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.

Arabidopsis Research Roundup: October 5th

After a brief hiatus the UK Arabidopsis Research Roundup returns with eight papers that focus on different aspects of Arabidopsis cell biology.

Firstly GARNet PI Jim Murray leads a study that performs a genome-wide analysis of sub-nucleosomal particles whilst Phil Wigge’s lab at SLCU conducts a more focused study on G-box regulatory sequences.

Thirdly Veronica Grieneisen (JIC) and co-workers have modelled the process of boron transport in the root, revealing exciting insights into how traffic jams might form.

Fourthly is a large scale biology paper led by Miriam Gifford (University of Warwick) that looks at the temporal and spatial expression patterns that control lateral root development.

Next Alexander Ruban (QMUL) investigates how low-light acclimated plants respond to high light.

The sixth and seventh studies are led by Alison Baker (Leeds) or Bill Davies (Lancaster) and look at phosphate or hormone signaling respectively.

Finally Gareth Jenkins (University of Glasgow) compares the UV-B signaling module in lower plants with that in Arabidopsis.

Pass DA, Sornay E, Marchbank A, Crawford MR, Paszkiewicz K, Kent NA, Murray JAH (2017) Genome-wide chromatin mapping with size resolution reveals a dynamic sub-nucleosomal landscape in Arabidopsis. PLoS Genet. doi: 10.1371/journal.pgen.1006988

Open Access

GARNet PI Jim Murray is the corresponding author on this study that performs a whole-genome scan of sub-nucleosomal particles (subNSPs) that have been identified using differential micrococcal nuclease (MNase) digestion. They link the position of subNSPs with RNAseq data taken from plants grown in different light conditions. They show that this new technique is able to discriminate regulatory regions that have been obscured by previous experimental procedures and therefore represents a very useful experimental method.

Ezer D, Shepherd SJ, Brestovitsky A, Dickinson P, Cortijo S, Charoensawan V, Box MS, Biswas S, Jaeger K, Wigge PA (2017) The G-box transcriptional regulatory code in Arabidopsis. Plant Physiol. 10.1104/pp.17.01086

Open Access

Phil Wigge (SLCU) is the corresponding author of this study that investigates the sequence elements that are linked to the conserved G-box regulatory motifs. They identify a set of bZIP and bHLH transcription factors that predict the expression of genes downstream of perfect G-boxes. In addition they have developed a website that provide visualisations of the G-box regulatory network (

Sotta N, Duncan S, Tanaka M, Takafumi S, Marée AF, Fujiwara T, Grieneisen VA (2017) Rapid transporter regulation prevents substrate flow traffic jams in boron transport. Elife. doi: 10.7554/eLife.27038

Open Access

Veronica Grieneisen (JIC) is the lead author on this detailed analysis of the regulatory circuits that are established during boron uptake in Arabidopsis roots. They used mathematical modelling to show that during boron uptake, swift regulation of transport activity is needed to prevent toxic accumulation of the metal. This system has analogy to the way in which traffic jams of nutrient flow might form and has relevance for regulatory systems outside of plant science.

Walker L, Boddington C, Jenkins D, Wang Y, Grønlund JT, Hulsmans J, Kumar S, Patel D, Moore JD, Carter A, Samavedam S, Bomono G, Hersh DS, Coruzzi GM, Burroughs NJ, Gifford ML (2017) Root architecture shaping by the environment is orchestrated by dynamic gene expression in space and time. Plant Cell. doi: 10.1105/tpc.16.00961

Open Access

Miriam Gifford (University of Warwick) leads this broad consortium that has taken a systems biology approach to better define the environmental factors that control dynamic root architecture. They track transcriptional responses during lateral root development in remarkable detail, looking at individual transcripts. They confirm the idea that the activity of a gene is not simply a function of its amino acid sequence but rather the temporal and spatial regulation of its expression.

