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GARNet Research Roundup: May 7th 2020

Categories: Edinburgh University, Glasgow University, Global, John Innes Centre, Sainsbury Lab, Uncategorized, University of Bristol, University of Cambridge, University of Edinburgh, University of Glasgow

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Published on: May 7, 2020

This edition of GARNet Research Roundup begins with two studies from the John Innes Centre. The first takes a detailed look at meiosis in Arabidopsis arenosa and the second introduces a novel mode of auxin perception.

The third paper from the Grierson lab in Bristol uses innovative methods to assess root-soil cohesion through study of root hairs. The fourth paper is also from Bristol and looks at the evolution of stomata.

The fifth and sixth papers are from Scotland. Firstly researchers at Edinburgh have developed a deep learning approach for plant phenotyping whilst in the second research from Glasgow looks at the role of UVR8 in the UV response of UV-B adapted plants.

The seventh paper is from The Sainsbury lab, Norwich and reveals a new role for phosphorylation in the formation of the RRS1-R/RPS4 immune receptor complex.

The final paper includes co-authors from Cambridge and looks at the role of epigenetic changes in the reponse to an experimentally evolved plant virus.

Morgan C, Zhang H, Henry CE, Franklin FCH, Bomblies K (2020) Derived alleles of two axis proteins affect meiotic traits in autotetraploid Arabidopsis arenosa. Proc Natl Acad Sci U S A. doi: 10.1073/pnas.1919459117 Open Access

Chris Morgan works at the John Innes Centre and leads this research that looks at meiosis in Arabidopsis arenosa. They use super resolution microscopy to look in great detail at the intertaction of the ASY1 and ASY3 loci. Chris discussed this work on the GARNet community podcast.

Kuhn A, Ramans Harborough S, McLaughlin HM, Natarajan B, Verstraeten I, Friml J, Kepinski S, Østergaard L (2020) Direct ETTIN-auxin interaction controls chromatin states in gynoecium development. Elife doi: 10.7554/eLife.51787 Open Access

Andre Kuhn works with Lars Ostergaard at the John Innes Centre and leads this research that has identified a novel mode of auxin perception in which the ETTIN transcription factor directly interacts with auxin. This allows a rapid response that does not rely on the canonical mode of auxin perception via protein degradation. Andre discussed this work on the GARNet community podcast.

De Baets S, Denbigh TDG, Smyth KM, Eldridge BM, Weldon L, Higgins B, Matyjaszkiewicz A, Meersmans J, Larson ER, Chenchiah IV, Liverpool TB, Quine TA, Grierson CS (2020) Micro-scale interactions between Arabidopsis root hairs and soil particles influence soil erosion. Commun Biol. doi: 10.1038/s42003-020-0886-4 Open Access

This work from the University of Bristol is led by Sarah De Baets S, Tom Denbigh, Kevin Smyth, Beth Eldridge. They have developed a series o fthree innovative assays to investigate the role of root hairs in the cohesion of the roots-soil interaction. This research shows that root hairs play a significant role in this process. Tom and Beth discussed this work on the GARNet community podcast.

Harris BJ, Harrison CJ, Hetherington AM, Williams TA (2020) Phylogenomic Evidence for the Monophyly of Bryophytes and the Reductive Evolution of Stomata. Curr Biol. doi: 10.1016/j.cub.2020.03.048 Open Access

This paper from the University of Bristol is led by Brogan Harris and investigates the evolutionary origins of genes that specify stomatal development and function in bryophytes. They show that important stomatal lineage genes are present in bryophytes, indicating that their stomata have undergone reductive evolution.

https://linkinghub.elsevier.com/retrieve/pii/S0960-9822(20)30418-8

Dobrescu A, Giuffrida MV, Tsaftaris SA (2020) Doing More With Less: A Multitask Deep Learning Approach in Plant Phenotyping. Front Plant Sci. 2020 Feb 28;11:141. doi: 10.3389/fpls.2020.00141 Open Access

Andrei Dobrescu leads this methods paper from the University of Edinburgh that uses multitask deep learning to develop software for plant phenotying. They test their method on the analysis of Arabidopsis rosettes.

https://www.frontiersin.org/articles/10.3389/fpls.2020.00141/full

Liao X, Liu W, Yang HQ, Jenkins GI (2020) A dynamic model of UVR8 photoreceptor signaling in UV-B-acclimated Arabidopsis. New Phytol. doi: 10.1111/nph.16581 Open Access

Xinyang Liao leads this work from the University of Glasgow that continues the Jenkins’ lab research on the UVR8 photoreceptor. In this paper they analysed the role of UVR8 in UV-B-acclimated plants in which the switch between between monomeric and dimeric states can response to high UV-B without the need for new translation. This response is also alters the interaction of UVR8 with the COP1 and RUP2 proteins.

https://nph.onlinelibrary.wiley.com/doi/abs/10.1111/nph.16581

Guo H, Ahn HK, Sklenar J, Huang J, Ma Y, Ding P, Menke FLH, Jones JDG (2020) Phosphorylation-Regulated Activation of the Arabidopsis RRS1-R/RPS4 Immune Receptor Complex Reveals Two Distinct Effector Recognition Mechanisms. Cell Host Microbe. doi: 10.1016/j.chom.2020.03.008

Hailong Guo and Hee-Kyung Ahn work with Jonathan Jones at the Sainsbury lab, Norwich and lead this work that investigates the role of phosphorylation in the formation of the RRS1-R/RPS4 Immune Receptor Complex. This response is different to the effector-triggered conformational changes of RRS1 and represents a distinct novel route for immune signalling.

https://www.sciencedirect.com/science/article/abs/pii/S1931312820301724?via%3Dihub

Corrêa RL, Sanz-Carbonell A, Kogej Z, Müller SY, Ambrós S, López-Gomollón S, Gómez G, Baulcombe DC, Elena SF (2020) Viral Fitness Determines the Magnitude of Transcriptomic and Epigenomic Reprogramming of Defense Responses in Plants. Mol Biol Evol. doi: 10.1093/molbev/msaa091

This Spanish led study includes Regis Corrêa as lead author and includes David Baulcombe from Cambridge as a co-author. They infected Arabidopsis with an ancestral and experimentally-evolved isolates of turnip mosaic potyvirus (TuMV). The evolved version was more virulent and triggered a greater transcriptomic response in the plant as well inducing other epigenetic changes.

GARNet Research Roundup: April 9th 2020

by Geraint

Categories: Bristol University, Cambridge University, Glasgow University, Global, John Innes Centre, RHUL, Rothamsted Research, Sainsbury Lab, Uncategorized, University of Birmingham, University of Cambridge, University of Glasgow

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Published on: April 9, 2020

This Easter edition of the GARNet Research Roundup begins with research from Aberystwyth University that has developed a system for studying self-incompatability in self-compatible Arabidopsis. Next is an outstanding community-focussed study led from the John Innes Centre that outlines the development of new resources that better enable discovery-led science to be conducted within hexaploid wheat.

Third is a study led by the Dodd group at the JIC that links the circadian clock to water-use efficiency. The fourth paper is from the Edwards group at Bristol investigates the effect of higher temperatures on meiotic recombination in wheat. The fifth paper is from Rothamsted Research and introduces novel molecular tools that will be useful in future studies of the economically important weed Blackgrass.

The next paper includes co-authors from the Sainsbury lab in Norwich and looks at the role of carbonic anhydrases in plant immunity at higher levels of CO2. The seventh paper looks at the integration of light signaling and the circadian clock and includes Paul Devlin from RHUL as a co-author. The penultimate paper includes Gareth Jenkins from Glasgow as a co-author and looks at the perception of different wavelengths of UV light by the photoreceptor UVR8. The final paper includes Marko Hyvönen from Cambridge as a co-author and investigates the organisation of the RALF gene family in strawberry.

