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Wallner ES, Mair A, Handler D, McWhite C, Xu SL, Dolan L, Bergmann DC. Spatially resolved proteomics of the Arabidopsis stomatal lineage identifies polarity complexes for cell divisions and stomatal pores. Dev Cell 2024; 59:1096-1109.e5. [PMID: 38518768 DOI: 10.1016/j.devcel.2024.03.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2023] [Revised: 02/23/2024] [Accepted: 03/05/2024] [Indexed: 03/24/2024]
Abstract
Cell polarity is used to guide asymmetric divisions and create morphologically diverse cells. We find that two oppositely oriented cortical polarity domains present during the asymmetric divisions in the Arabidopsis stomatal lineage are reconfigured into polar domains marking ventral (pore-forming) and outward-facing domains of maturing stomatal guard cells. Proteins that define these opposing polarity domains were used as baits in miniTurboID-based proximity labeling. Among differentially enriched proteins, we find kinases, putative microtubule-interacting proteins, and polar SOSEKIs with their effector ANGUSTIFOLIA. Using AI-facilitated protein structure prediction models, we identify potential protein-protein interaction interfaces among them. Functional and localization analyses of the polarity protein OPL2 and its putative interaction partners suggest a positive interaction with mitotic microtubules and a role in cytokinesis. This combination of proteomics and structural modeling with live-cell imaging provides insights into how polarity is rewired in different cell types and cell-cycle stages.
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Affiliation(s)
- Eva-Sophie Wallner
- Department of Biology, Stanford University, Stanford, CA 94305-5020, USA; Gregor Mendel Institute, Dr. Bohr-Gasse 3, 1030 Wien, Austria; Howard Hughes Medical Institute, Stanford, CA 94305, USA.
| | - Andrea Mair
- Howard Hughes Medical Institute, Stanford, CA 94305, USA
| | | | - Claire McWhite
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544, USA
| | - Shou-Ling Xu
- Carnegie Institution for Science, Stanford, CA 94305, USA; Carnegie Mass Spectrometry Facility, Carnegie Institution for Science, Stanford, CA 94305, USA
| | - Liam Dolan
- Gregor Mendel Institute, Dr. Bohr-Gasse 3, 1030 Wien, Austria
| | - Dominique C Bergmann
- Department of Biology, Stanford University, Stanford, CA 94305-5020, USA; Howard Hughes Medical Institute, Stanford, CA 94305, USA.
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2
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Araniti F, Talarico E, Madeo ML, Greco E, Minervino M, Álvarez-Rodríguez S, Muto A, Ferrari M, Chiappetta A, Bruno L. Short-term exposition to acute Cadmium toxicity induces the loss of root gravitropic stimuli perception through PIN2-mediated auxin redistribution in Arabidopsis thaliana (L.) Heynh. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2023; 332:111726. [PMID: 37149227 DOI: 10.1016/j.plantsci.2023.111726] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2023] [Revised: 03/31/2023] [Accepted: 05/02/2023] [Indexed: 05/08/2023]
Abstract
Cadmium (Cd), one of the most widespread and water-soluble polluting heavy metals, has been widely studied on plants, even if the mechanisms underlying its phytotoxicity remain elusive. Indeed, most experiments are performed using extensive exposure time to the toxicants, not observing the primary targets affected. The present work studied Cd effects on Arabidopsis thaliana (L.) Heynh's root apical meristem (RAM) exposed for short periods (24h and 48h) to acute phytotoxic concentrations (100 and 150µM). The effects were studied through integrated morpho-histological, molecular, pharmacological and metabolomic analyses, highlighting that Cd inhibited primary root elongation by affecting the meristem zone via altering cell expansion. Moreover, Cd altered Auxin accumulation in RAM and affected PINs polar transporters particularly PIN2. In addition, we observed that high Cd concentration induced accumulation of reactive oxygen species (ROS) in roots, which resulted in an altered organization of cortical microtubules and the starch and sucrose metabolism, altering the statolith formation and, consequently, the gravitropic root response. Our results demonstrated that short Cd exposition (24h) affected cell expansion preferentially, altering auxin distribution and inducing ROS accumulation, which resulted in an alteration of gravitropic response and microtubules orientation pattern.
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Affiliation(s)
- Fabrizio Araniti
- Department of Agricultural and Environmental Sciences, University of Milano, Milan 20133, Italy
| | - Emanuela Talarico
- Department of Biology, Ecology and Earth Sciences (DiBEST), University of Calabria, Arcavacata of Rende, CS 87036, Italy
| | - Maria Letizia Madeo
- Department of Biology, Ecology and Earth Sciences (DiBEST), University of Calabria, Arcavacata of Rende, CS 87036, Italy
| | - Eleonora Greco
- Department of Biology, Ecology and Earth Sciences (DiBEST), University of Calabria, Arcavacata of Rende, CS 87036, Italy
| | - Marco Minervino
- Department of Biology, Ecology and Earth Sciences (DiBEST), University of Calabria, Arcavacata of Rende, CS 87036, Italy
| | - Sara Álvarez-Rodríguez
- Universidade de Vigo, Departamento de Bioloxía Vexetal e Ciencias do Solo, Facultade de Bioloxía, Campus Lagoas-Marcosende s/n, 36310, Vigo, Spain
| | - Antonella Muto
- Department of Biology, Ecology and Earth Sciences (DiBEST), University of Calabria, Arcavacata of Rende, CS 87036, Italy
| | - Michele Ferrari
- Department of Biology, Ecology and Earth Sciences (DiBEST), University of Calabria, Arcavacata of Rende, CS 87036, Italy
| | - Adriana Chiappetta
- Department of Biology, Ecology and Earth Sciences (DiBEST), University of Calabria, Arcavacata of Rende, CS 87036, Italy
| | - Leonardo Bruno
- Department of Biology, Ecology and Earth Sciences (DiBEST), University of Calabria, Arcavacata of Rende, CS 87036, Italy.
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Zhu J, Wang WS, Yan DW, Hong LW, Li TT, Gao X, Yang YH, Ren F, Lu YT, Yuan TT. CK2 promotes jasmonic acid signaling response by phosphorylating MYC2 in Arabidopsis. Nucleic Acids Res 2022; 51:619-630. [PMID: 36546827 PMCID: PMC9881174 DOI: 10.1093/nar/gkac1213] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Revised: 10/19/2022] [Accepted: 12/07/2022] [Indexed: 12/24/2022] Open
Abstract
Jasmonic acid (JA) signaling plays a pivotal role in plant development and defense. MYC2 is a master transcription factor in JA signaling, and was found to be phosphorylated and negatively regulated by MAP kinase and receptor-like kinase. However, the kinases that positively regulate MYC2 through phosphorylation and promote MYC2-mediated activation of JA response have not been identified. Here, we identified CK2 as a kinase that phosphorylates MYC2 and thus regulates the JA signaling. CK2 holoenzyme can interact with MYC2 using its regulatory subunits and phosphorylate MYC2 at multiple sites with its catalytic subunits. Inhibition of CK2 activity in a dominant-negative plant line, CK2mut, repressed JA response. On the other hand, increasing CK2 activity by overexpression of CKB4, a regulatory subunit gene of CK2, enhanced JA response in a MYC2-dependent manner. Substitution of the Ser and Thr residues at phosphorylation sites of MYC2 by CK2 with Ala impaired MYC2 function in activating JA response. Further investigations evidenced that CK2 facilitated the JA-induced increase of MYC2 binding to the promoters of JA-responsive genes in vivo. Our study demonstrated that CK2 plays a positive role in JA signaling, and reveals a previously undiscovered mechanism that regulates MYC2 function.
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Affiliation(s)
| | | | - Da-Wei Yan
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Renmin Hospital of Wuhan University, Wuhan University, Wuhan 430072, China
| | - Li-Wei Hong
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Renmin Hospital of Wuhan University, Wuhan University, Wuhan 430072, China
| | - Ting-Ting Li
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Renmin Hospital of Wuhan University, Wuhan University, Wuhan 430072, China
| | - Xiang Gao
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Renmin Hospital of Wuhan University, Wuhan University, Wuhan 430072, China
| | - Yun-Huang Yang
- State Key Laboratory of Magnetic Resonance and Atomic Molecular Physics, National Center for Magnetic Resonance in Wuhan, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan 430071, China
| | - Feng Ren
- Hubei Key Laboratory of Genetic Regulation and Integrative Biology, School of Life Sciences, Central China Normal University, Wuhan 430079, China
| | - Ying-Tang Lu
- Correspondence may also be addressed to Ying-Tang Lu. Tel: +86 27 68752619; Fax: +86 27 68753551;
| | - Ting-Ting Yuan
- To whom correspondence should be addressed. Tel: +86 27 68752619; Fax: +86 27 68753551;
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Zhang Z, Yang W, Chu Y, Yin X, Liang Y, Wang Q, Wang L, Han Z. AtHD2D, a plant-specific histone deacetylase involved in abscisic acid response and lateral root development. JOURNAL OF EXPERIMENTAL BOTANY 2022; 73:7380-7400. [PMID: 36125085 DOI: 10.1093/jxb/erac381] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2022] [Accepted: 09/18/2022] [Indexed: 06/15/2023]
Abstract
In eukaryotes, histone acetylation levels directly regulate downstream gene expression. As a plant-specific histone deacetylase (HDAC), HD2D is involved in plant development and abiotic stress. However, the response of HD2D to drought stress and its interacting proteins, is still unclear. In this study, we analysed HD2D gene expression patterns in Arabidopsis, revealing that HD2D gene was highly expressed in roots and rosette leaves, but poorly expressed in other tissues such as stems, flowers, and young siliques. The HD2D gene expression was induced by d-mannitol. We investigated the responses to drought stress in the wild-type plant, HD2D overexpression lines, and hd2d mutants. HD2D-overexpressing lines showed abscisic acid (ABA) hypersensitivity and drought tolerance, and these phenotypes were not present in hd2d mutants. RNA-seq analysis revealed the transcriptome changes caused by HD2D under drought stress, and showed that HD2D responded to drought stress via the ABA signalling pathway. In addition, we demonstrated that CASEIN KINASE II (CKA4) directly interacted with HD2D. The phosphorylation of Ser residues on HD2D by CKA4 enhanced HD2D enzymatic activity. Furthermore, the phosphorylation of HD2D was shown to contribute to lateral root development and ABA sensing in Arabidopsis, but, these phenotypes could not be reproduced by the overexpression of Ser-phospho-null HD2D lines. Collectively, this study suggests that HD2D responded to drought stress by regulating the ABA signalling pathway, and the expression of drought stress-related genes. The regulatory mechanism of HD2D mediated by CKII phosphorylation provides new insights into the ABA response and lateral root development in Arabidopsis.
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Affiliation(s)
- Zhaochen Zhang
- College of Life Science, Northwest A & F University, Yangling, Shanxi 712100, China
| | - Weixia Yang
- College of Chemistry & Pharmacy, Northwest A & F University, Yangling, Shanxi 712100, China
| | - Yueyang Chu
- College of Life Science, Northwest A & F University, Yangling, Shanxi 712100, China
| | - Xiaotong Yin
- College of Life Science, Northwest A & F University, Yangling, Shanxi 712100, China
| | - Yueqi Liang
- College of Innovation and Experiment, Northwest A & F University, Yangling, Shanxi 712100, China
| | - Qiuping Wang
- College of Life Science, Northwest A & F University, Yangling, Shanxi 712100, China
| | - Lei Wang
- College of Life Science, Northwest A & F University, Yangling, Shanxi 712100, China
| | - Zhaofen Han
- College of Life Science, Northwest A & F University, Yangling, Shanxi 712100, China
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5
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Wang G, Gao G, Yang X, Yang X, Ma P. Casein kinase CK2 structure and activities in plants. JOURNAL OF PLANT PHYSIOLOGY 2022; 276:153767. [PMID: 35841742 DOI: 10.1016/j.jplph.2022.153767] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Revised: 07/10/2022] [Accepted: 07/10/2022] [Indexed: 06/15/2023]
Abstract
Casein kinase CK2 is a highly conserved serine/threonine protein kinase and exists in all eukaryotes. It has been demonstrated to be widely involved in the biological processes of plants. The CK2 holoenzyme is a heterotetramer consisting of two catalytic subunits (α and/or α') and two regulatory subunits (β). CK2 in plants is generally encoded by multiple genes, with monomeric and oligomeric forms present in the tissue. Various subunit genes of CK2 have been cloned and characterized from Arabidopsis thaliana, tobacco, maize, wheat, tomato, and other plants. This paper reviews the structural features of CK2, provides a clear classification of its physiological functions and mechanisms of action, and elaborates on the regulation of CK2 activity to provide a knowledge base for subsequent studies of CK2 in plants.
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Affiliation(s)
- Guanfeng Wang
- College of Life Sciences, Northwest A&F University, Yangling, 712100, China
| | - Geling Gao
- College of Life Sciences, Northwest A&F University, Yangling, 712100, China
| | - Xiangna Yang
- College of Life Sciences, Northwest A&F University, Yangling, 712100, China
| | - Xiangdong Yang
- Institute of Agricultural Biotechnology, Jilin Academy of Agricultural Sciences, Changchun, 130033, China.
| | - Pengda Ma
- College of Life Sciences, Northwest A&F University, Yangling, 712100, China.
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6
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Zhuang X, Guo X, Gu T, Xu X, Qin L, Xu K, He Z, Zhang K. Phosphorylation of plant virus proteins: Analysis methods and biological functions. Front Microbiol 2022; 13:935735. [PMID: 35958157 PMCID: PMC9360750 DOI: 10.3389/fmicb.2022.935735] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2022] [Accepted: 06/28/2022] [Indexed: 11/13/2022] Open
Abstract
Phosphorylation is one of the most extensively investigated post-translational modifications that orchestrate a variety of cellular signal transduction processes. The phosphorylation of virus-encoded proteins plays an important regulatory role in the infection cycle of such viruses in plants. In recent years, molecular mechanisms underlying the phosphorylation of plant viral proteins have been widely studied. Based on recent publications, our study summarizes the phosphorylation analyses of plant viral proteins and categorizes their effects on biological functions according to the viral life cycle. This review provides a theoretical basis for elucidating the molecular mechanisms of viral infection. Furthermore, it deepens our understanding of the biological functions of phosphorylation in the interactions between plants and viruses.