Tian Y, Sacharz J, Ware MA, Zhang H, Ruban AV (2017) Effects of periodic photoinhibitory light exposure on physiology and productivity of Arabidopsis plants grown under low light. J Exp Bot. doi: 10.1093/jxb/erx213. Open Access

Alexander Ruban (QMUL) is the corresponding author on this collaboration with Chinese colleagues that examined the effect of high-light stress on low-light acclimated Arabidopsis plants. Initially these plants showed significant photo-inhibition but that they recovered rapidly and after 2 weeks of treatment there was no change in photosynthetic yield. In addition high light acclimated plants showed accelerated reproductive phase change that coincided with higher seed yield.

Qi W, Manfield IW, Muench SP, Baker A (2017) AtSPX1 affects the AtPHR1 -DNA binding equilibrium by binding monomeric AtPHR1 in solution. Biochem J. doi: 10.1042/BCJ20170522 Open Access

Alison Baker (University of Leeds) leads this research that focusses on the binding of the Phosphate Starvation Response 1 (PHR1) transcription factor to regulatory P1BS DNA sequences. They show a tandem P1BS sequence is bound more strongly than a single P1BS site. Ultimately they demonstrate tight regulation of phosphate signaling both by the concentration of phosphate as well as the activity of the interacting SPX protein.

Li X, Chen L, Forde BG, Davies WJ (2017) The Biphasic Root Growth Response to Abscisic Acid in Arabidopsis Involves Interaction with Ethylene and Auxin Signalling Pathways. Front Plant Sci. doi: 10.3389/fpls.2017.01493 Open Access

Bill Davies and Brian Forde (Lancaster University) lead this work that investigates the effect on ethylene and auxin on the biphasic response to ABA during root elongation. They used a range of hormone signalling mutants to show that the response to high ABA is via both ethylene and auzin signalling. In contrast the response to low ABA does not require ethylene signalling.

Soriano G, Cloix C, Heilmann M, Núñez-Olivera E, Martínez-Abaigar J, Jenkins GI (2017) Evolutionary conservation of structure and function of the UVR8 photoreceptor from the liverwort Marchantia polymorpha and the moss Physcomitrella patens. New Phytol. doi: 10.1111/nph.14767

Gareth Jenkins (University of Glasgow) is the corresponding author of this work that looks at the role of the UVR8 UV-B receptor in lower plants. They expressed the versions of UVR8 from a moss or a liverwort in Arabidopsis and showed that although there appears to be differences in the regulation of this protein, the mechanism of UV-B signaling is evolutionarily conserved

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: October 12th

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Published on: October 11, 2015

The Arabidopsis Research Roundup is ‘defense-focused’ this week. We present three papers that highlight different aspects of plant immunity, two of which result from UK-US-China collaborations. Firstly a team from the Sainsbury Lab, Norwich looks at two molecular mechanisms that control stomatal closure. There are then two studies that involve University of Exeter researchers that investigate either the role of plant hormones in the response to bacterial pathogens or the role that the physical barrier of the cell wall plays in the prevention of infection. Next a group of JIC researchers present a Large Scale Biology investigation of microtubule interacting proteins. Finally a study from QMUL looks at the interaction between NPQ and photoinhibition in controlling the activity of Photosystem II.

Gou M, Zhang Z, Zhang N, Huang Q, Monaghan J, Yang H, Shi Z, Zipfel C, Hua J (2015) Opposing effects on two phases of defense responses from concerted actions of HSC70 and BON1 in Arabidopsis. Plant Physiol.

GARNet Advisory Board Member Cyril Zipfel is the UK lead on this US-China-UK collaboration that looks at two aspects of the plant immune response that are regulated by the same proteins, albeit in an antagonistic way. The heat shock protein HSC70 and the calcium binding protein BON1 both are involved in stomatal closure, the formers effect mediated by the SNC1 protein and the latter (BON1) via the activitation of SGT1 that in turn inhibits HSC70. These new functions demonstrate opposing roles for HSC80 and BON1 in the immune response and further highlight the complexity of the signaling pathways that ultimately feed into the gross phenotypic change of stomatal closure.

de Torres Zabala M, Zhai B, Jayaraman S, Eleftheriadou G, Winsbury R, Yang R, Truman W, Tang S, Smirnoff N, Grant M (2015) Novel JAZ co-operativity and unexpected JA dynamics underpin Arabidopsis defence responses to Pseudomonas syringae infection New Phytol.

