Enrique Lopez-Juez (RHUL) talks to GARNet

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Published on: January 17, 2018

Enrique Lopez-Juez (Royal Holloway University of London) introduces a paper from that attempts to answer a critical question in plant science ‘Why do plants makes leaves in the dark‘?

http://www.plantphysiol.org/content/early/2017/12/28/pp.17.01730.long

 

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.

Magnetising Pollen to break the Plant Transformation Bottleneck?

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Published on: December 19, 2017

The potential for crop improvement by ‘traditional’ genetic modification and by ‘game-changing’ gene-editing technologies is easy to appreciate. The introduction a foreign gene or the alteration of endogenous gene function in order to modify the way in which a plant responds to a particular environmental stimuli is the underlying goal of most applied plant scientists. Our improved knowledge of how these techniques work, advances in the speed and cost DNA synthesis alongside the adoption of the principles of synthetic biology in the engineering of molecular constructs means that generation of DNA parts for genetic modification is, in theory at least, now facile endeavor.


However there is an ‘eleplant in the room’ of every grant proposal that promises to generate an altered variety of any desired orphan crop. Our ‘eleplant’ is the efficiency, or lack thereof, in plant transformation. This issue was the topic of a 2016 Perspective piece in The Plant Cell in which the example of Sorghum was cited, an important food crop that is unfortunately recalcitrant to transformation, taking up to 12months to generate T1 transformants. This bottleneck will continue to be an issue when discussing new targets for genetic modification as callus-based mechanisms of transformation are famously extremely challenging, with one method good for the goose might be not so good for the gander.

From http://www.plantcell.org/content/28/7/1510

These challenges have been solved for many major crops but even with this knowledge, regeneration of transgenic crops only usually takes place in labs with specific knowledge and experimental pipelines (in the UK at facilities at NIAB or the JIC)*.


It is in this climate that a recent paper by Zhao et al in Nature Plants might be another true game changer. They have modified the magnetofection procedure that has been used very successfully to introduce DNA into animal cells in order to modify existing pollen transformation techniques. This protocol involves mixing DNA with magnetic nanoparticles that can be introduced using a magnetic field into pollen grains through small apertures in the pollen wall. These transformed pollen can then be used to fertilise emasculated plants as normal, from which transgenic seeds can then be selected in the usual manner.

From https://www.nature.com/articles/s41477-017-0072-y

This technique relies upon the pollen aperature being greater than 5um and Zhao et al demonstrate that this was possible in a range of flowering plants including pepper, pumpkin, zucchini and lily. The majority of their experimental work highlighted the introduction of a gene expressing BT toxin into cotton and the subsequent identification of insect resistant plants. The viability of magnetotransformed pollen was unaffected and after the initial fertilization the transgene segregated with normal mendelian ratios.


Importantly for future uptake of this technology, the authors were able to successfully transform Elite varieties that are recalcitrant to callus-transformation, thus greatly reducing the time usually needed for crossing between easily transformable and elite lines. Success rates even for floral dip transformation are lower than 1% so the reported 2-10% in this study, over three years of experiments, strongly suggests that this technique has enormous potential for crop genetic modification.

The only minor drawback is that due to the high success rate, extra generations of selfing transgenic plants might be necessary to obtain pure breeding lines due to the integration of multiple independent insertions.

These experiments have been conducted with a single research lab so it remains to be seen whether these success rates are recapitulated in other locations that have similar but potential significant alterations in their experimental setup.


Importantly the authors do not attempt to use this technique to transform any grass species, a taxonomic group that supplies the vast majority of global animal calories. This will be important to ascertain yet might prove challenging or impossible due to the size of grass pollen grains. Only time will tell whether this is possible.

There is little doubt that this work will raise significant interest in academic and industrial labs across the globe.

Watch this space whether this will prove the breaking of the transformation bottle(neck).

*- Of course Arabidopsis is immune from such concerns as it can be transformed by floral dip, due to an unusually open gynoecium during development.

A commentary article on the Zhao et al paper is also available in Nature Plants.