Wang L, Triviño M, Lin Z, Carli J, Eaves DJ, Van Damme D, Nowack MK, Franklin-Tong VE, Bosch M (2020) New opportunities and insights into Papaver self-incompatibility by imaging engineered Arabidopsis pollen. J Exp Bot. doi: 10.1093/jxb/eraa092 Open Access

Ludi Wang is first author on this work led from Maurice Bosch’s lab at Aberystwyth University. They have transferred their work on self-incompatability (SI) in Papaver into Arabidopsis, so as to take advantage of its excellent genetic resources. They show that the SI response can be recapitulated in Arabidopsis, even though it is self-compatible. This research has allowed them to discover new roles for clathrin-mediated endocytosis, the actin cytoskeleton and calcium signaling during SI.

Ludi and Maurice discuss this work on the GARNet Community podcast.

Adamski NM, Borrill P, Brinton J, Harrington SA, Marchal C, Bentley AR, Bovill WD, Cattivelli L, Cockram J, Contreras-Moreira B, Ford B, Ghosh S, Harwood W, Hassani-Pak K, Hayta S, Hickey LT, Kanyuka K, King J, Maccaferrri M, Naamati G, Pozniak CJ, Ramirez-Gonzalez RH, Sansaloni C, Trevaskis B, Wingen LU, Wulff BB, Uauy C (2020) A roadmap for gene functional characterisation in crops with large genomes: Lessons from polyploid wheat. Elife. doi: 10.7554/eLife.55646 Open Access

This research is led from the Uauy lab at the John Innes Centre by Nikolai Adamski, Phillippa Borrill (now at Birmingham), Jemima Brinton, Sophie Harrington and Clemence Marchal. This team worked with collaborators based around the UK, in Australia, Canada and Mexico and they outline the resources that they have developed that will promote the use of wheat as an experimental organism for discovery-led research.

https://elifesciences.org/articles/55646

Simon NM, Graham CA, Comben NE, Hetherington AM, Dodd AN (2020) The circadian clock influences the long-term water use efficiency of Arabidopsis. Plant Physiol. doi: 10.1104/pp.20.00030 Open Access

This research is led by Noriane Simon who worked with Anthony Dodd at the University of Bristol and the John Innes Centre. They showed that misregulation of components that control the circadian oscillator causes alterations in water-use efficiency in Arabidopsis plants. This response is linked to the control of transpiration via circadian control of guard cell physiology.

Coulton A, Burridge AJ, Edwards KJ (2020) Examining the Effects of Temperature on Recombination in Wheat. Front Plant Sci. doi: 10.3389/fpls.2020.00230 Open Access

Alexander Coulton is lead author on this study from the University of Bristol that has looked at how temperature changes alter the landscape of meiotic recombination in wheat. Despite showing that high temperature induces movement of recombination events toward centromeres, the overall effect is limited due to the tight linkages of many wheat genes.

Mellado-Sánchez M, McDiarmid F, Cardoso V, Kanyuka K, MacGregor DR (2020) Virus-mediated transient expression techniques enable gene function studies in black-grass. Plant Physiol. doi: 10.1104/pp.20.00205 Open Access

This Letter to the editor of Plant Physiology is led by Macarena Mellado-Sánchez, who works with Dana MacGregor at Rothamsted Research. They demonstrate the first usage of Virus-mediated gene silencing (VIGS) and Virus-mediated protein overexpression (VOX) in Blackgrass, which is a significant crop weed. They use these techniques in genetic gain and loss of function studies that result in changes in herbicide resistance in transformed blackgrass. Hopefully this work can be a prelude to future research in this potentially important experimental system for understanding how weeds effect crop yields.

http://www.plantphysiol.org/content/early/2020/04/01/pp.20.00205.long

Zhou Y, Vroegop-Vos IA, Van Dijken AJH, Van der Does D, Zipfel C, Pieterse CMJ, Van Wees SCM (2020) Carbonic anhydrases CA1 and CA4 function in atmospheric CO(2)-modulated disease resistance. Planta. doi: 10.1007/s00425-020-03370-w

Yeling Zhou is first author on this Dutch-led research that includes Dieuwertje Van der Does and Cyril Zipfel from the Sainsbury lab in Norwich. They show that the Carbonic anhydrases CA1 and CA4 play a role in plant immunity under higher levels of atmospheric CO2. This indicates that these genes might be future targets for improving plant disease resistance.

Liu Y, Ma M, Li G, Yuan L, Xie Y, Wei H, Ma X, Li Q, Devlin PF, Xu X, Wang H (2020) Transcription Factors FHY3 and FAR1 Regulate Light-induced CIRCADIAN CLOCK ASSOCIATED1 Gene Expression in Arabidopsis. Plant Cell. doi: 10.1105/tpc.19.00981

Paul Devlin from RHUL is a co-author on this Chinese-study led by Yang Liu. They show that FAR-RED ELONGATED HYPOCOTYL3 (FHY3) and its paralogue FAR-RED IMPAIRED RESPONSE1 (FAR1) are essential for light induction of CCA1, which contracts to the repressive effect of PHYTOCHROME INTERACTING FACTOR 5 (PIF5). They introduce an integrated photosensory signaling pathway that brings together light signalling with control of the circadian clock.

Rai N, O’Hara A, Farkas D, Safronov O, Ratanasopa K, Wang F, Lindfors AV, Jenkins GI, Lehto T, Salojärvi J, Brosché M, Strid Å, Aphalo PJ, Morales LO. (2020) The photoreceptor UVR8 mediates the perception of both UV-B and UV-A wavelengths up to 350 nm of sunlight with responsivity moderated by cryptochromes. Plant Cell Environ. doi: 10.1111/pce.13752 Open Access

Neha Rai is first author on this Finnish-led study that includes Gareth Jenkins from the University of Glasgow as a co-author. They investigated the response of the photoreceptors UV RESISTANCE LOCUS 8 (UVR8) and CRYPTOCHROMES 1 and 2 (CRYs) to UV wavelengths included in sunlight. They show that the wavelength of 350 nm is an important cut-off for the perception of UV-B and UV-A by these different photoreceptors.

https://onlinelibrary.wiley.com/doi/full/10.1111/pce.13752

Negrini F, O’Grady K, Hyvönen M, Folta KM, Baraldi E (2020) Genomic structure and transcript analysis of the Rapid Alkalinization Factor (RALF) gene family during host-pathogen crosstalk in Fragaria vesca and Fragaria x ananassa strawberry. PLoS One. doi: 10.1371/journal.pone.0226448 Open Access

Marko Hyvönen working at the University of Cambridge is a co-author on this Italian-US collaboration led by Francesca Negrini. This work describes the genomic organisation of the family of the Rapid Alkalinization Factors (RALFs) in octoploid strawberry. In addition they describe the upregulation of one family member, FanRALF3-1, during fungal infection. This will lead to future research aimed at defining the precise molecular relationship between FanRALF3-1 expression and the immune response in strawberry.

GARNet Research Roundup: February 18th 2020

by Geraint

Categories: Aberystwyth University, Cambridge University, Global, John Innes Centre, Rothamsted Research, Sainsbury Lab, Uncategorized, University of Birmingham, University of Cambridge, University of Oxford

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Published on: February 18, 2020

This weeks GARNet Research Roundup begins with two studies that characterize the role of proteins that are involved in the control of meiotic recombination. The first study is from the Henderson lab at the University of Cambridge and investigates the role of the REC8 protein whilst the second is from John Doonan’s group at Aberystwyth University and investigates the role of the cyclin-dependent kinase CDKG.

