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Pham G, Shin DM, Kim Y, Kim SH. Ran-GTP/-GDP-dependent nuclear accumulation of NONEXPRESSOR OF PATHOGENESIS-RELATED GENES1 and TGACG-BINDING FACTOR2 controls salicylic acid-induced leaf senescence. PLANT PHYSIOLOGY 2022; 189:1774-1793. [PMID: 35417014 PMCID: PMC9237681 DOI: 10.1093/plphys/kiac164] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2021] [Accepted: 02/08/2022] [Indexed: 05/11/2023]
Abstract
Leaf senescence is the final stage of leaf development and can be triggered by various external factors, such as hormones and light deprivation. In this study, we demonstrate that the overexpression of the GTP-bound form of Arabidopsis (Arabidopsis thaliana) Ran1 (a Ras-related nuclear small G-protein, AtRan1) efficiently promotes age-dependent and dark-triggered leaf senescence, while Ran-GDP has the opposite effect. Transcriptome analysis comparing AtRan1-GDP- and AtRan1-GTP-overexpressing transgenic plants (Ran1T27Nox and Ran1G22Vox, respectively) revealed that differentially expressed genes (DEGs) related to the senescence-promoting hormones salicylic acid (SA), jasmonic acid, abscisic acid, and ethylene (ET) were significantly upregulated in dark-triggered senescing leaves of Ran1G22Vox, indicating that these hormones are actively involved in Ran-GTP/-GDP-dependent, dark-triggered leaf senescence. Bioinformatic analysis of the promoter regions of DEGs identified diverse consensus motifs, including the bZIP motif, a common binding site for TGACG-BINDING FACTOR (TGA) transcription factors. Interestingly, TGA2 and its interactor, NONEXPRESSOR OF PATHOGENESIS-RELATED GENES1 (NPR1), which are two positive transcriptional regulators of SA signaling, differed in their extent of accumulation in the nucleus versus cytoplasm of Ran1T27Nox and Ran1G22Vox plants. Moreover, SA-induced, Ran-GTP-/-GDP-dependent functions of NPR1 included genome-wide global transcriptional reprogramming of genes involved in cell death, aging, and chloroplast organization. Furthermore, the expression of AtRan1-GTP in SA signaling-defective npr1 and SA biosynthesis-deficient SA-induction deficient2 genetic backgrounds abolished the effects of AtRan1-GTP, thus retarding age-promoted leaf senescence. However, ET-induced leaf senescence was not mediated by Ran machinery-dependent nuclear shuttling of ETHYLENE-INSENSITIVE3 and ETHYLENE-INSENSITIVE3-LIKE1 proteins. We conclude that Ran-GTP/-GDP-dependent nuclear accumulation of NPR1 and TGA2 represents another regulatory node for SA-induced leaf senescence.
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Affiliation(s)
| | | | - Yoon Kim
- Division of Biological Science and Technology, Yonsei University, Yonseidae 1 Gil, Wonju-Si 220-710, South Korea
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Kim Y, Song JH, Park SU, Jeong YS, Kim SH. Brassinosteroid-Induced Transcriptional Repression and Dephosphorylation-Dependent Protein Degradation Negatively Regulate BIN2-Interacting AIF2 (a BR Signaling-Negative Regulator) bHLH Transcription Factor. PLANT & CELL PHYSIOLOGY 2017; 58:227-239. [PMID: 28069895 DOI: 10.1093/pcp/pcw223] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2016] [Accepted: 12/12/2016] [Indexed: 05/19/2023]
Abstract
Brassinosteroids (BRs) are plant polyhydroxy-steroids that play important roles in plant growth and development via extensive signal integration through direct interactions between regulatory components of different signaling pathways. Recent studies have shown that diverse helix-loop-helix/basic helix-loop-helix (HLH/bHLH) family proteins are actively involved in control of BR signaling pathways and interact with other signaling pathways. In this study, we show that ATBS1-INTERACTING FACTOR 2 (AIF2), a nuclear-localized atypical bHLH transcription factor, specifically interacts with BRASSINOSTEROID-INSENSITIVE 2 (BIN2) among other BR signaling molecules. Overexpression of AIF2 down-regulated transcript expression of growth-promoting genes, thus resulting in retardation of growth. AIF2 renders plants hyposensitive to BR-induced root growth inhibition, but shows little effects on BR-promoted hypocotyl elongation. Notably, AIF2 was dephosphorylated by BR, and the dephosphorylated AIF2 was subject to proteasome-mediated degradation. AIF2 degradation was greatly induced by BR and ABA, but relatively slightly by other hormones such as auxin, gibberellin, cytokinin and ethylene. Moreover, AIF2 transcription was significantly suppressed by a BRI1/BZR1-mediated BR signaling pathway through a direct binding of BRASSINAZOLE RESISTANT 1 (BZR1) to the BR response element (BRRE) region of the AIF2 promoter. In conclusion, our study suggests that BIN2-driven AIF2 phosphorylation could augment the BIN2/AIF2-mediated negative circuit of BR signaling pathways, and the BR-induced transcriptional repression and protein degradation negatively regulate AIF2 transcription factor, reinforcing the BZR1/BES1-mediated positive BR signaling pathway.
