GARNet Research Roundup: December 21st 2018

This bumper Festive Edition of the GARNet Research Roundup begins with two papers that have Beatriz Orosa-Puente as lead author following her work on SUMOylation with Ari Sadanandom at Durham. These papers looks at the role of SUMOylation in either auxin-mediated hydropatterning or in the defence response. Malcolm Bennett at Nottingham is a co-author on both papers and provided an audio description of the auxin-focused paper on the GARNet YouTube channel.

The next three papers are from the University of Edinburgh, the first that defines the role of HECT ubiquitin ligases in the defence response, the second that conducts a proteomic analysis of the GIGANTEA-interactome and the third that introduces a set of new tools for inducible gene expression in Arabidopsis roots.

The sixth and seventh papers feature authors from the John Innes Centre. Martin Howard and Caroline Dean are corresponding authors on a multi-scale analysis of the factors that control FLC expression whilst Myriam Charpentier’s lab has contributed to an investigation about LINC complexes in Medicago.

David Salt and Levi Yant from Nottingham lead the next paper that provides an analysis of the genetic determinants of adaptation to different salt conditions.

The final three papers are from Cambridge. Firstly Ian Henderson is the corresponding author on work that looks at crossover rates in specific disease resistance loci. Second is work from the Paszkowski lab at SLCU that introduces a new method for the analysis of active retrotransposons in crop plants whilst finally James Locke, also at SLCU, uses the method of distributed delays to simplify the complexity of biological network models.


Orosa-Puente B, Leftley N, von Wangenheim D, Banda J, Srivastava AK, Hill K, Truskina J, Bhosale R, Morris E, Srivastava M, Kümpers B, Goh T, Fukaki H, Vermeer J, Vernoux T, Dinneny JR, French AP, Bishopp A, Sadanandom A , Bennett MJ (2018) Roots branch towarss water by post-translational modification of the transcription factor ARF7 Science DOI: 10.1126/science.aau3956

Orosa B, Yates G, Verma V, Srivastava AK, Srivastava M, Campanaro A, De Vega D, Fernandes A, Zhang C, Lee J, Bennett MJ, Sadanandom A (2018) SUMO conjugation to the pattern recognition receptor FLS2 triggers intracellular signalling in plant innate immunity. Nat Commun. doi: 10.1038/s41467-018-07696-8 Open Access

http://science.sciencemag.org/content/362/6421/1407

Beatriz Orosa-Puente is the lead author on two publications that have arisen from a collaboration between the labs of Ari Sadanandom at Durham and Malcolm Bennett at Nottingham. In the first paper Beatriz is co-first author with Nicola Leftley and Daniel von Wangenheim in research that links the auxin response, SUMOylation and the search for water. They reveal a novel mechanism for controlling the auxin response in which SUMOylation regulates the interaction between the ARF7 and IAA3 proteins. In turn this controls asymmetric expression of genes downstream of ARF7 and determines how different parts of the root response to the presence or absence of water.

The second paper continues with the Sadanandom lab’s focus on SUMOylation, in this case during control of the defence response. They show that SUMO is conjugated to the FLAGELLIN-SENSITIVE 2 (FLS2) receptor that senses bacterial flagellin. This releases downstream cytoplasmic effectors and enhances the immune response. The authors show that there is additional complexity to this system by also showing that flagellin induces degradation of the deSUMOylating enzyme Desi3a, thus allowing the plant to make a stronger immune response.


Furniss JJ, Grey H, Wang Z, Nomoto M, Jackson L, Tada Y, Spoel SH (2018) Proteasome-associated HECT-type ubiquitin ligase activity is required for plant immunity. PLoS Pathog. doi: 10.1371/journal.ppat.1007447 Open Access

James Furniss is the lead author on this paper from the lab of current GARNet Chairman Steven Spoel at the University of Edinburgh. They show that a family of HECT domain-containing ubiquitin protein ligases (UPLs) are involved in defence responses mediated by the hormone salicylic acid (SA). Upl3 mutants show reprogramming of the entire SA transcriptional response and they are unable to establish immunity against a hemi-biotrophic pathogen, demonstrating their key role in this important process.


https://febs.onlinelibrary.wiley.com/doi/abs/10.1002/1873-3468.13311

Krahmer J, Goralogia GS, Kubota A, Zardilis A, Johnson RS, Song YH, MacCoss MJ, LeBihan T, Halliday KJ, Imaizumi T, Millar AJ (2018) Time-resolved Interaction Proteomics of the GIGANTEA Protein Under Diurnal Cycles in Arabidopsis. FEBS Lett. doi: 10.1002/1873-3468.13311 Open Access

This paper is a collaboration between researchers in Edinburgh and Seattle for which Johanna Krahmer is lead author. They used a proteomic approach to identify proteins that interacted with a tagged-version of the key circadian regulator GIGANTEA. They successfully identified the novel transcription factor CYCLING DOF FACTOR (CDF)6. CDF6 was confirmed as interacting with GI and playing a role in the control of flowering. The time series of proteomic data produced in this study is available for use by any other interested researcher.