The third paper is from the same research group in Aberystwyth and investigates how alternative splicing can impact the function of the FLOWERING LOCUS M gene.

The next papers is a cross-UK collaboration led from Rothamsted Research and the John Innes Centre that identifies an important QTL associated with the generation of high-fibre wheat. The fifth paper is from the JIC and reveals how the immune resistance gene MLO plays a role in a plants association with beneficial microbial symbiotes.

The sixth paper is from the Gibbs lab at the University of Birmingham and further characterizes the function of the VRN2 component of the polycomb repressive complex 2.

Nick Harberd from Oxford is a corresponding author of the next paper, which identifies a new gene that could be used to improve nitrogen-use efficiency in rice.

The eighth paper is a proteomic-based study from the University of Cambridge that identifies novel stress-induced components of the Arabidopsis spliceosome.

The penultimate paper is from Jonathan Jones’ lab at the Sainsbury lab, Norwich in which they characterize a new transgenic line useful for studying the plant immune response.

The final paper includes Liam Dolan from Oxford as a co-author in a study that characterizes a novel ATPase from the algae Chara australis.

Lambing C, Tock AJ, Topp SD, Choi K, Kuo PC, Zhao X, Osman K, Higgins J, Franklin FCH, Henderson IR (2020) Interacting genomic landscapes of REC8-cohesin, chromatin and meiotic recombination in Arabidopsis thaliana. Plant Cell. doi: 10.1105/tpc.19.00866
Open Access

This study is led by Chris Lambing from Ian Henderson’s group at the University of Cambridge and includes collaborators from Leicester and Birmingham. They use ChIP-seq to identify the genomic regions associated with the REC8 protein, showing that it interacts with regions with multiple distinct chromatin states. This interaction plays a key role in controlling the formation of double strands breaks and is required to organize meiotic chromosome architecture and interhomolog recombination.

http://www.plantcell.org/content/early/2020/02/05/tpc.19.00866.long

Nibau C, Lloyd AH, Dadarou D, Betekhtin A, Tsilimigka F, Phillips DW, Doonan JH (2020) CDKG1 Is Required for Meiotic and Somatic Recombination Intermediate Processing in Arabidopsis. Plant Cell. doi: 10.1105/tpc.19.00942 Open Access

Candida Nibau from Aberystwyth University leads this research that reveals a critical role for the cyclin-dependent kinase G1 (CDKG) in the control of recombination, both during meiosis and within somatic cells. The authors discover that this role occurs early in the process through the stabilization of recombination intermediates.

http://www.plantcell.org/content/early/2020/02/10/tpc.19.00942

Nibau C, Gallemí M, Dadarou D, Doonan JH, Cavallari N (2020) Thermo-Sensitive Alternative Splicing of FLOWERING LOCUS M Is Modulated by Cyclin-Dependent Kinase G2. Front Plant Sci. doi: 10.3389/fpls.2019.01680 Open Access

Candida Nibau is first author on this collaboration between researchers in the UK (Aberystwyth University) and Vienna, Austria. They assess the factors that control the contribution of two splicing variants of the FLOWERING LOCUS M gene on flowering time across a temperature range. They find that this process is controlled by the activity of the cyclin-dependent kinase G2 (CDKG2) and its cognate cyclin, CYCLIN L1 (CYCL1).

https://www.frontiersin.org/articles/10.3389/fpls.2019.01680/full

Lovegrove A, Wingen LU, Plummer A, Wood A, Passmore D, Kosik O, Freeman J, Mitchell RAC, Hassall K, Ulker M, Tremmel-Bede K, Rakszegi M, Bedő Z, Perretant MR, Charmet G, Pont C, Salse J, Waite ML, Orford S, Burridge A, Pellny TK, Shewry PR, Griffiths S (2020) Identification of a major QTL and associated molecular marker for high arabinoxylan fibre in white wheat flour. PLoS One. doi: 10.1371/journal.pone.0227826
Open Access

Alison Lovegrove at Rothamsted Research is the first author on this cross-UK research that has gained significant interest from the main–stream media. Through analysis of a Chinese wheat variety with high dietary fibre due to the high amounts of cell wall polysaccharide arabinoxylan the authors identified a QTL that is responsible for this phenotype. Understanding this QTL will allow use of both marker-assisted breeding and new breeding technologies to aid in the generation of high yield, high fibre varieties.

Jacott CN, Charpentier M, Murray JD, Ridout CJ (2020) Mildew Locus O facilitates colonization by arbuscular mycorrhizal fungi in angiosperms. New Phytol. doi: 10.1111/nph.16465

Catherine Jacott is first author on this study from the JIC that investigates the role of the known barley resistance gene Mildew Resistance Locus O (MLO) during arbuscular mycorrhizal interactions in wheat, barley and Medicago. They show that MLO is important for this beneficial symbiotic association and that the role of MLO has been appropriated during infection with pathogenic powdery mildew.

https://nph.onlinelibrary.wiley.com/doi/abs/10.1111/nph.16465

Labandera AM, Tedds HM, Bailey M, Sprigg C, Etherington RD, Akintewe O, Kalleechurn G, Holdsworth MJ, Gibbs DJ (2020) The PRT6 N-degron pathway restricts VERNALIZATION 2 to endogenous hypoxic niches to modulate plant development. New Phytol. doi: 10.1111/nph.16477

Anne-Marie Labandera is first author on this work from Dan Gibbs’ lab in Birmingham. They show that ubiquitin-mediated proteolysis of the VERNALIZATION2 (VRN2) protein via the oxygen-dependent PRT6 N-degron pathway is important for many areas of plant development. This regulation of VRN2 has different developmental outcomes depending on whether it occurs in or out of meristematic tissues.

Wu K, Wang S, Song W, Zhang J, Wang Y, Liu Q, Yu J, Ye Y, Li S, Chen J, Zhao Y, Wang J, Wu X, Wang M, Zhang Y, Liu B, Wu Y, Harberd NP, Fu X (2020) Enhanced sustainable green revolution yield via nitrogen-responsive chromatin modulation in rice. Science. doi: 10.1126/science.aaz2046

Kun Wu is first author on this Chinese-led investigation that also includes Nick Harberd from Oxford University as a corresponding author. Working in rice they link genomic-wide chromatin changes with expression of the NGR5 (NITROGEN-MEDIATED TILLER GROWTH RESPONSE 5) transcription factor during nitrogen-induced growth. Overexpression of NGR5 can uncouple nitrogen-sensing from tiller production and therefore provide a novel tool to possibly enhance agricultural production in low nitrogen conditions.

https://science.sciencemag.org/content/367/6478/eaaz2046.long

Marondedze C, Thomas L, Lilley KS, Gehring C (2020) Drought Stress Causes Specific Changes to the Spliceosome and Stress Granule Components. Front Mol Biosci. doi: 10.3389/fmolb.2019.00163 Open Access

Claudius Marondedze is the first author on this collaboration between the University of Cambridge and KAUST in Saudi Arabia. They perform label-free mRNA interactome-capture to identify RNA interacting proteins that are induced after drought stress. This reveals over 40 novel spliceosome-interacting proteins but also 32 proteins that associate with stress granules, which are indicative of transcriptional arrest. This provides new insights into how plant stress responses might be altered by the activity of spliceosome components.

https://www.frontiersin.org/articles/10.3389/fmolb.2019.00163/full

Ngou BPM, Ahn HK, Ding P, Redkar A, Brown H, Ma Y, Youles M, Tomlinson L, Jones JDG (2020) Estradiol-inducible AvrRps4 expression reveals distinct properties of TIR-NLR-mediated effector-triggered immunity. J Exp Bot. doi: 10.1093/jxb/erz571

This research from Jonathan Jones’ group at the Sainsbury Lab, Norwich is led by Bruno Pok Man Ngou. They have developed a transgenic line that enables the transient in planta expression of AvrRps4, which is a potent bacterial immune effector. This stimulates the RRS1/RPS4-dependent immune response and provides insights into certain mechanisms of this pathway without exposing the plants to pathogens.

