GARNet Research Roundup: November 22nd 2019

This bumper edition of the GARNet Research Roundup begins with three papers that have a focus on the circadian clock. First is from Cambridge and looks at a novel role for TTG1 in control of the clock. The second paper also includes co-authors from Cambridge and looks at the clock Evening Complex. The final clock paper includes co-authors from York and looks at the new roles for EARLY FLOWERING 3 and GIGANTEA.

The next four papers include researchers from the John Innes Centre. Yiling Ding’s lab lead an exciting study into the role of RNA G-quadruplex to define liquid-liquid phase separations. Next David Seung and Alison Baker look at production of amylose starch across Arabidopsis accessions. The third JIC paper is from the Charpentier lab and looks at nuclear calcium signaling in the root. Finally Lars Ostergaard is a co-author on a paper that identifies a novel biostimulant that controls podshatter in Brassica.

The eighth paper is from Glasgow and describes the bioengineering of plants to express a novel antibiotic bacteriocin.

Next are three papers introduce exciting new research tools. 1. Weibei Yang in the Meyerowitz lab introduces a method for co-labeling of RNAs and protein 2. Researchers in Nottingham introduce RootNav2.0 for the automated measurement of root archtiectures 3. The Haydon Lab has developed a GAL4-GFP luciferase system for tissue-specific gene expression analysis.

Two Photosynthesis-based papers come next with firstly an analysis on the link between metabolism and the light response curve (from Manchester) and secondly a look at the role of aquaporins in control of CO2 conductance (Cambridge and Lancaster).

The fourteenth paper is from Durham and characterises an important protein regulator of the autophagy-dependent degradation pathway whilst the fifteenth is from Cambridge and uses cryo-SEM to analyse cell wall structures.

The penultimate paper is from Birmingham and looks at the role of redox signaling in aphid fecundity and the final paper includes co-authors from RHUL and looks at the interaction between the E2FB and RETINOBLASTOMA-RELATED proteins.


Airoldi CA, Hearn TJ, Brockington SF, Webb AAR, Glover BJ (2019) TTG1 proteins regulate circadian activity as well as epidermal cell fate and pigmentation. Nat Plants. doi: 10.1038/s41477-019-0544-3

This study from the University of Cambridge is led by Chiara Airoldi and introduces a new role for the TRANSPARENT TESTA GLABRA 1 (TTG1) WD-repeat (WDR) subfamily in the regulation of the circadian clock. TTG1 regulates epidermal cell differentiation and pigment production, while LIGHT-REGULATED WD1 and LIGHT-REGULATED WD2A are known to regulate the clock. The triple lwd1 lwd2 ttg1 mutant has no detectable circadian rhythym. This suggests that members of this protein family have undergone subfunctionalization to diverge from their core functions. This paper is of interest to those who research evolution of protein function as well as the to those interested in the control of the circadian clock.

https://www.nature.com/articles/s41477-019-0544-3

Tong M, Lee K, Ezer D, Cortijo S, Jung J, Charoensawan V, Box MS, Jaeger K, Takahashi N, Mas P, Wigge PA, Seo PJ (2019) The Evening Complex establishes repressive chromatin domains via H2A.Z deposition. Plant Physiol. doi: 10.1104/pp.19.00881

This collaboration between the UK and South Korea is led by Meixuezi Tong and investigates how the Evening Complex (EC) component of the circadian clock interacts with chromatin to control gene expression at dusk. This occurs through direct interaction with the SWI2/SNF2-RELATED complex and together they bind to the core clock genes PRR7 and PRR9, causing the deposition of H2A.Z at these loci subsequent to causing their repression at dusk.


Anwer MU, Davis A, Davis SJ, Quint M (2019) Photoperiod sensing of the circadian clock is controlled by EARLY FLOWERING 3 and GIGANTEA. Plant J. doi: 10.1111/tpj.14604

Amanda Davies and Seth Davies from the University of York are co-authors on this German-led study with Muhammad Anwer as both first and corresponding author. They look at the role of important circadian regulators ELF3 and GIGANTEA through generation of previously unanalysed elf3gi double mutants. In these plants the circadian oscillator fails to synchronize to light-dark cycles even under diurnal conditions, demonstrating that these genes act together to convey photoperiod sensing to the central oscillator.


Zhang Y, Yang M, Duncan S, Yang X, Abdelhamid MAS, Huang L, Zhang H, Benfey PN, Waller ZAE, Ding Y (2019) G-quadruplex structures trigger RNA phase separation. Nucleic Acids Res. doi: 10.1093/nar/gkz978
Open Access

Yueying Zhang is the first author of this study conducted in the lab of Yiliang Ding at the John Innes Centre, in collaboration with the Benfey lab in the USA. They reveal an exciting mode of regulating RNA activity through the formation of RNA G-quadruplex (GQ) complexes. They use the SHORTROOT mRNA as the model for this study, showing that GQ-mediated complex formation can bring liquid-liquid phase separation. This study is of fundamental importance as it provides the first evidence that RNA can adopt structural motifs to trigger and/or maintain the specificity of RNA-driven phase separation.

https://academic.oup.com/nar/advance-article/doi/10.1093/nar/gkz978/5624975?guestAccessKey=d3913912-fdbb-4f35-aa71-625442722842

Seung D, Echevarría-Poza A, Steuernagel B, Smith AM (2019) Natural polymorphisms in Arabidopsis result in wide variation or loss of the amylose component of starch. Plant Physiol. doi: 10.1104/pp.19.01062
Open Access

David Seung at the John Innes Centre the first and corresponding author of this study that used data from the Arabidopsis 1135 Genome project to investigate the prevelance of amylose production. Plants with amylose-free starch have no detrimental phenotypes so the function of this glucose-polymer, that accounts for up to 30% of all natural starch, is unknown. They looked at the polymorphisms within the GRANULE-BOUND STARCH SYNTHASE (GBSS) enzyme, identifying natural accessions that have no GBSS activity yet are viable within their natural environments. This study is a prelude to future research that will discover the adaptive significance of amylose.