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Affiliation(s)
- Xinjian Zhuang
- Department of Plant Protection, College of Horticulture and Plant Protection, Yangzhou University, Yangzhou, China
| | - Xiao Guo
- Department of Plant Protection, College of Horticulture and Plant Protection, Yangzhou University, Yangzhou, China
| | - Tianxiao Gu
- Department of Plant Protection, College of Horticulture and Plant Protection, Yangzhou University, Yangzhou, China
| | - Xiaowei Xu
- Department of Plant Protection, College of Horticulture and Plant Protection, Yangzhou University, Yangzhou, China
| | - Lang Qin
- Department of Plant Protection, College of Horticulture and Plant Protection, Yangzhou University, Yangzhou, China
| | - Kai Xu
- Jiangsu Key Laboratory for Microbes and Functional Genomics, Jiangsu Engineering and Technology Research Center for Microbiology, College of Life Sciences, Nanjing Normal University, Nanjing, China
| | - Zhen He
- Department of Plant Protection, College of Horticulture and Plant Protection, Yangzhou University, Yangzhou, China
| | - Kun Zhang
- Department of Plant Protection, College of Horticulture and Plant Protection, Yangzhou University, Yangzhou, China,Jiangsu Key Laboratory for Microbes and Functional Genomics, Jiangsu Engineering and Technology Research Center for Microbiology, College of Life Sciences, Nanjing Normal University, Nanjing, China,*Correspondence: Kun Zhang, ;
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7
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Sun Z, Li Q, Li X, Shi Y, Nan C, Jin Q, Wang X, Zhuo Y, Zhao Z. Casein kinase 2 attenuates brain injury induced by intracerebral hemorrhage via regulation of NR2B phosphorylation. Front Cell Neurosci 2022; 16:911973. [PMID: 35928572 PMCID: PMC9345180 DOI: 10.3389/fncel.2022.911973] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2022] [Accepted: 06/27/2022] [Indexed: 11/16/2022] Open
Abstract
Objective Intracerebral hemorrhage (ICH) is a common cerebrovascular disease with high incidence, disability, and mortality. Casein kinase 2 (CK2) is a serine/threonine kinase with hundreds of identified substrates and plays an important role in many diseases. This study aimed to explore whether CK2 plays protective roles in ICH-induced neuronal apoptosis, inflammation, and oxidative stress through regulation NR2B phosphorylation. Methods CK2 expression level of brain tissues taken from ICH patients was determined by immunoblotting. Neurons from embryonic rat and astrocytes from newborn rats were cultured and treated by Hemoglobin chloride (Hemin). The proliferation of astrocytes, the apoptosis and oxidative stress of neurons and the inflammatory factors of astrocytes were detected. CK2 expression was determined in ICH model rats. The effects of CK2 overexpression plasmid (pc-CK2) on neurobehavioral defects and brain water content in ICH rats were observed. Results CK2 expression in ICH patients was down-regulated. Overexpression of CK2 promoted the astrocyte proliferation, inhibited neuronal apoptosis, and reduced astrocyte-mediated inflammation. N-methyl-D-aspartate receptor 2B (NR2B) reversed the effects of pc-CK2 on neurons and astrocytes. CK2 phosphorylated NR2B at the S1480 site, down-regulated the expression of NR2B and interfered with the interaction between NR2B and postsynaptic density protein 95 (PSD95). In vivo experiments showed that the expression of CK2 decreased and the expression of NR2B increased in ICH rats. Furthermore, pc-CK2 attenuated neurobehavioral defects, brain water content and neuronal damage in ICH rats. Conclusion CK2 phosphorylated NR2B, down-regulated the expression of NR2B, interfered with the interaction between NR2B and PSD95, alleviated inflammatory reactions, inhibited neuronal apoptosis and oxidative stress after ICH. CK2 and NR2B may be new potential therapeutic targets for the treatment of ICH. However, the limitation of this study is that we only investigated the regulation of NR2B by CK2.
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Affiliation(s)
- Zhimin Sun
- Department of Neurosurgery, The Second Hospital of Hebei Medical University, Shijiazhuang, China
- Department of Neurosurgery, The Third Hospital of Shijiazhuang City, Shijiazhuang, China
| | - Qiyao Li
- Department of Neurosurgery, The Second Hospital of Hebei Medical University, Shijiazhuang, China
| | - Xiaopeng Li
- Department of Neurosurgery, The Second Hospital of Hebei Medical University, Shijiazhuang, China
- Department of Neurosurgery, The First Hospital of Handan City, Handan, China
| | - Yunpeng Shi
- Department of Neurosurgery, The Second Hospital of Hebei Medical University, Shijiazhuang, China
| | - Chengrui Nan
- Department of Neurosurgery, The Second Hospital of Hebei Medical University, Shijiazhuang, China
| | - Qianxu Jin
- Department of Neurosurgery, The Second Hospital of Hebei Medical University, Shijiazhuang, China
| | - Xiaoyan Wang
- Department of Neurosurgery, The Second Hospital of Hebei Medical University, Shijiazhuang, China
- Department of Neurosurgery, Hebei General Hospital, Shijiazhuang, China
| | - Yayu Zhuo
- Department of Neurosurgery, The Second Hospital of Hebei Medical University, Shijiazhuang, China
| | - Zongmao Zhao
- Department of Neurosurgery, The Second Hospital of Hebei Medical University, Shijiazhuang, China
- *Correspondence: Zongmao Zhao,
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Wang GL, Zhang CL, Huo HQ, Sun XS, Zhang YL, Hao YJ, You CX. The SUMO E3 Ligase MdSIZ1 Sumoylates a Cell Number Regulator MdCNR8 to Control Organ Size. FRONTIERS IN PLANT SCIENCE 2022; 13:836935. [PMID: 35498700 PMCID: PMC9051543 DOI: 10.3389/fpls.2022.836935] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Accepted: 03/14/2022] [Indexed: 06/01/2023]
Abstract
Plant growth and organ size putatively associated with crop yield are regulated by a complex network of genes including ones for controlling cell proliferation. The gene fw2.2 was first identified in tomatoes and reported to govern fruit size variation through controlling cell division. In this study, we isolated a putative ortholog of the tomato fw2.2 gene from apple, Cell Number Regulator 8 (MdCNR8). Our functional analysis showed that MdCNR8 may control fruit size and root growth. MdCNR8 was mediated by the SUMO E3 ligase MdSIZ1, and SUMOylation of MdCNR8 at residue-Lys39 promoted the translocation of MdCNR8 from plasma membrane to the nucleus. The effect of MdCNR8 in inhibiting root elongation could be completely counteracted by the coexpression of MdSIZ1. Moreover, the lower cell proliferation of apple calli due to silencing MdSIZ1 could be rescued by silencing MdCNR8. Collectively, our results showed that the MdSIZ1-mediated SUMOylation is required for the fulfillment of MdCNR8 in regulating cell proliferation to control plant organ size. This regulatory interaction between MdSIZ1 and MdCNR8 will facilitate understanding the mechanism underlying the regulation of organ size.
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Affiliation(s)
- Gui-Luan Wang
- State Key Laboratory of Crop Biology, College of Horticulture Science and Engineering, Shandong Agricultural University, Taian, Shandong, China
| | - Chun-Ling Zhang
- State Key Laboratory of Crop Biology, College of Horticulture Science and Engineering, Shandong Agricultural University, Taian, Shandong, China
| | - He-Qiang Huo
- Mid-Florida Research and Education Center, University of Florida, Institute of Food and Agricultural Sciences, Apopka, FL, United States
| | | | - Ya-Li Zhang
- State Key Laboratory of Crop Biology, College of Horticulture Science and Engineering, Shandong Agricultural University, Taian, Shandong, China
| | - Yu-Jin Hao
- State Key Laboratory of Crop Biology, College of Horticulture Science and Engineering, Shandong Agricultural University, Taian, Shandong, China
| | - Chun-Xiang You
- State Key Laboratory of Crop Biology, College of Horticulture Science and Engineering, Shandong Agricultural University, Taian, Shandong, China
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Leonardo B, Emanuela T, Letizia MM, Antonella M, Marco M, Fabrizio A, Beatrice BM, Adriana C. Cadmium affects cell niches maintenance in Arabidopsis thaliana post-embryonic shoot and root apical meristem by altering the expression of WUS/WOX homolog genes and cytokinin accumulation. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2021; 167:785-794. [PMID: 34530323 DOI: 10.1016/j.plaphy.2021.09.014] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2021] [Revised: 09/08/2021] [Accepted: 09/09/2021] [Indexed: 06/13/2023]
Abstract
Cadmium (Cd) is one of the most widespread polluting heavy metals in both terrestrial and aquatic environments and represents an extremely significant pollutant causing severe environmental and social problems due to its high toxicity and large solubility in water. In plants, the root is the first organ that get in contact with Cd. It is absorbed by the root system and translocated to the shoot and leaves through xylem loading, causing a variety of genetic, biochemical, and physiological damages. Cd inhibits both the root and shoot growth, but the mechanisms underlying this inhibition remain elusive. In this context in the present work we focused the attention on the effects of Cd on meristem size and organization of both shoot and root. To this aim morpho-histological and molecular analyses were carried out on 5 days old seedlings exposed or not to Cd (100 μM and 150 μM for 24) of wild type and transgenic lines expressing molecular markers with an important role in shoot and root pattern organization. More precisely, we monitored the expression pattern of WUS/CLV3 and WOX5 transcription factors involved in the establishment and maintenance of stem cell niche and the control of meristem size and of TCSn::GFP cytokinin-sensitive sensor as relevant components of hormone circuit controlling shoot and root growth. The results highlighted that the treatments with Cd impacts shoot and root size and shape by altering the paralogous WOX genes expression via cytokinin accumulation.
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Affiliation(s)
- Bruno Leonardo
- Dipartimento di Biologia, Ecologia e Scienza della Terra, Università della Calabria (DiBEST-UNICAL), Arcavacata di Rende, Italy.
| | - Talarico Emanuela
- Dipartimento di Biologia, Ecologia e Scienza della Terra, Università della Calabria (DiBEST-UNICAL), Arcavacata di Rende, Italy
| | - Madeo Maria Letizia
- Dipartimento di Biologia, Ecologia e Scienza della Terra, Università della Calabria (DiBEST-UNICAL), Arcavacata di Rende, Italy
| | - Muto Antonella
- Dipartimento di Biologia, Ecologia e Scienza della Terra, Università della Calabria (DiBEST-UNICAL), Arcavacata di Rende, Italy
| | - Minervino Marco
- Dipartimento di Biologia, Ecologia e Scienza della Terra, Università della Calabria (DiBEST-UNICAL), Arcavacata di Rende, Italy
| | - Araniti Fabrizio
- Dipartimento di Scienze Agrarie e Ambientali - Produzione, Territorio, Agroenergia, Università Statale di Milano, Via Celoria n°2, 20133, Milano, Italy
| | - Bitonti Maria Beatrice
- Dipartimento di Biologia, Ecologia e Scienza della Terra, Università della Calabria (DiBEST-UNICAL), Arcavacata di Rende, Italy
| | - Chiappetta Adriana
- Dipartimento di Biologia, Ecologia e Scienza della Terra, Università della Calabria (DiBEST-UNICAL), Arcavacata di Rende, Italy
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10
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Bruno L, Talarico E, Cabeiras-Freijanes L, Madeo ML, Muto A, Minervino M, Lucini L, Miras-Moreno B, Sofo A, Araniti F. Coumarin Interferes with Polar Auxin Transport Altering Microtubule Cortical Array Organization in Arabidopsis thaliana (L.) Heynh. Root Apical Meristem. Int J Mol Sci 2021; 22:ijms22147305. [PMID: 34298924 PMCID: PMC8306912 DOI: 10.3390/ijms22147305] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2021] [Revised: 07/04/2021] [Accepted: 07/05/2021] [Indexed: 01/22/2023] Open
Abstract
Coumarin is a phytotoxic natural compound able to affect plant growth and development. Previous studies have demonstrated that this molecule at low concentrations (100 µM) can reduce primary root growth and stimulate lateral root formation, suggesting an auxin-like activity. In the present study, we evaluated coumarin’s effects (used at lateral root-stimulating concentrations) on the root apical meristem and polar auxin transport to identify its potential mode of action through a confocal microscopy approach. To achieve this goal, we used several Arabidopsis thaliana GFP transgenic lines (for polar auxin transport evaluation), immunolabeling techniques (for imaging cortical microtubules), and GC-MS analysis (for auxin quantification). The results highlighted that coumarin induced cyclin B accumulation, which altered the microtubule cortical array organization and, consequently, the root apical meristem architecture. Such alterations reduced the basipetal transport of auxin to the apical root apical meristem, inducing its accumulation in the maturation zone and stimulating lateral root formation.
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Affiliation(s)
- Leonardo Bruno
- Dipartimento di Biologia, Ecologia e Scienza della Terra, Università della Calabria (DiBEST-UNICAL), 87036 Arcavacata di Rende, Italy; (E.T.); (M.L.M.); (A.M.); (M.M.)