Zhang S, Habets M, Breuninger H, Dolan L, Offringa R, van Duijn B (2020) Evolutionary and Functional Analysis of a Chara Plasma Membrane H(+)-ATPase. Front Plant Sci. doi: 10.3389/fpls.2019.01707 Open Access

Liam Dolan from the University of Oxford is a co-author on this Dutch-led research that includes Sutun Zhang as first author. They characterize a plasma membrane localised ATPase from the algae Chara australis and perform complementation studies in both yeast and Arabidopsis. These studies allow the authors to propose that the mode of regulation of this algal ATPase is likely different from that of known yeast and land plant PM H+-ATPases.

GARNet Research Roundup: Jan 11th 2019

by Geraint

Categories: Bristol University, Cardiff University, epigenetics, Global, John Innes Centre, Nottingham University, Oxford University, Plos One, RHUL, Sainsbury Lab, Uncategorized, University of Birmingham, University of Bristol, University of Oxford, University of Sheffield

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Published on: January 11, 2019

The inaugural GARNet Research Roundup of 2019 firstly includes a paper from the University of Sheffield that has identified new pericentromeric epigenetic loci that affect the pathogen response. Secondly is a collaboration between researchers in Birmingham, Nottingham and Oxford that has identified a new mode of regulation of the VRN2 protein. Next are two papers from Jonathan Jones’ lab at The Sainsbury Laboratory in Norwich that firstly provides a toolkit for gene editing in Arabidopsis and secondly characterise the role of the NRG1 gene in the defense response. The penultimate paper is from Paul Devlin’s lab at RHUL and investigates the role of the circadian clock in the control of leaf overtopping whilst the final paper is a meeting report from a recent GARNet workshop on gene editing.

Furci L, Jain R, Stassen J, Berkowitz O, Whelan J, Roquis D, Baillet V, Colot V, Johannes F, Ton J (2019) Identification and characterisation of hypomethylated DNA loci controlling quantitative resistance in Arabidopsis. Elife. doi: 10.7554/eLife.40655.

Open Access

Leonardo Furci and Ritushree Jain are the lead authors on this study conducted at the University of Sheffield. The authors used a population of epigenetic recombinant inbred lines (epiRILs) to screen for resistance to the oomycete pathogen Hyaloperonospora arabidopsidis. These lines each share genetic information but have varied epigenetic changes. This analysis enabled the identification of plants with hypomethylated pericentromeric regions that were primed to better respond to the presence of this pathogen. The authors discuss the mechanism through which this might affect the defence response albeit without altering other aspects of plant growth.

https://elifesciences.org/articles/40655

Gibbs DJ, Tedds HM, Labandera AM, Bailey M, White MD, Hartman S, Sprigg C, Mogg SL, Osborne R, Dambire C, Boeckx T, Paling Z, Voesenek LACJ, Flashman E, Holdsworth MJ (2018) Oxygen-dependent proteolysis regulates the stability of angiosperm polycomb repressive complex 2 subunit VERNALIZATION 2. Nat Commun. doi: 10.1038/s41467-018-07875-7

Open Access

This collaboration between the Universities of Birmingham, Nottingham, Oxford and colleagues in Utrecht is led by Daniel Gibbs. They demonstrate that the amount of VRN2 protein, which is a member of the Polycomb Repressive Complex2, is controlled by the N-end rule pathway and that this regulation responses to both cold and hypoxia stress. Whilst the VRN2 gene is expressed throughout the plant, the N-end rule degradation pathway ensures that the protein is restricted to meristematic regions until the plant senses the appropriate abiotic stress. Classically VRN2 has been linked to the regulation of flowering time by altering gene expression at the FLC locus so this study introduces new complexity into this process through the involvement of the N-end rule pathway. More information on this linkage will undoubtedly follow over the coming years.

https://www.nature.com/articles/s41467-018-07875-7

Daniel kindly discusses this paper on the GARNet YouTube channel.

Castel B, Tomlinson L, Locci F, Yang Y, Jones JDG (2019) Optimization of T-DNA architecture for Cas9-mediated mutagenesis in Arabidopsis. PLoS One. doi: 10.1371/journal.pone.0204778

Open Access

Baptiste Castel is lead author of this work conducted at the Sainsbury Laboratory, Norwich in Jonathan Jones’ group. They have conducted a detailed analysis of the factors that contribute to successful gene editing by CRISPR-Cas9, specifically in Arabidopsis. This includes assessing the efficacy of different promotor sequences, guideRNAs, versions of Cas9 enzyme and associated regulatory sequences in the editing of a specific locus. Given that researchers are finding that different plants have different requirements when it comes to successful gene editing, this type of analysis will be invaluable for anyone who plans to conduct a gene editing experiment in Arabidopsis.

https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0204778

Castel B, Ngou PM, Cevik V, Redkar A, Kim DS, Yang Y, Ding P, Jones JDG (2018) Diverse NLR immune receptors activate defence via the RPW8-NLR NRG1. New Phytol. doi: 10.1111/nph.15659

In this second paper led by Baptiste Castel, they used the techniques outlined in the paper above to generate a set of CRISPR mutants deficient in NRG1, which is a RPW8-NLR resistance (R) gene. These nrg1 mutants have compromised signalling in all tested downstream TIR-NLR resistance genes. In addition the authors demonstrate that this signalling is needed for resistance to oomycete but not bacterial infection. Therefore this study reveals some significant details regarding the components of the disease response that are influenced by the activity of NRG1.

Woodley Of Menie MA, Pawlik P, Webb MT, Bruce KD, Devlin PF (2018) Circadian leaf movements facilitate overtopping of neighbors. Prog Biophys Mol Biol. doi: 10.1016/j.pbiomolbio.2018.12.012

This work is led by Michael Woodley Of Menie from Paul Devlin’s lab at Royal Holloway College and investigates the role of circadian leaf movements during shade avoidance and overtopping. Arabidopsis plants were grow in a grid system that meant leaves would interact with their neighbours and the authors show that plants with a normal circadian rhythm gained an advantage over those adapted to a longer period in which they were grown. This overtopping was additive to the advantage gained through shade avoidance and overall this paper shows that maintainance of clock-aligned leaf movements are beneficial to growth.

Parry G, Harrison CJ (2019) GARNet gene editing workshop. New Phytol. doi: 10.1111/nph.15573

Open Access

GARNet advisory committee member Jill Harrison and GARNet coordinator Geraint Parry are authors on this meeting report resulting from a GARNet organised workshop on gene editing that took place in March 2018 at the University of Bristol. Coincidentally part of the paper discusses the work that was presented at the meeting by Baptiste Castel, which is published in the paper described above.

GARNet Research Roundup: December 7th 2018

by Geraint

Categories: Aberystwyth University, Global, John Innes Centre, Lancaster University, Nottingham University, Rothamsted Research, Sainsbury Lab, SLCU, University of Birmingham, University of Bristol, University of Sheffield

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Published on: December 7, 2018

The first four papers in this GARNet Research Roundup includes research from Norwich Research Park. Firstly members of Jonathan Jones’ lab have identified a new Avr gene from Hyaloperonospora arabidopsidis. Secondly Anne Osbourn’s lab characterises two novel arabinosyltransferases that are involved in the plant defence response. Thirdly Cathie Martin’s group is involved in a study that investigates the biosynthesis of the metabolite ubiquinone. Finally in research from NRP is from Silke Robatzek’s lab, where they use a novel quantitative imaging system to characterise stomatal mutants.

