Staff Profiles

Supervision

• I have supervised more than 25 PhD and DPhil students at Oxford Brookes University and the University of Oxford. I currently support the supervision of two PhD students

I am a member of the Cell Biology Research Group at Oxford Brookes, working with Verena Kriechbaumer and Katja Graumann. I specialise in the study of the plant nuclear envelope. Our group has research partnerships with Ohio State University (Visiting Professor Iris Meier, https://molgen.osu.edu/people/meier.56, and with Visiting Professor Christophe Tatout (Universite Clermont Auvergne, UCA, https://www.gred-clermont.fr/directory/member/christophe-tatout/). Our current projects include the study of protein protein interactions at the endoplasmic reticulum and nuclear envelope; the role of mid-SUN proteins; use of artificial intelligence methods to quantify nuclear shape and structure (co-tutelle with UCA) and study of the ER:NE interface. We use a range of techniques and specialise in light microscopy applications and live cell imaging. As part of the Indepth COST Action, https://www.brookes.ac.uk/indepth/, we disseminate our work through our European partnership as well as through annual meetings of the Society for Experimental Biology and in our publications.  We host the web site of Indepth (https://www.brookes.ac.uk/indepth/) and its training and methodological resource, the Indepth Academy (https://www.brookes.ac.uk/indepth/indepth-academy/)

Research group membership

Cell and Developmental Biology; Plant Cell Biology

Research grants and awards

Impact of Nuclear Domains on Gene Expression and Plant Traits (led by University Clermont-Ferrand) Research Network Evans, David Edgar (Hl Dept of Biological & Medical Sciences) (01/09/2017 - 31/08/2023) Funder: COST Association (Previous awards: Leverhulme Trust, BBSRC, Royal Society)

Research projects

The role of mid-SUN proteins in the plant nuclear envelope and endoplasmic reticulum

Use of artificial intelligence techniques to quantify nuclear stucture and dynamics (with UCA Clermont Auvergne)

Research impact

The nuclear envelope (NE) is of key importance in regulating the function of the nucleus. Chromosome territories are created by interaction with it with associated gene regulation; chromatin is structured by proteins which attach to the NE and the whole nucleus is positioned in disease and development by proteins interfacing with the NE. The role of the NE is therefore being explored to enhance transformation of plant material and to enhance disease and drought resistance. Our Research Group has contributed the discovery and characterisation of a range of proteins central to these interactions; focussing on components of the plant Linker of Nucleoskeleton and Cytoskeleton (LINC) complex, we have identified the key roles of inner nuclear envelope located SUN domain proteins and outer nuclear envelope KASH domain proteins and demonstrated their functions in creating a bridging complex at the NE. Through the Indepth COST Action, this work is being disseminated and applied in understanding genetics and epigenetics of crops and provides fundamental information for understanding the importance of the structure of the nucleus in defining plant traits.

Further information

https://doi.org/10.24384/IPNC

https://www.brookes.ac.uk/indepth/

Journal articles

• Evans, DE, 'Editorial for the SEB 2020 special issue ‘dynamic organisation of the nucleus across kingdoms’'
  Nucleus 12 (1) (2021) pp.42-43
  ISSN: 1949-1034 eISSN: 1949-1042
  Website 
• Graumann K, Evans DE, 'Growing the nuclear envelope proteome'
  Nature Plants 6 (2020) pp.740-741
  ISSN: 2055-026X eISSN: 2055-0278
  Abstract

  Identifying protein components of the nuclear envelope is a slow and challenging process. Now a proximity labelling technique adapted for plants reveals novel protein components in this under-researched membrane.
  

  Website 
• Hodson MJ, Evans DE, 'Aluminium/silicon interactions in higher plants- an update'
  Journal of Experimental Botany 71 (21) (2020) pp.6719-6729
  ISSN: 0022-0957 eISSN: 1460-2431
  Abstract

  Aluminium (Al) and silicon (Si) are abundant in soils, but their availability for plant uptake is limited by low solubility. However, Al toxicity is a major problem in naturally occurring acid soils and in soils affected by acidic precipitation. When, in 1995, we reviewed this topic for the Journal of Experimental Botany, it was clear that under certain circumstances soluble Si could ameliorate the toxic effects of Al, an effect mirrored in organisms beyond the plant kingdom. In the 25 years since our review, it has become evident that the amelioration phenomenon occurs in the root apoplast, with the formation of hydroxyaluminosilicates being part of the mechanism. A much better knowledge of the molecular basis for Si and Al uptake by plants and of Al toxicity mechanisms has been developed. However, relating this work to amelioration by Si is at an early stage. It is now clear that co-deposition of Al and Si in phytoliths is a fairly common phenomenon in the plant kingdom, and this may be important in detoxification of Al. Relatively little work on Al/Si interactions in field situations has happened in the last 25 years, and this is a key area for future development

  Website 
• Evans DE, Mermet S, Tatout C, 'Advancing knowledge of the plant nuclear periphery and its application for crop science.'
  Nucleus x (2020)
  ISSN: 1949-1034 eISSN: 1949-1042
  Website 
• Groves NR, McKenna JF, Evans DE, Graumann K, Meier I, 'A nuclear localization signal targets tail-anchored membrane proteins to the inner nuclear envelope in plants.'
  Journal of Cell Science 132 (2019)
  ISSN: 0021-9533 eISSN: 1477-9137
  Abstract

  Protein targeting to the inner nuclear membrane (INM) is one of the least understood protein targeting pathways. INM proteins are important for chromatin organization, nuclear morphology and movement, meiosis, and have been implicated in human diseases. In opisthokonts, one mechanism is transport-factor mediated trafficking, in which nuclear localization signals (NLSs) function in nuclear import of transmembrane proteins. To explore if this pathway exists in plants, we fused the SV40 NLS to a plant ER tail-anchored protein and showed that the GFP-tagged fusion protein was significantly enriched at the NE of leaf epidermal cells. Airyscan sub-diffraction limited confocal microscopy showed that it displays localization consistent with an INM protein. Nine different monopartite and bipartite NLSs from plants and opisthokonts, fused to a chimeric tail-anchored membrane protein, were all sufficient for NE enrichment and both monopartite or bipartite NLSs were sufficient for trafficking to the INM. Tolerance for different linker lengths and protein conformations suggests that INM trafficking rules might differ from those in opisthokonts. The INM proteins developed here can be used to target new functionalities to the plant nuclear periphery.
  

  Website 
• Pradillo M, Evans DE, Graumann K, 'The nuclear envelope in higher plant mitosis and meiosis'
  Nucleus 10 (1) (2019) pp.55-66
  ISSN: 1949-1034 eISSN: 1949-1042
  Abstract

  Mitosis and meiosis in higher plants involves significant reconfiguration of the nuclear envelope and the proteins that interact with it. The dynamic series of events involves a range of interactions, movement, breakdown and reformation of this complex system. Recently, progress has been made in identifying and characterising the protein and membrane interactome that performs these complex tasks, including constituents of the nuclear envelope, the cytoskeleton, nucleoskeleton and chromatin. This review will present current understanding of these interactions and advances in knowledge of the processes for the breakdown and reformation of the nuclear envelope during cell divisions in plants. 

