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Schütte D, Baier M, Griebel T. Cold priming on pathogen susceptibility in the Arabidopsis eds1 mutant background requires a functional stromal Ascorbate Peroxidase. Plant Signal Behav 2024; 19:2300239. [PMID: 38170666 PMCID: PMC10766390 DOI: 10.1080/15592324.2023.2300239] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/08/2023] [Accepted: 12/23/2023] [Indexed: 01/05/2024]
Abstract
24 h cold exposure (4°C) is sufficient to reduce pathogen susceptibility in Arabidopsis thaliana against the virulent Pseudomonas syringae pv. tomato (Pst) strain even when the infection occurs five days later. This priming effect is independent of the immune regulator Enhanced Disease Susceptibility 1 (EDS1) and can be observed in the immune-compromised eds1-2 null mutant. In contrast, cold priming-reduced Pst susceptibility is strongly impaired in knock-out lines of the stromal and thylakoid ascorbate peroxidases (sAPX/tAPX) highlighting their relevance for abiotic stress-related increased immune resilience. Here, we extended our analysis by generating an eds1 sapx double mutant. eds1 sapx showed eds1-like resistance and susceptibility phenotypes against Pst strains containing the effectors avrRPM1 and avrRPS4. In comparison to eds1-2, susceptibility against the wildtype Pst strain was constitutively enhanced in eds1 sapx. Although a prior cold priming exposure resulted in reduced Pst titers in eds1-2, it did not alter Pst resistance in eds1 sapx. This demonstrates that the genetic sAPX requirement for cold priming of basal plant immunity applies also to an eds1 null mutant background.
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Affiliation(s)
- Dominic Schütte
- Plant Physiology, Dahlem Centre of Plant Sciences, Freie Universität Berlin, Berlin, Germany
| | - Margarete Baier
- Plant Physiology, Dahlem Centre of Plant Sciences, Freie Universität Berlin, Berlin, Germany
| | - Thomas Griebel
- Plant Physiology, Dahlem Centre of Plant Sciences, Freie Universität Berlin, Berlin, Germany
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2
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Cai H, Xu Y, Yan K, Zhang S, Yang G, Wu C, Zheng C, Huang J. BREVIPEDICELLUS Positively Regulates Salt-Stress Tolerance in Arabidopsis thaliana. Int J Mol Sci 2023; 24. [PMID: 36674568 DOI: 10.3390/ijms24021054] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2022] [Revised: 12/15/2022] [Accepted: 12/31/2022] [Indexed: 01/06/2023] Open
Abstract
Salt stress is one of the major environmental threats to plant growth and development. However, the mechanisms of plants responding to salt stress are not fully understood. Through genetic screening, we identified and characterized a salt-sensitive mutant, ses5 (sensitive to salt 5), in Arabidopsis thaliana. Positional cloning revealed that the decreased salt-tolerance of ses5 was caused by a mutation in the transcription factor BP (BREVIPEDICELLUS). BP regulates various developmental processes in plants. However, the biological function of BP in abiotic stress-signaling and tolerance are still not clear. Compared with wild-type plants, the bp mutant exhibited a much shorter primary-root and lower survival rate under salt treatment, while the BP overexpressors were more tolerant. Further analysis showed that BP could directly bind to the promoter of XTH7 (xyloglucan endotransglucosylase/hydrolase 7) and activate its expression. Resembling the bp mutant, the disruption of XTH7 gave rise to salt sensitivity. These results uncovered novel roles of BP in positively modulating salt-stress tolerance, and illustrated a putative working mechanism.
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3
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Dutta S, Mitra M, Agarwal P, Mahapatra K, De S, Sett U, Roy S. Oxidative and genotoxic damages in plants in response to heavy metal stress and maintenance of genome stability. Plant Signal Behav 2018; 13:e1460048. [PMID: 29621424 PMCID: PMC6149466 DOI: 10.1080/15592324.2018.1460048] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2018] [Accepted: 03/28/2018] [Indexed: 05/17/2023]
Abstract
Plants, being sessile in nature, are constantly exposed to various environmental stresses, such as solar UV radiations, soil salinity, drought and desiccation, rehydration, low and high temperatures and other vast array of air and soil borne chemicals, industrial waste products, metals and metalloids. These agents, either directly or indirectly via the induction of oxidative stress and overproduction of reactive oxygen species (ROS), frequently perturb the chemical or physical structures of DNA and induce both cytotoxic or genotoxic stresses. Such condition, in turn, leads to genome instability and thus eventually severely affecting plant health and crop yield. With the growing industrialization process and non-judicious use of chemical fertilizers, the heavy metal mediated chemical toxicity has become one of the major environmental threats for the plants around the globe. The heavy metal ions cause damage to the structural, enzymatic and non-enzymatic components of plant cell, often resulting in loss of cell viability, thus negatively impacting plant growth and development. Plants have also evolved with an extensive and highly efficient mechanism to respond and adapt under such heavy metal toxicity mediated stress conditions. In addition to morpho-anatomical, hormonal and biochemical responses, at the molecular level, plants respond to heavy metal stress induced oxidative and genotoxic damage via the rapid change in the expression of the responsive genes at the transcriptional level. Various families of transcription factors play crucial role in triggering such responses. Apart from transcriptional response, epigenetic modifications have also been found to be essential for maintenance of plant genome stability under genotoxic stress. This review represents a comprehensive survey of recent advances in our understanding of plant responses to heavy metal mediated toxicity in general with particular emphasis on the transcriptional and epigenetic responses and highlights the importance of understanding the potential targets in the associated pathways for improved stress tolerance in crops.
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Affiliation(s)
- Subhajit Dutta
- Department of Botany, UGC Centre of Advanced Studies, The University of Burdwan, Golapbag campus, Burdwan – 713104, West Bengal, India
| | - Mehali Mitra
- Department of Botany, UGC Centre of Advanced Studies, The University of Burdwan, Golapbag campus, Burdwan – 713104, West Bengal, India
| | - Puja Agarwal
- Department of Botany, UGC Centre of Advanced Studies, The University of Burdwan, Golapbag campus, Burdwan – 713104, West Bengal, India
| | - Kalyan Mahapatra
- Department of Botany, UGC Centre of Advanced Studies, The University of Burdwan, Golapbag campus, Burdwan – 713104, West Bengal, India
| | - Sayanti De
- Department of Botany, UGC Centre of Advanced Studies, The University of Burdwan, Golapbag campus, Burdwan – 713104, West Bengal, India
| | - Upasana Sett
- Department of Botany, UGC Centre of Advanced Studies, The University of Burdwan, Golapbag campus, Burdwan – 713104, West Bengal, India
| | - Sujit Roy
- Department of Botany, UGC Centre of Advanced Studies, The University of Burdwan, Golapbag campus, Burdwan – 713104, West Bengal, India
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Ye ZW, Chen QF, Chye ML. Arabidopsis thaliana Acyl-CoA-binding protein ACBP6 interacts with plasmodesmata-located protein PDLP8. Plant Signal Behav 2017; 12:e1359365. [PMID: 28786767 PMCID: PMC5616145 DOI: 10.1080/15592324.2017.1359365] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2017] [Revised: 07/19/2017] [Accepted: 07/20/2017] [Indexed: 05/22/2023]
Abstract
In Arabidopsis thaliana, six acyl-CoA-binding proteins (ACBPs), designated as AtACBP1 to AtACBP6, have been identified to function in various events related to plant stress and development. The 10-kDa AtACBP6 is the smallest in this protein family, and recombinant AtACBP6 interacts with lipids in vitro by binding to acyl-CoA esters and phosphatidylcholine. Using anti-AtACBP6 antibodies in immunoelectron microscopy, we have localized AtACBP6 in the Arabidopsis phloem. The detection of immunogold grains in the plasmodesmata suggested that AtACBP6 could move from the companion cells to the sieve elements via the plasmodesmata. As AtACBP6 has been identified in a membrane-based interactome analysis to be a potential protein partner of Plasmodesmata-Localized Protein, PDLP8, AtACBP6-PDLP8 interaction was investigated herein utilizing isothermal titration calorimetry, as well as pull-down and bimolecular fluorescence complementation assays (BiFC). Notably, BiFC data revealed that AtACBP6-PDLP8 interaction occurred at the plasma membrane, which was unexpected as AtACBP6 has been previously identified in the cytosol. AtACBP6 expression was generally higher than PDLP8 in β-glucuronidase (GUS) assays on transgenic Arabidopsis transformed with AtACBP6 or PDLP8 promoter-driven GUS, consistent with qRT-PCR and microarray results. Furthermore, western blot analysis using anti-AtACBP6 antibodies showed a reduction in AtACBP6 expression in the pdlp8 T-DNA insertional mutant, suggesting that PDLP8 may possibly influence AtACBP6 accumulation in the sieve elements, probably in the plasmodesmata, where PDLP8 is confined and to where AtACBP6 has been immunodetected.
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Affiliation(s)
- Zi-Wei Ye
- School of Biological Sciences, The University of Hong Kong, Hong Kong, China
| | - Qin-Fang Chen
- School of Biological Sciences, The University of Hong Kong, Hong Kong, China
| | - Mee-Len Chye
- School of Biological Sciences, The University of Hong Kong, Hong Kong, China
- CONTACT Mee-Len Chye , School of Biological Sciences, The University of Hong Kong, 7S13, Kadoorie Building, HKU, Pokfulam, Hong Kong, China
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Striberny B, Melton AE, Schwacke R, Krause K, Fischer K, Goertzen LR, Rashotte AM. Cytokinin Response Factor 5 has transcriptional activity governed by its C-terminal domain. Plant Signal Behav 2017; 12:e1276684. [PMID: 28045578 PMCID: PMC5351726 DOI: 10.1080/15592324.2016.1276684] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/11/2016] [Revised: 12/16/2016] [Accepted: 12/21/2016] [Indexed: 05/26/2023]
Abstract
Cytokinin Response Factors (CRFs) are AP2/ERF transcription factors involved in cytokinin signal transduction. CRF proteins consist of a N-terminal dimerization domain (CRF domain), an AP2 DNA-binding domain, and a clade-specific C-terminal region of unknown function. Using a series of sequential deletions in yeast-2-hybrid assays, we provide evidence that the C-terminal region of Arabidopsis CRF5 can confer transactivation activity. Although comparative analyses identified evolutionarily conserved protein sequence within the C-terminal region, deletion experiments suggest that this transactivation domain has a partially redundant modular structure required for activation of target gene transcription.