The next two papers arise from work at SLCU, firstly looking at the possible role of a novel transposon family during gene-shuffling and secondly a paper that investigates the structure of an important component of the strigolactone signaling pathway.

The seventh paper from Peter Eastmond’s lab at Rothamsted Research identifies a novel gene involved in seed oil composition. The penultimate paper is from Peter Unwin at the University of Leeds and assesses the cell wall composition of ‘giant’ root cells induced by nematode Meloidogyne spp. Finally is a methods paper that describes how microCT imaging can be used to measure different leaf parameters.

Asai S, Furzer O, Cavik V, Kim DS, Ishaque N, Goritschnig S, Staskawicz B, Shirasu K, Jones JDG (2018) A downy mildew effector evades recognition by polymorphism of expression and subcellular localization. Nature Communications doi: 10.1038/s41467-018-07469-3

https://www.nature.com/articles/s41467-018-07469-3

Open Access

Shuta Asai from Jonathan Jones’ lab at The Sainsbury Lab, Norwich is the lead-author on this study that looks at co-evolution of host and pathogen resistance genes. The relationship between Hyaloperonospora arabidopsidis (Hpa) and Arabidopsis is defined by the gene-for-gene model of host Resistance (R) genes and pathogen Avirulence (AVR) genes. In this study the authors identify the HaRxL103Emoy2 AVR gene that is recognised by the R gene RPP4 and how this resistance is broken by altered expression or cellular localization.

Louveau T, Orme A, Pfalzgraf H, Stephenson M, Melton RE, Saalbach G, Hemmings AM, Leveau A, Rejzek M, Vickerstaff RJ, Langdon T, Field R, Osbourn AE (2018) Analysis of two new arabinosyltransferases belonging to the carbohydrate-active enzyme (CAZY) glycosyl transferase family 1 provides insights into disease resistance and sugar donor specificity. Plant Cell. doi: 10.1105/tpc.18.00641

Open Access

This research from the John Innes Centre, East Maling and Aberystwyth University is led by Thomas Louveau and Anne Osbourn and characterises two new arabinosyltransferases from oat and soybean. These enzymes are involved in the production of saponins that are involved in defence responses. These enzymes normally transfer arabinose to their substrates but through targeted mutations the authors modified one of them to instead transfer glucose. This study provides insights into the specifics of ‘sugar-donation’ and has identified potential novel targets for manipulating defence responses in two crop species.

Soubeyrand E, Johnson TS, Latimer S, Block A, Kim J, Colquhoun TA, Butelli E, Martin C, Wilson MA, Basset G (2018) The Peroxidative Cleavage of Kaempferol Contributes to the Biosynthesis of the Benzenoid Moiety of Ubiquinone in Plants. Plant Cell. 2018 Nov 14. pii: tpc.00688.2018. doi: 10.1105/tpc.18.00688

Open Access

This US-led study includes members of Cathie Martin’s lab at the John Innes Centre as co-authors in which they investigate the flavonoid-biosynthesis pathway, in particular the land-plant-specific synthesis of ubiquinone. They used Arabidopsis and tomato mutants to dissect the ubiquinone biosynthesis pathway, revealing that the B-ring of the specalised metabolite kaempferol is incorporated into the primary metabolite ubiquinone.

Bourdais G, McLachlan DH, Rickett LM, Zhou J, Siwoszek A, Häweker H, Hartley M, Kuhn H, Morris RJ, MacLean D, Robatzek S (2018) The use of quantitative imaging to investigate regulators of membrane trafficking in Arabidopsis stomatal closure. Traffic. doi: 10.1111/tra.12625

This work from both Norwich Research Park and the University of Bristol is led by Gildas Bourdais and describes a high-throughput quantitative imaging, reverse genetic screen to characterize known stomatal mutants on the basis of their effect on the endomembrane system. This screen allowed them to precisely define the point in the signaling pathway at which each mutant was affected, providing a genetic framework for the control of stomatal closure. This image-based tool should be a valuable addition to future studies that aim to use quantitative image analysis.

https://academic.oup.com/nar/advance-article/doi/10.1093/nar/gky1196/5198529

Catoni M, Jonesman T, Cerruti E, Paszkowski J (2018) Mobilization of Pack-CACTA transposons in Arabidopsis suggests the mechanism of gene shuffling (2018) Nucleic Acids Res. doi: 10.1093/nar/gky1196

Open Access

This work was performed at SLCU in Jerzy Paszkowski’s lab by current University of Birmingham lecturer Marco Catoni and analyses the genomic impact of the mobilisation of Pack-TYPE transposons. They track the movement of these transposons over multiple generations, showing that they can insert into genic regions and that their subsequent incomplete excisions can cause deleterious effect on gene function. Over evolutionary time the action of this type of mobile element might therefore importantly influence gene shuffling.

Shabek N, Ticchiarelli F, Mao H, Hinds TR, Leyser O, Zheng N (2018) Structural plasticity of D3-D14 ubiquitin ligase in strigolactone signalling. Nature. doi: 10.1038/s41586-018-0743-5

Nitzan Shabek is the lead author on his US-led paper that includes Fabrizio Ticchiarelli and Ottoline Leyser from SLCU as co-authors. This paper reveals the structure of the interaction between the Arabidopsis α/β hydrolase D14 and the D3 F-box protein, which is important for multiple aspects of strigolactone signaling. They show that structural plasticity of the D3 C-terminal α-helix, which can switch between two different forms, enables the interaction between D14 and the D53 repressor protein. Providing insight into these specific interactions is key to increasing understanding of how the D14-D3 complex influences strigolactone signaling.

Menard GN, Bryant FM, Kelly AA, Craddock CP, Lavagi I, Hassani-Pak K, Kurup S, Eastmond PJ (2018) Natural variation in acyl editing is a determinant of seed storage oil composition. Sci Rep. doi: 10.1038/s41598-018-35136-6

Open Access

This work is led from Rothamsted Research with Guillaume Menard as first author and uses the Arabidopsis MAGIC population to identify novel genetic loci involved in seed oil composition. They identified multiple QTLs associated with the quantity of the major very long chain fatty acid species 11-eicosenoic acid (20:1), showing that the enzyme LYSOPHOSPHATIDYLCHOLINE ACYLTRANSFERASE 2 (LPCAT2), which is involved in the acyl-editing pathway, was the primary QTL. Subsequently they show LPCAT2 expression was key for varying seed 20:1 content and that natural variation in the capacity for acyl editing is an important determinant of oil content.

Bozbuga R, Lilley CJ, Knox JP, Urwin PE (2018) Host-specific signatures of the cell wall changes induced by the plant parasitic nematode, Meloidogyne incognita (2018). Sci Rep. doi: 10.1038/s41598-018-35529-7

https://www.nature.com/articles/s41598-018-35529-7

Open Access

Refik Bozbuga at the University of Leeds is first author on this study that investigates the cell wall composition of nutrient-supplying ‘giant cells’ that are induced in roots following infection with Meloidogyne spp nematodes. They analysed the cell walls of giant cells from three species (Arabidopsis, maize and aduki bean) as well as using a set of Arabidopsis mutants to characterise the possible cell wall components that might influence infection rates.