Leitão N, Dangeville P, Carter R, Charpentier M (2019) Nuclear calcium signatures are associated with root development. Nat Commun. doi: 10.1038/s41467-019-12845-8
Open Access

Nuno Leitao is first author on this research from the Charpentier lab at the John Innes Centre. They looked at the role of nuclear Ca2+ signalling on primary root meristem development and auxin homeostasis through activity of the nuclear membrane localised ion channel DOES NOT MAKE INFECTIONS 1 (DMI1). This study discovers a previously unappreciated role for intracellular Ca2+ signalling during plant development.


Łangowski Ł, Goñi O, Quille P, Stephenson P, Carmody N, Feeney E, Barton D, Østergaard L, O’Connell S (2019 A plant biostimulant from the seaweed Ascophyllum nodosum (Sealicit) reduces podshatter and yield loss in oilseed rape through modulation of IND expression. Sci Rep. doi: 10.1038/s41598-019-52958-0
Open Access

Lars Ostergaard is a co-author on this Irish-study led by Lukasz Łangowski that investigates the factors that control pod shatter in oil seed rape. They show that the seaweed Ascophyllum nodosum-based biostimulant (Sealicit) is able to reduce podshatter by effecting the expression of the major regulator of pod shattering, INDEHISCENT. This has implications for the use of this compound by farmers wanting to reduce the amount of seed loss due to premature pod shatter.


Rooney WM, Grinter RW, Correia A, Parkhill J, Walker DC, Milner JJ (2019) Engineering bacteriocin-mediated resistance against the plant pathogen Pseudomonas syringae. Plant Biotechnol J. doi: 10.1111/pbi.13294
Open Access

William Rooney at the University of Glasgow is lead author on this study that attempts to combat Pseudomonas syringae infections through expression of a novel protein antibiotic bacteriocin, putidacin. They show that transgenic expression of this bacterial protein provides effective protection against Pseudomonas. This proof of concept opens the possibility for more widespread use of bacteriocins as an effective plant protection strategy.

https://onlinelibrary.wiley.com/doi/epdf/10.1111/pbi.13294

Yang W, Schuster C, Prunet N, Dong Q, Landrein B, Wightman R, Meyerowitz EM (2019) Visualization of Protein Coding, Long Non-coding and Nuclear RNAs by FISH in Sections of Shoot Apical Meristems and Developing Flowers. Plant Physiol. doi: 10.1104/pp.19.00980
This extended methods paper is led by Weibing Yang at the Sainsbury lab in Cambridge. They have adapted RNA fluorescence in situ hybridization (rnaFISH) to explore RNA localization in the shoot apical meristem of Arabidopsis. They are able to label mRNA as well as long ncRNAs and have developed double labeling to assay two separate RNAs in the same cell and to assess nucleo-cytoplasmic separation of RNA species. Finally they link rnaFISH with fluorescence immunocytochemistry for the simultaneous localization of a single genes mRNA and protein.

https://www.frontiersin.org/articles/10.3389/fpls.2019.01398/full

Yasrab R, Atkinson JA, Wells DM, French AP, Pridmore TP, Pound MP (2019) RootNav 2.0: Deep learning for automatic navigation of complex plant root architectures. Gigascience. doi: 10.1093/gigascience/giz123
Open Access

Robail Yasrab is lead author on this work from the University of Nottingham that introduces the RootNav2.0 software tool. This was developed by modern deep-learning approaches and allows the fully automated measurement of vertically growth root systems. RootNav2.0 was favourably compared with its semi-automated predecessor RootNav1.0 and can be used for measurement of root architectures from a range of different plant species.


Román Á, Golz JF, Webb AA, Graham IA, Haydon MJ (2019) Combining GAL4 GFP enhancer trap with split luciferase to measure spatiotemporal promoter activity in Arabidopsis. Plant J. doi: 10.1111/tpj.14603

This technical advance is led by Angela Roman, was in the Haydon lab during its time at the University of York. They have used the GAL4-GFP enhancer trap system, to develop a tissue-specific split luciferase assay for non-invasive detection of spatiotemporal gene expression in Arabidopsis. In this example they use the study to measure dynamics of circadian gene expression but is clearly applicable to answer many other experimental questions.


Herrmann HA, Schwartz JM, Johnson GN (2019) From empirical to theoretical models of light response curves – linking photosynthetic and metabolic acclimation. Photosynth Res. doi: 10.1007/s11120-019-00681-2
Open Access

Helena Herrmann is lead author on this work fro the University of Manchester. In this study they developed and then empirically tested a series of simple kinetic models that explains the metabolic changes that are required to alter light response curves (LRCs) across a range of temperatures. This allowed them to show how changes in NADPH and CO2 utilization respond to environmental changes. This provides useful information as to how a plant adapts its metabolic response to light depending on the growth temperature.

Helena explaining her research

Kromdijk J, Głowacka K, Long SP (2019) Photosynthetic efficiency and mesophyll conductance are unaffected in Arabidopsis thaliana aquaporin knock-out lines. J Exp Bot. doi: 10.1093/jxb/erz442

Open Access
Wanne Kromdijk leads this US-led research that includes contributions from the Universities of Cambridge and Lancaster. They looked at the potential role of membrane-bound aquaporins in the control of diffusion conductance for CO2 transfer from substomatal cavity to chloroplast stroma (gm). They tested three aquaporin mutants across a range of light and CO2 concentrations and surprisingly found that they appear to play no significant contribution to the control of gm. The reporting of this type of ‘negative’ result will prevent unnecessary replication of experiments and help to streamline the research process.


