Arabidopsis Research Roundup: July 18th

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Published on: July 18, 2017

This weeks Arabidopsis Research Roundup includes four studies from around the UK. Firstly is a systems-level study of the drought response that includes Alessandra Devoto from RHUL as a co-author. Secondly Anne Osbourn’s group at the JIC investigates sesterterpenoid biosynthesis across plant species. Thirdly Paul Jarvis from Oxford University adds to this groups portfolio of research on the mechanisms that control thylakoid import. Finally Patrick Gallois (University of Manchester) provides further insight into the regulation of programmed cell death.

Kim JM, To TK et al (2017) Acetate-mediated novel survival strategy against drought in plants Nature Plants http:/​/​dx.​doi.​org/10.1038/nplants.2017.97

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Alessandra Devoto (Royal Holloway) is an co-author of this Japanese-led study that investigates the system-wide alterations that plants make in response to drought stress. They demonstrate that the histone deacetylase HDA6 is the primary regulator of an epigenetic switch that leads to a metabolic flux conversion from glycolysis into acetate synthesis. This in turn stimulates the jasmonate signaling pathway that causes increased drought tolerance. Importantly the authors show that this critical survival response is evolutionarily conserved through monocots and dicots.

Alessandra discusses this paper on the GARNet YouTube channel

Huang AC, Kautsar SA, Hong YJ, Medema MH, Bond AD, Tantillo DJ, Osbourn A (2017) Unearthing a sesterterpene biosynthetic repertoire in the Brassicaceae through genome mining reveals convergent evolution. PNAS http:/​/​dx.​doi.​org/10.1073/pnas.1705567114

Open Access

Anne Osbourn (JIC) leads this study in which her group works with collaborators from Cambridge, Wageningen and UC Davis to perform a cross-species genome-wide analysis of sesterterpenoid biosynthesis. They use a novel search algorithm to identify paired enzymatic components that comprise sesterterpene synthases (STS). These enzymes were transiently overexpressed in tobacco leaves, resulting in the formation of fungal-like sesterterpenes, suggestive of convergent evolution of plant and fungal STS. This study illuminates possible future strategies for the beneficial use of sesterterpenes through metabolic and protein engineering

Bédard J, Trösch R, Wu F, Ling Q, Flores-Pérez Ú, Töpel M, Nawaz F, Jarvis P (2017) New Suppressors of the Chloroplast Protein Import Mutant tic40 Reveal a Genetic Link between Protein Import and Thylakoid Biogenesis. Plant Cell. http:/​/​dx.​doi.​org/10.1105/tpc.16.00962 Open Access

Paul Jarvis (Oxford University) leads this global collaboration that focuses on the chloroplast protein import protein Tic40. A suppressor screen identified two novel regulators of Tic40, ALB4 and STIC2 that they postulate are involved in the thylakoid targeting of a subset of proteins and that their influence becomes more important in the absence of Tic40.

Cai YM, Yu J, Ge Y, Mironov A, Gallois P (2017) Two proteases with caspase-3-like activity, cathepsin B and proteasome, antagonistically control ER-stress-induced programmed cell death in Arabidopsis. New Phytol.

http:/​/​dx.​doi.​org/10.1111/nph.14676 Open Access

Patrick Gallois is the corresponding author on this study that originates at the University of Manchester. They attempt to establish a role for cathepsin B and proteasome subunit PBA1 in the control of programmed cell death (PCD) and whether their functions interest with those of caspase-3. They reveal a complex system of regulation where aspects of PCD are differentially impacted by each of these proteins. They propose the role of cathepsin B might occur late in PCD following tonoplast rupture.

Arabidopsis Research Roundup: July 3rd.

The Arabidopsis Research Roundup returns this week with selection of publications from institutions across the UK. Firstly George Bassel (Birmingham) leads a study that investigates the integration of inductive signals in the embryonic root. Secondly a group from the Oxford Brookes plant science group look into the literal linkages between the golgi apparatus and ER. Thirdly John Christie (Glasgow) and co-workers define a new variant of the phototropin receptor. Next Caroline Dean and Martin Howard (John Innes Centre) collaborate on work that defines the relationship between FLC, COOLAIR and cell size. The fifth paper is led by members of SLCU and investigates the regulatory influence of the Evening Complex of the circadian clock. The penultimate paper features work from Alison Smith’s group at the JIC that looks at dynamics of starch accumulation and degradation. Lastly is research from NIAB that defines the pathogeniticity of novel UK isolates of the fungal pathogen Verticillium longisporum.

Topham AT, Taylor RE, Yan D, Nambara E, Johnston IG, Bassel GW (2017) Temperature variability is integrated by a spatially embedded decision-making center to break dormancy in Arabidopsis seeds. PNAS


Open Access

George Bassel (University of Birmingham) leads this study that identifies a decision making centre in the embryonic root that is defined by the intimate interaction between the hormones abscisic acid (ABA) and gibberellin (GA). The activity of this ‘decision centre’ is linked to both hormone transport and changes in temperature, the overall output of which is the decision to promotes seed germination or to delay until more favourable environmental conditions.