Mathers AW, Hepworth C, Baillie AL, Sloan J, Jones H, Lundgren M, Fleming AJ, Mooney SJ, Sturrock CJ (2018) Investigating the microstructure of plant leaves in 3D with lab-based X-ray computed tomography. Plant Methods. doi: 10.1186/s13007-018-0367-7

Open Access
This paper from the Universities of Nottingham, Sheffield and Lancaster provides a methodology that uses a microCT image pipeline to measure leaf intercellular airspace and to provide quantitative data on descriptors of leaf cellular architecture. They measured 6 different plant species, showing that this 3D method generates an improved dataset when compared to traditional 2D methods of measurement.

https://plantmethods.biomedcentral.com/articles/10.1186/s13007-018-0367-7

GARNet Research Roundup: November 1st 2018

by Geraint

Categories: Bristol University, Glasgow University, Global, James Hutton Institute, John Innes Centre, Oxford University, Sainsbury Lab, Uncategorized, University of Bristol, University of Leeds, University of Manchester, University of York, Warwick University

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Published on: November 1, 2018

This week’s GARNet research roundup again features papers on a variety of topics. First is work from the University of Leeds that investigates the physical properties of callose:cellulose hydrogels and the implication for cell wall formation. Second is work from the University of York that assesses the role of the HSP90.2 protein in control of the circadian clock. The third paper features GARNet committee member Sarah McKim and looks at the genetic control of petal number whilst the next paper from the Universities of Warwick and Glasgow includes a proteomic analysis of different types of secretory vesicles.

The next two papers look at different aspects of hormone signaling. Firstly Alistair Hetherington from the University of Bristol is a co-author on a study that looks at the role of the BIG protein whilst Simon Turner’s lab in Manchester investigates the role of ABA in xylem fibre formation.

The penultimate paper includes Lindsey Turnbull from the University of Oxford and looks at the stability of epialleles across 5 generations of selection. Finally is a paper that includes researchers from TSL in Norwich who have contributed to a phosphoproteomic screen to identify phosphorylated amino acids that influence the defence response.

Abou-Saleh R, Hernandez-Gomez M, Amsbury S, Paniagua C, Bourdon M, Miyashima S, Helariutta Y, Fuller M, Budtova T, Connell SD, Ries ME, Benitez-Alfonso Y (2018) Interactions between callose and cellulose revealed through the analysis of biopolymer mixtures. Nature Communications DOI: 10.1038/s41467-018-06820-y

https://www.nature.com/articles/s41467-018-06820-y

Open Access
Radwa Abou-Saleh is lead author on this work from Yoselin Benitez-Alfonso’s lab at the University of Leeds. (1,3)-β-glucans such as callose play an important role in plant development yet their physical properties are largely unknown. This study analyses a set of callose:cellulose hydrogel mixtures as a proxy for different cell wall conditions. They show that callose:cellulose hydrogels are more elastic than those composed of only cellulose, providing evidence that the interactions between cellulose and callose are important for the structural features of cell walls.

Davis AM, Ronald J, Ma Z, Wilkinson AJ, Philippou K, Shindo T, Queitsch C, Davis SJ (2018) HSP90 Contributes To Entrainment of the Arabidopsis Circadian Clock via the Morning Loop. Genetics. doi: 10.1534/genetics.118.301586

http://www.genetics.org/content/early/2018/10/18/genetics.118.301586.long

Open Access
Amanda Davies is the first author on this study from Seth Davies’ lab at the University of York in which they assess the role of the molecular chaperone HSP90.2 on function of the circadian clock. The show hsp90.2-3 mutant plants have a lengthened circadian period with a specific defect in the morning. This data allows the authors to better understand the pathway through which HSP90.2 functions to entrain the circadian clock.

Monniaux M, Pieper B, McKim SM, Routier-Kierzkowska AL, Kierzkowski D, Smith RS, Hay A. The role of APETALA1 in petal number robustness. Elife. doi: 10.7554/eLife.39399

https://elifesciences.org/articles/39399

Open Access
GARNet committee member Sarah McKim is a co-author on this paper, that is led by Marie Monniaux, which includes research from her time at the University of Oxford. This work from the Hay lab in Cologne compares petal number in Arabidopsis thaliana, in which the number is invariant, and Cardamine hirsute, in which it varies. They show that petal number robustness can be attributed to the activity of the APETALA1 (AP1) floral regulator and that AP1 masks the activity of several genes in Arabidopsis but not in Cardamine.

Waghmare S, Lileikyte E, Karnik RA, Goodman JK, Blatt MR, Jones AME (2018) SNAREs SYNTAXIN OF PLANTS 121 (SYP121) and SYP122 mediate the secretion of distinct cargo subsets . Plant Physiol. doi: 10.1104/pp.18.00832

http://www.plantphysiol.org/content/early/2018/10/23/pp.18.00832.long

Open Access

This collaboration between the Universities of Glasgow and Warwick is led by Sakharam Waghmare, who works with Mike Blatt in Glasgow. This study uses proteomic approaches to characterise the secretory cargos within vesicles decorated with either of the SNARE proteins SYNTAXIN OF PLANTS 121 (SYP121) or SYP122. Genetic analysis suggests that SYP121 and SYP122 have redundant functions but this new research is able to identify cargo proteins that are either contained within both types of vesicle or that are specific to one or the other.

Zhang RX, Ge S, He J, Li S, Hao Y, Du H, Liu Z, Cheng R, Feng YQ, Xiong L, Li C, Hetherington AM, Liang YK (2018) BIG regulates stomatal immunity and jasmonate production in Arabidopsis. New Phytol. doi: 10.1111/nph.15568

Alistair Hetherington is a co-author on this China-based study led by Ruo‐Xi Zhang from Wuhan. This work adds to some recent interest in the BIG protein; in this study showing that it is involved in the interaction between JA and ethylene signaling during stress responses. In a complex set of interactions they show that the BIG protein differently alters opposing arms of the JA signaling pathway providing additional evidence that this protein is a key regulator of plant hormone signaling, albeit by a set of as yet unknown mechanisms.

Campbell L, Etchells JP, Cooper M, Kumar M, Turner SR. An essential role for Abscisic acid in the regulation of xylem fibre differentiation. Development. doi: 10.1242/dev.161992

This work from Simon Turner’s lab at the University of Manchester is led by Liam Campbell and identifies a novel role for ABA in the formation of xylem fibres during secondary thickening of the Arabidopsis hypocotyl. The action of ABA doesn’t alter the xylem:phloem ratio but rather the activity focuses on the formation of fibres within the already defined xylem tissue.

Schmid MW, Heichinger C, Coman Schmid D, Guthörl D, Gagliardini V, Bruggmann R, Aluri S, Aquino C, Schmid B, Turnbull LA, Grossniklaus U (2018) Contribution of epigenetic variation to adaptation in Arabidopsis. Nat Commun. doi: 10.1038/s41467-018-06932-5

https://www.nature.com/articles/s41467-018-06932-5

Open Access
Lindsey Turnbull (University of Oxford) is a co-author on this paper from Ueli Grossniklaus’ group in Zurich. Marc Schmid is lead author of the study that investigates the inheritance of Arabidopsis epialleles over 5 generations during conditions of simulated selection. The authors show that variations in methylation state are subject to selection and do indeed contribute to adaptive responses

Kadota Y, Liebrand TWH, Goto Y, Sklenar J, Derbyshire P, Menke FLH, Torres MA, Molina A, Zipfel C, Coaker G, Shirasu K (2018) Quantitative phosphoproteomic analysis reveals common regulatory mechanisms between effector- and PAMP-triggered immunity in plants. New Phytol. doi: 10.1111/nph.15523

Members of Cyril Zipfel’s group at The Sainsbury lab in Norwich are co-authors on this paper led by Yasuhiro Kadota from the RIKEN in Yokohama. They use a phosphoproteomic screen to identify a set of newly identified phosphorylation sites on membrane-associated proteins involved in effector-triggered immunity (ETI). Some of these phosphosites overlap with those known to be important for pathogen-associated molecular pattern (PAMP)-triggered immunity (PTI), indicating a convergence of signaling control of both these pathways to certain key residues.