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Affiliation(s)
- Bernd Striberny
- Department of Arctic and Marine Biology, UiT The Arctic University of Norway in Tromsø, Dramsvegen, Tromsø, Norway
- ArcticZymes AS, Sykehusveien, Tromsø, Norway
| | - Anthony E. Melton
- Department of Biological Sciences, Auburn University, Auburn, AL, USA
| | - Rainer Schwacke
- Department of Arctic and Marine Biology, UiT The Arctic University of Norway in Tromsø, Dramsvegen, Tromsø, Norway
| | - Kirsten Krause
- Department of Arctic and Marine Biology, UiT The Arctic University of Norway in Tromsø, Dramsvegen, Tromsø, Norway
| | - Karsten Fischer
- Department of Arctic and Marine Biology, UiT The Arctic University of Norway in Tromsø, Dramsvegen, Tromsø, Norway
| | | | - Aaron M. Rashotte
- Department of Biological Sciences, Auburn University, Auburn, AL, USA
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Drechsler F, Schwinges P, Schirawski J. SUPPRESSOR OF APICAL DOMINANCE1 of Sporisorium reilianum changes inflorescence branching at early stages in di- and monocot plants and induces fruit abortion in Arabidopsis thaliana. Plant Signal Behav 2016; 11:e1167300. [PMID: 27058118 PMCID: PMC4973792 DOI: 10.1080/15592324.2016.1167300] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2016] [Revised: 03/10/2016] [Accepted: 03/12/2016] [Indexed: 05/25/2023]
Abstract
sporisorium reilianum f. sp. zeae is a biotrophic smut fungus that infects maize (Zea mays). Among others, the fungus-plant interaction is governed by secreted fungal effector proteins. The effector SUPPRESSOR OF APICAL DOMINANCE1 (SAD1) changes the development of female inflorescences and induces outgrowth of subapical ears in S. reilianum-infected maize. When stably expressed in Arabidopsis thaliana as a GFP-SAD1 fusion protein, SAD1 induces earlier inflorescence branching and abortion of siliques. Absence of typical hormone-dependent phenotypes in other parts of the transgenic A. thaliana plants expressing GFP-SAD1 hint to a hormone-independent induction of bud outgrowth by SAD1. Silique abortion and bud outgrowth are also known to be controlled by carbon source concentration and by stress-induced molecules, making these factors interesting potential SAD1 targets.
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Affiliation(s)
- Frank Drechsler
- Microbial Genetics, Institute of Applied Microbiology, Aachen Biology and Biotechnology, RWTH Aachen University, Aachen, Germany
| | - Patrick Schwinges
- Microbial Genetics, Institute of Applied Microbiology, Aachen Biology and Biotechnology, RWTH Aachen University, Aachen, Germany
| | - Jan Schirawski
- Microbial Genetics, Institute of Applied Microbiology, Aachen Biology and Biotechnology, RWTH Aachen University, Aachen, Germany
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7
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Della Rovere F, Fattorini L, Ronzan M, Falasca G, Altamura MM. The quiescent center and the stem cell niche in the adventitious roots of Arabidopsis thaliana. Plant Signal Behav 2016; 11:e1176660. [PMID: 27089118 PMCID: PMC4973785 DOI: 10.1080/15592324.2016.1176660] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Adventitious rooting is essential for the survival of numerous species from vascular cryptogams to monocots, and is required for successful micropropagation. The tissues involved in AR initiation may differ in planta and in in vitro systems. For example, in Arabidopsis thaliana, ARs originate from the hypocotyl pericycle in planta and the stem endodermis in in vitro cultured thin cell layers. The formation of adventitious roots (ARs) depends on numerous factors, among which the hormones, auxin, in particular. In both primary and lateral roots, growth depends on a functional stem cell niche in the apex, maintained by an active quiescent center (QC), and involving the expression of genes controlled by auxin and cytokinin. This review summarizes current knowledge about auxin and cytokinin control on genes involved in the definition and maintenance of QC, and stem cell niche, in the apex of Arabidopsis ARs in planta and in longitudinal thin cell layers.
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Affiliation(s)
- Federica Della Rovere
- Department of Environmental Biology, Sapienza University of Rome, P.le Aldo Moro, Rome, Italy
| | - Laura Fattorini
- Department of Environmental Biology, Sapienza University of Rome, P.le Aldo Moro, Rome, Italy
| | - Marilena Ronzan
- Department of Environmental Biology, Sapienza University of Rome, P.le Aldo Moro, Rome, Italy
| | - Giuseppina Falasca
- Department of Environmental Biology, Sapienza University of Rome, P.le Aldo Moro, Rome, Italy
| | - Maria Maddalena Altamura
- Department of Environmental Biology, Sapienza University of Rome, P.le Aldo Moro, Rome, Italy
- Maria Maddalena Altamura
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8
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Ederveen A, Lai Y, van Driel MA, Gerats T, Peters JL. Modulating crossover positioning by introducing large structural changes in chromosomes. BMC Genomics 2015; 16:89. [PMID: 25879408 PMCID: PMC4359564 DOI: 10.1186/s12864-015-1276-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2014] [Accepted: 01/22/2015] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Crossing over assures the correct segregation of the homologous chromosomes to both poles of the dividing meiocyte. This exchange of DNA creates new allelic combinations thus increasing the genetic variation present in offspring. Crossovers are not uniformly distributed along chromosomes; rather there are preferred locations where they may take place. The positioning of crossovers is known to be influenced by both exogenous and endogenous factors as well as structural features inherent to the chromosome itself. We have introduced large structural changes into Arabidopsis chromosomes and report their effects on crossover positioning. RESULTS The introduction of large deletions and putative inversions silenced recombination over the length of the structural change. In the majority of cases analyzed, the total recombination frequency over the chromosomes was unchanged. The loss of crossovers at the sites of structural change was compensated for by increases in recombination frequencies elsewhere on the chromosomes, mostly in single intervals of one to three megabases in size. Interestingly, two independent cases of induced structural changes in the same chromosomal interval were found on both chromosomes 1 and 2. In both cases, compensatory increases in recombination frequencies were of similar strength and took place in the same chromosome region. In contrast, deletions in chromosome arms carrying the nucleolar organizing region did not change recombination frequencies in the remainder of those chromosomes. CONCLUSIONS When taken together, these observations show that changes in the physical structure of the chromosome can have large effects on the positioning of COs within that chromosome. Moreover, different reactions to induced structural changes are observed between and within chromosomes. However, the similarity in reaction observed when looking at chromosomes carrying similar changes suggests a direct causal relation between induced change and observed reaction.
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Affiliation(s)
- Antoine Ederveen
- Department of Molecular Plant Physiology, Radboud University Nijmegen, Institute for Water and Wetland Research (IWWR), Heyendaalseweg 135, 6525 AJ, Nijmegen, The Netherlands.
| | - Yuching Lai
- Netherlands Bioinformatics Centre, 260 NBIC, P.O. Box 9101, 6500 HB, Nijmegen, The Netherlands.
- The Delft Bioinformatics Lab, Department of Intelligent Systems, Delft University of Technology, Mekelweg 4, 2628 CD, Delft, The Netherlands.
| | - Marc A van Driel
- Netherlands Bioinformatics Centre, 260 NBIC, P.O. Box 9101, 6500 HB, Nijmegen, The Netherlands.
- Current affiliation: Philips Research, High Tech Campus 11, 5656 AE, Eindhoven, The Netherlands.
| | - Tom Gerats
- Department of Molecular Plant Physiology, Radboud University Nijmegen, Institute for Water and Wetland Research (IWWR), Heyendaalseweg 135, 6525 AJ, Nijmegen, The Netherlands.
| | - Janny L Peters
- Department of Molecular Plant Physiology, Radboud University Nijmegen, Institute for Water and Wetland Research (IWWR), Heyendaalseweg 135, 6525 AJ, Nijmegen, The Netherlands.
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Sassi M, Traas J. New insights in shoot apical meristem morphogenesis: Isotropy comes into play. Plant Signal Behav 2015; 10:e1000150. [PMID: 26337646 PMCID: PMC4883928 DOI: 10.1080/15592324.2014.1000150] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2014] [Accepted: 12/14/2014] [Indexed: 06/05/2023]
Abstract
The great complexity and plasticity of aerial plant shapes largely results from the activity of the shoot apical meristem (SAM), a group of undifferentiated cells which produces all the aboveground organs of the plant. Organogenesis at the SAM is regulated by the hormone auxin, which, through an integration of active transport, signalling and transcriptional regulation, determines the positional and temporal information dictating where, when, and how a new organ will be formed. At the cellular level, the information stemming from the regulatory molecular networks influences the growth of the cells within the tissue to give rise to the final organ shape. The growth of plant cells is mainly controlled by the cell wall, a rigid structure mainly made of polysaccharides, which surrounds the cells and links them together in an organismal continuum. Over the years, several lines of evidence have pointed at a role for the regulation of the elasticity of the cell wall, downstream of auxin action, in the formation of organs at the SAM. We have recently shown that auxin also induces a shift toward isotropic growth by modulating the organization of cortical microtubules in peripheral SAM cells, which promotes organ formation. Here, we discuss our results and identify new hypotheses to drive future research.
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Affiliation(s)
- Massimiliano Sassi
- Laboratoire de Reproduction et Développement des Plantes; INRA; CNRS; ENS; UCBL; Lyon, France
| | - Jan Traas
- Laboratoire de Reproduction et Développement des Plantes; INRA; CNRS; ENS; UCBL; Lyon, France
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10
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Vieira P, Engler JDA. The plant cell inhibitor KRP6 is involved in multinucleation and cytokinesis disruption in giant-feeding cells induced by root-knot nematodes. Plant Signal Behav 2015; 10:e1010924. [PMID: 25915833 PMCID: PMC4622652 DOI: 10.1080/15592324.2015.1010924] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 12/04/2014] [Revised: 01/14/2015] [Accepted: 01/15/2015] [Indexed: 06/04/2023]
Abstract
The plant cell cycle inhibitor gene KRP6 has been investigated in roots infected by plant-parasitic root-knot nematodes (Meloidogyne spp.). Unexpectedly, KRP6 overexpressing lines revealed a distinct role for this specific KRP as an activator of the mitotic cell cycle. This function was confirmed in Arabidopsis thaliana suspension cultures ectopically expressing KRP6. A blockage in the mitotic exit was observed in cell suspensions and in giant cells resulted in the appearance of multi-nucleated cells. KRP6 expression during nematode infection and the similarity in phenotypes among KRP6 overexpressing cell cultures and giant-cell morphology strongly suggest that KRP6 is involved in multinucleation and acytokinesis occurring in giant-cells. Once again nematodes have been shown to manipulate the plant cell cycle machinery in order to promote gall establishment.
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Affiliation(s)
- Paulo Vieira
- Lab. Nematologia/ICAAM-Instituto de Ciências Agrárias e Ambientais Mediterrânicas; Universidade de Évora; Núcleo da Mitra; Évora, Portugal
| | - Janice de Almeida Engler
- Institut National de la Recherche Agronomique; UMR 1355 ISA/Center National de la Recherche Scientifique; UMR 7254 ISA/ Université de Nice-Sophia Antipolis; UMR ISA; Sophia-Antipolis, France
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11
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Kaya H, Iwano M, Takeda S, Kanaoka MM, Kimura S, Abe M, Kuchitsu K. Apoplastic ROS production upon pollination by RbohH and RbohJ in Arabidopsis. Plant Signal Behav 2015; 10:e989050. [PMID: 25751652 PMCID: PMC4623480 DOI: 10.4161/15592324.2014.989050] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/10/2014] [Revised: 10/01/2014] [Accepted: 10/02/2014] [Indexed: 05/17/2023]
Abstract
Reactive oxygen species (ROS) accumulate at the tip of growing pollen tubes. In Arabidopsis, NADPH oxidases RbohH and RbohJ are localized at the plasma membrane of pollen tube tip and produce ROS in a Ca(2+)-dependent manner. The ROS produced by Rbohs and Ca(2+) presumably play a critical role in the positive feedback regulation that maintains the tip growth. Ultrastructural cytochemical analysis revealed ROS accumulation in the apoplast/cell wall of the pollen grains on the stigmatic papillae in the wild type, but not in the rbohH rbohJ double mutant, suggesting that apoplastic ROS derived from RbohH and RbohJ are involved in pollen tube elongation into the stigmatic papillae by affecting the cell wall metabolism.
