GARNet Research Roundup: August 16th 2019

This holiday-time edition of the GARNet research roundup begins with two papers that include the late Ian Moore from the University of Oxford as a co-author. The first looks at the role of RAB-A5c in the control of cellular growth anisotropy whilst the second characterises the Transport Protein Particle II (TRAPPII) complex.

The third paper is a UK-wide collaboration that assesses the role of UVA signaling on stomatal development. Next is a paper from Cambridge and the JIC that has identified the TAF4b protein as a novel regulator of meiotic crossovers.

The fifth paper is from the University of York and characterizes a role for cis-12-oxo-phytodienoic acid (OPDA) during seed germination.

The next three papers feature scientists from the University of Leeds in research that investigates 1, a peroxisomal ABC transporter; 2, the role of LRR-RLKs in plasmodesmata development and 3, the cell wall characteristics of banana and mango fruit.

The ninth paper is from the University of Edinburgh and investigates the role of S-nitrosylation in the control of SUMO conjugation.

The next two papers include Steve Penfield at the JIC as a corresponding author; the first looks at the role of endosperm-expressed transcriptional factors during seed dormancy and the second, in collaboration with researchers at the University of Warwick, identifies novel QTLs involved in seed dormancy.

The penultimate study is from Lancaster and presents a surprising outcome resulting from the overexpression of the wheat CA1Pase gene. The final paper includes Alison Tidy and Zoe Wilson from University of Nottingham as co-authors on a study that looks at male fertility in Arabidopsis.


Kirchhelle C, Garcia-Gonzalez D, Irani NG, Jérusalem A, Moore I (2019) Two mechanisms regulate directional cell growth in Arabidopsis lateral roots. Elife. pii: e47988. doi: 10.7554/eLife.47988

Open Access

Charlotte Kirchhelle leads this work that was conducted in the lab of the late Ian Moore at the University of Oxford. She investigates the role of the plant-specific small GTPase RAB-A5c during growth anisotropy in lateral roots, which involves coordinated orientations of cellulose microfibrils (CMFs) and by cortical microtubules (CMTs). They identify RAB-A5c dependent and independent mechanisms to control cellular growth anisotropy in this growing tissue.

From https://elifesciences.org/articles/47988

Kalde M, Elliott L, Ravikumar R, Rybak K, Altmann M, Klaeger S, Wiese C, Abele M, Al B, Kalbfuß N, Qi X, Steiner A, Meng C, Zheng H, Kuster B, Falter-Braun P, Ludwig C, Moore I, Assaad FF (2019) Interactions between Transport Protein Particle (TRAPP) complexes and Rab GTPases in Arabidopsis. Plant J. doi: 10.1111/tpj.14442

This German-led study includes Monika Kalde from the University of Oxford as first author as well Ian Moore as co-author. They characterize the components and function of the Transport Protein Particle II (TRAPPII) complex. TRAPPII plays multiple roles in intra-cellular transport and this study identified 13 subunits, including several that were previously uncharacterised.


Isner JC, Olteanu VA, Hetherington AJ, Coupel-Ledru A, Sun P, Pridgeon AJ, Jones GS, Oates M, Williams TA, Maathuis FJM, Kift R, Webb AR, Gough J, Franklin KA, Hetherington AM (2019). Short- and Long-Term Effects of UVA on Arabidopsis Are Mediated by a Novel cGMP Phosphodiesterase. Curr Biol.29(15):2580-2585.e4. doi: 10.1016/j.cub.2019.06.071

Open Access

Jean-Charles Isner is the first author on this collaboration between labs in Bristol, York, Oxford and Cambridge. They show that UVA radiation (which represents 95% of the UV radiation reaching earth) inhibits stomatal opening through a process that involves a reduction in the cytosolic level of cGMP. The AtCN-PDE1 gene (a cGMP-activated phosphodiesterase) is needed to decrease cGMP levels in Arabidopsis. This response is present across the tree of life except in metazoans. They show AtCN-PDE1 is needed for the UVA response and that prolonged UVA exposure causes increased growth yet reduced water use efficiency.


Lawrence EJ, Gao H, Tock AJ, Lambing C, Blackwell AR, Feng X, Henderson IR (2019) Natural Variation in TBP-ASSOCIATED FACTOR 4b Controls Meiotic Crossover and Germline Transcription in Arabidopsis. Curr Biol. pii: S0960-9822(19)30844-9. doi: 10.1016/j.cub.2019.06.084

Open Access

This work from Ian Henderson’s lab in Cambridge and Xiaoqi Feng’s lab at the JIC is led by Emma Lawrence and isolates a novel modifier of meiotic crossover frequency, TBP-ASSOCIATED FACTOR 4b (TAF4b), which encodes a subunit of the RNA polymerase II general transcription factor TFIID. They show TAF4b expression is enriched in meiocytes, compared to the more general expression of its paralog TAF4. Ultimately they reveal TAF4b drives a novel mode of meiotic recombination control through its activity as a general transcription factor.


Barros-Galvão T, Dave A, Cole A, Harvey D, Langer S, Larson TR, Vaistij FE, Graham IA (2019) cis-12-oxo-phytodienoic acid represses Arabidopsis thaliana seed germination in shade light conditions. J Exp Bot. pii: erz337. doi: 10.1093/jxb/erz337

Open Access

Thiago Barros-Galvão is first author on this study from Ian Graham’s lab at the University of York. They investigate how the jasmonic acid pre-cursor cis-12-oxo-phytodienoic acid (OPDA) contributes to control of seed germination, particularly under shade conditions. OPDA acts through the activity of the transcription factor MOTHER-OF-FT-AND-TFL1 (MFT).

From https://academic.oup.com/jxb/advance-article/doi/10.1093/jxb/erz337/5536641

Carrier DJ, van Roermund CWT, Schaedler TA, Rong HL, IJlst L, Wanders RJA, Baldwin SA, Waterham HR, Theodoulou FL, Baker A (2019) Mutagenesis separates ATPase and thioesterase activities of the peroxisomal ABC transporter, Comatose. Sci Rep. 9(1):10502. doi: 10.1038/s41598-019-46685-9

Open Access

Alison Baker at the University of Leeds is the corresponding author of this UK, Dutch collaboration that includes David Carrier as first author. They characterise the peroxisomal ABC transporter, Comatose (CTS) through mutagenesis of key residues responsible for the proteins intrinsic acyl-CoA thioesterase (ACOT) activity. Ultimately they show that ACOT activity depends of endogenous ATPase activity but that these activities could be functional separated by mutagenesis of key residues.


Grison M, Kirk P, Brault M, Wu XN, Schulze WX, Benitez-Alfonso Y, Immel F, Bayer EMF (2019). Plasma membrane-associated receptor like kinases relocalize to plasmodesmata in response to osmotic stress. Plant Physiol. pii: pp.00473.2019. doi: 10.1104/pp.19.00473

Open Access

GARNet advisory committee member Yoselin Benitez-Alfonso and members of her research group are co-authors on the next two studies. This work is led by Magali Grison in Emmanuelle Bayer’s lab in Bordeaux. They show that the PM-localised Leucine-Rich-Repeat Receptor-Like-Kinases (LRR-RLKs), QSK1 and IMK2 relocate and cluster to the plasmodesmata under osmotic stress conditions. Through a variety of assays that focuses on QSK1 the authors show that reorganisation of RLKs can be important for the regulation of callose deposition at plasmodesmata and under osmotic stress this can have a functional effect on lateral root development.


