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.

Stockbridge Technology Centre

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Published on: March 22, 2017

Following the conclusion of the CyVerseUK workshop at the University of York I was delighted to take a brief visit to StockBridge Technology Centre (STC) to have a look at their facilities.

STC are involved in a range of research projects that involve different aspects of plant growth across many conditions and species. As well as initiating independent research projects they are equally at home working with a broad cross section of collaborators and as such sit in an excellent position to make linkages between interest groups who can be challenging to bring together.

STC has received significant public interest for the work they do, with a number of high profile appearances in the mainstream media, most recently in early March on BBC Countryfile (see from 24minutes onward). At their site in the Vale of York they have a large number of highly adaptable greenhouses that sit in alongside 70 hectares appropriate for field trials. In addition they are involved with more technology-facing projects such as the LED4Crops that is run by Dr Phillip Davis at STC.
This project is highly relevant at a time when there are concerns about UK food security and our reliance of imported produce. Use of LED technology is proving extremely useful in improving our understanding of the light regimes that are required in order to both maximise biomass production and improve different traits. This is particularly relevant as there is a growing need to work on a constant 12-month rotation.

Researchers at the LED4Crops facility work with both ornamental and food crops and they are hoping to soon gain funding to greatly expand their operation. If the potential of Stacked Urban Farming is to be realised then the type of research undertaken at STC will be critical for understanding the light conditions needed to maximise production in those sunlight-less environments.

For academic researchers STC sits at an advantageous position of being able to bridge the gap between basic research, industry and farmers and are therefore happy to interact with any potential partners. Although researchers at STC are unable to indepedently apply for RCUK funding they are partners on many grants and work on plenty of EU-funded projects.

Please take a look at the STC website and I’m sure they’d be delighted to host anyone who is interested in visiting their facilities.

Phill Davis will be writing a longer piece for the next issue on the GARNish newsletter so please look out for that!

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.

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