- Correspondence: (L.B.); (F.A.)
| | - Emanuela Talarico
- Dipartimento di Biologia, Ecologia e Scienza della Terra, Università della Calabria (DiBEST-UNICAL), 87036 Arcavacata di Rende, Italy; (E.T.); (M.L.M.); (A.M.); (M.M.)
| | - Luz Cabeiras-Freijanes
- Department of Plant Biology and Soil Science, Campus Lagoas-Marcosende, University of Vigo, 36310 Vigo, Spain;
- CITACA, Agri-Food Research and Transfer Cluster, Campus da Auga, University of Vigo, 32004 Ourense, Spain
| | - Maria Letizia Madeo
- Dipartimento di Biologia, Ecologia e Scienza della Terra, Università della Calabria (DiBEST-UNICAL), 87036 Arcavacata di Rende, Italy; (E.T.); (M.L.M.); (A.M.); (M.M.)
| | - Antonella Muto
- Dipartimento di Biologia, Ecologia e Scienza della Terra, Università della Calabria (DiBEST-UNICAL), 87036 Arcavacata di Rende, Italy; (E.T.); (M.L.M.); (A.M.); (M.M.)
| | - Marco Minervino
- Dipartimento di Biologia, Ecologia e Scienza della Terra, Università della Calabria (DiBEST-UNICAL), 87036 Arcavacata di Rende, Italy; (E.T.); (M.L.M.); (A.M.); (M.M.)
| | - Luigi Lucini
- Department for Sustainable Food Process, Università Cattolica del Sacro Cuore, Via Emilia Parmense 84, 29122 Piacenza, Italy; (L.L.); (B.M.-M.)
| | - Begoña Miras-Moreno
- Department for Sustainable Food Process, Università Cattolica del Sacro Cuore, Via Emilia Parmense 84, 29122 Piacenza, Italy; (L.L.); (B.M.-M.)
| | - Adriano Sofo
- Department of European and Mediterranean Cultures: Architecture, Environment, and Cultural Heritage (DICEM), University of Basilicata, 75100 Matera, Italy;
| | - Fabrizio Araniti
- Dipartimento di Scienze Agrarie e Ambientali—Produzione, Territorio, Agroenergia, Università Statale di Milano, Via Celoria n°2, 20133 Milano, Italy
- Correspondence: (L.B.); (F.A.)
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11
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Qin X, Li P, Lu S, Sun Y, Meng L, Hao J, Fan S. Phosphoproteomic analysis of lettuce (Lactuca sativa L.) reveals starch and sucrose metabolism functions during bolting induced by high temperature. PLoS One 2020; 15:e0244198. [PMID: 33373388 PMCID: PMC7771692 DOI: 10.1371/journal.pone.0244198] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Accepted: 12/05/2020] [Indexed: 01/07/2023] Open
Abstract
High temperatures induce early bolting in lettuce (Lactuca sativa L.), which decreases both quality and production. However, knowledge of the molecular mechanism underlying high temperature promotes premature bolting is lacking. In this study, we compared lettuce during the bolting period induced by high temperatures (33/25 °C, day/night) to which raised under controlled temperatures (20/13 °C, day/night) using iTRAQ-based phosphoproteomic analysis. A total of 3,814 phosphorylation sites located on 1,766 phosphopeptides from 987 phosphoproteins were identified after high-temperature treatment,among which 217 phosphoproteins significantly changed their expression abundance (116 upregulated and 101 downregulated). Most phosphoproteins for which the abundance was altered were associated with the metabolic process, with the main molecular functions were catalytic activity and transporter activity. Regarding the functional pathway, starch and sucrose metabolism was the mainly enriched signaling pathways. Hence, high temperature influenced phosphoprotein activity, especially that associated with starch and sucrose metabolism. We suspected that the lettuce shorten its growth cycle and reduce vegetative growth owing to changes in the contents of starch and soluble sugar after high temperature stress, which then led to early bolting/flowering. These findings improve our understanding of the regulatory molecular mechanisms involved in lettuce bolting.
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Affiliation(s)
- Xiaoxiao Qin
- Beijing Key Laboratory of New Technology in Agricultural Application, National Demonstration Center for Experimental Plant Production Education, Plant Science and Technology College, Beijing University of Agriculture, Beijing, China
| | - Panpan Li
- Beijing Key Laboratory of New Technology in Agricultural Application, National Demonstration Center for Experimental Plant Production Education, Plant Science and Technology College, Beijing University of Agriculture, Beijing, China
| | - Shaowei Lu
- Facility Horticulture Institute, Ministry of Agriculture Planning and Design Research Academy, Beijing, China
| | - Yanchuan Sun
- Beijing Key Laboratory of New Technology in Agricultural Application, National Demonstration Center for Experimental Plant Production Education, Plant Science and Technology College, Beijing University of Agriculture, Beijing, China
| | - Lifeng Meng
- Institute of Apicultural Research/Key Laboratory of Pollinating Insect Biology, Ministry of Agriculture, Chinese Academy of Agricultural Science, Beijing, China
| | - Jinghong Hao
- Beijing Key Laboratory of New Technology in Agricultural Application, National Demonstration Center for Experimental Plant Production Education, Plant Science and Technology College, Beijing University of Agriculture, Beijing, China
| | - Shuangxi Fan
- Beijing Key Laboratory of New Technology in Agricultural Application, National Demonstration Center for Experimental Plant Production Education, Plant Science and Technology College, Beijing University of Agriculture, Beijing, China
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12
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Kamal MM, Ishikawa S, Takahashi F, Suzuki K, Kamo M, Umezawa T, Shinozaki K, Kawamura Y, Uemura M. Large-Scale Phosphoproteomic Study of Arabidopsis Membrane Proteins Reveals Early Signaling Events in Response to Cold. Int J Mol Sci 2020; 21:E8631. [PMID: 33207747 PMCID: PMC7696906 DOI: 10.3390/ijms21228631] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Revised: 11/12/2020] [Accepted: 11/13/2020] [Indexed: 12/22/2022] Open
Abstract
Cold stress is one of the major factors limiting global crop production. For survival at low temperatures, plants need to sense temperature changes in the surrounding environment. How plants sense and respond to the earliest drop in temperature is still not clearly understood. The plasma membrane and its adjacent extracellular and cytoplasmic sites are the first checkpoints for sensing temperature changes and the subsequent events, such as signal generation and solute transport. To understand how plants respond to early cold exposure, we used a mass spectrometry-based phosphoproteomic method to study the temporal changes in protein phosphorylation events in Arabidopsis membranes during 5 to 60 min of cold exposure. The results revealed that brief cold exposures led to rapid phosphorylation changes in the proteins involved in cellular ion homeostasis, solute and protein transport, cytoskeleton organization, vesical trafficking, protein modification, and signal transduction processes. The phosphorylation motif and kinase-substrate network analysis also revealed that multiple protein kinases, including RLKs, MAPKs, CDPKs, and their substrates, could be involved in early cold signaling. Taken together, our results provide a first look at the cold-responsive phosphoproteome changes of Arabidopsis membrane proteins that can be a significant resource to understand how plants respond to an early temperature drop.
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Affiliation(s)
- Md Mostafa Kamal
- United Graduate School of Agricultural Sciences, Iwate University, Morioka 020-8550, Japan; (M.M.K.); (Y.K.)
| | - Shinnosuke Ishikawa
- Graduate School of Bio-Applications and Systems Engineering, Tokyo University of Agriculture and Technology, Koganei 184-8588, Japan; (S.I.); (T.U.)
| | - Fuminori Takahashi
- Gene Discovery Research Group, RIKEN Center for Sustainable Resource Science, 3-1-1 Koyadai, Tsukuba 305-0074, Japan; (F.T.); (K.S.)
| | - Ko Suzuki
- Department of Biochemistry, Iwate Medical University, Yahaba 028-3694, Japan; (K.S.); (M.K.)
| | - Masaharu Kamo
- Department of Biochemistry, Iwate Medical University, Yahaba 028-3694, Japan; (K.S.); (M.K.)
| | - Taishi Umezawa
- Graduate School of Bio-Applications and Systems Engineering, Tokyo University of Agriculture and Technology, Koganei 184-8588, Japan; (S.I.); (T.U.)
| | - Kazuo Shinozaki
- Gene Discovery Research Group, RIKEN Center for Sustainable Resource Science, 3-1-1 Koyadai, Tsukuba 305-0074, Japan; (F.T.); (K.S.)
| | - Yukio Kawamura
- United Graduate School of Agricultural Sciences, Iwate University, Morioka 020-8550, Japan; (M.M.K.); (Y.K.)
- Department of Plant-Bioscience, Faculty of Agriculture, Iwate University, Morioka 020-8550, Japan
| | - Matsuo Uemura
- United Graduate School of Agricultural Sciences, Iwate University, Morioka 020-8550, Japan; (M.M.K.); (Y.K.)
- Department of Plant-Bioscience, Faculty of Agriculture, Iwate University, Morioka 020-8550, Japan
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13
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Zhang L, Li Z, Garraway J, Cai Q, Zhou Y, Li X, Hu Z, Zhang M, Yang J. The casein kinase 2 β subunit CK2B1 is required for swollen stem formation via cell cycle control in vegetable Brassica juncea. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2020; 104:706-717. [PMID: 32772441 DOI: 10.1111/tpj.14958] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2020] [Revised: 07/08/2020] [Accepted: 07/21/2020] [Indexed: 06/11/2023]
Abstract
The swollen stem is a determinant of yield for the stem-type vegetable Brassica juncea that is representative of vegetative organ formation. However, the genetic mechanism underlying swollen stem formation and its regulation remains unknown. In this study, we identified a casein kinase 2 β subunit 1 (CK2B1) and revealed its role in swollen stem formation. Genotyping analysis revealed that a homozygous variation in the CK2B1 promoter is responsible for swollen stem formation, and the promoter activity of CK2B1 was significantly associated with the variations between swollen stem and non-swollen stem types. CK2B1 was exclusively located in the nucleus and expressed in the stem nodes of the plant. Swollen stem formation was blocked when CK2B1 expression was silenced, and induced in a backcross population carrying a swollen stem genotype, which indicates that CK2B1 is required for swollen stem formation. Cell numbers were increased during swollen stem formation and decreased in CK2B1-silenced expression plant, indicating that CK2B1 regulates swollen stem formation via cell division. CK2B1 directly interacted with E2Fa, a regulator of G1/S transition in the cell cycle, in which CK2 phosphorylates E2Fa. Our results revealed that CK2B1 affects swollen stem formation via the control of the cell cycle. These findings help to elucidate the signals that control swollen stem formation and provide a promising molecular target to enhance the yield of vegetative organ formation.
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Affiliation(s)
- Lili Zhang
- Laboratory of Germplasm Innovation and Molecular Breeding, Institute of Vegetable Science, Zhejiang University, Hangzhou, 310058, China
| | - Zhangping Li
- Laboratory of Germplasm Innovation and Molecular Breeding, Institute of Vegetable Science, Zhejiang University, Hangzhou, 310058, China
| | - Jenella Garraway
- Laboratory of Germplasm Innovation and Molecular Breeding, Institute of Vegetable Science, Zhejiang University, Hangzhou, 310058, China
| | - Qingze Cai
- Laboratory of Germplasm Innovation and Molecular Breeding, Institute of Vegetable Science, Zhejiang University, Hangzhou, 310058, China
| | - Yufeng Zhou
- Laboratory of Germplasm Innovation and Molecular Breeding, Institute of Vegetable Science, Zhejiang University, Hangzhou, 310058, China
| | - Xiang Li
- Laboratory of Germplasm Innovation and Molecular Breeding, Institute of Vegetable Science, Zhejiang University, Hangzhou, 310058, China
| | - Zhongyuan Hu
- Laboratory of Germplasm Innovation and Molecular Breeding, Institute of Vegetable Science, Zhejiang University, Hangzhou, 310058, China
| | - Mingfang Zhang
- Laboratory of Germplasm Innovation and Molecular Breeding, Institute of Vegetable Science, Zhejiang University, Hangzhou, 310058, China
- Key Laboratory of Horticultural Plant Growth and Development, Ministry of Agriculture and Rural Affairs, Hangzhou, 310058, China
| | - Jinghua Yang
- Laboratory of Germplasm Innovation and Molecular Breeding, Institute of Vegetable Science, Zhejiang University, Hangzhou, 310058, China
- Key Laboratory of Horticultural Plant Growth and Development, Ministry of Agriculture and Rural Affairs, Hangzhou, 310058, China
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14
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Zhang C, Li H, Yuan C, Liu S, Li M, Zhu J, Lin X, Lu Y, Guo X. CKB1 regulates expression of ribosomal protein L10 family gene and plays a role in UV-B response. PLANT BIOLOGY (STUTTGART, GERMANY) 2020; 22 Suppl 1:143-152. [PMID: 30597713 DOI: 10.1111/plb.12954] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2018] [Accepted: 12/22/2018] [Indexed: 06/09/2023]
Abstract
Plastid casein kinase 2 (CK2), which is a major Ser/Thr-specific enzyme in higher organisms, plays an essential role in plant development and diverse abiotic stresses. CKB1 is a regulatory subunit beta of CK2. To expand our understand of functions of the CKB1 gene in Arabidopsis thaliana, protein changes among wild-type (WT) and CKB1 gain- and loss-of-function mutants were compared. Proteins extracted from the CKB1 knockout mutant and overexpressing mutant were compared with Col-0 plants using 2D-PAGE. Proteins regulated by CKB1 were identified with matrix-assisted laser desorption ionisation time-of-flight/time-of-flight mass spectrometry (MALDI-TOF/TOF), and its transcript was verified by qRT-PCR. Bioinformatics analysis, including gene ontology and protein-protein interaction analysis, were employed. The results of mass spectra and bioinformatics analysis suggest that CKB1 may have functions in regulation of the ribosomal protein L10 (RPL10) family and is involved in ultraviolet-B (UV-B) response. Furthermore, qRT-PCR verification showed CKB1 expression was up-regulated by UV-B stress. The expression levels of five genes in the RPL10 family were reduced in the ckb1 T-DNA insertion mutants, whereas they increased in the CKB1 overexpressing mutants under both normal conditions and UV-B treatment. In conclusion, CKB1 has important functions in UV-B radiation stress. Our study implies that CKB1 positively regulates UV-B radiation stress signalling, possibly through modulating expression of the RPL10 family.