Arabidopsis Research Roundup: December 18th

This festive Arabidopsis Research Roundup begins with a commentary article from a global consortium of plant scientists who propose a framework of future training for researchers who will take advantage of the experimental tools available in Arabidopsis. Secondly is study from Caroline Dean (JIC) that defines the role of the LHP1 protein in epigenetic control of gene expression. Thirdly John Doonan (Aberystwyth) is a co-author of work that defines an important component of mitotic spindle formation. Next is a study led by Zinnia Gonzalez-Carranza in Nottingham that offers further insights into the function of the HWS gene. The fifth study comes from the lab of Alexander Ruban (QMUL), further investigating the importance of NPQ in photosynthetic control. The sixth paper from the Van Ooijen lab (Edinburgh) characterises the role of sumoylation in the control of CCA1 activity. The penultimate paper from the Harberd lab in Oxford defines the importance of DNA mismatch repair on genome sequence integrity whilst the final paper characterises the next phase in the long story of Arabidopsis ALF4 function and includes Charles Melynk (SLCU) as a co-author.


Friesner J et al (2017) The Next Generation of Training for Arabidopsis Researchers: Bioinformatics and Quantitative Biology. Plant Physiol. doi: 10.1104/pp.17.01490. Open Access

The current GARNet PI Jim Murray and past GARNet coordinator Ruth Bastow are authors in this international consortium that suggests future directions for the global Arabidopsis community. This consortium is led by Joanna Friesner and concludes that it is critical that the next generation of plant scientists receive appropriate training in bioinformatics and quantitative biology so as to take advantage of the remarkable array of datasets that are now available to Arabidopsis researchers.


Berry S, Rosa S, Howard M, Bühler M, Dean C (2017) Disruption of an RNA-binding hinge region abolishes LHP1-mediated epigenetic repression Genes Dev. doi: 10.1101/gad.305227.117 Open Access

Caroline Dean (John Innes Centre) leads this study that investigates the role of the polycomb associated protein LIKE HETEROCHROMATIN PROTEIN 1 (LHP1) in the regulation of the repressive histone mark H3K27me3. They demonstrate that the intrinsically disordered hinge region of LHP1 is responsible for RNA-binding and that disruption of this region prevents the formation of sub-nuclei foci, provides a potential link to wider epigenetic regulation.


Lee YJ, Hiwatashi Y, Hotta T, Xie T, Doonan JH, Liu B (2017) The Mitotic Function of Augmin Is Dependent on Its Microtubule-Associated Protein Subunit EDE1 in Arabidopsis thaliana. Current Biol. doi: 10.1016/j.cub.2017.11.030

Open Access

John Doonan and colleague at Aberystwyth University are co-authors on this study regarding the role of the Microtubule-Associated Protein Subunit EDE1, which is a member of the Augmin complex, during mitosis. EDE1 specifically localised with the augmin complex during spindle formation, a role that cannot be replaced by the homologous protein AUG8. This work reveals that specificity of the augmin complex can be determined by interaction with subunits that only contribute to complex function during particular phases of the cell cycle.


Zhang X, Jayaweera D, Peters JL, Szecsi J, Bendahmane M, Roberts JA, González-Carranza ZH (2017) The Arabidopsis thaliana F-box gene HAWAIIAN SKIRT is a new player in the microRNA pathway. PLoS One. doi: 10.1371/journal.pone.0189788 Open Access

Zinnia Gonzalez-Carranza (Nottingham) is the corresponding author on this study that follows on from work published earlier in 2017 regarding the role of the HAWAIIAN SKIRT gene is plant development. In this latest work they identify mutations in the previously characterized Exportin-5 HASTY gene as suppressors of the hws mutant phenotype. Further investigation shows that HWS genetically interacts with other genes involved in miRNA pathway indicates that HWS somehow interacts with biogenesis, accumulation or function of these small RNAs.