George discusses this paper on the GARNet YouTube channel.

Osterrieder A, Sparkes IA, Botchway SW, Ward A, Ketelaar T, de Ruijter N, Hawes C (2017) Stacks off tracks: a role for the golgin AtCASP in plant endoplasmic reticulum-Golgi apparatus tethering. J Exp Bot. http:/​/​dx.​doi.​org/10.1093/jxb/erx167

Open Access

Anne Osterrieder and Chris Hawes (Oxford Brookes University) continue their work that looks at  the cellular dynamics of the golgi apparatus with this study that identifies the AtCASP protein as a important component that tethers the golgi to the ER. They use live-cell imaging to visualise golgi formation in cells that have different levels of AtCASP, allowing the authors to confirm that ER-golgi tethering is disrupted without the activity of this protein.

Petersen J, Inoue SI, Kelly SM, Sullivan S, Kinoshita T, Christie JM (2017) Functional Characterization of a Constitutively Active Kinase Variant of Arabidopsis Phototropin 1

J Biol Chem. http:/​/​dx.​doi.​org/10.1074/jbc.M117.799643

Open Access

John Christie (University of Glasgow) collaborates with Japanese colleagues to identify a novel variant of the phototropin receptor. Study of this variant allows a greater understanding regarding the mode of action of this protein under different light conditions, as controlled by phosphorylation.

Ietswaart R, Rosa S, Wu Z, Dean C, Howard M (2017) Cell-Size-Dependent Transcription of FLC and Its Antisense Long Non-coding RNA COOLAIR Explain Cell-to-Cell Expression Variation. Cell Syst. http:/​/​dx.​doi.​org/10.1016/j.cels.2017.05.010

Open Access

Martin Howard and Caroline Dean (John Innes Centre) again collaborate on research that analyses the mode of regulation of FLC. They dissect RNA dynamics of FLC expression by single molecule in situ RNA fluorescence, showing that this is dependent on the presence of the antisense COOLAIR regulatory DNA. In the absence of COOLAIR they show FLC expression has a linear relationship with cell size but in the presence of the antisense transcript, FLC expression decreases with cell size. Overall they demonstrate FLC expression is tightly dependent on the presence of the antisense COOLAIR transcript.

Ezer D, Jung JH, Lan H, Biswas S, Gregoire L, Box MS, Charoensawan V,, Cortijo S, Lai X,, Stöckle D, Zubieta C, Jaeger KE, Wigge PA (2017) The evening complex coordinates environmental and endogenous signals in Arabidopsis. Nat Plants.


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Phil Wigge and Katja Jaeger (SLCU) lead this study that investigates how the evening complex of the circadian clock coordinates the expression of numerous important growth regulators. This genome wide regulation is determined by temperature and concides with the binding of phytochrome B, which provides a cellularly mechanism of this level of environmental control.

Fernandez O, Ishihara H, George GM, Mengin V, Flis A, Sumner D, Arrivault S, Feil R, Lunn JE, Zeeman SC, Smith AM, Stitt M (2017) Foliar starch turnover occurs in long days and in falling light at the end of the day. Plant Physiol. http:/​/​dx.​doi.​org/10.1104/pp.17.00601

Open Access

On this paper Alison Smith (John Innes Centre) is a co-corresponding author together with Mark Stitt from the Max Planck Institute for Molecular Plant Physiology in Potsdam. They continue their work to investigate the dynamics of starch metabolism in Arabidopsis leaves. Broadly they show the rate of starch accumulation corresponds to the photosynthetic rate whilst degradation is linked to correct functioning of the circadian clock. They investigate this process in more detail by determining how the rate of starch degradation alters dependent on the time after dawn.

Depotter J, Rodriguez-Moreno L, Thomma BP, Wood T (2017) The emerging British Verticillium longisporum population consists of aggressive Brassica pathogens. Phytopathology http:/​/​dx.​doi.​org/10.1094/PHYTO-05-17-0184-R

Tom Wood (NIAB) is the corresponding author of this study that characterises four new UK isolates of the fungal pathogen Verticillium longisporum. The pathogenticity of V.longisporum was tested on Arabidopsis alongside three other Brassica crops. They demonstrate that the UK isolates were unusually aggressive yet this was not consistent across all Brassica cultivars with different fungal lineages showing different effects on oil seed rape, cabbage or cauliflower.

Arabidopsis Research Roundup: May 17th

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Published on: May 17, 2017

This weeks Arabidopsis research roundup begins with a paper led by CPIB at the University of Nottingham that discovers a somewhat surprisingly mechanism controling Arabidopsis root hydrotropism. Next are two papers from the University of Leeds that firstly investigate how the JAGGED LATERAL ORGANS gene influences the auxin response and secondly looks at the role of redox regulation in the control of the cell cycle and seed development. Finally are two papers that look at different aspects of the plant pathogen interactions. Jonathan Jones from the John Innes Centre is a co-author on a paper that dissects the multiple gene expression networks that control plant immunity whilst Charles Melnyk at the Sainsbury lab in Cambridge is involved with work that investigates the hormonal control mechanisms that influence the invasion of parasitic plants.