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Affiliation(s)
- C Zhang
- College of Life Sciences, Hunan University, Changsha, China
| | - H Li
- College of Life Sciences, Hunan University, Changsha, China
| | - C Yuan
- College of Life Sciences, Hunan University, Changsha, China
| | - S Liu
- College of Life Sciences, Hunan University, Changsha, China
| | - M Li
- College of Life Sciences, Hunan University, Changsha, China
| | - J Zhu
- College of Life Sciences, Hunan University, Changsha, China
| | - X Lin
- College of Life Sciences, Hunan University, Changsha, China
| | - Y Lu
- College of Life Sciences, Hunan University, Changsha, China
| | - X Guo
- College of Life Sciences, Hunan University, Changsha, China
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15
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Phosphorylation of p23-1 cochaperone by protein kinase CK2 affects root development in Arabidopsis. Sci Rep 2019; 9:9846. [PMID: 31285503 PMCID: PMC6614504 DOI: 10.1038/s41598-019-46327-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2019] [Accepted: 06/25/2019] [Indexed: 12/27/2022] Open
Abstract
Root growth is a fundamental process in plants and assures nutrient and water uptake required for efficient photosynthesis and metabolism. Postembryonic development of roots is controlled by the functionality of the meristem. Several hormones and signaling molecules regulate the size of the meristem, and among them, auxins play a major role. Protein kinase CK2, along with the chaperone protein HSP90, has been found to be involved in the regulation of auxin transport. Here, we show that p23-1, a cochaperone of HSP90, is phosphorylated by CK2 in Arabidopsis. We identified Ser201 as the major CK2 target site in p23-1 and demonstrated that phosphorylation of this site is necessary for normal root development. Moreover, we shed light on the nature of CK2 in Arabidopsis, showing that the three catalytic isoforms, CK2 αA, αB and αC, are proteins of approximately 40 kDa. Our results increase knowledge of the connection among HSP90, p23-1 and CK2 in Arabidopsis, suggesting the existence of a possible common root development mechanism controlled by these signaling molecules.
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16
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Genome-wide systematic characterization of bZIP transcription factors and their expression profiles during seed development and in response to salt stress in peanut. BMC Genomics 2019; 20:51. [PMID: 30651065 PMCID: PMC6335788 DOI: 10.1186/s12864-019-5434-6] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2018] [Accepted: 01/07/2019] [Indexed: 12/17/2022] Open
Abstract
BACKGROUND Plant basic leucine zipper (bZIP) transcription factors play crucial roles in plant growth, development, and abiotic stress responses. However, systematic investigation and analyses of the bZIP gene family in peanut are lacking in spite of the availability of the peanut genome sequence. RESULTS In this study, we identified 50 and 45 bZIP genes from Arachis duranensis and A. ipaensis genomes, respectively. Phylogenetic analysis showed that Arachis bZIP genes were classified into nine groups, and these clusters were supported by several group-specific features, including exon/intron structure, intron phases, MEME motifs, and predicted binding site structure. We also identified possible variations in DNA-binding-site specificity and dimerization properties among different Arachis bZIPs by inspecting the amino acid residues at some key sites. Our analysis of the evolutionary history analysis indicated that segmental duplication, rather than tandem duplication, contributed greatly to the expansion of this gene family, and that most Arachis bZIPs underwent strong purifying selection. Through RNA-seq and quantitative real-time PCR (qRT-PCR) analyses, the co-expressed, differentially expressed and several well-studied homologous bZIPs were identified during seed development stages in peanut. We also used qRT-PCR to explore changes in bZIP gene expression in response to salt-treatment, and many candidate bZIPs in groups A, B, and S were proven to be associated with the salt-stress response. CONCLUSIONS This study have conducted a genome-wide identification, characterization and expression analysis of bZIP genes in Arachis genomes. Our results provide insights into the evolutionary history of the bZIP gene family in peanut and the funcntion of Arachis bZIP genes during seed development and in response to salt stress.
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17
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Armengot L, Caldarella E, Marquès-Bueno MM, Martínez MC. The Protein Kinase CK2 Mediates Cross-Talk between Auxin- and Salicylic Acid-Signaling Pathways in the Regulation of PINOID Transcription. PLoS One 2016; 11:e0157168. [PMID: 27275924 PMCID: PMC4898841 DOI: 10.1371/journal.pone.0157168] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2016] [Accepted: 05/25/2016] [Indexed: 01/08/2023] Open
Abstract
The protein kinase CK2 is a ubiquitous and highly conserved enzyme, the activity of which is vital for eukaryotic cells. We recently demonstrated that CK2 modulates salicylic acid (SA) homeostasis in Arabidopsis thaliana, and that functional interplay between CK2 and SA sustains transcriptional expression of PIN-FORMED (PIN) genes. In this work, we show that CK2 also plays a key role in the transcriptional regulation of PINOID (PID), an AGC protein kinase that modulates the apical/basal localization of auxin-efflux transporters. We show that PID transcription is up-regulated by auxin and by SA and that CK2 is involved in both pathways. On the one hand, CK2 activity is required for proteosome-dependent degradation of AXR3, a member of the AUX/IAA family of auxin transcriptional repressors that must be degraded to activate auxin-responsive gene expression. On the other hand, the role of CK2 in SA homeostasis and, indirectly, in SA-driven PID transcription, was confirmed by using Arabidopsis NahG transgenic plants, which cannot accumulate SA. In conclusion, our results evidence a role for CK2 as a functional link in the negative cross-talk between auxin- and SA-signaling.
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Affiliation(s)
- Laia Armengot
- Departament de Bioquímica i Biologia Molecular, Universitat Autònoma de Barcelona, Bellaterra (Barcelona), Spain
| | - Eleonora Caldarella
- Departament de Bioquímica i Biologia Molecular, Universitat Autònoma de Barcelona, Bellaterra (Barcelona), Spain
| | - Maria Mar Marquès-Bueno
- Departament de Bioquímica i Biologia Molecular, Universitat Autònoma de Barcelona, Bellaterra (Barcelona), Spain
| | - M. Carmen Martínez
- Departament de Bioquímica i Biologia Molecular, Universitat Autònoma de Barcelona, Bellaterra (Barcelona), Spain
- * E-mail:
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18
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Sah SK, Reddy KR, Li J. Abscisic Acid and Abiotic Stress Tolerance in Crop Plants. FRONTIERS IN PLANT SCIENCE 2016; 7:571. [PMID: 27200044 DOI: 10.3389/fpls.2016.00571/bibtex] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 02/06/2016] [Accepted: 04/13/2016] [Indexed: 05/27/2023]
Abstract
Abiotic stress is a primary threat to fulfill the demand of agricultural production to feed the world in coming decades. Plants reduce growth and development process during stress conditions, which ultimately affect the yield. In stress conditions, plants develop various stress mechanism to face the magnitude of stress challenges, although that is not enough to protect them. Therefore, many strategies have been used to produce abiotic stress tolerance crop plants, among them, abscisic acid (ABA) phytohormone engineering could be one of the methods of choice. ABA is an isoprenoid phytohormone, which regulates various physiological processes ranging from stomatal opening to protein storage and provides adaptation to many stresses like drought, salt, and cold stresses. ABA is also called an important messenger that acts as the signaling mediator for regulating the adaptive response of plants to different environmental stress conditions. In this review, we will discuss the role of ABA in response to abiotic stress at the molecular level and ABA signaling. The review also deals with the effect of ABA in respect to gene expression.
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Affiliation(s)
- Saroj K Sah
- Department of Biochemistry, Molecular Biology, Entomology and Plant Pathology, Mississippi State University Mississippi State, Mississippi, MS, USA
| | - Kambham R Reddy
- Department of Plant and Soil Sciences, Mississippi State University Mississippi State, Mississippi, MS, USA
| | - Jiaxu Li
- Department of Biochemistry, Molecular Biology, Entomology and Plant Pathology, Mississippi State University Mississippi State, Mississippi, MS, USA
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19
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Sah SK, Reddy KR, Li J. Abscisic Acid and Abiotic Stress Tolerance in Crop Plants. FRONTIERS IN PLANT SCIENCE 2016; 7:571. [PMID: 27200044 PMCID: PMC4855980 DOI: 10.3389/fpls.2016.00571] [Citation(s) in RCA: 546] [Impact Index Per Article: 68.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/06/2016] [Accepted: 04/13/2016] [Indexed: 05/17/2023]
Abstract
Abiotic stress is a primary threat to fulfill the demand of agricultural production to feed the world in coming decades. Plants reduce growth and development process during stress conditions, which ultimately affect the yield. In stress conditions, plants develop various stress mechanism to face the magnitude of stress challenges, although that is not enough to protect them. Therefore, many strategies have been used to produce abiotic stress tolerance crop plants, among them, abscisic acid (ABA) phytohormone engineering could be one of the methods of choice. ABA is an isoprenoid phytohormone, which regulates various physiological processes ranging from stomatal opening to protein storage and provides adaptation to many stresses like drought, salt, and cold stresses. ABA is also called an important messenger that acts as the signaling mediator for regulating the adaptive response of plants to different environmental stress conditions. In this review, we will discuss the role of ABA in response to abiotic stress at the molecular level and ABA signaling. The review also deals with the effect of ABA in respect to gene expression.
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Affiliation(s)
- Saroj K. Sah
- Department of Biochemistry, Molecular Biology, Entomology and Plant Pathology, Mississippi State UniversityMississippi State, Mississippi, MS, USA
| | - Kambham R. Reddy
- Department of Plant and Soil Sciences, Mississippi State UniversityMississippi State, Mississippi, MS, USA
| | - Jiaxu Li
- Department of Biochemistry, Molecular Biology, Entomology and Plant Pathology, Mississippi State UniversityMississippi State, Mississippi, MS, USA
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20
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Wang WS, Zhu J, Zhang KX, Lü YT, Xu HH. A mutation of casein kinase 2 α4 subunit affects multiple developmental processes in Arabidopsis. PLANT CELL REPORTS 2016; 35:1071-1080. [PMID: 26883224 DOI: 10.1007/s00299-016-1939-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/26/2015] [Accepted: 01/20/2016] [Indexed: 06/05/2023]
Abstract
Arabidopsis CK2 α4 subunit regulates the primary root and hypocotyl elongation, lateral root formation, cotyledon expansion, rosette leaf initiation and growth, flowering, and anthocyanin biosynthesis. Casein kinase 2 (CK2) is a conserved tetrameric kinase composed of two α and two β subunits. The inhibition of CK2 activity usually results in severe developmental deficiency. Four genes (CKA1-CKA4) encode CK2 α subunit in Arabidopsis. Single mutations of CKA1, CKA2, and CKA3 do not affect the normal growth of Arabidopsis, while the cka1 cka2 cka3 triple mutants are defective in cotyledon and hypocotyl growth, lateral root development, and flowering. The inhibition of CKA4 expression in cka1 cka2 cka3 background further reduces the number of lateral roots and delays the flowering time. Here, we report the characterization of a novel knockout mutant of CKA4, which exhibits various developmental defects including reduced primary root and hypocotyl elongation, increased lateral root density, delayed cotyledon expansion, retarded rosette leaf initiation and growth, and late flowering. The examination of the cellular basis for abnormal root development of this mutant revealed reduced root meristem cells with enhanced RETINOBLASTOMA-RELATED (RBR) expression that promotes cell differentiation in root meristem. Moreover, this cka4-2 mutant accumulates higher anthocyanin in the aerial part and shows an increased expression of anthocyanin biosynthetic genes, suggesting a novel role of CK2 in modulating anthocyanin biosynthesis. In addition, the complementation test using primary root elongation assay as a sample confirms that the changed phenotypes of this cka4-2 mutant are due to the lack of CKA4. Taken together, this study reveals an essential role of CK2 α4 subunit in multiple developmental processes in Arabidopsis.
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Affiliation(s)
- Wen-Shu Wang
- Jiangsu Key Laboratory of Marine Pharmaceutical Compound Screening, Huaihai Institute of Technology, Lianyungang, 222005, China
| | - Jiang Zhu
- Jiangsu Key Laboratory of Marine Pharmaceutical Compound Screening, Huaihai Institute of Technology, Lianyungang, 222005, China
| | - Kun-Xiao Zhang
- Jiangsu Key Laboratory of Marine Pharmaceutical Compound Screening, Huaihai Institute of Technology, Lianyungang, 222005, China
| | - Ying-Tang Lü
- Jiangsu Key Laboratory of Marine Pharmaceutical Compound Screening, Huaihai Institute of Technology, Lianyungang, 222005, China
| | - Heng-Hao Xu
- Jiangsu Key Laboratory of Marine Pharmaceutical Compound Screening, Huaihai Institute of Technology, Lianyungang, 222005, China.
- Co-Innovation Center of Jiangsu Marine Bio-industry Technology, Lianyungang, 222005, China.
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21
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Zhang L, Qi W, Xu H, Wang L, Jiao Z. Effects of low-energy N(+)-beam implantation on root growth in Arabidopsis seedlings. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2016; 124:111-119. [PMID: 26479682 DOI: 10.1016/j.ecoenv.2015.10.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2015] [Revised: 09/16/2015] [Accepted: 10/05/2015] [Indexed: 05/24/2023]
Abstract
The effects of ion implantation on the morphology changes and biological responses of plants are dependent on implantation doses. Previous studies mainly focus on the application of ion-beam technology in genetic mutation. Our knowledge regarding the mechanism underlying the plant growth inhibition induced by ion implantation remains limited. In this study, we explore the responses of root growth to low-energy N(+)-beam implantation using implanted Arabidopsis seeds. Our results showed that the root and root tip length were obviously reduced by implantation with large doses of low-energy N(+) beam. The analysis of confocal images showed that ion implantation reduced the cell viability and cell division activity in root meristem. The production rate of superoxide radical (O2(•-)) and contents of hydrogen peroxide (H2O2) in roots under ion implantation were markedly higher than those of controls. Transcriptional expression analysis of selected genes revealed that Arabidopsis RBOH genes associated with reactive oxygen species (ROS) production were significantly up-regulated in roots in response to ion implantation. The activities of antioxidant enzymes were also induced by ion implantation. Moreover, ROS scavenging obviously enhanced cell viability and cell division in response to ion implantation and alleviated the root growth inhibition of the implanted seedlings. Our results suggest that the overproduction of ROS induced by ion implantation is involved in the inhibitory effect of low-energy ion beam on root growth by affecting the cell viability and cell division of root meristem in Arabidopsis seedlings.
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Affiliation(s)
- Liang Zhang
- College of Life Science, Henan Normal University, Xinxiang 453007, China
| | - Wencai Qi
- College of Life Science, Henan Normal University, Xinxiang 453007, China
| | - Hangbo Xu
- Henan Provincial Key Laboratory of Ion Beam Bio-engineering, Zhengzhou University, Zhengzhou 450052, China
| | - Lin Wang
- Henan Provincial Key Laboratory of Ion Beam Bio-engineering, Zhengzhou University, Zhengzhou 450052, China
| | - Zhen Jiao
- Henan Provincial Key Laboratory of Ion Beam Bio-engineering, Zhengzhou University, Zhengzhou 450052, China.