This is another UK-USA-China collaboration led by Murray Grant at the University of Exeter, in which the role of the plant hormones is assessed in the response to bacterial pathogens. The defence response is mediated by both the hormones salicylic acid (SA) and jasmonic acid (JA) which antagnise many of each others activity. Pathogens have been shown to produce a JA-mimic cornatine (COR) in order to stall SA-mediated effects. In this study the authors use a systems-biology based approach that involved targeted hormone profiling, high-temporal-resolution micro-array analysis, reverse genetics and mRNA-seq to introduce a complex network of regulation that involves JAZ proteins, which are repressors of the JA signal. In short they show that JAZ5 and JAZ10 specifically co-operate to inhibit pathogen growth by restricting COR cytotoxicity by novel mechanisms, which do not involve previously well-defined signaling proteins.

Marcos R, Izquierdo Y, Vellosillo T, Kulasekaran S, Cascón T, Hamberg M, Castresana C (2015) 9-Lipoxygenase-derived oxylipins activate brassinosteroid signaling to promote cell wall-based defense and limit pathogen infection Plant Physiol.

This work was performed in Madrid under the supervision of Carmen Castresana but includes the work of Satish Kulasekaran who is now at the Exeter. The focus of the work is the oxylipins, which are oxygenated lipid derivatives that regulate plant development and immunity. Using a variety of noxy mutants (non-responding to oxylipins) they show that the effect of the oxylipins is mediated via changes in the cell wall and this is signalled via the Brassinosteriod response pathway. Suspectibility to bacterial and fungal infection was enhanced in noxy mutants but plants were resistance when BR signalling was switched on. Therefore this manuscript introduces an important interaction between the oxylipins and BR signalling and helps to clarify their role in modulating plant defense.

Derbyshire P, Ménard D, Green P, Saalbach G, Buschmann H, Lloyd CW, Pesquet E (2015) Proteomic Analysis of Microtubule Interacting Proteins over the Course of Xylem Tracheary Element Formation in Arabidopsis Plant Cell.

The experiments in this Large Scale Biology paper were performed in the lab of Clive Lloyd (John Innes Centre) which included the work of Eduoard Pesquet, who now has his own lab in Sweden. They looked the microtubule patterning that defines the nature of tracheary element (TEs) thickening in plant vascular tissues. They used Arabidopsis cell suspension culture to isolate microtubule interacting proteins present during TE differentiation. One protein of interest was CELLULOSE SYNTHASE-INTERACTING PROTEIN1, associated with primary wall synthesis, which was enriched during secondary cell wall formation of TEs. The authors knocked-down the expression of some of their identified proteins and indeed showed that they were important for this differentiation. A take-home message is that the proteins that interact with microtubules and link them to different metabolic compartments do indeed specifically vary during TE differentiation, regulating different aspects of cell wall patterning.

Giovagnetti V, Ruban AV (2015) Discerning the effects of photoinhibition and photoprotection on the rate of oxygen evolution in Arabidopsis leaves J Photochem Photobiol B.

Arabidopsis Research Roundup Regular Alexandre Ruban (QMUL) again looks at the mechanisms that lessen the amount of photoinhibition (when photosystem II is damaged by being exposed to too much light). An opposing response is Non-photochemical quenching (NPQ) of chlorophyll a fluorescence which serves to protect PSII from high light conditions. In this study they confirm that a recently devised procedure that aims to discern between the effect of NPQ and photoinhibition works well as a measurement for the efficiency of PSII activity.

Arabidopsis Research Roundup: August 12th

The UK Arabidopsis Research Roundup this week includes a couple of EVO-DEVO-type studies that compare processes within different organisms (Physcomitrella and Cardamine) to those occurring in Arabidopsis. These include the evolution of both hormone signaling and leaf development. Elsewhere a cell-biological focused study looks at the factors that control formation of plasmodesmata whilst another manuscript investigates the details of a plants mechanism to avoid photoinhibition.

