023]
Abstract
Recent rapid progress in plant science and biotechnology in China demonstrates that China's stronger support for funding in plant research and development (R&D) has borne fruit. Chinese groups have contributed major advances in a range of fields, such as rice biology, plant hormone and developmental biology, genomics and evolution, plant genetics and epigenetics, as well as plant biotechnology. Strigolactone studies including those identifying its receptor and dissecting its complex structure and signaling are representative of the recent researches from China at the forefront of the field. These advances are attributable in large part to interdisciplinary studies among scientists from plant science, chemistry, bioinformatics, structural biology, and agronomy. The platforms provided by national facilities facilitate this collaboration. As well, efficient restructuring of the top-down organization of state programs and free exploration of scientists' interests have accelerated achievements by Chinese researchers. Here, we provide a general outline of China's progress in plant R&D to highlight fields in which Chinese research has made significant contributions.
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Affiliation(s)
- Kang Chong
- CAS Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093 China
| | - Zhihong Xu
- College of Life Sciences, Peking University, Beijing, 100871 China
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17
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Im YJ, Smith CM, Phillippy BQ, Strand D, Kramer DM, Grunden AM, Boss WF. Increasing Phosphatidylinositol (4,5)-Bisphosphate Biosynthesis Affects Basal Signaling and Chloroplast Metabolism in Arabidopsis thaliana. PLANTS (BASEL, SWITZERLAND) 2014; 3:27-57. [PMID: 27135490 PMCID: PMC4844314 DOI: 10.3390/plants3010027] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/04/2013] [Revised: 12/18/2013] [Accepted: 12/20/2013] [Indexed: 01/26/2023]
Abstract
One challenge in studying the second messenger inositol(1,4,5)-trisphosphate (InsP₃) is that it is present in very low amounts and increases only transiently in response to stimuli. To identify events downstream of InsP₃, we generated transgenic plants constitutively expressing the high specific activity, human phosphatidylinositol 4-phosphate 5-kinase Iα (HsPIPKIα). PIP5K is the enzyme that synthesizes phosphatidylinositol (4,5)-bisphosphate (PtdIns(4,5)P₂); this reaction is flux limiting in InsP₃ biosynthesis in plants. Plasma membranes from transgenic Arabidopsis expressing HsPIPKIα had 2-3 fold higher PIP5K specific activity, and basal InsP₃ levels in seedlings and leaves were >2-fold higher than wild type. Although there was no significant difference in photosynthetic electron transport, HsPIPKIα plants had significantly higher starch (2-4 fold) and 20% higher anthocyanin compared to controls. Starch content was higher both during the day and at the end of dark period. In addition, transcripts of genes involved in starch metabolism such as SEX1 (glucan water dikinase) and SEX4 (phosphoglucan phosphatase), DBE (debranching enzyme), MEX1 (maltose transporter), APL3 (ADP-glucose pyrophosphorylase) and glucose-6-phosphate transporter (Glc6PT) were up-regulated in the HsPIPKIα plants. Our results reveal that increasing the phosphoinositide (PI) pathway affects chloroplast carbon metabolism and suggest that InsP₃ is one component of an inter-organelle signaling network regulating chloroplast metabolism.
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Affiliation(s)
- Yang Ju Im
- Department of Plant and Microbial Biology, North Carolina State University, Raleigh, NC 27695, USA.
| | - Caroline M Smith
- Department of Plant and Microbial Biology, North Carolina State University, Raleigh, NC 27695, USA.
| | - Brian Q Phillippy
- Department of Plant and Microbial Biology, North Carolina State University, Raleigh, NC 27695, USA.
| | - Deserah Strand
- DOE-Plant Research Laboratory, Michigan State University, East Lansing, MI 48824, USA.
| | - David M Kramer
- DOE-Plant Research Laboratory, Michigan State University, East Lansing, MI 48824, USA.
| | - Amy M Grunden
- Department of Plant and Microbial Biology, North Carolina State University, Raleigh, NC 27695, USA.
| | - Wendy F Boss
- Department of Plant and Microbial Biology, North Carolina State University, Raleigh, NC 27695, USA.
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18
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Vanneste S, Friml J. Calcium: The Missing Link in Auxin Action. PLANTS (BASEL, SWITZERLAND) 2013; 2:650-75. [PMID: 27137397 PMCID: PMC4844386 DOI: 10.3390/plants2040650] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/05/2013] [Revised: 10/07/2013] [Accepted: 10/10/2013] [Indexed: 01/18/2023]
Abstract
Due to their sessile lifestyles, plants need to deal with the limitations and stresses imposed by the changing environment. Plants cope with these by a remarkable developmental flexibility, which is embedded in their strategy to survive. Plants can adjust their size, shape and number of organs, bend according to gravity and light, and regenerate tissues that were damaged, utilizing a coordinating, intercellular signal, the plant hormone, auxin. Another versatile signal is the cation, Ca(2+), which is a crucial second messenger for many rapid cellular processes during responses to a wide range of endogenous and environmental signals, such as hormones, light, drought stress and others. Auxin is a good candidate for one of these Ca(2+)-activating signals. However, the role of auxin-induced Ca(2+) signaling is poorly understood. Here, we will provide an overview of possible developmental and physiological roles, as well as mechanisms underlying the interconnection of Ca(2+) and auxin signaling.
