GARNet Research Roundup: February 7th 2020

This latest edition of the GARNet Research Roundup begins with two studies that look at different aspects of lateral root formation and include members of Malcolm Bennett’s lab in Nottingham. The first investigates a critical role for hydropatterning in the control of lateral root initiation whilst the second looks at how cell death in overlying tissue layers plays an active role in the control of lateral root emergence.

The third paper is from the John Innes Centre and investigates the mechanism through which a small number of noncoding SNPs can alter chromatin dynamics at the FLC locus. The fourth paper is from Glasgow and assesses a link between auxin signaling and proteins involved in membrane trafficking.

The next paper is from Rothamsted Research and looks at how aerial differences in wheat cultivars can affect the root-associated microbiome. The sixth paper is from the James Hutton Institute and investigates the relationship between phosphate and zinc signaling during the growth of Brassica oleracea.

The final three papers focus on some aspect of plant mechanical strength. The first paper is from Aberystwyth and looks at the how mechanical stress impacts growth of Brachypodium. The next two papers are led from the US and Sweden respectively and include UK co-authors from Leeds, the JIC and York. The first looks at how lignin modifications illicits defence responses whilst the second begins to demonstrate how xyloglucan modifications alter secondary cell wall growth.


von Wangenheim D, Banda J, Schmitz A, Boland J, Bishopp A, Maizel A, Stelzer EHK, Bennett M (2020) Early developmental plasticity of lateral roots in response to asymmetric water availability. Nat Plants. doi: 10.1038/s41477-019-0580-z Open Access with link.

This brief communication is led by Daniel von Wangenheim, who worked with Malcolm Bennett and colleagues at the University of Nottingham. They use light sheet fluorescence microscopy to investigate how the local water environment controls the initiation of lateral root primordia. They show that this response is extremely plastic and that the initiation of pericycle cell files is linked to the external hydrological landscape. This study reveals a potential adaptive advantage when roots forage under heterogeneous soil conditions, which of course exists in all ‘real-world’ situations.

BotanyOne has written a nice blog about this paper and Daniel von Wangenheim has produced a superb explanatory video.


Escamez S, André D, Sztojka B, Bollhöner B, Hall H, Berthet B, Voß U, Lers A, Maizel A, Andersson M, Bennett M, Tuominen H (2020) Cell Death in Cells Overlying Lateral Root Primordia Facilitates Organ Growth in Arabidopsis. Curr Biol. doi: 10.1016/j.cub.2019.11.078 Open Access

Ute Voss and Malcolm Bennett from Nottingham are co-authors on this Finnish-led study in which Sacha Escamez is first author. They show that cell death occuring in advance of emerging lateral roots is an active developmental process rather than a passive effect of lateral root initiation. Plants with a cell-death-deficiency show delayed lateral root development, which is rescued through physical or genetic removal of outer cell files.


Qüesta JI, Antoniou-Kourounioti RL, Rosa S, Li P, Duncan S, Whittaker C, Howard M, Dean C (2020) Noncoding SNPs influence a distinct phase of Polycomb silencing to destabilize long-term epigenetic memory at Arabidopsis FLC. Genes Dev. doi: 10.1101/gad.333245.119 Open Access

This research from the John Innes Centre is led by Julia Qüesta and Rea Antoniou-Kourounioti. They show that four noncoding SNPs in the Lov-1 Arabidopsis accession are responsible for the reactivation of FLC after only a short cold treatment. They combine experimentation and modelling to also propose that the control of FLC reactivation is linked to the extent of DNA replication during the cold period.

Rea discusses this paper on the GARNet Community podcast. Look out for it on February 19th.


Xia L, Marquès-Bueno MM, Karnik RA (2020) Trafficking SNARE SYP132 Partakes in Auxin-associated Root Growth. Plant Physiol. doi: 10.1104/pp.19.01301 Open Access

This short communication is led by Lingfeng Xia in the Karnik lab at the University of Glasgow and looks at the role of auxin in the control of expression of the SNARE protein SYP132 during root growth and the gravitropic response. This linkage is indicative of an important role for membrane trafficking during the auxin response.


