University of Southampton Archives

GARNet Research Roundup: December 23rd 2019

Categories: Durham University, Global, John Innes Centre, Uncategorized, University of Birmingham, University of Cambridge, University of Glasgow, University of Leeds, University of Southampton, University of York

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Published on: December 23, 2019

The final GARNet Research Roundup of 2019 begins with three studies from the John Innes Centre. Firstly Steve Penfield’s group conducts a field-experiment that monitors FLC levels in winter oilseed rape. Second is a study from the Zilberman lab looking at the relationship between Histone H1 and DNA methylation.

Third is work from the Yant lab in JIC/Nottingham that investigates adaptive gene flow between Arabidopsis arenosa and Arabidopsis lyrata.

The next two papers are led from the Etchells lab in Durham, the first has developed a vascular-localised transcriptional network and the second is a methods paper for image analysis.

The sixth paper includes co-authors from Southampton and investigates nuclear-chloroplast signaling in Arabidopsis mediated by the GUN1 protein.

The next two papers include members of the current GARNet advisory committee. Yoselin Benitez-Alfonso from the University of Leeds is an author on a paper that models plasmodesma geometry whilst members of the Kaiserli lab in Glasgow are involved in a study that investigates the factors involved in auxin-dependent thermomorphogenesis.

The Dupree lab in Cambridge leads the next research paper that looks at the detailed composition of the cell wall in the softwood Spruce.

The next two papers are from the Sainsbury lab, Norwich. Firstly the Kamoun lab looks at the molecular code of a plant NLR immune receptors whilst in the second paper members of the Zipfel lab are co-authors on a study that looks at defence-related protease activity from a fungal pathogen of strawberry.

The twelfth paper is from Ian Graham’s lab at the University of York and looks at the role of light signaling during seed development.

Sue Armstrong from Birmingham is a co-author on the next paper in which researchers present a genetic map of the field cress Lepidium campestre.

The final two papers include researchers from Royal Holloway University of London and look at the role of different transcription factors during embryo or root meristem development.

O’Neill CM, Lu X, Calderwood A, Tudor EH, Robinson P, Wells R, Morris R, Penfield S (2019) Vernalization and Floral Transition in Autumn Drive Winter Annual Life History in Oilseed Rape. Curr Biol. doi: 10.1016/j.cub.2019.10.051
Open Access

Carmel O’Neill is first author on the research from the Morris and Penfield labs at the John Innes Centre. This paper describes experiments that monitored FLC levels in field-growth winter oilseed rape. Surprisingly they shows that decline of FLC during October in relatively mild-temperatures of 10-15C reduce FLC levels, leading to floral transition prior to the colder winter temperatures. This work shows the importance of field experiments to understand real-world mechanisms that control crop development.

https://www.cell.com/current-biology/fulltext/S0960-9822(19)31391-0

Choi J, Lyons DB, Kim MY, Moore JD, Zilberman D (2019) DNA Methylation and Histone H1 Jointly Repress Transposable Elements and Aberrant Intragenic Transcripts. Mol Cell. doi: 10.1016/j.molcel.2019.10.011
This research from the Zilberman lab at the John Innes Centre is led by Jaemyoung Choi and looks at the relationship between histone H1 and the DNA methylation machinery during the maintenance of transcriptional homeostasis.

https://www.sciencedirect.com/science/article/abs/pii/S1097276519307890?via%3Dihub

Marburger S, Monnahan P, Seear PJ, Martin SH, Koch J, Paajanen P, Bohutínská M, Higgins JD, Schmickl R, Yant L (2019) Interspecific introgression mediates adaptation to whole genome duplication. Nat Commun. doi: 10.1038/s41467-019-13159-5
Open Access

Sarah Marburger from Levi Yant’s lab at the John Innes Centre/University of Nottingham leads this research that includes co-authors from Leicester, Edinburgh and the Czech Republic. They look at the effect of whole-genome duplication on gene flow between Arabidopsis arenosa and Arabidopsis lyrata.

Smit M, McGregor S, Sun H, Gough C, Bågman AM, Soyars CL, Kroon JTM, Gaudinier A, Williams CJ, Yang X, Nimchuk ZL, Weijers D, Turner SR, Brady SM, Etchells P (2019) A PXY-Mediated Transcriptional Network Integrates Signaling Mechanisms to Control Vascular Development in Arabidopsis. Plant Cell. doi: 10.1105/tpc.19.00562
Open Access

This large-scale systems-biology paper is a UK-US-China-Dutch collaboration led by Margot Smit at Wageningen, Shauni McGregor and Peter Etchells at Durham University. They have developed a detailed transcriptional network based on the vascular-localised PHLOEM INTERCALATED WITH XYLEM (PXY) receptor kinase.

http://www.plantcell.org/content/early/2019/12/05/tpc.19.00562.long

Bagdassarian KS, Connor KA, Jermyn IH, Etchells JP (2019) Versatile method for quantifying and analyzing morphological differences in experimentally obtained images. Plant Signal Behav. doi: 10.1080/15592324.2019.1693092
This paper from Peter Etchells lab in Durham is led by Kristine Bagdassarian and introduces a bespoke method for inspecting the differences between the morphologies of several plant mutants at the cellular level.

Shimizu T, Kacprzak SM, Mochizuki N, Nagatani A, Watanabe S, Shimada T, Tanaka K, Hayashi Y, Arai M, Leister D, Okamoto H, Terry MJ, Masuda T (2019) The retrograde signaling protein GUN1 regulates tetrapyrrole biosynthesis. Proc Natl Acad Sci U S A. doi: 10.1073/pnas.1911251116

Open Access

Sylwia M. Kacprzak and Matthew Terry from the University of Southampton are co-authors on this Japanese-led study that looks at the interaction between nuclear and chloroplast genomes as controlled by role that the GUN1 protein plays in control of tetrapyrrole metabolism.

Deinum EE, Mulder BM, Benitez-Alfonso Y (2019) From plasmodesma geometry to effective symplasmic permeability through biophysical modelling. Elife. doi: 10.7554/eLife.49000
Open Access

Eva Deinum is lead author of this study that includes GARNet Committee member Yoselin Benitez-Alfonso as co-author. They have applied biophysical modeling to calculate effective symplasmic permeability for the transport of molecules through plasmodesmata. The resulting open-source model has been refined through experimental observations.

Dr Deinum will be leading a GARNet-supported workshop on this multilevel model during the July 2020 EMBO workshop on ‘Intercellular communication and plasmodesmata in plant development and disease’.

van der Woude LC, Perrella G, Snoek BL, van Hoogdalem M, Novák O, van Verk MC, van Kooten HN, Zorn LE, Tonckens R, Dongus JA, Praat M, Stouten EA, Proveniers MCG, Vellutini E, Patitaki E, Shapulatov U, Kohlen W, Balasubramanian S, Ljung K, van der Krol AR, Smeekens S, Kaiserli E, van Zanten M (2019) HISTONE DEACETYLASE 9 stimulates auxin-dependent thermomorphogenesis in Arabidopsis thaliana by mediating H2A.Z depletion. Proc Natl Acad Sci U S A. doi: 10.1073/pnas.1911694116

This wide collaboration is led by Lennard van der Woude at Utrecht University and includes Giorgio Perrella and Eirini Kaiserli from Glasgow as co-authors. This research looks at the complex relationship between thermomorphogenesis, auxin and light signaling, histone deacylation and the regulation of histone variant H2A.Z.