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Affiliation(s)
- Steffen Vanneste
- Plant Systems Biology, VIB, and Plant Biotechnology and Bio-informatics, Ghent University, Ghent 9052, Belgium.
| | - Jiří Friml
- Plant Systems Biology, VIB, and Plant Biotechnology and Bio-informatics, Ghent University, Ghent 9052, Belgium
- Institute of Science and Technology Austria (IST Austria), Klosterneuburg 3400, Austria
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19
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Aggarwal C, Łabuz J, Gabryś H. Phosphoinositides play differential roles in regulating phototropin1- and phototropin2-mediated chloroplast movements in Arabidopsis. PLoS One 2013; 8:e55393. [PMID: 23405144 PMCID: PMC3566141 DOI: 10.1371/journal.pone.0055393] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2012] [Accepted: 12/24/2012] [Indexed: 01/06/2023] Open
Abstract
Phototropins are UVA/blue-light receptors involved in controlling the light-dependent physiological responses which serve to optimize the photosynthetic activity of plants and promote growth. The phototropin-induced phosphoinositide (PI) metabolism has been shown to be essential for stomatal opening and phototropism. However, the role of PIs in phototropin-induced chloroplast movements remains poorly understood. The aim of this work is to determine which PI species are involved in the control of chloroplast movements in Arabidopsis and the nature of their involvement. We present the effects of the inactivation of phospholipase C (PLC), PI3-kinase (PI3K) and PI4-kinase (PI4K) on chloroplast relocations in Arabidopsis. The inhibition of the phosphatidylinositol 4,5-bisphospahte [PI(4,5)P2]-PLC pathway, using neomycin and U73122, suppressed the phot2-mediated chloroplast accumulation and avoidance responses, without affecting movement responses controlled by phot1. On the other hand, PI3K and PI4K activities are more restricted to phot1- and phot2-induced weak-light responses. The inactivation of PI3K and PI4K by wortmannin and LY294002 severely affected the weak blue-light-activated accumulation response but had little effect on the strong blue-light-activated avoidance response. The inhibitory effect observed with PI metabolism inhibitors is, at least partly, due to a disturbance in Ca2+(c) signaling. Using the transgenic aequorin system, we show that the application of these inhibitors suppresses the blue-light-induced transient Ca2+(c) rise. These results demonstrate the importance of PIs in chloroplast movements, with the PI(4,5)P2-PLC pathway involved in phot2 signaling while PI3K and PI4K are required for the phot1- and phot2-induced accumulation response. Our results suggest that these PIs modulate cytosolic Ca2+ signaling during movements.
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Affiliation(s)
- Chhavi Aggarwal
- Department of Plant Biotechnology, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Krakow, Poland
| | - Justyna Łabuz
- Department of Plant Biotechnology, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Krakow, Poland
| | - Halina Gabryś
- Department of Plant Biotechnology, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Krakow, Poland
- * E-mail:
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20
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Gillaspy GE. The Role of Phosphoinositides and Inositol Phosphates in Plant Cell Signaling. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2013; 991:141-57. [DOI: 10.1007/978-94-007-6331-9_8] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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21
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Wang Y, Chu YJ, Xue HW. Inositol polyphosphate 5-phosphatase-controlled Ins(1,4,5)P3/Ca2+ is crucial for maintaining pollen dormancy and regulating early germination of pollen. Development 2012; 139:2221-33. [DOI: 10.1242/dev.081224] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Appropriate pollen germination is crucial for plant reproduction. Previous studies have revealed the importance of dehydration in maintaining pollen dormancy; here, we show that phosphatidylinositol pathway-controlled Ins(1,4,5)P3/Ca2+ levels are crucial for maintaining pollen dormancy in Arabidopsis thaliana. An interesting phenotype, precocious pollen germination within anthers, results from a disruption of inositol polyphosphate 5-phosphatase 12 (5PT12). The knockout mutant 5pt12 has normal early pollen development and pollen dehydration, and exhibits hypersensitive ABA responses, indicating that precocious pollen germination is not caused either by abnormal dehydration or by suppressed ABA signaling. Deficiency of 5PT13 (a close paralog of 5PT12) synergistically enhances precocious pollen germination. Both basal Ins(1,4,5)P3 levels and endogenous Ca2+ levels are elevated in pollen from 5pt12 mutants, and 5pt12 5pt13 double mutants show an even higher precocious germination rate along with much higher levels of Ins(1,4,5)P3/Ca2+. Strikingly, exogenous Ca2+ stimulates the germination of wild-type pollen at floral stage 12, even in very low humidity, both in vitro and in vivo, and treatment with BAPTA, a [Ca2+]cyt inhibitor, reduces the precocious pollen germination rates of 5pt12, 5pt13 and 5pt12 5pt13 mutants. These results indicate that the increase in the levels of Ins(1,4,5)P3/Ca2+ caused by deficiency of inositol polyphosphate 5-phosphatases is sufficient to break pollen dormancy and to trigger early germination. The study reveals that independent of dehydration, the control of Ins(1,4,5)P3/Ca2+ levels by Inositol polyphosphate 5-phosphatases is crucial for maintaining pollen dormancy.
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Affiliation(s)
- Yuan Wang
- National Key Laboratory of Plant Molecular Genetics, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, 300 Fenglin Road, Shanghai 200032, China
| | - Yu-Jia Chu
- National Key Laboratory of Plant Molecular Genetics, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, 300 Fenglin Road, Shanghai 200032, China
| | - Hong-Wei Xue
- National Key Laboratory of Plant Molecular Genetics, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, 300 Fenglin Road, Shanghai 200032, China
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Łabuz J, Sztatelman O, Banaś AK, Gabryś H. The expression of phototropins in Arabidopsis leaves: developmental and light regulation. JOURNAL OF EXPERIMENTAL BOTANY 2012; 63:1763-71. [PMID: 22371325 DOI: 10.1093/jxb/ers061] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
Phototropins are blue light receptors, which play different roles during plant development. Two phototropins of Arabidopsis thaliana, phot1 and phot2, have strongly overlapping functions. In seedlings, both photoreceptors are responsible for phototropism. In mature leaves they redundantly regulate leaf shape, stomatal opening, and the accumulation of chloroplasts, whereas phototropin2 alone controls chloroplast avoidance response. Light not only activates phototropins, but also affects the level of their expression. In Arabidopsis seedlings, PHOT1 is downregulated and PHOT2 is upregulated by light. Since data on transcription levels of phototropins in mature Arabidopsis leaves is scarce, a comprehensive real-time PCR study of PHOT1 and PHOT2 expression during development was performed, from seedlings to senescing leaves. So far, neither the phototropin expression nor its modulation by light have been investigated during senescence. The results show that the general regulation pattern remains conserved during Arabidopsis lifecycle, whereas the level of transcripts fluctuates over time, pointing to the significance of the light control for functioning of phototropins. The second part of the study determined the influence of photosynthesis-derived signals and photoreceptor-activated transduction pathways on phototropin mRNA levels. The effects of blue and red light were examined using Arabidopsis mutant lines deficient in photoreceptors. The results reveal a complex network of interactions between these receptors in the regulation of phototropin transcription profiles. Cryptochrome1 and phytochromeB appear to be main photoreceptors involved in the regulation of PHOT1 transcript accumulation. The expression of PHOT2 is dependent on both cryptochromes and phytochromeA.