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Affiliation(s)
- Yoon Kim
- Division of Biological Science and Technology, Yonsei University, Wonju, Korea
| | - Ji-Hye Song
- Division of Biological Science and Technology, Yonsei University, Wonju, Korea
| | - Seon-U Park
- Division of Biological Science and Technology, Yonsei University, Wonju, Korea
| | - You-Seung Jeong
- Division of Biological Science and Technology, Yonsei University, Wonju, Korea
| | - Soo-Hwan Kim
- Division of Biological Science and Technology, Yonsei University, Wonju, Korea
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Takahashi Y, Kinoshita T, Matsumoto M, Shimazaki KI. Inhibition of the Arabidopsis bHLH transcription factor by monomerization through abscisic acid-induced phosphorylation. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2016; 87:559-567. [PMID: 27227462 DOI: 10.1111/tpj.13217] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/19/2015] [Accepted: 05/13/2016] [Indexed: 06/05/2023]
Abstract
We have demonstrated that the Arabidopsis basic helix-loop-helix (bHLH) transcription factor, ABA-responsive kinase substrate 1 (AKS1; also known as FLOWERING BHLH 3, FBH3), enhances K(+) channel expression in guard cells leading to stomatal opening. The expression is suppressed by ABA-induced phosphorylation of AKS1. Here we show that the phosphorylation results in the monomerization of AKS1 multimers and inhibits AKS1 binding to DNA. AKS1 forms homo-multimers which dissociate following phosphorylation. Replacement of a critical amino acid in the bHLH domain inhibited multimer formation and decreased the binding of AKS1 to DNA. The monomerization was elicited via phosphorylation at three serine residues, which is mediated by SNF1-related protein kinase 2.6 (SnRK2.6), in the vicinity of bHLH domain. Furthermore, ABA induced the phosphorylation-dependent release of AKS1 from DNA, thereby suppressing transcriptional activity in vivo. Our results document a mechanism that inhibits gene expression by phosphorylation of a bHLH transcription factor.
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Affiliation(s)
- Yohei Takahashi
- Department of Biology, Faculty of Sciences, Kyushu University, Fukuoka, 812-8581, Japan
- Division of Biological Science, Graduate School of Science, Nagoya University, Nagoya, 464-8602, Japan
| | - Toshinori Kinoshita
- Division of Biological Science, Graduate School of Science, Nagoya University, Nagoya, 464-8602, Japan
- Institute of Transformative Bio-Molecules (WPI-ITbM), Nagoya University, Nagoya, 464-8602, Japan
| | - Masaki Matsumoto
- Department of Molecular and Cellular Biology, Medical Institute of Bioregulation, Kyushu University, Maidashi, Fukuoka, 812-8582, Japan
| | - Ken-Ichiro Shimazaki
- Department of Biology, Faculty of Sciences, Kyushu University, Fukuoka, 812-8581, Japan.
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Gu Y, Zebell SG, Liang Z, Wang S, Kang BH, Dong X. Nuclear Pore Permeabilization Is a Convergent Signaling Event in Effector-Triggered Immunity. Cell 2016; 166:1526-1538.e11. [PMID: 27569911 DOI: 10.1016/j.cell.2016.07.042] [Citation(s) in RCA: 94] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2016] [Revised: 06/15/2016] [Accepted: 07/26/2016] [Indexed: 01/06/2023]
Abstract
Nuclear transport of immune receptors, signal transducers, and transcription factors is an essential regulatory mechanism for immune activation. Whether and how this process is regulated at the level of the nuclear pore complex (NPC) remains unclear. Here, we report that CPR5, which plays a key inhibitory role in effector-triggered immunity (ETI) and programmed cell death (PCD) in plants, is a novel transmembrane nucleoporin. CPR5 associates with anchors of the NPC selective barrier to constrain nuclear access of signaling cargos and sequesters cyclin-dependent kinase inhibitors (CKIs) involved in ETI signal transduction. Upon activation by immunoreceptors, CPR5 undergoes an oligomer to monomer conformational switch, which coordinates CKI release for ETI signaling and reconfigures the selective barrier to allow significant influx of nuclear signaling cargos through the NPC. Consequently, these coordinated NPC actions result in simultaneous activation of diverse stress-related signaling pathways and constitute an essential regulatory mechanism specific for ETI/PCD induction.
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Affiliation(s)
- Yangnan Gu
- Department of Biology, Howard Hughes Medical Institute-Gordon and Betty Moore Foundation, P.O. Box 90338, Duke University, Durham, NC 27708, USA
| | - Sophia G Zebell
- Department of Biology, Howard Hughes Medical Institute-Gordon and Betty Moore Foundation, P.O. Box 90338, Duke University, Durham, NC 27708, USA
| | - Zizhen Liang
- School of Life Sciences, Center for Cell and Developmental Biology and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Hong Kong, China
| | - Shui Wang
- Development Center of Plant Germplasm Resources, College of Life and Environmental Sciences, Shanghai Normal University, Shanghai 200234, China
| | - Byung-Ho Kang
- School of Life Sciences, Center for Cell and Developmental Biology and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Hong Kong, China
| | - Xinnian Dong
- Department of Biology, Howard Hughes Medical Institute-Gordon and Betty Moore Foundation, P.O. Box 90338, Duke University, Durham, NC 27708, USA.