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Affiliation(s)
- Hidetaka Kaya
- Department of Applied Biological Science; Tokyo University of Science; Noda, Japan
- Correspondence to: Hidetaka Kaya; ; Kazuyuki Kuchitsu;
| | - Megumi Iwano
- Graduate School of Biological Sciences; Nara Institute of Science and Technology; Ikoma, Japan
| | - Seiji Takeda
- Graduate School of Life and Environmental Sciences; Kyoto Prefectural University; Kyoto, Japan
- Biotechnology Research Department; Kyoto Prefectural Agriculture Forestry and Fisheries Technology Center; Kyoto, Japan
| | - Masahiro M Kanaoka
- Division of Biological Science; Graduate School of Science
- Institute of Transformative Bio-Molecules (ITbM); Nagoya University; Nagoya, Japan
| | - Sachie Kimura
- Department of Applied Biological Science; Tokyo University of Science; Noda, Japan
| | - Mitsutomo Abe
- Department of Biological Science; Graduate School of Science; The University of Tokyo; Tokyo, Japan
| | - Kazuyuki Kuchitsu
- Department of Applied Biological Science; Tokyo University of Science; Noda, Japan
- Correspondence to: Hidetaka Kaya; ; Kazuyuki Kuchitsu;
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12
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Schellingen K, Van Der Straeten D, Vandenbussche F, Prinsen E, Remans T, Vangronsveld J, Cuypers A. Cadmium-induced ethylene production and responses in Arabidopsis thaliana rely on ACS2 and ACS6 gene expression. BMC Plant Biol 2014; 14:214. [PMID: 25082369 PMCID: PMC4236733 DOI: 10.1186/s12870-014-0214-6] [Citation(s) in RCA: 86] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/06/2014] [Accepted: 07/24/2014] [Indexed: 05/19/2023]
Abstract
BACKGROUND Anthropogenic activities cause metal pollution worldwide. Plants can absorb and accumulate these metals through their root system, inducing stress as a result of excess metal concentrations inside the plant. Ethylene is a regulator of multiple plant processes, and is affected by many biotic and abiotic stresses. Increased ethylene levels have been observed after exposure to excess metals but it remains unclear how the increased ethylene levels are achieved at the molecular level. In this study, the effects of cadmium (Cd) exposure on the production of ethylene and its precursor 1-aminocyclopropane-1-carboxylic acid (ACC), and on the expression of the ACC Synthase (ACS) and ACC Oxidase (ACO) multigene families were investigated in Arabidopsis thaliana. RESULTS Increased ethylene release after Cd exposure was directly measurable in a system using rockwool-cultivated plants; enhanced levels of the ethylene precursor ACC together with higher mRNA levels of ethylene responsive genes: ACO2, ETR2 and ERF1 also indicated increased ethylene production in hydroponic culture. Regarding underlying mechanisms, it was found that the transcript levels of ACO2 and ACO4, the most abundantly expressed members of the ACO multigene family, were increased upon Cd exposure. ACC synthesis is the rate-limiting step in ethylene biosynthesis, and transcript levels of both ACS2 and ACS6 showed the highest increase and became the most abundant isoforms after Cd exposure, suggesting their importance in the Cd-induced increase of ethylene production. CONCLUSIONS Cadmium induced the biosynthesis of ACC and ethylene in Arabidopsis thaliana plants mainly via the increased expression of ACS2 and ACS6. This was confirmed in the acs2-1acs6-1 double knockout mutants, which showed a decreased ethylene production, positively affecting leaf biomass and resulting in a delayed induction of ethylene responsive gene expressions without significant differences in Cd contents between wild-type and mutant plants.
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Affiliation(s)
- Kerim Schellingen
- Centre for Environmental Sciences, Hasselt University, Agoralaan Building D, Diepenbeek, 3590, Belgium
| | - Dominique Van Der Straeten
- Laboratory for Functional Plant Biology, Ghent University, Karel Lodewijk Ledeganckstraat 35, Ghent, 9000, Belgium
| | - Filip Vandenbussche
- Laboratory for Functional Plant Biology, Ghent University, Karel Lodewijk Ledeganckstraat 35, Ghent, 9000, Belgium
| | - Els Prinsen
- Laboratory of Plant Growth and Development, University of Antwerp, Groenenborgerlaan 171, Antwerp, 2020, Belgium
| | - Tony Remans
- Centre for Environmental Sciences, Hasselt University, Agoralaan Building D, Diepenbeek, 3590, Belgium
| | - Jaco Vangronsveld
- Centre for Environmental Sciences, Hasselt University, Agoralaan Building D, Diepenbeek, 3590, Belgium
| | - Ann Cuypers
- Centre for Environmental Sciences, Hasselt University, Agoralaan Building D, Diepenbeek, 3590, Belgium
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Stoll B, Zendler D, Binder S. RNA processing factor 7 and polynucleotide phosphorylase are necessary for processing and stability of nad2 mRNA in Arabidopsis mitochondria. RNA Biol 2014; 11:968-76. [PMID: 25181358 DOI: 10.4161/rna.29781] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Post-transcriptional maturation of plant mitochondrial transcripts requires several steps. Among these, the generation of mature 5' ends is still one of the most enigmatic processes. Toward a characterization of proteins involved in 5' processing of mitochondrial transcripts in Arabidopsis (Arabidopsis thaliana), we now analyzed 5' maturation of nad2 transcripts. Based on natural genetic variation affecting 5' ends of nad2 transcripts in ecotype Can-0 and complementation studies we now identified RNA processing factor 7, which takes part in the generation of the 5' terminus of the mature nad2 mRNA. RPF7 is a relatively short regular P-class pentatricopeptide repeat protein comprising seven canonical P repeats and a single short S repeat. The corresponding allele in Can-0 encodes a truncated version of this protein lacking two C-terminal repeats, which are essential for the function of RPF7. Furthermore we established transgenic plants expressing artifical microRNAs targeting the mitochondrial polynucleotide phosphorylase (PNPase), which results in substantial reduction of the PNPase mRNA levels and strong knockdown of this gene. Detailed quantitative studies of 5' and 3' extended nad2 precursor RNAs in these knockdown plants as well as in the rpf7-1 knockout mutant suggest that 5' processing contributes to the stability of mitochondrial transcripts in plants.
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Affiliation(s)
- Birgit Stoll
- Institut Molekulare Botanik, Universität Ulm, Germany
| | | | - Stefan Binder
- Institut Molekulare Botanik, Universität Ulm, Germany
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14
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Boccaccini A, Santopolo S, Capauto D, Lorrai R, Minutello E, Belcram K, Palauqui JC, Costantino P, Vittorioso P. Independent and interactive effects of DOF affecting germination 1 (DAG1) and the Della proteins GA insensitive (GAI) and Repressor of ga1-3 (RGA) in embryo development and seed germination. BMC Plant Biol 2014; 14:200. [PMID: 25064446 PMCID: PMC4222566 DOI: 10.1186/s12870-014-0200-z] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/24/2014] [Accepted: 07/16/2014] [Indexed: 05/22/2023]
Abstract
BACKGROUND The transcription factor DOF AFFECTING GERMINATION1 (DAG1) is a repressor of seed germination acting downstream of the master repressor PHYTOCROME INTERACTING FACTOR3-LIKE 5 (PIL5). Among others, PIL5 induces the expression of the genes encoding the two DELLA proteins GA INSENSITIVE 1 (GAI) and REPRESSOR OF ga1-3 (RGA). RESULTS Based on the properties of gai-t6 and rga28 mutant seeds, we show here that the absence of RGA severely increases dormancy, while lack of GAI only partially compensates RGA inactivation. In addition, the germination properties of the dag1rga28 double mutant are different from those of the dag1 and rga28 single mutants, suggesting that RGA and DAG1 act in independent branches of the PIL5-controlled germination pathway. Surprisingly, the dag1gai-t6 double mutant proved embryo-lethal, suggesting an unexpected involvement of (a possible complex between) DAG1 and GAI in embryo development. CONCLUSIONS Rather than overlapping functions as previously suggested, we show that RGA and GAI play distinct roles in seed germination, and that GAI interacts with DAG1 in embryo development.
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Affiliation(s)
- Alessandra Boccaccini
- Istituto Pasteur Fondazione Cenci Bolognetti, Dipartimento di Biologia e Biotecnologie “C. Darwin”, Sapienza Università di Roma, Piazzale Aldo Moro 5, Rome, 00185, Italy
| | - Silvia Santopolo
- Istituto Pasteur Fondazione Cenci Bolognetti, Dipartimento di Biologia e Biotecnologie “C. Darwin”, Sapienza Università di Roma, Piazzale Aldo Moro 5, Rome, 00185, Italy
| | - Davide Capauto
- Istituto Pasteur Fondazione Cenci Bolognetti, Dipartimento di Biologia e Biotecnologie “C. Darwin”, Sapienza Università di Roma, Piazzale Aldo Moro 5, Rome, 00185, Italy
| | - Riccardo Lorrai
- Istituto Pasteur Fondazione Cenci Bolognetti, Dipartimento di Biologia e Biotecnologie “C. Darwin”, Sapienza Università di Roma, Piazzale Aldo Moro 5, Rome, 00185, Italy
| | - Emanuele Minutello
- Istituto Pasteur Fondazione Cenci Bolognetti, Dipartimento di Biologia e Biotecnologie “C. Darwin”, Sapienza Università di Roma, Piazzale Aldo Moro 5, Rome, 00185, Italy
| | - Katia Belcram
- Institut Jean-Pierre Bourgin, UMR1318 INRA-AgroParisTech, Bâtiment 2, INRA, Centre de Versailles-Grignon, Route de St-Cyr (RD10), Versailles Cedex, 78026, France
| | - Jean-Cristophe Palauqui
- Institut Jean-Pierre Bourgin, UMR1318 INRA-AgroParisTech, Bâtiment 2, INRA, Centre de Versailles-Grignon, Route de St-Cyr (RD10), Versailles Cedex, 78026, France
| | - Paolo Costantino
- Istituto Pasteur Fondazione Cenci Bolognetti, Dipartimento di Biologia e Biotecnologie “C. Darwin”, Sapienza Università di Roma, Piazzale Aldo Moro 5, Rome, 00185, Italy
| | - Paola Vittorioso
- Istituto Pasteur Fondazione Cenci Bolognetti, Dipartimento di Biologia e Biotecnologie “C. Darwin”, Sapienza Università di Roma, Piazzale Aldo Moro 5, Rome, 00185, Italy
- Dipartimento di Biologia e Biotecnologie “C. Darwin”, Sapienza Università di Roma, Piazzale Aldo Moro 5, Rome, 00185, Italy
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15
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Abstract
Arabidopsis thaliana is the first model plant, the genome of which has been sequenced. In general, intensive studies on this model plant over the past nearly 30 years have led to many new revolutionary understandings in every single aspect of plant biology. Here, we review the current understanding of anthocyanin biosynthesis in this model plant. Although the investigation of anthocyanin structures in this model plant was not performed until 2002, numerous studies over the past three decades have been conducted to understand the biosynthesis of anthocyanins. To date, it appears that all pathway genes of anthocyanins have been molecularly, genetically and biochemically characterized in this plant. These fundamental accomplishments have made Arabidopsis an ideal model to understand the regulatory mechanisms of anthocyanin pathway. Several studies have revealed that the biosynthesis of anthocyanins is controlled by WD40-bHLH-MYB (WBM) transcription factor complexes under lighting conditions. However, how different regulatory complexes coordinately and specifically regulate the pathway genes of anthocyanins remains unclear. In this review, we discuss current progresses and findings including structural diversity, regulatory properties and metabolic engineering of anthocyanins in Arabidopsis thaliana.
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Affiliation(s)
| | - De-Yu Xie
- Department of Plant and Microbial Biology, North Carolina State University, Raleigh, NC 27695, USA.