  Website 
• Evans DE, Graumann K, 'The Linker of Nucleoskeleton and Cytoskeleton Complex in higher plants'
  Annual Plant Reviews 1 (1) (2018) pp.1-17
  ISSN: 1460-1494
  Abstract This linker of nucleoskeleton and cytoskeleton (LINC) complex provides a multifunctional bridge across the nuclear envelope, connection nucleoskeleton and cytoskeleton. This review considers the evidence for a LINC complex in higher plants and describes its key components, their functions and interactions. Evidence is presented that the complex is based on two families of Sad1/UNC84 homology (SUN) domain proteins in the inner nuclear envelope (C-ter SUNs and mid-SUNs) and three major groups of Klarsicht/ANC-1/Syne homology (KASH) domain proteins, WPP-domaininteracting proteins (WIPs), SUN-interacting nuclear envelope proteins
  (SINEs) and Toll Interleukin Receptor domain KASH protein (TIK). Recent advances in analysing the function of the complex in establishing nuclear shape and size, in nuclear movement and in connecting nucleoskeleton and cytoskeleton is described, together with its role in mitosis and meiosis. Website 
• Meier I, Richards EJ, Evans DE, 'Cell Biology of the Plant Nucleus'
  Annual Review of Plant Biology 68 (2017) pp.139-172
  ISSN: 1543-5008
  Abstract The eukaryotic nucleus is enclosed by the nuclear envelope, which is perforated by the nuclear pores, the gateways of macromolecular exchange between the nucleoplasm and cytoplasm. The nucleoplasm is organized in a complex three-dimensional fashion that changes over time and in response to stimuli. Within the cell, the nucleus must be viewed as an organelle (albeit a gigantic one) that is a recipient of cytoplasmic forces and capable of morphological and positional dynamics. The most dramatic reorganization of this organelle occurs during mitosis and meiosis. Although many of these aspects are less well understood for the nuclei of plants than for those of animals or fungi, several recent discoveries have begun to place our understanding of plant nuclei firmly into this broader cell-biological context.Website 
• Evans DE, Meier I, Graumann K, 'Editorial for the SEB Brighton Special Issue: Dynamic organization of the nucleus'
  Nucleus 8 (1) (2017) pp.1-1
  ISSN: 1949-1034 eISSN: 1949-1042
  Abstract EditorialWebsite 
• Poulet A, Duc C, Voisin M, Desset S, Tutois S, Vanrobays E, Benoit M, Evans DE, Probst AV, Tatout C, 'The LINC complex contributes to heterochromatin organisation and transcriptional gene silencing in plants'
  Journal of Cell Science 130 (3) (2017) pp.590-601
  ISSN: 0021-9533 eISSN: 1477-9137
  Abstract The LInker of Nucleoskeleton and Cytoskeleton (LINC) complex is an evolutionary well-conserved protein bridge connecting the cytoplasmic and nuclear compartments across the nuclear membrane. While recent data support its function in nuclear morphology and meiosis, its implication in chromatin organisation has not been studied in plants. Here 3D imaging methods have been used to investigate nuclear morphology and chromatin organisation in interphase nuclei of the model plant Arabidopsis thaliana, in which heterochromatin cluster in conspicuous chromatin domains called chromocentres. Chromocentres form a repressive chromatin environment contributing to transcriptional silencing of repeated sequences, a general mechanism needed for genome stability. Quantitative measurements of 3D position of chromocentres indicate their close proximity to the nuclear periphery but that their position varies with nuclear volume and can be altered in specific mutants affecting the LINC complex. Finally we propose that the plant LINC complex contributes to proper heterochromatin organisation and positioning at the nuclear periphery, since its alteration is associated with the release of transcriptional silencing as well as decompaction of heterochromatic sequences. Website 
• Poulet A, Probst AV, Graumann K, Tatout C, Evans DE, 'Exploring the evolution of the proteins of the plant nuclear envelope'
  Nucleus 8 (1) (2016) pp.46-59
  ISSN: 1949-1034 eISSN: 1949-1042
  Abstract In this study, we explore the plasticity during evolution of proteins of the higher plant nuclear envelope (NE) from the most ancestral plant species to advanced angiosperms. The higher
  plant NE contains a functional Linker of Nucleoskeleton and Cytoskeleton (LINC) complex based on conserved Sad1-Unc84 (SUN) domain proteins and plant specific Klarsicht/Anc1/Syne homology (KASH) domain proteins. Recent evidence suggests the presence of a plant lamina underneath the inner membrane and various coiled-coil proteins have been hypothesised to be associated with it including Crowded Nuclei (CRWN; also termed LINC and NMCP), Nuclear Envelope Associated Protein (NEAP) protein families as well as the CRWN binding protein KAKU4. SUN domain proteins appear throughout with a key role for mid-SUN proteins suggested. Evolution of KASH domain proteins has resulted in increasing complexity, with some appearing in all species considered, while other KASH proteins are progressively gained during evolution. Failure to identify CRWN homologs in unicellular organisms included in the study and their presence in plants leads us to speculate that convergent evolution may have occurred in the formation of the lamina with each kingdom having new proteins such as the Lamin B receptor (LBR) and Lamin-Emerin-Man1 (LEM) domain proteins (animals) or NEAPs and KAKU4 (plants). Our data support a model in which increasing complexity at the nuclear envelope occurred through the plant lineage and suggest a key role for mid-SUN proteins as an early and essential component of the nuclear envelope. 
  Website 
• Pawar V, Poulet A, Détourné G, Tatout C, Vanrobays E, Evans DE, Graumann K, 'A novel family of plant nuclear envelope associated proteins'
  Journal of Experimental Botany 67 (19) (2016) pp.5699-5710
  ISSN: 0022-0957 eISSN: 1460-2431
  Abstract This paper describes the characterisation of a new family of higher plant nuclear envelope associated proteins (NEAPs) that interact with proteins of the nuclear envelope. In the model plant Arabidopsis thaliana, the family consists of three genes expressed ubiquitously (AtNEAP1-3) and a pseudogene (AtNEAP4). NEAPs consist of extensive coiled-coil domains, followed by a nuclear localisation signal and a C-terminal predicted transmembrane domain. Domain deletion mutants confirm the presence of a functional nuclear localisation signal and transmembrane domain. AtNEAP proteins localise to the nuclear periphery as part of stable protein complexes, are able to form homo- and heteromers and interact with the SUN domain proteins AtSUN1 and AtSUN2, involved in the Linker of Nucleoskeleton and Cytoskeleton (LINC) complex. An A. thaliana cDNA library screen identified a putative transcription factor called AtbZIP18 as a novel interactor of AtNEAP1, which suggest a connection between NEAP and chromatin. An Atneap1 Atneap3 double knock out mutant showed reduced root growth and altered nuclear morphology and chromatin structure. Thus AtNEAPs are suggested as INM anchored coiled-coil proteins with roles in maintaining nuclear morphology and chromatin structure.
   
  Website 
• Smith S, Galinha C, Desset S, Tolmie F, Evans D, Tatout C, Graumann K, 'Marker gene tethering by nucleoporins affects gene expression in plants'
  Nucleus 6 (6) (2015) pp.471-478
  ISSN: 1949-1034 eISSN: 1949-1042
  Abstract

  In non-plant systems, chromatin association with the nuclear periphery affects gene expression, where interactions with nuclear envelope proteins can repress and interactions with nucleoporins can enhance transcription. In plants, both hetero- and euchromatin can localise at the nuclear periphery, but the effect of proximity to the nuclear periphery on gene expression remains largely unknown. This study explores the putative function of Seh1 and Nup50a nucleoporins on gene expression by using the Lac Operator / Lac Repressor (LacI-LacO) system adapted to Arabidopsis thaliana. We used LacO fused to the luciferase reporter gene (LacO:Luc) to investigate whether binding of the LacO:Luc transgene to nucleoporin:LacI protein fusions alters luciferase expression. Two separate nucleoporin-LacI-YFP fusions were introduced into single insert, homozygous LacO:Luc Arabidopsis plants. Homozygous plants carrying LacO:Luc and a single insert of either Seh1-LacI-YFP or Nup50a-LacI-YFP were tested for luciferase activity and compared to plants containing LacO:Luc only. Seh1-LacI-YFP increased, while Nup50a-LacI-YFP decreased luciferase activity. Seh1-LacI-YFP accumulated at the nuclear periphery as expected, while Nup50a-LacI-YFP was nucleoplasmic and was not selected for further study. Protein and RNA levels of luciferase were quantified by western blotting and RT-qPCR, respectively. Increased luciferase activity in LacO:Luc+Seh1-LacI-YFP plants was correlated with increased luciferase protein and RNA levels. This change of luciferase expression was abolished by disruption of LacI-LacO binding by treating with IPTG in young seedlings, rosette leaves and inflorescences. This study suggests that association with the nuclear periphery is involved in the regulation of gene expression in plants.