Kavamura VN, Robinson RJ, Hughes D, Clark I, Rossmann M, Melo IS, Hirsch PR, Mendes R, Mauchline TH (2020) Wheat dwarfing influences selection of the rhizosphere microbiome. Sci Rep. doi: 10.1038/s41598-020-58402-y
Open Access

Vanessa Kavamura is first author on this study led from Rothamsted Research that looks at how the aerial phenotypes of different wheat cultivars impacts root traits and the soil microbiome. Interestingly they show that taller wheat varieties are predicted to have a more connected bacterial network, which might lead to a more favourably rhizosphere for plant growth.


Pongrac P, Fischer S, Thompson JA, Wright G, White PJ (2020) Early Responses of Brassica oleracea Roots to Zinc Supply Under Sufficient and Sub-Optimal Phosphorus Supply. Front Plant Sci. doi: 10.3389/fpls.2019.01645 Open Access

Paula Pongrac is the first author on this study led from the James Hutton Institute in which they investigate how plants respond to their access to environmental phosphate and zinc. They assess gene expression of Brassica oleracea plants grown under different mineral conditions and reveal important relationships between the response to phosphorous and zinc that will inform future nutrient supply strategies and identification of novel germplasm.


Gladala-Kostarz A, Doonan JH, Bosch M (2020) Mechanical stimulation in Brachypodium distachyon: implications for fitness, productivity and cell wall properties. Plant Cell Environ. doi: 10.1111/pce.13724.

Agnieszka Gladala‐Kostarz who works with Maurice Bosch at Aberystwyth University is the first author on this research that looked at the effect of both wind- and mechanical- treatments on growth of two accessions of Brachypodium distachyon. They catalogue the physical changes that occur in this important base-line study that tracks the relevance of these environmental factors on the multiple growth traits.


Gallego-Giraldo L, Liu C, Pose-Albacete S, Pattathil S, Peralta AG, Young J, Westpheling J, Hahn MG, Rao X, Knox JP, De Meester B, Boerjan W, Dixon RA (2020) ARABIDOPSIS DEHISCENCE ZONE POLYGALACTURONASE 1 (ADPG1) releases latent defense signals in stems with reduced lignin content. Proc Natl Acad Sci U S A. doi: 10.1073/pnas.1914422117 Open Access

Lina Gallego-Giraldo is the first author on the US-led paper that includes Paul Knox and Sara Pose-Albacete from the University of Leeds. In this work they look at the link between lignin modifications and the inappropriate initiation of plant defence responses. They show that cell wall pectin remodeling mediated by the ARABIDOPSIS DEHISCENCE ZONE POLYGALACTURONASE 1 (ADPG1) protein releases defence elicitors and as such provides important information on the link between these processes.


Kushwah S, Banasiak A, Nishikubo N, Derba-Maceluch M, Majda M, Endo S, Kumar V, Gomez L, Gorzsás A, McQueen-Mason S, Braam J, Sundberg B, Mellerowicz EJ (2020) Arabidopsis XTH4 and XTH9 contribute to wood cell expansion and secondary wall formation. Plant Physiol. doi: 10.1104/pp.19.01529 Open Access

Sunita Kushwah leads this Swedish-study that has co-authors from the JIC and York. They investigate a novel role for the XTH4 and XTH9 xyloglucan endo-transglycosylase/ hydrolases during secondary growth in Arabidopsis. The activity of these enzymes has a significant effect on cell wall composition and in the control of wood formation

https://www.nottingham.ac.uk/biosciences/people/ute.voss

GARNet Research Roundup: Jan 24th 2020

The first GARNet Research Roundup of 2020 begins with a study from the University of Dundee at the James Hutton Institute in which they have adapted nanopore direct sequencing to analyse the Arabidopsis mRNA methylome. The second study is also from Dundee and is an analysis of alternative splicing in C4 sugarcane.

The next two papers look at the control of stomatal development. In the first, researchers from Bristol investigate the integration of temperature and light-induced signals whilst the second paper is from Sheffield and looks at the role, or lack thereof, of the HY5 protein. The fifth paper is also from Sheffield and looks at the role of the MALECTIN DOMAIN KINESIN 2 protein in dividing tissues.

The next two papers investigate the control of lateral root formation. Firstly researchers from Glasgow look at how potassium signaling integrates with both the mechanisms of RNA-directed DNA-methylation and the auxin response. The other paper looks at how auxin signaling integrates with the plasmodesmata development and includes co-authors from the University of Nottingham.