Rongkaumpan G, Amsbury S, Andablo-Reyes E, Linford H, Connell S, Knox JP, Sarkar A, Benitez-Alfonso Y, Orfila C (2019) Cell Wall Polymer Composition and Spatial Distribution in Ripe Banana and Mango Fruit: Implications for Cell Adhesion and Texture Perception. Front Plant Sci. 10:858. doi: 10.3389/fpls.2019.00858

Open Access

Ganittha Rongkaumpan is first author on this interdisciplinary collaborative research from multiple departments at the University of Leeds. They characterise the composition of the cell wall in two fruits, banana and mango, which soften during ripening. The authors compared structural information, obtained using Atomic Force Microscopy and biochemical analysis, with data from rheology and tribology assays to understand why these fruits feel different in the mouth during ingestion.


Skelly MJ, Malik SI, Le Bihan T, Bo Y, Jiang J, Spoel SH, Loake GJ (2019) A role for S-nitrosylation of the SUMO-conjugating enzyme SCE1 in plant immunity Proc Natl Acad Sci U S A. pii: 201900052. doi: 10.1073/pnas.1900052116

Michael Skelly from the University of Edinburgh is the lead author of this study from the labs of Gary Loake and GARNet chairman Steven Spoel. They investigate the mechanism through which nitric oxide signaling after pathogen recognition stimulates inhibitory S-nitrosylation of the Arabidopsis SUMO E2 enzyme, SCE1. S-nitrosylation occurs on the evolutionary conserved Cys139 of SCE1 and they investigate the wider significant of this residue in the control of immune responses across eukaryotes.


MacGregor DR, Zhang N, Iwasaki M, Chen M, Dave A, Lopez-Molina L, Penfield S (2019) ICE1 and ZOU determine the depth of primary seed dormancy in Arabidopsis independently of their role in endosperm development. Plant J. 98(2):277-290. doi: 10.1111/tpj.14211

Open Access

Dana MacGregor (now at Rothamsted Research) leads this work from the lab of Steve Penfield at the JIC that investigates the extent of control on depth of primary dormancy that is mediated by the endosperm-expressed transcription factors ZHOUPI (ZOU) and INDUCER OF CBF EXPRESSION1 (ICE1). These effects are additive and independent of their role in endosperm development since the dormancy defect in ice1 and zou mutants can be ameliorated without altering seed morphology. They show that ICE1 acts primarily through control of ABA INSENSITIVE 3 (ABI3).


Footitt S, Walley PG, Lynn JR, Hambidge AJ, Penfield S, Finch-Savage WE (2019) Trait analysis reveals DOG1 determines initial depth of seed dormancy, but not changes during dormancy cycling that result in seedling emergence timing. New Phytol. doi: 10.1111/nph.16081

This research is a collaboration between the John Innes Centre and the Universities Liverpool and Warwick, from which Steven Footitt is first author. They used two Arabidopsis ecotypes that have differences in the timing of seedling emergence to identify new QTLs involved in depth of seed dormancy and Seedling Emergence Timing (SET). They revealed that DOG1 is important for determining depth of dormancy. In addition they identified three new SET QTLs, which are each physically close to DOG1, that play a role in the control of SET in the field.


Lobo AKM, Orr D, Gutierrez MO, Andralojc J, Sparks C, Parry MAJ, Carmo-Silva E (2019) Overexpression of ca1pase decreases Rubisco abundance and grain yield in wheat. Plant Physiol. pii: pp.00693.2019. doi: 10.1104/pp.19.00693

Open Access

This research from Lancaster Environmental Centre and their Brazilian collaborators is led by Ana Karla Lobo and demonstrates that overexpression of 2-carboxy-D-arabinitol-1-phosphate phosphatase (CA1Pase) in wheat causes a reduction in above ground biomass and compromises wheat grain yields. As CA1Pase is involved in removing inhibitors of Rubisco activity this result is contrary to the anticipated outcome. This suggests that Rubisco inhibitors might actually protect enzyme activity, thus maintaining the number of active sites that the enzyme is able to support.


Zhao SQ, Li WC, Zhang Y, Tidy AC, Wilson ZA (2019) Knockdown of Arabidopsis ROOT UVB SENSITIVE4 Disrupts Anther Dehiscence by Suppressing Secondary Thickening in the Endothecium. Plant Cell Physiol. doi: 10.1093/pcp/pcz127

Shu-Qing Zhao is the lead author on this China-UK collaboration that includes Alison Tidy and Zoe Wilson from the University of Nottingham. They show that using an artificial microRNA to reduce levels of the RUS4 gene in Arabidopsis causes a decline in male fertility. They perform a detailed analysis of the RUS4 expression module and how it impacts fertility.

GARNet Research Roundup: April 29th 2019

This edition of the GARNet research roundup features fundamental plant science research conducted in a range of experimental organisms. Firstly Liam Dolan’s lab in Oxford looks at the function of bHLHs proteins in cell differentiation across land plant evolution. Secondly Anthony Hall’s group at the Earlham Institute have identified a novel RecQ helicase involved in work exclusively conducted in wheat. Thirdly researchers from Nottingham work with Arabidopsis to characterise an EXPANSIN protein essential for lateral root development.

The fourth paper is the first of two that look at germination and uses a new model, Aethionema arabicum, to study the role of light in seed dormancy. This work includes research from Royal Holloway. The second ‘dormancy’ paper is from Peter Eastmond’s lab at Rothamsted and further characterises the DOG1 gene in Arabidopsis. The penultimate paper includes co-authors from Warwick and Leeds and introduces a novel chemical inhibitor of auxin transport. The final paper from researchers in Birmingham introduces the 3DCellAtlas Meristem, a powerful tool for cellular annotation of the shoot apical meristem.


Bonnot C, Hetherington AJ, Champion C, Breuninger H, Kelly S, Dolan L (2019) Neofunctionalisation of basic helix loop helix proteins occurred when embryophytes colonised the land. New Phytol. doi: 10.1111/nph.15829 https://nph.onlinelibrary.wiley.com/doi/abs/10.1111/nph.15829

Clemence Bonnot is lead author on this study from Liam Dolan’s lab at the University of Oxford in which the authors assess the role of ROOT HAIR DEFECTIVE SIX-LIKE (RSL) genes during evolution of plant development. They look at the function of a member of this bHLH transcription factor family called CbbHLHVIII identified in the charophyceaen alga Chara braunii. This gene is expressed at specific morphologically important regions in the algae and cannot rescue the function of related RSL genes in Marchantia or Arabidopsis. This suggests that the function of RSL proteins in cell differentiation has evolved by neofunctionalisation through land plant lineages.


Gardiner LJ, Wingen LU, Bailey P, Joynson R, Brabbs T, Wright J, Higgins JD, Hall N, Griffiths S, Clavijo BJ, Hall A (2019) Analysis of the recombination landscape of hexaploid bread wheat reveals genes controlling recombination and gene conversion frequency. Genome Biol. 20(1):69. doi: 10.1186/s13059-019-1675-6 https://genomebiology.biomedcentral.com/articles/10.1186/s13059-019-1675-6

Open Access

Laura Gardiner and Anthony Hall lead this work that was conducted at the Earlham Institute and uses a bespoke set of bioinformatic tools that allow fundamental questions to be asked in hexaploid wheat. They looked at crossover and gene conversion frequencies in 13 recombinant inbred mapping populations and were able to identity an important QTL and confirm functionality for a novel RecQ helicase gene. This gene does not exist in Arabidopsis and therefore this discovery-motivated research needed to be conducted in wheat. They hope that this identification will provide future opportunities to tackle the challenge of linkage drag when attempting to develop new crops varieties.