Townsend AJ1, Ware MA1, Ruban AV (2017) Dynamic interplay between photodamage and photoprotection in photosystem II. Plant Cell Environ doi: 10.1111/pce.13107

In this paper Alexander Ruban (QMUL) is the corresponding author on work that expands his groups contribution to the understanding of the role non-photochemical quenching (NPQ) plays during photoinhibition. In this work they compare the activity of NPQ versus endogenous photosystemI repair mechanisms in the maintenance of photosynthetic activity during photoinhibitory conditions. Overall they conclude that NPQ is a more important mechanism for photoprotection under short periods of illumination.


Hansen LL, Imrie L, Le Bihan T, van den Burg HA, van Ooijen G (2017) Sumoylation of the Plant Clock Transcription Factor CCA1 Suppresses DNA Binding. J Biol Rhythms doi: 10.1177/0748730417737695 Open Access

This paper from the Van Ooijen lab accompanies one that was featured in last weeks ARR and extends their finding that sumoylation plays an important role in control of the circadian clock. In this paper they show that the CCA1 clock protein is sumoylated and that perturbing this modification alters the binding of CCA1 to a target promotor, even though it’s localization or stability were unaffected. Using an in vitro system they show that sumoylation is a direct determinant of CCA1 binding to its target promotor suggesting that this PTM fine tunes the activity of this key circadian control element.


Belfield EJ, Ding ZJ, Jamieson FJC, Visscher AM, Zheng SJ, Mithani A, Harberd NP (2017) DNA mismatch repair preferentially protects genes from mutation. Genome Res. doi: 10.1101/gr.219303.116

Past GARNet Advisory board member Nick Harberd (Oxford) leads this multi-generational study on the effect of DNA mismatch repair (MMR) on maintenance of an entire genome. They perform whole genome sequencing across five generations of Arabidopsis plants with a mutation in the MMR pathway and show that particular types of nucleotide error are more prevelant amongst the total 9000 mutations that accumulate. Interestingly they show that single nucleotide variants are more likely to accumulate in genic regions, indicating that protein coding areas of the genome are preferentially protected from damage.


Bagchi R, Melnyk CW, Christ G, Winkler M,, Kirchsteiner K, Salehin M, Mergner J, Niemeyer M, Schwechheimer C, Calderón Villalobos LIA, Estelle M (2017) The Arabidopsis ALF4 protein is a regulator of SCF E3 ligases. EMBO J. doi: 10.15252/embj.201797159

During his time as a research fellow at the Sainsbury lab in Cambridge. Charles Melynk contributed to this research that is a throwback to the early day of Arabidopsis mutant analysis. The alf4 was first described as a possible auxin mutant in 1995 and this work brings this study full circle by characterising the ALF4 protein as a novel regulator of SCF complexes, which are known to be involved in auxin and GA signaling. ALF4 specifically functions by interacting with the SCF-core component RBX1. Future work will determine whether this effect is specific to SCFs involved in hormone signaling or whether it is a more general effect.

Arabidopsis Research Roundup: December 8th.

This weeks Research Roundup begins with two papers from the University of Edinburgh on very different topics of Arabidopsis research. Firstly Alistair McCormick and Sofirtios Tsaftaris introduce a new low-cost phenotyping platform whilst Gerben Ooijen’s group has analysed the role of SUMOylation in the control of the circadian clock. The next three papers each involve wide UK collaborations and either look at plant nutrient composition (Nottingham, Dundee, York), the role of N-end rule pathway in the control of seed storage mobilisation (Rothamsted, Nottingham, Oxford, Birmingham, Cambridge) or the development of a new tool for the study of phloem sieve elements (Leeds, Rothamsted, Cambridge, Newcastle). The penultimate paper from Daniel Zilbermann (JIC) highlights the global mechanisms of methyltransferase function in Arabidopsis and mice whilst the final paper from Alexandre Ruban (QMUL) and co-authors continues his groups work to unpick the specifics of NPQ.


Dobrescu A, Scorza LCT, Tsaftaris SA, McCormick AJ (2017) A “Do-It-Yourself” phenotyping system: measuring growth and morphology throughout the diel cycle in rosette shaped plants. Plant Methods. doi: 10.1186/s13007-017-0247-6

Open Access

University of Edinburgh colleagues Alistair McCormick and Sofirtios Tsaftaris lead this work that presents a low cost phenotyping system for the analysis of the growth rate and phenotypic characteristics of Arabidopsis thaliana rosettes. The software that they have developed allows the accurate segmentation of multiple rosettes within a single image and overall offers a straightforward solution for automated phenotyping across a range of growth environments.