The eighth paper is led from Nottingham and looks at the role of the PROTEOLYSIS (PRT)1 during the plant immune response whilst the next paper, which is from the University of Cambridge, also looks at plant immunity, specifically at how the biosynthesis of phytic acid impacts this response.

The remaining four papers include UK-based co-authors from University of South Wales, Rothamsted and Cardiff, Durham, Oxford and Aberystwyth in international research teams led from Malaysian (the expression of Acyl-CoA-binding proteins in oil palm), China (the effect of silver nanoparticles on plant growth), Japan (convergent evolution of lateral organ formation) and Chile (the factors that influence grain filling in wheat) respectively.


Parker MT, Knop K, Sherwood AV, Schurch NJ, Mackinnon K, Gould PD, Hall AJ, Barton GJ, Simpson GG (2020) Nanopore direct RNA sequencing maps the complexity of Arabidopsis mRNA processing and m(6)A modification. Elife. doi: 10.7554/eLife.49658 Open Access

Matt Parker, Kasia Knop, Anya Sherwood and Nicholas Schurch are co-first authors on this study from the University of Dundee at the James Hutton Institute in which they perform direct RNA sequencing using a nanopore sequencer. They used this technical advance to analyse the mRNA (m6A) methylome and reveal a contribution to the control of the circadian clock. Future use of this technique will undoubtedly allow for an improved annotation of the Arabidopsis genome (and others).

https://elifesciences.org/articles/49658

Dantas LLB, Calixto CPG, Dourado MM, Carneiro MS, Brown JWS, Hotta CT (2019) Alternative Splicing of Circadian Clock Genes Correlates With Temperature in Field-Grown Sugarcane. Front Plant Sci. doi: 10.3389/fpls.2019.01614 Open Access

This study is led from Brazil with Luiza Dantas as first author and includes co-authors from the University of Dundee at the James Hutton Institute. They investigate the level of alternative splicing (AS) in commercial sugarcane, which is an important C4 crop. Tissue samples were collected in winter and summer and this analysis reveals temperature- and organ-dependent differences in the levels of AS across a set of genes under circadian control.


Kostaki KI, Coupel-Ledru A, Bonnell VC, Gustavsson M, Sun P, Mclaughlin FJ, Fraser DP, McLachlan DH, Hetherington AM, Dodd AN, Franklin KA (2020). Guard cells integrate light and temperature signals to control stomatal aperture. Plant Physiol. doi: 10.1104/pp.19.01528 Open Access

Kalliopi-Ioanna Kostaki is first author on this study from the University of Bristol that begins to unpick the mechanisms that integrate light and temperature signals in the control of stomatal development. These signals converge on phototropin photoreceptors and multiple members of the 14-3-3 protein family. This work also reveals a currently uncharacterised pathway that controls temperature regulation of guard cell movement.


Zoulias N, Brown J, Rowe J, Casson SA (2020) HY5 is not integral to light mediated stomatal development in Arabidopsis. PLoS One. doi: 10.1371/journal.pone.0222480 Open Access

Nick Zoulias is first author on this study from the Casson lab at University of Sheffield. ELONGATED HYPOCOTYL 5 (HY5) is a key regulator of light-mediated development yet in this study the authors show that the HY5-signaling cascade does not play a role in stomatal development. This key finding shows that phytochrome and cryptochrome signaling in guard cells is transmitted via non-HY5 signaling components.


Galindo-Trigo S, Grand TM, Voigt CA, Smith LM (2020) A malectin domain kinesin functions in pollen and seed development in Arabidopsis. J Exp Bot doi: 10.1093/jxb/eraa023
This research from the Smith lab at the University of Sheffield is led by Sergio Galindo-Trigo. They show that MALECTIN DOMAIN KINESIN 2 (MDKIN2) is involved in pollen, embryo and endosperm development. Malectin domains bind polysaccharides and peptides when found extracellularly in receptor-like kinases so this might suggest that in dividing tissues MDKIN2 plays a role during the physical division of cells.