Ramakrishna P, Ruiz Duarte P, Rance GA, Schubert M, Vordermaier V, Vu LD, Murphy E, Vilches Barro A, Swarup K, Moirangthem K, Jørgensen B, van de Cotte B, Goh T, Lin Z, Voβ U, Beeckman T, Bennett MJ, Gevaert K, Maizel A, De Smet I (2019) EXPANSIN A1-mediated radial swelling of pericycle cells positions anticlinal cell divisions during lateral root initiation. Proc Natl Acad Sci U S A. 2019 Apr 3. pii: 201820882. doi: 10.1073/pnas.1820882116 https://www.pnas.org/content/early/2019/04/02/1820882116.long

Open Access

This pan-European study is led by Priya Ramakrishna at the University of Nottingham and includes co-authors from the UK, Belgium, Germany and Denmark. The authors look at the lateral root development and characterise the function of the EXPANSIN A1 protein. This protein influences the physical changes in the cell wall that are needed to enable the asymmetry cell divisions that define the location of a new lateral root. Plants lacking EXPA1 function do not properly form lateral roots and are unable to correctly respond to an inductive auxin signal. This clearly demonstrates an important requirement for the activity of genes that transmit cell signals into the physical relationships that exist between cells.

https://plantmethods.biomedcentral.com/articles/10.1186/s13007-019-0413-0

Mérai Z, Graeber K, Wilhelmsson P, Ullrich KK, Arshad W, Grosche C, Tarkowská D, Turečková V, Strnad M, Rensing SA, Leubner-Metzger G, Scheid OM (2019) Aethionema arabicum: a novel model plant to study the light control of seed germination. J Exp Bot. pii: erz146. doi: 10.1093/jxb/erz146

https://academic.oup.com/jxb/advance-article/doi/10.1093/jxb/erz146/5428144

Open Access

This paper includes authors from the UK, Germany, Austria and the Czech Republic including Kai Graeber and Gerhard Leubner-Metzger at Royal Holloway. They introduce the Brassica Aethionema arabicum as a new model to investigate the mechanism of germination inhibition by light as they have identified accessions that are either light-sensitive or light-neutral. In contrast germination in Arabidopsis is stimulated by light. Transcriptome analysis of Aethionema arabicum accessions reveal expression changes in key hormone-regulated genes. Overall they show that largely the same module of molecular components are involved in control of of seed dormancy irrespective of the effect of light on germination. Therefore any phenotypic changes likely result from changes in the activity organisms-specific of these genes.

https://academic.oup.com/jxb/advance-article/doi/10.1093/jxb/erz146/5428144

Bryant FM, Hughes D, Hassani-Pak K, Eastmond PJ (2019) Basic LEUCINE ZIPPER TRANSCRIPTION FACTOR 67 transactivates DELAY OF GERMINATION 1 to establish primary seed dormancy in Arabidopsis. Plant Cell. pii: tpc.00892.2018. doi: 10.1105/tpc.18.00892 http://www.plantcell.org/content/early/2019/04/08/tpc.18.00892.long

Open Access

http://www.plantcell.org/content/early/2019/04/08/tpc.18.00892.long

Fiona Bryant is lead author on this research from Rothamsted Research that investigates the factors that control expression of the DOG1 gene, which is a key regulator of seed dormancy. They show that LEUCINE ZIPPER TRANSCRIPTION FACTOR67 (bZIP67) regulates DOG1 expression and have uncovered a mechanism that describes the temperature-dependent regulation of DOG1 expression. Finally they identity a molecular change that explains known allelic difference in DOG1 function, which informs different levels of dormancy in different accessions.


Oochi A, Hajny J, Fukui K, Nakao Y, Gallei M, Quareshy M, Takahashi K, Kinoshita T, Harborough SR, Kepinski S, Kasahara H, Napier RM, Friml J, Hayashi KI (2019) Pinstatic acid promotes auxin transport by inhibiting PIN internalization. Plant Physiol. 2019 Apr 1. pii: pp.00201.2019. doi: 10.1104/pp.19.00201 http://www.plantphysiol.org/content/early/2019/04/01/pp.19.00201.long

Open Access

http://www.plantphysiol.org/content/early/2019/04/01/pp.19.00201.long

This Japanese-led study includes co-authors from the Universities of Warwick and Leeds and describes the identification of a novel positive chemical modulator of auxin cellular efflux. This aptly named PInStatic Acid (PISA) prevents PIN protein internalization yet does not impact the SCFTIR1/AFB signaling cascade. Therefore the authors hope that PISA will be a useful tool for unpicking the cellular mechanisms that control auxin transport.


Montenegro-Johnson T, Strauss S, Jackson MDB, Walker L, Smith RS, Bassel GW. (2019) 3D Cell Atlas Meristem: a tool for the global cellular annotation of shoot apical meristems. Plant Methods. 15:33. doi: 10.1186/s13007-019-0413-0

https://plantmethods.biomedcentral.com/articles/10.1186/s13007-019-0413-0

Open Access

Thomas Montenegro-Johnson, Soeren Strauss, Matthew Jackson and Liam Walker lead this methods paper that was prepared following research that took place at the University of Birmingham and the Max Planck Institute for Plant Breeding Research in Cologne. They describe the 3DCellAtlas Meristem, a tool allows the complete cellular annotation of cells within a shoot apical meristem (SAM), which they have successfully tested in both Arabidopsis and tomato. The authors state that ‘this provides a rapid and robust means to perform comprehensive cellular annotation of SAMs and digital single cell analyses, including cell geometry and gene expression’.

https://plantmethods.biomedcentral.com/articles/10.1186/s13007-019-0413-0

GARNet Research Roundup: December 7th 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: October 19th 2018

This edition of the GARNet research roundup includes six papers that look at different areas of plant biology. Firstly is a Belgian-led study with co-authors from Nottingham that introduces adaptive Xerobranching, a cereal-root response that can be mimicked in Arabidopsis by modulating ABA signaling. Second is study from Juriaan Ton’s lab in Sheffield that investigates the extent of DNA methylation during transgenerational acquired disease resistance. Third is paper from the John Innes Centre that places the DET1/COP1-PIF4 signaling module as a key determinant of the plants decision to allocate resources toward growth or defence.