Hansen LL, van den Burg HA, van Ooijen G (2017) Sumoylation Contributes to Timekeeping and Temperature Compensation of the Plant Circadian Clock. J Biol Rhythms. doi: 10.1177/0748730417737633

Gerben van Ooijen (University of Edinburgh) is the corresponding author of this work that has identified SUMOylation as a novel mechanism of regulating circadian clock genes in Arabidopsis. Plants with defects in sumoylation have altered circadian periods that exhibit incorrect temperature compensation. Overall these results indicate that sumoylation importantly buffers clock function in response to changing temperatures.


Alcock TD, Havlickova L, He Z, Bancroft I, White PJ, Broadley MR, Graham NS (2017) Identification of Candidate Genes for Calcium and Magnesium Accumulation in Brassica napus L. by Association Genetics. Front Plant Sci. doi: 10.3389/fpls.2017.01968

Open Access

Neil Graham and Martin Broadley (University of Nottingham) are the corresponding authors of this study that has taken advantage of the Brassica napus Associative Transcriptomes RIPR diversity panel developed by Ian Bancroft’s lab in York. Novel loci involved with an altered response to calcium and magnesium were identified in B.napus before mineral composition was analysed in Arabidopsis mutants defective in orthologous genes. The analysed plants exhibited alteration in mineral composition, meaning that the associated Brassica loci might be targets for future breeding strategies aimed at improving plant nutrient compositions.


Zhang H, Gannon L, Hassall KL, Deery MJ, Gibbs DJ, Holdsworth MJ, van der Hoorn RAL, Lilley KS, Theodoulou FL (2017) N-terminomics reveals control of Arabidopsis seed storage proteins and proteases by the Arg/N-end rule pathway. New Phytol. doi: 10.1111/nph.14909

Freddie Theodoulou (Rothamsted Research) is the corresponding author of this research that involved a collaboration with colleagues in Cambridge, Birmingham, Nottingham and Oxford. They have performed a proteomic analysis on etiolated seedlings to identify those proteins designated for degradation by the N-end rule pathway. They analysed prt6 mutant plants that lack the function of the E3 ligase PROTEOLYSIS6 (PRT6) and discovered that N-terminal peptides from 45 protein groups were upregulated in this mutant, corresponding to the equivalent downregulation of several known N-end rule proteases. Overall the authors show that PRT6 plays an important role in the regulation of seed storage mobilisation in young seedlings and is therefore a possible future target to manipulate the plant responses to adverse environmental conditions. Dr Kirsty Hassall, a statistician at Rothamsted, is an author on this paper and in the latest edition of the GARNish newsletter explains how she interacts with plant scientists during her work.


Torode TA, O’Neill RE, Marcus SE, Cornuault V, Pose-Albacete S, Lauder RP, Kracun SK, Gro Rydahl M, Andersen MCF, Willats WGT, Braybrook SA, Townsend BJ, Clausen MH, Knox JP (2017) Branched pectic galactan in phloem-sieve-element cell walls: implications for cell mechanics. Plant Physiol. doi: 10.1104/pp.17.01568 Open Access

Paul Knox (University of Leeds) is the corresponding author of this study that includes contributions from researchers at SLCU, Newcastle and Rothamsted. This work is based around the development of a monoclonal antibody, LM26 that is able to recognize a β-1,6-galactosyl substitution of β-1,4-galactan. LM26 has allowed the identification of this unusual branched galactan that is specific to phloem elements and the authors hope that it can be a useful tool in future studies on the biology of phloem elements


Lyons DB, Zilberman D (2017) DDM1 and Lsh remodelers allow methylation of DNA wrapped in nucleosomes. Elife. doi: 10.7554/eLife.30674 Open Access

Daniel Zilberman has recently moved to the John Innes Centre and is the lead author of this work that was conducted when he was working in US. This research is a cross-kingdom analysis showing that nucleosome-free DNA is the preferred target for methyltransferases in both Arabidopsis and mice, and that nucleosomes appear to be a barrier to the function of these enzymes. Furthermore they demonstrate that linker-specific methylation that is usually absent in Arabidopsis can be introduced by removal of histone H1. This shows that flowering plants still possess this ability despite its loss, during the evolution of H1, over a billion years ago.