Terrett OM, Lyczakowski JJ, Yu L, Iuga D, Franks WT, Brown SP, Dupree R, Dupree P (2019) Molecular architecture of softwood revealed by solid-state NMR. Nat Commun. doi: 10.1038/s41467-019-12979-9

Open Access

This research from the Dupree lab in Cambridge is led by Olivier Terrett and uses solid-state NMR to analyse the cell wall composition of the softwood spruce, in part through comparison with Arabidopsis cell walls. This information is an essential requirement to build experimental strategies for the biorefining of particular wood-types.

Adachi H, Contreras M, Harant A, Wu CH, Derevnina L, Sakai T, Duggan C, Moratto E, Bozkurt TO, Maqbool A, Win J, Kamoun S (2019) An N-terminal motif in NLR immune receptors is functionally conserved across distantly related plant species. Elife. doi: 10.7554/eLife.49956

Open Access

Hiroaki Adachi leads this study from lab of Sophien Kamoun at the Sainsbury lab, Norwich. In this research they interrogate the molecular code of a plant NLR immune receptor to identify the minimal functional motifs that are required to induce hypersensitive cell death in response to a plant pathogen.

https://elifesciences.org/articles/49956

Caro MDP, Holton N, Conti G, Venturuzzi AL, Martínez-Zamora MG, Zipfel C, Asurmendi S, Díaz-Ricci JC (2019) The fungal subtilase AsES elicits a PTI-like defence response in Arabidopsis thaliana plants independently of its enzymatic activity. Mol Plant Pathol. doi: 10.1111/mpp.12881
Open Access

Nicolas Holton and Cyril Zipfel from the Sainsbury Lab in Norwich are co-authors on this Argentinian-led study with María del Pilar Caro as both first and corresponding author. They characterize the proteolytic role of the elicitor subtilisin (AsES) from strawberry fungal pathogen Acremonium strictum during an immune response.

Barros-Galvão T, Dave A, Gilday AD, Harvey D, Vaistij FE, Graham IA (2019) ABA INSENSITIVE4 promotes rather than represses PHYA-dependent seed germination in Arabidopsis thaliana. New Phytol. doi: 10.1111/nph.16363
Open Access

Thiago Barros-Galvão and Ian Graham at the University of Leeds lead this research that investigates the role of phytochrome A (PHYA) and PHYB signaling during seed development in Arabidopsis.

https://nph.onlinelibrary.wiley.com/doi/abs/10.1111/nph.16363

Desta ZA, Kolano B, Shamim Z, Armstrong SJ, Rewers M, Sliwinska E, Kushwaha SK, Parkin IAP, Ortiz R, de Koning DJ (2019) Field cress genome mapping: Integrating linkage and comparative maps with cytogenetic analysis for rDNA carrying chromosomes. Sci Rep. doi: 10.1038/s41598-019-53320-0

Open Access

This Swedish led study has Zeratsion Abera Desta as lead author and includes Sue Armstrong from the University of Birmingham as a co-author. They have produced an early genome map of field cress (Lepidium campestre), which is a potential oilseed plant. They show that diploid Lepidium campestre has 16 chromosomes.

Leviczky T, Molnár E, Papdi C, Őszi E, Horváth GV, Vizler C, Nagy V, Pauk J, Bögre L, Magyar Z (2019) E2FA and E2FB transcription factors coordinate cell proliferation with seed maturation. Development. doi: 10.1242/dev.179333
Open Access

Tünde Leviczky is first author on this Hungarian-led study that includes co-authors from Royal Hollaway University of London. This work characterises the role of the E2F transcription factors and the RETINOBLASTOMA-RELATED repressor protein during Arabidopsis embryo development.

https://dev.biologists.org/content/146/22/dev179333.long

Lokdarshi A, Papdi C, Pettko-Szandtner A, Dorokhov S, Scheres B, Magyar Z, von Arnim AG, Bogre L, Horváth B (2019) ErbB-3 BINDING PROTEIN 1 Regulates Translation and Counteracts RETINOBLASTOMA RELATED to Maintain the Root Meristem. Plant Physiol. doi: 10.1104/pp.19.0080
This UK-US-Hungary collaboration includes Ansul Lokdarshi and Csaba Papdi as co-first authors and Laszlo Bogre and Beatrix Horvath from Royal Hollaway University of London as corresponding authors. They assessed the role of the ErbB-3 BINDING PROTEIN 1 transcription factor during Arabidopsis root meristem development

GARNet Research Roundup: July 26th 2019

by Geraint

Categories: Aberystwyth University, Brassica, Cambridge University, Cardiff University, Edinburgh University, Global, John Innes Centre, Nottingham University, Oxford University, Uncategorized, University of Bath, University of Cambridge, University of Edinburgh, University of Nottingham, University of Oxford, University of Sheffield, University of Southampton, University of York

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Published on: July 26, 2019

This summer-time-reading bumper edition of the GARNet Research Roundup begins with two papers from the University of Sheffield that each use advanced imaging techniques. Firstly Andrew Fleming’s group leads a study on the link between stomatal function and mesophyll space morphology. Second is a study from Matthew Johnson’s group that looks at the dynamic arrangement of thylakoid stacks.

Next are two papers that include Alison Smith from the JIC as a corresponding author. The first also includes Vasilios Andriotis from the University of Newcastle and looks at the role of the plastidial pentose phosphate pathway during post-germination growth. Second uses a gene-editing strategy to generate potatoes with altered starch morphologies.

The fifth paper also looks at starch; researchers from Cambridge and Norwich are involved in a study that characterises the role of the LIKE SEX4 1 protein in starch degradation.

The sixth paper is from Aberystwyth University and identifies a transcription factor that alters secondary cell wall composition in Brachypodium and maize. Next is research from the University of Bath that looks at the role of a protein S-acyl transferase during seed germination.

The eighth and ninth papers are led by Spanish research groups and include contributions from UK-based co-authors in Cambridge and Nottingham, working on photoperiod perception or phosphate signaling respectively.

The tenth paper features work from Cardiff University and looks at the role of heterologous expression of the Arabidopsis WEE1 protein. The Bancroft lab from the University of York leads the next paper that investigates glucosinolate signaling in Brassica napus.

The final three manuscripts are methods papers. The first from Edinburgh introduces a new NanoLUC reporter whilst the other two include techniques involved in the investigation of light-regulated growth processes.