Shahzad Z, Eaglesfield R, Carr C, Amtmann A (2020) Cryptic variation in RNA-directed DNA-methylation controls lateral root development when auxin signalling is perturbed. Nat Commun. doi: 10.1038/s41467-019-13927-3 Open Access

Zaigham Shahzad at the University of Glasgow is the first author in this study that looks at the relationship between potassium deficiency and lateral root formation. This effect is mediated via the impact of CLSY1, a key component of the RNA-directed DNA-methylation machinery, on the transcriptional repression of the AuxIAA protein IAA27. Interestingly this system appears to act as a backup to the auxin-dependent proteolysis pathway that is primarily responsible for the control of IAA27 activity.


Sager R, Wang X, Hill K, Yoo BC, Caplan J, Nedo A, Tran T, Bennett MJ, Lee JY (2020) Auxin-dependent control of a plasmodesmal regulator creates a negative feedback loop modulating lateral root emergence. Nat Commun. doi: 10.1038/s41467-019-14226-7.

This US study is led by Ross Sager and includes co-authors from the University of Nottingham. This research links the role of auxin in lateral root formation with plasmodesmata development through control of the plasmodesmal regulator PDLP5. They present a model wherein molecules required for lateral root emergence transit through plasmodesmata following an inductive auxin signal.


Till CJ, Vicente J, Zhang H, Oszvald M, Deery MJ, Pastor V, Lilley KS, Ray RV, Theodoulou FL, Holdsworth MJ (2019) The Arabidopsis thaliana N-recognin E3 ligase PROTEOLYSIS1 influences the immune response. Plant Direct. doi: 10.1002/pld3.194 Open Access

Christopher Till, Jorge Vicente and Hongtao Zhangis are co-first authors on this research led from the University of Nottingham and Rothamsted Research that involves use of quantitative proteomics to define the role of the N-recognin E3 ligase PROTEOLYSIS (PRT)1 during the plant immune response.


Poon JSY, Le Fevre RE, Carr JP, Hanke DE, Murphy AM (2019) Inositol hexakisphosphate biosynthesis underpins PAMP-triggered immunity to Pseudomonas syringae pv. tomato in Arabidopsis thaliana but is dispensable for establishment of systemic acquired resistance. Mol Plant Pathol. doi: 10.1111/mpp.12902
This research from the University of Cambridge is led by Jacquelyne Poon and Alex Murphy and looks at the role of the phytic acid (inositol hexakisphosphate, InsP6) biosynthesis in dividing tissues during the plant immune response. They characterize Arabidopsis plants with mutations in biosynthetic enzymes to show that there are multiple mechanisms of basal resistance that are dependent upon InsP6.


Amiruddin N, Chan PL, Azizi N, Morris PE, Chan KL, Ong PW, Rosli R, Masura SS, Murphy DJ, Sambanthamurthi R, Haslam RP, Chye ML, Harwood JL, Low EL (2019) Characterisation of Oil Palm Acyl-CoA-Binding Proteins and Correlation of their Gene Expression with Oil Synthesis. Plant Cell Physiol. doi: 10.1093/pcp/pcz237.
Nadzirah Amiruddin is lead author on this Malaysian-led research that includes collaborators from the University of South Wales, Rothamsted Research and Cardiff University. This paper looks at the expression of Acyl-CoA-binding proteins (ACBPs) in oil palm; providing important information about the role of this protein family during oil synthesis in the world’s most important oil crop.


Wang L, Sun J, Lin L, Fu Y, Alenius H, Lindsey K, Chen C (2019) Silver nanoparticles regulate Arabidopsis root growth by concentration-dependent modification of reactive oxygen species accumulation and cell division. Ecotoxicol Environ Saf. doi: 10.1016/j.ecoenv.2019.110072.

This Chinese-study is led by Likai Wang and includes Keith Lindsey from Durham University as a co-author. They look at the effect of silver nanoparticles (AgNPs) on growth of Arabidopsis. AgNPs are taken up by roots and have opposing effects at either 50 mg L-1 or 100mg mg L-1. This is an important preliminary study to understand how plant growth might be altered if AgNP’s are used as a delivery mechanism.