  Website 
• Varas J, Graumann K, Osman K, Pradillo M, Evans DE, Santos JL, Armstrong SJ, 'Absence of SUN1 and SUN2 proteins in Arabidopsis thaliana leads to a delay in meiotic progression and defects in synapsis and recombination'
  Plant Journal 81 (2) (2015) pp.329-346
  ISSN: 0960-7412 eISSN: 1365-313X
  Abstract

  The movement of chromosomes during meiosis involves location of their telomeres at the inner surface of the nuclear envelope. Sad1/UNC-84 (SUN) domain proteins are inner nuclear envelope proteins that are part of complexes linking cytoskeletal elements with the nucleoskeleton, connecting telomeres to the force-generating mechanism in the cytoplasm. These proteins play a conserved role in chromosome dynamics in eukaryotes. Homologues of SUN domain proteins have been identified in several plant species. In Arabidopsis thaliana, two proteins that interact with each other, named AtSUN1 and AtSUN2, have been identified.
  Immunolocalization using antibodies against AtSUN1 and AtSUN2 proteins revealed that they were associated with the nuclear envelope during meiotic prophase I. Analysis of the double mutant Atsun1-1 Atsun2-2 has revealed severe meiotic defects, namely a delay in the progression of meiosis, absence of full synapsis, the presence of unresolved interlock-like structures, and a reduction in the mean cell chiasma frequency. We propose that in Arabidopsis thaliana, overlapping functions of SUN1 and SUN2 ensure normal meiotic recombination and synapsis.

  Website 
• Tatout C, Evans DE, Vanrobays E, Probst AV, Graumann K, 'The plant LINC complex at the nuclear envelope'
  Chromosome Research 22 (2) (2014) pp.241-252
  ISSN: 0967-3849 eISSN: 1573-6849
  Abstract Significant advances in understanding the plant nuclear envelope have been made over the past few years; indeed, knowledge of the protein network at the nuclear envelope is rapidly growing. One such network, the linker of nucleoskeleton and cytoskeleton (LINC) complex, is known in animals to connect chromatin to the cytoskeleton through the nuclear envelope. The LINC complex is made of Sad1/Unc84 (SUN) and Klarsicht/Anc1/Syne1 homology (KASH) proteins which have been recently characterized in plants. SUN proteins are located within the inner nuclear membrane, while the KASH proteins are included into the outer nuclear membrane. SUN and KASH domains interact and bridge the two nuclear membranes. In Arabidopsis, KASH proteins also interact with the tryptophan-proline-proline (WPP) domain-interacting tail-anchored protein 1 (WIT1), associated with the nuclear pore complex and with myosin XI-i which directly interacts with the actin cytoskeleton. Although evidence for a plant LINC complex connecting the nucleus to the cytoskeleton is growing, its interaction with chromatin is still unknown, but knowledge gained from animal models strongly suggests its existence in plants. Possible functions of the plant LINC complex in cell division, nuclear shape, and chromatin organization are discussed.Website 
• Evans DE, Pawar V, Smith SJ, Graumann K, 'Protein interactions at the higher plant nuclear envelope: evidence for a linker of nucleoskeleton and cytoskeleton complex'
  Frontiers in Plant Science 5 (183) (2014)
  ISSN: 1664-462X eISSN: 1664-462X
  Abstract

  Following the description of SAD1/UNC84 (SUN) domain proteins in higher plants, evidence has rapidly increased that plants contain a functional linker of nucleoskeleton and cytoskeleton (LINC) complex bridging the nuclear envelope (NE). While the SUN domain proteins appear to be highly conserved across kingdoms, other elements of the complex are not and some key components and interactions remain to be identified. This mini review examines components of the LINC complex, including proteins of the SUN domain family and recently identified plant Klarsicht/Anc/Syne-1 homology (KASH) domain proteins. First of these to be described were WIPs (WPP domain interacting proteins), which act as protein anchors in the outer NE. The plant KASH homologs are C-terminally anchored membrane proteins with the extreme C-terminus located in the nuclear periplasm; AtWIPs contain a highly conserved X-VPT motif at the C-terminus in contrast to PPPX in opisthokonts. The role of the LINC complex in organisms with a cell wall, and description of further LINC complex components will be considered, together with other potential plant-specific functions.

  Website 
• Graumann K, Vanrobays E, Tutois S, Probst AV, Evans DE, Tatout C, 'Characterization of two distinct subfamilies of SUN-domain proteins in Arabidopsis and their interactions with the novel KASH-domain protein AtTIK'
  Journal of Experimental Botany 65 (22) (2014) pp.6499-6512
  ISSN: 0022-0957 eISSN: 1460-2431
  Abstract

  SUN-domain proteins belong to a gene family including classical Cter-SUN and mid-SUN subfamilies differentiated by the position of the SUN domain within the protein. Although present in animal and plant species, mid-SUN proteins have so far remained poorly described. Here, we used a combination of genetics, yeast two-hybrid and in planta transient expression methods to better characterize the SUN family in Arabidopsis thaliana. First, we validated the mid-SUN protein subfamily as a monophyletic group conserved from yeast to plant. Arabidopsis Cter-SUN (AtSUN1 and AtSUN2) and mid-SUN (AtSUN3 and AtSUN4) proteins expressed as fluorescent protein fusions are membrane-associated and localize to the nuclear envelope (NE) and endoplasmic reticulum. However, only the Cter-SUN subfamily is enriched at the NE. We investigated interactions in and between members of the two subfamilies and identified the coiled-coil domain as necessary for mediating interactions. The functional significance of the mid-SUN subfamily was further confirmed in mutant plants as essential for early seed development and involved in nuclear morphology. Finally, we demonstrated that both subfamilies interact with the KASH domain of AtWIP1 and identified a new root-specific KASH-domain protein, AtTIK. AtTIK localizes to the NE and affects nuclear morphology. Our study indicates that Arabidopsis Cter-SUN and mid-SUN proteins are involved in a complex protein network at the nuclear membranes, reminiscent of the LInker of Nucleoskeleton and Cytoskeleton (LINC) complex found in other kingdoms.