Lundgren MR, Mathers A, Baillie AL, Dunn J, Wilson MJ, Hunt L, Pajor R, Fradera-Soler M, Rolfe S, Osborne CP, Sturrock CJ, Gray JE, Mooney SJ, Fleming AJ (2019) Mesophyll porosity is modulated by the presence of functional stomata. Nat Commun. doi: 10.1038/s41467-019-10826-5

Open Access

This UK-wide study is led from Andrew Fleming’s lab in Sheffield and includes Marjorie Lundgren as first author (now working in Lancaster). They use microCT imaging alongside more traditional measurements linked to analysis of gas exchange to show that mesophyll airspace formation is linked to stomatal function in both Arabidopsis and wheat. This allows the authors to propose that coordination of stomata and mesophyll airspace pattern underpins water use efficiency in crops.

https://www.nature.com/articles/s41467-019-10826-5

Wood WH, Barnett SFH, Flannery S, Hunter CN, Johnson MP (2019) Dynamic thylakoid stacking is regulated by LHCII phosphorylation but not its interaction with photosystem I. Plant Physiol. doi: 10.1104/pp.19.00503

Open Access

William Wood is the first author on this study from the University of Sheffield that uses 3D structured illumination microscopy (3D-SIM) to look at the dynamics of thylakoid stacking in both Arabidopsis and spinach. They show that the processes they observe are dependent on light harvesting complex II phosphorylation.

http://www.plantphysiol.org/content/early/2019/06/11/pp.19.00503.long

Andriotis VME, Smith AM (2019) The plastidial pentose phosphate pathway is essential for postglobular embryo development in Arabidopsis. Proc Natl Acad Sci U S A. doi: 10.1073/pnas.1908556116

Open Access

Vasilios Andriotis (now at the University of Newcastle) is the lead author of this work performed in Alison Smith’s lab at the JIC. They look at the role of the plastidial oxidative pentose phosphate pathway (OPPP) during embryo development. This involved demonstrating that production of ribose-5-phosphate (R5P), which in turn leads to synthesis of purine nucleotides, is a critical function of the OPPP.

Tuncel A, Corbin KR, Ahn-Jarvis J, Harris S, Hawkins E, Smedley MA, Harwood W, Warren FJ, Patron NJ, Smith AM (2019) Cas9-mediated mutagenesis of potato starch-branching enzymes generates a range of tuber starch phenotypes. Plant Biotechnol J. doi: 10.1111/pbi.13137

Open Access

Alison Smith and Nicola Patron who work in Norwich Research Park are corresponding authors of this study that includes Aytug Tuncel as first author. They have used Cas9-mediated gene editing to generate potato plants that have a range of different tuber starch structures. This shows that gene-editing techniques allows the transgene-free alteration to generate potentially healthier crops.

Schreier TB, Umhang M, Lee SK, Lue WL, Shen Z, Silver D, Graf A, Müller A, Eicke S, Stadler M, Seung D, Bischof S, Briggs SP, Kötting O, Moorhead GB, Chen J, Zeeman SC (2019) LIKE SEX4 1 acts as a β-amylase-binding scaffold on starch granules during starch degradation. Plant Cell. doi: 10.1105/tpc.19.00089

Open Access

Tina Schreier from the University of Cambridge is the first author on this international study led from Switzerland that also includes Alexander Graf and David Seung from the JIC as co-authors. This study defines a precise role for the LIKE SEX FOUR 1 (LSF1) protein that binds starch and is required for normal starch degradation. Through a variety of experiments they show that the glucan binding, rather than phosphatase activity, is required for LSF1 function during starch degradation.

http://www.plantcell.org/content/early/2019/07/02/tpc.19.00089.long

Bhatia R, Dalton S, Roberts LA, Moron-Garcia OM, Iacono R, Kosik O, Gallagher JA, Bosch M (2019) Modified expression of ZmMYB167 in Brachypodium distachyon and Zea mays leads to increased cell wall lignin and phenolic content. Sci Rep. doi: 10.1038/s41598-019-45225-9

Open Access

Rakesh Bhatia is the first author on this work from the lab of Maurice Bosch at Aberystwyth University. They overexpress the maize MYB transcription factor ZmMYB167 in both Brachypodium and maize. Both species show increased lignin content with Brachypodium but not maize showing a biomass deficit. This indicates that ZmMYB167 could be a useful molecular tool for the alteration of secondary cell wall biosynthesis.

https://www.nature.com/articles/s41598-019-45225-9

Li Y, Xu J, Li G, Wan S, Batistic O, Sun M, Zhang Y, Scott R, Qi B (2019) Protein S-acyl Transferase 15 is Involved in Seed Triacylglycerol Catabolism during Early Seedling Growth in Arabidopsis (2019) J Exp Bot. doi: 10.1093/jxb/erz282

First author on this UK-Chinese collaboration is Yaxiao Li who works with Baoxiu Qi at the University of Bath. The authors characterise the function of Arabidopsis Protein Acyl Transferase 15, AtPAT15. This protein is involved in essential β-oxidation of triacylglycerols during post-germination growth.

Ramos-Sánchez JM, Triozzi PM, Alique D, Geng F, Gao M, Jaeger KE, Wigge PA, Allona I, Perales M (2019) LHY2 Integrates Night-Length Information to Determine Timing of Poplar Photoperiodic Growth. Curr Biol. doi: 10.1016/j.cub.2019.06.003

Open Access

This Spanish-led study includes co-authors from the Sainsbury Laboratory in Cambridge and attempts to define the factors that control photoperiod perception in trees, using poplar as a model system. FLOWERING LOCUS T2 (FT2) has been previously shown to be involved in this process and this study builds on that work to show that night-length information is transmitted by the clock gene LATE ELONGATED HYPOCOTYL 2 (LHY2) and is able to control FT2 expression.

https://www.cell.com/current-biology/fulltext/S0960-9822(19)30696-7?

Silva-Navas J, Conesa CM, Saez A, Navarro-Neila S, Garcia-Mina JM, Zamarreño AM, Baigorri R, Swarup R, Del Pozo JC (2019) Role of cis-zeatin in root responses to phosphate starvation. New Phytol. doi: 10.1111/nph.16020

Ranjan Swarup from the University of Nottingham is a co-author on this Spanish-led study that has Javier Silva-Navas as first author. Through analysis of dark-grown seedlings they have identified a set of new genes involved in root phosphate signaling. In addition they provide evidence of a links between cytokinin and phosphate signaling through modulation of the cell cycle.

Siciliano I, Lentz Grønlund A, Ševčíková H, Spadafora ND, Rafiei G, Francis D, Herbert RJ, Bitonti MB, Rogers HJ, Lipavská H (2019) Expression of Arabidopsis WEE1 in tobacco induces unexpected morphological and developmental changes. Sci Rep. 2019 Jun 18;9(1):8695. doi: 10.1038/s41598-019-45015-3

Open Access

Ilario Siciliano leads this work that includes colleagues from Hilary Rogers’ lab at Cardiff University. The WEE1 protein regulates the cell cycle across eukaryote lineages. In this work they show that overexpression of AtWEE1 in tobacco causes precocious flowering and increased shoot morphogenesis of stem explants whilst in cell culture this WEE1 OX causes smaller cell sizes.

Kittipol V, He Z, Wang L, Doheny-Adams T, Langer S, Bancroft I (2019) Genetic architecture of glucosinolate variation in Brassica napus. J Plant Physiol. doi: 10.1016/j.jplph.2019.06.001

Open Access

This study from the Bancroft lab at the University of York is led by Varanya Kittipol. Through use of Associative Transcriptomics (AT) across a diversity panel of 288 Brassica napus genotypes they are able to identify a set of genes involved in synthesis of glucosinate hydrolysis products.

Urquiza-García U, Millar AJ (2019). Expanding the bioluminescent reporter toolkit for plant science with NanoLUC. Plant Methods. doi: 10.1186/s13007-019-0454-4

Open Access

This study from the University of Edinburgh introduces NanoLUC, a new more stable luciferase-based reporter for use by the plant community.