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16
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Kourmpetli S, Lee K, Hemsley R, Rossignol P, Papageorgiou T, Drea S. Bidirectional promoters in seed development and related hormone/stress responses. BMC Plant Biol 2013; 13:187. [PMID: 24261334 PMCID: PMC4222868 DOI: 10.1186/1471-2229-13-187] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2013] [Accepted: 11/15/2013] [Indexed: 05/03/2023]
Abstract
BACKGROUND Bidirectional promoters are common in genomes but under-studied experimentally, particularly in plants. We describe a targeted identification and selection of a subset of putative bidirectional promoters to identify genes involved in seed development and to investigate possible coordinated responses of gene pairs to conditions important in seed maturation such as desiccation and ABA-regulation. RESULTS We combined a search for 100-600 bp intergenic regions in the Arabidopsis genome with a cis-element based selection for those containing multiple copies of the G-box motif, CACGTG. One of the putative bidirectional promoters identified also contained a CE3 coupling element 5 bp downstream of one G-box and is identical to that characterized previously in the HVA1 promoter of barley. CE3 elements are significantly under-represented and under-studied in Arabidopsis. We further characterized the pair of genes associated with this promoter and uncovered roles for two small, previously uncharacterized, plant-specific proteins in Arabidopsis seed development and stress responses. CONCLUSIONS Using bioinformatics we identified putative bidirectional promoters involved in seed development and analysed expression patterns for a pair of plant-specific genes in various tissues and in response to hormones/stress. We also present preliminary functional analysis of these genes that is suggestive of roles in seed development.
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Affiliation(s)
- Sofia Kourmpetli
- Department of Biology, University of Leicester, University Road, Leicester LE1 7RH, UK
| | - Kate Lee
- Bioinformatics and Biostatistics Analysis Support Hub (BBASH), College of Medicine, Biological Sciences and Psychology, University of Leicester, Leicester, UK
| | - Rachel Hemsley
- Current address UCL Business PLC, The Network Building, 97 Tottenham Court Road, London W1T 4TP, UK
| | - Pascale Rossignol
- Current address Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT 06520, USA
| | - Thaleia Papageorgiou
- Department of Biology, University of Leicester, University Road, Leicester LE1 7RH, UK
| | - Sinéad Drea
- Department of Biology, University of Leicester, University Road, Leicester LE1 7RH, UK
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17
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Jacques E, Verbelen JP, Vissenberg K. Mechanical stress in Arabidopsis leaves orients microtubules in a 'continuous' supracellular pattern. BMC Plant Biol 2013; 13:163. [PMID: 24138025 PMCID: PMC3853881 DOI: 10.1186/1471-2229-13-163] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2012] [Accepted: 10/09/2013] [Indexed: 05/02/2023]
Abstract
BACKGROUND Cortical microtubules form a dynamic network and continuously undergo shrinking (catastrophe), pausing and rebuilding (rescue). The advantage of such a dynamic system is that it may mediate appropriate responses in a short time span. Microtubules are known to play a pivotal role in determining the orientation of the cellulose microfibril deposition in the plant cell wall. The latter is a solid exoskeleton surrounding the protoplast. It forms the physical framework that interconnects most cells and has to bear the tensile stresses within the tissue. Here we describe the effect of externally applied pressure on microtubule organization in growing Arabidopsis leaves. RESULTS Confocal microscopy examination of transgenic plants bearing GFP-tagged TUA6 proteins led to the observation that application of an additional mechanical pressure on growing Arabidopsis leaves triggers an excessive bundling of microtubules within the individual cell. Besides, the microtubules seem to align in neighboring cells, creating a 'continuous' supracellular pattern. This effect occurs within 3 hours after applied external force and is age-dependent, whereby only cells of leaves up to 19 days after sowing (DAS) are susceptible to the applied pressure. CONCLUSIONS Upon externally applied pressure on developing Arabidopsis leaves, microtubules bundle and rearrange to form seemingly continuous supracellular patterns. As microtubules guide the cellulose synthase complexes, this observed reorganisation pattern probably affects the cellulose deposition, contributing to the reinforcement of the cell wall in a particular position to cope with the extra-applied pressure. The age-effect is reasonable, since younger cells, which are actively shaping their cell walls, are more vulnerable to altered mechanical stresses while in leaves older than 19 DAS, the walls are more robust and therefore can sustain the applied forces.
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Affiliation(s)
- Eveline Jacques
- Department Biology, Plant Growth and Development, University of Antwerp, Groenenborgerlaan 171, 2020 Antwerpen, Belgium
| | - Jean-Pierre Verbelen
- Department Biology, Plant Growth and Development, University of Antwerp, Groenenborgerlaan 171, 2020 Antwerpen, Belgium
| | - Kris Vissenberg
- Department Biology, Plant Growth and Development, University of Antwerp, Groenenborgerlaan 171, 2020 Antwerpen, Belgium
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18
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Abstract
The life cycle of plants is strictly regulated by light, which directly influences the initiation of developmental programs such as photomorphogenesis of seedlings and induction of flowering. When environmental conditions are unsuitable, both processes are actively repressed by the action of COP1/SPA protein complexes which participate in ubiquitylation and subsequent degradation of transcription factors. We have shown recently that MIDGET (MID), a regulator of the TOPOISOMERASE VI complex, physically interacts with COP1 and is required for its function as suppressor of photomorphogenesis. Here we show that in Arabidopsis thaliana, the MID protein similarly plays a role in COP1/SPA1-controlled repression of flowering under short-day conditions.
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19
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Tricker PJ, Rodríguez López CM, Hadley P, Wagstaff C, Wilkinson MJ. Pre-conditioning the epigenetic response to high vapor pressure deficit increases the drought tolerance of Arabidopsis thaliana. Plant Signal Behav 2013; 8:25974. [PMID: 24270688 PMCID: PMC4091208 DOI: 10.4161/psb.25974] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/12/2013] [Revised: 07/30/2013] [Accepted: 07/31/2013] [Indexed: 05/22/2023]
Abstract
Epigenetic modification of the genome via cytosine methylation is a dynamic process that responds to changes in the growing environment. This modification can also be heritable. The combination of both properties means that there is the potential for the life experiences of the parental generation to modify the methylation profiles of their offspring and so potentially to “pre-condition” them to better accommodate abiotic conditions encountered by their parents. We recently identified high vapor pressure deficit (vpd)-induced DNA methylation at 2 gene loci in the stomatal development pathway and an associated reduction in leaf stomatal frequency.1 Here, we test whether this epigenetic modification pre-conditioned parents and their offspring to the more severe water stress of periodic drought. We found that 3 generations of high vpd-grown plants were better able to withstand periodic drought stress over 2 generations. This resistance was not directly associated with de novo methylation of the target stomata genes, but was associated with the cmt3 mutant’s inability to maintain asymmetric sequence context methylation. If our finding applies widely, it could have significant implications for evolutionary biology and breeding for stressful environments.
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Affiliation(s)
- Penny J Tricker
- School of Biological Sciences; University of Reading; Whiteknights; Reading, UK
| | - Carlos M Rodríguez López
- Institute of Biological; Environmental and Rural Sciences; Edward Llywd Building; University of Aberystwyth; Aberystwyth, Ceredigion, UK
| | - P Hadley
- School of Biological Sciences; University of Reading; Whiteknights; Reading, UK
| | - C Wagstaff
- Department of Food and Nutritional Sciences; University of Reading; Whiteknights; Reading, UK
| | - Mike J Wilkinson
- Institute of Biological; Environmental and Rural Sciences; Edward Llywd Building; University of Aberystwyth; Aberystwyth, Ceredigion, UK
- Correspondence to: Mike J Wilkinson,
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20
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Yamashino T, Nomoto Y, Lorrain S, Miyachi M, Ito S, Nakamichi N, Fankhauser C, Mizuno T. Verification at the protein level of the PIF4-mediated external coincidence model for the temperature-adaptive photoperiodic control of plant growth in Arabidopsis thaliana. Plant Signal Behav 2013; 8:e23390. [PMID: 23299336 PMCID: PMC3676505 DOI: 10.4161/psb.23390] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Plant circadian clock controls a wide variety of physiological and developmental events, which include the short-days (SDs)-specific promotion of the elongation of hypocotyls during de-etiolation and also the elongation of petioles during vegetative growth. In A. thaliana, the PIF4 gene encoding a phytochrome-interacting basic helix-loop-helix (bHLH) transcription factor plays crucial roles in this photoperiodic control of plant growth. According to the proposed external coincidence model, the PIF4 gene is transcribed precociously at the end of night specifically in SDs, under which conditions the protein product is stably accumulated, while PIF4 is expressed exclusively during the daytime in long days (LDs), under which conditions the protein product is degraded by the light-activated phyB and also the residual proteins are inactivated by the DELLA family of proteins. A number of previous reports provided solid evidence to support this coincidence model mainly at the transcriptional level of the PIF 4 and PIF4-traget genes. Nevertheless, the diurnal oscillation profiles of PIF4 proteins, which were postulated to be dependent on photoperiod and ambient temperature, have not yet been demonstrated. Here we present such crucial evidence on PIF4 protein level to further support the external coincidence model underlying the temperature-adaptive photoperiodic control of plant growth in A. thaliana.
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Affiliation(s)
- Takafumi Yamashino
- Laboratory of Molecular and Functional Genomics; School of Agriculture; Nagoya University; Nagoya, Japan
- Correspondence to: Takafumi Yamashino,
| | - Yuji Nomoto
- Laboratory of Molecular and Functional Genomics; School of Agriculture; Nagoya University; Nagoya, Japan
| | - Séverine Lorrain
- Center for Integrative Genomics; Faculty of Biology and Medicine; University of Lausanne; Lausanne, Switzerland
| | - Miki Miyachi
- Laboratory of Molecular and Functional Genomics; School of Agriculture; Nagoya University; Nagoya, Japan
| | - Shogo Ito
- Laboratory of Molecular and Functional Genomics; School of Agriculture; Nagoya University; Nagoya, Japan
| | - Norihito Nakamichi
- Laboratory of Molecular and Functional Genomics; School of Agriculture; Nagoya University; Nagoya, Japan
| | - Christian Fankhauser
- Center for Integrative Genomics; Faculty of Biology and Medicine; University of Lausanne; Lausanne, Switzerland
| | - Takeshi Mizuno
- Laboratory of Molecular and Functional Genomics; School of Agriculture; Nagoya University; Nagoya, Japan
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21
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Streb S, Eicke S, Zeeman SC. The simultaneous abolition of three starch hydrolases blocks transient starch breakdown in Arabidopsis. J Biol Chem 2012; 287:41745-56. [PMID: 23019330 PMCID: PMC3516724 DOI: 10.1074/jbc.m112.395244] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2012] [Revised: 09/25/2012] [Indexed: 11/11/2022] Open
Abstract
In this study, we investigated which enzymes are involved in debranching amylopectin during transient starch degradation. Previous studies identified two debranching enzymes, isoamylase 3 (ISA3) and limit dextrinase (LDA), involved in this process. However, plants lacking both enzymes still degrade substantial amounts of starch. Thus, other enzymes/mechanisms must contribute to starch breakdown. We show that the chloroplastic α-amylase 3 (AMY3) also participates in starch degradation and provide evidence that all three enzymes can act directly at the starch granule surface. The isa3 mutant has a starch excess phenotype, reflecting impaired starch breakdown. In contrast, removal of AMY3, LDA, or both enzymes together has no impact on starch degradation. However, removal of AMY3 or LDA in addition to ISA3 enhances the starch excess phenotype. In plants lacking all three enzymes, starch breakdown is effectively blocked, and starch accumulates to the highest levels observed so far. This provides indirect evidence that the heteromultimeric debranching enzyme ISA1-ISA2 is not involved in starch breakdown. However, we illustrate that ISA1-ISA2 can hydrolyze small soluble branched glucans that accumulate when ISA3 and LDA are missing, albeit at a slow rate. Starch accumulation in the mutants correlates inversely with plant growth.