  Website 
• Zhou X, Graumann K, Evans D, Meier I, 'Novel plant SUN-KASH bridges are involved in RanGAP anchoring and nuclear shape determination'
  Journal of Cell Biology 196 (2) (2012) pp.203-211
  ISSN: 0021-9525
  Abstract

  Inner nuclear membrane Sad1/UNC-84 (SUN) proteins interact with outer nuclear membrane (ONM) Klarsicht/ANC-1/Syne homology (KASH) proteins, forming linkers of nucleoskeleton to cytoskeleton conserved from yeast to human and involved in positioning of nuclei and chromosomes. Defects in SUN-KASH bridges are linked to muscular dystrophy, progeria, and cancer. SUN proteins were recently identified in plants, but their ONM KASH partners are unknown. Arabidopsis WPP domain interacting proteins (AtWIPs) are plant-specific ONM proteins that redundantly anchor Arabidopsis RanGTPase-activating protein 1 (AtRanGAP1) to the nuclear envelope (NE). In this paper, we report that AtWIPs are plant-specific KASH proteins interacting with Arabidopsis SUN proteins (AtSUNs). The interaction is required for both AtWIP1 and AtRanGAP1 NE localization. AtWIPs and AtSUNs are necessary for maintaining the elongated nuclear shape of Arabidopsis epidermal cells. Together, our data identify the first KASH members in the plant kingdom and provide a novel function of SUN-KASH complexes, suggesting that a functionally diverged SUN-KASH bridge is conserved beyond the opisthokonts.

  Website 
• Prabagar S, Hodson M, Evans D, 'Silicon amelioration of aluminium toxicity and cell death in suspension cultures of Norway spruce (Picea abies (L.) Karst.)'
  Environmental and Experimental Botany 70 (40970) (2011) pp.266-276
  ISSN: 0098-8472
  Abstract A role for silicon (Si) in the amelioration of aluminium (Al) toxicity in gymnosperms is suggested by their codeposition in planta, including within needles. This study was designed to investigate Al/Si interactions at the cellular level using suspension cultures of Norway spruce. Toxic effects of Al were dependent on duration of Al exposure, concentration of Al. and pH. Toxicity was reduced when Si was present, and the effect was enhanced at pH 5.0 compared to pH 4.2. Study of the ultrastructure of Al-treated cells indicated that changes in cell wall thickening, degree of vacuolation, and the degeneration of mitochondria, Golgi bodies, ER and nucleus preceded cell death, and significant amelioration was noted when Si was also present. When the fluorescent dye Morin was employed to localise free Al, cells treated with Al and Si in combination showed less fluorescence than the cells treated with Al alone. Intensity of fluorescence depended on the concentration of Al, duration of treatment and pH. Notably, presence of Si reduced the concentration of free Al in the cell wall in parallel with amelioration of Al toxicity. We therefore propose that formation of aluminosilicate complexes in the wall and apoplasm provide a significant barrier to Al penetration and cell damage in Norway spruce.Website 
• Evans DE, Shvedunova M, Graumann K, 'The Nuclear Envelope in the Plant Cell Cycle: Structure, Function and Regulation'
  Annals of Botany 107 (2011) pp.1111-1118
  ISSN: 0305-7364 eISSN: 1095-8290
  Abstract Background. Higher plants are, like animals, organisms in which successful completion of the cell cycle requires the breakdown and reformation of the nuclear envelope in a highly controlled manner. Interestingly, however, while the structures and processes appear similar, there are remarkable differences in protein composition and function between plants and animals.
  
  Scope. Recent characterization of integral and associated components of the plant nuclear envelope has been instrumental in understanding its functions and behaviour. It is clear that protein interactions at the nuclear envelope are central to many processes in interphase and dividing cells and that the nuclear envelope has a key role in structural and regulatory events.
  
  Conclusion. Dissecting the mechanisms of nuclear envelope breakdown and reformation in plants is necessary before a better understanding of the functions of nuclear envelope components during the cell cycle can be gained.
  Website 
• Evans DE, Hawes C, 'Organelle biogenesis and positioning in plants'
  Biochemical Society Transactions 38 (3) (2010) pp.729-732
  ISSN: 0300-5127 eISSN: 1470-8752
  Abstract

  The biogenesis and positioning of organelles involves complex interacting processes and precise control. Progress in our understanding is being made rapidly as advances in analysing the nuclear and organellar genome and proteome combine with developments in live-cell microscopy and manipulation at the subcellular level. This paper introduces the collected papers resulting from Organelle Biogenesis and Positioning in Plants, the 2009 Biochemical Society Annual Symposium. Including papers on the nuclear envelope and all major organelles, it considers current knowledge and progress towards unifying themes that will elucidate the mechanisms by which cells generate the correct complement of organelles and adapt and change it in response to environmental and developmental signals.

  Website 
• Graumann K, Evans D, 'The plant nuclear envelope in focus'
  Biochemical Society Transactions 38 (1) (2010) pp.307-311
  ISSN: 0300-5127 eISSN: 1470-8752
  Abstract Recent progress in understanding the plant NE (nuclear envelope) has resulted from significant advances in identifying and characterizing the protein constituents of the membranes and nuclear pores. Here, we review recent findings on the membrane integral and membrane-associated proteins of the key domains of the NE, the pore domain and inner and outer NEs, together with information on protein targeting and NE function. Website 
• Graumann K, Runions J, Evans DE, 'Nuclear envelope proteins and their role in nuclear positioning and replication'
  Biochemical Society Transactions 38 (3) (2010) pp.741-746
  ISSN: 0300-5127 eISSN: 1470-8752
  Abstract

  Controlled movement Of the nucleus is important in a wide variety of plant cellular events Positioning involving intact nuclei occurs in cell division, development, tip growing systems such as the root hair and in response to stimuli, including light, touch and infection. Positioning is also essential in the division and replication of nuclear components, ranging from chromosome attachment to the breakdown and reformation of the nuclear envelope. Although description and understanding of the processes involved have advanced rapidly in recent years, significant gaps remain in our knowledge, especially concerning nuclear proteins involved in anchoring and interacting with cytoskeletal and nucleoskeletal elements involved in movement. In the present review, processes involving the movement and positioning of nuclei and nuclear components are described together with novel proteins implicated in nucleoskeletal and cytoskeletal interactions.

  Website 
• Graumann K, Runions J, Evans DE, 'Characterization of SUN-domain proteins at the higher plant nuclear envelope'
  Plant Journal 61 (1) (2010) pp.134-144
  ISSN: 0960-7412
  Abstract

  Sad1/UNC-84 (SUN)-domain proteins are inner nuclear membrane (INM) proteins that are part of bridging complexes linking cytoskeletal elements with the nucleoskeleton, and have been shown to be conserved in non-plant systems. In this paper, we report the presence of members of this family in the plant kingdom, and investigate the two Arabidopsis SUN-domain proteins, AtSUN1 and AtSUN2. Our results indicate they contain the highly conserved C-terminal SUN domain, and share similar structural features with animal and fungal SUN-domain proteins including a functional coiled-coil domain and nuclear localization signal. Both are expressed in various tissues with AtSUN2 expression levels relatively low but upregulated in proliferating tissues. Further, we found AtSUN1 and AtSUN2 expressed as fluorescent protein fusions, to localize to and show low mobility in the nuclear envelope (NE), particularly in the INM. Deletion of various functional domains including the N terminus and coiled-coil domain affect the localization and increase the mobility of AtSUN1 and AtSUN2. Finally, we present evidence that AtSUN1 and AtSUN2 are present as homomers and heteromers in vivo, and that the coiled-coil domains are required for this. The study provides evidence suggesting the existence of cytoskeletal-nucleoskeletal bridging complexes at the plant NE.