Dietrich D, Pang L, Kobayashi A, Fozard JA, Boudolf V, Bhosale R, Antoni R, Nguyen T, Hiratsuka S, Fujii N, Miyazawa Y, Bae TW, Wells DM,, Owen MR,, Band LR,, Dyson RJ, Jensen OE, King JR, Tracy SR, Sturrock CJ,, Mooney SJ, Roberts JA, Bhalerao RP, Dinneny JR, Rodriguez PL, Nagatani A, Hosokawa Y, Baskin TI, Pridmore TP, De Veylder L, Takahashi H, Bennett MJ (2017) Root hydrotropism is controlled via a cortex-specific growth mechanism. Nature Plants


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Malcolm Bennett (University of Nottingham) leads a broad international collaboration that looks at the response of Arabidopsis roots to water. Surprisingly they show that this response occurs not in the root meristem but in the elongation zone and is controlled by a ABA signaling mechanism. They show that hydrotropism is dependent on cell elongation in the cortex but not in any other cell file. This is different to the gravitropic response and demonstrates that these tropisms are controlled by distinct tissue-specific mechanisms. To provide for information about this paper, lead author Daniela Dietrich joins Professor Bennett to discuss this paper on the GARNet YouTube channel and speculate on the function of different root cell layers in water uptake.

Rast-Somssich MI, Žádníková P, Schmid S, Kieffer M, Kepinski S, Simon R (2017) The Arabidopsis JAGGED LATERAL ORGANS (JLO) gene sensitizes plants to auxin. J Exp Bot.

http:/​/​dx.​doi.​org/10.1093/jxb/erx131 Open Access

This German-led study includes Stefan Kepinski (University of Leeds) as a co-author. They investigate the role of the JAGGED LATERAL ORGANS (JLO) transcription factor in the establishment of the stem cell niche in the root meristem. JLO interacts with auxin signaling pathway by influencing the degradation of the key regulator BODENLOS (BDL) via the TIR1-mediated degradation pathway. In jlo mutants BDL remains present in the meristem, which does not correctly develop. They discover a novel regulatory mechanism wherein the dosage of the TIR1 and AFB1 auxin receptors is reduced, which in turn prevents BDL degradation. This shows that the JLO transcription factor is a key upstream regulator of meristem formation by playing a significant role in the fine control of the auxin response.

De Simone A, Hubbard R, Vinegra de la Torre N, Velappan Y, Wilson M, Considine MJ, Soppe W, Foyer CH (2017) Redox changes during the cell cycle in the embryonic root meristem of Arabidopsis thaliana. Antioxid Redox Signal. http:/​/​dx.​doi.​org/10.1089/ars.2016.6959

Open Access

Christine Foyer (University of Leeds) collaborates with Australian and German researchers to unpick the role that redox regulation plays in the control of the plant cell cycle. They use an in vivo redox reporter (roGFP2) to show that a cycle of reduction and oxidation occurs throughout the cell cycle. Their experimental system is Arabidopsis seed germination and they show that vitamin c defective mutants with low redox buffering capacity have altered germination rates that coincide with a changed dry seed transcriptome. Overall this paper demonstrates that the cell cycle and embryo size are linked to redox regulation.

Hillmer RA, Tsuda K, Rallapalli G, Asai S, Truman W, Papke MD, Sakakibara H, Jones JDG, Myers CL, Katagiri F (2017) The highly buffered Arabidopsis immune signaling network conceals the functions of its components. PLoS Genet. http:/​/​dx.​doi.​org/10.1371/journal.pgen.1006639

Open Access

Jonathan Jones (John Innes Centre) is a co-author on this Japanese-led research that studies the signaling networks invovled in plant immunity. They use a systems biology approach to dissect the network of interactions that occur within the transcriptome when plants are exposed to the immune stimulant flagellin-22. This analysis discovers that there are separated networks that represent pathways controlled by different higher-level signals, such as jasmonate or salicylic acid. This provides the entire network with a degree of buffering that allows a more effective response to pathogen attack. This type of network analysis is able to reveal facets of the defence response that would not be possible when using simple null mutant analysis so adds consideration detail to the already complicated story of plant-pathogen interactions

Spallek T, Melnyk CW, Wakatake T, Zhang J, Sakamoto Y, Kiba T, Yoshida S, Matsunaga S, Sakakibara H, Shirasu K (2017) Interspecies hormonal control of host root morphology by parasitic plants. PNAS


Charles Melnyk (Sainsbury Lab, Cambridge) is an author on this study led by Ken Shirasu at RIKEN and uses Arabidopsis to investigate the relationship between parasitic plants and their hosts, specifically at the level of interspecies transport via a structure called the haustorium. Haustoria are structures through which substances, such as RNA and proteins, reciprocally move between host and parasite. In this paper they look at the interaction between Arabidopsis roots and the hemiparasitic plant Phtheirospermum japonicum, demonstrating that movement of molecules between species occurs via haustoria once a vascular connection is made. Arabidopsis secondary root growth is induced under infection, a response that requires the effect of the hormone cytokinin. They look at the genetics of this interaction and show that cytokinin signaling genes are important in establishing root hypertrophy. Overall this study demonstrates the important of cytokinin during infection with parasitic plants and might be an important target to design strategies to combat these negative interactions in systems.