Wang P, Pleskot R, Zang J, Winkler J, Wang J, Yperman K, Zhang T, Wang K, Gong J, Guan Y, Richardson C, Duckney P, Vandorpe M, Mylle E, Fiserova J, Van Damme D, Hussey PJ (2019) Plant AtEH/Pan1 proteins drive autophagosome formation at ER-PM contact sites with actin and endocytic machinery. Nat Commun. doi: 10.1038/s41467-019-12782-6
Open Access

Pengwei Wang is first author in this research led from Durham University that incudes Chinese and Belgian collaborators. They show that the AtEH/Pan1 protein is involved with actin cytoskeleton regulated autophagy and recruits multiple other components to autophagosomes during this process. In addition they show vesicle bound-AtEH/Pan1 interact with VAP27-1 at the ER-PM. This demonstrates that AtEH/Pan1 is a key component of the autophagy-dependent degradation pathway.


Lyczakowski JJ, Bourdon M, Terrett OM, Helariutta Y, Wightman R, Dupree P (2019) Structural Imaging of Native Cryo-Preserved Secondary Cell Walls Reveals the Presence of Macrofibrils and Their Formation Requires Normal Cellulose, Lignin and Xylan Biosynthesis. Front Plant Sci. doi: 10.3389/fpls.2019.01398
Open Access

Jan Lyczakowski from the Dupree lab at the University of Cambridge is first author on this study that has adapted low temperature scanning electron microscopy (cryo-SEM) to visualize the cell walls of both angiosperm and gymnosperms. They have used Arabidopsis mutants to reveal that cell wall macrofibrils at composed of cellulose, xylan, and lignin. They demonstrate that cryo-SEM is a useful tool for native nanoscale cell wall architectures.


Rasool B, Karpinska B, Pascual J, Kangasjärvi S, Foyer CH (2019) Catalase, glutathione and protein phosphatase 2A-dependent organellar redox signalling regulate aphid fecundity under moderate and high irradiance. Plant Cell Environ. doi: 10.1111/pce.13669
Brwa Rasool is first author on this collaboration between the Universities of Birmingham and Helsinki that looks at how aphids respond to redox changes in Arabidopsis thaliana grown under different light conditions. They also identified defence-related transcription factors differentially upregulated by aphid predation in different light conditions. Overall they show aphid fecundity is in part determined by the plants cellular redox signaling.


Őszi E, Papdi C, Mohammed B, Pettkó-Szandtner A, Vaskó-Leviczky T, Molnár E, Ampudia CG, Khan S, Lopez-Juez E, Horváth B, Bögre L, Magyar Z (2019) E2FB interacts with RETINOBLASTOMA RELATED and regulates cell proliferation during leaf development. Plant Physiol. doi: 10.1104/pp.19.00212
Erika Oszi is first author of this Hungarian-led research that includes co-authors from Royal Holloway University of London. This research looks at the interaction between the transcription factors E2FB and RETINOBLASTOMA-RELATED (RBR) and how this contributes to cell proliferation during organ development in Arabidopsis leaves. The relationship between these proteins changes throughout the stages of leaf development and is critical to determine final leaf cell number.

http://www.plantphysiol.org/content/early/2019/11/06/pp.19.00212.long

GARNet Research Roundup: July 5th 2019

This edition of the GARNet research roundup begins with a study from the University Leicester that investigates the rate of selection of genes expressed in Arabidopsis pollen.

The second and third papers focus on the function of members of the AP2 family of transcription factors. Sarah McKim’s lab in Dundee characterizes the role of APETALA2 during barley stem elongation whilst the other paper investigates the function of the Arabidopsis PUCHI gene and includes co-authors from the University of Nottingham.

The fourth paper is from Lars Ostergaard’s lab at the John Innes Centre and demonstrates the benefit of using models to understand developmental processes in crop plants. The next paper from the University of Glasgow investigates the plant response to low fluence rates of UV-B light.

The penultimate paper features authors from Oxford Brookes University and characterizes a novel LINC-KASH protein in maize whilst the final paper is from the University of Cambridge and investigates the novel function of two members of DUF579 family in methylation of glucuronic acid residues.


Harrison MC, Mallon EB, Twell D, Hammond RL (2019) Deleterious mutation accumulation in Arabidopsis thaliana pollen genes: a role for a recent relaxation of selection. Genome Biol Evol. doi: 10.1093/gbe/evz127

Open Access

This research from Hammond and Twell lab’s at the University of Leicester uses Arabidopsis to investigate the hypothesis that pollen genes evolve faster than sporophytic genes. This study is challenging to perform in Arabidopsis as for the past million years the plant has been self-compatible, which causes reduction in pollen competition, increased homozygosity and a dilution of masking in diploid expressed, sporophytic genes. This study has two main findings: firstly prior to becoming self-compatible pollen genes evolved faster than sporophytic genes. Secondly, since becoming self-compatible selection has relaxed causing higher polymorphism levels and a higher build-up of deleterious mutations.