The final two papers are methods papers that focus on different aspects of light-regulated growth. These are from the University of Southampton and University of York.

https://plantmethods.biomedcentral.com/articles/10.1186/s13007-019-0454-4

Terry MJ, Kacprzak SM (2019) A Simple Method for Quantification of Protochlorophyllide in Etiolated Arabidopsis Seedlings. Methods Mol Biol. doi: 10.1007/978-1-4939-9612-4_14

Oakenfull RJ, Ronald J, Davis SJ (2019) Measuring Phytochrome-Dependent Light Input to the Plant Circadian Clock. Methods Mol Biol. doi: 10.1007/978-1-4939-9612-4_15

GARNet Research Roundup: July 16th

by Geraint

Categories: Aberystwyth University, Durham University, Exeter University, Global, John Innes Centre, New Phytologist, Nottingham University, Oxford Brookes University, Oxford University, Uncategorized, University of Oxford, University of Southampton

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Published on: July 16, 2018

This week’s GARNet research roundup begins with a set of papers looking at aspects of the plant defence response with a focus on the cell wall. Firstly work from Mike Deeks’ lab in Exeter assesses the role of FORMIN4 during pre-invasion cell wall apposition. Secondly Sara Pose and Paul Knox (Leeds) are involved with a study looking at how altered cell wall lignin composition alters the defense response. Finally Joe McKenna and Cyril Zipfel are co-authors on a Norwegian-led study that looks at the influence of plant cell wall integrity maintenance in immune signalling.

Relatedly is a study from the Devoto lab at RHUL looks at the role of the defence hormone methyl jasmonate in Arabidopsis cell culture.

Next are two papers that research different aspects of the plant ER. Verena Kriechbaumer (Oxford Brookes) looks at plant ER-localised Lunapark proteins whilst a study from the University of Warwick provides a preliminary structural analysis of the RTNLB13 reticulon protein.

The seventh and eight papers are involved with the plant response to different growth conditions. Research from University of Nottingham looks at the response of the cortical cell layer of the root meristem to low phosphate conditions whilst work from University of Southampton investigates the relationship between nitrate and copper signaling.

The next paper is from Emily Flashman’s lab at the University of Oxford and looks at the role of plant cysteine oxidases as oxygen sensors whilst the tenth paper features John Doonan (Aberystwyth University) as a co-author and investigates how a histone acetyltransferase affects trichome development.

Finally is a paper from Pierre Baudal and Kirsten Bomblies (John Innes Centre) that uses Arabidopsis arenosa as a model to investigate the emergence of novel flowering time alleles in populations that have colonised along railway corridors.

Sassmann S, Rodrigues C, Milne SW, Nenninger A, Allwood E, Littlejohn GR, Talbot NJ, Soeller C, Davies B, Hussey PJ, Deeks MJ (2018) An Immune-Responsive Cytoskeletal-Plasma Membrane Feedback Loop in Plants. Curr Biol. doi: 10.1016/j.cub.2018.05.014

https://www.sciencedirect.com/science/article/pii/S096098221830616X?via%3Dihub

Open Access

Stefan Sassmann is the lead author of this paper from Mike Deeks’s lab in Exeter. They investigate the role of the membrane-integrated FORMIN4 protein in the process of cell wall apposition, which occurs as part of the plant immune response and is dependent on actin dynamics. FORMIN4 is stably localised apart from the active traffic of the endomembrane system and removing its function compromises the defense response, presumably by altering actin distribution at sites of cell wall apposition. This work demonstrates that FORMIN4 acts as a key component of the pre-invasion defense response.

Gallego-Giraldo L, Posé S, Pattathil S, Peralta AG, Hahn MG, Ayre BG, Sunuwar J, Hernandez J, Patel M, Shah J, Rao X, Knox JP, Dixon RA (2018) Elicitors and defense gene induction in plants with altered lignin compositions. New Phytol. doi: 10.1111/nph.15258

Open Access

Sara Pose and Paul Knox (University of Leeds) are co-authors on this US-led study that investigates how lignin composition can influence the defence response. Plants with the same lignin content but changed lignin compositions show altered expression in genes involved with different arms of the defense response. This indicates that cell wall lignin composition plays a significant role in the plants ability to response to different sources of pathogen attack.

Engelsdorf T, Gigli-Bisceglia N, Veerabagu M, McKenna JF, Vaahtera L, Augstein F, Van der Does D, Zipfel C, Hamann T (2018) The plant cell wall integrity maintenance and immune signaling systems cooperate to control stress responses in Arabidopsis thaliana. Sci Signal. doi: 10.1126/scisignal.aao3070

Joe McKenna (Imperial College, now Oxford Brookes University) and Cyril Zipfel (The Sainsbury Laboratory, Norwich) are co-authors on this Norwegian-led study that looks at the plant cell wall integrity maintenance mechanism and how it responses to the challenges of growth, development and environmental stresses. They identified a set of receptor-like kinases that are key for the responses elicted by cell wall damage (CWD). Conversely they showed that the components of the pattern-triggered immunity (PTI) signaling pathway repress responses to CWD. This study provides insights into how cell wall responses interact with downstream gene expression changes following pathogen challenge.

Bömer M, O’Brien JA, Pérez-Salamó I, Krasauskas J, Finch P, Briones A, Daudi A, Souda P, Tsui TL, Whitelegge JP, Paul Bolwell G, Devoto A (2018) COI1-dependent jasmonate signalling affects growth, metabolite production and cell wall protein composition in Arabidopsis. Ann Bot. doi: 10.1093/aob/mcy109

Open Access

Moritz Bömer works with Alessandra Devoto at Royal Holloway University of London and leads this research that looks at the effect of MeJA treatment on growth and gene expression in Arabidopsis cell culture. They demonstrate that both MeJA treatment or COI1 overexpression causes changes in the abundance of proteins involved in cell wall loosening as well as altered levels of primary metabolites alanine, serine and succinic acid. This work demonstrates a close link between hormone signaling, the defence response and the metabolic profile of Arabidopsis cells.

Dr Devoto and her academic colleagues at RHUL are profiled in the latest GARNish newsletter available for download from the GARNet website.

Kriechbaumer V, Breeze E, Pain C, Tolmie F, Frigerio L, Hawes C (2018) Arabidopsis Lunapark proteins are involved in ER cisternae formation. New Phytol. doi: 10.1111/nph.15228

https://nph.onlinelibrary.wiley.com/doi/abs/10.1111/nph.15228

Open Access

Verena Kriechbaumer from Oxford Brookes University leads this research that investigates the in planta function of novel ER network-shaping proteins called Lunaparks (LNP). They show that these proteins localise to the entire ER network in Arabidopsis. They use confocal microscopy to show that altering the level of LNP gene expression changes ER morphology, possibly by regulating the formation of ER cisternae.

Chow M, Sklepari M, Frigerio L, Dixon AM (2018) Bacterial expression, purification and biophysical characterization of the smallest plant reticulon isoform, RTNLB13 Protein Expr Purif. doi: 10.1016/j.pep.2018.06.015

Open Access

Michael Chow worked with Lorenzo Frigerio and Ann Dixon at the University of Warwick to provide a preliminary structure and topology analysis of the plant RTNLB13 reticulon protein. This ER-associated integral membrane protein was expressed in bacteria and then a variety of analysis techniques were used to suggest that RTNLB13 has a high level of self-association and protein-membrane interactions.