Tutkus M, Chmeliov J, Rutkauskas D, Ruban AV, Valkunas L (2017) Influence of the Carotenoid Composition on the Conformational Dynamics of Photosynthetic Light-Harvesting Complexes. J Phys Chem Lett. doi: 10.1021/acs.jpclett.7b02634

Alexandre Ruban (QMUL) is a co-author on this study that investigates the role that carotenoid composition plays in the control of Non-photochemical quenching (NPQ), a mechanism that protects the photosynthetic apparatus from light-damage. Arabidopsis mutants with differing carotenoid compositions were analysed for the dynamics of the conformation switches that occur during NPQ. Interestingly they show that LHCII has robust function  that is resistant to different carotenoid concentrations.

Devin O’Connor talks to GARNet

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Published on: November 30, 2017

Devin O’Connor discusses auxin, PINs and protein instrinic qualities during our discussion of his recent eLife paper entitled ‘Cross-species functional diversity within the PIN auxin efflux protein family’.
https://elifesciences.org/articles/31804
https://www.slcu.cam.ac.uk/research/oconnor-group

Arabidopsis Research Roundup: Nov 24th

The week’s UK Arabidopsis research roundup includes seven papers from groups who work on a range of topics.

Firstly Antony Dodd (Bristol) investigates the role of sugar signaling during hypocotyl elongation and provides an audio description of this groups work. Secondly Mike Holdsworth (Nottingham) leads a paper that demonstrates the importance of the N-rule pathway in the response to abiotic stresses. Thirdly are a set of papers that have developed models on three different topics. Mike Blatt’s group at Glasgow University has a cross-scale model that is applied to stomatal opening whilst Stan Maree and Veronica Griensien (JIC) use modeling to predict how the topology of pavement cells is determined. Finally Arabidopsis is used as an example that fits a model that investigates how critical mutation rate (CMR) changes with population size. In the sixth paper Lorraine Williams and colleagues (University of Southampton) investigate the function of a rice transport protein involved in manganese tolerance by expressing it in Arabidopsis. The final paper from Jerzy Paszkowski (SLCU) outlines a novel screening strategy for retrotransposons and the identification of an ecotype specific element.


Simon NM, Kusakina J, Fernández-López Á, Chembath A, Belbin FE, Dodd AN (2017) The energy-signalling hub SnRK1 is important for sucrose-induced hypocotyl elongation. Plant Physiol. doi: 10.1104/pp.17.01395

Open Access

This UK-wide collaboration is led by Anthony Dodd at the University of Bristol and has looked at the factors that control hypocotyl elongation in response to sugar signalling. This response is integrated through the sugar-signalling hub, SnRK1 and is regulated by trehalose-6-phosphate (Tre6P). They also integrate hormone signalling and the influence of diurnal rhythms into the control of this process, importantly showing that the ubiquitous sugar regulator hexokinase is not involved in this process.

Antony kindly provides an audio description of this research that can be found on YouTube or on the GARNet iTunes channel. Please subscribe!


Vicente J, Mendiondo GM, Movahedi M, Peirats-Llobet M, Juan YT, Shen YY, Dambire C, Smart K, Rodriguez PL, Charng YY, Gray JE, Holdsworth MJ (2017) The Cys-Arg/N-End Rule Pathway Is a General Sensor of Abiotic Stress in Flowering Plants. Current Biology doi: 10.1016/j.cub.2017.09.006

Open Access

Mike Holdsworth (University of Nottingham) is the corresponding author of this collaboration with colleagues from Sheffield, Spain and Taiwan that investigates how the N-rule degradation pathway acts a sensor of general abiotic stress in both Arabidopsis and Barley. These responses are integrated through degradation of the group VII Ethylene Response Factor transcription factors (ERFVIIs) family via direct and indirect pathways. In addition they link ERFVII activity with chromatin-remodeling ATPase BRAHMA providing evidence for a single mechanism that links the responses to a number of environmental signals.