The fourth paper is from Siobhan Braybrook’s (now ex-) lab at SLCU and provides an extensive dataset of the shape of leaf pavement cells across plant lineages. The penultimate paper is from a group at the University of Birmingham investigating the role of TOPII in the removal of damaging chromosome interlocks that occur during meiosis. The final paper returns to the ABA signalling with a study from Rothamsted Research that looks at the impact of the N-end rule on the different growth responses that occur during seed germination.


https://www.cell.com/current-biology/pdfExtended/S0960-9822(18)31004-2

Orman-Ligeza B, Morris EC, Parizot B, Lavigne T, Babé A, Ligeza A, Klein S, Sturrock C, Xuan W, Novák O, Ljung K, Fernandez MA, Rodriguez PL, Dodd IC, De Smet I, Chaumont F, Batoko H, Périlleux C, Lynch JP, Bennett MJ, Beeckman T, Draye X (2018) The Xerobranching Response Represses Lateral Root Formation When Roots Are Not in Contact with Water. Current Biology. doi: 10.1016/j.cub.2018.07.074

Open Access

Emily Morris and Beata Orman-Ligeza are co-authors on this Belgian-led study that includes authors from the Universities of Nottingham and Lancaster. They introduce a new adaptive response termed xerobranching that defines the repression of root branching when a root tip is not in contact with wet soil. This response occurs in cereal roots but can be mimicked in Arabidopsis by treatment with ABA as the authors show that the response is dependent on the PYR/PYL/RCAR-dependent signaling pathway. This response allows roots to respond to the realistically varied microclimate encountered through the soil and offers another excellent example of how using both cereals and Arabidopsis can provide answers that would not be possible from a single experimental system.


Stassen JHM, López A, Jain R, Pascual-Pardo D, Luna E, Smith LM, Ton J (2018) The relationship between transgenerational acquired resistance and global DNA methylation in Arabidopsis. Sci Rep. doi: 10.1038/s41598-018-32448-5

https://www.nature.com/articles/s41598-018-32448-5

Open Access

Joost Stassen and Ana Lopez are the lead authors of this study from Juriaan Ton’s lab in Sheffield that continues their work on mechanisms that explain transgenerational acquired resistance (TAR). TAR occurs in the progeny of heavily diseased plants and in this study they investigate the extent of DNA methylation in generations following exposure to pathogens. They find that the extent of TAR-induced methylation was in direct proportion to the number of previous generations that had been exposed to disease. The majority of this methylation was in the CG context in gene bodies and clearly shows that methylation is an important component of molecular changes that occur during TAR.


Gangappa SN, Kumar SV (2018) DET1 and COP1 Modulate the Coordination of Growth and Immunity in Response to Key Seasonal Signals in Arabidopsis. Cell Rep. doi: 10.1016/j.celrep.2018.08.096

https://www.cell.com/cell-reports/fulltext/S2211-1247(18)31415-3

Open Access

Sreeramaiah Gangappa performed this work with Vinod Kumar at the John Innes Centre in which they investigate the molecular pathways that regulate the environmental signals that feed into the balance decision between growth and defense responses. They show that De-Etiolated 1 (DET1) and Constitutive Photomorphogenic 1 (COP1) negatively regulate immunity during favourable growth conditions and that this response is coordinated through the PIF4 transcription factor. These findings lead the authors to conclude that the DET1/COP1-PIF4 module is a key determinant of the different growth requirements that are necessary to response to either environment and disease.


Vőfély RV, Gallagher J, Pisano GD, Bartlett M, Braybrook SA (2018) Of puzzles and pavements: a quantitative exploration of leaf epidermal cell shape. New Phytol. doi: 10.1111/nph.15461

Open Access

https://nph.onlinelibrary.wiley.com/doi/abs/10.1111/nph.15461

Work from Siobhan Braybrook’s lab features in the Research Roundup for the second consecutive edition, this time led by Roza Vofely at the Sainsbury Lab Cambridge University (SLCU). In this study they have investigated the shape of leaf epidermal pavement cells from a remarkable 278 plant taxa in order to ascertain whether certain lineages are characterized by different cell shapes and whether the presence of an undulating cell wall is common, as in both maize and Arabidopsis. Interestingly they found that these primary examples were the exception as strongly undulating cell walls were unusual. They found that different lineages were characterised by similar levels of undulation and the authors conclude that this study sets a quantitative benchmark on which future experiments can be based that aim to understand the underlying factors that control pavement cell shape.


Martinez-Garcia M, Schubert V, Osman K, Darbyshire A, Sanchez-Moran E, Franklin FCH (2018) TOPII and chromosome movement help remove interlocks between entangled chromosomes during meiosis. J Cell Biol. doi: 10.1083/jcb.201803019

Open Access
Marina Martinez‐Garcia is the lead author on this work conducted during her time working with Eugenio Sanchez-Moran and Chris Franklin at the University of Birmingham. Normal meiosis requires a lack of structural interlocks between entangled chromosomes that can result from inevitable collisions in an area so packed with nucleic acid. In this paper the authors confirm a previously developed hypothesis that topoisomerase II (TOPII) is needed to remove interlocks. However it is not the only determinant of the number of interlocks as in Arabidopsis mutants in which chromosome movement is reduced, interlocks occur irrespective of the presence of TOPII.


Zhang H, Gannon L, Jones PD, Rundle CA, Hassall KL, Gibbs DJ, Holdsworth MJ, Theodoulou FL (2018) Genetic interactions between ABA signalling and the Arg/N-end rule pathway during Arabidopsis seedling establishment. Sci Rep. doi: 10.1038/s41598-018-33630-5

https://www.nature.com/articles/s41598-018-33630-5

Open Access

Hongtao Zhang is the lead author of this work from the lab of Freddie Theodoulou at Rothamsted Research that investigates the role of the PROTEOLYSIS6 (PRT6) N-recognin E3 ligase in the ABA response. PRT6 regulated degradation of Group VII of the Ethylene Response Factor superfamily (ERFVIIs) controls both sugar sensitivity and oil body breakdown in germinating Arabidopsis seedlings. They found that the former but not the latter response was enhanced by ABA signaling components when the ERFVIIs were stabilised. The authors conclude that during seed germination the N-end rule controls multiple layers of regulation, both in an ABA dependent and independent manner

Arabidopsis Research Roundup: January 10th 2018

This Arabidopsis Research Roundup covers the final papers of 2017 and the first of this new year. The initial paper is led by researchers in Bristol and characterises how the multifaceted BIG protein influences stomatal dynamics in response to altered CO2. Second is a manuscript from SLCU that for the first time in plants demonstrates nuclear sequestration of cell cycle regulated mRNAs.

Next is a paper from Rothamsted that describes a role for the hormone GA during floral development. David Salt (Nottingham) is then a co-author on a manuscript that has determined a role for the CTL protein in ion homeostasis.

Seth Davies from York is the lead author on the next study that investigates a link between metabolism and the circadian clock. The sixth paper looks at genes involved in the control of autophagy and features Patrick Gallois (Manchester) as a co-author.

There are three papers from researchers working on Norwich Research Park with Cyril Zipfel (TSL) involved in a study that looks at vacuolar trafficking of BR signaling components. Janneke Balk leads a study that characterises enzymes involved in biosynthesis of metal co-factors whilst the final NRP-based paper from Nick Pullen and Steven Penfield (John Innes Centre) describes the Leaf-GP open software for automated plant phenotyping.

The penultimate paper uses a set of PlantProbes (developed by Paul Knox at Leeds) to study pollen development whilst the final paper from Keith Lindsey (Durham) describes the application of a Bayesian statistical methodology to model the parameters that control a hormone signaling network.