Patil V, McDermott HI, McAllister T, Cummins M, Silva JC, Mollison E, Meikle R, Morris J, Hedley PE, Waugh R, Dockter C, Hansson M, McKim SM (2019) APETALA2 control of barley internode elongation. Development. doi: 10.1242/dev.170373

Open Access

Vrushali Patil leads his study from the lab of current GARNet committee member Sarah McKim at the James Hutton Institute in Dundee. They show that the APETALA2 (AP2) transcription factor is necessary for stem elongation in Barley. In addition they demonstrate that AP2 expression is controlled by the activity of the microRNA mi172 as well as jasmonate signaling.

https://dev.biologists.org/content/146/11/dev170373.long

Trinh DC, Lavenus J, Goh T, Boutté Y, Drogue Q, Vaissayre V, Tellier F, Lucas M, Voß U, Gantet P, Faure JD, Dussert S, Fukaki H, Bennett MJ, Laplaze L, Guyomarc’h S (2019) PUCHI regulates very long chain fatty acid biosynthesis during lateral root and callus formation. Proc Natl Acad Sci U S A. doi: 10.1073/pnas.1906300116

Julien Lavenus, Ute Voß and Malcolm Bennett from University of Nottingham are co-authors on this French-led study that investigates the mechanism by which the AP2 family transcription factor PUCHI controls lateral root development. By performing a transcriptional analysis of developing lateral root cells they show that genes involved in very long chain fatty acid (VLCFA) biosynthesis enzymes are induced in a PUCHI dependent manner. Concomitantly they show puchi-1 mutant roots have reduced VLCFA content when compared with wildtype roots. They conclude that PUCHI regulates VLCFA biosynthesis as part of a pathway controlling cell proliferation during lateral root formation.


Stephenson P, Stacey N, Brüser M, Pullen N, Ilyas M, O’Neill C, Wells R, Østergaard L (2019) The power of model-to-crop translation illustrated by reducing seed loss from pod shatter in oilseed rape. Plant Reprod. doi: 10.1007/s00497-019-00374-9

Open Access

Pauline Stephenson and Lars Østergaard at the John Innes Centre lead this study in which they demonstrate that lessons learnt from understanding the genes involved in fruit ripening in Arabidopsis lead to an ability to adjust the pod-opening process in oilseed rape. They have combined two mutant alleles, first characterized in Arabidopsis, to develop OSR plants that have significantly increased yield. In addition they present a new software tool for the analysis of pod shatter data in other crops plants.


O’Hara A, Headland LR, Díaz-Ramos LA, Morales LO, Strid Å, Jenkins GI (2019) Regulation of Arabidopsis gene expression by low fluence rate UV-B independently of UVR8 and stress signaling. Photochem Photobiol Sci. doi: 10.1039/c9pp00151d

Open Access

This UK-Swedish collaboration is led by Andrew O’Hara from the Jenkins lab in the University of Glasgow. They continue the lab focus on the UV-B receptor UVR8, in this case performing a transcriptomic analysis of wildtype and uvr8 mutants grown under low UV-B fluence rates. They analyse one differentially expressed gene in more detail, the transcription factor ARABIDOPSIS NAC DOMAIN CONTAINING PROTEIN 13 (ANAC13), which was induced by UV-B but by the activity of any other photoreceptor.


Gumber HK, McKenna JF, Tolmie AF, Jalovec AM, Kartick AC, Graumann K, Bass HW (2019) MLKS2 is an ARM domain and F-actin-associated KASH protein that functions in stomatal complex development and meiotic chromosome segregation Nucleus. doi: 10.1080/19491034.2019.1629795

Open Access

Hardeep Gumber is first author on this US-led study that includes Joe KcKenna, Andrea Tolmie and Katja Graumann from Oxford Brookes as co-authors. They characterise the Maize LINC KASH AtSINE-like2 protein, MLKS2, whose targeting to the nuclear periphery requires its N-terminal armadillo repeats. Mutant mlks2 plants have pleiotropic plant phenotypes and on a nuclear level show defects in chromosome segregation and positioning. These findings support a model in which cytoplasmic actin is linked to chromatin through the LINC-KASH nuclear envelope network.

https://www.tandfonline.com/doi/full/10.1080/19491034.2019.1629795

Temple H, Mortimer JC, Tryfona T, Yu X, Lopez-Hernandez F, Sorieul M, Anders N, Dupree P (2019) Two members of the DUF579 family are responsible for arabinogalactan methylation in Arabidopsis. Plant Direct. doi: 10.1002/pld3.117

Open Access

Henry Temple is first author on this work from the University of Cambridge that characterizes two members of the DUF579 family (AGM1 and AGM2). These proteins are required for 4-O-methylation of glucuronic acid within highly glycosylated arabinogalactan proteins (AGPs).


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GARNet Research Roundup: April 11th 2019

This edition of the GARNet Research Roundup is led by two papers from John Christie’s lab at the University of Glasgow. First is a study that looks at the function of the NPH3 protein during phototropism whilst the second paper is a collaboration with Mike Blatt’s group and has used an synthetic biology approach to increase plant biomass by altering stomatal conductance.

Third is a paper from the University Dundee and James Hutton Institute that looks at the extent of alternative splicing of long non-coding RNAs in response to cold stress.

The fourth paper is from Royal Holloway and defines the role of a MAP kinase module during meristem development. The fifth paper is led by Charles Spillane in Galway and includes Mary O’Connell at the University of Nottingham as a co-author and investigates the selective pressures that are applied to parentally imprinted genes.

The penultimate paper is from Aberystwyth and uses microCT imaging to determine grain parameters in wheat and barley whilst the final paper is from Queens Mary University of London looks at nonphotochemical quenching in Berteroa incana.


Sullivan S, Kharshiing E, Laird J, Sakai T, Christie J (2019) De-etiolation Enhances Phototropism by Modulating NON-PHOTOTROPIC HYPOCOTYL 3 Phosphorylation Status. Plant Physiol. doi: 10.1104/pp.19.00206

Open Access

Stuart Sullivan is first author on this work from John Christie’s lab at the University of Glasgow in which they investigate the functional significance of dephosphorylation of the NON-PHOTOTROPIC HYPOCOTYL 3 (NPH3) protein that occurs following activation of Phototropin receptor kinases. They show that plant greening (de-etiolation) enhances phototropic responses that are coincident with reduced NPH3 dephosphorylation and increased plasma membrane retention of the protein. They further investigate other genetic and environmental factors that impact NPH3 dephosphorylation, which allows young seedlings to maximise their establishment under changing light conditions.