Arabdopsis Research Roundup: May 11th

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Published on: May 11, 2017

This weeks Arabidopsis Research Roundup is lead by two papers that characterise the relationship between cell size and growth in different Arabidopsis tissues. Firstly the lab of GARNet PI Jim Murray look at how the cell cycle influences cell size progression in the SAM whilst George Bassel’s group from Birmingham investigate cell growth within a developing embryo. Thirdly is a paper from the University of Essex that further defines the role of the CP12 protein in control of photosynthesis. Next is a paper from researchers from the University of Warwick who lead a fascinating piece of rocket science that identifies differences in the vernalisation requirement across Brassica species whilst in the fifth paper, researchers from Lancaster identify environmentally defined QTLs that determine the plant response to glutamate. Finally is a paper that highlights a new software tool that has the self-explanatory title of the ‘UEA small RNA Workbench’ and is applicable for use with plant-derived datasets.

R Jones A, Forero-Vargas M, Withers SP, Smith RS, Traas J, Dewitte W, Murray JAH (2017) Cell-size dependent progression of the cell cycle creates homeostasis and flexibility of plant cell size. Nat Commun http:/​/​dx.​doi.​org/10.1038/ncomms15060

Open Access

This study comes from the lab of current GARNet PI Jim Murray at the Cardiff University. Lead author Angharad Jones kindly provides an audio description of the paper for the GARNet YouTube channel. This  investigation looks at the factors that control the interaction between cell size and cell growth in a developing shoot meristem. They show that the dynamic regulation of this relationship is linked to the activity of two cyclin dependent kinases (CDKs) and that cell size is key in controlling the transition from G1>S and from G2>M phases of the cell cycle. Importantly this work uses precise imaging to track the progression of individual cell lineages and is therefore able to suggest that cell size is an emergent and not a directly determined property.

Souza NM, Topham AT, Bassel GW (2017) Quantitative analysis of the 3D cell shape changes driving soybean germination. J Exp Bot. http:/​/​dx.​doi.​org/10.1093/jxb/erx048

Open Access

George Bassel (University of Birmingham) leads this paper that uses information gained from the study of patterns of cell expansion in Arabidopsis embryos to investigate a similar process in soybean. Indeed as in Arabidopsis they show that there is preferential early cell expansion closest to the soybean radicle and that starting cell size corresponds to different growth rates. In addition they show that the growing hypocotyl has complex regulation and that differential ansiotrophy growth drives forward the process of germination. Ultimately they show that this occurs equivalently in both model and crop species.

Elena López-Calcagno P, Omar Abuzaid A, Lawson T, Anne Raines C (2017) Arabidopsis CP12 mutants have reduced levels of phosphoribulokinase and impaired function of the Calvin-Benson cycle. J Exp Bot http:/​/​dx.​doi.​org/10.1093/jxb/erx084 Open Access
This study from the photosynthesis group at the University of Essex is led by Tracey Lawson and GARNet committee member Christine Raines. They investigate the role of the CP12 multigene family that has three members in Arabidopsis. These are redox-sensitive proteins that facilitate the formation of a complex between glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and phosphoribulokinase (PRK) during the Calvin-Benson cycle. They show that plants with reduced levels of CP12-1 or CP12-2 have lower photosynthetic capacity and subsequently exhibit slower growth. The cell biological explanation for this alteration appears to focus on the PRK protein, which is present at lower levels in plants with reduced CP12-1 or CP12-2. Therefore the authors find that CP12-1 and CP12-2 are the key members of this gene family and they likely show functional redundancy in the tight control of photosynthesis.

Taylor JL, Massiah A, Kennedy S, Hong Y, Jackson SD (2017) FLC expression is down-regulated by cold treatment in Diplotaxis tenuifolia (wild rocket), but flowering time is unaffected. J Plant Physiol.

http:/​/​dx.​doi.​org/10.1016/j.jplph.2017.03.015 Open Access
Steve Jackson (University of Warwick) leads this work that also features Chinese collaborators and investigates the role of FLOWERING LOCUS C (FLC) in the popular peppery salad plant Rocket (Diplotaxis tenuifolia) that, as a Brassica, is a somewhat closely related to Arabdopsis. The authors studied the vernalisation requirement in this plant so isolated its version of FLC, which was shown to functional compliment an Arabidopsis flc null mutant. However they showed that even though cold treatment reduced levels of DtFLC this did not alter the bolting time of the plant. This somewhat surprising result demonstrates that the link between FLC and flowering time is uncoupled in this species and that other mechanisms may take precedence, a situation different to that observed in Arabidopsis and other Brassicas.