http://proteomecentral.proteomexchange.org/cgi/GetDataset?ID=PXD006859


Machin FQ, Beckers M, Tian X, Fairnie A, Cheng T, Scheible WR, Doerner P (2018) Inducible reporter/driver lines for the Arabidopsis root with intrinsic reporting of activity state. Plant Journal. doi: 10.1111/tpj.14192

Frank Qasim Machin is the lead author on this Technical Advance from Peter Doerner’s lab at the University of Edinburgh. They have developed a Gateway-based system for tightly controlled inducible expression across all the major cell types of the Arabidopsis roots. They have fully characterised reference driver lines that can be adapted for specific experimental requirements and hope that this contributes towards enhancing reproducibility of qualitative and quantitative analyses.


https://www.sciencedirect.com/science/article/pii/S2405471218304368?via%3Dihub

Antoniou-Kourounioti RL, Hepworth J, Heckmann A, Duncan S, Qüesta J, Rosa S, Säll T, Holm S, Dean C, Howard M (2018) Temperature Sensing Is Distributed throughout the Regulatory Network that Controls FLC Epigenetic Silencing in Vernalization. Cell Syst. doi: 10.1016/j.cels.2018.10.011 Open Access

This work results from the successful collaboration between Caroline Dean and Martin Howard at the John Innes Centre and includes Rea Antoniou-Kourounioti and Jo Hepworth as co-first authors. They attempt to understand how the upregulation of VERNALIZATION INSENSITIVE3 (VIN3) and silencing of FLOWERING LOCUS C (FLC) is controlled during fluctuating temperatures over month-long time scales. They develop a mathematical model that integrates information from hour, day and month-long datasets to show that temperature is sensed across the entire regulatory network and not focussed on specific nodes. This allows a final effect to only be realised once all parts of the network have been appropriately changed. This model with matches new field data and therefore represents a predictive tool for the effects of climate change on plant growth.


Newman-Griffis AH, Del Cerro P, Charpentier M, Meier I (2018) Medicago LINC complexes function in nuclear morphology, nuclear movement, and root nodule symbiosis Plant Physiol. http://www.plantphysiol.org/content/early/2018/12/10/pp.18.01111 Open Access
Pablo del Cerro and Myriam Charpentier at the John Innes Centre are co-authors on this paper from Iris Meier’s lab at The Ohio State University. They identify and characterise the Linker of Nucleoskeleton and Cytoskeleton (LINC) family of nucleus-membrane-associated proteins. They show that, as in Arabidopsis, these proteins are required for nucleus movement in the root tip cells of Medicago truncatula and that they are an important contributor to nodulation. Both Iris and Myriam are members of the INDEPTH consortium that includes researchers who study this broad area of plant cell biology.


https://www.pnas.org/content/early/2018/12/11/1816964115.long

Busoms S, Paajanen P, Marburger S, Bray S, Huang XY, Poschenrieder C, Yant L, Salt DE (2018) Fluctuating selection on migrant adaptive sodium transporter alleles in  coastal Arabidopsis thaliana. Proc Natl Acad Sci U S A. doi: 10.1073/pnas.1816964115 Open Access

This UK-Sino-Spanish collaboration is led by David Salt and Levi Yant at the University of Nottingham. Silvia Busoms is the first author on the study that investigates the genetics of adaptive salt tolerance in a cohort of 77 individuals grown across a salinity gradient in a coastal region of Catalonia. By integrating their data with the 1135 genomes project they are able to trace the ancestry of these populations and define that growth in high salt conditions is associated with increased expression of the high-affinity K+ transporter (HKT1;1). This demonstrates that this gene plays a key role in the adaptation to salt stress.


Serra H, Choi K, Zhao X, Blackwell AR, Kim J, Henderson IR. Interhomolog polymorphism shapes meiotic crossover within the Arabidopsis RAC1 and RPP13 disease resistance genes (2018) PLoS Genet. doi: 10.1371/journal.pgen.1007843 Open Access

This UK-Korean collaboration is led by the Heidi Serra and Ian Henderson at the University of Cambridge. They mapped the meiotic crossover hotspots that are located within the RAC1 and RPP13 disease resistance genes in Arabidopsis. They assessed these locations in plants with altered recombination rates and surprisingly showed that these effects have little impact at the RAC1 loci. Therefore they show that chromosome location and local chromatin environment are important for regulation of crossover activity. Overall they demonstrate that interhomolog divergence is important in shaping recombination within plant disease resistance genes and crossover hotspots.


Cho J, Benoit M, Catoni M, Drost HG, Brestovitsky A, Oosterbeek M, Paszkowski J (2018) Sensitive detection of pre-integration intermediates of long terminal repeat retrotransposons in crop plants. Nat Plants. doi: 10.1038/s41477-018-0320-9

Open Access with link: rdcu.be/bdLjy

For the second edition in succession, the GARNet research roundup features work from Jerzy Paszkowski’s lab at SLCU. In this case Jungnam Cho is lead author on work that has developed a new technique called ALE-seq (amplification of LTR of eclDNAs followed by sequencing) for analysis of transposon-rich genomes from crop plants. Through characterisation of extrachromosomal linear DNA (eclDNA), ALE-seq allows the identification of active transposons. The authors use this technique in both rice and tomato and successfully identify a set of developmentally regulated transposable elements. This paper includes details of a bioinformatic pipeline that is adapted for ALE-seq data analyses, the scripts for which are available on GitHub.