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Affiliation(s)
- Justyna Łabuz
- Department of Plant Biotechnology, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Gronostajowa 7, 30-387 Krakow, Poland
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23
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Banaś AK, Aggarwal C, Łabuz J, Sztatelman O, Gabryś H. Blue light signalling in chloroplast movements. JOURNAL OF EXPERIMENTAL BOTANY 2012; 63:1559-74. [PMID: 22312115 DOI: 10.1093/jxb/err429] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Chloroplast movements are among the mechanisms allowing plants to cope with changes in their environment. Chloroplasts accumulate at illuminated cell areas under weak light while they avoid areas exposed to strong light. These directional responses may be controlled by blue and/or red light, depending on the plant group. In terrestrial angiosperms only the blue light perceived by phototropins is active. The last decade has seen a rapid development of studies on the mechanism of directional chloroplast movements, which started with an identification of the photoreceptors. A forward genetic approach has been used to identify the components which control chloroplast movements. This review summarizes the current state of research into the signalling pathways which lead to chloroplast responses. First, the molecular properties of phototropins are presented, followed by a characterization both of proteins which are active downstream of phototropins and of secondary messengers. Finally, cross-talk between light signalling involved in chloroplast movements and other signalling pathways is discussed.
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Affiliation(s)
- Agnieszka Katarzyna Banaś
- Department of Plant Biotechnology, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Gronostajowa 7, 30-387 Krakow, Poland
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Abstract
"All things flow and change…even in the stillest matter there is unseen flux and movement." Attributed to Heraclitus (530-470 BC), from The Story of Philosophy by Will Durant. Heraclitus, a Greek philosopher, was thinking on a much larger scale than molecular signaling; however, his visionary comments are an important reminder for those studying signaling today. Even in unstimulated cells, signaling pathways are in constant metabolic flux and provide basal signals that travel throughout the organism. In addition, negatively charged phospholipids, such as the polyphosphorylated inositol phospholipids, provide a circuit board of on/off switches for attracting or repelling proteins that define the membranes of the cell. This template of charged phospholipids is sensitive to discrete changes and metabolic fluxes-e.g., in pH and cations-which contribute to the oscillating signals in the cell. The inherent complexities of a constantly fluctuating system make understanding how plants integrate and process signals challenging. In this review we discuss one aspect of lipid signaling: the inositol family of negatively charged phospholipids and their functions as molecular sensors and regulators of metabolic flux in plants.
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Affiliation(s)
- Wendy F Boss
- Department of Plant Biology, North Carolina State University, Raleigh, NC 27695-7649, USA.
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Alimohammadi M, de Silva K, Ballu C, Ali N, Khodakovskaya MV. Reduction of inositol (1,4,5)-trisphosphate affects the overall phosphoinositol pathway and leads to modifications in light signalling and secondary metabolism in tomato plants. JOURNAL OF EXPERIMENTAL BOTANY 2012; 63:825-35. [PMID: 21994174 PMCID: PMC3254682 DOI: 10.1093/jxb/err306] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/25/2011] [Revised: 08/26/2011] [Accepted: 08/30/2011] [Indexed: 05/07/2023]
Abstract
The phosphoinositol pathway is one of the major eukaryotic signalling pathways. The metabolite of the phosphoinositol pathway, inositol- (1,4,5) trisphosphate (InsP(3)), is a regulator of plant responses to a wide variety of stresses, including light, drought, cold, and salinity. It was found that the expression of InsP 5-ptase, the enzyme that hydrolyses InsP(3), also dramatically affects the levels of inositol phosphate metabolites and the secondary metabolites in transgenic tomato plants. Tomato plants expressing InsP 5-ptase exhibited a reduction in the levels of several important inositol phosphates, including InsP(1), InsP(2), InsP(3), and InsP(4). Reduced levels of inositol phosphates accompanied an increase in the accumulation of phenylpropanoids (rutin, chlorogenic acid) and ascorbic acid (vitamin C) in the transgenic fruits of tomato plants. The enhanced accumulation of these metabolites in transgenic tomato plants was in direct correspondence with the observed up-regulation of the genes that express the key enzymes of ascorbic acid metabolism (myo-inositol oxygenase, MIOX; L-galactono-γ-lactone dehydrogenase, GLDH) and phenylpropanoid metabolism (chalcone synthase, CHS1; cinnamoyl-CoA shikimate/quinate transferase, HCT). To understand the molecular links between the activation of different branches of plant metabolism and InsP(3) reduction in tomato fruits, the expression of transcription factors known to be involved in light signalling was analysed by real-time RT-PCR. The expression of LeHY5, SIMYB12, and LeELIP was found to be higher in fruits expressing InsP 5-ptase. These results suggest possible interconnections between phosphoinositol metabolism, light signalling, and secondary metabolism in plants. Our study also revealed the biotechnological potential for the genetic improvement of crop plants by the manipulation of the phosphoinositol pathway.