Papanatsiou M, Petersen J, Henderson L, Wang Y, Christie JM, Blatt MR (2019) Optogenetic manipulation of stomatal kinetics improves carbon assimilation, water use, and growth. Science. doi: 10.1126/science.aaw0046

Maria Papanatsiou is lead author on this work from the University of Glasgow that occured in the labs of Mike Blatt and John Christie. They aimed to address a phenomonen that occurs during changing environmental conditions in which stomatal dynamics lag behind biochemical photosynthetic changes. This prevents plants from maximising their outputs due to inefficiencies in gas and water exchange. In this work they express a synthetic blue light-gated K+ channel BLINK1 in guard cells. This introduced a K+ conductance to these cells resulting in accelerated stomatal opening under light exposure and closing after irradiation. Ultimately they show that this significantly increases biomass without incurring a water use cost. This approach has clear potential for improving plant productivity under changing environmental conditions.

https://science.sciencemag.org/content/363/6434/1456.long

Calixto CPG, Tzioutziou NA, James AB, Hornyik C, Guo W, Zhang R, Nimmo HG, Brown JWS (2019) Cold-Dependent Expression and Alternative Splicing of Arabidopsis Long Non-coding RNAs. Front Plant Sci. doi: 10.3389/fpls.2019.00235

Open Access

Cristiane Calixto and John Brown from the University of Dundee and the James Hutton Institute lead this study into alternative splicing of lncRNAs in response to cold. This is a follow-up to their large scale scale study on the extent of alternative splicing in Arabidopsis.  The authors identified 135 lncRNA genes with cold-dependent differential expression (DE) and/or differential alternative splicing (DAS), some of which were highly sensitive to small temperature changes. This system identified a set of lncRNAs that could be targets for future research aimed at understanding how plants respond to cold and freezing stresses.


Dóczi R, Hatzimasoura E, Farahi Bilooei S, Ahmad Z, Ditengou FA, López-Juez E, Palme K, Bögre L (2019) The MKK7-MPK6 MAP Kinase Module Is a Regulator of Meristem Quiescence or Active Growth in Arabidopsis. Front Plant Sci. doi: 10.3389/fpls.2019.00202

Open Access

Robert Doczi is the first author on this UK, Hungarian and German collaboration that is led from Royal Holloway University of London. They use genetic approaches to show that the MKK7-MPK6 MAP kinase module is a suppressor of meristem activity. They use mkk7 and mpk6 mutants as well as overexpression lines to demonstrate that perturbation of the MAPK signaling pathway alters both shoot and root meristem development and plays important roles in the control of plant developmental plasticity.


Tuteja R, McKeown PC, Ryan P, Morgan CC, Donoghue MTA, Downing T, O’Connell MJ, Spillane C (2019) Paternally expressed imprinted genes under positive Darwinian selection in Arabidopsis thaliana. Mol Biol Evol. doi: 10.1093/molbev/msz063

Open Access

Reetu Tuteja from the National University of Ireland at Galway is first author on this paper that includes Mary O’Connell from the University of Nottingham. The authors used Arabidopsis to look at 140 endosperm-expressed genes that are regulated by genomic imprinting and found that they were evolving more rapidly than expected. This investigation was extended across 34 other plant species and they found that paternally, but not maternally imprinted genes were under positive selection, indicating that imprinted genes of different parental origin were subject to different selective pressures. This data supports a model wherein positive selection effects paternally-expressed genes that are under continued conflict with maternal sporophyte tissues.


Hughes N, Oliveira HR, Fradgley N, Corke FMK, Cockram J, Doonan JH, Nibau C (2019) μCT trait analysis reveals morphometric differences between domesticated temperate small grain cereals and their wild relatives. Plant J doi: 10.1111/tpj.14312

Open Access

Nathan Hughes and Candida Nibau at the Aberystwyth University lead this work that uses microCT imaging alongside novel image analysis techniques and mathematical modeling to assess grain size and shape across accessions of wheat and barley. They find that grain depth is a major driver of shape change and that it is also an excellent predictor of ploidy levels. In addition they have developed a model that enables the prediction of the origin of a grain sample from measurements of its length, width and depth.


Wilson S, Ruban AV (2019) Enhanced NPQ affects long-term acclimation in the spring ephemeral Berteroa incana. Biochim Biophys Acta Bioenerg. doi: 10.1016/j.bbabio.2019.03.005

This study is led by Sam Wilson and Alexander Ruban at QMUL and investigates nonphotochemical quenching in the Arabidopsis-relative Berteroa incana. They show that light tolerance and ability to recover from light stress is greatly enhanced in Berteroa compared to Arabidopsis. This is due to faster synthesis of zeaxanthin and a larger xanthophyll cycle (XC) pool available for deepoxidation. This result gives B.incana a greater capacity for protective NPQ allowing enhanced light-harvesting capability when acclimated to a range of light conditions. The authors suggest this short-term protection prevents the need for the metabolic toll of making long-term acclimations.

GARNet Research Roundup: March 21st 2019

This edition of the GARNet research roundup begins with a study from the John Innes Centre that investigates the role of auxin in the control of fruit development in Capsella.

Auxin is also a central focus of the next paper that is from SLCU, in which the authors characterise the role of different types of auxin transport during shoot development. The third paper, also from Cambridge, identifies a new function for members of the DUF579 enzyme family. The final paper from Cambridge reports on an outstanding citizen science project that looks at how different temperature and light conditions influence the growth of spring onions.

The next paper is from the University of Glasgow and investigates the role of the SNARE protein complex during vesicle transport in Arabidopsis.

The final two papers include authors from the University of Nottingham. Firstly Anthony Bishopp leads research that defines determinants of vascular patterning across plant species. Finally Don Grierson is a co-author on work that has identified novel signaling components involved in the response to hypoxia in Persimmon and Arabidopsis.