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Phosphorylation Affects DNA-Binding of the Senescence-Regulating bZIP Transcription Factor GBF1. PLANTS 2015; 4:691-709. [PMID: 27135347 PMCID: PMC4844403 DOI: 10.3390/plants4030691] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/08/2015] [Revised: 08/12/2015] [Accepted: 09/08/2015] [Indexed: 11/28/2022]
Abstract
Massive changes in the transcriptome of Arabidopsis thaliana during onset and progression of leaf senescence imply a central role for transcription factors. While many transcription factors are themselves up- or down-regulated during senescence, the bZIP transcription factor G-box-binding factor 1 (GBF1/bZIP41) is constitutively expressed in Arabidopsis leaf tissue but at the same time triggers the onset of leaf senescence, suggesting posttranscriptional mechanisms for senescence-specific GBF1 activation. Here we show that GBF1 is phosphorylated by the threonine/serine CASEIN KINASE II (CKII) in vitro and that CKII phosphorylation had a negative effect on GBF1 DNA-binding to G-boxes of two direct target genes, CATALASE2 and RBSCS1a. Phosphorylation mimicry at three serine positions in the basic region of GBF1 also had a negative effect on DNA-binding. Kinase assays revealed that CKII phosphorylates at least one serine in the basic domain but has additional phosphorylation sites outside this domain. Two different ckII α subunit1 and one α subunit2 T-DNA insertion lines showed no visible senescence phenotype, but in all lines the expression of the senescence marker gene SAG12 was remarkably diminished. A model is presented suggesting that senescence-specific GBF1 activation might be achieved by lowering the phosphorylation of GBF1 by CKII.
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Mulekar JJ, Huq E. Arabidopsis casein kinase 2 α4 subunit regulates various developmental pathways in a functionally overlapping manner. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2015; 236:295-303. [PMID: 26025542 DOI: 10.1016/j.plantsci.2015.04.013] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2015] [Revised: 04/11/2015] [Accepted: 04/19/2015] [Indexed: 05/08/2023]
Abstract
Casein kinase 2 (CK2) is an essential and well-conserved Ser/Thr kinase that regulates proteins in a posttranslational manner. CK2 has been shown to affect a large number of developmental processes across eukaryotes. It is a tetrameric protein composed of a dimer of alpha (catalytic) and beta (regulatory) subunit each. In our previous study we showed that three of the four CK2 α subunits in Arabidopsis act in a functionally redundant manner to regulate various developmental pathways. In this study we constructed two independent CK2 α4 RNAi lines in the CK2 alpha triple mutant background. Through functional characterization of these RNAi lines we show that the fourth α subunit in Arabidopsis also functions redundantly in regulating ABA response, lateral root formation and flowering time. CK2 α4-GFP localizes to the chloroplast in transgenic Arabidopsis seedlings, consistent with the presence of a chloroplast localization signal at the amino-terminus of CK2 α4 subunit. Taken together, our results suggest a functionally overlapping role for the CK2 α4 subunit in regulating various developmental processes in plants.
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Affiliation(s)
- Jidnyasa Jayant Mulekar
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX 78712, USA; The Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin, TX 78712, USA
| | - Enamul Huq
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX 78712, USA; The Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin, TX 78712, USA.
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Vélez-Bermúdez IC, Carretero-Paulet L, Legnaioli T, Ludevid D, Pagès M, Riera M. Novel CK2α and CK2β subunits in maize reveal functional diversification in subcellular localization and interaction capacity. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2015; 235:58-69. [PMID: 25900566 DOI: 10.1016/j.plantsci.2015.03.005] [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: 12/30/2014] [Revised: 03/06/2015] [Accepted: 03/07/2015] [Indexed: 05/17/2023]
Abstract
In plants, CK2α/β subunits are encoded by multigenic families. They assemble as heterotetrameric holoenzymes or remain as individual subunits and are usually located in distinct cell compartments. Here we revise the number of maize CK2α/β genes, bringing them up to a total of eight (four CK2α catalytic and four CK2β regulatory subunits). We characterize CK2β4, which presents nuclear localization and interacts with CK2α1, CK2α3, CK2β1, and CK2β3. We also describe two CK2α isoforms (CK2α2 and CK2α4) containing N-terminal extensions that correspond to putative cTPs (chloroplast transit peptides). These cTPs are functional and responsible for the subcellular localization of CK2α2 and CK2α4 in chloroplasts. Phylogenetic analysis of the CK2α gene family, further supported by the gene structure and architecture of conserved protein domains, reveals the evolutionary expansion and diversification of this family. The subcellular localization of all four CK2α isoforms was found to be altered when were co-expressed with CK2β, thereby pointing to the latter as regulators of CK2α localization.
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Affiliation(s)
- I C Vélez-Bermúdez
- Center for Research in Agricultural Genomics (CRAG), CSIC-IRTA-UAB-UB Consortium, Campus UAB - Edifici CRAG, Bellaterra (Cerdanyola del Vallès), 08193 Barcelona, Spain
| | - L Carretero-Paulet
- Center for Research in Agricultural Genomics (CRAG), CSIC-IRTA-UAB-UB Consortium, Campus UAB - Edifici CRAG, Bellaterra (Cerdanyola del Vallès), 08193 Barcelona, Spain
| | - T Legnaioli
- Center for Research in Agricultural Genomics (CRAG), CSIC-IRTA-UAB-UB Consortium, Campus UAB - Edifici CRAG, Bellaterra (Cerdanyola del Vallès), 08193 Barcelona, Spain
| | - D Ludevid
- Center for Research in Agricultural Genomics (CRAG), CSIC-IRTA-UAB-UB Consortium, Campus UAB - Edifici CRAG, Bellaterra (Cerdanyola del Vallès), 08193 Barcelona, Spain
| | - M Pagès
- Center for Research in Agricultural Genomics (CRAG), CSIC-IRTA-UAB-UB Consortium, Campus UAB - Edifici CRAG, Bellaterra (Cerdanyola del Vallès), 08193 Barcelona, Spain
| | - M Riera
- Center for Research in Agricultural Genomics (CRAG), CSIC-IRTA-UAB-UB Consortium, Campus UAB - Edifici CRAG, Bellaterra (Cerdanyola del Vallès), 08193 Barcelona, Spain.
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Vilela B, Nájar E, Lumbreras V, Leung J, Pagès M. Casein Kinase 2 Negatively Regulates Abscisic Acid-Activated SnRK2s in the Core Abscisic Acid-Signaling Module. MOLECULAR PLANT 2015; 8:709-21. [PMID: 25744360 DOI: 10.1016/j.molp.2014.12.012] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/07/2014] [Revised: 12/06/2014] [Accepted: 12/07/2014] [Indexed: 05/17/2023]
Abstract
SnRK2 kinases, PP2C phosphatases and the PYR/PYL/RCAR receptors constitute the core abscisic acid (ABA) signaling module that is thought to contain all of the intrinsic properties to self-regulate the hormone signal output. Here we identify Casein Kinase (CK)2 as a novel negative regulator of SnRK2. CK2 phosphorylates a cluster of conserved serines at the ABA box of SnRK2, increasing its binding to PP2C and triggering protein degradation. Consequently, CK2 action has implications on SnRK2 protein levels, as well as kinase activity and its response to abiotic stimuli.
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Affiliation(s)
- Belmiro Vilela
- Centre for Research in Agricultural Genomics, Parc de Recerca UAB, Edifici CRAG, Campus UAB, Bellaterra (Cerdanyola del Vallès), 08193 Barcelona, Spain.
| | - Elena Nájar
- Centre for Research in Agricultural Genomics, Parc de Recerca UAB, Edifici CRAG, Campus UAB, Bellaterra (Cerdanyola del Vallès), 08193 Barcelona, Spain
| | - Victoria Lumbreras
- Centre for Research in Agricultural Genomics, Parc de Recerca UAB, Edifici CRAG, Campus UAB, Bellaterra (Cerdanyola del Vallès), 08193 Barcelona, Spain
| | - Jeffrey Leung
- ISV - Institut de Sciences du Végétal, CNRS, bat 23, avenue de la Terrasse, 91198 Gif-sur-Yvette Cedex, France
| | - Montserrat Pagès
- Centre for Research in Agricultural Genomics, Parc de Recerca UAB, Edifici CRAG, Campus UAB, Bellaterra (Cerdanyola del Vallès), 08193 Barcelona, Spain
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Vilela B, Pagès M, Riera M. Emerging roles of protein kinase CK2 in abscisic acid signaling. FRONTIERS IN PLANT SCIENCE 2015; 6:966. [PMID: 26579189 PMCID: PMC4630567 DOI: 10.3389/fpls.2015.00966] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2015] [Accepted: 10/22/2015] [Indexed: 05/02/2023]
Abstract
The phytohormone abscisic acid (ABA) regulates many aspects of plant growth and development as well as responses to multiple stresses. Post-translational modifications such as phosphorylation or ubiquitination have pivotal roles in the regulation of ABA signaling. In addition to the positive regulator sucrose non-fermenting-1 related protein kinase 2 (SnRK2), the relevance of the role of other protein kinases, such as CK2, has been recently highlighted. We have recently established that CK2 phosphorylates the maize ortholog of open stomata 1 OST1, ZmOST1, suggesting a role of CK2 phosphorylation in the control of ZmOST1 protein degradation (Vilela et al., 2015). CK2 is a pleiotropic enzyme involved in multiple developmental and stress-responsive pathways. This review summarizes recent advances that taken together suggest a prominent role of protein kinase CK2 in ABA signaling and related processes.
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Li Z, He C. Physalis floridana Cell Number Regulator1 encodes a cell membrane-anchored modulator of cell cycle and negatively controls fruit size. JOURNAL OF EXPERIMENTAL BOTANY 2015; 66:257-70. [PMID: 25305759 PMCID: PMC4265161 DOI: 10.1093/jxb/eru415] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Physalis species show a significant variation in berry size; however, the underlying molecular basis is unknown. In this work, we showed that cell division difference in the ovaries might contribute to the ultimate berry size variation within Physalis species, and that mRNA abundance of Physalis floridana Cell Number Regulator1 (PfCNR1), the putative orthologue of the tomato fruit weight 2.2 (FW2.2), was negatively correlated with cell division in the ovaries. Moreover, heterochronic expression variation of the PfCNR1 genes in the ovaries concomitantly correlated with berry weight variation within Physalis species. In transgenic Physalis, multiple organ sizes could be negatively controlled by altering PfCNR1 levels, and cell division instead of cell expansion was primarily affected. PfCNR1 was shown to be anchored in the plasma membrane and to interact with PfAG2 (an AGAMOUS-like protein determining ovary identity). The expression of PfCYCD2;1, a putative orthologue of the mitosis-specific gene CyclinD2;1 in the cell cycle was negatively correlated with the PfCNR1 mRNA levels. PfAG2 was found to selectively bind to the CArG-box in the PfCYCD2;1 promoter and to repress PfCYCD2;1 expression, thus suggesting a PfAG2-mediated pathway for PfCNR1 to regulate cell division. The interaction of PfCNR1 with PfAG2 enhanced the repression of PfCYCD2;1 expression. The nuclear import of PfAG2 was essential in the proposed pathway. Our data provide new insights into the developmental pathways of a cell membrane-anchored protein that modulates cell division and governs organ size determination. This study also sheds light on the link between organ identity and organ growth in plants.
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Affiliation(s)
- Zhichao Li
- State Key Laboratory of Systematic and Evolutionary Botany, Institute of Botany, Chinese Academy of Sciences, Nanxincun 20, Xiangshan, Haidian, 100093 Beijing, PR China University of Chinese Academy of Sciences, Yuquan Road 19, 100049 Beijing, PR China
| | - Chaoying He
- State Key Laboratory of Systematic and Evolutionary Botany, Institute of Botany, Chinese Academy of Sciences, Nanxincun 20, Xiangshan, Haidian, 100093 Beijing, PR China
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Wang Y, Chang H, Hu S, Lu X, Yuan C, Zhang C, Wang P, Xiao W, Xiao L, Xue GP, Guo X. Plastid casein kinase 2 knockout reduces abscisic acid (ABA) sensitivity, thermotolerance, and expression of ABA- and heat-stress-responsive nuclear genes. JOURNAL OF EXPERIMENTAL BOTANY 2014; 65:4159-75. [PMID: 24803505 PMCID: PMC4112627 DOI: 10.1093/jxb/eru190] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
Plastid casein kinase 2 (CK2) is a major Ser/Thr-specific enzyme for protein phosphorylation in the chloroplast stroma and its kinase activity is regulated by redox signals. To understand the role of CK2 phosphorylation of chloroplast proteins in abiotic stress signalling, an Arabidopsis plastid CK2 (CKA4) knockout mutant was investigated in terms of the plant response to abscisic acid (ABA) and heat stress. CKA4 expression was upregulated by ABA and heat treatment. The cka4 mutant showed reduced sensitivity to ABA during seed germination and seedling growth, and increased stomatal aperture and leaf water loss with a slightly reduced leaf ABA level. The cka4 mutant was more sensitive to heat stress than the wild-type Columbia-0. The expression levels of a number of genes in the ABA regulatory network were reduced in the cka4 mutant. Many heat-upregulated genes (heat-shock factors and heat-shock proteins) were also reduced in the cka4 mutant. The cka4 mutant showed reduced expression levels of plastid-encoded RNA polymerase target genes (atpB and psbA). CKA4 knockout mutation also resulted in a reduction in expression of some critical genes (PTM, ABI4, and PRS1) involved in retrograde signalling from the chloroplast to the nucleus. Similar results were observed in mutant plants with the knockout mutation in both CKA4 and CKA3, which encodes a nuclear CK2 α3 subunit. CKA3 expression was not responsive to ABA and heat stress. These results suggest that CKA4 is an enhancing factor in abiotic stress signalling through modulating the expression of some molecular players in retrograde signalling.