Tokuda IT, Akman OE, Locke JCW. Reducing the Complexity of Mathematical Models for the Plant Circadian Clock by Distributed Delays (2018) J Theor Biol. doi: 10.1016/j.jtbi.2018.12.014

This UK-Japanese study includes James Locke at SLCU as corresponding author. They address the challenge of integrating an increasing number of parameters into large biological network models. Their system of study is the Arabidopsis circadian clock and they use the method of distributed delays to simplify the complexity of existing models. They demonstrate this effect by updating a model that explains the regulation of the PRR9 and PRR7 genes by LHY. They use recent experimental data and revise the previous model to show that it is more accurately reproduces the LHY-induction experiments of core clock genes. As stated they show that overall use of distributed delays facilitates the optimisation and reformulation of genetic network models.

GARNet Research Roundup: November 22nd 2018

This GARNet Research Roundup begins with two studies from the University of Sheffield. First is research from Jurriaan Ton’s lab that looks at the interaction between CO2 concentration, the soil microbiome and plant growth. The second paper from Matt Davey and Peter Quick looks at the effect of cold acclimation on freezing tolerance in Arabidpsis lyrata.

The third study includes authors from Dundee and Durham and also looks at an impact of altered CO2 concentrations, in this case on nitrogen assimilation.

The next paper looks at the role of a GA signaling module on endosperm expansion during seed germination and includes authors from Nottingham and Birmingham.

The fifth paper includes Richard Morris at the JIC as a co-author and looks at the relationship between calcium signaling and changes in cellular pH. The penultimate study features co-authors from Warwick and Exeter in work that looks at the role of 3′-O-β-D-ribofuranosyladenosine during plant immunity. Finally is a paper that includes Steve Long from Lancaster and characterises the rubisco-chaperone BSD2.


Williams A, Pétriacq P, Beerling DJ, Cotton TEA, Ton J (2018) Impacts of Atmospheric CO(2) and Soil Nutritional Value on Plant Responses to Rhizosphere Colonization by Soil Bacteria. Front Plant Sci. doi: 10.3389/fpls.2018.01493

https://www.frontiersin.org/articles/10.3389/fpls.2018.01493/full

Open Access

Alex Williams is the lead author of this paper and works with Jurriaan Ton at the University of Sheffield. The impact of the soil rhizosphere on plant growth is emerging as an important growth determinant. In this paper the authors assess the role of altered [CO2] and soil carbon (C) and nitrogen (N) concentration in the colonisation of Arabidopsis roots by two different bacteria. Firstly they showed that altered [CO2] did not change the growth dynamics of the saprophytic bacteria Pseudomonas putida KT2440 and was independent of soil C or N. In contrast growth of the rhizobacterial strain Pseudomonas simiae WCS417 was sensitive to both changing [CO2] and soil composition. These results show the importance of the interaction between atmospheric CO2 and soil nutritional status during plant interactions with soil bacteria.


Davey MP, Palmer BG, Armitage E, Vergeer P, Kunin WE, Woodward FI, Quick WP (2018) Natural variation in tolerance to sub-zero temperatures among populations of Arabidopsis lyrata ssp. petraea. BMC Plant Biol. doi: 10.1186/s12870-018-1513-0

Open Access

Matthew Davey, now working in Cambridge, collaborated with Peter Quick at the University of Sheffield on this research that looks at the tolerance of Arabidopsis lyrata to freezing. They showed that populations from locations with colder winter climates were better able to survive subzero temperatures, particular when they have been acclimated at near zero for longer periods. This demonstrates that the adaptation of plants to cold temperatures allows them to better survive freezing, although surprisingly this effect is lessened when this acclimation period does not occur.


Andrews M, Condron LM, Kemp PD, Topping JF, Lindsey K, Hodge S, Raven JA (2018) Effects of elevated atmospheric [CO2] on nitrogen (N) assimilation and growth of C3 vascular plants will be similar regardless of N-form assimilated. J Exp Bot. doi: 10.1093/jxb/ery371

This UK-New Zealand collaboration is led by Mitchell Andrews and looks at the effect of elevated [CO2] on the nitrogen (N) assimilation when the plant is exposed to a variety of different N-sources. They show that in C3 plants the overall N assimilated will be the same whether the plant is under ammonium (NH4+) nutrition or under nitrate (NO3-) nutrition. These results are contrary to previous results that suggest elevated [CO2] reduces plant growth under NO3- nutrition.


Sánchez-Montesino R, Bouza-Morcillo L, Marquez J, Ghita M, Duran-Nebreda S, Gómez L, Holdsworth MJ, Bassel G, Oñate-Sánchez L (2018) A regulatory module controlling GA-mediated endosperm cell expansion is critical for seed germination in Arabidopsis. Mol Plant. doi: 10.1016/j.molp.2018.10.009 

https://www.sciencedirect.com/science/article/pii/S1674205218303356

Open Access

This Spanish-led project includes authors from the Universites of Nottingham and Birmingham. They look at the influence of a GA signalling module on endosperm cell separation, which is essential for Arabidopsis seed germination. They show the NAC transcription factors NAC25 and NAC1L control expression of the EXPANSION2 gene and that the GA signalling component RGL2 has a controlling influence by repressing this activity.