Dong Y, Jantzen F, Stacey N, Łangowski Ł, Moubayidin L, Šimura J, Ljung K, Østergaard L (2019) Regulatory Diversification of INDEHISCENT in the Capsella Genus Directs Variation in Fruit Morphology. Curr Biol. doi: 10.1016/j.cub.2019.01.057

Open Access

This research from Lars Ostergaard’s lab in the John Innes Centre is led by Yang Dong. The work is primarily conducted in Capsella and investigates the role of the INDEHISCENT (IND) protein in this plant, which has fruits that are morphologically distinct from those in Arabidopsis. Expression of CrIND controls fruit shape by influencing auxin biosynthesis leading to auxin accumulation in specific maxima that are localised to the fruit valves.

doi: 10.1016/j.cub.2019.01.057

van Rongen M, Bennett T, Ticchiarelli F, Leyser O (2019) Connective auxin transport contributes to strigolactone-mediated shoot branching control independent of the transcription factor BRC1. PLoS Genet. doi: 10.1371/journal.pgen.1008023

Open Access

Martin Van Rongen is the lead author on this research performed under the supervision of Ottoline Leyser at the Sainsbury Lab, Cambridge University. They investigate the hormonal signals that underpin the remarkable plasticity of shoot patterning, focusing on a genetic analysis of connective auxin transport (CAT), which moves the hormone across the stem (in contrast to up-down polar transport). Using multiple pin mutant plants, they show CAT is important in the regulation of strigolactone-mediated shoot branching. However shoot branching controlled by the BRANCHED1 transcription factor is reliant on the ABCB19 auxin export protein and is not significantly influenced by the activity of PIN proteins. Martin van Rongen discusses this paper on the GARNet YouTube channel.


Temple, H, Mortimer, JC, Tryfona, T, et al (2019) Two members of the DUF579 family are responsible for arabinogalactan methylation in Arabidopsis. Plant Direct. https://doi.org/10.1002/pld

Open Access

Henry Temple works with Paul Dupree at the University of Cambridge and leads this study that identifies a novel activity of two DUF579 enzymes in the methylation of glucuronic acid within highly glycosylated arabinogalactan proteins (AGPs). This differs from all other previously characterized DUF579 members that have been previously shown to methylate glucuronic acid within the cell wall component xylan.


Brestovitsky, A, Ezer, D (2019) A mass participatory experiment provides a rich temporal profile of temperature response in spring onions. Plant Direct. 2019; 3: 1– 11. https://doi.org/10.1002/pld3.126

Open Access

This citizen science project led by Anna Brestovitsky and Daphne Ezer was performed in collaboration with the BBC Terrific Scientific program. In this study primary school students from across the UK recorded the growth of spring onions over a two-week period, which was then cross-referenced with detailed hourly meteorological data. This allowed the authors to discern the effect of minute temperature and light changes on plant growth and perhaps more importantly demonstrated that even the youngest researchers, when involved a well-designed citizen science project, can yield very useful data.


Zhang B, Karnik RA, Alvim JC, Donald NA, Blatt MR (2019) Dual Sites for SEC11 on the SNARE SYP121 Implicate a Binding Exchange during Secretory Traffic. Plant Physiol. doi: 10.1104/pp.18.01315

Open Access

Ben Zhang and Rucha Karnik are first authors on this paper that continues Mike Blatt‘s lab’s study of SNARE proteins, which are involved in vesicle trafficking. This study defines a new amino acid motif within SNARE SYP121 that is needed for the binding of the SEC11 protein but is not involved in binding plasma membrane K+ channels. This motif is essential for assembly of the entire SNARE complex yet does not influence the interaction of SYP121 with the uptake of K+ ions.


Mellor N, Vaughan-Hirsch J, Kümpers BMC, Help-Rinta-Rahko H, Miyashima S, Mähönen AP, Campilho A, King JR, Bishopp A (2019) A core mechanism for specifying root vascular patterning can replicate the anatomical variation seen in diverse plant species. Development. doi: 10.1242/dev.172411

Open Access

Nathan Mellor is first author on this work led by the lab of Anthony Bishopp at the University of Nottingham. The primary accomplishment of this work is in the development of a mathematical model that is able to predict the role of auxin in the specification of vascular patterning during embryonic development. This model has been tested through experimental interrogation of both transgenic Arabidopsis plants and in a range of other species with different vascular development patterns. Importantly they show that a heterologous auxin input might not be as critical in vascular development when compared to growth patterns that arise from spatial constraints. The authors show that this model has broad relevance to define early vascular patterning across plant species.


Zhu QG, Gong Z, Huang J, Grierson D, Chen KS, Yin XR (2019) High-CO2/hypoxia-responsive transcription factors DkERF24 and DkWRKY1 interact and activate DkPDC2 promoter. Plant Physiol. doi: 10.1104/pp.18.01552

Open Access

Don Greirson is a co-author on this Chinese-led study that identifies a set of transcription factors from Persimmon ((Diospyros kaki). These TFs are involved in responses to high CO2 and the authors show that their Arabidopsis orthologs play a similar role. The authors introduce a new response module that may be important during this key environmental response.

GARNet Research Roundup: November 1st 2018

This week’s GARNet research roundup again features papers on a variety of topics. First is work from the University of Leeds that investigates the physical properties of callose:cellulose hydrogels and the implication for cell wall formation. Second is work from the University of York that assesses the role of the HSP90.2 protein in control of the circadian clock. The third paper features GARNet committee member Sarah McKim and looks at the genetic control of petal number whilst the next paper from the Universities of Warwick and Glasgow includes a proteomic analysis of different types of secretory vesicles.