  Website 
• Evans D E, Irons S L, Graumann K, Runions C J, 'The plant nuclear envelope'
  Plant Cell Monographs 14 (2008) pp.9-28
  ISSN: 1861-1370 eISSN: 1861-1362
  Abstract The nuclear envelope is an important but poorly studied dynamic membrane system in plants. In particular, surprisingly little is known about the proteins of the higher plant nuclear envelope and their interactions. While structurally similar to the nuclear envelope of other kingdoms, unique properties suggest significant differences. For instance, plants lack sequence homologues of the lamins and instead of centrosomes the entire nuclear envelope surface acts as a microtubuleorganising centre. This chapter reviews the structure of the nuclear envelope in relation to its protein domains, namely the inner and outer membrane, and the pore domain. Recent advances in the characterisation of novel proteins from these domains are presented. In addition, new insights into mechanisms for the targeting and retention of nuclear envelope proteins are discussed. The nuclear envelope is of importance in cell signalling and evidence for physical nucleo-cytoskeletal linkage and for the nucleoplasm and periplasm as calcium signalling pools are considered. Finally, the behaviour of inner nuclear membrane proteins during the breakdown and reformation of the nuclear envelope in mitosis is discussed.Website 
• Evans D, Graumann K, 'Probing the plant nuclear envelope'
  Comparative Biochemistry and Physiology - Part A: Molecular & Integrative Physiology 150 (3) (2008) pp.199-200
  ISSN: 1095-6433
  Abstract he higher plant nuclear envelope (NE) remains poorly characterised. The plant NE resembles that of cells of other kingdoms; it is a double membrane structure, perforated by nuclear pores and linked to surrounding endoplasmic reticulum (ER). Despite this structural similarity, however, it shows a number of unique properties. Firstly, unlike yeast, but in common with most eukaryotes, plants show an unusually complex open cell division. Secondly, whereas in animal cells the structure of the NE is linked to a meshwork of nuclear lamins that constitute the nucleoskeleton, plants lack sequence homologues of the lamins. Thirdly, many of the proteins of the inner NE described in other species, the lamin B receptor (LBR), MAN1, otefin, nurim, emerin and LAPs 1 and 2, are not present in the plant nuclear envelope proteome. In this talk, we will present current knowledge on the structure and composition of the plant NE. Development of protein probes for the plant NE and their use for investigating NE targeting and NE dynamics will then be presented. The talk will conclude with discussion of areas where understanding of the dynamics of the plant NE and its relationship with other organelles is limited.Website 
• Runions J, Shvedunova M, Graumann K, Evans DE, 'Dynamic interrelationships of secretory pathway endomembranes during cell division'
  Comparative Biochemistry and Physiology - Part A: Molecular & Integrative Physiology 150 (3) (2008) pp.201-201
  ISSN: 1095-6433
  Website 
• Irons S, Graumann K, Runions J, Evans DE, 'Studies on the nuclear envelope targeting and retention of the N-terminus of the mammalian lamin B receptor expressed in plant cells'
  Comparative Biochemistry and Physiology - Part A: Molecular & Integrative Physiology 150 (3) (2008) pp.202-202
  ISSN: 1095-6433
  Abstract

  A GFP fusion to the N-terminal 238 amino acids of the mammalian lamin B receptor (LBR) localises to the nuclear envelope (NE) when expressed in Nicotiana tabacum plants, showing properties expected of a native plant NE protein. In this study, we have used this chimaeric construct to explore evidence for common mechanisms of NE targeting and retention between plants and animals, given there is no plant homologue of the mammalian LBR or of one of its binding partners, lamin B. Binding mutants of LBR-GFP were created and fluorescence recovery after photobleaching of mutant and wild type constructs employed to examine their retention in the plant NE. Unmutated LBR-GFP was significantly less mobile in the NE than the lamin binding domain deletion mutant, which was also localised to theER and punctate structures in some cells. Mutation of the chromatin binding domain resulted in localisation of the protein in nuclear inclusions, in which it was immobile. Our findings, that expression of truncated LBR-GFP in plant cells results in altered targeting and retention relative to wt LBR-GFP, suggest that plant cells can recognize the INM-targeting motif of LBR. Altered mobility of the truncated probe indicates that not only do plant cells recognize this signal, but also have nuclear proteins that interact weakly with LBR.

  Website 
• Graumann K, Evans DE, Irons S, Runions J, 'Dynamics of the lamin B receptor in the plant nuclear envelope'
  Comparative Biochemistry and Physiology - Part A: Molecular & Integrative Physiology 146 (4, Supplement) (2007) pp.S193-S193
  ISSN: 1095-6433
  Abstract

  The nuclear envelope (NE) is a double membrane system consisting of the inner nuclear envelope (INE), the outer nuclear envelope (ONE) and nuclear pore complexes (NPCs). Most of our knowledge about the NE proteome comes from studies in animal systems. Recent investigations in plant systems have shown that plants do not have homologues for the majority of animal NE proteins. In a previous study in our laboratory, a construct consisting of the N-terminus of the human lamin B receptor (LBR) fused to GFP was shown to target the plant INE. In mammalian cells, LBR is an intrinsic INE protein, whose targeting to the INE is facilitated by a nuclear localization signal and retention in the INE is achieved by LBR binding mainly to chromatin and lamins. In this study the targeting and retention of LBR–GFP in the plant NE has been investigated by introducing mutations in key domains of LBR and employing fluorescence recovery after photobleaching experiments. Mutation of the chromatin binding domain caused LBR to accumulate in nuclear inclusions in which it was immobile. Deletion of the lamin binding domain resulted in the construct being localized not only to the NE but also ER and to be significantly more mobile then the wild type LBR–GFP in the NE. In the case of both the lamin binding deletion and wild type LBR–GFP, mobility was found to be much greater than previously described in mammalian cells. (Abstracts of the Annual Main Meeting of the Society for Experimental Biology, Glasgow, Scotland, 31st March - 4th April, 2007)

  Website 
• Graunnann K, Irons SL, Runions J, Evans DE, 'Retention and Mobility of the Mammalian Lamin B Receptor in the Plant Nuclear Envelope'
  Biology of the Cell 99 (10) (2007) pp.553-562
  ISSN: 0248-4900 eISSN: 1768-322X
  Abstract

  Background information. In a previous study, we showed that GFP (green fluorescent protein) fused to the N-terminal 238 amino acids of the mammalian LBR (lamin B receptor) localized to the NE (nuclear envelope) when expressed in the plant Nicotiana tabacum. The protein was located in the NE during interphase and migrated with nuclear membranes during cell division. Targeting and retention of inner NE proteins requires several mechanisms: signals that direct movement through the nuclear pore complex, presence of a transmembrane domain or domains and retention by interaction with nuclear or nuclear-membrane constituents.

  Website 
• Ryder M, Gerard F, Evans DE, Hodson MJ, 'The use of root growth and modelling data to investigate amelioration of aluminium toxicity by silicon in Picea abies seedlings'
  JOURNAL OF INORGANIC BIOCHEMISTRY 97 (2003) pp.52-58
  ISSN: 0162-0134
  Abstract

  Three-week-old Picea abies seedlings were grown for 7 days in 100 muM aluminium (AI), combined with 1000 or 2000 muM silicon (Si). Solution pH was adjusted to 4,00, 4.25, 4.50, 4.75, or 5.00. In the absence of Si, solution pH had no effect on the decrease in root growth caused by 100 muM Al. Silicon did not ameliorate toxic effects of Al on root growth at pH 4.00, 4.25 and 4.50, whereas significant, and apparently complete, amelioration was found at pH 4.75 and 5.00. An equilibrium speciation model (EQ3NR), with a current thermodynamic database, was used to predict the behaviour of Al and Si in growth solutions. When Si was not present in the 100 muM Al solutions, Al3+ declined from 92.4% of total Al at pH 4.00 to 54.6% at pH 5.00, and there was a concomitant increase in hydroxyaluminium species as pH increased. The addition of 1000 muM Si to the 100 muM At solutions caused a reduction in Al3+ content over the whole pH range: at pH 4.00 Al3+ fell from 92.4 to 83.3% in the presence of Si; and at pH 5.00 the fall was from 54.6 to 17.7%. These falls were attributed to the formation of hydroxyaluminosilicate (HAS) species. Similar, but somewhat greater, changes were observed in solutions containing 2000 muM Si. The match between root growth observations and the modelling data was not very good. Modelling predicted that change in Al3+ content with pH in the presence of Si was gradual, but root growth was markedly increased between pH 4.50 and 4.75. Differences between root growth and modelling data may be due to the model not correctly predicting solution chemistry or to in planta. effects which override the influence of solution chemistry. (C) 2003 Elsevier Inc. All rights reserved.