Janes G, von Wangenheim D, Cowling S, Kerr I, Band L, French AP, Bishopp A (2018) Cellular Patterning of Arabidopsis Roots Under Low Phosphate Conditions Front Plant Sci. doi: 10.3389/fpls.2018.00735

https://www.frontiersin.org/articles/10.3389/fpls.2018.00735/full

Open Access

George Janes works with Anthony Bishopp at the University of Nottingham and leads this study that looks at root meristem development under low phosphate conditions. They show that in phosphate-limiting conditions the cortex layer of the root meristem contains almost double the number of cells, which results in a greater number of root hair-forming epidermal cells. As this change can occur within 24hrs the rapidity of the response represents a significant adaptation to a changing root environment.

Hippler FWR, Mattos-Jr D, Boaretto RM, Williams LE (2018) Copper excess reduces nitrate uptake by Arabidopsis roots with specific effects on gene expression J Plant Physiol. doi: 10.1016/j.jplph.2018.06.005

https://www.sciencedirect.com/science/article/pii/S0176161718302888

Open Access

Franz Hippler (University of Southampton) leads this UK-Brazil collaboration showing that growth of Arabidopsis plants in excess copper conditions causes a downregulation in nitrate uptake. This is due to both direct and indirect changes on the gene expression of nitrate transporters as well as a reduction in transcript level of the plasma membrane proton pump, AHA2. This effect was altered when copper levels were reduced demonstrating that copper toxicity acts at the level of nitrate transport and homeostasis.

White MD, Kamps JJAG, East S, Taylor Kearney LJ, Flashman E (2018) The Plant Cysteine Oxidases from Arabidopsis thaliana are kinetically tailored to act as oxygen sensors J Biol Chem.

doi: 10.1074/jbc.RA118.003496

Open Access

Mark White is the lead author on this work from the lab of Emily Flashman at the University of Oxford in which they look at the role of plant cysteine oxidases (PCOs) as oxygen sensors. They assessed the kinetics of each of AtPCO1 to AtPCO5 proteins and show that the most catalytically competent isoform is AtPCO4, in terms of both responding to O2, and oxidizing hypoxic responsive proteins. This work validates an O2-sensing role for the PCOs and provides evidence for functional differences between members of this enzyme family.

Kotak J, Saisana M, Gegas V, Pechlivani N, Kaldis A, Papoutsoglou P, Makris A, Burns J, Kendig AL, Sheikh M, Kuschner CE, Whitney G, Caiola H, Doonan JH, Vlachonasios KE, McCain ER, Hark AT (2018) The histone acetyltransferase GCN5 and the transcriptional coactivator ADA2b affect leaf development and trichome morphogenesis in Arabidopsis. Planta. doi: 10.1007/s00425-018-2923-9 Open Access

John Doonan (Aberystwyth University) is a co-author on this manuscript led by Jenna Kotak and Amy Herd in the USA. They investigate plants that have mutations in the histone acetyltransferase GCN5 and associated transcriptional coactivator ADA2b. These genes have been previously demonstrated as being involved in endoreduplication and trichome branching. They show that these mutants have alterations in the number and patterning of trichome-branches and that ADA2b and GCN5 are required to couple nuclear content with cell growth and morphogenesis.

Baduel P, Hunter B, Yeola S, Bomblies K. Genetic basis and evolution of rapid cycling in railway populations of tetraploid Arabidopsis arenosa (2018) PLoS Genet.

doi: 10.1371/journal.pgen.1007510 Open Access

Pierre Baduel and Kirsten Bomblies (John Innes Centre) lead this work that was conducted prior to Kirsten’s move to Norwich. In this study they follow the colonization of populations of Arabidopsis arenosa along mountain railway corridors. They demonstrate that selective pressure has occurred on novel alleles of flowering time genes and discuss the implications for ruderal communities linked to railways as allele conduits linked to local adaptations.

Arabidopsis Research Roundup: Nov 24th

by Geraint

Categories: Essex University, Glasgow University, Global, John Innes Centre, Nottingham University, SLCU, University of Bristol, University of Essex, University of Sheffield, University of Southampton

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Published on: November 24, 2017

The week’s UK Arabidopsis research roundup includes seven papers from groups who work on a range of topics.

Firstly Antony Dodd (Bristol) investigates the role of sugar signaling during hypocotyl elongation and provides an audio description of this groups work. Secondly Mike Holdsworth (Nottingham) leads a paper that demonstrates the importance of the N-rule pathway in the response to abiotic stresses. Thirdly are a set of papers that have developed models on three different topics. Mike Blatt’s group at Glasgow University has a cross-scale model that is applied to stomatal opening whilst Stan Maree and Veronica Griensien (JIC) use modeling to predict how the topology of pavement cells is determined. Finally Arabidopsis is used as an example that fits a model that investigates how critical mutation rate (CMR) changes with population size. In the sixth paper Lorraine Williams and colleagues (University of Southampton) investigate the function of a rice transport protein involved in manganese tolerance by expressing it in Arabidopsis. The final paper from Jerzy Paszkowski (SLCU) outlines a novel screening strategy for retrotransposons and the identification of an ecotype specific element.

Simon NM, Kusakina J, Fernández-López Á, Chembath A, Belbin FE, Dodd AN (2017) The energy-signalling hub SnRK1 is important for sucrose-induced hypocotyl elongation. Plant Physiol. doi: 10.1104/pp.17.01395

Open Access

This UK-wide collaboration is led by Anthony Dodd at the University of Bristol and has looked at the factors that control hypocotyl elongation in response to sugar signalling. This response is integrated through the sugar-signalling hub, SnRK1 and is regulated by trehalose-6-phosphate (Tre6P). They also integrate hormone signalling and the influence of diurnal rhythms into the control of this process, importantly showing that the ubiquitous sugar regulator hexokinase is not involved in this process.

Antony kindly provides an audio description of this research that can be found on YouTube or on the GARNet iTunes channel. Please subscribe!

Vicente J, Mendiondo GM, Movahedi M, Peirats-Llobet M, Juan YT, Shen YY, Dambire C, Smart K, Rodriguez PL, Charng YY, Gray JE, Holdsworth MJ (2017) The Cys-Arg/N-End Rule Pathway Is a General Sensor of Abiotic Stress in Flowering Plants. Current Biology doi: 10.1016/j.cub.2017.09.006

Open Access

Mike Holdsworth (University of Nottingham) is the corresponding author of this collaboration with colleagues from Sheffield, Spain and Taiwan that investigates how the N-rule degradation pathway acts a sensor of general abiotic stress in both Arabidopsis and Barley. These responses are integrated through degradation of the group VII Ethylene Response Factor transcription factors (ERFVIIs) family via direct and indirect pathways. In addition they link ERFVII activity with chromatin-remodeling ATPase BRAHMA providing evidence for a single mechanism that links the responses to a number of environmental signals.