Behera S, Xu Z, Luoni L, Bonza C, Doccula FG, DeMichelis MI, Morris RJ, Schwarzländer M, Costa A (2018) Cellular Ca2+ signals generate defined pH signatures in plants. Plant Cell. doi: 10.1105/tpc.18.00655

Open Access

Richard Morris (John Innes Centre) is a co-author on this Italian-led study that investigates the role of Calcium ions in cell signalling. They use a set of genetically-encoded fluorescent sensors to visualise a link between Ca2+ signaling and changes in pH. If this link is maintained across all cell types it might represent an extra layer of complexity and control of cellular signal transduction.


Drenichev MS, Bennett M, Novikov RA, Mansfield J, Smirnoff N, Grant M, Mikhailov S (2018) A role for 3′-O-β-D-ribofuranosyladenosine in altering plant immunity. Phytochemistry. doi: 10.1016/j.phytochem.2018.10.016

https://www.sciencedirect.com/science/article/pii/S0031942218301997?via%3Dihub

This Russian-led study includes UK-based researchers Mark Bennett, Murray Grant, Nick Smirnoff and John Mansfield as co-authors. They show that the natural disaccharide nucleoside, 3′-O-β-D-ribofuranosyladenosine accumulated in plants infected with the bacterial pathogen P. syringae. Perhaps surprisingly the application of this nucleoside to the plant doesn’t effect bacterial multiplication, indicating that adds a significant metabolic burden to plants already battling new infections.


Conlan B, Birch R, Kelso C, Holland S, De Souza AP, Long SP, Beck JL, Whitney SM (2018) BSD2 is a Rubisco specific assembly chaperone, forms intermediary hetero-oligomeric complexes and is non-limiting to growth in tobacco. Plant Cell Environ. doi: 10.1111/pce.13473

Steve Long is a Professor at Lancaster Environment Centre and is a co-author on this Australia-led study that characterizes the role of the Rubisco chaperone BSD2 during Rubisco biogenesis. These results suggest this is the sole role of BSD2 and its activity is non-limiting to tobacco growth.

GARNet Research Roundup: July 16th

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

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

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

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

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

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


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

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

Open Access

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


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

Open Access

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


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

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


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

Open Access

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

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


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

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

Open Access

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


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

Open Access

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


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

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

Open Access

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


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

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

Open Access

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


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

doi: 10.1074/jbc.RA118.003496

Open Access

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


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

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


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

doi: 10.1371/journal.pgen.1007510 Open Access

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

GARNet Research Roundup: June 4th

This weeks GARNet Research Roundup begins with a paper from researchers at the University of Dundee, James Hutton Institute, Durham University and the University of Glasgow that characterises a functional role for alternative splicing during the cold response. Second is a paper from Newcastle University that investigates the role of the OXI1 kinase during aphid predation. Third is a paper that includes University of Bristol co-authors that looks at strigolactone signaling in moss whilst the fourth paper from researchers at Leeds and QMUL studies the role of ascorbate during photosynthesis. The final paper from Warwick and York uses gene expression data from pathogen-infected plants to generate a model for predicting a strategy for synthetic engineering of the defence response.


Calixto CPG, Guo W, James AB, Tzioutziou NA, Entizne JC, Panter PE, Knight H, Nimmo H, Zhang R, Brown JWS (2018) Rapid and dynamic alternative splicing impacts the Arabidopsis cold response transcriptome. Plant Cell doi: 10.1105/tpc.18.00177.

www.plantcell.org/content/early/2018/05/15/tpc.18.00177.long

Open Access

Cristiane Calixto and Wenbin Guo work with John Brown at University of Dundee and the James Hutton Institute and in this large-scale biology paper they characterise the role of alternative splicing (AS) during a stress response. RNAseq was performed on plants exposed to cold stress and they showed that hundreds of genes undergo AS just a few hours after temperature decrease and that this response is sensitive to small changes. The authors propose that AS is a mechanism to fine-tune changes in thermo-plasticity of gene expression and in addition they investigate the activity of the novel splicing factor U2B”-LIKE.

Christiane will discuss this research at the upcoming GARNet2018 meeting held at the University of York in September 2018.


Shoala T, Edwards MG, Knight MR, Gatehouse AMR. OXI1 kinase plays a key role in resistance of Arabidopsis towards aphids (Myzus persicae) (2018) Transgenic Res. doi: 10.1007/s11248-018-0078-x.

Open Access

This work is led by Tahsin Shoala in the lab of Angharad Gatehouse at Newcastle University and demonstrates a novel role for MAPK cascades in resistance to aphid predation. They investigate mutants in OXI1 kinase, a gene that activates MAPK signaling and demonstrate a reduction in the aphid population build-up. Furthermore they show that the effect of OXI works through a mechanism that involves callose deposition, demonstrated as oxi1 mutants lack the upregulation of a set of β-1,3-glucanase genes following predation.