He J, Zhang RX, Peng K, Tagliavia C, Li S, Xue S, Liu A, Hu H,, Zhang J, Hubbard KE,, Held K, McAinsh MR, Gray JE, Kudla J, Schroeder JI, Liang YK, Hetherington AM (2018) The BIG protein distinguishes the process of CO2 -induced stomatal closure from the inhibition of stomatal opening by CO2. New Phytol. doi: 10.1111/nph.14957 Open Access

Alistair Hetherington (University of Bristol) leads this UK-USA-China collaboration that has characterised a role for the mysterious BIG protein during stomatal closure in response to altered CO2 concentration. Interestingly BIG mutants do not show a defect in stomatal opening in response to altered CO2, allowing the dissection of this complex response through the activity of this protein. It remains to be determined exactly how the BIG protein influences this process.


Yang W, Wightman R, Meyerowitz EM (2017) Cell Cycle Control by Nuclear Sequestration of CDC20 and CDH1 mRNA in Plant Stem Cells. Mol Cell. doi: 10.1016/j.molcel.2017.11.008

Elliott Meyerowitz (SLCU) is the corresponding author of this research that provides the first characterisation in plants of nuclear sequestration of mRNAs from developmental important genes. The authors show that Arabidopsis anaphase-promoting complex/cyclosome (APC/C) coactivator genes CDC20 and CCS52B are confined to the nucleus in prophase, preventing translation of the cognate proteins until metaphase, which appears to protect cyclins from degradation at an inappropriate phase of the cell cycle


Plackett ARG, Powers SJ, Phillips AL, Wilson ZA, Hedden P, Thomas SG4 (2017) The early inflorescence of Arabidopsis thaliana demonstrates positional effects in floral organ growth and meristem patterning. Plant Reprod. doi: 10.1007/s00497-017-0320-3

This study is led from Rothamsted Research and includes Zoe Wilson from the University of Nottingham. They perform a systematic analysis of early floral organ initiation across the Arabidopsis inflorescence, discovering that both GA-dependent and independent stages are important for this process, albeit via the activity of presently unknown factors.


Gao YQ, Chen JG, Chen ZR An D, Lv QY, Han ML, Wang YL, Salt DE, Chao DY (2017) A new vesicle trafficking regulator CTL1 plays a crucial role in ion homeostasis. PLoS Biol. doi: 10.1371/journal.pbio.2002978

Open Access

David Salt (University of Nottingham) is a co-author on this Chinese-led investigation into the role of the vesicle trafficking regulator choline transporter (CTL) during the control of ionome homeostasis. Using ctl1 mutants they show that this function is required for the action of certain ion transporters as well as during plasmodesmata (PD) development. This study provides novel insights into the role of vesicular transport in the control of ion homeostasis and how the location of these ions might alter vesicle activity.


Sánchez-Villarreal A, Davis AM, Davis SJ (2017) AKIN10 Activity as a Cellular Link Between Metabolism and Circadian-Clock Entrainment in Arabidopsis thaliana.

Plant Signal Behav. doi: 10.1080/15592324.2017.1411448

Seth Davies (University of York) is the corresponding author on this study demonstrating that overexpression of the AKIN10 subunit of the SnRK1 complex results in increased period length of the circadian clock. The authors postulate about the possible links between metabolic rate and function of the clock, allowing them to present a model of action that features each of the central regulatory elements.


Havé M, Balliau T, Cottyn-Boitte B, Dérond E, Cueff G, Soulay F, Lornac A, Reichman P, Dissmeyer N, Avice JC, Gallois P, Rajjou L, Zivy M, Masclaux-Daubresse C (2017) Increase of proteasome and papain-like cysteine protease activities in autophagy mutants: backup compensatory effect or pro cell-death effect? J Exp Bot. doi: 10.1093/jxb/erx482

Open Access
This study is led by French researchers and includes Patrick Gallois (University of Manchester) as a co-author. The work focuses on the role of the ATG genes during autophagy, the key process that controls nutrient recycling during senescence. In atg5 mutants they show that different sets of proteases are misregulated, suggestive of a complex relationship between the enzymes involved in nutrient remobilization.


Liu Q, Vain T, Viotti C, Doyle SM, Tarkowská D, Novák O, Zipfel C, Sitbon F, Robert S, Hofius D (2017) Vacuole Integrity Maintained by DUF300 Proteins Is Required for Brassinosteroid Signaling Regulation. Mol Plant. doi: 10.1016/j.molp.2017.12.015

Cyril Zipfel (TSL) is a member of this Pan-European consortium that investigates the role of the vacuolar proteins, LAZARUS1 (LAZ1) and LAZ1 HOMOLOG1 (LAZ1H1) on the cellular cycling of BR-signaling components. Plants with mutations in laz1 and laz1h1 show increased BAK1 accumulation at the tonoplast as well as enhanced BRI1 trafficking and degradation. These DUF300 proteins appear to play a specific role in BR signalling as other vacuolar-associated proteins are not involved in this process.


Kruse I, Maclean A, Hill L, Balk J (2017) Genetic dissection of cyclic pyranopterin monophosphate biosynthesis in plant mitochondria. Biochem J. doi: 10.1042/BCJ20170559 Open Access

Janneke Balk (John Innes Centre) leads this study that has identified novel alleles in mitochondrial enzymes that are involved in the biosynthesis of metal cofactors. Analysis of these enzyme mutant reveals that they show deficiencies in the synthesis of cyclic pyranopterin monophosphate (cPMP), revealing fresh insights into the metabolic processes involving this key intermediate.


Zhou J, Applegate C, Alonso AD, Reynolds D, Orford S, Mackiewicz M, Griffiths S, Penfield S, Pullen N (2017) Leaf-GP: an open and automated software application for measuring growth phenotypes for arabidopsis and wheat. Plant Methods. doi: 10.1186/s13007-017-0266-3

Open Access

Nick Pullen and Steve Penfield (John Innes Centre) introduce this new software tool for the automated measurement of plant phenotypes. This Leaf-GP software is open access and has the sophistication to discriminate between different aspects of both Arabidopsis and greenhouse growth wheat.

This paper is back of a special issue of Plant Methods that is based on the use of Computer Vision in Plant Phenotyping.


Ndinyanka Fabrice T, Vogler H, Draeger C, Munglani G, Gupta S, Herger AG, Knox JP, Grossniklaus U, Ringli C (2017) LRX Proteins play a crucial role in pollen grain and pollen tube cell wall development. Plant Physiol. doi: 10.1104/pp.17.01374

Open Access

This Swiss-led study looks into the role of LRX proteins during cell wall formation and how they affect pollen germination and pollen tube formation. The authors took advantage of the molecular tools produced by Paul Knox (University of Leeds) as part of his Plant Probes project.


Vernon I, Liu J, Goldstein M, Rowe J, Topping J, Lindsey K (2017) Bayesian uncertainty analysis for complex systems biology models: emulation, global parameter searches and evaluation of gene functions. BMC Syst Biol. doi: 10.1186/s12918-017-0484-3 Open Access

Keith Lindsey (University of Durham) leads this paper that applies a Bayesian statistical methodology to analyse a model of hormonal crosstalk in the Arabidopsis root. They show that this technique can provide new insight into the behavior of models and enables the identification of new interesting rate parameters.

Arabidopsis Research Roundup: September 6th

This largest ever Arabidopsis Research Roundup (ARR) includes 6 papers from Norwich Research Park (NRP), including three featuring Cyril Zipfel (TSL) as a co-author on papers that investigate different aspects of plant immune signaling. Elsewhere on the NRP site Veronica Grieneisen (JIC) is a co-author on a study that defines the root auxin maximum whilst Dale Sanders and Saskia Hogenhout lead a paper that defines a method for the analysis of calcium signaling. Finally Robert Sablowski’s group at the JIC investigates the role of the DELLA proteins during meristem development.