Wang Y, Hills A, Vialet-Chabrand SR, Papanatsiou M, Griffiths H, Rogers S, Lawson T, Lew V, Blatt MR (2017) Unexpected Connections between Humidity and Ion Transport Discovered using a Model to Bridge Guard Cell-to-Leaf Scales. Plant Cell. doi: 10.1105/tpc.17.00694

Open Access

Mike Blatt (University of Glasgow) leads this collaboration with researchers at the Universities of Cambridge and Essex. They have developed the OnGuard2 quantitative systems platform that integrates numerous parameters that control guard cell dynamics across many scales including at molecular, cellular, tissue and canopy levels. They experimentally demonstrate that OnGuard2 faithfully reproduces the kinetics of real stomatal movement and therefore that this modeling is able to bridge the micro-macro divide.

Carter R, Sánchez-Corrales YE, Hartley M, Grieneisen VA, Marée AFM (2017) Pavement cells and the topology puzzle. Development. doi: 10.1242/dev.157073

Stan Maree and Veronica Griensien (John Innes Centre) lead this study that has looked at the patterning of 50000 Arabidopsis pavement cells to understand the topological signatures that exist in this population. They have developed a heuristic cellular division rule to produce a model that can reproduce their observations by predicting how these cells divide. They confirmed their model by tracking 800 mitotic events, allowing them to conclude that distinct topology is not a direct consequence of the jigsaw-like shape of the cells, but rather owes itself to life-history-driven process, with limited impact from cell surface mechanics.

Aston E, Channon A, Belavkin RV, Gifford DR, Krašovec R, Knight CG (2017) Critical Mutation Rate has an Exponential Dependence on Population Size for Eukaryotic-length Genomes with Crossover. Sci Rep. doi: 10.1038/s41598-017-14628-x

Open Access

In this study a team of computational biologists from Keele, Middlesex and Manchester have used Arabidopsis as an exemplar to understand how critical mutation rate (CMR) provides insights into the shift between survival-of-the-fittest and survival of individuals with greater mutational robustness. They have produced a simulation for these parameters that predicts outcomes for a range of biological organisms, showing that CMR decreases with reduced population size. They suggest that the model can be used to understand the conservation strategies exhibited in populations that are approaching extinction.

Farthing EC, Menguer PK, Fett JP, Williams LE (2017) OsMTP11 is localised at the Golgi and contributes to Mn tolerance. Sci Rep. doi: 10.1038/s41598-017-15324-6
Lorraine Williams (University of Southampton) and her colleagues have identified a transporter protein from rice, OsMTP11 that is involved in mangenase tolerance. They show that heterologous expression of this protein is able to rescue the manganese sensitive phenotype of Arabidopsis mtp11-3 knockouts. They show that OsMTP11 localises to the Golgi and have also conducted site directed mutagenesis to identify key residues that are important for the function of this protein.

Griffiths J, Catoni M, Iwasaki M, Paszkowski J (2017) Sequence-independent identification of active LTR retrotransposons in Arabidopsis. Mol Plant. doi: 10.1016/j.molp.2017.10.012

Open Access

Jerzy Paszkowski (SLCU) leads this single-figure short manuscript that has characterised the population of retrotransposons in Arabidopsis. They develop a novel cost-effective screening strategy that allows them to identify sequences found on extrachromosomal DNA (ecDNA), which includes a retroelement found in Lansberg erecta but not in the reference genome ecotype Col-0.

Arabidopsis Research Roundup: January 11th

by Geraint

Categories: Bristol University, Cambridge University, Glasgow University, Global, John Innes Centre, methods, Open Access, Uncategorized, University of Southampton, Warwick University

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Published on: January 11, 2017

The first Arabidopsis Research Roundup of 2017 includes a wide range of studies that use our favourite model organism.

Firstly Kerry Franklin (University of Bristol) is the corresponding author on a paper that describes the complex interaction between the responses to sunlight and heat. Secondly Paul Dupree (University of Cambridge) leads a study that defines the important structural relationship between xylan and cellulose. Thirdly members of Gos Micklem’s group in Cambridge are part of the Araport team that present their ThaleMine tool.

Richard Napier (University of Warwick) is a co-author on the fourth paper that introduces a new chemical tool for study of the auxin response. The penultimate paper includes Matthew Terry (University of Southampton) on a paper that investigates the role of a Fe-S-containing protein cluster in chlorophyll biosynthesis and finally there is a methods paper from Stefanie Rosa in Caroline Dean’s lab at the John Innes Centre that describes the use of FISH to detect single molecules of RNA.

Hayes S, Sharma A, Fraser DP, Trevisan M, Cragg-Barber CK, Tavridou E, Fankhauser C, Jenkins GI, Franklin KA (2016) UV-B Perceived by the UVR8 Photoreceptor Inhibits Plant Thermomorphogenesis. Current Biology http://dx.doi.org/10.1016/j.cub.2016.11.004

Open Access

This collaboration between the research groups of Kerry Franklin (University of Bristol) and Gareth Jenkins (University of Glasgow) looks at how the perception of UV-B light inhibits the morphological changes that occur in response to increased temperatures (thermomorphogenesis). This response includes induced hypocotyl elongation, which is mediated via PIF4 and various players in the auxin response. Interestingly the authors show that UV-B light perceived by UVR8 attenautes this response by preventing PIF4 abundance and by stabilising the the bHLH protein LONG HYPOCOTYL IN FAR RED (HFR1) protein. These results suggest that there exists a precise mechanism for fine-tuning the growth responses that occur in sunlight that would usually include both increased temperature and UV-B irradiation.

Simmons TJ, Mortimer JC, Bernardinelli OD, Pöppler AC, Brown SP, deAzevedo ER, Dupree R, Dupree P (2016) Folding of xylan onto cellulose fibrils in plant cell walls revealed by solid-state NMR. Nat Commun.

http://dx.doi.org/10.1038/ncomms13902 Open Access
In this paper Paul Dupree (University Cambridge) collaborates both with colleagues in Spain and with his father Ray, who is a physicist at the University of Warwick. They use NMR to perform a structural analysis of xylan, which is the most prevalent non-cellulosic polysaccharide in the cell wall matrix and binds to cellulose microfibrils. Whereas in solution xylan forms a threefold helical screw, it flattens into a twofold helical screw ribbon to closely bind to cellulose when in the cell wall. They used the cellulose-deficient Arabidopsis irx3 mutant to show that the xylan two-fold screw confirmation breaks down when it cannot bind cellulose. The authors state that this finding has important implications in our understanding of the formation of the cell wall and perhaps more importantly how it might be broken down during attempts to maximise economic usages of plant biomass.

A local Cambridge newspaper reported that this finding could ‘pave the way for wooden skyscrapers’

Krishnakumar V, Contrino S, Cheng CY, Belyaeva I, Ferlanti ES, Miller JR, Vaughn MW, Micklem G, Town CD, Chan AP (2016) ThaleMine: A Warehouse for Arabidopsis Data Integration and Discovery. Plant Cell Physiol http://dx.doi.org/10.1093/pcp/pcw200 Open Access

This paper is presented by the Araport team, which is based in the USA but includes representatives from Gos Micklem’s lab in University of Cambridge. They outline the functionality of the ThaleMine data warehouse which is an important component of the tools included on Araport (https://www.araport.org/). ThaleMine collects a wide variety of data from public datasets and presents it in a easy-to-interrogate form, facilitating the experiments of both lab-based researchers or bioinformaticians. This tool is build upon the InterMine software framework, which has been widely adopted across other model organisms.