Walch-Liu P, Meyer RC, Altmann T, Forde BG (2017) QTL analysis of the developmental response to L-glutamate in Arabidopsis roots and its genotype-by-environment interactions. J Exp Bot.

http:/​/​dx.​doi.​org/10.1093/jxb/erx132 Open Access Researchers from the groups of Brian Forde (Lancaster University) and Thomas Altmann (Leibniz Institute) collaborate in this research that identifies three novel QTLs (GluS1-3) that are involved in the response of Arabdopsis roots to external L-glutamate. When this experiment was extended they discovered that different environmental factors play a significant role in the control of this trait. The GluS1 locus is located on Chr3 yet is epistatically controlled by loci on Chr1 and Chr5 in response to temperatures. Overall this study demonstrates that the response to glutamate is controlled by multiple environmentally sensitive loci that vary between Arabidopsis ecotypes

Mohorianu I, Stocks MB, Applegate CS, Folkes L, Moulton V (2017) The UEA Small RNA Workbench: A Suite of Computational Tools for Small RNA Analysis. Methods Mol Biol.


This manuscript from the University of East Anglia describes a set of software tools for the analysis of small RNAs. They used an Arabidopsis dataset to demonstrate the utility of the UEA small RNA Workbench, which can be found here:

Arabidopsis Research Roundup: March 31st.

This bumper edition of the Arabidopsis Research Roundup includes a wide range of research topics. Firstly Mike Roberts leads a study that adds another layer of complexity to our understanding of the factors that control seed dormancy. Secondly a paper from Ottoline Leyser’s lab at SLCU provides more details regarding the role of BRC1 during shoot branching. Next is a paper that continues David Salt’s collaborative work that aims to understand how the root endodermal barrier influences nutrient uptake. Fourthly is work from Bristol that looks at the interaction between viral infection, the structure of the leaf surface and the polarization of reflected light. The fifth paper features a wide collaboration from the Sainsbury lab in Norwich and aims to more fully understand the factors that lead to non-host infection by Phytophthora infestans. The penultimate paper looks at the interaction of aldolase enzymes with the plant actin cytoskeleton and the final paper brings us full circle back to seed dormancy where researchers from University of Warwick investigate the link between this complex growth response and the circadian clock.

Singh P, Dave A, Vaistij FE, Worrall D, Holroyd GH, Wells JG, Kaminski F, Graham IA, Roberts MR (2017) Jasmonic acid-dependent regulation of seed dormancy following maternal herbivory in Arabidopsis. New Phytol http:/​/​dx.​doi.​org/10.1111/nph.14525

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Open Access

Mike Roberts (University of Lancaster) kindly provides an audio description of this paper on the GARNet YouTube channel, explaining that, in collaboration with Ian Graham at the University of York, they have identified a new control mechanism that links jasmonic acid, herbivory and seed dormancy. ABA and GA are known to be important hormones in the control of seed dormancy but this study adds complexity to this story by showing that following herbivory (or leaf wounding), the level of JA increases within Arabidopsis seeds. Perhaps counter-intuitively, in the following generation this leads to a reduction in dormancy, causing seed to germinate sooner than those from non-predated parents. The authors show that this is due to an increase in JA within seeds that importantly also alters sensitivity to ABA. Unlike transgenerational defence priming that acts through a epigenetic mechanism and persists for multiple generations , this study shows that the JA effect on seeds is a more direct response. Ultimately the mechanism in which parents prepare their offspring for subsequent generations is a complex trade off between multiple sources of predation and pathogenesis, environmental factors as well as through the effect of interacting hormone signaling pathways.

Seale M, Bennett T, Leyser O (2017) BRC1 expression regulates bud activation potential, but is not necessary or sufficient for bud growth inhibition in Arabidopsis. Development http:/​/​dx.​doi.​org/10.1242/dev.145649 Open Access

This is the latest contribution from Ottoline Leyser’s lab that looks into the hormonal control of shoot branching. A key determinant of this process is the transcription factor, BRANCHED1 (BRC1) yet this study shows that under certain conditions, in this case with varied amount of strigolactone, the controlling effect of BRC1 expression levels can be mitigated. The authors provide evidence for a mechanism for branching control that involves the coordinated activity of BRC1 and an auxin-transport mechanism, both of which are influenced by a separate strigolactone-mediated signaling pathway.