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Affiliation(s)
- Mohammad Alimohammadi
- Department of Applied Science, University of Arkansas at Little Rock, Little Rock, AR, 72204, USA
| | - Kanishka de Silva
- Department of Applied Science, University of Arkansas at Little Rock, Little Rock, AR, 72204, USA
| | - Clarisse Ballu
- Department of Applied Science, University of Arkansas at Little Rock, Little Rock, AR, 72204, USA
- CFAI EIA – ITII Poitou-Charentes, La Couronne, France, 16400
| | - Nawab Ali
- Graduate Institute of Technology, University of Arkansas at Little Rock, Little Rock, AR, 72204, USA
| | - Mariya V. Khodakovskaya
- Department of Applied Science, University of Arkansas at Little Rock, Little Rock, AR, 72204, USA
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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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Kaye Y, Golani Y, Singer Y, Leshem Y, Cohen G, Ercetin M, Gillaspy G, Levine A. Inositol polyphosphate 5-phosphatase7 regulates the production of reactive oxygen species and salt tolerance in Arabidopsis. PLANT PHYSIOLOGY 2011; 157:229-41. [PMID: 21677096 PMCID: PMC3165872 DOI: 10.1104/pp.111.176883] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
Plants possess remarkable ability to adapt to adverse environmental conditions. The adaptation process involves the removal of many molecules from organelles, especially membranes, and replacing them with new ones. The process is mediated by an intracellular vesicle-trafficking system regulated by phosphatidylinositol (PtdIns) kinases and phosphatases. Although PtdIns comprise a fraction of membrane lipids, they function as major regulators of stress signaling. We analyzed the role of PtdIns 5-phosphatases (5PTases) in plant salt tolerance. The Arabidopsis (Arabidopsis thaliana) genome contains 15 At5PTases. We analyzed salt sensitivity in nine At5ptase mutants and identified one (At5ptase7) that showed increased sensitivity, which was improved by overexpression. At5ptase7 mutants demonstrated reduced production of reactive oxygen species (ROS). Supplementation of mutants with exogenous PtdIns dephosphorylated at the D5' position restored ROS production, while PtdIns(4,5)P(2), PtdIns(3,5)P(2), or PtdIns(3,4,5)P(3) were ineffective. Compromised salt tolerance was also observed in mutant NADPH Oxidase, in agreement with the low ROS production and salt sensitivity of PtdIns 3-kinase mutants and with the inhibition of NADPH oxidase activity in wild-type plants. Localization of green fluorescent protein-labeled At5PTase7 occurred in the plasma membrane and nucleus, places that coincided with ROS production. Analysis of salt-responsive gene expression showed that mutants failed to induce the RD29A and RD22 genes, which contain several ROS-dependent elements in their promoters. Inhibition of ROS production by diphenylene iodonium suppressed gene induction. In summary, our results show a nonredundant function of At5PTase7 in salt stress response by regulating ROS production and gene expression.
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Wang GY, Shi JL, Ng G, Battle SL, Zhang C, Lu H. Circadian clock-regulated phosphate transporter PHT4;1 plays an important role in Arabidopsis defense. MOLECULAR PLANT 2011; 4:516-26. [PMID: 21447757 PMCID: PMC3988428 DOI: 10.1093/mp/ssr016] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2010] [Accepted: 02/10/2011] [Indexed: 05/18/2023]
Abstract
The Arabidopsis accelerated cell death 6-1 (acd6-1) mutant shows constitutive defense, cell death, and extreme dwarf phenotypes. In a screen for acd6-1 suppressors, we identified a mutant that was disrupted by a T-DNA in the PHOSPHATE TRANSPORTER 4;1 (PHT4;1) gene. The suppressor mutant pht4;1-1 is dominant, expresses truncated PHT4;1 transcripts, and is more susceptible to virulent Pseudomonas syringae strains but not to several avirulent strains. Treatment with a salicylic acid (SA) agonist induced a similar level of resistance in Col-0 and pht4;1-1, suggesting that PHT4;1 acts upstream of the SA pathway. Genetic analysis further indicates that PHT4;1 contributes to SID2-dependent and -independent pathways. Transgenic expression of the DNA fragment containing the PHT4;1-1 region or the full-length PHT4;1 gene in wild-type conferred enhanced susceptibility to Pseudomonas infection. Interestingly, expression of PHT4;1 is regulated by the circadian clock. Together, these data suggest that the phosphate transporter PHT4;1 is critical for basal defense and also implicate a potential role of the circadian clock in regulating innate immunity of Arabidopsis.
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Affiliation(s)
| | | | | | | | | | - Hua Lu
- Department of Biological Sciences, University of Maryland Baltimore County, 1000 Hilltop Circle, Baltimore, MD 21250, USA
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Giammaria V, Grandellis C, Bachmann S, Gargantini PR, Feingold SE, Bryan G, Ulloa RM. StCDPK2 expression and activity reveal a highly responsive potato calcium-dependent protein kinase involved in light signalling. PLANTA 2011; 233:593-609. [PMID: 21132327 DOI: 10.1007/s00425-010-1319-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2010] [Accepted: 11/12/2010] [Indexed: 05/11/2023]
Abstract
Calcium-dependent protein kinases (CDPKs) are essential calcium sensors. In this work, we have studied StCDPK2 isoform from potato both at gene and protein level. StCdpk2 genomic sequence contains eight exons and seven introns, as was observed for StCdpk1. There is one copy of the gene per genome located in chromosome 7. StCDPK2 encodes an active CDPK of 515 aminoacids, with an apparent MW of 57 kDa, which presents myristoylation and palmitoylation consensus in its N-terminus. StCDPK2 is highly expressed in leaves and green sprouts; enhanced expression was detected under light treatment, which corresponds well with light responsive cis-acting elements found in its promoter sequence. Antibodies against the recombinant StCDPK2::6xHis protein detected this isoform in soluble and particulate fractions from leaves. StCDPK2 autophosphorylation and kinase activity are both calcium dependent reaching half maximal activation at 0.6 μM calcium. The active kinase is autophosphorylated on serine and tyrosine residues and its activity is negatively modulated by phosphatidic acid (PA). Our results reveal StCDPK2 as a signalling element involved in plant growth and development and show that its activity is tightly regulated.