Yasumura Y1, Pierik R2, Kelly S3, Sakuta M4, Voesenek LA5, Harberd NP (2015) An Ancestral Role for Constitutive Triple Response 1 (CTR1) Proteins in Both Ethylene and Abscisic Acid Signaling Plant Physiology

GARNet Advisory Board Member Nick Harberd leads this study that investigates the evolution of the CONSTITUTIVE TRIPLE RESPONSE 1 (CTR1) protein, which has known to be involved in ethylene signalling for two decades. CTR1 is compared between mosses, lycophytes and angiosperms, showing that PpCTR1 from moss Physcomitrella patens has the same function and the Arabidopsis equivalent, indicating that this signaling pathway predates the land plant lineage. However PpCTR1 is also involved in ABA signaling, which is not the case with AtCTR1 and may be explained by the presence of an AtCTR1 homolog in angiosperms. The authors state that this work provides new insights into the molecular events that contributed to the adaptive evolution of regulatory mechanisms across plant species

Kirsten Knox, Pengwei Wang, Verena Kriechbaumer, Jens Tilsner, Lorenzo Frigerio, Imogen Sparkes, Chris Hawes, Karl Oparka (2015) Putting the Squeeze on Plasmodesmata: A Role for Reticulons in Primary Plasmodesmata Formation Plant Physiology

This study is led by Karl Oparka (Edinburgh) and Chris Hawes (Oxford Brookes) as well as including PIs from Exeter (Sparkes), Warwick (<a href="http://www2.warwick cialis professional 20” onclick=”_gaq.push([‘_trackEvent’, ‘outbound-article’, ‘’, ‘Frigerio’]);” target=”_blank”>Frigerio) and St Andrews (Tilsner). The manuscript investigates formation of plasmodesmata (PD), which are known to form from endoplasmic reticulum (ER) via an intermediant termed the desmotubule. Members of the Reticulon (RTNLB) family of ER-tubulating proteins are found in the PD proteome are are associated with developing PD following cell division. The authors use super-resolution imaging to show that RTNLB6 colocalises with desmotubules. The mobility of these RTNLB proteins was show, using FRAP, to vary dependent on their positioning within a developing cell plate. Mutant studies show that RTNLB proteins act as important regulators of the formation of PDs and the authors discuss the wider potential roles of these proteins in this process.

Ware MA, Giovagnetti V, Belgio E, Ruban AV (2015) PsbS protein modulates non-photochemical chlorophyll fluorescence quenching in membranes depleted of photosystems J Photochem Photobiol B

Alexander Ruban (QMUL) continues a fine run of recent publications with this study that investigates plants that express increased levels of the photosynthetic PsbS protein, in the context of a subsequent increase in levels of non-photochemical fluorescence quenching (NPQ). In these PsbS overexpressors, there is increased amplitude of the irreversible NPQ component, qI, which likely results from aggregation of the LHCII antenna complex. Use of freeze-fracture electron microscopy show that quenched thylakoids have 3x more aggregated LHCII particles compared to those that are dark-adapted. Overall, these results demonstrate the importance of this LHCII aggregation in the NPQ mechanism whilst showing that structure of the PSII supercomplex plays no role in formation in process of quenching.

Cartolano M, Pieper B, Lempe J, Tattersall A, Huijser P, Tresch A, Darrah PR, Hay A, Tsiantis M (2015) Heterochrony underpins natural variation in Cardamine hirsuta leaf form Proc Natl Acad Sci U S A. 2015 Aug 4.

The study is a continuation of many years of work led by Miltos Tsiantis (who maintains links with Oxford University), aimed at increasing the understanding of how different morphological patterns develop. They compare leaf patterning in Arabidopsis (which has a simple leaf) and in the related plant, Cardamine (that has a complex leaf). They have identified a novel QTL from Cardamine that shows that age-dependent progression of leaf form underlies variation in this trait within species. Interestingly the QTL mapped to a cis-acting region controlling expression of the floral regulator FLC. Genotypes expressing low levels of FLC show early flowering and accelerated changes in leaf form, including faster leaflet production. These findings link reproductive timing with leaf development and the authors speculate that this may help to optimize resource allocation to the next generation.

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