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Ras-Related Nuclear Protein Ran3B Gene Is Involved in Hormone Responses in the Embryogenic Callus of Dimocarpus longan Lour. Int J Mol Sci 2016; 17:ijms17060873. [PMID: 27271605 PMCID: PMC4926407 DOI: 10.3390/ijms17060873] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2016] [Revised: 05/15/2016] [Accepted: 05/23/2016] [Indexed: 11/17/2022] Open
Abstract
Ras-related guanosine triphosphate (GTP)-binding nuclear protein (Ran) GTPases function as molecular switches and regulate diverse cellular events in eukaryotes. Our previous work suggested that DlRan3B is active during longan (Dimocarpus longan Lour.) somatic embryogenesis (SE) processes. Herein, subcellular localization of DlRan3B was found to be localized in the nucleus and expression profiling of DlRan3B was performed during longan SE and after exposure to plant hormones (indoleacetic acid (IAA), gibberellin A3 (GA3), salicylic acid (SA), methyl jasmonte (MeJA), and abscisic acid (ABA)). We cloned and sequenced 1569 bp of 5′-flanking sequence of DlRan3B (GenBank: JQ279697). Bioinformatic analysis indicated that the promoter contained plant hormone-related regulatory elements. Deletion analysis and responses to hormones identified stimulative and repressive regulatory elements in the DlRan3B promoter. The key elements included those responding to auxin, gibberellin, SA, MeJA, and ABA. DlRan3B was located in the nucleus and accumulated in the late stage of longan SE. The expression of DlRan3B was significantly induced by IAA, GA3, and ABA, but suppressed by SA and MeJA. Promoter transcription was induced by IAA and GA3, but suppressed by SA. Thus, DlRan3B might participate in auxin, gibberellin, and ABA responses during longan late SE, and DlRan3B is involved in phytohormone responsiveness.
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Boeglin M, Fuglsang AT, Luu DT, Sentenac H, Gaillard I, Chérel I. Reduced expression of AtNUP62 nucleoporin gene affects auxin response in Arabidopsis. BMC PLANT BIOLOGY 2016; 16:2. [PMID: 26728150 PMCID: PMC4700657 DOI: 10.1186/s12870-015-0695-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/13/2015] [Accepted: 12/17/2015] [Indexed: 05/29/2023]
Abstract
BACKGROUND The plant nuclear pore complex has strongly attracted the attention of the scientific community during the past few years, in particular because of its involvement in hormonal and pathogen/symbiotic signalling. In Arabidopsis thaliana, more than 30 nucleoporins have been identified, but only a few of them have been characterized. Among these, AtNUP160, AtNUP96, AtNUP58, and AtTPR have been reported to modulate auxin signalling, since corresponding mutants are suppressors of the auxin resistance conferred by the axr1 (auxin-resistant) mutation. The present work is focused on AtNUP62, which is essential for embryo and plant development. This protein is one of the three nucleoporins (with AtNUP54 and AtNUP58) of the central channel of the nuclear pore complex. RESULTS AtNUP62 promoter activity was detected in many organs, and particularly in the embryo sac, young germinating seedlings and at the adult stage in stipules of cauline leaves. The atnup62-1 mutant, harbouring a T-DNA insertion in intron 5, was identified as a knock-down mutant. It displayed developmental phenotypes that suggested defects in auxin transport or responsiveness. Atnup62 mutant plantlets were found to be hypersensitive to auxin, at the cotyledon and root levels. The phenotype of the AtNUP62-GFP overexpressing line further supported the existence of a link between AtNUP62 and auxin signalling. Furthermore, the atnup62 mutation led to an increase in the activity of the DR5 auxin-responsive promoter, and suppressed the auxin-resistant root growth and leaf serration phenotypes of the axr1 mutant. CONCLUSION AtNUP62 appears to be a major negative regulator of auxin signalling. Auxin hypersensitivity of the atnup62 mutant, reminding that of atnup58 (and not observed with other nucleoporin mutants), is in agreement with the reported interaction between AtNUP62 and AtNUP58 proteins, and suggests closely related functions. The effect of AtNUP62 on auxin signalling likely occurs in relation to scaffold proteins of the nuclear pore complex (AtNUP160, AtNUP96 and AtTPR).
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Affiliation(s)
- Martin Boeglin
- Biochimie et Physiologie Moléculaire des Plantes, CNRS/INRA/SupAgro/UM2, 2 place Viala, 34060, Montpellier cedex, France.
| | - Anja Thoe Fuglsang
- Biochimie et Physiologie Moléculaire des Plantes, CNRS/INRA/SupAgro/UM2, 2 place Viala, 34060, Montpellier cedex, France.
- Present address: Plant and Environmental Sciences, Section for Transport Biology, University of Copenhagen, Thorvaldsensvej 40, 1871, Frederiksberg C, Denmark.
| | - Doan-Trung Luu
- Biochimie et Physiologie Moléculaire des Plantes, CNRS/INRA/SupAgro/UM2, 2 place Viala, 34060, Montpellier cedex, France.
| | - Hervé Sentenac
- Biochimie et Physiologie Moléculaire des Plantes, CNRS/INRA/SupAgro/UM2, 2 place Viala, 34060, Montpellier cedex, France.
| | - Isabelle Gaillard
- Biochimie et Physiologie Moléculaire des Plantes, CNRS/INRA/SupAgro/UM2, 2 place Viala, 34060, Montpellier cedex, France.
| | - Isabelle Chérel
- Biochimie et Physiologie Moléculaire des Plantes, CNRS/INRA/SupAgro/UM2, 2 place Viala, 34060, Montpellier cedex, France.