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Affiliation(s)
- Verónica Giammaria
- Instituto de Investigaciones en Ingeniería Genética y Biología Molecular (INGEBI), CONICET and Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Vuelta de Obligado 2490 2do piso, 1428, Buenos Aires, Argentina
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Effendi Y, Rietz S, Fischer U, Scherer GFE. The heterozygous abp1/ABP1 insertional mutant has defects in functions requiring polar auxin transport and in regulation of early auxin-regulated genes. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2011; 65:282-94. [PMID: 21223392 DOI: 10.1111/j.1365-313x.2010.04420.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
AUXIN-BINDING PROTEIN 1 (ABP1) is not easily accessible for molecular studies because the homozygous T-DNA insertion mutant is embryo-lethal. We found that the heterozygous abp1/ABP1 insertion mutant has defects in auxin physiology-related responses: higher root slanting angles, longer hypocotyls, agravitropic roots and hypocotyls, aphototropic hypocotyls, and decreased apical dominance. Heterozygous plants flowered earlier than wild-type plants under short-day conditions. The length of the main root, the lateral root density and the hypocotyl length were little altered in the mutant in response to auxin. Compared to wild-type plants, transcription of early auxin-regulated genes (IAA2, IAA11, IAA13, IAA14, IAA19, IAA20, SAUR9, SAUR15, SAUR23, GH3.5 and ABP1) was less strongly up-regulated in the mutant by 0.1, 1 and 10 μm IAA. Surprisingly, ABP1 was itself an early auxin-up-regulated gene. IAA uptake into the mutant seedlings during auxin treatments was indistinguishable from wild-type. Basipetal auxin transport in young roots was slower in the mutant, indicating a PIN2/EIR1 defect, while acropetal transport was indistinguishable from wild-type. In the eir1 background, three of the early auxin-regulated genes tested (IAA2, IAA13 and ABP1) were more strongly induced by 1 μm IAA in comparison to wild-type, but eight of them were less up-regulated in comparison to wild-type. Similar but not identical disturbances in regulation of early auxin-regulated genes indicate tight functional linkage of ABP1 and auxin transport regulation. We hypothesize that ABP1 is involved in the regulation of polar auxin transport, and thus affects local auxin concentration and early auxin gene regulation. In turn, ABP1 itself is under the transcriptional control of auxin.
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Affiliation(s)
- Yunus Effendi
- Leibniz Universität Hannover, Institut für Zierpflanzenbau und Gehölzforschung, Abt. Molekulare Ertragsphysiologie, Herrenhäuser Straße 2, D-30419 Hannover, Germany
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31
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Gaussand GMDJM, Jia Q, van der Graaff E, Lamers GEM, Fransz PF, Hooykaas PJJ, de Pater S. Programmed Cell Death in the Leaves of the Arabidopsis Spontaneous Necrotic Spots (sns-D) Mutant Correlates with Increased Expression of the Eukaryotic Translation Initiation Factor eIF4B2. FRONTIERS IN PLANT SCIENCE 2011; 2:9. [PMID: 22639576 PMCID: PMC3355676 DOI: 10.3389/fpls.2011.00009] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2011] [Accepted: 03/28/2011] [Indexed: 05/20/2023]
Abstract
From a pool of transgenic Arabidopsis (Arabidopsis thaliana) plants harboring an activator T-DNA construct, one mutant was identified that developed spontaneous necrotic spots (sns-D) on the rosette leaves under aseptic conditions. The sns-D mutation is dominant and homozygous plants are embryo lethal. The mutant produced smaller rosettes with a different number of stomata than the wild-type. DNA fragmentation in the nuclei of cells in the necrotic spots and a significant increase of caspase-3 and caspase-6 like activities in sns-D leaf extracts indicated that the sns-D mutation caused programmed cell death (PCD). The integration of the activator T-DNA caused an increase of the expression level of At1g13020, which encodes the eukaryotic translation initiation factor eIF4B2. The expression level of eIF4B2 was positively correlated with the severity of sns-D mutant phenotype. Overexpression of the eIF4B2 cDNA mimicked phenotypic traits of the sns-D mutant indicating that the sns-D mutant phenotype is indeed caused by activation tagging of eIF4B2. Thus, incorrect regulation of translation initiation may result in PCD.
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Affiliation(s)
- Gwénaël M. D. J.-M. Gaussand
- Molecular and Developmental Genetics Department, Institute of Biology Leiden, Leiden UniversityLeiden, Netherlands
| | - Qi Jia
- Molecular and Developmental Genetics Department, Institute of Biology Leiden, Leiden UniversityLeiden, Netherlands
| | - Eric van der Graaff
- Molecular and Developmental Genetics Department, Institute of Biology Leiden, Leiden UniversityLeiden, Netherlands
| | - Gerda E. M. Lamers
- Molecular and Developmental Genetics Department, Institute of Biology Leiden, Leiden UniversityLeiden, Netherlands
| | - Paul F. Fransz
- Swammerdam Institute for Life Sciences, University of AmsterdamAmsterdam, Netherlands
| | - Paul J. J. Hooykaas
- Molecular and Developmental Genetics Department, Institute of Biology Leiden, Leiden UniversityLeiden, Netherlands
| | - Sylvia de Pater
- Molecular and Developmental Genetics Department, Institute of Biology Leiden, Leiden UniversityLeiden, Netherlands
- *Correspondence: Sylvia de Pater, Sylvius Laboratory, Molecular and Developmental Genetics Department, Institute of Biology, Leiden University, Sylviusweg 72, 2333 BE Leiden, Netherlands. e-mail:
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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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Pedmale UV, Celaya RB, Liscum E. Phototropism: mechanism and outcomes. THE ARABIDOPSIS BOOK 2010; 8:e0125. [PMID: 22303252 PMCID: PMC3244944 DOI: 10.1199/tab.0125] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Plants have evolved a wide variety of responses that allow them to adapt to the variable environmental conditions in which they find themselves growing. One such response is the phototropic response - the bending of a plant organ toward (stems and leaves) or away from (roots) a directional blue light source. Phototropism is one of several photoresponses of plants that afford mechanisms to alter their growth and development to changes in light intensity, quality and direction. Over recent decades much has been learned about the genetic, molecular and cell biological components involved in sensing and responding to phototropic stimuli. Many of these advances have been made through the utilization of Arabidopsis as a model for phototropic studies. Here we discuss such advances, as well as studies in other plant species where appropriate to the discussion of work in Arabidopsis.