Elsewhere investigators from Kew Gardens and Bangor University have used nanopore sequencing for the facile characterisation of field populations of Arabidopsis. Similarly Seth Davies (University of York) is part of a collaboration that looks how alterations in the circadian clock might affect plant fitness.

Verena Kriechbaumer (Oxford Brookes) leads a phylogenetic study into the conservation of auxin biosynthesis genes whilst Hilary Rodgers (Cardiff University) is a co-author on a Chinese-led study that looks into role of cadmium on the Arabidopsis cell cycle.

This ARR is full of examples of UK researchers involved in global collaborations. This includes Cambridge researchers involved in a proteomic analysis of microsomes, Justin Goodrich from the University of Edinburgh as part of a US-led study that defines the regulation of the PRC2 complex and Katherine Denby (University of York) as a member of a consortium that has performed a network analysis of jasmonic acid signaling.

Finally are two studies in which the research takes place within a single institution. Malcolm Hawksford (Rothamsted Research) looks at the effect of wheat transcription factors in the response to the heavy metal zinc whilst Emily Larson and Mike Blatt (University of Glasgow) investigate the role of clathrin on plant vesicular transport.


D’Ambrosio JM, Couto D, Fabro G, Scuffi D, Lamattina L, Munnik T, Andersson MX, Alvarez ME, Zipfel C, Laxalt AM (2017) PLC2 Regulates MAMP-Triggered Immunity by Modulating ROS Production in Arabidopsis. Plant Physiol 10.1104/pp.17.00173

This Argentinian-led study includes Cyril Zipfel (TSL) as a co-author on this work that uses miRNA-mediated gene silencing to assess the role of the phosphoinositide-specific phospholipase C (PI-PLC) in plant immune signaling.


Imkampe J, Halter T, Huang S, Schulze S, Mazzotta S, Schmidt N, Manstretta R, Postel S, Wierzba M, Yang Y, vanDongen WM, Stahl M, Zipfel C, Goshe MB, Clouse S, de Vries SC, Tax F, Wang X, Kemmerling B (2017) The Arabidopsis Leucine-rich Repeat Receptor Kinase BIR3 Negatively Regulates BAK1 Receptor Complex Formation and Stabilizes BAK1. Plant Cell. 10.1105/tpc.17.00376

Cyril Zipfel (TSL) is a co-author on this global collaboration that further defines the role of the BAK1 receptor in hormone and immune signaling through its interaction with two LRR-RK proteins (BIR2 and BIR3).


Singh V, Perraki A, Kim SY, Shrivastava S, Lee JH, Zhao Y, Schwessinger B, Oh MH, Marshall-Colon A, Zipfel C, Huber SC (2017) Tyrosine-610 in the Receptor Kinase BAK1 Does Not Play a Major Role in Brassinosteroid Signaling or Innate Immunity. Front Plant Sci. 10.3389/fpls.2017.01273

Cyril Zipfel (TSL) is a co-author on this US-led manuscript that again looks into the role of the BRI1-ASSOCIATED KINASE1 (BAK1) on plant immune signaling. Importantly they show that the phosphorylation of tyrosine-610 is actually not necessary for this proteins role in brassinosteroid or immune signaling


Di Mambro R, De Ruvo M,,, Pacifici E, Salvi E, Sozzani R, Benfey PN,, Busch W, Novak O, Ljung K, Di Paola L, Marée AFM, Costantino P, Grieneisen VA, Sabatini S (2017) Auxin minimum triggers the developmental switch from cell division to cell differentiation in the Arabidopsis root. Proc Natl Acad Sci U S A 10.1073/pnas.1705833114

Veronica Grieneisen (JIC) is a co-corresponding author on this work with Sabrina Sabatini from the University of Rome. They define the auxin minimum, a newly characterised determinat of root patterning that delineates the separation of root division and the differentiation zones. This is defined by the interaction between cytokinin and auxin signaling cascades.

Veronica discusses this paper on the GARNet YouTube channel: https://www.youtube.com/watch?v=gYdL6eddOcA


Vincent TR, Canham J, Toyota M, Avramova M, Mugford ST, Gilroy S, Miller AJ, Hogenhout S, Sanders D (2017) Real-time In Vivo Recording of Arabidopsis Calcium Signals During Insect Feeding Using a Fluorescent Biosensor. J Vis Exp. 10.3791/56142

Dale Sanders and GARNet committee member Saskia Hogenhout (JIC) lead this study that describes an imaging technique that allows for the real time assessment of calcium dynamics using a fluorescently tagged sensor.


Serrano-Mislata A, Bencivenga S, Bush M, Schiessl K, Boden S, Sablowski R (2017) DELLA genes restrict inflorescence meristem function independently of plant height. Nature Plants. 10.1038/s41477-017-0003-y

Robert Sablowski (JIC) leads this paper that investigates the role of DELLA proteins in the control of cell cycle regulators and how this impacts meristem size in both barley and Arabidopsis. Read more about it on the John Innes Centre website.


Parker J, Helmstetter AJ, Devey D, Wilkinson T, Papadopulos AST (2017) Field-based species identification of closely-related plants using real-time nanopore sequencing. Sci Rep. 10.1038/s41598-017-08461-5 Open Access

This investigation led by researchers at Kew Gardens and at the Bangor University use Real Time Nanopore Sequencing (RTnS) that allows for rapid species identification in the field and that combining RTnS and laboratory-based high-throughput sequencing leads to a significant improvement in genome assembly.


Rubin MJ, Brock MT, Davis AM, German ZM, Knapp M, Welch SM, Harmer SL, Maloof JN7, Davis SJ, Weinig C (2017) Circadian rhythms vary over the growing season and correlate with fitness components. Mol Ecol. 10.1111/mec.14287 Open Access

Seth Davies (University of York) is a co-author on this US-led work that conducts a study of field-growth Arabidopsis to evaluate the contribution of the circadian clock toward survival and fecundity. They show that variation in clock function correlates with growth performance in a natural environment.


Poulet A, Kriechbaumer V (2017) Bioinformatics Analysis of Phylogeny and Transcription of TAA/YUC Auxin Biosynthetic Genes. Int J Mol Sci. 10.3390/ijms18081791 Open Access

The paper from Oxford Brookes University provides a phylogenetic analysis of TAA/TAR (tryptophan aminotransferase related) and YUCCA proteins that are involved in auxin biosynthesis. In addition they provide tissue and cell-specific information about the function of these proteins and that their function is conserved in lower plant species.


Cui W, Wang H, Song J, Cao X, Rogers HJ, Francis D, Jia C, Sun L, Hou M, Yang Y, Tai P, Liu W (2017) Cell cycle arrest mediated by Cd-induced DNA damage in Arabidopsis root tips. Ecotoxicol Environ Saf. 10.1016/j.ecoenv.2017.07.074 Open Access

Hilary Rodgers (Cardiff University) is a co-author on this Chinese-led study that looks into the effect of cadmium treatment on the regulation of the cell cycle and DNA damage repair. They show that different cadmium concentrations effect different phases of the cell cycle.