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DlRan3A is involved in hormone, light, and abiotic stress responses in embryogenic callus of Dimocarpus longan Lour. Gene 2015; 569:267-75. [DOI: 10.1016/j.gene.2015.06.013] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2014] [Revised: 05/11/2015] [Accepted: 05/27/2015] [Indexed: 12/21/2022]
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Chatterjee M, Gupta S, Bhar A, Chakraborti D, Basu D, Das S. Analysis of root proteome unravels differential molecular responses during compatible and incompatible interaction between chickpea (Cicer arietinum L.) and Fusarium oxysporum f. sp. ciceri Race1 (Foc1). BMC Genomics 2014; 15:949. [PMID: 25363865 PMCID: PMC4237293 DOI: 10.1186/1471-2164-15-949] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2014] [Accepted: 10/22/2014] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND Vascular wilt caused by Fusarium oxysporum f. sp. ciceri Race 1 (Foc1) is a serious disease of chickpea (Cicer arietinum L.) accounting for approximately 10-15% annual crop loss. The fungus invades the plant via roots, colonizes the xylem vessels and prevents the upward translocation of water and nutrients, finally resulting in wilting of the entire plant. Although comparative transcriptomic profiling have highlighted some important signaling molecules, but proteomic studies involving chickpea-Foc1 are limited. The present study focuses on comparative root proteomics of susceptible (JG62) and resistant (WR315) chickpea genotypes infected with Foc1, to understand the mechanistic basis of susceptibility and/or resistance. RESULTS The differential and unique proteins of both genotypes were identified at 48 h, 72 h, and 96 h post Foc1 inoculation. 2D PAGE analyses followed by MALDI-TOF MS and MS/MS identified 100 differentially (>1.5 fold<, p<0.05) or uniquely expressed proteins. These proteins were further categorized into 10 functional classes and grouped into GO (gene ontology) categories. Network analyses of identified proteins revealed intra and inter relationship of these proteins with their neighbors as well as their association with different defense signaling pathways. qRT-PCR analyses were performed to correlate the mRNA and protein levels of some proteins of representative classes. CONCLUSIONS The differential and unique proteins identified indicate their involvement in early defense signaling of the host. Comparative analyses of expression profiles of obtained proteins suggest that albeit some common components participate in early defense signaling in both susceptible and resistant genotypes, but their roles and regulation differ in case of compatible and/or incompatible interactions. Thus, functional characterization of identified PR proteins (PR1, BGL2, TLP), Trypsin protease inhibitor, ABA responsive protein, cysteine protease, protein disulphide isomerase, ripening related protein and albumins are expected to serve as important molecular components for biotechnological application and development of sustainable resistance against Foc1.
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Affiliation(s)
- Moniya Chatterjee
- />Division of Plant Biology, Bose Institute, Centenary Campus, P 1/12, CIT Scheme, VII-M, Kankurgachi, Kolkata, 700054 West Bengal India
| | - Sumanti Gupta
- />Division of Plant Biology, Bose Institute, Centenary Campus, P 1/12, CIT Scheme, VII-M, Kankurgachi, Kolkata, 700054 West Bengal India
| | - Anirban Bhar
- />Division of Plant Biology, Bose Institute, Centenary Campus, P 1/12, CIT Scheme, VII-M, Kankurgachi, Kolkata, 700054 West Bengal India
| | - Dipankar Chakraborti
- />Post Graduate Department of Biotechnology, St. Xavier’s College (Autonomous), 30 Park Street, Kolkata, 700016 India
| | - Debabrata Basu
- />Division of Plant Biology, Bose Institute, Centenary Campus, P 1/12, CIT Scheme, VII-M, Kankurgachi, Kolkata, 700054 West Bengal India
| | - Sampa Das
- />Division of Plant Biology, Bose Institute, Centenary Campus, P 1/12, CIT Scheme, VII-M, Kankurgachi, Kolkata, 700054 West Bengal India
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Parry G. Assessing the function of the plant nuclear pore complex and the search for specificity. JOURNAL OF EXPERIMENTAL BOTANY 2013; 64:833-45. [PMID: 23077202 DOI: 10.1093/jxb/ers289] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Plant cells encounter a wide variety of molecules that influence their gene expression and development. A key component of most signal transduction pathways involves the regulated movement of molecules into and out of the nucleus. The plant nuclear pore complex (NPC) is a critical controlling element in this nucleocytoplasmic movement of protein and RNA. The NPC is comprised of approximately 30 nucleoporin proteins arranged in radial symmetry around the central pore. Over recent years our understanding of how the NPC impacts different signalling pathways has increased following the identification of a range of nucleoporin mutant plants. These mutants allow us to gain insight into how the response to hormonal, abiotic, and biotic stresses are effected by changes in nuclear transport. Importantly we have little information regarding the specific molecules whose nuclear transport is altered in these processes and the identification of these proteins is a significant challenge. Here is presented an overview as to how the members of the plant NPC affect signalling pathways, highlighting the progress and difficulties within this research area.