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Affiliation(s)
- Ullas V. Pedmale
- Division of Biological Sciences and Christopher S. Bond Life Sciences Center, University of Missouri, Columbia, MO 65211
| | - R. Brandon Celaya
- Division of Biological Sciences and Christopher S. Bond Life Sciences Center, University of Missouri, Columbia, MO 65211
- Department of Molecular, Cellular and Developmental Biology, University of California — Los Angeles, 3206 Life Science Bldg, 621 Charles E Young Dr, Los Angeles, CA 90095
| | - Emmanuel Liscum
- Division of Biological Sciences and Christopher S. Bond Life Sciences Center, University of Missouri, Columbia, MO 65211
- Address correspondence to
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35
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Zhang Y, McCormick S. AGCVIII kinases: at the crossroads of cellular signaling. TRENDS IN PLANT SCIENCE 2009; 14:689-695. [PMID: 19818674 DOI: 10.1016/j.tplants.2009.09.006] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2009] [Revised: 09/10/2009] [Accepted: 09/14/2009] [Indexed: 05/28/2023]
Abstract
AGCVIII kinases regulate diverse developmental and cellular processes in plants. As putative mediators of secondary messengers, AGCVIII kinases potentially integrate developmental and environmental cues into specific cellular responses through substrate phosphorylation. Here we discuss the functionality and regulation of AGCVIII kinases. Specifically, we question the view that activities of AGCVIII kinases, like their animal counterparts, are regulated by a common regulator, 3-phosphoinositide-dependent protein kinase-1 (PDK1). Instead, increasing evidence suggests that Ca(2+) and phospholipids regulate AGCVIII kinases, by altering their activities or by affecting their subcellular localization. As AGCVIII kinases are at the crossroads of plant cellular signaling, they and the signaling networks in which they participate are keys to a better understanding of plant development and of interactions with their environment.
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Affiliation(s)
- Yan Zhang
- Plant Gene Expression Center, United States Department of Agriculture/Agricultural Research Service, and Department of Plant and Microbial Biology, University of California at Berkeley, 800 Buchanan St., Albany, CA 94710, 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: 2.3] [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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Carland F, Nelson T. CVP2- and CVL1-mediated phosphoinositide signaling as a regulator of the ARF GAP SFC/VAN3 in establishment of foliar vein patterns. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2009; 59:895-907. [PMID: 19473324 DOI: 10.1111/j.1365-313x.2009.03920.x] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
In foliar organs of dicots, veins are arranged in a highly branched or reticulated pattern for efficient distribution of water, photosynthates and signaling molecules. Recent evidence suggests that the patterns rely in part on regulation of intracellular vesicle transport and cell polarity in selected cells during leaf development. The sorting of vesicle cargos to discrete cellular sites is regulated in yeast and animal cells by the binding of specific phosphoinositides (PIs). We report here that, in the plant Arabidopsis, specific PIs guide the vesicle traffic that is essential for polarized and continuous vein pattern formation. Mutations in SFC/VAN3, an ADP-ribosylation factor GTPase-activating protein (ARF GAP) with a PI-binding pleckstrin homology domain, result in discontinuous vein patterns. Plants with mutations in both CVP2 and CVL1, which encode inositol polyphosphate 5'-phosphatases that generate the specific PI ligand for the pleckstrin homology domain of SFC/VAN3, phosphatidylinositol-4-monophosphate (PI(4)P), have a discontinuous vein phenotype identical to that of sfc/van3 mutants. Single cvp2 or cvl1 mutants show weak and no discontinuous vein phenotypes, respectively, suggesting that they act redundantly. We propose that these two 5'-phosphatases regulate vein continuity and cell polarity by generating a specific PI ligand for SFC/VAN3.
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Affiliation(s)
- Francine Carland
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT 06520, USA
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39
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Abstract
As an important metabolic pathway, phosphatidylinositol metabolism generates both constitutive and signalling molecules that are crucial for plant growth and development. Recent studies using genetic and molecular approaches reveal the important roles of phospholipid molecules and signalling in multiple processes of higher plants, including root growth, pollen and vascular development, hormone effects and cell responses to environmental stimuli plants. The present review summarizes the current progress in our understanding of the functional mechanism of phospholipid signalling, with an emphasis on the regulation of Ins(1,4,5)P3-Ca2+ oscillation, the second messenger molecule phosphatidic acid and the cytoskeleton.