Li B, Kamiya T, Kalmbach L, Yamagami M, Yamaguchi K, Shigenobu S, Sawa S, Danku JM, Salt DE, Geldner N, Fujiwara T (2017) Role of LOTR1 in Nutrient Transport through Organization of Spatial Distribution of Root Endodermal Barriers. Current Biology


Former GARNet chairman David Salt is a co-author on this paper that is lead by Japanese and Swiss colleagues and continues his work on the development of the casparian strip. These rings of lignin polymers are deposited within root endodermal cells and play a key role in the movement of water and nutrients into the vascular tissue. Suberin lamellae have a similar function and surround endodermal cells, likely acting as a barrier to apoplastic movement. This paper documents the identification of the Tolkienesquely-named LOTR1, which is essential for casparian strip formation. Lotr1 mutants show disrupted casparian strips, ectopic suberization and reduced calcium accumulation in the shoot. Further analysis demonstrates that it is this suberized layer substitutes for the CS in regions of lateral root emergence. Utliamtely they show that the relationship between suberization of the endodermal layer is a key determinant of calcium movement into the root and then around the rest of the plant.

Maxwell DJ, Partridge JC, Roberts NW, Boonham N, Foster GD (2017) The effects of surface structure mutations in Arabidopsis thaliana on the polarization of reflections from virus-infected leaves. PLoS One

http:/​/​dx.​doi.​org/10.1371/journal.pone.0174014.g003 Open Access

Gary Foster (University of Bristol) leads this study that continues his labs work on the effect that viral infection has on light polarization when reflected off leaves. This attribute is important to attract insect predators, which in turn increase the possibility of successful viral transmission. Light polarization is affected by structures on the leaf surface such as trichomes or the makeup of the waxy cuticle. Here the authors show that the cer5 wax synthesis mutant alters the polarization of light following infection with Turnip vein clearing virus (TVCV) but not following infection with Cucumber mosaic virus (CMV). The paper provides no mechanism for this difference but the authors do show that leaf viral titre is equivalent in these mutants and therefore speculate that these changes might influence transmission of each virus by a different insect carrier that in turn responses to different patterns of polarized light.

Prince DC, Rallapalli G, Xu D, Schoonbeek HJ, Çevik V,, Asai S,, Kemen E,, Cruz-Mireles N, Kemen A,, Belhaj K, Schornack S,, Kamoun S, Holub EB, Halkier BA, Jones JD (2017) Albugo-imposed changes to tryptophan-derived antimicrobial metabolite biosynthesis may contribute to suppression of non-host resistance to Phytophthora infestans in Arabidopsis thaliana. BMC Biol. 

http:/​/​dx.​doi.​org/10.1186/s12915-017-0360-z  Open Access

This paper is a wide collaboration that features many colleagues from the Sainsbury lab in Norwich. Wildtype Arabidopsis plants are suspectible to Phytophthora infestans only after earlier infection with Albugo laibachii yet the molecular explanation of this complex interaction between plant and microbes remained opaque. This study demonstrates that Albugo infection alters the levels of a set of tryptophan-derived antimicrobial compounds, which were then found to be relevant for infection with P.infestans. This shows that these antimicrobial compounds might be key for the general maintenance of non-host resistance and might provide important information to aid future strategies to improve food security by reducing biomass loss due to plant pathogens.

Garagounis C, Kostaki KI, Hawkins TJ, Cummins I, Fricker MD, Hussey PJ, Hetherington AM2, Sweetlove LJ (2017) Microcompartmentation of cytosolic aldolase by interaction with the actin cytoskeleton in Arabidopsis. J Exp Bot.


This collaboration between the Universities of Oxford, Bristol and Durham looks into the functional role that molecular microcompartments play in the workings of a cell. Animal models have shown that certain aldolase enzymes are able to function as actin-bundling proteins and so this study focuses on a major plant cytosolic aldolase, FBA8, which is predicted to have two actin binding sites. Although the authors could not detect co-localisation of FBA8-RFP with the actin cytoskeleton they provide in vitro evidence that FBA8 can functionally interact with F-actin. In addition in fba8 mutants there is altered arrangement of actin filaments in guard cells that concomitantly results in a reduced rate of stomatal closure. Therefore these findings leads the authors to propose that FBA8 is able to subtly interact with actin in vivo, evidenced by some FRET-FLIM experiments, and that this may modulate actin dependent cell responses.

Footitt S, Ölcer-Footitt H, Hambidge AJ, Finch-Savage WE (2017) A laboratory simulation of Arabidopsis seed dormancy cycling provides new insight into its regulation by clock genes and the dormancy-related genes DOG1, MFT, CIPK23 and PHYA. Plant Cell Environ http:/​/​dx.​doi.​org/10.1111/pce.12940

William Savage-Finch (University of Warwick) is the corresponding author on this paper that investigates mechanisms that control seed dormancy, which has been built from the analysis of a variety of genetic and environmental factors. They test their predictions by testing a range of mutants in both known dormancy related genes and in the function of the circadian clock. This provides a link between the circadian cycle and the daily variation in the level of seed dormancy in Arabidopsis.