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Affiliation(s)
- Geraint Parry
- Institute of Integrative Biology, University of Liverpool, Crown Street, Liverpool, UK.
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Mason ME, Koch JL, Krasowski M, Loo J. Comparisons of protein profiles of beech bark disease resistant and susceptible American beech (Fagus grandifolia). Proteome Sci 2013; 11:2. [PMID: 23317283 PMCID: PMC3575302 DOI: 10.1186/1477-5956-11-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2012] [Accepted: 12/23/2012] [Indexed: 11/10/2022] Open
Abstract
UNLABELLED BACKGROUND Beech bark disease is an insect-fungus complex that damages and often kills American beech trees and has major ecological and economic impacts on forests of the northeastern United States and southeastern Canadian forests. The disease begins when exotic beech scale insects feed on the bark of trees, and is followed by infection of damaged bark tissues by one of the Neonectria species of fungi. Proteomic analysis was conducted of beech bark proteins from diseased trees and healthy trees in areas heavily infested with beech bark disease. All of the diseased trees had signs of Neonectria infection such as cankers or fruiting bodies. In previous tests reported elsewhere, all of the diseased trees were demonstrated to be susceptible to the scale insect and all of the healthy trees were demonstrated to be resistant to the scale insect. Sixteen trees were sampled from eight geographically isolated stands, the sample consisting of 10 healthy (scale-resistant) and 6 diseased/infested (scale-susceptible) trees. RESULTS Proteins were extracted from each tree and analysed in triplicate by isoelectric focusing followed by denaturing gel electrophoresis. Gels were stained and protein spots identified and intensity quantified, then a statistical model was fit to identify significant differences between trees. A subset of BBD differential proteins were analysed by mass spectrometry and matched to known protein sequences for identification. Identified proteins had homology to stress, insect, and pathogen related proteins in other plant systems. Protein spots significantly different in diseased and healthy trees having no stand or disease-by-stand interaction effects were identified. CONCLUSIONS Further study of these proteins should help to understand processes critical to resistance to beech bark disease and to develop biomarkers for use in tree breeding programs and for the selection of resistant trees prior to or in early stages of BBD development in stands. Early identification of resistant trees (prior to the full disease development in an area) will allow forest management through the removal of susceptible trees and their root-sprouts prior to the onset of disease, allowing management and mitigation of costs, economic impact, and impacts on ecological systems and services.
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Affiliation(s)
- Mary E Mason
- US Forest Service, Northern Research Station, 359 Main Rd, Delaware, OH, 43015, USA.
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Graumann K, Bass HW, Parry G. SUNrises on the International Plant Nucleus Consortium: SEB Salzburg 2012. Nucleus 2013; 4:3-7. [PMID: 23324458 DOI: 10.4161/nucl.23385] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
The nuclear periphery is a dynamic, structured environment, whose precise functions are essential for global processes-from nuclear, to cellular, to organismal. Its main components-the nuclear envelope (NE) with inner and outer nuclear membranes (INM and ONM), nuclear pore complexes (NPC), associated cytoskeletal and nucleoskeletal components as well as chromatin are conserved across eukaryotes (Fig. 1). In metazoans in particular, the structure and functions of nuclear periphery components are intensely researched partly because of their involvement in various human diseases. While far less is known about these in plants, the last few years have seen a significant increase in research activity in this area. Plant biologists are not only catching up with the animal field, but recent findings are pushing our advances in this field globally. In recognition of this developing field, the Annual Society of Experimental Biology Meeting in Salzburg kindly hosted a session co-organized by Katja Graumann and David E. Evans (Oxford Brookes University) highlighting new insights into plant nuclear envelope proteins and their interactions. This session brought together leading researchers with expertise in topics such as epigenetics, meiosis, nuclear pore structure and functions, nucleoskeleton and nuclear envelope composition. An open and friendly exchange of ideas was fundamental to the success of the meeting, which resulted in founding the International Plant Nucleus Consortium. This review highlights new developments in plant nuclear envelope research presented at the conference and their importance for the wider understanding of metazoan, yeast and plant nuclear envelope functions and properties.
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Affiliation(s)
- Katja Graumann
- Plant Nuclear Envelope Group, Department of Biological and Medical Sciences, Oxford Brookes University, Oxford, UK
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Rand K, Kobrinsky-Aaronowitz I, Levy Y, Shaul O, Aloni R, Gafni Y. Induction of karyopherin α1 expression by indole-3-acetic acid in auxin-treated or overproducing tobacco plants. PLANT SIGNALING & BEHAVIOR 2011; 6:815-20. [PMID: 21646869 PMCID: PMC3218478 DOI: 10.4161/psb.6.6.14719] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2010] [Revised: 01/04/2011] [Accepted: 01/04/2011] [Indexed: 05/21/2023]
Abstract
Macromolecules may transfer between the cytoplasm and the nucleus only through specific gates - the nuclear pore complexes (NPCs). Translocation of nucleic acids and large proteins requires the presence of a nuclear localization signal (NLS) within the transported molecule. This NLS is recognized by a class of soluble transport receptors termed karyopherins α and beta. We previously characterized the expression pattern of the tomato karyopherin α 1 (LeKAPα1) promoter in transformed tobacco plants. Expression of LeKAPα1 was mainly observed in growing tissues where cell division and extension is rapid. The expression pattern of LeKAPα1 resembled that of auxin-responsive genes. This led us to suggest that auxin participates in the regulation of LeKAPα1 expression. Here we characterized the correlation between auxin level and the activity of the LeKAPα1 promoter. To this end, transgenic tobacco plants carrying the GUS reporter gene under the control of the LeKAPα1 promoter were treated with various levels of exogenous auxin. We also studied transgenic plants in which we increased the endogenous levels of auxin. For this, we expressed in plants both the LeKAPα1 promoter-GUS reporter and the Agrobacterium tumefaciens iaaM gene, which increases the endogenous levels of auxin. The results indicate that the auxin indole-3-acetic acid (IAA) can induce LeKAPα1 expression. We also identified that the sites and levels of LeKAPα1 expression correlated with the endogenous pathways of polar auxin transport.