The next two papers look at different aspects of hormone signaling. Firstly Alistair Hetherington from the University of Bristol is a co-author on a study that looks at the role of the BIG protein whilst Simon Turner’s lab in Manchester investigates the role of ABA in xylem fibre formation.

The penultimate paper includes Lindsey Turnbull from the University of Oxford and looks at the stability of epialleles across 5 generations of selection. Finally is a paper that includes researchers from TSL in Norwich who have contributed to a phosphoproteomic screen to identify phosphorylated amino acids that influence the defence response.


Abou-Saleh R, Hernandez-Gomez M, Amsbury S, Paniagua C, Bourdon M, Miyashima S, Helariutta Y, Fuller M, Budtova T, Connell SD, Ries ME, Benitez-Alfonso Y (2018) Interactions between callose and cellulose revealed through the analysis of biopolymer mixtures. Nature Communications DOI: 10.1038/s41467-018-06820-y

https://www.nature.com/articles/s41467-018-06820-y

Open Access
Radwa Abou-Saleh is lead author on this work from Yoselin Benitez-Alfonso’s lab at the University of Leeds. (1,3)-β-glucans such as callose play an important role in plant development yet their physical properties are largely unknown. This study analyses a set of callose:cellulose hydrogel mixtures as a proxy for different cell wall conditions. They show that callose:cellulose hydrogels are more elastic than those composed of only cellulose, providing evidence that the interactions between cellulose and callose are important for the structural features of cell walls.


Davis AM, Ronald J, Ma Z, Wilkinson AJ, Philippou K, Shindo T, Queitsch C, Davis SJ (2018) HSP90 Contributes To Entrainment of the Arabidopsis Circadian Clock via the Morning Loop. Genetics. doi: 10.1534/genetics.118.301586

http://www.genetics.org/content/early/2018/10/18/genetics.118.301586.long

Open Access
Amanda Davies is the first author on this study from Seth Davies’ lab at the University of York in which they assess the role of the molecular chaperone HSP90.2 on function of the circadian clock. The show hsp90.2-3 mutant plants have a lengthened circadian period with a specific defect in the morning. This data allows the authors to better understand the pathway through which HSP90.2 functions to entrain the circadian clock.


Monniaux M, Pieper B, McKim SM, Routier-Kierzkowska AL, Kierzkowski D, Smith RS, Hay A. The role of APETALA1 in petal number robustness. Elife. doi: 10.7554/eLife.39399

https://elifesciences.org/articles/39399

Open Access
GARNet committee member Sarah McKim is a co-author on this paper, that is led by Marie Monniaux, which includes research from her time at the University of Oxford. This work from the Hay lab in Cologne compares petal number in Arabidopsis thaliana, in which the number is invariant, and Cardamine hirsute, in which it varies. They show that petal number robustness can be attributed to the activity of the APETALA1 (AP1) floral regulator and that AP1 masks the activity of several genes in Arabidopsis but not in Cardamine.


Waghmare S, Lileikyte E, Karnik RA, Goodman JK, Blatt MR, Jones AME (2018) SNAREs SYNTAXIN OF PLANTS 121 (SYP121) and SYP122 mediate the secretion of distinct cargo subsets . Plant Physiol. doi: 10.1104/pp.18.00832

http://www.plantphysiol.org/content/early/2018/10/23/pp.18.00832.long

Open Access

This collaboration between the Universities of Glasgow and Warwick is led by Sakharam Waghmare, who works with Mike Blatt in Glasgow. This study uses proteomic approaches to characterise the secretory cargos within vesicles decorated with either of the SNARE proteins SYNTAXIN OF PLANTS 121 (SYP121) or SYP122. Genetic analysis suggests that SYP121 and SYP122 have redundant functions but this new research is able to identify cargo proteins that are either contained within both types of vesicle or that are specific to one or the other.


Zhang RX, Ge S, He J, Li S, Hao Y, Du H, Liu Z, Cheng R, Feng YQ, Xiong L, Li C, Hetherington AM, Liang YK (2018) BIG regulates stomatal immunity and jasmonate production in Arabidopsis. New Phytol. doi: 10.1111/nph.15568

Alistair Hetherington is a co-author on this China-based study led by Ruo‐Xi Zhang from Wuhan. This work adds to some recent interest in the BIG protein; in this study showing that it is involved in the interaction between JA and ethylene signaling during stress responses. In a complex set of interactions they show that the BIG protein differently alters opposing arms of the JA signaling pathway providing additional evidence that this protein is a key regulator of plant hormone signaling, albeit by a set of as yet unknown mechanisms.


Campbell L, Etchells JP, Cooper M, Kumar M, Turner SR. An essential role for Abscisic acid in the regulation of xylem fibre differentiation. Development. doi: 10.1242/dev.161992

This work from Simon Turner’s lab at the University of Manchester is led by Liam Campbell and identifies a novel role for ABA in the formation of xylem fibres during secondary thickening of the Arabidopsis hypocotyl. The action of ABA doesn’t alter the xylem:phloem ratio but rather the activity focuses on the formation of fibres within the already defined xylem tissue.