GARNet Research Roundup: October 10th 2018

by Geraint

Categories: Edinburgh University, Global, John Innes Centre, Liverpool University, Sainsbury Lab, Uncategorized

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Published on: October 10, 2018

This edition of the GARNet research roundup begins with a paper from Jose Gutierrez-Marcos’ lab in Warwick that investigates the functional significance of inherited epigenetics marks in clonally propagated plants. Second is work from Sara Simonini and Lars Ostergaard (John Innes Centre) that defines a domain in the ETTIN protein important for the auxin response. Next is work from SLCU from Siobhan Braybrook and Henrik Jonsson that experimentally defines and models the role of cell wall composition in anisotropic hypocotyl growth. The fourth paper is from Jonathan Jones’ lab (TSL, Norwich) that adds to our understanding of the activity of the RRS1-R-RPS4 NLR immune complex.

The final three papers are each from the University of Edinburgh and look at different aspects of the relationship between light quality and the circadian clock. First is a paper from Karen Halliday’s lab that investigates the role of PHYA; next Andrew Millar is a co-author on a manuscript that looks at control of FT expression during seasonally realistic conditions. Finally Ference Nagy and Mirela Domijan (University of Liverpool) co-author a paper that assesses the role of HY5 in the response to blue-light.

Wibowo A, Becker C, Durr J, Price J, Spaepen S, Hilton S, Putra H, Papareddy R, Saintain Q, Harvey S, Bending GD, Schulze-Lefert P, Weigel D, Gutierrez-Marcos J (2018) Partial maintenance of organ-specific epigenetic marks during plant asexual reproduction leads to heritable phenotypic variation. Proc Natl Acad Sci U S A doi: 10.1073/pnas.1805371115

http://www.pnas.org/content/early/2018/09/06/1805371115.long

Open Access
Anjar Wibowo and Claude Becker are first authors on this UK-German collaboration from the labs of Jose Gutierrez-Marcos (University of Warwick) and Detlef Weigel (Max Planck Institutem, Tübingen). In this work they clonally propagate Arabidopsis and show that organ-specific epigenetic marks are maintained across generations. Interestingly these changes are then maintained through multiple rounds of sexual reproduction. These epigenetic marks provide heritable molecular and physiological phenotypes that can alter the response to pathogens, allowing progeny to maintain a beneficial epigenome that was generated in their parents.

Simonini S, Mas PJ, Mas CMVS, Østergaard L, Hart DJ (2018) Auxin sensing is a property of an unstructured domain in the Auxin Response Factor ETTIN of Arabidopsis thaliana. Sci Rep. doi: 10.1038/s41598-018-31634-9

https://www.nature.com/articles/s41598-018-31634-9

Open Access

This UK-France collaboration is led by Sara Simonini from the John Innes Centre and continues the Ostergaard lab’s work on the role of the auxin response factor ETTIN in the auxin response. In this paper they analyse the C-terminal ETT specific domain (ES domain) across plant lineages, showing that it does not directly bind auxin but could functional response to a dose response of auxin in a Y2H assay. Understanding more about this ES domain will increase our understanding of auxin sensing by ETTIN and more broadly about auxin-dependent gene regulation.

Bou Daher F, Chen Y, Bozorg B, Clough J, Jönsson H, Braybrook SA. Anisotropic growth is achieved through the additive mechanical effect of material anisotropy and elastic asymmetry. Elife. doi: 10.7554/eLife.38161

https://elifesciences.org/articles/38161

Open Access

Firas Bou Daher is the first author on work from Siobhan Braybrook’s lab conducted both in the Sainsbury Lab Cambridge University and at its new home in California. In this work they look at anisotropic growth in the Arabidopsis hypocotyl and the relationship between cellulose orientation and pectin deposition in the control of this process. They provide experimental evidence that growth parameters are influenced by pectin biochemistry in processes that begin immediately after germination.

Ma Y, Guo H, Hu L, Martinez PP, Moschou PN, Cevik V, Ding P, Duxbury Z, Sarris PF, Jones JDG (2018) Distinct modes of derepression of an Arabidopsis immune receptor complex by two different bacterial effectors. Proc Natl Acad Sci U S A. doi: 10.1073/pnas.1811858115

Yan Ma and Hailong Guo are lead authors on this study from Jonathan Jones’ lab at The Sainsbury Lab, Norwich. They perform a detailed examination of the RRS1-R-RPS4 NLR protein complex, which is necessary to respond to at the bacterial effectors, AvrRps4 and PopP2. Deletion of a WRKY transcription factor domain in the RRS1-R protein causes constitutive activation of the defense response, indicating that this domain maintains the complex in an inactive state in the absence of pathogens. Indeed AvrRps4 does interact with this WRKY domain but interestingly PopP2 activation requires interaction with a longer C-terminal extension of RRS1-R. This demonstrates that although these bacterial effectors are recognised by the same complex the interactions occurs in a subtly but functionally distinct ways.

Seaton DD, Toledo-Ortiz G, Ganpudi A, Kubota A, Imaizumi T, Halliday KJ (2018) Dawn and photoperiod sensing by phytochrome A. Proc Natl Acad Sci U S A. doi: 10.1073/pnas.1803398115

Open Access

This research from Karen Halliday’s lab in Edinburgh is led by Daniel Seaton and provided a detailed assessment of the role of phytochrome A (phyA) in photoperiod sensing, which is defined as the relationship between the circadian clock and external light signals. They show that PHYA activity, controlled by the transcription factors, PIF4 and PIF5, is a key regulator of morning activity, particularly in short photoperiods. PHYA protein accumulates during the night and responds to light by promoting a burst of gene expression that prepares the plant for the upcoming daylight and places this light receptor as a key detector of dawn.

Song YH, Kubota A, Kwon MS, Covington MF, Lee N, Taagen ER, Laboy Cintrón D, Hwang DY, Akiyama R, Hodge SK, Huang H, Nguyen NH, Nusinow DA, Millar AJ, Shimizu KK, Imaizumi T (2018) Molecular basis of flowering under natural long-day conditions in Arabidopsis. Nat Plants. doi: 10.1038/s41477-018-0253-3

Andrew Millar is a co-author on this US-led paper that investigates the circadian regulation of the Arabidopsis florigen gene FLOWERING LOCUS T (FT) within an annual context, showing that during the spring FT shows a morning peak is absent in their usual lab experiments. By adjusting growth-room conditions to mimic natural seasonal variations they show that phytochrome A and EARLY FLOWERING 3 regulate morning FT expression by stabilizing the CONSTANS protein. This manuscript highlights the importance of providing seasonal-specific conditions in order to understand field-relevant regulation of plant growth.

Hajdu A, Dobos O, Domijan M, Bálint B, Nagy I, Nagy F, Kozma-Bognár L. ELONGATED HYPOCOTYL 5 mediates blue light signalling to the Arabidopsis circadian clock (2018) Plant J. doi: 10.1111/tpj.14106

Ferenc Nagy (University of Edinburgh) is a co-author on this Hungarian-led study that looks the effect of light quality on the function of the key signaling hub transcription factor ELONGATED HYPOCOTYL 5 (HY5). They show that hy5 mutants show shorter period rhythms in blue but not in red light or darkness. Even though the pattern and level of HY5 alters its binding to downstream promotor elements, subsequent gene expression is only altered in a few genes. In collaboration with Mirela Domijan (University of Liverpool) https://www.liverpool.ac.uk/mathematical-sciences/staff/mirela-domijan/ they model this response to suggest that clock feedback mechanisms mask HY5-induced changes. Ultimately they show that HY5 is important in decoding the blue:red mix of white light and that it at least partially informs activity of the circadian oscillator.