Wang Y, Hills A, Vialet-Chabrand SR, Papanatsiou M, Griffiths H, Rogers S, Lawson T, Lew V, Blatt MR (2017) Unexpected Connections between Humidity and Ion Transport Discovered using a Model to Bridge Guard Cell-to-Leaf Scales. Plant Cell. doi: 10.1105/tpc.17.00694

Open Access

Mike Blatt (University of Glasgow) leads this collaboration with researchers at the Universities of Cambridge and Essex. They have developed the OnGuard2 quantitative systems platform that integrates numerous parameters that control guard cell dynamics across many scales including at molecular, cellular, tissue and canopy levels. They experimentally demonstrate that OnGuard2 faithfully reproduces the kinetics of real stomatal movement and therefore that this modeling is able to bridge the micro-macro divide.


Carter R, Sánchez-Corrales YE, Hartley M, Grieneisen VA, Marée AFM (2017) Pavement cells and the topology puzzle. Development. doi: 10.1242/dev.157073

Stan Maree and Veronica Griensien (John Innes Centre) lead this study that has looked at the patterning of 50000 Arabidopsis pavement cells to understand the topological signatures that exist in this population. They have developed a heuristic cellular division rule to produce a model that can reproduce their observations by predicting how these cells divide. They confirmed their model by tracking 800 mitotic events, allowing them to conclude that distinct topology is not a direct consequence of the jigsaw-like shape of the cells, but rather owes itself to life-history-driven process, with limited impact from cell surface mechanics.


Aston E, Channon A, Belavkin RV, Gifford DR, Krašovec R, Knight CG (2017) Critical Mutation Rate has an Exponential Dependence on Population Size for Eukaryotic-length Genomes with Crossover. Sci Rep. doi: 10.1038/s41598-017-14628-x

Open Access

In this study a team of computational biologists from Keele, Middlesex and Manchester have used Arabidopsis as an exemplar to understand how critical mutation rate (CMR) provides insights into the shift between survival-of-the-fittest and survival of individuals with greater mutational robustness. They have produced a simulation for these parameters that predicts outcomes for a range of biological organisms, showing that CMR decreases with reduced population size. They suggest that the model can be used to understand the conservation strategies exhibited in populations that are approaching extinction.


Farthing EC, Menguer PK, Fett JP, Williams LE (2017) OsMTP11 is localised at the Golgi and contributes to Mn tolerance. Sci Rep. doi: 10.1038/s41598-017-15324-6
Lorraine Williams (University of Southampton) and her colleagues have identified a transporter protein from rice, OsMTP11 that is involved in mangenase tolerance. They show that heterologous expression of this protein is able to rescue the manganese sensitive phenotype of Arabidopsis mtp11-3 knockouts. They show that OsMTP11 localises to the Golgi and have also conducted site directed mutagenesis to identify key residues that are important for the function of this protein.


Griffiths J, Catoni M, Iwasaki M, Paszkowski J (2017) Sequence-independent identification of active LTR retrotransposons in Arabidopsis. Mol Plant. doi: 10.1016/j.molp.2017.10.012

Open Access

Jerzy Paszkowski (SLCU) leads this single-figure short manuscript that has characterised the population of retrotransposons in Arabidopsis. They develop a novel cost-effective screening strategy that allows them to identify sequences found on extrachromosomal DNA (ecDNA), which includes a retroelement found in Lansberg erecta but not in the reference genome ecotype Col-0.

Anthony Dodd talks to GARNet

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Published on: November 24, 2017

Anthony Dodd (Universit of Bristol) talks to GARNet about a recent paper published in Plant Physiology entitled ‘The energy-signalling hub SnRK1 is important for sucrose-induced hypocotyl elongation‘.

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