  Website 
• Irons SL, Evans DE, Brandizzi F, 'The First 238 Amino Acids of the Human Lamin B Receptor Are Targeted to the Nuclear Envelope in Plants'
  Journal of Experimental Botany 54 (2003) pp.943-950
  ISSN: 0022-0957 eISSN: 1460-2431
  Abstract In plants, the nuclear envelope (NE) is one of the least characterized cellular structures. In particular, little is known about its dynamics during the cell cycle. This is due to the absence of specific markers for in vivostudies. To generate such an in vivo marker, the suitability of the human lamin B receptor (LBR) was tested. When the first 238 amino acids of the LBR, fused to the green fluorescent protein (GFP), were expressed in tobacco plants, fluorescence accumulated only at the NE of leaf epidermal cells. This was confirmed by electron microscopy. The protein was shown to be membrane‐integral by phase separation. Distribution of fluorescence was compared with two ER markers, GFP‐calnexin and GFP‐HDEL. While co‐localization of all three markers was noted at the NE, only LBR‐GFP was specific to the NE, while the other two also showed fluorescence of the cortical ER. These results suggest that common targeting mechanisms to those in animals and fungi exist in plants to direct and locate proteins to the NE. This chimaeric construct is the first available fluorescent integral membrane protein marker to be targeted exclusively to the plant NE and it provides a novel opportunity to investigate the dynamics of this membrane system in vivo. With it, the cell cycle was followed in tobacco BY‐2 cells stably expressing the fusion protein. The interphase labelling of the NE altered in metaphase into an ER‐like meshwork, suggesting the dispersal of the NE to ER as in animal cells. Finally, the meshwork of fluorescent membranes was lost and new fluorescent NE formed around the daughter nuclei.Website 
• Brandizzi F, Hanton S, daSilva LLP, Boevink P, Evans D, Oparka K, Denecke J, Hawes C, 'Er Quality Control Can Lead to Retrograde Transport From the Er Lumen to the Cytosol and the Nucleoplasm in Plants'
  Plant Journal 34 (2003) pp.269-281
  ISSN: 0960-7412 eISSN: 1365-313X
  Abstract

  Quality control in the secretory pathway is a fundamental step in preventing deleterious effects that may arise by the release of malfolded proteins into the cell or apoplast. Our aims were to visualise and analyse the disposal route followed by aberrant proteins within a plant cell in vivo using fluorescent protein technology. A green fluorescent protein (GFP) fusion was detected in the cytosol and the nucleoplasm in spite of the presence of an N-terminal secretory signal peptide. In contrast to secreted GFP, the fusion protein was retained in the cells where it was degraded slowly, albeit at a rate much higher than that of the endoplasmic reticulum (ER)-retained derivative GFP-HDEL. The fusion protein could not be stabilised by inhibitors of transport or the cytosolic proteasome. However, the protein is a strong lumenal binding protein (BiP) ligand. Complete signal peptide processing even after long-term expression in virus-infected leaves rules out the possibility that the documented accumulation in the cytosol and nucleoplasm is because of the bypassing of the translocation pores. The data are consistent with the hypothesis that the fusion protein is disposed off from the ER via a retrograde translocation back to the cytosol. Moreover, accumulation in the nucleoplasm was shown to be microtubule dependent unlike the well-documented diffusion of cytosolically expressed GFP into the nucleoplasm. The apparent active transport of the GFP fusion into the nucleoplasm may indicate an as yet undiscovered feature of the ER-associated degradation (ERAD) pathway and explain the insensitivity to degradation by proteasome inhibitors.

  Website 
• Gunawardena AHLAN, Pearce DME, Jackson MB, Hawes CR, Evans DE, 'Rapid changes in cell wall pectic polysaccharides are closely associated with early stages of aerenchyma formation, a spatially localized form of programmed cell death in roots of maize (Zea mays L.) promoted by ethylene'
  PLANT CELL AND ENVIRONMENT 24 (2001) pp.1369-1375
  ISSN: 0140-7791
  Abstract Aerenchyma formation in roots of maize (Zea mays L.) involves programmed death of cortical cells that is promoted by exogenous ethylene (1 muL L-1) or by endogenous ethylene produced in response to external oxygen shortage (3%, v/v). In this study, evidence that degeneration of the cell wall accompanies apoptotic-like changes previously observed in the cytoplasm and nucleus (Gunawardena et al. Planta 212, 205-214, 2001), has been sought by examining de-esterified pectins (revealed by monoclonal antibody JIM 5), and esterified pectins (revealed toy monoclonal antibody JIM 7). In controls, de-esterified wall pectins were found at the vertices of triangular junctions between cortical cells (untreated roots). Esterified pectins in control roots were present in the three walls bounding triangular cell-to-cell junctions. After treatment with 3% oxygen or 1 muL L-1 ethylene, this pattern was lost, but walls surrounding aerenchyma gas spaces became strongly stained. The results showed that cell wall changes commenced within 0.5 d and evidently were initiated by ethylene in parallel with cytoplasmic and nucleoplasmic events associated with classic intracellular processes of programmed cell death.
• Gunawardena AHLAN, Pearce, DME, Jackson MB, Hawes CR, Evans, DE, 'Rapid Changes In Cell Wall Pectic Polysaccharides Are Closely Associated With Early Changes Of Aerenchyma Formation, A Spatialy Localized Form Of Programmed Cell Death In Roots Of Maize (Zea mays L.) Promoted By Ethylene'
  Plant, Cell and Environment 24 (2001) pp.1369-1375
  ISSN: 0140-7791
  Abstract

  Aerenchyma formation in roots of maize (Zea mays L.) involves programmed death of cortical cells that is promoted by exogenous ethylene (1 µL L⁻¹) or by endogenous ethylene produced in response to external oxygen shortage (3%, v/v). In this study, evidence that degeneration of the cell wall accompanies apoptotic-like changes previously observed in the cytoplasm and nucleus (Gunawardena et al. Planta 212, 205–214, 2001), has been sought by examining de-esterified pectins (revealed by monoclonal antibody JIM 5), and esterified pectins (revealed by monoclonal antibody JIM 7). In controls, de-esterified wall pectins were found at the vertices of triangular junctions between cortical cells (untreated roots). Esterified pectins in control roots were present in the three walls bounding triangular cell-to-cell junctions. After treatment with 3% oxygen or 1 µL L⁻¹ ethylene, this pattern was lost but walls surrounding aerenchyma gas spaces became strongly stained. The results showed that cell wall changes commenced within 0·5 d and evidently were initiated by ethylene in parallel with cytoplasmic and nucleoplasmic events associated with classic intracellular processes of programmed cell death.