Chris Town and Sergio Contrino provided a hands-on workshop describing the tools on Araport in last year GARNet2016 meeting and their workshop materials can be downloaded here.

Steenackers WJ, Klíma P, Quareshy M, Cesarino I, Kumpf RP, Corneillie S, Araújo P, Viaene T, Goeminne G, Nowack MK, Ljung K, Friml J, Blakeslee JJ, Novák O, Zažímalová E, Napier RM, Boerjan WA, Vanholme B (2016) cis-cinnamic acid is a novel, natural auxin efflux inhibitor that promotes lateral root formation. Plant Physiol. http://dx.doi.org/pp.00943.2016 Open Access

This pan-european collaboration includes members of Richard Napier’s lab at the University of Warwick. They outline the activity of a novel inhibitor of auxin efflux transport called cis-cinnamic acid (c-CA). When c-CA is applied to growth media plants appears to exhibit an auxin-response phenotype yet these experiments show that c-CA is neither an auxin or anti-auxin and in fact blocks local auxin efflux, thus causing buildup of cellular auxin. This effect does not occur with t-CA showing specificity for c-CA and it does not affect long distance auxin transport, which occurs through the phloem. Therefore this paper presents a new pharamolgical tool for the study of in planta auxin transport and homeostasis.

Hu X, Page MT, Sumida A, Tanaka A, Terry MJ, Tanaka R (2016) The iron-sulfur cluster biosynthesis protein SUFB is required for chlorophyll synthesis, but not phytochrome signaling. Plant J.

http://dx.doi.org/10.1111/tpj.13455

Matthew Terry and Mike Page (University of Southampton) are co-authors on this Japanese-led study that investigates the function of the SUFB subunit of the SUFBCD iron-sulfur cluster. These Fe-S protein clusters play roles in many metabolic processes and the SUFB mutant hmc1 exhibits a defect in chlorophyll biosynthesis due to an accumulation of Mg-containing biosynthetic intermediates. In addition both SUFC- and SUFD-deficient RNAi lines accumulated the same Mg intermediate indicating that the SUFBCD cluster is responsible for this step necessary for chlorophyll production.

Duncan S, Olsson TS, Hartley M, Dean C, Rosa S (2016) A method for detecting single mRNA molecules in Arabidopsis thaliana. Plant Methods. http://dx.doi.org/10.1186/s13007-016-0114-x

Open Access
This paper from is lead by Stefanie Rosa in Caroline Dean’s lab at the John Innes Centre describes a novel method for imaging single molecules of RNA by smFISH. They analyse the localisation of both nascent and mature mRNAs, allowing for analysis of the location of RNA processing and translation.<

Arabidopsis Research Roundup: January 22nd 2016

by Geraint

Categories: Arabidopsis, bioinformatics, Cambridge University, Essex University, Global, Light Signaling, University of Leeds, University of Southampton, University of York

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Comments: 1 Comment

Published on: January 22, 2016

A mixed selection of research in this UK Arabidopsis Roundup. Firstly a study from Stefan Kepinski and Mark Estelle that adds another layer of understanding to the regulation of the auxin response. Enrique Lopez-Juez leads a study into signaling between the nucleus and chloroplast while Tracey Lawson contributes to an investigation into role of starch metabolism in guard cells. Fran Maathuis and co-worker looks at differences in vacuolar transport between Arabidopsis ecotypes while Alan Marchant is involved in a study of cell wall pectins. Finally William Amos has uses the 1001genomes project to investigate heterozygote instability (HI).

Wang R, Zhang Y, Kieffer M, Yu H, Kepinski S, Estelle M (2016) HSP90 regulates temperature-dependent seedling growth in Arabidopsis by stabilizing the auxin co-receptor F-box protein TIR1. Nat Commun. 5;7:10269. http://dx.doi.org/10.1038/ncomms10269 Open Access

Stefan Kepinski (Leeds) is the UK lead on this collaboration with Mark Estelle from UCSD and it continues their previous work that investigates the much-studied auxin receptor TIR1. Arabidopsis seedlings grown at 29C show auxin-dependent hypocotyl elongation although the molecular mechanism behind this response has remained opaque. In this study they show that in high temperatures TIR1 accumulates in a manner dependent on the molecular chaperone, HSP90. In addition HSP90 and the co-chaperone SGT1 directly interact with TIR1. Inhibition of HSP90 results in degradation of the TIR1 and causes a range of auxin-mediated growth processes at both high and low temperatures. This study adds another level of complexity to the molecular basis of the auxin response.

Hills AC, Khan S, López-Juez E (2015) Chloroplast Biogenesis-Associated Nuclear Genes: Control by Plastid Signals Evolved Prior to Their Regulation as Part of Photomorphogenesis. Front Plant Sci. 10;6:1078. http://dx.doi.org/10.3389/fpls.2015.01078 Open Access

The work comes exclusively from the lab of Enrique Lopez-Juez at Royal Holloway and investigates at the expression of photosynthesis-associated nuclear genes (PhANGs). This expression is dependent on light as well as plastid-to-nucleus “biogenic” communication signals and causes the assembly of photosynthesis component chloroplasts. The authors investigate the factors that control the activity of the Lhcb promotor in the light and the dark, both in angiosperms and gymnosperms. They propose that suppression of PhANG responses has contributed to the evolution of light-controlled chloroplast biogenesis.

Horrer D, Flütsch S, Pazmino D, Matthews JS, Thalmann M, Nigro A, Leonhardt N, Lawson T, Santelia D (2015) Blue Light Induces a Distinct Starch Degradation Pathway in Guard Cells for Stomatal Opening. Current Biology http://dx.doi.org/10.1016/j.cub.2015.12.036

Tracey Lawson (University of Essex) is the UK lead on this UK-French-Swiss study that uses the stomatal guard cell experimental system to investigate the role of carbon metabolism in the response to blue light. Interestingly guard cells differ from other leave tissues in that they contain starch at the end of the night. However this starch store is rapidly degraded within 30minutes of light and is important for stomatal opening and subsequent biomass production. This starch degradation involves action of two enzymes, β-amylase 1 (BAM1) and α-amylase 3 (AMY3) that do not function during night time starch degradation in other tissues. This process is coordinated by blue light signalling and correlates with the activity of a plasma membrane ATPase. This study adds yet another level of our understanding into the mechanism of stomatal opening. See image for a proposed model of this process (from Cell Press).

Hartley TN, Maathuis FJ (2015) Allelic variation in the vacuolar TPK1 channel affects its calcium dependence and may impact on stomatal conductance. FEBS Lett. 90(1):110-7 http://dx.doi.org/10.1002/1873-3468.12035

Fran Maathuis (University of York) is the leader on this study that assesses the transport properties of two different vacuolar-localised AtTPK1 alleles identified for a study of natural variation in Arabidopsis. They use patch-clamping the interrogate the difference between these proteins from Lansberg (Ler) and Kas-2 ecotypes, when they showed different levels of Ca(2+) dependence. This coincided with lower water loss in either the presence of absence of ABA and higher Ler AtTPK1 activity at similar cytoplasmic [Ca]. The authors present a model that helps to explain their findings.