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Affiliation(s)
- Sebastian Streb
- Institute for Agricultural Sciences, ETH Zurich, Universitätsstrasse 2, 8092 Zurich, Switzerland.
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22
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Schreiber KJ, Austin RS, Gong Y, Zhang J, Fung P, Wang PW, Guttman DS, Desveaux D. Forward chemical genetic screens in Arabidopsis identify genes that influence sensitivity to the phytotoxic compound sulfamethoxazole. BMC Plant Biol 2012; 12:226. [PMID: 23176361 PMCID: PMC3541222 DOI: 10.1186/1471-2229-12-226] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/23/2012] [Accepted: 11/22/2012] [Indexed: 05/20/2023]
Abstract
BACKGROUND The sulfanilamide family comprises a clinically important group of antimicrobial compounds which also display bioactivity in plants. While there is evidence that sulfanilamides inhibit folate biosynthesis in both bacteria and plants, the complete network of plant responses to these compounds remains to be characterized. As such, we initiated two forward genetic screens in Arabidopsis in order to identify mutants that exhibit altered sensitivity to sulfanilamide compounds. These screens were based on the growth phenotype of seedlings germinated in the presence of the compound sulfamethoxazole (Smex). RESULTS We identified a mutant with reduced sensitivity to Smex, and subsequent mapping indicated that a gene encoding 5-oxoprolinase was responsible for this phenotype. A mutation causing enhanced sensitivity to Smex was mapped to a gene lacking any functional annotation. CONCLUSIONS The genes identified through our forward genetic screens represent novel mediators of Arabidopsis responses to sulfanilamides and suggest that these responses extend beyond the perturbation of folate biosynthesis.
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Affiliation(s)
- Karl J Schreiber
- Current address: Department of Plant & Microbial Biology, University of California, Berkeley, CA, 94720-3102, USA
| | - Ryan S Austin
- Current address: Southern Crop Protection and Food Research Centre, Agriculture & Agri-Food Canada, London, ON, N5V 4T3, Canada
| | - Yunchen Gong
- Centre for the Analysis of Genome Evolution & Function, University of Toronto, Toronto, ON, M5S 3B2, Canada
| | - Jianfeng Zhang
- Centre for the Analysis of Genome Evolution & Function, University of Toronto, Toronto, ON, M5S 3B2, Canada
| | - Pauline Fung
- Centre for the Analysis of Genome Evolution & Function, University of Toronto, Toronto, ON, M5S 3B2, Canada
| | - Pauline W Wang
- Centre for the Analysis of Genome Evolution & Function, University of Toronto, Toronto, ON, M5S 3B2, Canada
| | - David S Guttman
- Department of Cell & Systems Biology, University of Toronto, Toronto, ON, M5S 3B2, Canada
- Centre for the Analysis of Genome Evolution & Function, University of Toronto, Toronto, ON, M5S 3B2, Canada
| | - Darrell Desveaux
- Department of Cell & Systems Biology, University of Toronto, Toronto, ON, M5S 3B2, Canada
- Centre for the Analysis of Genome Evolution & Function, University of Toronto, Toronto, ON, M5S 3B2, Canada
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23
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Farrow SC, Emery RJN. Concurrent profiling of indole-3-acetic acid, abscisic acid, and cytokinins and structurally related purines by high-performance-liquid-chromatography tandem electrospray mass spectrometry. Plant Methods 2012; 8:42. [PMID: 23061971 PMCID: PMC3583190 DOI: 10.1186/1746-4811-8-42] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2012] [Accepted: 10/08/2012] [Indexed: 05/17/2023]
Abstract
UNLABELLED BACKGROUND Cytokinins (CKs) are a group of plant growth regulators that are involved in several plant developmental processes. Despite the breadth of knowledge surrounding CKs and their diverse functions, much remains to be discovered about the full potential of CKs, including their relationship with the purine salvage pathway, and other phytohormones. The most widely used approach to query unknown facets of CK biology utilized functional genomics coupled with CK metabolite assays and screening of CK associated phenotypes. There are numerous different types of assays for determining CK quantity, however, none of these methods screen for the compendium of metabolites that are necessary for elucidating all roles, including purine salvage pathway enzymes in CK metabolism, and CK cross-talk with other phytohormones. Furthermore, all published analytical methods have drawbacks ranging from the required use of radiolabelled compounds, or hazardous derivatization reagents, poor sensitivity, lack of resolution between CK isomers and lengthy run times. RESULTS In this paper, a method is described for the concurrent extraction, purification and analysis of several CKs (freebases, ribosides, glucosides, nucleotides), purines (adenosine monophosphate, inosine, adenosine, and adenine), indole-3-acetic acid, and abscisic acid from hundred-milligram (mg) quantities of Arabidopsis thaliana leaf tissue. This method utilizes conventional Bieleski solvents extraction, solid phase purification, and is unique because of its diverse range of detectable analytes, and implementation of a conventional HPLC system with a fused core column that enables good sensitivity without the requirement of a UHPLC system. Using this method we were able to resolve CKs about twice as fast as our previous method. Similarly, analysis of adenosine, indole-3-acetic acid, and abscisic acid, was comparatively rapid. A further enhancement of the method was the utilization of a QTRAP 5500 mass analyzer, which improved upon several aspects of our previous analytical method carried out on a Quattro mass analyzer. Notable improvements included much superior sensitivity, and number of analytes detectable within a single run. Limits of detection ranged from 2 pM for (9G)Z to almost 750 pM for indole-3-acetic acid. CONCLUSIONS This method is well suited for functional genomics platforms tailored to understanding CK metabolism, CK interrelationships with purine recycling and associated hormonal cross-talk.
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Affiliation(s)
- Scott C Farrow
- Biology Department, Trent University, Peterborough, ON, K9J 7B8, Canada
- Present Address: Department of Biological Sciences, University of Calgary, 2500 University Drive N.W., University of Calgary, Calgary, AB, T2N 1N4, Canada
| | - RJ Neil Emery
- Biology Department, Trent University, Peterborough, ON, K9J 7B8, Canada
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24
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Omidbakhshfard MA, Omranian N, Ahmadi FS, Nikoloski Z, Mueller-Roeber B. Effect of salt stress on genes encoding translation-associated proteins in Arabidopsis thaliana. Plant Signal Behav 2012; 7:1095-102. [PMID: 22899071 PMCID: PMC3489636 DOI: 10.4161/psb.21218] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Salinity negatively affects plant growth and disturbs chloroplast integrity. Here, we aimed at identifying salt-responsive translation-related genes in Arabidopsis thaliana with an emphasis on those encoding plastid-located proteins. We used quantitative real-time PCR to test the expression of 170 genes after short-term salt stress (up to 24 h) and identified several genes affected by the stress including: PRPL11, encoding plastid ribosomal protein L11, ATAB2, encoding a chloroplast-located RNA-binding protein presumably functioning as an activator of translation, and PDF1B, encoding a peptide deformylase involved in N-formyl group removal from nascent proteins synthesized in chloroplasts. These genes were previously shown to have important functions in chloroplast biology and may therefore represent new targets for biotechnological optimization of salinity tolerance.
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Affiliation(s)
- Mohammad Amin Omidbakhshfard
- University of Potsdam; Institute of Biochemistry and Biology; Potsdam, Germany
- Max-Planck Institute of Molecular Plant Physiology; Potsdam-Golm, Germany
- Ferdowsi University of Mashhad; Department of Crop Biotechnology and Breeding; Mashhad, Iran
| | - Nooshin Omranian
- University of Potsdam; Institute of Biochemistry and Biology; Potsdam, Germany
- Max-Planck Institute of Molecular Plant Physiology; Potsdam-Golm, Germany
| | | | - Zoran Nikoloski
- Max-Planck Institute of Molecular Plant Physiology; Potsdam-Golm, Germany
| | - Bernd Mueller-Roeber
- University of Potsdam; Institute of Biochemistry and Biology; Potsdam, Germany
- Max-Planck Institute of Molecular Plant Physiology; Potsdam-Golm, Germany
- Correspondence to: Bernd Mueller-Roeber,
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25
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Abstract
Gamete formation is an important step in the life cycle of sexually reproducing organisms. In flowering plants, haploid spores are formed after the meiotic division of spore mother cells. These spores develop into male and female gametophytes containing gametes after undergoing mitotic divisions. In the female, the megaspore mother cell undergoes meiosis forming four megaspores, of which one is functional and three degenerate. The megaspore then undergoes three mitotic cycles thus generating an embryo sac with eight nuclei. The embryo sac undergoes cellularization to form the mature seven-celled female gametophyte. Entry into and progression through meiosis is essential for megasporogenesis and subsequent megagametogenesis, but control of this process is not well understood. FOUR LIPS (FLP) and its paralogue MYB88, encoding R2R3 MYB transcription factors, have been extensively studied for their role in limiting the terminal division in stomatal development by direct regulation of the expression of cell cycle genes. Here it is demonstrated that FLP and MYB88 also regulate female reproduction. Both FLP and MYB88 are expressed during ovule development and their loss significantly increases the number of ovules produced by the placenta. Despite the presence of excess ovules, single and double mutants exhibit reduced seed set due to reduced female fertility. The sterility results at least in part from defective meiotic entry and progression. Therefore, FLP and MYB88 are important regulators of entry into megasporogenesis, and probably act via the regulation of cell cycle genes.
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Affiliation(s)
- Srilakshmi Makkena
- Plant Cellular and Molecular Biology Graduate Program, The Ohio State University, Columbus, OH 43210, USA
- Department of Molecular Genetics, The Ohio State University,Columbus, OH 43210, USA
| | - Eunkyoung Lee
- Department of Botany, The University of British ColumbiaVancouver, BC, Canada V6T 1Z4
| | - Fred D. Sack
- Department of Botany, The University of British ColumbiaVancouver, BC, Canada V6T 1Z4
| | - Rebecca S. Lamb
- Department of Molecular Genetics, The Ohio State University,Columbus, OH 43210, USA
- To whom correspondence should be addressed. E-mail:
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Lee YP, Babakov A, de Boer B, Zuther E, Hincha DK. Comparison of freezing tolerance, compatible solutes and polyamines in geographically diverse collections of Thellungiella sp. and Arabidopsis thaliana accessions. BMC Plant Biol 2012; 12:131. [PMID: 22863402 PMCID: PMC3464606 DOI: 10.1186/1471-2229-12-131] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/24/2012] [Accepted: 07/13/2012] [Indexed: 05/05/2023]
Abstract
BACKGROUND Thellungiella has been proposed as an extremophile alternative to Arabidopsis to investigate environmental stress tolerance. However, Arabidopsis accessions show large natural variation in their freezing tolerance and here the tolerance ranges of collections of accessions in the two species were compared. RESULTS Leaf freezing tolerance of 16 Thellungiella accessions was assessed with an electrolyte leakage assay before and after 14 days of cold acclimation at 4°C. Soluble sugars (glucose, fructose, sucrose, raffinose) and free polyamines (putrescine, spermidine, spermine) were quantified by HPLC, proline photometrically. The ranges in nonacclimated freezing tolerance completely overlapped between Arabidopsis and Thellungiella. After cold acclimation, some Thellungiella accessions were more freezing tolerant than any Arabidopsis accessions. Acclimated freezing tolerance was correlated with sucrose levels in both species, but raffinose accumulation was lower in Thellungiella and only correlated with freezing tolerance in Arabidopsis. The reverse was true for leaf proline contents. Polyamine levels were generally similar between the species. Only spermine content was higher in nonacclimated Thellungiella plants, but decreased during acclimation and was negatively correlated with freezing tolerance. CONCLUSION Thellungiella is not an extremophile with regard to freezing tolerance, but some accessions significantly expand the range present in Arabidopsis. The metabolite data indicate different metabolic adaptation strategies between the species.