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Affiliation(s)
- Karin Rand
- Institute of Plant Sciences; Agricultural Research Organization; Bet Dagan, Israel
- Department of Plant Sciences; Tel Aviv University; Tel Aviv, Israel
| | - Irina Kobrinsky-Aaronowitz
- Institute of Plant Sciences; Agricultural Research Organization; Bet Dagan, Israel
- The Mina and Everard Goodman Faculty of Life Sciences; Bar-Ilan University; Ramat-Gan, Israel
| | - Yael Levy
- Institute of Plant Sciences; Agricultural Research Organization; Bet Dagan, Israel
| | - Orit Shaul
- The Mina and Everard Goodman Faculty of Life Sciences; Bar-Ilan University; Ramat-Gan, Israel
| | - Roni Aloni
- Department of Plant Sciences; Tel Aviv University; Tel Aviv, Israel
| | - Yedidya Gafni
- Institute of Plant Sciences; Agricultural Research Organization; Bet Dagan, Israel
- The Mina and Everard Goodman Faculty of Life Sciences; Bar-Ilan University; Ramat-Gan, Israel
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Rodrigues SP, Ventura JA, Aguilar C, Nakayasu ES, Almeida IC, Fernandes PMB, Zingali RB. Proteomic analysis of papaya (Carica papaya L.) displaying typical sticky disease symptoms. Proteomics 2011; 11:2592-602. [DOI: 10.1002/pmic.201000757] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2010] [Revised: 03/14/2011] [Accepted: 03/28/2011] [Indexed: 01/13/2023]
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Punwani JA, Hutchison CE, Schaller GE, Kieber JJ. The subcellular distribution of the Arabidopsis histidine phosphotransfer proteins is independent of cytokinin signaling. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2010; 62:473-82. [PMID: 20136728 DOI: 10.1111/j.1365-313x.2010.04165.x] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Cytokinins are a class of mitogenic plant hormones that play an important role in most aspects of plant development, including shoot and root growth, vascular and photomorphogenic development and leaf senescence. A model for cytokinin perception and signaling has emerged that is similar to bacterial two-component phosphorelays. In this model, binding of cytokinin to the extracellular domain of the Arabidopsis histidine kinase (AHKs) receptors induces autophosphorylation within the intracellular histidine-kinase domain. The phosphoryl group is subsequently transferred to cytosolic Arabidopsis histidine phosphotransfer proteins (AHPs), which have been suggested to translocate to the nucleus in response to cytokinin treatment, where they then transfer the phosphoryl group to nuclear-localized response regulators (Type-A and Type-B ARRs). We examined the effects of cytokinin on AHP subcellular localization in Arabidopsis and, contrary to expectations, the AHPs maintained a constant nuclear/cytosolic distribution following cytokinin treatment. Furthermore, mutation of the conserved phosphoacceptor histidine residue of the AHP, as well as disruption of multiple cytokinin signaling elements, did not affect the subcellular localization of the AHP proteins. Finally, we present data indicating that AHPs maintain a nuclear/cytosolic distribution by balancing active transport into and out of the nucleus. Our findings suggest that the current models indicating relocalization of AHP protein into the nucleus in response to cytokinin are incorrect. Rather, AHPs actively maintain a consistent nuclear/cytosolic distribution regardless of the status of the cytokinin response pathway.