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Stimpson AJ, Pereira RS, Kiss JZ, Correll MJ. Extraction and labeling methods for microarrays using small amounts of plant tissue. PHYSIOLOGIA PLANTARUM 2009; 135:229-236. [PMID: 19140889 DOI: 10.1111/j.1399-3054.2008.01191.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Procedures were developed to maximize the yield of high-quality RNA from small amounts of plant biomass for microarrays. Two disruption techniques (bead milling and pestle and mortar) were compared for the yield and the quality of RNA extracted from 1-week-old Arabidopsis thaliana seedlings (approximately 0.5-30 mg total biomass). The pestle and mortar method of extraction showed enhanced RNA quality at the smaller biomass samples compared with the bead milling technique, although the quality in the bead milling could be improved with additional cooling steps. The RNA extracted from the pestle and mortar technique was further tested to determine if the small quantity of RNA (500 ng-7 microg) was appropriate for microarray analyses. A new method of low-quantity RNA labeling for microarrays (NuGEN Technologies, Inc.) was used on five 7-day-old seedlings (approximately 2.5 mg fresh weight total) of Arabidopsis that were grown in the dark and exposed to 1 h of red light or continued dark. Microarray analyses were performed on a small plant sample (five seedlings; approximately 2.5 mg) using these methods and compared with extractions performed with larger biomass samples (approximately 500 roots). Many well-known light-regulated genes between the small plant samples and the larger biomass samples overlapped in expression changes, and the relative expression levels of selected genes were confirmed with quantitative real-time polymerase chain reaction, suggesting that these methods can be used for plant experiments where the biomass is extremely limited (i.e. spaceflight studies).
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Affiliation(s)
- Alexander J Stimpson
- Department of Agricultural and Biological Engineering, University of Florida, Gainesville, 32611, USA
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Demarsy E, Fankhauser C. Higher plants use LOV to perceive blue light. CURRENT OPINION IN PLANT BIOLOGY 2009; 12:69-74. [PMID: 18930433 DOI: 10.1016/j.pbi.2008.09.002] [Citation(s) in RCA: 144] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2008] [Accepted: 09/02/2008] [Indexed: 05/20/2023]
Abstract
Higher plants use several classes of blue light receptors to modulate a wide variety of physiological responses. Among them, both the phototropins and members of the Zeitlupe (ZTL) family use light oxygen voltage (LOV) photosensory domains. In Arabidopsis, these families comprise phot1, phot2 and ZTL, LOV Kelch Protein 2 (LKP2), and Flavin-binding Kelch F-box1 (FKF1). It has now been convincingly shown that blue-light-induced autophosphorylation of the phot1 kinase domain is an essential step in signal transduction. Recent experiments also shed light on the partially distinct photosensory specificities of phot1 and phot2. Phototropin signaling branches rapidly following photoreceptor activation to mediate distinct responses such as chloroplast movements or phototropism. Light activation of the LOV domain in ZTL family members modulates their capacity to interact with GIGANTEA (GI) and their ubiquitin E3 ligase activity. A complex between GI and FKF1 is required to trigger the degradation of a repressor of CO (CONSTANS) expression and thus modulates flowering time. In contrast, light-regulated complex formation between ZTL and GI appears to limit the capacity of ZTL to degrade its targets, which are part of the circadian oscillator.
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Affiliation(s)
- Emilie Demarsy
- Center for Integrative Genomics, University of Lausanne, Genopode Building, Lausanne, Switzerland.
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Abstract
Since the discovery of the phosphoinositide/phospholipase C (PI/PLC) system in animal systems, we know that phospholipids are much more then just structural components of biological membranes. In the beginning, this idea was fairly straightforward. Receptor stimulation activates PLC, which hydrolyses phosphatidylinositol4,5-bisphosphate [PtdIns(4,5)P2] into two second messengers: inositol 1,4,5-trisphosphate (InsP3) and diacylglycerol (DG). While InsP3 difuses into the cytosol and triggers the release of calcium from an internal store via ligand-gated calcium channels, DG remains in the membrane where it recruits and activates members of the PKC family. The increase in calcium, together with the change in phosphorylation status, (in)activates a variety of protein targets, leading to a massive reprogramming, allowing the cell to appropriately respond to the extracellular stimulus. Later, it became obvious that not just PLC, but a variety of other phospholipid-metabolizing enzymes were activated, including phospholipase A, phospholipase D, and PI 3-kinase. More recently, it has become apparent that PtdIns4P and PtdIns(4,5)P2 are not just signal precursors but can also function as signaling molecules themselves. While plants contain most of the components described above, and evidence for their role in cell signaling is progressively increasing, major differences between plants and the mammalian paradigms exist. Below, these are described "in a nutshell."
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Affiliation(s)
- Teun Munnik
- Section of Plant Physiology, Swammerdam Institute for Life Sciences, University of Amsterdam, NL-1098SM, Amsterdam, The Netherlands.
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Ananieva EA, Gillaspy GE, Ely A, Burnette RN, Erickson FL. Interaction of the WD40 domain of a myoinositol polyphosphate 5-phosphatase with SnRK1 links inositol, sugar, and stress signaling. PLANT PHYSIOLOGY 2008; 148:1868-82. [PMID: 18931139 PMCID: PMC2593651 DOI: 10.1104/pp.108.130575] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2008] [Accepted: 10/14/2008] [Indexed: 05/17/2023]
Abstract
In plants, myoinositol signaling pathways have been associated with several stress, developmental, and physiological processes, but the regulation of these pathways is largely unknown. In our efforts to better understand myoinositol signaling pathways in plants, we have found that the WD40 repeat region of a myoinositol polyphosphate 5-phosphatase (5PTase13; At1g05630) interacts with the sucrose nonfermenting-1-related kinase (SnRK1.1) in the yeast two-hybrid system and in vitro. Plant SnRK1 proteins (also known as AKIN10/11) have been described as central integrators of sugar, metabolic, stress, and developmental signals. Using mutants defective in 5PTase13, we show that 5PTase13 can act as a regulator of SnRK1 activity and that regulation differs with different nutrient availability. Specifically, we show that under low-nutrient or -sugar conditions, 5PTase13 acts as a positive regulator of SnRK1 activity. In contrast, under severe starvation conditions, 5PTase13 acts as a negative regulator of SnRK1 activity. To delineate the regulatory interaction that occurs between 5PTase13 and SnRK1.1, we used a cell-free degradation assay and found that 5PTase13 is required to reduce the amount of SnRK1.1 targeted for proteasomal destruction under low-nutrient conditions. This regulation most likely involves a 5PTase13-SnRK1.1 interaction within the nucleus, as a 5PTase13:green fluorescent protein was localized to the nucleus. We also show that a loss of function in 5PTase13 leads to nutrient level-dependent reduction of root growth, along with abscisic acid (ABA) and sugar insensitivity. 5ptase13 mutants accumulate less inositol 1,4,5-trisphosphate in response to sugar stress and have alterations in ABA-regulated gene expression, both of which are consistent with the known role of inositol 1,4,5-trisphosphate in ABA-mediated signaling. We propose that by forming a protein complex with SnRK1.1 protein, 5PTase13 plays a regulatory role linking inositol, sugar, and stress signaling.