Alqurashi M, Thomas L, Gehring C, Marondedze C (2017) A Microsomal Proteomics View of H₂O₂- and ABA-Dependent Responses. Proteomes. 10.3390/proteomes5030022 Open Access

This international collaboration includes members of the Cambridge Centre for Proteomics and conducts a quantitative analysis of the Arabidopsis microsomal proteome following treatment with hydrogen peroxide or ABA. Perhaps unsurprisingly a high number of proteins characterized as ‘responsing to stress’ were found upregulated following treatment with H2O2 or ABA.


Xiao J, Jin R, Yu X, Shen M, Wagner JD, Pai A, Song C, Zhuang M, Klasfeld S, He C, Santos AM, Helliwell C, Pruneda-Paz JL, Kay SA, Lin X, Cui S, Garcia MF, Clarenz O, Goodrich J, Zhang X, Austin RS,, Bonasio R, Wagner D (2017) Cis and trans determinants of epigenetic silencing by Polycomb repressive complex 2 in Arabidopsis. Nature Genet 10.1038/ng.3937

Justin Goodrich (University of Edinburgh) is a co-author on this US-led study that looks into the role of Polycomb response element (PREs) in directing the placement of the Polycomb repressive complex 2 (PRC2) via their interaction with a newly identified transcription factors. Justin has recently discussed a paper on a similar topic on the GARNet YouTube channel.


Hickman R, van Verk MC, Van Dijken AJH, Pereira Mendes M, Vroegop-Vos IA, Caarls L, Steenbergen M, Van Der Nagel I, Wesselink GJ, Jironkin A, Talbot A, Rhodes J, de Vries M, Schuurink RC, Denby K, Pieterse CMJ, Van Wees SCM (2017) Architecture and Dynamics of the Jasmonic Acid Gene Regulatory Network. The Plant Cell 10.1105/tpc.16.00958 Open Access

GARNet committee member Katherine Denby (University of York) is a member of this large consortium of researchers who have performed a network analysis on the dynamics of jasmonic acid signaling


Evens NP, Buchner P, Williams LE, Hawkesford MJ (2017) The role of ZIP transporters and group F bZIP transcription factors in the Zn-deficiency response of wheat (Triticum aestivum) Plant J. 10.1111/tpj.13655 Open Access

Malcolm Hawkesford (Rothamsted Research) leads this study that investigate a set of wheat bZIP transcription factors and ZIP transporters that are involved in the uptake and transport of zinc. As part of this work they use Arabidopsis to test the conserved function of these wheat proteins.


Larson ER, Van Zelm E, Roux C, Marion-Poll A, Blatt MR (2017) Clathrin Heavy Chain subunits coordinate endo- and exocytic traffic and affect stomatal movement. Plant Physiol. 10.1104/pp.17.00970 Open Access

Mike Blatt and Emily Larson (University of Glasgow) are the co-corresponding authors on this study that looks into the role of clathrin heavy chain on vesicular transport in Arabidopsis. They looked at clathrin mutants to show that the protein plays an unsurprisingly important role in both endo- and exocytosis.

Arabidopsis Research Roundup: December 29th

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Published on: December 28, 2016

The final Research Roundup of 2016 includes two papers that take different strategies toward the ultimate aim of crop improvement and use Arabidopsis as a tool for their initial discoveries. Firstly Christine Raines (University of Essex) uses a transgenic approach to upregulate enzymes of the calvin cycle while researchers from Rothamstead and Oxford use a chemical intervention strategy. Both of these strategies are successful in increasing yield.

Second are a set of back-to-back papers featuring Xiaoqi Feng (JIC) that investigate DNA methylation patterns in both male and female gametes.

Finally Henrik Jonsson (SLCU) leads a paper that precisely defines the parameters that are important in determining the relationship between cell size, location and cytokinesis.

 

Simkin AJ, Lopez-Calcagno PE, Davey PA, Headland LR, Lawson T, Timm S, Bauwe H, Raines CA (2016) Simultaneous stimulation of the SBPase, FBP aldolase and the photorespiratory GDC-H protein increases CO2 assimilation, vegetative biomass and seed yield in Arabidopsis. Plant Biotechnol J http://dx.doi.org/10.1111/pbi.12676

Open Access
Raines
GARNet Committee Member Christine Raines leads this UK-German study that alters the amounts of three calvin cycle enzymes and assesses the subsequent change in photosynthetic rate in Arabidopsis plants. These enzymes sedoheptulose 1,7-bisphosphatase (SBPase), fructose 1,6-bisphophate aldolase (FBPA) and the glycine decarboxylase H-protein (GDC-H) were overexpressed either individually or together and each plant shows an increase in the quantum efficiency of photosystem II. This results in improved CO2 fixation and a concomitant increase in leaf area and biomass. Overall the authors have shown that this transgenic gene stacking approach can have potential for improving plant productivity.


Griffiths CA, Sagar R, Geng Y, Primavesi LF, Patel MK, Passarelli MK, Gilmore IS, Steven RT, Bunch J,, Paul MJ, Davis BG (2016) Chemical intervention in plant sugar signalling increases yield and resilience. Nature

http://dx.doi.org/10.1038/nature20591

This study is a collaboration between Rothamstead Research and the University of Oxford and has been featured in a recent Nature podcast. This paper outlines a chemical intervention strategy to improve crop productivity and includes some fundamental work performed in Arabidopsis. They used a ”signaling-precursor concept” to design and synthesise a plant permeable version of Trehalose-6-phosphate (T6P), which could readily be uptaken and activated by sunlight in planta. Addition of T6P to wheat increases grain yield whilst when applied to leaf tissue it improves recovery from drought stress. This is an exciting test case to show the potential of chemical intervention yet the authors are rightly cautious when considering the general use of the compound given the variability of field conditions.
Nature


Hsieh PH, He S,, Buttress T, Gao H, Couchman M, Fischer RL, Zilberman D, Feng X (2016) Arabidopsis male sexual lineage exhibits more robust maintenance of CG methylation than somatic tissues. PNAS http://dx.doi.org/10.1073/pnas.1619074114

Xiaoqi Feng (John Innes Centre) is the corresponding author on this study that investigates the transgenerational maintenance of methylation through the male germline. They undertook the challenging purification of Arabidopsis pollen sperm and vegetative cells from both wildtype plants and plants that contains mutations within different DNA methytransferases. They show that background methylation is equivalent in sperm, vegetative and somatic cells but that specific CG methylation is higher in pollen sperm and vegetative cells than in somatic cells. The authors suggest that this allows more accurate inheritance of methylation patterns across successive generations.


Park K, Kim MY, Vickers M, Park JS, Hyun Y, Okamoto T, Zilberman D, Fischer RL, Feng X, Choi Y, Scholten S (2016) DNA demethylation is initiated in the central cells of Arabidopsis and rice. PNAS http://dx.doi.org/10.1073/pnas.1619047114

In this second of back-to-back papers, Xiaoqi Feng is a co-author on an international study that looks into the role of the DEMETER DNA demethylase on the control of gene expression in the endosperm. This tissue results from the fusion of a male pollen sperm cell and the female central cell and is associated with significant demethylation. This study documents the first genome-wide analysis of DNA methylation in the female central cell in Arabidopsis. They show that DNA demethylation requires DEMETER function but that it is likely not associated with the downregulation of the MET1 methytransferase. Therefore the authors suggest that characteristic endospermal DNA demethylation occurs through locus-specific activity.