Arabidopsis Research Roundup: March 17th

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Published on: March 17, 2017

This weeks UK Arabidopsis Research Roundup includes three papers featuring researchers from the University of Nottingham as well as manuscripts from Leeds, Lancaster, QMUL and The Sainsburys Lab in Norwich

Firstly Stefan Kepinski (Leeds) leads a study that investigates how Gravitropic Set Point Angle (GSA) is controlled in response to different growth factors. Secondly are two Methods papers featuring researchers from CPIB in Nottingham, the first of which is in collaboration with Lancaster University and introduces the Microphentron, which is an automated phenotyping platform that can be used for chemical biology screens. The second paper describes a non-destructive method for imaging floral tissues using CT scanning.

Ranjan Swarup is also a member of CPIB and in the next paper he has collaborated with French colleagues to investigate the role of SHR on root development in rice.

The fourth paper includes Cyril Zipfel as a co-author and investigates the role of damage-associated molecular patterns (DAMPs) in the response to pathogen attack whereas this weeks final paper is from the lab of Alexander Ruban (QMUL) and discovers the phenotypic consequences of persistent damage to PSII by photoinhibition.

Suruchi Roychoudhry, Martin Kieffer, Marta Del Bianco, Che-Yang Liao, Dolf Weijers Stefan Kepinski (2017) The developmental and environmental regulation of gravitropic setpoint angle in Arabidopsis and bean Scientific Reports

Open Access

Stefan Kepinski (University of Leeds) leads this study that involves a collaboration with Dolf Weijers from Wageningen University. They investigate the role of both auxin and environmental factors in determining gravitropic set point angle (GSA), which is a measure of the growth of lateral organs away from primary shoots and roots. They show that nitrogen and phosphorous deficiency causes opposing effects on lateral root GSA, each of which are auxin-dependent. This contrasts with previous findings from work using bean adventitious roots. They find that these differences are maintained when Arabidopsis and bean roots are treated with different auxin concentrations. Latterly they also look at the effect of different light conditions on shoot GSA and put these findings into the context of potentially altering crop growth.

Stefan takes some time to discuss this paper for the GARNet YouTube Channel.

Burrell T, Fozard S, Holroyd GH, French AP, Pound MP, Bigley CJ, James Taylor C, Forde BG (2017) The Microphenotron: a robotic miniaturized plant phenotyping platform with diverse applications in chemical biology. Plant Methods Open Access

This methods paper is a collaboration between the Universities of Lancaster and Nottingham led by Brian Forde that describes the Microphenotron. This device has been developed to facilitate chemical biology screens on in vivo plant tissues. This allows for the automated screening of either dicot or monocot roots or aerial tissues that have been grown on media infused with whichever chemical is relevant for the intended expriments. In situ GUS screening is also possible allowing for researchers to integrate information about growth and gene expression. The use of ‘Phytostrips’ in a 96-well format allows for high-throughput screening that is aligned with AutoRoot automated image analysis software to provide a rapid and facile method for undertaking small scale phenotypic screens. The Microphenotron facility is housed at the Lancester University, who are extremely open to collaboration so please get in contact if you are interested in using the facility.

Tracy SR, Gómez JF, Sturrock CJ, Wilson ZA, Ferguson AC (2017) Non-destructive determination of floral staging in cereals using X-ray micro computed tomography (µCT) Plant Methods. Open Access

Alison Ferguson is the corresponding author on this methods paper that includes GARNet committee member Zoe Wilson and Saoirse Tracy from Dublin. They have developed a technique using X-ray µCT scanning to image developing flowers in Arabidopsis and barley plants, taking advantage of the excellent Hounsfield facility at the University of Nottingham. They show that the technique can be hugely beneficial for plant phenotyping by providing a non-destructive method of analyzing live floral development and how this can response to changes in the growth environment. Members of the Hounsfield facility are happy to discuss any potential collaborative work and future access to these type of facilities will hopefully be improved through the UKs involvement in the pan-european EMPHASIS project.

Henry S, Dievart A, Fanchon D, Pauluzzi G, Meynard D, Swarup R, Wu S, Lee CM, Gallagher K, Périn C (2017) SHR overexpression induces the formation of supernumerary cell layers with cortex cell identity in rice. Dev Biol.

Ranjan Swarup (CPIB) is a co-author on this study that includes French and US researchers. Previously they had shown that expression of rice SHORTROOT (OsSHR) genes could compliment the Arabidopsis shr mutant. In this study they show that overexpression of OsSHR and AtSHR in rice roots causes growth of wider, shorter roots that have an increased number of cortical cell layers. This demonstrates that the mechanisms that control the differentiation of cortical cell layers is conserved throughout land plants, with SHR being a key determinant in this process.

de Azevedo Souza C, Li S, Lin AZ, Boutrot F, Grossmann G, Zipfel C, Somerville S (2017) Cellulose-derived oligomers act as damage-associated molecular patterns and trigger defense-like responses. Plant Physiol.