Lopez-Obando M, de Villiers R, Hoffmann B, Ma L, de Saint Germain A, Kossmann J, Coudert Y, Harrison CJ, Rameau C, Hills P, Bonhomme S (2018) Physcomitrella patens MAX2 characterization suggests an ancient role for this F-box protein in photomorphogenesis rather than strigolactone signalling. New Phytol. doi: 10.1111/nph.15214

GARNet committee member Jill Harrison is a co-author on this paper that is led by Mauricio Lopez‐Obando working at Université Paris-Saclay. In Physcomitrella patens development they investigate the role of the moss ortholog of the Arabidopsis strigolactone signaling mutant MAX2. Previous work had shown that moss does response to SL signaing but they find that although Ppmax2 mutants showed defects in early development and photomorphogenesis they do not show changes in the SL response. Fascinatingly this indicates that the molecular components that control SL signaling have diverged in vascular plants and seemingly co-opted a role for MAX2 that was previously not required in mosses.


https://academic.oup.com/jxb/article/69/11/2823/4991886

Plumb W, Townsend AJ, Rasool B, Alomrani S, Razak N, Karpinska B, Ruban AV, Foyer CH. Ascorbate-mediated regulation of growth, photoprotection and photoinhibition in Arabidopsis thaliana (2018) J Exp Bot. doi: 10.1093/jxb/ery170

William Plumb (Leeds) and Alexandra Townsend (QMUL) are the lead authors on this study that investigates the importance of ascorbate during photosynthesis. In this work they analysed the growth of ascorbate synthesis mutants that are smaller and have less biomass than wildtype plants. However these plants have normal levels of non-photoinhibiton, allowing the authors to conclude that ascorbate is needed for growth but not photoprotection.


Foo M, Gherman I, Zhang P, Bates DG, Denby K (2018) A Framework for Engineering Stress Resilient Plants using Genetic Feedback Control and Regulatory Network Rewiring. ACS Synth Biol. doi: 10.1021/acssynbio.8b00037
Mathias Foo and Iulia Gherman (University of Warwick) are lead authors on work that analyses gene expression data taken from Botrytis cinerea-infected Arabidopsis. They have identified a network of genes involved in the defence response. They validate their model against previously obtained time series data and then perturb the model in two differences ways, focused on the transcription factor CHE. This analysis demonstrates the potential of combining feedback control theory with synthetic engineering in order to generate plants that are resistant to biotic stress.

https://pubs.acs.org/doi/10.1021/acssynbio.8b00037

GARNet Research Roundup: May 17th

This weeks GARNet research roundup includes six excellent papers investigating many aspects of Arabidopsis cell biology. Firstly Eirini Kaiserli from Glasgow introduces a novel regulator of blue-light signaling. Second is a paper that analyses the circadian clock with single cell resolution and is led by James Locke (SLCU) and Anthony Hall (Earlham Institute). The next two papers investigate different aspects of hormone signaling, with Keith Lindsey’s group at Durham looking at the relationshop between the HYDRA protein and the auxin response whilst Ottoline Leysers group in Cambridge looks at the link between auxin and cytokinin during shoot growth. The fifth paper from Phillip Mullineaux (University of Essex) provides a genome-wide analysis into the role of HEAT SHOCK TRANSCRIPTION FACTORA1b protein. The final paper from the lab of Piers Hemsley (James Hutton Institute, University of Dundee) should be of interest to many plant molecular biologists as they assess the functional significance of different epitope tags.


Perrella G, Davidson MLH, O’Donnell L, Nastase AM, Herzyk P, Breton G, Pruneda-Paz JL, Kay SA, Chory J, Kaiserli E (2018) ZINC-FINGER interactions mediate transcriptional regulation of hypocotyl growth in Arabidopsis. Proc Natl Acad Sci U S A.. pii: 201718099. doi: 10.1073/pnas.1718099115

Open Access

Eirini Kaiserli (University of Glasgow) leads this study that identifies the ZINC-FINGER HOMEODOMAIN 10 (ZFHD10) as a novel regulator of light signaling. ZFHD10 physically interacts with TANDEM ZINC-FINGER PLUS3 (TZP) and these proteins coassociate at promotors that are blue-light regulated. These results reveal of novel mechanism of action for the key multiple signal integrator TZP in the light regulated growth of Arabidopsis hypocotyls.

Eirini discusses this paper on the GARNet YouTube channel.