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Affiliation(s)
- Yang Ping Lee
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, Am Mühlenberg 1, Potsdam, D-14476, Germany
| | - Alexei Babakov
- All-Russia Research Institute of Agricultural Biotechnology RAAS, Timiryazevskaya St. 42, Moscow, 127550, Russia
| | - Bert de Boer
- Department of Structural Biology, Vrije Universiteit Amsterdam, De Boelelaan 1085-1087, Amsterdam, 1081 HV, The Netherlands
| | - Ellen Zuther
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, Am Mühlenberg 1, Potsdam, D-14476, Germany
| | - Dirk K Hincha
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, Am Mühlenberg 1, Potsdam, D-14476, Germany
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Shikata H, Nakashima M, Matsuoka K, Matsushita T. Deletion of the RS domain of RRC1 impairs phytochrome B signaling in Arabidopsis. Plant Signal Behav 2012; 7:933-936. [PMID: 22751357 PMCID: PMC3474688 DOI: 10.4161/psb.20854] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Phytochrome B (phyB), a major photoreceptor in plants, interacts with transcription factors to regulate gene expression and induce various light responses. Recently, we identified an SR-like splicing factor, RRC1 (reduced red-light responses in cry1cry2 background 1), as a novel component of phyB signaling in Arabidopsis. RRC1 has a C-terminal arginine/serine-rich (RS) domain that is generally important for the regulation of alternative splicing. Whereas rrc1 hypomorphic mutant alleles produce truncated RRC1 proteins that lack the C-terminal region, including the RS domain, and exhibit splicing defects and reduced phyB signaling, the rrc1-4 null allele additionally displays pleiotropic developmental abnormalities with more severe splicing defects. Here, we show that transgenic Arabidopsis plants that express truncated RRC1 lacking the RS domain in the rrc1-4 null allele background exhibited the same phenotype as the hypomorphic alleles. Hence, we conclude that deletion of the RS domain of RRC1 reduces phyB signaling, probably due to aberrant regulation of alternative splicing of target genes.
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Affiliation(s)
| | | | - Ken Matsuoka
- Faculty of Agriculture; Kyushu University; Fukuoka, Japan
- Biotron Application Center; Kyushu University; Fukuoka, Japan
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Rasul S, Wendehenne D, Jeandroz S. Study of oligogalacturonides-triggered nitric oxide (NO) production provokes new questioning about the origin of NO biosynthesis in plants. Plant Signal Behav 2012; 7:1031-3. [PMID: 22827951 PMCID: PMC3474673 DOI: 10.4161/psb.20658] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
We investigated the production and function of nitric oxide (NO) in Arabidopsis thaliana leaf discs as well as whole plants elicited by oligogalacturonides (OGs). Using genetic, biochemical and pharmacological approaches, we provided evidence that OGs induced a Nitrate Reductase (NR)-dependent NO production together with an increased NR activity and NR transcripts accumulation. In addition, NO production was sensitive to the mammalian NOS inhibitor L-NAME. Intriguingly, L-NAME impaired OG-induced NR activity and did not further affect the remaining OG-induced NO production in the nia1nia2 mutant. These data suggest that the L-arginine and NR pathways, co-involved in NO production, do not work independently. Taking account these new data, we propose scenarios to explain NO production in response to biotic stress.
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Affiliation(s)
- Sumaira Rasul
- AgroSup; UMR 1347 Agroécologie; Dijon, France
- Université de Bourgogne; UMR1347 Agroécologie; Dijon, France
- ERL CNRS 6300; BP 86510; Dijon, France
| | - David Wendehenne
- Université de Bourgogne; UMR1347 Agroécologie; Dijon, France
- ERL CNRS 6300; BP 86510; Dijon, France
| | - Sylvain Jeandroz
- AgroSup; UMR 1347 Agroécologie; Dijon, France
- ERL CNRS 6300; BP 86510; Dijon, France
- Correspondence to: Sylvain Jeandroz,
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29
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Acevedo-Hernández G, Oropeza-Aburto A, Herrera-Estrella L. A specific variant of the PHR1 binding site is highly enriched in the Arabidopsis phosphate-responsive phospholipase DZ2 coexpression network. Plant Signal Behav 2012; 7:914-7. [PMID: 22836502 PMCID: PMC3474684 DOI: 10.4161/psb.20749] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
PLDZ2 is a member of the Arabidopsis phospholipase D gene family that is induced in both shoot and root in response to phosphate (Pi) starvation. Recently, through deletion and gain-of-function analyses of the PLDZ2 promoter, we identified a 65 bp region (denominated enhancer EZ2) capable of conferring tissue-specific and low-Pi responses to a minimal inactive promoter. The EZ2 element contains two P1BS motifs, each of which is the binding site for PHR1 and related transcription factors. This structural organization is evolutionarily conserved in orthologous promoters within the rosid clade. To determine whether EZ2 is significantly over-represented in Arabidopsis genes coexpressed with PLDZ2, we constructed a PLDZ2 coexpression network containing 26 genes, almost half of them encoding enzymes or regulatory proteins involved in Pi recycling. A variant of the P1BS motif was found to be highly enriched in the promoter regions of these coexpressed genes, showing an EZ2-like arrangement in seven of them. No other motifs were significantly enriched. The over-representation of the EZ2 arrangement of P1BS motifs in the promoters of genes coexpressed with PLDZ2, suggests this unit has a particularly important role as a regulatory element in a coexpression network involved in the release of Pi from phospholipids and other molecules under Pi-limiting conditions.
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Affiliation(s)
- Gustavo Acevedo-Hernández
- Centro Universitario de la Ciénega; Universidad de Guadalajara (CUCI-UdeG); Ocotlan, Jalisco, Mexico
| | - Araceli Oropeza-Aburto
- Laboratorio Nacional de Genómica para la Biodiversidad del Centro de Investigación y de Estudios Avanzados del IPN; Irapuato, Guanajuato, Mexico
| | - Luis Herrera-Estrella
- Laboratorio Nacional de Genómica para la Biodiversidad del Centro de Investigación y de Estudios Avanzados del IPN; Irapuato, Guanajuato, Mexico
- Correspondence to: Luis Herrera-Estrella,
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Abstract
An abundant class of E3 ubiquitin ligases encodes the RING-finger domain. The RING finger binds to the E2 ubiquitin-conjugating enzyme and brings together both the E2 and substrate. It is predicted that 477 RING finger E3 ligases exist in Arabidopsis thaliana. A particular family among them, named Arabidopsis Tóxicos en Levadura (ATL), consists of 91 members that contain the RING-H2 variation and a hydrophobic domain located at the N-terminal end. Transmembrane E3 ligases are important in several biological processes. For instance, some transmembrane RING finger E3 ligases are main participants in the endoplasmic reticulum-associated degradation pathway that targets misfolded proteins. Functional analysis of a number of ATLs has shown that some of them regulate distinct pathways in plants. Several ATLs have been shown to participate in defense responses, while others play a role in the regulation of the carbon/nitrogen response during post-germinative seedling growth transition, in the regulation of cell death during root development, in endosperm development, or in the transition to flowering under short day conditions. The ATL family has also been instrumental in evolution studies for showing how gene families are expanded in plant genomes.
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Affiliation(s)
- Plinio Guzmán
- Departamento de Ingeniería Genética de Plantas Centro de Investigación y de Estudios Avanzados, Unidad Irapuato, Irapuato, México.
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Abstract
The Toc75 and OEP80 proteins reside in the chloroplast outer envelope membrane. Both are members of the Omp85 superfamily of β-barrel proteins, and both are essential in Arabidopsis plants with important roles throughout development. Toc75 forms the translocation channel of the TOC complex, which is responsible for importing nucleus-encoded proteins into chloroplasts, while the function of OEP80 remains uncertain. Deficiency of Toc75 in plants that have artificially reduced OEP80 levels suggests that the latter may be involved in the biogenesis of β-barrel proteins, in similar fashion to Omp85-related proteins in other systems. To elucidate the evolutionary relationship between the two proteins, we conducted a phylogenetic analysis using 48 sequences from diverse species. This indicated that Toc75 and OEP80 belong to sister groups in the Omp85 superfamily, and originate from a gene duplication in an ancient eukaryotic organism > 1.2 billion years ago. Our analysis also supports the notion that the Toc75 family has undergone a phase of neofunctionalization to accommodate the organelle's newly acquired need to import proteins.
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Affiliation(s)
- Mats Töpel
- Department of Plant and Environmental Sciences; Göteborg University; Göteborg, Sweden
| | - Qihua Ling
- Department of Biology; University of Leicester; Leicester, UK
| | - Paul Jarvis
- Department of Biology; University of Leicester; Leicester, UK
- Correspondence to: Paul Jarvis,
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32
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Abstract
The division site in both chloroplasts and bacteria is established by the medial placement of the FtsZ ring, a process that is in part regulated by the evolutionarily conserved components of the Min system. We recently showed that mechanosensitive ion channels influence FtsZ ring assembly in both Arabidopsis thaliana chloroplasts and in Escherichia coli; in chloroplasts they do so through the same genetic pathway as the Min system. Here we describe the effect of heterologous expression of the Arabidopsis MS channel homolog MSL2 on FtsZ ring placement in E. coli. We also discuss possible molecular mechanisms by which MS channels might influence chloroplast or bacterial division.
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Abstract
Glutathione (GSH) is a non-protein thiol compound which has been repeatedly reported to play an important role in plant responses during biotic stresses. However, our knowledge of glutathione-related molecular mechanisms underlying plant defense responses still remains limited. We first discovered that the Arabidopsis thaliana phytoalexin deficient 2-1 (pad2-1) mutant was linked to glutathione deficiency since the mutation was identified in the GSH1 gene encoding the first enzyme of glutathione biosynthesis: Glutamate Cysteine Ligase (GCL). Interestingly, this glutathione-deficient mutant pad2-1 also displays a high susceptibility to a wide range of invaders. We recently reported that the glutathione deficiency in pad2-1 is directly related to a low content of GCL protein. In parallel, we highlighted that the altered redox potential in pad2-1 upregulates the oxidative-stress marker genes GR1, GSTF6 and RbohD during infection with the hemibiotrophic oomycete Phytophthora brassicae. Moreover, the impairment of early signaling events such as plasma membrane depolarization, production of nitric oxide and reactive oxygen species also correlates with the reduced hypersensitive response (HR) observed during P. brassicae infection. Concerning the impaired salicylic acid (SA)-dependent pathway in pad2-1, our results indicated that transcripts of IsoChorismate Synthase1 (ICS1, a main enzyme of SA biosynthesis) do not accumulate in response to pathogen. In this review, we integrate previous knowledge and recent discoveries about pad2-1 to better understand the involvement of glutathione in the pad2-1 pleiotropic phenotype observed during biotic stresses.