Cyril Zipfel (The Sainsbury Lab) is a co-author on this study from the lab of Shauna Somerville in California that focuses on the concept of damage-associated molecular patterns (DAMPs). These can be defined as cell wall breakdown components and stimulate the same defence responses as more fully characterised pathogen- or microbe-associated molecular patterns (PAMPs). Intuitively this makes sense as during infection many pathogens will cause cell wall breakdown. The authors show that cellulose-derived oligomers trigger a signalling response similar to that caused by oligogalacturonides or chito-oligomers but that lacks an increase in ROS or in callose deposition. These results confirm that cellulose-derived signals feed into the plants mechanism for cell wall scanning and acts synergistically with other signals that result from pathogen attack.

Tian Y, Ungerer P, Zhang H, Ruban AV (2017) Direct impact of the sustained decline in the photosystem II efficiency upon plant productivity at different developmental stages. J Plant Physiol.

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Alexander Ruban (QMUL) leads this Sino-UK collaboration that investigates how the photoinhibiton of photosystem II impacts overall plant growth. In this study they use lincomycin to block chloroplast protein synthesis, which prevents the plant from restoring PSII function after photoinhibitory damage. Treated plants accumulate less starch and showed reduced above-ground biomass. This leads to a decrease in seed yield. Perhaps unsurprisingly this research shows that restoring the full function of PSII after photoinhibition to key to maintaining normally functioning electron transport rate that leads into metabolic production and growth rate.

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


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.


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


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 27th

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Published on: February 28, 2017

This weeks research roundup includes just three papers and includes a study from the University of Essex that looks at the growth response of Arabidopsis plants to ‘real-life’ fluctuations in light levels. Secondly is a very different type of study from the University of York that uses Arabidopsis as a model for the development of plants that are able to accumulate catalytically active and commercially viable levels of palladium. Finally is a Chinese-led study that includes Alan Marchant (University of Southampton) as a co-author and looks at the role of the ERF74-RbohD-ROS signaling module on the response to abiotics stress.

Vialet-Chabrand SR, Matthews JS, Simkin A, Raines CA, Lawson T (2017) Importance of fluctuations in light on plant photosynthetic acclimation Plant Physiol.

Open Access

Tracy Lawson and GARNet committee member Christine Raines from the University of Essex Photosynthesis Group lead this study that aims to understand how plants respond to variation in light levels that occur over an ‘average’ day. This contrasts with the conditions used in a ‘standard’ growth chamber and they show that plant growth is significantly altered when the light levels fluctuate, even though the total amount of light that the plant receives is the same. The ultimate conclusion of the study is that the growth of plants under ‘square wave growth conditions’ does not accurately reflect what might be observed in the field. This is significant given the importance of moving research from model organisms, usually grown under controlled conditions into crop species grown in the field.

Tracy Lawson kindly takes less than ten minutes to discuss the paper with GARNet on our YouTube channel.

Harumain ZA, Parker HL, Muñoz García A, Austin MJ, McElroy CR, Hunt AJ, Clark JH, Meech JA, Anderson CW, Ciacci L, Graedel TE, Bruce NC, Rylott EL (2017) Towards financially viable phytoextraction and production of plant-based palladium catalysts. Environ Sci Technol. 10.1021/acs.est.6b04821

Open Access

Elizabeth Rylott and Neil Bruce at the University of York lead this study that includes collaborators from the USA, Canada, Malaysia and New Zealand. They look into the options for phytoextraction of palladium, which forms nanoparticles in Arabidopsis roots. The metal taken from these roots had normal catalytic activity and could be obtained at up to 18g/kg dried tissue weight. These experiments were moved into mustard, miscanthus and sixteen willow species and although palladium can be taken up into the plant tissues, it could not be extracted at a level that would make it commercially viable. However the authors are confident that this is am important step toward attempts to develop field-suitable plants that can reduce the environmental impacts of palladium mining.

Yao Y,, He RJ, Xie QL,, Zhao XH,, Deng XM,, He JB,, Song L, He J, Marchant A, Chen XY,, Wu AM (2016) ETHYLENE RESPONSE FACTOR 74 (ERF74) plays an essential role in controlling a respiratory burst oxidase homolog D (RbohD)-dependent mechanism in response to different stresses in Arabidopsis. New Phytol. 213(4):1667-1681.

Alan Marchant (University of Southampton) is a co-author on this Chinese-led study that focuses on the role of the ERF74 transcription factor from the ETHYLENE RESPONSE FACTOR VII (ERF-VII) family in the response to abiotic stresses. The authors test the responses of plants with changed levels of ERF74, showing that they have altered responses to a range of stresses such as drought, light, heat and aluminum. erf74 mutants lack a typical reactive oxidative stress (ROS) burst due to low expression of the RESPIRATORY BURST OXIDASE HOMOLOG D (RbohD) protein. ERF74 directly interacts with the RbohD promotor and the paper shows that the whole ERF74-RbohD-ROS signaling module is activated in order for the plant to correctly response to a range of stresses, which each require maintenance of hydrogen peroxide homeostasis.

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