Gould PD, Domijan M, Greenwood M, Tokuda IT, Rees H, Kozma-Bognar L, Hall AJ, Locke JC (2018). Coordination of robust single cell rhythms in the Arabidopsis circadian clock via spatial waves of gene expression. Elife. 26;7. pii: e31700. doi: 10.7554/eLife.31700 Open Access

https://elifesciences.org/articles/31700

This paper is led by James Locke (SLCU) and Anthony Hall (Earlham) and investigates the circadian clock at single cell resolution. They use Arabidopsis plants grown in constant environmental conditions to show two desynchronised yet robust single cell oscillations that move both up and down the root. Their results indicate that the clock shows cell-to-cell coupling and they they modeled this relationship to recapitulate the observed waves of activity. Overall their results are suggestive of multiple coordination points for the Arabidopsis clock, which is different from the mammalian system of regulation.


http://dev.biologists.org/content/145/10/dev160572

Short E, Leighton M, Imriz G, Liu D, Cope-Selby N, Hetherington F, Smertenko A, Hussey PJ, Topping JF, Lindsey K (2018) Epidermal expression of a sterol biosynthesis gene regulates root growth by a non-cell autonomous mechanism in Arabidopsis. Development . pii: dev.160572. doi: 10.1242/dev.160572 Open Access

This collaboration between the research groups of Keith Lindsey and Patrick Hussey at the University of Durham investigates the role of the HYDRA1 (HYD1) sterol Δ8-Δ7 isomerase in epidermal patterning. This tissue shows highest HYD1 expression and hyd mutants have major root patterning defects. Tissue-specific expression of HYD1 indicates that it is involved with some type of non-cell autonomous signaling. Analysis of PIN1 and PIN2 protein expression suggests that auxin might be this functional signal


http://www.plantphysiol.org/content/early/2018/05/01/pp.17.01691.long

Waldie T, Leyser O (2018) Cytokinin targets auxin transport to promote shoot branching. Plant Physiol. 2018 May 1. pii: pp.01691.2017. doi: 10.1104/pp.17.01691.Open Access

This study from the lab of Ottoline Leyser (SLCU) investigates the integration between the plant hormones cytokinin and auxin. They investigate the role of cytokinin in shoot branching through analysis of Arabidopsis Response Regulators (ARRs) mutants. They show arr mutant phenotypes correlate with changes in stem auxin transport mediated by the PIN3, PIN4 and PIN7 efflux carriers, the expression of each respond to cytokinin signaling. Overall this study identifies a novel alternative pathway by which cytokinin impacts bud outgrowth through alterations in auxin transport.


Albihlal WS, Irabonosi O, Blein T, Persad R, Chernukhin I, Crespi M, Bechtold U, Mullineaux PM (2018) Arabidopsis Heat Shock Transcription FactorA1b regulates multiple developmental genes under benign and stress conditions. J Exp Bot. doi: 10.1093/jxb/ery142 Open Access

Phillip Mullineaux (University of Essex) leads this collaboration with French colleagues in a study that investigates the genome-wide targets of the HEAT SHOCK TRANSCRIPTION FACTORA1b (HSFA1b) protein. Under non-stress ad heat-stress conditions they showed that 1000s of genes are differentially expressed with a smaller proportion of genes showing different levels of direct interaction. The indirect targets of HSFA1b are regulated through a network of 27 transcription factors and they also provide evidence for the role of hundreds of natural antisense non-coding RNA in the regulation of HSFA1b targets. Overall they show that HSFA1b is a key regulator of environmental cues to regulate both developmental genes and those involved in stress tolerance.


Hurst CH, Turnbull D, Myles SM, Leslie K, Keinath NF, Hemsley PA (2018) Variable effects of C-terminal tags on FLS2 function – not all epitope tags are created equal. Plant Physiol. doi: 10.1104/pp.17.01700 Open Access

This study from the Hemsley lab (James Hutton Institute, University of Dundee) is a cautionary tale on the use and interpretation of results obtained from experiments with commonly-used epitope tags. They assessed the activity of plants containing transgenic FLS2 proteins, which is a receptor-like kinase (RLKs) involved in the defence response. They show that various FLS2 C-terminal epitope fusions reveal highly variable and unpredictable outputs, indicating that the presence of different tags significantly alters protein function. This finding might require a reassessment of many experiments that rely on interpreting the function of epitope-tagged proteins and has significant for many if not all plant molecular biologists.

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: March 6th.

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Published on: March 6, 2017

This weeks Arabidopsis Research Roundup includes four papers that focus on different aspects of plant cell biology. Firstly Ian Henderson’s research group in Cambridge defines the role of a critical component that determines crossover frequency in plants and other eukaryotes. Secondly Karl Oparka (Edinburgh) leads a broad collaboration that defines the mechanism of unloading of solutes and macromolecules from the root phloem. Thirdly Keith Lindsey (Durham) has developed a model that describes how auxin patterns the Arabidopsis root. Finally Mike Blatt (Glasgow) is part of a group that uses Arabidopsis as a framework for the study of ABA-signaling during stomatal movement in ferns.


Ziolkowski PA, Underwood CJ, Lambing C, Martinez-Garcia M, Lawrence EJ, Ziolkowska L, Griffin C, Choi K, Franklin FC, Martienssen RA, Henderson IR (2017) Natural variation and dosage of the HEI10 meiotic E3 ligase control Arabidopsis crossover recombination. Genes Dev

http:/​/​dx.​doi.​org/10.1101/gad.295501.116

Open Access

GARNet committee member Ian Henderson (University of Cambridge) leads this work that features collaborators from the UK, US and Poland. They use an experimental technique that allows facile analysis of recombination rates alongside a study of Arabidopsis natural variation to isolate a QTL that is critical for maintaining the correct number of crossovers during meiosis. This HEI10 gene codes for an E3 ligase (the targets of which are currently unknown) whose copy number is a key component in the control of recombination rate. Hei10 mutants have less crossovers whilst plants with extra copies of HEI10 have an increased number, especially in sub-telomeric regions of the genome. HEI10 is a highly conserved protein, demonstrating its important role to ensure appropriate levels of recombination throughout the evolution of eukaryotes.