  Website 
• Andreeva AV, Zheng H, Saint-Jore CM, Kutuzov MA, Evans DE Hawes CR, 'Organisation of Transport from endoplasmic reticulum to Golgi in Higher Plants'
  Biochemical Society Transactions 28 (2000) pp.505-512
  ISSN: 0300-5127 eISSN: 1470-8752
  Abstract

  In plant cells, the organization of the Golgi apparatus and its interrelationships with the endoplasmic reticulum differ from those in mammalian and yeast cells. Endoplasmic reticulum and Golgi apparatus can now be visualized in plant cells in vivo with green fluorescent protein (GFP) specifically directed to these compartments. This makes it possible to study the dynamics of the membrane transport between these two organelles in the living cells. The GFP approach, in conjunction with a considerable volume of data about proteins participating in the transport between endoplasmic reticulum and Golgi in yeast and mammalian cells and the identification of their putative plant homologues, should allow the establishment of an experimental model in which to test the involvement of the candidate proteins in plants. As a first step towards the development of such a system, we are using Sar1, a small G-protein necessary for vesicle budding from the endoplasmic reticulum. This work has demonstrated that the introduction of Sar1 mutants blocks the transport from endoplasmic reticulum to Golgi in vivo in tobacco leaf epidermal cells and has therefore confirmed the feasibility of this approach to test the function of other proteins that are presumably involved in this step of endo-membrane trafficking in plant cells.

  Website 
• Gunawaradena AHLAN, Pearce DM, Jackson MB, Hawes CR Evans DE, 'Characterisation Of Programmed Cell Death During Aerenchyma Formation Induced By Ethylene Or Hypoxia In Roots Of Maize (Zea mays L.).'
  Planta 212 (2000) pp.205-214
  ISSN: 0032-0935
  Abstract

  Aerenchyma is a tissue type characterised by prominent intercellular spaces which enhance flooding tolerance in some plant species by facilitating gas diffusion between roots and the aerial environment. Aerenchyma in maize roots forms by collapse and death of some of the cortical cells in a process that can be promoted by imposing oxygen shortage or by ethylene treatment. Maize roots grown hydroponically in 3% oxygen, 1 μl l−1 ethylene or 21% oxygen (control) were analysed by a combination of light and electron microscopy. Use of in-situ terminal deoxynucleotidyl transferase-mediated dUTP nick-end labelling (TUNEL) suggested internucleosomal cleavage of DNA. However, chromatin condensation detectable by electron microscopy was preceded by cytoplasmic changes including plasma membrane invagination and the formation of vesicles, in contrast to mammalian apoptosis in which chromatin condensation is the first detectable event. Later, cellular condensation, condensation of chromatin and the presence of intact organelles surrounded by membrane resembling apoptotic bodies were observed. All these events were complete before cell wall degradation was apparent. Therefore, aerenchyma formation initiated by hypoxia or ethylene appears to be a form of programmed cell death that shows characteristics in part resembling both apoptosis and cytoplasmic cell death in animal cells.

  Website 
• Cocker KM, Evans DE, Hodson MJ, 'The amelioration of aluminium toxicity by silicon in higher plants: Solution chemistry or an in planta mechanism?'
  PHYSIOLOGIA PLANTARUM 104 (1998) pp.608-614
  ISSN: 0031-9317 eISSN: 1399-3054
  Abstract

  Aluminium (Al) toxicity is a very important Factor limiting the growth of plants on acidic soils. Recently, a number of workers have shown that. under certain conditions, silicon (Si) can ameliorate the toxic effects of Al in hydroponic culture. The mechanism of the amelioration is unclear, but three suggestions have been put forward. Si-induced increase in solution pH during the preparation of hydroponic solutions. reduced availability of Al due to the formation of hydroxyaluminosilicate (HAS) species in those solutions during plant growth; or in planta detoxification. It is now known that it is possible to make up Al and Si solutions in an order in which pH is lowered prior to Al addition; in these cases amelioration has still been observed. Amelioration has also been noted in experiments where HAS formation is minimal. These observations would suggest that, at least under some circumstances, there is an in planta component to the amelioration phenomenon. Several microanalytical investigations have noted codeposition of Al and Si in root cell walls. We propose a model in which root cell walls are the main internal sites of aluminosilicate (AS) and/or HAS formation and of Al detoxification. Factors promoting AS/HAS formation in this compartment include: high apoplastic pH; the presence of organic substances (e.g. malate); and the presence of suitable local concentrations of reactive forms of Al and Si, on or within the surfaces of the wall matrix. All these are likely to be important in the amelioration of Al toxicity.

• Andreeva AV, Kutuzov MA, Evans DE, Hawes CR, 'The structure and function of the Golgi apparatus: a hundred years of questions'
  JOURNAL OF EXPERIMENTAL BOTANY 49 (325) (1998) pp.1281-1291
  ISSN: 0022-0957 eISSN: 1460-2431
  Abstract Over the last century, the Golgi apparatus has attracted the attention of researchers world-wide. This highly variable and polymorphic organelle plays a central role in intracellular membrane traffic. Not only does it receive all the secretory material and membrane synthesized by the endoplasmic reticulum and modifies these products by glycosylation, but also packages them and sends them in vesicular carriers to their correct destinations. It is also capable of the synthesis of complex polysaccharides used for building cell walls, a feature unique for higher plants. Yet, the current models of Golgi function are based on those established for yeast and mammalian cells and may not be completely relevant to plants. This review is an attempt to summarize the current knowledge of the plant Golgi apparatus and, where possible, to discuss the applicability of the current models of Golgi function to the plant cell.Website 
• Cocker KM, Evans DE, Hodson MJ, 'The amelioration of aluminium toxicity by silicon in wheat (Triticum aestivum L.): malate exudation as evidence for an in planta mechanism'
  PLANTA 204 (1998) pp.318-323
  ISSN: 0032-0935
  Abstract

  Two wheat (Triticum aestivum L.) cultivars, one aluminium tolerant (Atlas 66) and one sensitive (Scout 66), were grown in a continuous-flow culture system (less than or equal to pH 5.0) containing aluminium (0-100 mu M) and silicon (0-2000 mu M) in factorial combination. Treatment with silicon resulted in a highly significant amelioration of aluminium toxicity as assessed by root growth in both cultivars. Amelioration was influenced by wheat cultivar and silicon concentration, as 2000 mu M silicon significantly ameliorated the toxic effects of 100 mu M aluminium in Atlas 66, and only 5 mu M silicon alleviated the effect of 1.5 mu M aluminium on Scout 66. Nutrient medium pH was critical, as an amelioration by silicon was apparent only at pH > 4.2 for Atlas 66, and at pH > 4.6 for Scout 66. Silicon neither reduced levels of toxic aluminium species in the growth solutions, nor the amount of aluminium taken up by roots. In experiments to assess exudation of malate by Atlas 66 roots treated with 100 mu M aluminium, the presence of 2000 mu M silicon (pH 4.6) was found to have a negligible effect on exudation. In contrast, citrate, a known aluminium chelator, reduced aluminium-induced exudation of malate at 5-40 mu M and completely inhibited it at 100 mu M citrate. The results indicate that silicon does not reduce aluminium phytotoxicity as a result of aluminium/silicon interactions in the external media, and that the mechanism of amelioration has an in planta component.

• Cocker KM, Hodson MJ, Evans DE, Sangster AG, 'Interaction between silicon and aluminum in Triticum aestivum L. (cv. Celtic)'
  ISRAEL JOURNAL OF PLANT SCIENCES 45 (1997) pp.285-292
  ISSN: 0792-9978
  Abstract

  Three treatments were selected for a microanalytical investigation of the basal third of the root, and the zone 3.5 mm behind the root tip: 2800 mu mol L-1 Si; 75 mu mol L-1 Al; and a combination of the two. When plants were grown in 2800 mu mol L-1 Si the major silica deposition sites in the roots were the endodermal walls. In the 75 mu mol L-1 Al treatment, Al was mainly located in the epidermal and hypodermal walls. Al treatment caused a leakage of phosphorus into these cell walls. When both 2800 mu mol L-1 Si and 75 mu mol L-1 Al were present in the nutrient solution, only Si was deposited in the endodermal walls, while both elements were present in the epidermal walls. Leakage of phosphorus appeared to be prevented in the presence of Si.