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Affiliation(s)
- Yu Wang
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Biology, Hunan University, Changsha 410082, PR China
| | - Hongping Chang
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Biology, Hunan University, Changsha 410082, PR China
| | - Shuai Hu
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Biology, Hunan University, Changsha 410082, PR China
| | - Xiutao Lu
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Biology, Hunan University, Changsha 410082, PR China
| | - Congying Yuan
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Biology, Hunan University, Changsha 410082, PR China
| | - Chen Zhang
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Biology, Hunan University, Changsha 410082, PR China
| | - Ping Wang
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Biology, Hunan University, Changsha 410082, PR China
| | - Wenjun Xiao
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Biology, Hunan University, Changsha 410082, PR China
| | - Langtao Xiao
- Hunan Provincial Key Laboratory of Phytohormones and Growth Development, Hunan Agricultural University, Changsha, 410128, PR China
| | - Gang-Ping Xue
- CSIRO Plant Industry, 306 Carmody Road, St Lucia, QLD 4067, Australia
| | - Xinhong Guo
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Biology, Hunan University, Changsha 410082, PR China
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Mulekar JJ, Huq E. Expanding roles of protein kinase CK2 in regulating plant growth and development. JOURNAL OF EXPERIMENTAL BOTANY 2014; 65:2883-93. [PMID: 24307718 DOI: 10.1093/jxb/ert401] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
Protein kinase CK2 (formerly known as casein kinase II) is a ubiquitious Ser/Thr kinase present in all eukaryotes. The α (catalytic) and β (regulatory) subunits of CK2 exist both as a tetrameric holoenzyme and as monomers in eukaryotic cells. CK2 has been implicated in multiple developmental and stress-responsive pathways including light signalling and circadian clock in plants. Recent studies using CK2 knockout and dominant negative mutants in Arabidopsis have uncovered new roles for this enzyme. CK2 substrates that have been identified so far are primarily transcription factors or regulatory proteins. CK2-mediated phosphorylation of these factors often results in alteration of the protein function including changes in the DNA-binding affinity, dimerization, stability, protein-protein interactions, and subcellular localization. CK2 has evolved as an essential housekeeping kinase in plants that modifies protein function in a dynamic way. This review summarizes the current knowledge of the role of CK2 in plant development.
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Affiliation(s)
- Jidnyasa Jayant Mulekar
- Department of Molecular Biosciences and Institute for Cellular and Molecular Biology, University of Texas at Austin, Austin, TX 78712, USA
| | - Enamul Huq
- Department of Molecular Biosciences and Institute for Cellular and Molecular Biology, University of Texas at Austin, Austin, TX 78712, USA
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30
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Armengot L, Marquès-Bueno MM, Soria-Garcia A, Müller M, Munné-Bosch S, Martínez MC. Functional interplay between protein kinase CK2 and salicylic acid sustains PIN transcriptional expression and root development. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2014; 78:411-23. [PMID: 24547808 DOI: 10.1111/tpj.12481] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/04/2013] [Revised: 01/27/2014] [Accepted: 02/10/2014] [Indexed: 05/12/2023]
Abstract
We have previously reported that CK2-defective Arabidopsis thaliana plants (CK2mut plants) were impaired severely in root development and auxin polar transport, and exhibited transcriptional misregulation of auxin-efflux transporters (Plant J., 67, 2011a, 169). In this work we show that CK2mut roots accumulate high levels of salicylic acid (SA) and that the gene that encodes isochorismate synthase (SID2) is overexpressed, strongly suggesting that CK2 activity is required for SA biosynthesis via the shikimate pathway. Moreover, SA activates transcription of CK2-encoding genes and, thus, SA and CK2 appear to be part of an autoregulatory feed-back loop to fine-tune each other's activities. We also show that exogenous SA and constitutive high SA levels in cpr mutants reproduce the CK2mut root phenotypes (decrease of root length and of number of lateral roots), whereas inhibition of CK2 activity in SA-defective and SA-signalling mutants lead to less severe phenotypes, suggesting that the CK2mut root phenotypes are SA-mediated effects. Moreover, exogenous SA mediates transcriptional repression of most of PIN-FORMED (PIN) genes, which is the opposite effect observed in CK2mut roots. These results prompted us to propose a model in which CK2 acts as a link between SA homeostasis and transcriptional regulation of auxin-efflux transporters. We also show that CK2 overexpression in Arabidopsis has neither impact on SA biosynthesis nor on auxin transport, but it improves the Arabidopsis root system. Thus, unlike the outcome in mammals, an excess of CK2 in plant cells does not produce neoplasia, but it might be advantageous for plant fitness.
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Affiliation(s)
- Laia Armengot
- Departament de Bioquímica i Biologia Molecular, Universitat Autònoma de Barcelona, 08193, Bellaterra (Barcelona), Spain
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Belda-Palazón B, Nohales MA, Rambla JL, Aceña JL, Delgado O, Fustero S, Martínez MC, Granell A, Carbonell J, Ferrando A. Biochemical quantitation of the eIF5A hypusination in Arabidopsis thaliana uncovers ABA-dependent regulation. FRONTIERS IN PLANT SCIENCE 2014; 5:202. [PMID: 24904603 PMCID: PMC4032925 DOI: 10.3389/fpls.2014.00202] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2014] [Accepted: 04/24/2014] [Indexed: 05/08/2023]
Abstract
The eukaryotic translation elongation factor eIF5A is the only protein known to contain the unusual amino acid hypusine which is essential for its biological activity. This post-translational modification is achieved by the sequential action of the enzymes deoxyhypusine synthase (DHS) and deoxyhypusine hydroxylase (DOHH). The crucial molecular function of eIF5A during translation has been recently elucidated in yeast and it is expected to be fully conserved in every eukaryotic cell, however the functional description of this pathway in plants is still sparse. The genetic approaches with transgenic plants for either eIF5A overexpression or antisense have revealed some activities related to the control of cell death processes but the molecular details remain to be characterized. One important aspect of fully understanding this pathway is the biochemical description of the hypusine modification system. Here we have used recombinant eIF5A proteins either modified by hypusination or non-modified to establish a bi-dimensional electrophoresis (2D-E) profile for the three eIF5A protein isoforms and their hypusinated or unmodified proteoforms present in Arabidopsis thaliana. The combined use of the recombinant 2D-E profile together with 2D-E/western blot analysis from whole plant extracts has provided a quantitative approach to measure the hypusination status of eIF5A. We have used this information to demonstrate that treatment with the hormone abscisic acid produces an alteration of the hypusine modification system in Arabidopsis thaliana. Overall this study presents the first biochemical description of the post-translational modification of eIF5A by hypusination which will be functionally relevant for future studies related to the characterization of this pathway in Arabidopsis thaliana.
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Affiliation(s)
- Borja Belda-Palazón
- Instituto de Biología Molecular y Celular de Plantas, CSIC-Universidad Politécnica de ValenciaValencia, Spain
| | - María A. Nohales
- Instituto de Biología Molecular y Celular de Plantas, CSIC-Universidad Politécnica de ValenciaValencia, Spain
| | - José L. Rambla
- Instituto de Biología Molecular y Celular de Plantas, CSIC-Universidad Politécnica de ValenciaValencia, Spain
| | - José L. Aceña
- Centro de Investigación Príncipe FelipeValencia, Spain
| | - Oscar Delgado
- Centro de Investigación Príncipe FelipeValencia, Spain
| | - Santos Fustero
- Centro de Investigación Príncipe FelipeValencia, Spain
- Departamento de Química Orgánica, Universidad de ValenciaValencia, Spain
| | - M. Carmen Martínez
- Departament de Bioquímica i Biologia Molecular, Universitat Autònoma de BarcelonaBarcelona, Spain
| | - Antonio Granell
- Instituto de Biología Molecular y Celular de Plantas, CSIC-Universidad Politécnica de ValenciaValencia, Spain
| | - Juan Carbonell
- Instituto de Biología Molecular y Celular de Plantas, CSIC-Universidad Politécnica de ValenciaValencia, Spain
| | - Alejandro Ferrando
- Instituto de Biología Molecular y Celular de Plantas, CSIC-Universidad Politécnica de ValenciaValencia, Spain
- *Correspondence: Alejandro Ferrando, Instituto de Biología Molecular y Celular de Plantas, CSIC-Universidad Politécnica de Valencia, C/Ingeniero Fausto Elio, s/n, 46022 Valencia, Spain e-mail:
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Xu J, Xiong W, Cao B, Yan T, Luo T, Fan T, Luo M. Molecular characterization and functional analysis of "fruit-weight 2.2-like" gene family in rice. PLANTA 2013; 238:643-655. [PMID: 23793979 DOI: 10.1007/s00425-013-1916-y] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/06/2013] [Accepted: 06/06/2013] [Indexed: 06/02/2023]
Abstract
Tomato fruit-weight 2.2 (FW2.2) was reported to control up to 30 % fruit weight. Recent studies demonstrated that FW2.2-like (FWL) genes also play important roles in plant growth and development. For instance, a maize homolog of FW2.2, named cell number regulator 1 (CNR1), negatively regulates plant and organ size. However, FWL genes in rice have not been characterized yet. In this study, eight FWL genes were identified in rice genome and designated as OsFWL1-8. The chromosome location, gene structure, protein motif, and phylogenetic relationship of OsFWL genes were analyzed. RT-PCR result and microarray data revealed that OsFWL genes exhibited diverse expression patterns and the detailed expression patterns of OsFWL5, 6, and 7 negatively correlated with leaf growth activity. Rice protoplast transient transformation experiment showed that most OsFWL proteins locate at cell membrane but OsFWL8 is present in the nucleus. In addition, the functions of OsFWL genes were investigated by analyzing two T-DNA insertion lines for OsFWL3 and 5. Compared with wild type, the grain weight of osfwl3 mutant and the plant height of osfwl5 mutant were increased by 5.3 and 12.5 %, respectively. We also found that the increase in grain length of osfwl3 mutant was due chiefly to incremental cell number, not cell size and the expression of OsFWL3 negatively correlated with glume growth activity. These results provide a comprehensive foundation for further study of OsFWL functions in rice.
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Affiliation(s)
- Jun Xu
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, 430070, China
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Boex-Fontvieille E, Daventure M, Jossier M, Zivy M, Hodges M, Tcherkez G. Photosynthetic control of Arabidopsis leaf cytoplasmic translation initiation by protein phosphorylation. PLoS One 2013; 8:e70692. [PMID: 23894680 PMCID: PMC3722150 DOI: 10.1371/journal.pone.0070692] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2013] [Accepted: 06/20/2013] [Indexed: 01/26/2023] Open
Abstract
Photosynthetic CO2 assimilation is the carbon source for plant anabolism, including amino acid production and protein synthesis. The biosynthesis of leaf proteins is known for decades to correlate with photosynthetic activity but the mechanisms controlling this effect are not documented. The cornerstone of the regulation of protein synthesis is believed to be translation initiation, which involves multiple phosphorylation events in Eukaryotes. We took advantage of phosphoproteomic methods applied to Arabidopsis thaliana rosettes harvested under controlled photosynthetic gas-exchange conditions to characterize the phosphorylation pattern of ribosomal proteins (RPs) and eukaryotic initiation factors (eIFs). The analyses detected 14 and 11 new RP and eIF phosphorylation sites, respectively, revealed significant CO2-dependent and/or light/dark phosphorylation patterns and showed concerted changes in 13 eIF phosphorylation sites and 9 ribosomal phosphorylation sites. In addition to the well-recognized role of the ribosomal small subunit protein RPS6, our data indicate the involvement of eIF3, eIF4A, eIF4B, eIF4G and eIF5 phosphorylation in controlling translation initiation when photosynthesis varies. The response of protein biosynthesis to the photosynthetic input thus appears to be the result of a complex regulation network involving both stimulating (e.g. RPS6, eIF4B phosphorylation) and inhibiting (e.g. eIF4G phosphorylation) molecular events.
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Affiliation(s)
- Edouard Boex-Fontvieille
- Institut de Biologie des Plantes, CNRS UMR 8618, Saclay Plant Sciences, Université Paris-Sud, Orsay, France
| | - Marlène Daventure
- Plateforme PAPPSO, UMR de Génétique Végétale, Ferme du Moulon, Gif sur Yvette, France
| | - Mathieu Jossier
- Institut de Biologie des Plantes, CNRS UMR 8618, Saclay Plant Sciences, Université Paris-Sud, Orsay, France
| | - Michel Zivy
- Plateforme PAPPSO, UMR de Génétique Végétale, Ferme du Moulon, Gif sur Yvette, France
| | - Michael Hodges
- Institut de Biologie des Plantes, CNRS UMR 8618, Saclay Plant Sciences, Université Paris-Sud, Orsay, France
| | - Guillaume Tcherkez
- Institut de Biologie des Plantes, CNRS UMR 8618, Saclay Plant Sciences, Université Paris-Sud, Orsay, France
- Institut Universitaire de France, Paris, France
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Moreno-Romero J, Armengot L, Mar Marquès-Bueno M, Britt A, Carmen Martínez M. CK2-defective Arabidopsis plants exhibit enhanced double-strand break repair rates and reduced survival after exposure to ionizing radiation. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2012; 71:627-638. [PMID: 22487192 DOI: 10.1111/j.1365-313x.2012.05019.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
The multifunctional protein kinase CK2 is involved in several aspects of the DNA damage response (DDR) in mammals. To gain insight into the role of CK2 in plant genome maintenance, we studied the response to genotoxic agents of an Arabidopsis CK2 dominant-negative mutant (CK2mut plants). CK2mut plants were hypersensitive to a wide range of genotoxins that produce a variety of DNA lesions. However, they were able to activate the DDR after exposure to γ irradiation, as shown by accumulation of phosphorylated histone H2AX and up-regulation of sets of radio-modulated genes. Moreover, functional assays showed that mutant plants quickly repair the DNA damage produced by genotoxins, and that they exhibit preferential use of non-conservative mechanisms, which may explain plant lethality. The chromatin of CK2mut plants was more sensitive to digestion with micrococcal nuclease, suggesting compaction changes that agreed with the transcriptional changes detected for a number of genes involved in chromatin structure. Furthermore, CK2mut plants were prone to transcriptional gene silencing release upon genotoxic stress. Our results suggest that CK2 is required in the maintenance and control of genomic stability and chromatin structure in plants, and that this process affects several functions, including the DNA damage response and DNA repair.