Ian kindly takes ten minutes to discuss this paper with GARNet on our YouTube Channel.


Ross-Elliott TJ, Jensen KH, Haaning KS, Wager BM, Knoblauch J, Howell AH, Mullendore DL, Monteith AG, Paultre D, Yan D, Otero-Perez S, Bourdon M, Sager R, Lee JY, Helariutta Y, Knoblauch M, Oparka KJ (2017) Phloem unloading in Arabidopsis roots is convective and regulated by the phloem-pole pericycle. Elife.

http:/​/​dx.​doi.​org/10.7554/eLife.24125

Open Access

Karl Oparka (University of Edinburgh) is the corresponding author of this study that includes researchers from the UK, US and Denmark. Movement of solutes and macromolecules through the plant phloem is key for the correct distribution of nutrients allowing for optimal growth. In this paper they discover that unloading of molecules from the phloem occurs via a set of specialized funnel plasmodesmata that link the phloem to adjacent pericycle cells. Remarkably they find that whereas solutes are constantly unloaded, larger proteins are released through these plasmodesmata in discrete pulses, which they describe as ‘batch unloading’. Overall this study provides evidence of a major role for the phloem-pericycle cells in the process of moving essential nutrients from the phloem into surrounding tissues.


Moore S, Liu J, Zhang X, Lindsey K (2017) A recovery principle provides insight into auxin pattern control in the Arabidopsis root. Sci Rep. http:/​/​dx.​doi.​org/10.1038/srep43004

Open Access

The work comes from the lab of Keith Lindsey (University of Durham) and developes a data-driven model that predicts the role of auxin patterning in the recovery of an Arabidopsis root following a perturbation of polar auxin transport. They demonstrate three main principles that define the role of auxin influx and efflux carriers in this process and also provide experimental validation for their predictions.


Cai S, Chen G, Wang Y, Huang Y, Marchant B, Wang Y, Yang Q, Dai F, Hills A, Franks PJ, Nevo E, Soltis D, Soltis P, Sessa E, Wolf PG, Xue D, Zhang G, Pogson BJ, Blatt MR, Chen ZH (2017)

Evolutionary Conservation of ABA Signaling for Stomatal Closure in Ferns Plant Physiol

http:/​/​dx.​doi.​org/10.1104/pp.16.01848

Open Access

Mike Blatt (University of Glasgow) is a co-author on this global study that looks into the evolution of ABA-signaling in the control of stomatal closure. Although this study is focused on this process in ferns they build their findings on the analysis of transcriptional networks from Arabidopsis. Ultimately they find that the evolution of ABA-controlled guard cells movements are important in the adaptation of ferns to a terrestrial environment.

Arabidopsis Research Roundup: February 20th

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Published on: February 19, 2017

This weeks Arabidopsis Research Roundup begins with two papers that look at endogenous and exogenous causes of cell proliferation. Firstly Mike Bevan (JIC) leads a team that looks into the role of controlled protein degradation in this process whilst secondly, Peter Etchells from Durham is a co-author on a study that investigates how nematode pathogens stimulate cell proliferation at the site of infection.

Thirdly is work featuring Cyril Zipfel and colleagues from TSL that looks at how autophosphorylation controls the activity of calcium dependent protein kinases. Fourthly is a broad collaboration led by Richard Mott (UCL) that uses genomic structural variation to identify novel loci. Next Simon Turner from the University of Manchester phylogenetically defines the RALK peptide lineages across plant species. Finally researchers at the University of York conduct a structural analysis of the Arabidopsis AtGSTF2 glutathione transferase.


Dong H, Dumenil J, Lu FH, Na L, Vanhaeren H, Naumann C, Klecker M, Prior R, Smith C, McKenzie N, Saalbach G, Chen L, Xia T, Gonzalez N, Seguela M, Inze D, Dissmeyer N, Li Y, Bevan MW (2017) Ubiquitylation activates a peptidase that promotes cleavage and destabilization of its activating E3 ligases and diverse growth regulatory proteins to limit cell proliferation in Arabidopsis.

Genes Dev. http:/​/​dx.​doi.​org/10.1101/gad.292235.116

Open Access


Mike Bevan (John Innes Centre) is the corresponding author of this study that also includes researchers from labs in Belgium, Germany and China. They investigate a fundamental determinant of organ shape, the pattern of cell proliferation that leads to final cell size. They show that two RING E3 ligases activate the DA1 peptidase that in turn affects the stabilization and activity of a range of other proteins including the transcription factors TEOSINTE BRANCED 1/CYCLOIDEA/PCF 15 (TCP15) and TCP22. Overall this results in continued cell proliferation and repression of endoreduplication, which ultimately serves to regulate the timing of the transition from cell proliferation to organ differentiation.

Mike discusses the science surrounding this paper on the GARNet YouTube channel.