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34
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Di Mauro MF, Iglesias MJ, Arce DP, Valle EM, Arnold RB, Tsuda K, Yamazaki KI, Casalongué CA, Godoy AV. MBF1s regulate ABA-dependent germination of Arabidopsis seeds. Plant Signal Behav 2012; 7:188-92. [PMID: 22353867 PMCID: PMC3405706 DOI: 10.4161/psb.18843] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
Transcriptional co-activators of the multiprotein bridging factor 1 (MBF1) controls gene expression by connecting transcription factors and the basal transcription machinery. In Arabidopsis thaliana functions of MBF1 genes have been related to stress tolerance and developmental alterations. Endogenous ABA plays a major role in the regulation of Arabidopsis seed dormancy and germination. Seed dormancy and ABA sensitivity are enhanced in ethylene insensitive mutants suggesting that ethylene signal transduction pathway is necessary to fully develop ABA-dependent germination. In this report we showed that a triple knock-down mutant for Arabidopsis MBF1 genes (abc-) has enhanced seed dormancy and displays hypersensitivity to exogenous ABA. In addition, higher ABA contents were detected in abc- seeds after imbibition. These evidences suggest a negative role of MBF1s genes in ABA-dependent inhibition of germination. The participation of MBF1s in ethylene signal transduction pathway is also discussed.
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Affiliation(s)
- María Florencia Di Mauro
- Instituto de Investigaciones Biológicas, Universidad Nacional de Mar del Plata; Mar del Plata, Argentina
| | - María José Iglesias
- Instituto de Investigaciones Biológicas, Universidad Nacional de Mar del Plata; Mar del Plata, Argentina
| | - Débora Pamela Arce
- Instituto de Biología Molecular y Celular de Rosario (IBR-CONICET); Facultad de Ciencias Bioquímicas y Farmacéuticas; Universidad Nacional de Rosario; Rosario, Argentina
| | - Estela Marta Valle
- Instituto de Biología Molecular y Celular de Rosario (IBR-CONICET); Facultad de Ciencias Bioquímicas y Farmacéuticas; Universidad Nacional de Rosario; Rosario, Argentina
| | - Roberto Benech Arnold
- Instituto de Investigaciones Fisiológicas y Ecológicas; Facultad de Agronomía; Universidad de Buenos Aires; Buenos Aires, Argentina
| | - Kenichi Tsuda
- Department of Plant Biology; Microbial and Plant Genomics Institute; University of Minnesota; St. Paul, MN USA
| | - Ken-ichi Yamazaki
- Laboratory of Environmental Molecular Biology; Graduate School of Environmental Earth Science; Hokkaido University; Kita-ku, Sapporo, Japan
| | - Claudia Anahí Casalongué
- Instituto de Investigaciones Biológicas, Universidad Nacional de Mar del Plata; Mar del Plata, Argentina
| | - Andrea Verónica Godoy
- Instituto de Investigaciones Biológicas, Universidad Nacional de Mar del Plata; Mar del Plata, Argentina
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35
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Šimková K, Kim C, Gacek K, Baruah A, Laloi C, Apel K. The chloroplast division mutant caa33 of Arabidopsis thaliana reveals the crucial impact of chloroplast homeostasis on stress acclimation and retrograde plastid-to-nucleus signaling. Plant J 2012; 69:701-12. [PMID: 22014227 PMCID: PMC3274639 DOI: 10.1111/j.1365-313x.2011.04825.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Retrograde plastid-to-nucleus signaling tightly controls and coordinates the nuclear and plastid gene expression that is required for plastid biogenesis and chloroplast activity. As chloroplasts act as sensors of environmental changes, plastid-derived signaling also modulates stress responses of plants by transferring stress-related signals and altering nuclear gene expression. Various mutant screens have been undertaken to identify constituents of plastid signaling pathways. Almost all mutations identified in these screens target plastid-specific but not extraplastidic functions. They have been suggested to define either genuine constituents of retrograde signaling pathways or components required for the synthesis of plastid signals. Here we report the characterization of the constitutive activator of AAA-ATPase (caa33) mutant, which reveals another way of how mutations that affect plastid functions may modulate retrograde plastid signaling. caa33 disturbs a plastid-specific function by impeding plastid division, and thereby perturbing plastid homeostasis. This results in preconditioning plants by activating the expression of stress genes, enhancing pathogen resistance and attenuating the capacity of the plant to respond to plastid signals. Our study reveals an intimate link between chloroplast activity and the susceptibility of the plant to stress, and emphasizes the need to consider the possible impact of preconditioning on retrograde plastid-to-nucleus signaling.
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Affiliation(s)
- Klára Šimková
- ETH Zurich, Institute of Plant Sciences, Switzerland
| | - Chanhong Kim
- Boyce Thompson Institute for Plant Research, Ithaca NY, USA
| | | | - Aiswarya Baruah
- ETH Zurich, Institute of Plant Sciences, Switzerland
- Boyce Thompson Institute for Plant Research, Ithaca NY, USA
| | - Christophe Laloi
- ETH Zurich, Institute of Plant Sciences, Switzerland
- Aix-Marseille Université, Lab Genet Biophys Plantes, Marseille, F-13009, France
- CNRS, UMR Biol Veget & Microbiol Environ, Marseille, F-13009, France
- CEA, DSV, IBEB, Marseille, F-13009, France
| | - Klaus Apel
- ETH Zurich, Institute of Plant Sciences, Switzerland
- Boyce Thompson Institute for Plant Research, Ithaca NY, USA
- Corresponding author: Klaus Apel, Boyce Thompson Institute for Plant Research, Tower Road, Ithaca, NY-14853-1801, USA. Tel.: 001-6072797734; ; Fax: 001-6072541242
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36
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Abstract
Aberrant microtubule organization has been recently recorded in dividing root cells of fra2 and lue1 p60-katanin Arabidopsis thaliana mutants. Here, we report similar defects in the bot1 and ktn1-2 mutants of the same plant, proposing that they constitute a consistent phenotype of p60-katanin mutants. In addition, we show that the Targeting Protein for Xklp2 (TPX2) protein co-localizes with microtubules on the surface of prophase nuclei of the mutants, probably participating in multipolar spindle assembly. As microtubule organization defects are not observed in metaphase/anaphase spindles and initiating phragmoplasts, we also discuss the putative association of the observed aberrations with the nuclear envelope and we emphasize on the mechanism of bipolar metaphase spindle organization in the mutants. It seems that chromosome-mediated spindle assembly, probably minimally dependent on microtubule severing by p60-katanin, dominates after nuclear envelope breakdown, restoring bipolarity.
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Affiliation(s)
- Emmanuel Panteris
- Department of Botany, School of Biology, Aristotle University, Thessaloniki, Greece.
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37
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Abstract
Cellular dedifferentiation is often observed in both plants and animals at an early step of wound-induced regeneration. Some plant species develop callus, a mass of unorganised cells, after wounding and this response is thought to involve cell dedifferentiation since callus cells are usually ready to exert totipotency, an ability to regenerate any new organ including somatic embryos. It is well established that a balance of the two plant hormones, auxin and cytokinin, is central in controlling plant cell dedifferentiation and subsequent redifferentiation but molecular mechanisms underlying these processes are still unclear. In a recent study we reported that an AP2/ERF transcription factor WOUND INDUCED DEDIFFERENTIATION 1 (WIND1) and its close homologs, WIND2–4, are induced by wounding and that they promote cell dedifferentiation in Arabidopsis. Our data show that WIND proteins are required to activate the local cytokinin response at the wound site.
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Affiliation(s)
| | - Masaru Ohme-Takagi
- Bioproduction Research Institute; National Institute of Advanced Industrial Science and Technology; Tsukuba, Japan
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38
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Clastre M, Papon N, Courdavault V, Giglioli-Guivarc’h N, St-Pierre B, Simkin AJ. Subcellular evidence for the involvement of peroxisomes in plant isoprenoid biosynthesis. Plant Signal Behav 2011; 6:2044-6. [PMID: 22080790 PMCID: PMC3337203 DOI: 10.4161/psb.6.12.18173] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The role of peroxisomes in isoprenoid metabolism, especially in plants, has been questioned in several reports. A recent study of Sapir-Mir et al. revealed that the two isoforms of isopentenyl diphosphate (IPP) isomerase, catalyzing the isomerisation of IPP to dimethylallyl diphosphate (DMAPP) are found in the peroxisome. In this addendum, we provide additional data describing the peroxisomal localization of 5-phosphomevalonate kinase and mevalonate 5-diphosphate decarboxylase, the last two enzymes of the mevalonic acid pathway leading to IPP. This finding was reinforced in our latest report showing that a short isoform of farnesyl diphosphate, using IPP and DMAPP as substrates, is also targeted to the organelle. Therefore, the classical sequestration of isoprenoid biosynthesis between plastids and cytosol/ER can be revisited by including the peroxisome as an additional isoprenoid biosynthetic compartment within plant cells.
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Affiliation(s)
- Marc Clastre
- Université François-Rabelais de Tours; EA2106 Biomolécules et Biotechnologies Végétales; Tours, France
| | - Nicolas Papon
- Université François-Rabelais de Tours; EA2106 Biomolécules et Biotechnologies Végétales; Tours, France
| | - Vincent Courdavault
- Université François-Rabelais de Tours; EA2106 Biomolécules et Biotechnologies Végétales; Tours, France
| | | | - Benoit St-Pierre
- Université François-Rabelais de Tours; EA2106 Biomolécules et Biotechnologies Végétales; Tours, France
| | - Andrew J. Simkin
- Université François-Rabelais de Tours; EA2106 Biomolécules et Biotechnologies Végétales; Tours, France
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39
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Tohge T, Kusano M, Fukushima A, Saito K, Fernie AR. Transcriptional and metabolic programs following exposure of plants to UV-B irradiation. Plant Signal Behav 2011; 6:1987-92. [PMID: 22112450 PMCID: PMC3337192 DOI: 10.4161/psb.6.12.18240] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
In order to adapt to environmental changes of light species and intensity, higher plants furnish complicate signaling systems such as the UVR/COP/HY5 cascade which links several diverse classes of photoreceptors. In addition UV-B light provokes accelerated production of UV-B protectants such as flavonoids and vitamins. Following intensive research efforts, genes in the UV-B signaling cascade have been characterized via forward genetics approaches following mutant screens relying on sensitivity to UV-B irradiation. However detailed processes of the linkage between light signaling and the upregulation of metabolite accumulation remain unclear. Here we review both the light signal cascades and metabolite pathways responding to UV-B exposure. Finally we generate co-expression network analysis using published data in order to find novel candidate genes which link light signaling and transcriptional regulation to metabolic biosynthesis in attempt to describe how these processes are interlinked.
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Affiliation(s)
- Takayuki Tohge
- RIKEN Plant Science Center; Yokohama, Japan
- Max-Planck Institute for Molecular Plant Physiology; Potsdam-Golm, Germany
- Correspondence to: Takayuki Tohge, or Alisdair R. Fernie,
| | | | | | - Kazuki Saito
- RIKEN Plant Science Center; Yokohama, Japan
- Graduate School of Pharmaceutical Sciences; Chiba University; Chiba, Japan
| | - Alisdair R. Fernie
- Max-Planck Institute for Molecular Plant Physiology; Potsdam-Golm, Germany
- Correspondence to: Takayuki Tohge, or Alisdair R. Fernie,
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40
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Abstract
Protein turnover is fundamental both for development and cellular homeostasis. The mechanisms responsible for the turnover of integral membrane proteins in plant cells are however still largely unknown. Recently, considerable attention has been devoted to the degradation of plasma membrane proteins. We have now studied the turnover of a tonoplast protein, the potassium channel TPK1, in fully differentiated Arabidopsis leaf cells and showed that its degradation occurs upon internalization into the vacuole. Here, we discuss the possible mechanisms and triggering events involved.