Schmid MW, Heichinger C, Coman Schmid D, Guthörl D, Gagliardini V, Bruggmann R, Aluri S, Aquino C, Schmid B, Turnbull LA, Grossniklaus U (2018) Contribution of epigenetic variation to adaptation in Arabidopsis. Nat Commun. doi: 10.1038/s41467-018-06932-5

https://www.nature.com/articles/s41467-018-06932-5

Open Access
Lindsey Turnbull (University of Oxford) is a co-author on this paper from Ueli Grossniklaus’ group in Zurich. Marc Schmid is lead author of the study that investigates the inheritance of Arabidopsis epialleles over 5 generations during conditions of simulated selection. The authors show that variations in methylation state are subject to selection and do indeed contribute to adaptive responses


Kadota Y, Liebrand TWH, Goto Y, Sklenar J, Derbyshire P, Menke FLH, Torres MA, Molina A, Zipfel C, Coaker G, Shirasu K (2018) Quantitative phosphoproteomic analysis reveals common regulatory mechanisms between effector- and PAMP-triggered immunity in plants. New Phytol. doi: 10.1111/nph.15523

Members of Cyril Zipfel’s group at The Sainsbury lab in Norwich are co-authors on this paper led by Yasuhiro Kadota from the RIKEN in Yokohama. They use a phosphoproteomic screen to identify a set of newly identified phosphorylation sites on membrane-associated proteins involved in effector-triggered immunity (ETI). Some of these phosphosites overlap with those known to be important for pathogen-associated molecular pattern (PAMP)-triggered immunity (PTI), indicating a convergence of signaling control of both these pathways to certain key residues.

GARNet Research Roundup: July 27th

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Published on: July 26, 2018

This GARNet research roundup includes papers that feature a number of different research areas. Firstly is work from Glasgow that investigates the photoactivation of the UVR8 light receptor. Second is work from the University of Cambridge that links the activity of the BIG protein to the circadian oscillator. The next paper has co-authors from Cambridge and looks at promotor sequences needed for expression in bundle sheath cells. The fourth paper from the University of Leeds documents an important role for peroxisomes in the drought response whilst the final manuscript includes co-authors from the University of Birmingham and looks at the role of the ASYNAPTIC4 protein during meiosis.


http://pubs.rsc.org/en/Content/ArticleLanding/2018/PP/C8PP00138C#!divAbstract

Díaz-Ramos LA, O’Hara A, Kanagarajan S, Farkas D, Strid Å, Jenkins GI. Difference in the action spectra for UVR8 monomerisation and HY5 transcript accumulation in Arabidopsis (2018) Photochem Photobiol Sci. doi: 10.1039/c8pp00138c

Open Access

Aranzazu Díaz-Ramos and Andrew O’Hara are co-first authors on this research from the University of Glasgow that investigates the activation of photomorphogenic responses by the UVR8 photoreceptor. They show that two distinct UVR8 responses, either the monomerisation of UVR homodimers or accumulation of HY5 responsive transcripts, occurs at different wavelengths.


Hearn TJ, Marti MC, Abdul-Awal SM, Wimalasekera R, Stanton CR, Haydon MJ, Theodoulou FL, Hannah MA, Webb AA (2018) BIG regulates dynamic adjustment of circadian period in Arabidopsis thaliana. Plant Physiology pp.00571.2018. doi: 10.1104/pp.18.00571

Open Access

Timothy Hearn works with Alex Webb at the University of Cambridge and in this paper characterises how the multi-functional BIG protein impacts the circadian clock. This gene was isolated in a forward genetics screen to identify signaling components that alter the response to nicotinamide, which acts as a brake on the circadian oscillator. This finding allows the authors to better understand how altering the circadian oscillator can affect appropriate phasing during different environmental conditions.


Kirschner S, Woodfield H, Prusko K, Koczor M, Gowik U, Hibberd JM, Westhoff P. Expression of SULTR2;2 in the Arabidopsis bundle sheath and vein cells is mediated by a positive regulator. J Exp Bot. 2018 Jul 19. doi: 10.1093/jxb/ery263

Open Access

Sandra Kirschner is first author on this German-led study that includes Helen Woodfield (now Cardiff University) and Julian Hibberd (University of Cambridge). They are interested in the mechanisms that restrict gene expression to bundle sheath cells in C3 plants with a longer view of understanding the biology of these cells in C4 plants. They analyse the vascular-restricted SULTR2;2 promotor and identified a short region that is necessary for its expression pattern. Importantly they show that this sequence is evolutionarily conserved across Brassicaceae and a distantly related C4 plant.

https://academic.oup.com/jxb/advance-article/doi/10.1093/jxb/ery263/5056055


Ebeed HT, Stevenson S, Cuming AC, Baker A. Conserved and differential transcriptional responses of peroxisome associated pathways to drought, dehydration and ABA. J Exp Bot. 2018 Jul 19. doi: 10.1093/jxb/ery266

Open Access

Heba Ebeed is the lead author of this work conducted in Alison Baker’s lab at the University of Leeds. They take a comparative genomics approach to investigate the expression of peroxisome-localised genes in a moss (physcomitrella), monocot (wheat) and a dicot (arabidopsis). They show that members of three gene families are upregulated in each of these organisms following drought stress, demonstrating the importance of peroxisomes in this environmental response throughout plant evolution.


Chambon A, West A, Vezon D, Horlow C, De Muyt A, Chelysheva L, Ronceret A, Darbyshire AR, Osman K, Heckmann S, Franklin FCH, Grelon M (2018) Identification of ASYNAPTIC4, a component of the meiotic chromosome axis. Plant Physiol. pii: pp.01725.2017. doi: 10.1104/pp.17.01725

Chris Franklin and Alice Darbyshire from the University of Birmingham are co-authors on this French-led study that looks into the role of the ASYNAPTIC4 (ASY4) protein in the control of synapsis formation during meiosis. Plants without ASY4 activity have defective chromosomal axis formation and cannot undergo synapsis. Although the initiation of recombination is unaffected in asy4 mutants, later processes are altered, demonstrating the key role for ASY4 during meiosis

GARNet Research Roundup: June 4th

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


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

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

Open Access

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

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


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

Open Access

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


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

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


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

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

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


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

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

GARNet Research Roundup: May 17th

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


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

Open Access

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

Eirini discusses this paper on the GARNet YouTube channel.


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

https://elifesciences.org/articles/31700

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


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

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

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


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

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

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


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

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


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

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

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