Guo X,, Wang J, Gardner M, Fukuda H, Kondo Y, Etchells JP, Wang X, Mitchum MG. Identification of cyst nematode B-type CLE peptides and modulation of the vascular stem cell pathway for feeding cell formation. PLoS Pathog. http:/​/​dx.​doi.​org/10.1371/journal.ppat.1006142

Open Access

Peter Etchells (University of Durham) is a co-author on this US-led study that looks at the effect of nematode-delivered CLE-like peptides on cell growth and how that impacts parasitism. This study has identified a new class of peptides from nematodes that are similar to the plant B-type CLE-like peptide TDIF (tracheary element differentiation inhibitory factor). They show that the nematodes alter the activity of the TDIF-TDR (TDIF receptor)-WOX4 signaling module during infection, whose endogenous function acts during procambial meristem cell proliferation. A variety of mutants involved in this process show reduced infection and leading to the hypothesis that WOX4 is a potential target for nematode CLEs. When exogenous nematode CLE peptides are added to Arabidopsis roots they cause massive cell proliferation. This demonstrates that this response is clearly important for the establishment of nematode infection, usually in cambial cell files.


Bender KW, Blackburn RK, Monaghan J, Derbyshire P, Menke FL, Zipfel C, Goshe MB, Zielinski RE, Huber SC (2017) Autophosphorylation-based calcium (Ca2+) sensitivity priming and Ca2+/Calmodulin inhibition of Arabidopsis thaliana Ca2+-dependent protein kinase 28 (CPK28) J Biol Chem.

http:/​/​dx.​doi.​org/10.1074/jbc.M116.763243

Cyril Zipfel (The Sainsbury Lab) features for a second consecutive week on the Arabidopsis research roundup, this time as a co-author in a study that investigates the role of autophosphorylation in the regulation of calcium (Ca2+) dependent protein kinases (CPKs). In addition they evaluated the role of Calmodulin (CaM) on the activity of CPKs, something that had been previously overlooked. Indeed they show that CPK28 is a CaM-binding protein and that autophosphorylation causes increased activity, especially in low Ca2+ concentrations. Therefore this research provides a mechanistic insight into how a cell might respond to low levels of Ca2+.


Imprialou M, Kahles A, Steffen JG, Osborne EJ, Gan X, Lempe J, Bhomra A, Belfield E, Visscher A, Greenhalgh R, Harberd NP, Goram R, Hein J, Robert-Seilaniantz A, Jones J, Stegle O, Kover P, Tsiantis M, Nordborg M, Rätsch G, Clark RM, Mott R Genomic Rearrangements in Arabidopsis Considered as Quantitative Traits. Genetics. http:/​/​dx.​doi.​org/10.1534/genetics.116.192823

Open Access

Richard Mott (UCL) is corresponding author on this paper includes authors from throughout the UK, Europe and the US. They provide a new analysis of Arabidopsis populations that relies on the genome structural variation. They treat these structural variants as quantitative traits and subsequently map genetically in the same way as in a gene expression study. When a structural variant locus is linked to a genotype at a distant locus then it is designated as a site of transposition. Remarkably they show 25% of the structural variants can be assigned to the transposition events. This method of assessing structural variant loci is amendable to sequencing at low-coverage and this study identified loci that might be involved in germination and resistant to pathogens. Overall they find that genes within structural variants are more likely to be silenced and that this novel analysis technique is particularly useful when mapping transposition events.


Campbell L, Turner SR1(2017) A Comprehensive Analysis of RALF Proteins in Green Plants Suggests There Are Two Distinct Functional Groups. Front Plant Sci. http:/​/​dx.​doi.​org/10.3389/fpls.2017.00037

Open Access

This study from the lab of Simon Turner (University of Manchester) analyse Rapid Alkalinization Factor (RALFs) cysteine-rich peptides from across 51 plant species. They infer that these plant RALFs originate from four major clades in which the majority of the variation exists in the mature peptide sequence, indicative of clade-specific activities. Clade IV accounts for a third of the total peptides yet these lack a number of sequence features thought to be important for RALF function, which leads the authors to speculate that this clade should be thought of as containing RALF-related peptides instead of regular RALFs. Further experimental work is needed in order to define the true nature of the functional relationship between Clades I-III and Clade IV.


Ahmad L, Rylott EL, Bruce NC, Edwards R, Grogan G (2016) Structural evidence for Arabidopsis glutathione transferase AtGSTF2 functioning as a transporter of small organic ligands. FEBS Open Bio. http:/​/​dx.​doi.​org/10.1002/2211-5463.12168

Open Access

This paper links plant science and structural biology in a study that was undertaken at the University of York. Plant Glutathione transferases (GSTs) have multiple roles including in the detoxification of xenobiotics as well as in various non-catalytic roles. In this work the structure of the Arabidopsis AtGSTF2 is revealed in tandem with a variety of non-catalytic partners including indole-3-aldehyde, camalexin, the flavonoid quercetrin and its non-rhamnosylated analogue quercetin. These are thought to bind to AtGSTF2 by hydrophobic interactions at either one or two symmetrical binding sites. The authors speculate that this non-catalytic binding might have a possible role in ligand transport.

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