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Affiliation(s)
- Jordi Moreno-Romero
- Departament de Bioquímica i Biologia Molecular, Universitat Autònoma de Barcelona, 08193 Bellaterra, Barcelona, Spain
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35
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Mulekar JJ, Bu Q, Chen F, Huq E. Casein kinase II α subunits affect multiple developmental and stress-responsive pathways in Arabidopsis. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2012; 69:343-54. [PMID: 21950772 DOI: 10.1111/j.1365-313x.2011.04794.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Casein kinase II (formerly known as CK2), a ubiquitous Ser/Thr kinase, plays critical roles in all higher organisms including plants. The CK2 holoenzyme consists of two catalytic α subunits and two regulatory β subunits. The Arabidopsis genome has four α subunit and four β subunit genes, and members of both the α and β subunit families have been shown to be localized in the cytoplasm, nucleus and also in chloroplasts. However, the biological roles of CK2 subunits have not been fully characterized yet. Here we identified T-DNA insertion mutants in three α subunit genes (α1, α2 and α3) and made double and triple mutants. The CK2 α1α2α3 triple mutants displayed reduced CK2 activity compared with wild-type seedlings. Phenotypic characterization showed that CK2 α1α2α3 triple mutants are late flowering under both long- and short-day conditions. Genes encoding floral integrators are differentially regulated in the triple mutant compared with the wild-type plants. CK2 α1α2α3 triple mutants also displayed reduced hypocotyl growth, smaller cotyledon size and a reduced number of lateral roots compared with wild-type seedlings under light. Abscisic acid-induced blockage of seed germination and cotyledon greening is reduced in CK2 α subunit mutants in an additive manner. Moreover, CK2 α subunit mutants are also hyposensitive to a NaCl-induced blockage of seed germination. Taken together, these data suggest that CK2 α subunits affect diverse developmental and stress responsive pathways in Arabidopsis.
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Affiliation(s)
- Jidnyasa Jayant Mulekar
- Section of Molecular Cell and Developmental Biology and The Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin, TX 78712, USA
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Lu SX, Liu H, Knowles SM, Li J, Ma L, Tobin EM, Lin C. A role for protein kinase casein kinase2 α-subunits in the Arabidopsis circadian clock. PLANT PHYSIOLOGY 2011; 157:1537-45. [PMID: 21900482 PMCID: PMC3252133 DOI: 10.1104/pp.111.179846] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2011] [Accepted: 09/05/2011] [Indexed: 05/17/2023]
Abstract
Circadian rhythms are autoregulatory, endogenous rhythms with a period of approximately 24 h. A wide variety of physiological and molecular processes are regulated by the circadian clock in organisms ranging from bacteria to humans. Phosphorylation of clock proteins plays a critical role in generating proper circadian rhythms. Casein Kinase2 (CK2) is an evolutionarily conserved serine/threonine protein kinase composed of two catalytic α-subunits and two regulatory β-subunits. Although most of the molecular components responsible for circadian function are not conserved between kingdoms, CK2 is a well-conserved clock component modulating the stability and subcellular localization of essential clock proteins. Here, we examined the effects of a cka1a2a3 triple mutant on the Arabidopsis (Arabidopsis thaliana) circadian clock. Loss-of-function mutations in three nuclear-localized CK2α subunits result in period lengthening of various circadian output rhythms and central clock gene expression, demonstrating that the cka1a2a3 triple mutant affects the pace of the circadian clock. Additionally, the cka1a2a3 triple mutant has reduced levels of CK2 kinase activity and CIRCADIAN CLOCK ASSOCIATED1 phosphorylation in vitro. Finally, we found that the photoperiodic flowering response, which is regulated by circadian rhythms, was reduced in the cka1a2a3 triple mutant and that the plants flowered later under long-day conditions. These data demonstrate that CK2α subunits are important components of the Arabidopsis circadian system and their effects on rhythms are in part due to their phosphorylation of CIRCADIAN CLOCK ASSOCIATED1.
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Marquès-Bueno MM, Moreno-Romero J, Abas L, de Michele R, Martínez MC. Linking protein kinase CK2 and auxin transport. PLANT SIGNALING & BEHAVIOR 2011; 6:1603-5. [PMID: 21918377 PMCID: PMC3256396 DOI: 10.4161/psb.6.10.17136] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Studies performed in different organisms have highlighted the importance of protein kinase CK2 in cell growth and cell viability. However, the plant signaling pathways in which CK2 is involved are largely unknown. We have reported that a dominant-negative mutant of CK2 in Arabidopsis thaliana shows phenotypic traits that are typically linked to alterations in auxin-dependent processes. We demonstrated that auxin transport is, indeed, impaired in these mutant plants, and that this correlates with misexpression and mislocalization of PIN efflux transporters and of PINOID. Our data establishes a link between CK2 activity and the regulation of auxin homeostasis in plants, strongly suggesting that CK2 might be required at multiple points of the pathways regulating auxin fluxes.
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Affiliation(s)
- Maria Mar Marquès-Bueno
- Departament de Bioquímica i Biologia Molecular, Facultat de Biociències, Universitat Autònoma de Barcelona, Bellaterra, Spain
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Riera M, Irar S, Vélez-Bermúdez IC, Carretero-Paulet L, Lumbreras V, Pagès M. Role of plant-specific N-terminal domain of maize CK2β1 subunit in CK2β functions and holoenzyme regulation. PLoS One 2011; 6:e21909. [PMID: 21789193 PMCID: PMC3137599 DOI: 10.1371/journal.pone.0021909] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2010] [Accepted: 06/14/2011] [Indexed: 11/19/2022] Open
Abstract
Protein kinase CK2 is a highly pleiotropic Ser/Thr kinase ubiquituous in eukaryotic organisms. CK2 is organized as a heterotetrameric enzyme composed of two types of subunits: the catalytic (CK2α) and the regulatory (CK2β). The CK2β subunits enhance the stability, activity and specificity of the holoenzyme, but they can also perform functions independently of the CK2 tetramer. CK2β regulatory subunits in plants differ from their animal or yeast counterparts, since they present an additional specific N-terminal extension of about 90 aminoacids that shares no homology with any previously characterized functional domain. Sequence analysis of the N-terminal domain of land plant CK2β subunit sequences reveals its arrangement through short, conserved motifs, some of them including CK2 autophosphorylation sites. By using maize CK2β1 and a deleted version (ΔNCK2β1) lacking the N-terminal domain, we have demonstrated that CK2β1 is autophosphorylated within the N-terminal domain. Moreover, the holoenzyme composed with CK2α1/ΔNCK2β1 is able to phosphorylate different substrates more efficiently than CK2α1/CK2β1 or CK2α alone. Transient overexpression of CK2β1 and ΔNCK2β1 fused to GFP in different plant systems show that the presence of N-terminal domain enhances aggregation in nuclear speckles and stabilizes the protein against proteasome degradation. Finally, bimolecular fluorescence complementation (BiFC) assays show the nuclear and cytoplasmic location of the plant CK2 holoenzyme, in contrast to the individual CK2α/β subunits mainly observed in the nucleus. All together, our results support the hypothesis that the plant-specific N-terminal domain of CK2β subunits is involved in the down-regulation of the CK2 holoenzyme activity and in the stabilization of CK2β1 protein. In summary, the whole amount of data shown in this work suggests that this domain was acquired by plants for regulatory purposes.
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Affiliation(s)
- Marta Riera
- Department of Molecular Genetics, Centre for Research on Agricultural Genomics CRAG (CSIC-IRTA-UAB), Barcelona, Spain
| | - Sami Irar
- Department of Molecular Genetics, Centre for Research on Agricultural Genomics CRAG (CSIC-IRTA-UAB), Barcelona, Spain
| | - Isabel C. Vélez-Bermúdez
- Department of Molecular Genetics, Centre for Research on Agricultural Genomics CRAG (CSIC-IRTA-UAB), Barcelona, Spain
| | - Lorenzo Carretero-Paulet
- Department of Molecular Genetics, Centre for Research on Agricultural Genomics CRAG (CSIC-IRTA-UAB), Barcelona, Spain
- Department of Applied Biology (Area of Genetics). University of Almería, Spain
| | - Victoria Lumbreras
- Department of Molecular Genetics, Centre for Research on Agricultural Genomics CRAG (CSIC-IRTA-UAB), Barcelona, Spain
| | - Montserrat Pagès
- Department of Molecular Genetics, Centre for Research on Agricultural Genomics CRAG (CSIC-IRTA-UAB), Barcelona, Spain
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Dominguez I, Degano IR, Chea K, Cha J, Toselli P, Seldin DC. CK2α is essential for embryonic morphogenesis. Mol Cell Biochem 2011; 356:209-16. [PMID: 21761203 DOI: 10.1007/s11010-011-0961-8] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2011] [Accepted: 06/24/2011] [Indexed: 12/11/2022]
Abstract
CK2 is a highly conserved serine-threonine kinase involved in biological processes such as embryonic development, circadian rhythms, inflammation, and cancer. Biochemical experiments have implicated CK2 in the control of several cellular processes and in the regulation of signal transduction pathways. Our laboratory is interested in characterizing the cellular, signaling, and molecular mechanisms regulated by CK2 during early embryonic development. For this purpose, animal models, including mice deficient in CK2 genes, are indispensable tools. Using CK2α gene-deficient mice, we have recently shown that CK2α is a critical regulator of mid-gestational morphogenetic processes, as CK2α deficiency results in defects in heart, brain, pharyngeal arch, tail bud, limb bud, and somite formation. Morphogenetic processes depend upon the precise coordination of essential cellular processes in which CK2 has been implicated, such as proliferation and survival. Here, we summarize the overall phenotype found in CK2α (-/- ) mice and describe our initial analysis aimed to identify the cellular processes affected in CK2α mutants.
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Affiliation(s)
- Isabel Dominguez
- Department of Medicine, Boston University School of Medicine, Boston, MA 02118, USA.
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Velez-Bermudez IC, Irar S, Carretero-Paulet L, Pagès M, Riera M. Specific characteristics of CK2β regulatory subunits in plants. Mol Cell Biochem 2011; 356:255-60. [PMID: 21750977 DOI: 10.1007/s11010-011-0971-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2011] [Accepted: 06/24/2011] [Indexed: 01/20/2023]
Abstract
In all eukaryotes, the typical CK2 holoenzyme is an heterotetramer composed of two catalytic (CK2α and CK2α') and two regulatory (CK2β) subunits. One of the distinctive traits of plant CK2 is that they present a greater number of genes encoding for CK2α/β subunits than animals or yeasts, for instance, in Arabidopsis and maize both CK2α/β subunits belong to multigenic families composed by up to four genes. Here, we conducted a genome-wide survey examining 34 different plant genomes in order to investigate if the multigenic property of CK2β genes is a common feature through the entire plant kingdom. Also, at the level of structure, the plant CK2β regulatory subunits present distinctive features as (i) they lack about 20 aminoacids in the C-terminal domain, (ii) they present a specific N-terminal extension of about 90 aminoacids that shares no homology with any previously characterized functional domain, and (iii) the acidic loop region is poorly conserved at the aminoacid level. Since there is no data about CK2β or holoenzyme structure in plants, in this study, we use human CK2β as a template to predict a structure for Zea mays CK2β1 by homology modeling and we discuss about possible structural changes in the acidic loop region that could affect the enzyme regulation.
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Affiliation(s)
- Isabel Cristina Velez-Bermudez
- Molecular Genetics Department, Centre for Research on Agricultural Genomics CRAG, Campus UAB 08193 Bellaterra, Cerdanyola del Vallès, Barcelona, Spain
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41
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About the role of CK2 in plant signal transduction. Mol Cell Biochem 2011; 356:233-40. [DOI: 10.1007/s11010-011-0970-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2011] [Accepted: 06/24/2011] [Indexed: 12/24/2022]
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42
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The p23 co-chaperone protein is a novel substrate of CK2 in Arabidopsis. Mol Cell Biochem 2011; 356:245-54. [DOI: 10.1007/s11010-011-0969-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2011] [Accepted: 06/24/2011] [Indexed: 11/26/2022]
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Marquès-Bueno MM, Moreno-Romero J, Abas L, De Michele R, Martínez MC. A dominant negative mutant of protein kinase CK2 exhibits altered auxin responses in Arabidopsis. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2011; 67:169-80. [PMID: 21435053 DOI: 10.1111/j.1365-313x.2011.04585.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Protein kinase CK2 is a pleiotropic Ser/Thr kinase, evolutionary conserved in eukaryotes. Studies performed in different organisms, from yeast to humans, have highlighted the importance of CK2 in cell growth and cell-cycle control. However, the signalling pathways in which CK2 is involved have not been fully identified. In plants, the phytohormone auxin is a major regulator of cell growth. Recent discoveries have demonstrated that differential distribution of within auxin plant tissues is essential for developmental processes, and that this distribution is dependent on polar auxin transport. We report here that a dominant-negative mutant of CK2 (CK2mut) in Arabidopsis thaliana shows phenotypic traits that are typically linked to alterations in auxin-dependent processes. However, CK2mut plants exhibit normal responses to exogenous indole-3-acetic acid (IAA) indicating that they are not affected in the perception of the hormone but upstream in the pathway. We demonstrate that mutant plants are not deficient in IAA but are impaired in its transport. Using genetic and pharmacological tools we show that CK2 activity depletion hinders correct formation of auxin gradients and leads to widespread changes in the expression of auxin-related genes. In particular, members of the auxin efflux carrier family (PINs), and the protein kinase PINOID, both key regulators of auxin fluxes, were misexpressed. PIN4 and PIN7 were also found mislocalized, with accumulation in endosomal bodies. We propose that CK2 functions in the regulation of auxin-signalling pathways, particularly in auxin transport.