Willis L,, Refahi Y, Wightman R, Landrein B, Teles J, Huang KC,, Meyerowitz EM,,, Jönsson H (2016) Cell size and growth regulation in the Arabidopsis thaliana apical stem cell niche. PNAS http://dx.doi.org/10.1073/pnas.1616768113

Henrik Jonsson (Sainsbury Lab Cambridge) is the corresponding author on this UK-US collaboration that uses a 4D imaging pipeline to track the growth of epidermal cells in the Arabidopsis shoot apical meristem (SAM). They suggest that neither cell size or cell age are determinants for progression to cytokinesis, which is also independent of cell contact topologies and the cell position within the SAM. However they find that a more complex mix of parameters determine the constraints on determination of cell size. Following cell division they also show that a smaller daughter cell will grow at a faster rather than its larger sister, a finding that the authors suggest challenges present models of growth regulation.Jonsson

Arabidopsis Research Roundup: August 8th

This weeks Arabidopsis Roundup contains a wide breadth of UK research. Firstly the lab of Jurriaan Ton undertakes a global analysis into the role of methylation in the immune response. Jurriaan kindly provides a short audio description of this work. Secondly Dame Caroline Dean’s lab further add to our understanding of the vernalisation response in Arabidopsis. Thirdly is work from Rothamstead that evaluates the fatty acid composition of the seed aleurone while fourthly is a study from Durham and Oxford Brookes that introduces a novel regulator of autophagy. Finally is a study that adds clarity to the phenotypic effects resulting from ascorbic acid deficiency.

López Sánchez A, H M Stassen J, Furci L, Smith LM, Ton J (2016) The role of DNA (de)methylation in immune responsiveness of Arabidopsis Plant Journal http://dx.doi.org/10.1111/tpj.13252 Open Access

Jurriaan Ton is the corresponding for study from the University of Sheffield that looks into the role of reversible methylation on the Arabidopsis immune response. Methylation is a well known regulator of gene expression and in this research the authors attempt to interrogate its effect on the immune response. Hypo-methylated mutants are more resistant, whilst hyper-methylated mutants are more suspectible to the biotrophic pathogen Hyaloperonospora arabidopsidis (Hpa). Downstream gene expression changes in these methylation mutants focus at the level of cell-wall modification and salicylic acid (SA)-responses. Oppositely the hypo-methylated mutant nrpe1 is more suspective to the necrotrophic pathogen Plectosphaerella cucumerina whilst the hyper-methylated ros1 mutant is resistant to this organism. The Ton-lab has been involved in the discovery of the exciting phenomon of transgenerational acquired resistance, and both nrpe1 and ros1 fail to develop this response against Hpa. Global gene expression shows that either NRPE1 or ROS1 influence about 50% of the gene expression changes that occur following Hpa infection. Finally since less than 15% of genes with altered gene expression reside close to NRPE1 or ROS1, the authors are able to propose that much of this regulation is due to methylation effects that act in trans- throughout the genome.

Jurriaan kindly provides a comprehensive description of this work:


Qüesta JI, Song J, Geraldo N, An H, Dean C (2016) Arabidopsis transcriptional repressor VAL1 triggers Polycomb silencing at FLC during vernalization Science. 353(6298):485-8 http://dx.doi.org/10.1126/science.aaf7354

VAL_pic
From http://science.sciencemag.org/content/353/6298/485

Dame Caroline Dean (John Innes Centre) is the lead author of this manuscript that builds upon the portfolio of work from her lab aimed at characterising the vernalization response. This work again uses the FLOWERING LOCUS C (FLC) gene as a model to study the factors that allow gene-silencing mediated by Polycomb silencing complexes. The authors find that a single intragenic point mutation prevents nucleation of the homeodomain-Polycomb repressive complex 2 (PHD-PRC2) to this region, a process that involves the transcriptional repressor VAL1. In the wildtype FLC locus the localisation of VAL1 promotes transcriptional silencing through histone deacylation through interaction with the conserved apoptosis- and splicing-associated protein (ASAP) complex. This study adds an additional layer of molecular complexity to the process of regulating the FLC locus and provides insight into the important role for primary sequence-specific targeting during gene silencing.

Bryant F, Munoz-Azcarate O, Kelly AA, Beaudoin F, Kurup S, Eastmond PJ (2016) Acyl carrier protein DESATURASE 2 and 3 are responsible for making omega-7 fatty acids in the aleurone Plant Physiology http://dx.doi.org/10.1104/pp.16.00836 Open Access

Peter Eastmond (Rothamstead) leads this work that investigates the components that determine seed fatty acid content. Specifically Omega-7 monounsaturated fatty acids (ω-7s) are enriched in the aleurone of Arabidopsis seeds so this study used a Multiparent Advanced Generation Inter-Cross population to identify a QTL linked to ω-7 content that includes the ACYL-ACYL CARRIER PROTEIN DESATURASE1 (AAD1) and AAD3 genes. AAD family members possess both stearoyl- and palmitoyl-ACP Δ9 desaturase activity and aad3 mutants show a significant reduction in ω-7 content, which is common with mutants in other AAD family members. In addition the authors show that the FATTY ACID ELONGASE1 protein is required for accumulation of long-chain ω-7s in the aleurone. Overall this research provides new insight into the pathway that produces ω-7s in the aleurone, indicating that these genes might represent a target for future strategies to alter seed fatty acid content.

Wang P, Richardson C, Hawes C, Hussey PJ.(2016) Arabidopsis NAP1 Regulates the Formation of Autophagosomes Current Biology http://dx.doi.org/10.1016/j.cub.2016.06.008

NAP1_pic
From http://www.sciencedirect.com/science/article/pii/S0960982216306200

This is collaborative effort between the labs of Patrick Hussey (Durham) and Chris Hawes (Oxford Brookes) investigates the role of the NAP1 protein, which is a member of the SCAR/WAVE complex, on the formation of autophagosomes. These organelles are induced by certain stress conditions and fewer are produced in nap1 mutants after starvation stress. This also corresponds to wildtype NAP1 localisation. Concomitantly nap1 mutants, as well as mutants of other members of SCAR/WAVE complex, are more suspectible to nitrogen starvation and is less tolerant to salt stress. The best characterised role of the SCAR/WAVE complex is during ARP2/3-mediated actin nucleation yet this study demonstrates an addition function as a regulatory of autophagy.

Lim B, Smirnoff N, Cobbett CS, Golz JF (2016) Ascorbate-Deficient vtc2 Mutants in Arabidopsis Do Not Exhibit Decreased Growth Front Plant Sci. 7:1025

http://dx.doi.org/10.3389/fpls.2016.01025 Open Access

Nick Smirnoff (Exeter) is a co-author on the Australian-led research into Arabidopsis vtc mutants, which have a significant reduction in ascorbate-acid levels. Ascorbate is synthesized via the L-galactose pathway, the first enzyme of which is encoded by the paralogs VITAMIN C2 (VTC2) and VTC5. This study characterises the growth of a vtc2 T-DNA mutant that has a 30% reduction in ascorbate levels. Surprisingly this does not result in any signficant phenotypic and they suggest that a previously characterised growth reduction in other vtc2 mutant alleles is likely due to unknown genetic lesions.

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