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Affiliation(s)
- Elitsa A Ananieva
- Department of Biochemistry, Virginia Tech, Blacksburg, Virginia 24061
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Kwak JM, Mäser P, Schroeder JI. The Clickable Guard Cell, Version II: Interactive Model of Guard Cell Signal Transduction Mechanisms and Pathways. THE ARABIDOPSIS BOOK 2008; 6:e0114. [PMID: 22303239 PMCID: PMC3243356 DOI: 10.1199/tab.0114] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Guard cells are located in the leaf epidermis and pairs of guard cells surround and form stomatal pores, which regulate CO(2) influx from the atmosphere into leaves for photosynthetic carbon fixation. Stomatal guard cells also regulate water loss of plants via transpiration to the atmosphere. Signal transduction mechanisms in guard cells integrate a multitude of different stimuli to modulate stomatal apertures. Stomata open in response to light. Stomata close in response to drought stress, elevated CO(2), ozone and low humidity. In response to drought, plants synthesize the hormone abscisic acid (ABA) that triggers closing of stomatal pores. Guard cells have become a highly developed model system for dissecting signal transduction mechanisms in plants and for elucidating how individual signaling mechanisms can interact within a network in a single cell. Many new findings have been made in the last few years. This chapter is an update of an electronic interactive chapter in the previous edition of The Arabidopsis Book (Mäser et al. 2003). Here we focus on mechanisms for which genes and mutations have been characterized, including signaling components for which there is substantial signaling, biochemical and genetic evidence. Ion channels have been shown to represent targets of early signal transduction mechanisms and provide functional signaling and quantitative analysis points to determine where and how mutations affect branches within the guard cell signaling network. Although a substantial number of genes and proteins that function in guard cell signaling have been identified in recent years, there are many more left to be identified and the protein-protein interactions within this network will be an important subject of future research. A fully interactive clickable electronic version of this publication can be accessed at the following web site: http://www-biology.ucsd.edu/labs/schroeder/clickablegc2/. The interactive clickable version includes the following features: Figure 1. Model for the roles of ion channels in ABA signaling.Figure 2. Blue light signaling pathways in guard cells.Figure 3. ABA signaling pathways in guard cells.Figure 1 is linked to explanations that appear upon mouse-over. Figure 2 and Figure 3 are clickable and linked to info boxes, which in turn are linked to TAIR, to relevant abstracts in PubMed, and to updated background explanations from Schroeder et al (2001), used with permission of Annual Reviews of Plant Biology.
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Affiliation(s)
- June M. Kwak
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, Maryland 20742
| | - Pascal Mäser
- Institute of Cell Biology, University of Berne, CH-3012 Bern, Switzerland
| | - Julian I. Schroeder
- Division of Biological Sciences, Cell and Developmental Biology Section and Center for Molecular Genetics, University of California, San Diego, La Jolla, California 92093-0116
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Ercetin ME, Ananieva EA, Safaee NM, Torabinejad J, Robinson JY, Gillaspy GE. A phosphatidylinositol phosphate-specific myo-inositol polyphosphate 5-phosphatase required for seedling growth. PLANT MOLECULAR BIOLOGY 2008; 67:375-88. [PMID: 18392779 DOI: 10.1007/s11103-008-9327-3] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/25/2007] [Accepted: 03/19/2008] [Indexed: 05/19/2023]
Abstract
The phosphatidylinositol phosphate signaling pathway is involved in many crucial cellular functions. The myo-inositol polyphosphate 5-phosphatases (5PTases) (E.C. 3.1.3.56) comprise a large protein family that hydrolyze 5-phosphates from a variety of phosphatidylinositol phosphate and inositol phosphate substrates. We previously reported that the At5PTase11 enzyme (At1g47510), which is one of the smallest predicted 5PTases found in any organism, encodes an active 5PTase whose activity is restricted to tris- and bis-, but not mono-phosphorylated phosphatidylinositol phosphate substrates containing a 5-phosphate. This is in contrast to other unrestricted Arabidopsis 5PTases, which also hydrolyze tris- and bis inositol phosphate molecules. To further explore the function of At5PTase11, we have characterized two T-DNA mutants in the At5PTase11 gene, and have complemented this mutant. Seed from 5ptase11 mutants germinate slower than wildtype seed and mutant seedlings have decreased hypocotyl growth as compared to wildtype seedlings when grown in the dark. This phenotype is the opposite of the increased hypocotyl growth phenotype previously described for other 5ptase mutants defective in inositol phosphate-specific 5PTase enzymes. By labeling the endogenous myo-inositol pool in 5ptase11 mutants, we correlated these hypocotyl growth changes with a small increase in the 5PTase11 substrate, phosphatidylinositol (4,5) bisphosphate, and decreases in the potential products of 5PTase11, phosphatidylinositol (3) phosphate and phosphatidylinositol (4) phosphate. Surprisingly, we also found that dark-grown 5ptase11 mutants contain increases in inositol (1,4,5) trisphosphate and an inositol bisphosphate that is not a substrate for recombinant 5PTase11. We present a model for regulation of hypocotyl growth by specific molecules found in this pathway.
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Affiliation(s)
- Mustafa E Ercetin
- Department of Biochemistry, Virginia Tech, Blacksburg, VA 24061, USA
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