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Affiliation(s)
- Jayson A Punwani
- Department of Biology, University of North Carolina, CB #3280, Chapel Hill, NC 27599-3280, USA
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Huang JG, Yang M, Liu P, Yang GD, Wu CA, Zheng CC. Genome-wide profiling of developmental, hormonal or environmental responsiveness of the nucleocytoplasmic transport receptors in Arabidopsis. Gene 2010; 451:38-44. [DOI: 10.1016/j.gene.2009.11.009] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2009] [Revised: 10/23/2009] [Accepted: 11/17/2009] [Indexed: 12/17/2022]
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Endres MW, Gregory BD, Gao Z, Foreman AW, Mlotshwa S, Ge X, Pruss GJ, Ecker JR, Bowman LH, Vance V. Two plant viral suppressors of silencing require the ethylene-inducible host transcription factor RAV2 to block RNA silencing. PLoS Pathog 2010; 6:e1000729. [PMID: 20084269 PMCID: PMC2800190 DOI: 10.1371/journal.ppat.1000729] [Citation(s) in RCA: 103] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2009] [Accepted: 12/15/2009] [Indexed: 12/11/2022] Open
Abstract
RNA silencing is a highly conserved pathway in the network of interconnected defense responses that are activated during viral infection. As a counter-defense, many plant viruses encode proteins that block silencing, often also interfering with endogenous small RNA pathways. However, the mechanism of action of viral suppressors is not well understood and the role of host factors in the process is just beginning to emerge. Here we report that the ethylene-inducible transcription factor RAV2 is required for suppression of RNA silencing by two unrelated plant viral proteins, potyvirus HC-Pro and carmovirus P38. Using a hairpin transgene silencing system, we find that both viral suppressors require RAV2 to block the activity of primary siRNAs, whereas suppression of transitive silencing is RAV2-independent. RAV2 is also required for many HC-Pro-mediated morphological anomalies in transgenic plants, but not for the associated defects in the microRNA pathway. Whole genome tiling microarray experiments demonstrate that expression of genes known to be required for silencing is unchanged in HC-Pro plants, whereas a striking number of genes involved in other biotic and abiotic stress responses are induced, many in a RAV2-dependent manner. Among the genes that require RAV2 for induction by HC-Pro are FRY1 and CML38, genes implicated as endogenous suppressors of silencing. These findings raise the intriguing possibility that HC-Pro-suppression of silencing is not caused by decreased expression of genes that are required for silencing, but instead, by induction of stress and defense responses, some components of which interfere with antiviral silencing. Furthermore, the observation that two unrelated viral suppressors require the activity of the same factor to block silencing suggests that RAV2 represents a control point that can be readily subverted by viruses to block antiviral silencing. RNA silencing is an important antiviral defense in plants, and many plant viruses encode proteins that block RNA silencing. However, the mechanism of action of the viral suppressors is complex, and little is known about the role of host plant proteins in the process. Here we report the first example of a host protein that plays a required role in viral suppression of silencing—a transcription factor called RAV2 that is required for suppression of silencing by two different and unrelated viral proteins. Analysis of plant gene expression patterns shows that RAV2 is required for induction of many genes involved in other stress and defense pathways, including genes implicated as plant suppressors of silencing. Overall, the results suggest that RAV2 is an important factor in viral suppression of silencing and that the role of RAV2 is to divert host defenses toward responses that interfere with antiviral silencing.
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Affiliation(s)
- Matthew W. Endres
- Department of Biological Sciences, University of South Carolina, Columbia, South Carolina, United States of America
| | - Brian D. Gregory
- Plant Biology Laboratory, The Salk Institute for Biological Studies, La Jolla, California, United States of America
- Genomic Analysis Laboratory, The Salk Institute for Biological Studies, La Jolla, California, United States of America
| | - Zhihuan Gao
- Department of Biological Sciences, University of South Carolina, Columbia, South Carolina, United States of America
| | - Amy Wahba Foreman
- Department of Biological Sciences, University of South Carolina, Columbia, South Carolina, United States of America
| | - Sizolwenkosi Mlotshwa
- Department of Biological Sciences, University of South Carolina, Columbia, South Carolina, United States of America
| | - Xin Ge
- Department of Biological Sciences, University of South Carolina, Columbia, South Carolina, United States of America
| | - Gail J. Pruss
- Department of Biological Sciences, University of South Carolina, Columbia, South Carolina, United States of America
| | - Joseph R. Ecker
- Plant Biology Laboratory, The Salk Institute for Biological Studies, La Jolla, California, United States of America
- Genomic Analysis Laboratory, The Salk Institute for Biological Studies, La Jolla, California, United States of America
- * E-mail: (JRE) (JE); (LHB) (LB); (VV) (VV)
| | - Lewis H. Bowman
- Department of Biological Sciences, University of South Carolina, Columbia, South Carolina, United States of America
- * E-mail: (JRE) (JE); (LHB) (LB); (VV) (VV)
| | - Vicki Vance
- Department of Biological Sciences, University of South Carolina, Columbia, South Carolina, United States of America
- * E-mail: (JRE) (JE); (LHB) (LB); (VV) (VV)
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Meier I, Brkljacic J. The Arabidopsis nuclear pore and nuclear envelope. THE ARABIDOPSIS BOOK 2010; 8:e0139. [PMID: 22303264 PMCID: PMC3244964 DOI: 10.1199/tab.0139] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
The nuclear envelope is a double membrane structure that separates the eukaryotic cytoplasm from the nucleoplasm. The nuclear pores embedded in the nuclear envelope are the sole gateways for macromolecular trafficking in and out of the nucleus. The nuclear pore complexes assembled at the nuclear pores are large protein conglomerates composed of multiple units of about 30 different nucleoporins. Proteins and RNAs traffic through the nuclear pore complexes, enabled by the interacting activities of nuclear transport receptors, nucleoporins, and elements of the Ran GTPase cycle. In addition to directional and possibly selective protein and RNA nuclear import and export, the nuclear pore gains increasing prominence as a spatial organizer of cellular processes, such as sumoylation and desumoylation. Individual nucleoporins and whole nuclear pore subcomplexes traffic to specific mitotic locations and have mitotic functions, for example at the kinetochores, in spindle assembly, and in conjunction with the checkpoints. Mutants of nucleoporin genes and genes of nuclear transport components lead to a wide array of defects from human diseases to compromised plant defense responses. The nuclear envelope acts as a repository of calcium, and its inner membrane is populated by functionally unique proteins connected to both chromatin and-through the nuclear envelope lumen-the cytoplasmic cytoskeleton. Plant nuclear pore and nuclear envelope research-predominantly focusing on Arabidopsis as a model-is discovering both similarities and surprisingly unique aspects compared to the more mature model systems. This chapter gives an overview of our current knowledge in the field and of exciting areas awaiting further exploration.