• HAMMOND KE, EVANS DE, HODSON MJ, 'ALUMINIUM SILICON INTERACTIONS IN BARLEY (HORDEUM-VULGARE L) SEEDLINGS'
  PLANT AND SOIL 173 (1995) pp.89-95
  ISSN: 0032-079X eISSN: 1573-5036
  Abstract

  The response of seedlings of the monocot Hordeum vulgare L. cv. Bronze to 0,25 and 50 mu M aluminium in factorial combination with 0, 1.4, 2.0 and 2.8 mM Si was tested in hydroponic culture at pH 4.5. Nutrient solution (500 mu M calcium nitrate) and Al/Si treatments were designed to avoid the precipitation of Al from solution. Silicon treatments gave significant amelioration of the toxic effects of Al on root and shoot growth and restored calcium levels in roots and shoots at harvest to levels approaching those of control plants. Aluminium uptake by roots was also significantly diminished in the presence of Si. Silicon alone gave a slight stimulation of growth, insufficient to explain its ameliorative effect on Al toxicity. The mechanism of the Si effect on Al toxicity in monocotyledons awaits further investigation.

• HODSON MJ, EVANS DE, 'ALUMINUM-SILICON INTERACTIONS IN HIGHER-PLANTS'
  JOURNAL OF EXPERIMENTAL BOTANY 46 (1995) pp.161-171
  ISSN: 0022-0957
  Abstract

  Aluminium and silicon are usually abundant in soil mineral matter, but their availability for plant uptake is limited by low solubility and, in the case of Al, high soil pH causes precipitation of the element: in insoluble forms. Al toxicity is a major problem in naturally occurring acid soils and in soils affected by acidic precipitation. Al has no known role in higher plants, and is generally known as a toxic element, whereas Si is generally regarded as a beneficial element. Recently, it has been suggested that Al toxicity can be ameliorated by Si in a variety of animal systems. In this review the evidence that amelioration of Al toxicity by Si can also occur in plants is assessed. At present such amelioration has been shown in sorghum, barley, teosinte, and soybean, but not in rice, wheat, cotton, and pea. Plant species vary considerably in the amounts of Al and Si that they transport into their tissues, and it seems that very high Si accumulation and very high Al accumulation are mutually exclusive. The mechanisms considered for amelioration are: solution effects; codeposition of Al and Si within the plant; effects in the cytoplasm and on enzyme activity; and indirect effects.

• HORSLEY D, COLEMAN J, EVANS D, CROOKS K, PEART J, SATIATJEUNEMAITRE B, HAWES C, 'A Monoclonal-antibody, Jim-84, Recognizes the Golgi-apparatus and Plasma-membrane in Plant-cells'
  Journal of Experimental Botany 44 (1993) pp.223-229
  ISSN: 0022-0957 eISSN: 1460-2431
  
• Dewey M, Evans D, Coleman J, Priestley R, Hull R, Horsley D, Hawes C, 'Antibodies in Plant-science'
  Acta Botanica Neerlandica 40 (1) (1991) pp.1-27
  ISSN: 0044-5983
  Website 
• EVANS DE, SMITH AR, TAYLOR JE, HALL MA, 'ETHYLENE METABOLISM IN PISUM-SATIVUM-L - KINETIC-PARAMETERS, THE EFFECTS OF PROPYLENE, SILVER AND CARBON-DIOXIDE AND COMPARISON WITH OTHER SYSTEMS'
  PLANT GROWTH REGULATION 2 (1984) pp.187-195
  ISSN: 0167-6903
  

Book chapters

• Poulet A, Zhou X, Tamura K, Meier I, Tatout C, Graumann K, Evans DE, 'Computational Methods for Studying the Plant Nucleus' in Gundersen GG, Worman HJ (ed.), The LINC Complex (Methods in Molecular Biology, Vol. 1840), Springer (2018)
  ISBN: 9781493986903 eISBN: 9781493986910
  Abstract

  The analysis of nuclear envelope components and their function has recently been progressed by the use of computational methods of analysis. The methods in this chapter provided by members of the International Plant Nucleus Consortium address the identification of novel nuclear envelope proteins and the study of structure and mobility of the nucleus. DORY2 is an upgrade of the KASH-finder DORY, and NucleusJ is used to characterize the three-dimensional structure of the nucleus in light microscope images. Finally, a method is provided for analysis of the migration of the nucleus, a key technique for exploring the function of plant nuclear proteins.
  

  Website 

Conference papers

• Graumann K, Irons S, Runions J, Evans D, 'SUN domain proteins at the plant nuclear envelope'
  150 (3 (Supplement)) (2008) pp.S202-S202
  ISSN: 1095-6433
  Abstract

  The nuclear envelope (NE) is a double membrane system that forms a protective barrier around chromatin and organises intranuclear structures and activities. The outer nuclear membrane (ONM) is continuous with the ER and associates with cytoskeletal elements. The inner nuclear membrane (INM) interacts with chromatin and the nucleoskeleton and plays a fundamental role in orchestrating nuclear functions such as nucleic acid metabolism. Most of our knowledge of the NE proteome and its functions comes from studies in animal systems. Despite its importance, the plant NE remains poorly understood. Here we present the characterisation of two novel NE proteins, AtSUN1 and AtSUN2, plant homologues of a group of animal and yeast INM proteins containing a well conserved SUN (Sad1/UNC84 homology) domain important for nucleo-cytoskeletal linkage. Both proteins share a similar domain layout to their animal counterparts and appear to interact with each other as indicated by fluorescence resonance energy transfer. Confocal microscopy of fluorescent protein fusions and electron microscopy suggest localisation to the plant INM. Deletion of either the SUN domain or a nuclear localisation signal abolishes this localisation. These SUN domain proteins are the first true inner nuclear envelope proteins to be identified in plants and provide the first evidence for a plant Linker of Cytoskeleton and Nucleoskeleton Complex.

  Website 

Other publications

• Cocker KM, Evans DE, Hodson MJ, 'Silica amelioration of aluminum-induced effects on root length and cation exchange capacity of wheat grown in hydroponic culture'
  PLANT PHYSIOLOGY 111 (1996) pp.131-131ISSN: 0032-0889
  

Areas of expertise

• Plant cell and molecular biology
• Plant cell and tissue culture
• Plant nuclear architecture and regulation
• Plant biotechnology

Membership of professional bodies

Cell Section leader, Society for Experimental Biology

Conferences

Mitosis and Nuclear Structure, 2013. Company of Biologists Wiston House Conference.

International Plant Nucleus Consortium annual meeting, Olamouc, Czech Republic 2015

Society for Experimental Biology 'Nuclear Dynamics' conference co-organiser, Brighton, 2016

Society for Experimental Biology Annual Main Meeting, Nuclear Dynamics Special Interest Group, Firenze 2018

Indepth Kick-Off meeting, Clermont Ferrand, France, 2018

Indepth Management Meeting and Conference, Praha, 2019

SEB Annual Main Meeting and Special Interest Group session, Online 2021

Other experience

1983-1988 Botany Fellow Department of Plant Sciences, University of Oxford (Junior research fellow, Wolfson College, Oxford, 1984-1988)

1988-1998 Royal Society University Research Fellow (Research Fellow, Wolfson College, Oxford, 1989-1992)

1989-1990       Stipendiary Lecturer, Magdalen College Oxford (1 year temporary post)

Honorary Secretary of the Cell Biology Section of the Society for Experimental Biology (2003- 2008)

Further information