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41
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Chanroj S, Lu Y, Padmanaban S, Nanatani K, Uozumi N, Rao R, Sze H. Plant-specific cation/H+ exchanger 17 and its homologs are endomembrane K+ transporters with roles in protein sorting. J Biol Chem 2011; 286:33931-41. [PMID: 21795714 PMCID: PMC3190763 DOI: 10.1074/jbc.m111.252650] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2011] [Revised: 07/08/2011] [Indexed: 11/30/2022] Open
Abstract
The complexity of intracellular compartments in eukaryotic cells evolved to provide distinct environments to regulate processes necessary for cell proliferation and survival. A large family of predicted cation/proton exchangers (CHX), represented by 28 genes in Arabidopsis thaliana, are associated with diverse endomembrane compartments and tissues in plants, although their roles are poorly understood. We expressed a phylogenetically related cluster of CHX genes, encoded by CHX15-CHX20, in yeast and bacterial cells engineered to lack multiple cation-handling mechanisms. Of these, CHX16-CHX20 were implicated in pH homeostasis because their expression rescued the alkaline pH-sensitive growth phenotype of the host yeast strain. A smaller subset, CHX17-CHX19, also conferred tolerance to hygromycin B. Further differences were observed in K(+)- and low pH-dependent growth phenotypes. Although CHX17 did not alter cytoplasmic or vacuolar pH in yeast, CHX20 elicited acidification and alkalization of the cytosol and vacuole, respectively. Using heterologous expression in Escherichia coli strains lacking K(+) uptake systems, we provide evidence for K(+) ((86)Rb) transport mediated by CHX17 and CHX20. Finally, we show that CHX17 and CHX20 affected protein sorting as measured by carboxypeptidase Y secretion in yeast mutants grown at alkaline pH. In plant cells, CHX20-RFP co-localized with an endoplasmic reticulum marker, whereas RFP-tagged CHX17-CHX19 co-localized with prevacuolar compartment and endosome markers. Together, these results suggest that in response to environmental cues, multiple CHX transporters differentially modulate K(+) and pH homeostasis of distinct intracellular compartments, which alter membrane trafficking events likely to be critical for adaptation and survival.
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Affiliation(s)
- Salil Chanroj
- From the Department of Cell Biology and Molecular Genetics and the Maryland Agricultural Experiment Station, University of Maryland, College Park, Maryland 20742
| | - Yongxian Lu
- From the Department of Cell Biology and Molecular Genetics and the Maryland Agricultural Experiment Station, University of Maryland, College Park, Maryland 20742
| | - Senthilkumar Padmanaban
- From the Department of Cell Biology and Molecular Genetics and the Maryland Agricultural Experiment Station, University of Maryland, College Park, Maryland 20742
| | - Kei Nanatani
- the Department of Biomolecular Engineering, Graduate School of Engineering, Tohoku University, Sendai 980-8579, Japan
| | - Nobuyuki Uozumi
- the Department of Biomolecular Engineering, Graduate School of Engineering, Tohoku University, Sendai 980-8579, Japan
| | - Rajini Rao
- the Department of Physiology, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, and
| | - Heven Sze
- From the Department of Cell Biology and Molecular Genetics and the Maryland Agricultural Experiment Station, University of Maryland, College Park, Maryland 20742
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Kim SW, Kim HJ, Kim JH, Kwon YK, Ahn MS, Jang YP, Liu JR. A rapid, simple method for the genetic discrimination of intact Arabidopsis thaliana mutant seeds using metabolic profiling by direct analysis in real-time mass spectrometry. Plant Methods 2011; 7:14. [PMID: 21658279 PMCID: PMC3138417 DOI: 10.1186/1746-4811-7-14] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/18/2011] [Accepted: 06/10/2011] [Indexed: 05/30/2023]
Abstract
BACKGROUND Efficient high throughput screening systems of useful mutants are prerequisite for study of plant functional genomics and lots of application fields. Advance in such screening tools, thanks to the development of analytic instruments. Direct analysis in real-time (DART)-mass spectrometry (MS) by ionization of complex materials at atmospheric pressure is a rapid, simple, high-resolution analytical technique. Here we describe a rapid, simple method for the genetic discrimination of intact Arabidopsis thaliana mutant seeds using metabolic profiling by DART-MS. RESULTS To determine whether this DART-MS combined by multivariate analysis can perform genetic discrimination based on global metabolic profiling, intact Arabidopsis thaliana mutant seeds were subjected to DART-MS without any sample preparation. Partial least squares-discriminant analysis (PLS-DA) of DART-MS spectral data from intact seeds classified 14 different lines of seeds into two distinct groups: Columbia (Col-0) and Landsberg erecta (Ler) ecotype backgrounds. A hierarchical dendrogram based on partial least squares-discriminant analysis (PLS-DA) subdivided the Col-0 ecotype into two groups: mutant lines harboring defects in the phenylpropanoid biosynthetic pathway and mutants without these defects. These results indicated that metabolic profiling with DART-MS could discriminate intact Arabidopsis seeds at least ecotype level and metabolic pathway level within same ecotype. CONCLUSION The described DART-MS combined by multivariate analysis allows for rapid screening and metabolic characterization of lots of Arabidopsis mutant seeds without complex metabolic preparation steps. Moreover, potential novel metabolic markers can be detected and used to clarify the genetic relationship between Arabidopsis cultivars. Furthermore this technique can be applied to predict the novel gene function of metabolic mutants regardless of morphological phenotypes.
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Affiliation(s)
- Suk Weon Kim
- Biological Resource Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), 125 Gwahak-ro, Yuseong-gu, Daejeon, 305-806, Korea
| | - Hye Jin Kim
- Division of Pharmacognosy, Kyung Hee University, 1 Hoegi dong Dongdaemun-Gu, Seoul, 130-701, Korea
| | - Jong Hyun Kim
- Plant Systems Engineering Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), 125 Gwahak-ro, Yuseong-gu, Daejeon, 305-806, Korea
| | - Yong Kook Kwon
- Biological Resource Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), 125 Gwahak-ro, Yuseong-gu, Daejeon, 305-806, Korea
| | - Myung Suk Ahn
- Plant Systems Engineering Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), 125 Gwahak-ro, Yuseong-gu, Daejeon, 305-806, Korea
| | - Young Pyo Jang
- Division of Pharmacognosy, Kyung Hee University, 1 Hoegi dong Dongdaemun-Gu, Seoul, 130-701, Korea
| | - Jang R Liu
- Plant Systems Engineering Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), 125 Gwahak-ro, Yuseong-gu, Daejeon, 305-806, Korea
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Kurepa J, Paunesku T, Vogt S, Arora H, Rabatic BM, Lu J, Wanzer MB, Woloschak GE, Smalle JA. Uptake and distribution of ultrasmall anatase TiO2 Alizarin red S nanoconjugates in Arabidopsis thaliana. Nano Lett 2010; 10:2296-302. [PMID: 20218662 PMCID: PMC2912449 DOI: 10.1021/nl903518f] [Citation(s) in RCA: 200] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
While few publications have documented the uptake of nanoparticles in plants, this is the first study describing uptake and distribution of the ultrasmall anatase TiO(2) in the plant model system Arabidopsis. We modified the nanoparticle surface with Alizarin red S and sucrose and demonstrated that nanoconjugates traversed cell walls, entered into plant cells, and accumulated in specific subcellular locations. Optical and X-ray fluorescence microscopy coregistered the nanoconjugates in cell vacuoles and nuclei.
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Affiliation(s)
| | | | | | | | | | | | | | - Gayle E. Woloschak
- Corresponding authors: Prof. G. E. Woloschak, Departments of Radiation Oncology, Radiology, and Cell and Molecular Biology, Northwestern University, Feinberg School of Medicine, Chicago, IL 60611 (USA), . Prof. J. A. Smalle, Department of Plant and Soil Sciences, University of Kentucky, Lexington, KY 40546 (USA),
| | - Jan A. Smalle
- Corresponding authors: Prof. G. E. Woloschak, Departments of Radiation Oncology, Radiology, and Cell and Molecular Biology, Northwestern University, Feinberg School of Medicine, Chicago, IL 60611 (USA), . Prof. J. A. Smalle, Department of Plant and Soil Sciences, University of Kentucky, Lexington, KY 40546 (USA),
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Block MA, Douce R, Joyard J, Rolland N. Chloroplast envelope membranes: a dynamic interface between plastids and the cytosol. Photosynth Res 2007; 92:225-44. [PMID: 17558548 PMCID: PMC2394710 DOI: 10.1007/s11120-007-9195-8] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2007] [Accepted: 05/03/2007] [Indexed: 05/15/2023]
Abstract
Chloroplasts are bounded by a pair of outer membranes, the envelope, that is the only permanent membrane structure of the different types of plastids. Chloroplasts have had a long and complex evolutionary past and integration of the envelope membranes in cellular functions is the result of this evolution. Plastid envelope membranes contain a wide diversity of lipids and terpenoid compounds serving numerous biochemical functions and the flexibility of their biosynthetic pathways allow plants to adapt to fluctuating environmental conditions (for instance phosphate deprivation). A large body of knowledge has been generated by proteomic studies targeted to envelope membranes, thus revealing an unexpected complexity of this membrane system. For instance, new transport systems for metabolites and ions have been identified in envelope membranes and new routes for the import of chloroplast-specific proteins have been identified. The picture emerging from our present understanding of plastid envelope membranes is that of a key player in plastid biogenesis and the co-ordinated gene expression of plastid-specific protein (owing to chlorophyll precursors), of a major hub for integration of metabolic and ionic networks in cell metabolism, of a flexible system that can divide, produce dynamic extensions and interact with other cell constituents. Envelope membranes are indeed one of the most complex and dynamic system within a plant cell. In this review, we present an overview of envelope constituents together with recent insights into the major functions fulfilled by envelope membranes and their dynamics within plant cells.
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Gutierrez RA, Ewing RM, Cherry JM, Green PJ. Identification of unstable transcripts in Arabidopsis by cDNA microarray analysis: rapid decay is associated with a group of touch- and specific clock-controlled genes. Proc Natl Acad Sci U S A 2002; 99:11513-8. [PMID: 12167669 PMCID: PMC123287 DOI: 10.1073/pnas.152204099] [Citation(s) in RCA: 174] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2002] [Indexed: 11/18/2022] Open
Abstract
mRNA degradation provides a powerful means for controlling gene expression during growth, development, and many physiological transitions in plants and other systems. Rates of decay help define the steady state levels to which transcripts accumulate in the cytoplasm and determine the speed with which these levels change in response to the appropriate signals. When fast responses are to be achieved, rapid decay of mRNAs is necessary. Accordingly, genes with unstable transcripts often encode proteins that play important regulatory roles. Although detailed studies have been carried out on individual genes with unstable transcripts, there is limited knowledge regarding their nature and associations from a genomic perspective, or the physiological significance of rapid mRNA turnover in intact organisms. To address these problems, we have applied cDNA microarray analysis to identify and characterize genes with unstable transcripts in Arabidopsis thaliana (AtGUTs). Our studies showed that at least 1% of the 11,521 clones represented on Arabidopsis Functional Genomics Consortium microarrays correspond to transcripts that are rapidly degraded, with estimated half-lives of less than 60 min. AtGUTs encode proteins that are predicted to participate in a broad range of cellular processes, with transcriptional functions being over-represented relative to the whole Arabidopsis genome annotation. Analysis of public microarray expression data for these genes argues that mRNA instability is of high significance during plant responses to mechanical stimulation and is associated with specific genes controlled by the circadian clock.
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Affiliation(s)
- Rodrigo A Gutierrez
- Department of Energy Plant Research Laboratory, Michigan State University, East Lansing, MI 48824-1312, USA
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