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Affiliation(s)
- Iris Meier
- Department of Plant Cellular and Molecular Biology and Plant Biotechnology Center, The Ohio State University, 520 Aronoff Laboratory, 318 W 12th Avenue, Columbus, OH 43210
- Address correspondence to
| | - Jelena Brkljacic
- Department of Plant Cellular and Molecular Biology and Plant Biotechnology Center, The Ohio State University, 520 Aronoff Laboratory, 318 W 12th Avenue, Columbus, OH 43210
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Schenkluhn L, Hohnjec N, Niehaus K, Schmitz U, Colditz F. Differential gel electrophoresis (DIGE) to quantitatively monitor early symbiosis- and pathogenesis-induced changes of the Medicago truncatula root proteome. J Proteomics 2009; 73:753-68. [PMID: 19895911 DOI: 10.1016/j.jprot.2009.10.009] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2009] [Revised: 10/20/2009] [Accepted: 10/23/2009] [Indexed: 01/19/2023]
Abstract
Symbiosis- and pathogenesis-related early protein induction patterns in the model legume Medicago truncatula were analysed with two-dimensional differential gel electrophoresis. Two symbiotic soil microorganisms (Glomus intraradices, Sinorhizobium meliloti) were used in single infections and in combination with a secondary pathogenic infection by the oomycete Aphanomyces euteiches. Proteomic analyses performed 6 and 24h after inoculations led to identification of 87 differentially induced proteins which likely represent the M. truncatula root 'interactome'. A set of proteins involved in a primary antioxidant defense reaction was detected during all associations investigated. Symbiosis-related protein induction includes a typical factor of early symbiosis-specific signalling (CaM-2), two Ran-binding proteins of nucleocytoplasmic signalling, and a set of energy-related enzymes together with proteins involved in symbiosis-initiated C- and N-fixation. Pathogen-associated protein induction consists of mainly PR proteins, Kunitz-type proteinase inhibitors, a lectin, and proteins related to primary carbohydrate metabolism and phytoalexin synthesis. Absence of PR proteins and decreased pathogen-induced protein patterns during mixed symbiotic and pathogenic infections indicate bioprotective effects due to symbiotic co-infection. Several 14-3-3 proteins were found as predominant proteins during mixed infections. With respect to hormone-regulation, A. euteiches infection led to induction of ABA-related pathways, while auxin-related pathways are induced during symbiosis.
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Affiliation(s)
- Leif Schenkluhn
- University of Bielefeld, Dept. 7, Proteome and Metabolome Research, Universitätsstrasse 25, D-33615 Bielefeld, Germany
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Warner KA, Rudall PJ, Frohlich MW. Environmental control of sepalness and petalness in perianth organs of waterlilies: a new Mosaic theory for the evolutionary origin of a differentiated perianth. JOURNAL OF EXPERIMENTAL BOTANY 2009; 60:3559-74. [PMID: 19574253 PMCID: PMC2724705 DOI: 10.1093/jxb/erp202] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
The conventional concept of an 'undifferentiated perianth', implying that all perianth organs of a flower are alike, obscures the fact that individual perianth organs are sometimes differentiated into sepaloid and petaloid regions, as in the early-divergent angiosperms Nuphar, Nymphaea, and Schisandra. In the waterlilies Nuphar and Nymphaea, sepaloid regions closely coincide with regions of the perianth that were exposed when the flower was in bud, whereas petaloid regions occur in covered regions, suggesting that their development is at least partly controlled by the environment of the developing tepal. Green and colourful areas differ from each other in trichome density and presence of papillae, features that often distinguish sepals and petals. Field experiments to test whether artificial exposure can induce sepalness in the inner tepals showed that development of sepaloid patches is initiated by exposure, at least in the waterlily species examined. Although light is an important environmental cue, other important factors include an absence of surface contact. Our interpretation contradicts the unspoken rule that 'sepal' and 'petal' must refer to whole organs. We propose a novel theory (the Mosaic theory), in which the distinction between sepalness and petalness evolved early in angiosperm history, but these features were not fixed to particular organs and were primarily environmentally controlled. At a later stage in angiosperm evolution, sepaloid and petaloid characteristics became fixed to whole organs in specific whorls, thus reducing or removing the need for environmental control in favour of fixed developmental control.
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Affiliation(s)
- Kate A. Warner
- Department of Botany, The Natural History Museum, Cromwell Road, London SW7 5BD, UK
- Jodrell Laboratory, Royal Botanic Gardens, Kew, Richmond, Surrey TW9 3AB, UK
| | - Paula J. Rudall
- Jodrell Laboratory, Royal Botanic Gardens, Kew, Richmond, Surrey TW9 3AB, UK
| | - Michael W. Frohlich
- Jodrell Laboratory, Royal Botanic Gardens, Kew, Richmond, Surrey TW9 3AB, UK
- To whom correspondence should be addressed:
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