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Affiliation(s)
- Maria Mar Marquès-Bueno
- Departament de Bioquímica i Biologia Molecular, Facultat de Biociències, Universitat Autònoma de Barcelona, 08193 Bellaterra (Barcelona), Spain
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Bu Q, Zhu L, Dennis MD, Yu L, Lu SX, Person MD, Tobin EM, Browning KS, Huq E. Phosphorylation by CK2 enhances the rapid light-induced degradation of phytochrome interacting factor 1 in Arabidopsis. J Biol Chem 2011; 286:12066-74. [PMID: 21330376 DOI: 10.1074/jbc.m110.186882] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
The phytochrome family of sensory photoreceptors interacts with phytochrome interacting factors (PIFs), repressors of photomorphogenesis, in response to environmental light signals and induces rapid phosphorylation and degradation of PIFs to promote photomorphogenesis. However, the kinase that phosphorylates PIFs is still unknown. Here we show that CK2 directly phosphorylates PIF1 at multiple sites. α1 and α2 subunits individually phosphorylated PIF1 weakly in vitro. However, each of four β subunits strongly stimulated phosphorylation of PIF1 by α1 or α2. Mapping of the phosphorylation sites identified seven Ser/Thr residues scattered throughout PIF1. Ser/Thr to Ala scanning mutations at all seven sites eliminated CK2-mediated phosphorylation of PIF1 in vitro. Moreover, the rate of degradation of the Ser/Thr to Ala mutant PIF1 was significantly reduced compared with wild-type PIF1 in transgenic plants. In addition, hypocotyl lengths of the mutant PIF1 transgenic plants were much longer than the wild-type PIF1 transgenic plants under light, suggesting that the mutant PIF1 is suppressing photomorphogenesis. Taken together, these data suggest that CK2-mediated phosphorylation enhances the light-induced degradation of PIF1 to promote photomorphogenesis.
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Affiliation(s)
- Qingyun Bu
- Section of Molecular Cell and Developmental Biology, Department of Chemistry and Biochemistry, The Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin, TX 78712, USA
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45
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Portolés S, Más P. The functional interplay between protein kinase CK2 and CCA1 transcriptional activity is essential for clock temperature compensation in Arabidopsis. PLoS Genet 2010; 6:e1001201. [PMID: 21079791 PMCID: PMC2973838 DOI: 10.1371/journal.pgen.1001201] [Citation(s) in RCA: 86] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2010] [Accepted: 10/07/2010] [Indexed: 01/17/2023] Open
Abstract
Circadian rhythms are daily biological oscillations driven by an endogenous mechanism known as circadian clock. The protein kinase CK2 is one of the few clock components that is evolutionary conserved among different taxonomic groups. CK2 regulates the stability and nuclear localization of essential clock proteins in mammals, fungi, and insects. Two CK2 regulatory subunits, CKB3 and CKB4, have been also linked with the Arabidopsis thaliana circadian system. However, the biological relevance and the precise mechanisms of CK2 function within the plant clockwork are not known. By using ChIP and Double-ChIP experiments together with in vivo luminescence assays at different temperatures, we were able to identify a temperature-dependent function for CK2 modulating circadian period length. Our study uncovers a previously unpredicted mechanism for CK2 antagonizing the key clock regulator CIRCADIAN CLOCK-ASSOCIATED 1 (CCA1). CK2 activity does not alter protein accumulation or subcellular localization but interferes with CCA1 binding affinity to the promoters of the oscillator genes. High temperatures enhance the CCA1 binding activity, which is precisely counterbalanced by the CK2 opposing function. Altering this balance by over-expression, mutation, or pharmacological inhibition affects the temperature compensation profile, providing a mechanism by which plants regulate circadian period at changing temperatures. Therefore, our study establishes a new model demonstrating that two opposing and temperature-dependent activities (CCA1-CK2) are essential for clock temperature compensation in Arabidopsis.
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Affiliation(s)
- Sergi Portolés
- Consortium CSIC-IRTA-UAB, Centre for Research in Agricultural Genomics (CRAG), Department of Plant Molecular Genetics, Barcelona, Spain
| | - Paloma Más
- Consortium CSIC-IRTA-UAB, Centre for Research in Agricultural Genomics (CRAG), Department of Plant Molecular Genetics, Barcelona, Spain
- * E-mail:
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Libault M, Stacey G. Evolution of FW2.2-like (FWL) and PLAC8 genes in eukaryotes. PLANT SIGNALING & BEHAVIOR 2010; 5:1226-8. [PMID: 20855956 PMCID: PMC3115352 DOI: 10.4161/psb.5.10.12808] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
The tomato FW2.2 quantitative trait locus, which regulates tomato fruit size, was genetically and physically mapped around 15 years ago. Subsequently, the FW2.2 gene was cloned and shown to contain a PLAC8 domain, originally identified in mammalian placental proteins. Data suggest that FW2.2 likely controls tomato cell size, perhaps by direct interaction with casein kinase II. Several FW2.2-like (FWL) genes have now been identified from a variety of plant species, but until recently only the tomato FW2.2 gene had been the subject of detailed investigation. Recently, soybean and maize FWL genes were identified and shown to have a role in plant organogenesis. It is now apparent that the FWL genes in plants are a large gene family, which is even larger given inclusion of genes for the various eukaryotic PLAC8-domain proteins. Although overall the protein sequence identity/similarity among the family members is relatively low, there is strong conservation of key domains, suggesting a conservation of the core biochemical function of these proteins. In this Addendum Article, we highlight the similarities and differences exiting between plant FWL genes and enlarge this comparison to the mammalian PLAC8 genes. These comparisons suggest the possible conservation of biological function for FWL proteins.
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Affiliation(s)
- Marc Libault
- Division of Plant Sciences, National Center for Soybean Biotechnology, C.S. Bond Life Sciences Center, University of Missouri, Columbia, MO, USA.
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47
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Libault M, Zhang XC, Govindarajulu M, Qiu J, Ong YT, Brechenmacher L, Berg RH, Hurley-Sommer A, Taylor CG, Stacey G. A member of the highly conserved FWL (tomato FW2.2-like) gene family is essential for soybean nodule organogenesis. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2010; 62:852-64. [PMID: 20230508 DOI: 10.1111/j.1365-313x.2010.04201.x] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
A soybean homolog of the tomato FW2.2 gene, here named GmFWL1 (Glycine max FW2.2-like 1), was found to respond strongly to inoculation with the nitrogen-fixing symbiotic bacterium Bradyrhizobium japonicum. In tomato, the FW2.2 gene is hypothesized to control 30% of the variance in fruit weight by negatively regulating cell division. In the present study, the induction of GmFWL1 expression in root hair cells and nodules in response to B. japonicum inoculation was documented using quantitative RT-PCR and transcriptional fusions to both beta-glucuronidase (GUS) and green fluorescent protein (GFP). RNAi-mediated silencing of GmFWL1 expression resulted in a significant reduction in nodule number, with a concomitant reduction in nuclear size and changes in chromatin structure. The reduction in nuclear size is probably due to a change in DNA heterochromatinization, as the ploidy level of wild-type and RNAi-silenced nodule cells was similar. GmFWL1 was localized to the plasma membrane. The data suggest that GmFWL1 probably acts indirectly, perhaps through a cellular cascade, to affect chromatin structure/nuclei architecture. As previously proposed in tomato, this function may be a result of effects on plant cell division.
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Affiliation(s)
- Marc Libault
- Division of Plant Sciences, National Center for Soybean Biotechnology, Division of Biochemistry, C.S. Bond Life Sciences Center, University of Missouri, Columbia, MO 65211, USA
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Schweer J, Türkeri H, Link B, Link G. AtSIG6, a plastid sigma factor from Arabidopsis, reveals functional impact of cpCK2 phosphorylation. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2010; 62:192-202. [PMID: 20088902 PMCID: PMC2988416 DOI: 10.1111/j.1365-313x.2010.04138.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/24/2009] [Accepted: 12/23/2009] [Indexed: 05/17/2023]
Abstract
Plastids contain sigma factors, i.e. gene-regulatory proteins for promoter binding and transcription initiation. Despite the physical and functional similarity shared with their prokaryotic counterparts, the plant sigma factors have distinguishing features: most notably the existence of a variable extra sequence comprising their N-terminal portions. This distinct architecture is reflected by functional differences, including phosphorylation control by organellar protein kinase(s) closely related to nucleocytosolic, rather than bacterial-type, enzymes. In particular, cpCK2, a nuclear-coded plastid-targeted casein kinase 2, has been implicated as a key component in plant sigma factor phosphorylation and transcriptional regulation (Eur. J. Biochem. 269, 2002, 3329; Planta, 219, 2004, 298). Although this notion is based mainly on biochemical evidence and in vitro systems, the recent availability of Arabidopsis sigma knock-out lines for complementation by intact and mutant sigma cDNAs has opened up new strategies for the study of transcription regulatory mechanisms in vivo. Using Arabidopsis sigma factor 6 (AtSIG6) as a paradigm, we present data suggesting that: (i) this factor is a substrate for regulatory phosphorylation by cpCK2 both in vitro and in vivo; (ii) cpCK2 phosphorylation of SIG6 occurs at multiple sites, which can widely differ in their effect on the visual and/or molecular phenotype; (iii) in vivo usage of the perhaps most critical cpCK2 site defined by Ser174 requires (pre-)phosphorylation at the n + 3 serine residue Ser177, pointing to 'pathfinder' kinase activity capable of generating a functional cpCK2 substrate site.
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Affiliation(s)
| | | | | | - Gerhard Link
- *For correspondence (fax: +49 234 321 4188; e-mail )
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49
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Łebska M, Ciesielski A, Szymona L, Godecka L, Lewandowska-Gnatowska E, Szczegielniak J, Muszyńska G. Phosphorylation of maize eukaryotic translation initiation factor 5A (eIF5A) by casein kinase 2: identification of phosphorylated residue and influence on intracellular localization of eIF5A. J Biol Chem 2010; 285:6217-26. [PMID: 20018887 PMCID: PMC2825417 DOI: 10.1074/jbc.m109.018770] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2009] [Revised: 12/15/2009] [Indexed: 11/06/2022] Open
Abstract
Maize eukaryotic translation initiation factor 5A (ZmeIF5A) co-purifies with the catalytic alpha subunit of protein kinase CK2 and is phosphorylated by this enzyme. Phosphorylated ZmeIF5A was also identified after separation of maize leaf proteins by two-dimensional electrophoresis. Multiple sequence alignment of eIF5A proteins showed that in monocots, in contrast to other eukaryotes, there are two serine/threonine residues that could potentially be phosphorylated by CK2. To identify the phosphorylation site(s) of ZmeIF5A, the serine residues potentially phosphorylated by CK2 were mutated. ZmeIF5A and its mutated variants S2A and S4A were expressed in Escherichia coli and purified. Of these recombinant proteins, only ZmeIF5A-S2A was not phosphorylated by maize CK2. Also, Arabidopsis thaliana and Saccharomyces cerevisiae eIF5A-S2A mutants were not phosphorylated despite effective phosphorylation of wild-type variants. A newly developed method exploiting the specificity of thrombin cleavage was used to confirm that Ser(2) in ZmeIF5A is indeed phosphorylated. To find a role of the Ser(2) phosphorylation, ZmeIF5A and its variants mutated at Ser(2) (S2A and S2D) were transiently expressed in maize protoplasts. The expressed fluorescence labeled proteins were visualized by confocal microscopy. Although wild-type ZmeIF5A and its S2A variant were distributed evenly between the nucleus and cytoplasm, the variant with Ser(2) replaced by aspartic acid, which mimics a phosphorylated serine, was sequestered in the nucleus. These results suggests that phosphorylation of Ser(2) plays a role in regulation of nucleocytoplasmic shuttling of eIF5A in plant cells.
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Affiliation(s)
- Maja Łebska
- From the Institute of Biochemistry and Biophysics, Polish Academy of Science, Pawińskiego 5a, 02-106 Warsaw, Poland
| | - Arkadiusz Ciesielski
- From the Institute of Biochemistry and Biophysics, Polish Academy of Science, Pawińskiego 5a, 02-106 Warsaw, Poland
| | - Lidia Szymona
- From the Institute of Biochemistry and Biophysics, Polish Academy of Science, Pawińskiego 5a, 02-106 Warsaw, Poland
| | - Luiza Godecka
- From the Institute of Biochemistry and Biophysics, Polish Academy of Science, Pawińskiego 5a, 02-106 Warsaw, Poland
| | | | - Jadwiga Szczegielniak
- From the Institute of Biochemistry and Biophysics, Polish Academy of Science, Pawińskiego 5a, 02-106 Warsaw, Poland
| | - Grażyna Muszyńska
- From the Institute of Biochemistry and Biophysics, Polish Academy of Science, Pawińskiego 5a, 02-106 Warsaw, Poland
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Ogiso E, Takahashi Y, Sasaki T, Yano M, Izawa T. The role of casein kinase II in flowering time regulation has diversified during evolution. PLANT PHYSIOLOGY 2010; 152:808-20. [PMID: 20007447 PMCID: PMC2815897 DOI: 10.1104/pp.109.148908] [Citation(s) in RCA: 86] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/06/2009] [Accepted: 12/02/2009] [Indexed: 05/17/2023]
Abstract
Casein kinase II (CK2) is a protein kinase with an evolutionarily conserved function as a circadian clock component in several organisms, including the long-day plant Arabidopsis (Arabidopsis thaliana). The circadian clock component CIRCADIAN CLOCK ASSOCIATED1 (CCA1) is a CK2 target in Arabidopsis, where it influences photoperiodic flowering. In rice (Oryza sativa), a short-day plant, Heading date6 (Hd6) encodes a CK2alpha subunit that delays flowering time under long-day conditions. Here, we demonstrate that control of flowering time in rice by the Hd6 CK2alpha subunit requires a functional Hd1 gene (an Arabidopsis CONSTANS ortholog) and is independent of the circadian clock mechanism. Our findings from overexpressing the dominant-negative CK2 allele in rice support the independence of CK2 function from the circadian clock. This lack of control of the circadian clock by Hd6 CK2alpha might be due to the presence of glutamate in OsLHY (a CCA1 ortholog in rice) instead of the serine at the corresponding CK2 target site in CCA1. However, this glutamate is critical for the control of the OsPRR1 gene (a rice ortholog of the Arabidopsis TOC1/PRR1 gene) by OsLHY for regulation of the circadian clock. We also demonstrated that the other conserved CK2 target sites in OsLHY conferred robust rhythmic expression of OsLHY-LUC under diurnal conditions. These findings imply that the role of CK2 in flowering-time regulation in higher plants has diversified during evolution.
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