Dumont M, Lehner A, Vauzeilles B,, Malassis J, Marchant A, Smyth K, Linclau B, Baron A, Mas Pons J, Anderson CT, Schapman D, Galas L, Mollet JC, Lerouge P (2015) Plant cell wall imaging by metabolic click-mediated labelling of rhamnogalacturonan II using azido 3-deoxy-D-manno-oct-2-ulosonic acid. Plant Journal. http://dx.doi.org/10.1111/tpj.13104

The majority of the authors on this Technical Advance are from French institutions but also includes UK plant scientist Alan Marchant (University of Southampton). They investigate the chemistry of Arabidopsis and tobacco cell walls, specifically looking at the incorperation of 3-deoxy-D-manno-oct-2-ulosonic acid (Kdo), a monosaccharide that is only found the cell wall pectin rhamnogalacturonan-II (RG-II). They show that RG-II is found in the primary cell wall including within the root elongation zone. Finally they show that monitoring of Kdo is an effective way to study the synthesis and redistribution of RG-II during root growth.

Amos W (2015) Heterozygosity increases microsatellite mutation rate. Biol Lett. http://dx.doi.org/10.1098/rsbl.2015.0929 Open Access

This study is led by Professor William Amos who is based in the Zoology department at Cambridge. He is not usually a plant science researcher but used the excellent 1001genome project to investigate heterozygote instability (HI) in Arabidopsis. He looked at AC microsatellite sequences from over 1100 genome sequences and used rare alleles as a surrogate for more recent mutations, ultimately showing that rare alleles are more likely to occur at locus-population combinations with higher heterozygosity even when all populations carry exactly the same number of alleles. This shows that local heterozygosity causes more mutations and represents a positive feedback loop.

Arabidopsis Research Roundup: November 25th

by Geraint

Categories: Arabidopsis, bioinformatics, Exeter University, GARNet, Global, John Innes Centre, Oxford University, plant pathogens, Plant Physiology, Uncategorized, University of Oxford, University of Southampton, Warwick University

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Comments: 1 Comment

Published on: November 25, 2015

This weeks Arabidopsis Research Roundup contains four papers each with a different focus. Firstly is a large-scale investigation that attempts to define the transcriptional changes that occur in response to bacterial infection. Second is a study that investigates a newly proposed role for the chloroplast chaperone Hsp93. Thirdly is another piece of work that also involves University of Oxford researchers and investigates the genetic networks that control leaf morphology. Finally is an updated plant-specific protocol for the commonly used technique of Chromatin Immunoprecipitation.

Lewis LA, Polanski K, de Torres-Zabala M, Jayaraman S, Bowden L, Moore J, Penfold CA, Jenkins DJ, Hill C, Baxter L, Kulasekaran S, Truman W, Littlejohn G, Prusinska J, Mead A, Steinbrenner J, Hickman R, Rand D, Wild DL, Ott S, Buchanan-Wollaston V, Smirnoff N, Beynon J, Denby K, Grant M (2015) Transcriptional Dynamics Driving MAMP-Triggered Immunity and Pathogen Effector-Mediated Immunosuppression in Arabidopsis Leaves Following Infection with Pseudomonas syringae pv tomato DC3000 Plant Cell. http://dx.doi.org/10.1105/tpc.15.00471 Open Access

This ‘Large Scale Biology’ publication is a collaboration between the Universities of Exeter and Warwick, led by Murray Grant and current GARNet Advisory board member Katherine Denby. This study investigates the transcriptional changes that occur over a long time course in response to infection by the pathogen Pseudomonas syringae pv tomato DC3000. The authors aim to differentiate between the changes associated with endogenous microbial-associated molecular pattern (MAMP)-triggered immunity (MTI) and those orchestrated by pathogen effectors. The responses to pathogenic and non-pathogenic P.syringae were compared and using novel computational analysis, it was shown that the majority of gene expression changes that contribute to disease or defense responses occurred within 6hour post-infection, well before pathogen multiplication. Broadly it was found that chloroplast-associated genes are suppressed by a MAMP-triggered response, presumably to restrict nutrient availability. Ultimately this manuscript identified specific promotor elements that are involved in either the MTI response or utilised by the infecting bacteria.

Corresponding author Professor Murray Grant kindly takes ten minutes to discuss the finding of this paper and the community resource that it represents. He also discusses another paper involving the Jasmonate response that resulted from this dataset and was recently highlighted in the Research Roundup. Interview end at 11m10s.

Flores-Pérez Ú1, Bédard J1, Tanabe N2, Lymperopoulos P2, Clarke AK3, Jarvis P (2015) Functional analysis of the Hsp93/ClpC chaperone at the chloroplast envelope Plant Physiology. http://dx.doi.org/10.1104/pp.15.01538 Open Access

Paul Jarvis (Oxford) is the corresponding author on this study in which his lab collaborates with Swedish researchers to investigate the role of the Hsp93/ClpC chaperone protein in protein import into the chloroplast. This recently postulated role for this protein has not yet been experimental tested so they generated a hsp93[P-] mutant that lacked a functional ClpP-binding motif (PBM), which confers the already determined role for Hsp93 in proteolysis that occurs in the chloroplast stroma. The hsp93[P-] mutant localises to the chloroplast envelope and associates with TIC transport machinery but was unable to complement the phenotypes of a hsp93 null mutant. This showed that the PBM domain was essential for its function. Expression of the Hsp93[P-] mutant in the hsp93 null background did not improve protein import so the authors concluded that these results do not confirm this newly postulated role for the protein and they suggest that its functional role occurs immediately after its substrate had been transported into the chloroplast.

Rast-Somssich MI, Broholm S, Jenkins H, Canales C, Vlad D, Kwantes M, Bilsborough G, Dello Ioio R, Ewing RM, Laufs P, Huijser P, Ohno C, Heisler MG, Hay A, Tsiantis M (2015) Alternate wiring of a KNOXI genetic network underlies differences in leaf development of A. thaliana and C. hirsuta Genes Dev. 29(22):2391-404 http://dx.doi.org/10.1101/gad.269050.115 Open Access

The study includes researchers from Oxford and Southampton Universities in collaboration with those from Italy, France and Germany in work that is led by Angela Hay and Miltos Tsiantis, who were both previously based in Oxford. This is familiar territory for this group as they compare leaf development between Arabidopsis, which has simple leaves, and the related , Cardamine hirsuta, which has dissected leaves. In this new work they transfer the SHOOTMERISTEMLESS (STM) and BREVIPEDICELLUS (BP) homeobox genes between the two species and investigate their ability to modify leaf form. In Cardamine, expression of BP is controlled by crosstalk between the microRNA164A (MIR164A)/ChCUP-SHAPED COTYLEDON (ChCUC) module and ChASYMMETRIC LEAVES1 (ChAS1) gene. However this regulatory network does not function in Arabidopsis and therefore leads to the establishment of differing regulatory networks that the authors propose are responsible for the alterations in organ geometry.

Posé D, Yant L (2016) DNA-Binding Factor Target Identification by Chromatin Immunoprecipitation (ChIP) in Plants Methods Mol Biol. 1363:25-35. http://dx.doi.org/10.1007/978-1-4939-3115-6_3

Levi Yant is a new member of faculty at the John Innes Centre and is the lead author on this paper that introduces an updated protocol for Chromatin Immunoprecipitation in Plants (ChIP). They have used this technique in his lab to identify target genes for a number of transcriptional regulators that are involved in Arabidopsis floral development.

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