Arabidopsis Research Roundup: February 12th

by Geraint

Categories: Cambridge University, Edinburgh University, Global, Nottingham University, Sainsbury Lab, sheffield university, SLCU, Uncategorized, University of Manchester, University of Sheffield

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Published on: February 12, 2018

This weeks Arabidopsis Research Roundup begins with a study from SLCU that investigates the interaction between nitrate and cytokinin signaling in the shoot meristem. Next is research from Sheffield that studies changes to the macromolecular composition of the photosynthetic apparatus following the transition from dark to light. Third are three papers that include University of Edinburgh faculty members as co-authors; Gary Loake is involved in a global study on NO signaling, Karen Halliday is included on a study into the relationship between clock components and the PIF-mediated hypocotyl elongation and Naomi Nakayama contributes to the development of a model that explains PIN protein localisation. Cyril Zipfel (TSL) is a co-author on the fifth paper, which introduces a new signaling component in the defence response and whilst the penultimate paper includes Denis Murphy (University of South Wales) and investigates the effect of dioxins on seed development. The final paper documents research from Manchester and Nottingham that uses a cress endosperm as a model to test the elastic properties of thin biological membranes.

Landrein B, Formosa-Jordan P, Malivert A,, Schuster C, Melnyk CW,, Yang W, Turnbull C, Meyerowitz EM, Locke JCW,, Jönsson H (2018) Nitrate modulates stem cell dynamics in Arabidopsis shoot meristems through cytokinins. PNAS doi: 10.1073/pnas.1718670115.

Open Access

http://www.pnas.org/content/early/2018/01/22/1718670115

Henrik Jonsson and James Locke (SLCU) are corresponding authors on this investigation into the relationship between nitrate and cytokinin signalling in the Arabidopsis shoot meristem (SAM). They show that nitrate availability determines the size of the SAM, which is controlled by the transport of cytokinin precursors from the root to the shoot. A discussion about this paper with lead author Benoit Landrien and Professor Jonsson is available on the GARNet YouTube and iTunes channels.

Wood WHJ, MacGregor-Chatwin C, Barnett SFH, Mayneord GE, Huang X, Hobbs JK, Hunter CN, Johnson MP (2018) Dynamic thylakoid stacking regulates the balance between linear and cyclic photosynthetic electron transfer. Nature Plants. doi: 10.1038/s41477-017-0092-7

Open with this link

This research in this manuscript has come from the University of Sheffield with Matthew Johnson as the corresponding author. They have used atomic force microscopy (AFM) to investigate how the transition from dark to light affects the macromolecular architecture of the photosynthetic apparatus within the thylakoid membrane. This transition does not alter the antenna size of either photosystem yet increases the number of thylakoid grana. Overall these changes serve to regulate the balance between light harvesting, CO2 fixation and enabling the protection of PSII activity from the destructive effects of non-photochemical quenching.

Imran QM, Hussain A, Lee SU, Mun BG, Falak N, Loake GJ, Yun BW (2018) Transcriptome profile of NO-induced Arabidopsis transcription factor genes suggests their putative regulatory role in multiple biological processes. Sci Rep. doi: 10.1038/s41598-017-18850-5.

https://www.nature.com/articles/s41598-017-18850-5

Open Access

Gary Loake (University of Edinburgh) is a contributor to this Korean-led manuscript that has performed expression analysis on plants treated with S-nitrosocysteine (CySNO). They have identified many novel NO-responsive transcription factors and were able to confirm the role of three random TFs in this response following analysis of loss of function mutants. This paper provides new insights into the molecular components that contribute to NO signalling during plant defence and immunity.

Martín G, Rovira A, Veciana N, Soy J, Toledo-Ortiz G, Gommers CMM, Boix M, Henriques R, Minguet EG, Alabadí D, Halliday KJ, Leivar P, Monte E Circadian Waves of Transcriptional Repression Shape PIF-Regulated Photoperiod-Responsive Growth in Arabidopsis. Curr Biol. doi: 10.1016/j.cub.2017.12.021

Karen Halliday (University of Ediburgh) is a co-author on this Spanish-led study that investigates how the expression of PHYTOCHROME-INTERACTING FACTORS (PIFs) genes is controlled. The activity of PIFs are responsible for determining the rate of hypocotyl elongation in different light conditions and this paper demonstrates that PSEUDO-RESPONSE REGULATORS PRR9/7/5 proteins act antagonistically to the PIFs by interacting at the promotor of the CDF5 transcription factor. This provides a mechanism to explain the circadian-controlled regulation of hypocotyl cell elongation.

Hernandez V, Barrio RA, Benítez M, Nakayama N, Romero-Arias JR, Villarreal Lujan C (2018) A physico-genetic module for the polarisation of auxin efflux carriers PIN-FORMED (PIN). Phys Biol. doi: 10.1088/1478-3975/aaac99

Naomi Nakayama (University of Edinburgh) is a co-author on this Mexican-led study that proposes a physico-genetic model that explains the localization of PIN auxin transporter proteins to the Arabidopsis plasma membrane. This model confirms experimental observations and allows the prediction that mechanical forces can predominate over molecular components.

www.cell.com/molecular-cell/fulltext/S1097-2765(17)30983-8

Wang J, Grubb LE, Wang J, Liang X, Li L, Gao C, Ma M, Feng F, Li M, Li L, Zhang X, Yu F, Xie Q, Chen S, Zipfel C, Monaghan J, Zhou JM (2018) A Regulatory Module Controlling Homeostasis of a Plant Immune Kinase. Mol Cell. doi: 10.1016/j.molcel.2017.12.026

This Chinese-led paper includes Cyril Zipfel (TSL) as a co-author and identifies the U-box proteins PUB25 and PUB26 as E3 ligases for the cytoplasmic kinase BIK1, which is a key rate limiting component of the plant defence response. This multi-protein regulatory module provides another level of complexity to our understanding of the molecular factors involved in plant immunity.

Hanano A, Almousally I, Shaban M, Murphy DJ (2018) Exposure of Arabidopsis Plants to Dioxin Results in a Wrinkled Seed Phenotype that is likely due to 20S Proteasomal Degradation of WRI1. J Exp Bot. doi: 10.1093/jxb/ery027

Denis Murphy (University of South Wales) is a co-author on this Syrian-led study that uses Arabidopsis seeds to test the negative effects of dioxins. Seeds treated with dioxins have a wrinked phenotype that corresponds to changes in the expression of genes related to lipid and carbohydrate metabolism. Overall this study reveals a novel set of genetic changes effects caused by dioxins that explain the profound effects on seed development.

S. P. Pearce, J. R. King, T. Steinbrecher, G. Leubner-Metzger, N. M. Everitt, M. J. Holdsworth (2018) Finite indentation of highly curved elastic shells Proceedings of the Royal Society A doi: 10.1098/rspa.2017.0482

Open Access

Plant scientist Mike Holdsworth (University of Nottingham) is a co-author on this paper that has used the endosperm from garden cress (Lepidium sativum) as the experimental model to define the elastic properties of a thin biological surface. Indentation experiments have been classically used to measure these properties and then develop mathematically models that explain their characteristics. These models rely on an assumed flat surface whereas in reality any surface will often be curved. By obtaining measurements from identations studies on the cress endosperm they are able to better refine the models that explain the properties of the membrane in this context.

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