Naramoto S, Jones VAS, Trozzi N, Sato M, Toyooka K, Shimamura M, Ishida S, Nishitani K, Ishizaki K, Nishihama R, Kohchi T, Dolan L, Kyozuka J (2019) A conserved regulatory mechanism mediates the convergent evolution of plant shoot lateral organs. PLoS Biol. 2019 doi: 10.1371/journal.pbio.3000560 Open Access

This Japanese study is led by Satoshi Naramoto and Junko Kyozuka and includes co-authors from the University of Oxford. They performed a mutant screen in the liverwort Marchantia polymorpha to identify the LATERAL ORGAN SUPRESSOR 1 (MpLOS1) gene, which regulates meristem maintenance and lateral organ development. Remarkably they showed this gene is also functions in the control of lateral organ development in rice, therefore demonstrating convergent evolution across plant lineages in the control of lateral organs.


Del Pozo A, Méndez-Espinoza AM, Romero-Bravo S, Garriga M, Estrada F, Alcaíno M, Camargo-Rodriguez AV, Corke FMK, Doonan JH, Lobos GA (2020) Genotypic variations in leaf and whole-plant water use efficiencies are closely related in bread wheat genotypes under well-watered and water-limited conditions during grain filling. Sci Rep. doi: 10.1038/s41598-019-57116-0 Open Access

Alejandro del Pozo leads this Chilean study that includes co-authors from Aberystwyth and NIAB. This large-scale glasshouse experiment looked at the effect of water deficit on the growth of 14 bread wheat genotypes. Measurement of multiple parameters revealed that plants face limitations to the assimilation process during grain filling due to natural senesce and water stress.

GARNet Research Roundup: July 26th 2019

This summer-time-reading bumper edition of the GARNet Research Roundup begins with two papers from the University of Sheffield that each use advanced imaging techniques. Firstly Andrew Fleming’s group leads a study on the link between stomatal function and mesophyll space morphology. Second is a study from Matthew Johnson’s group that looks at the dynamic arrangement of thylakoid stacks.

Next are two papers that include Alison Smith from the JIC as a corresponding author. The first also includes Vasilios Andriotis from the University of Newcastle and looks at the role of the plastidial pentose phosphate pathway during post-germination growth. Second uses a gene-editing strategy to generate potatoes with altered starch morphologies.

The fifth paper also looks at starch; researchers from Cambridge and Norwich are involved in a study that characterises the role of the LIKE SEX4 1 protein in starch degradation.

The sixth paper is from Aberystwyth University and identifies a transcription factor that alters secondary cell wall composition in Brachypodium and maize. Next is research from the University of Bath that looks at the role of a protein S-acyl transferase during seed germination.

The eighth and ninth papers are led by Spanish research groups and include contributions from UK-based co-authors in Cambridge and Nottingham, working on photoperiod perception or phosphate signaling respectively.

The tenth paper features work from Cardiff University and looks at the role of heterologous expression of the Arabidopsis WEE1 protein. The Bancroft lab from the University of York leads the next paper that investigates glucosinolate signaling in Brassica napus.

The final three manuscripts are methods papers. The first from Edinburgh introduces a new NanoLUC reporter whilst the other two include techniques involved in the investigation of light-regulated growth processes.


Lundgren MR, Mathers A, Baillie AL, Dunn J, Wilson MJ, Hunt L, Pajor R, Fradera-Soler M, Rolfe S, Osborne CP, Sturrock CJ, Gray JE, Mooney SJ, Fleming AJ (2019) Mesophyll porosity is modulated by the presence of functional stomata. Nat Commun. doi: 10.1038/s41467-019-10826-5

Open Access

This UK-wide study is led from Andrew Fleming’s lab in Sheffield and includes Marjorie Lundgren as first author (now working in Lancaster). They use microCT imaging alongside more traditional measurements linked to analysis of gas exchange to show that mesophyll airspace formation is linked to stomatal function in both Arabidopsis and wheat. This allows the authors to propose that coordination of stomata and mesophyll airspace pattern underpins water use efficiency in crops.

https://www.nature.com/articles/s41467-019-10826-5

Wood WH, Barnett SFH, Flannery S, Hunter CN, Johnson MP (2019) Dynamic thylakoid stacking is regulated by LHCII phosphorylation but not its interaction with photosystem I. Plant Physiol. doi: 10.1104/pp.19.00503

Open Access

William Wood is the first author on this study from the University of Sheffield that uses 3D structured illumination microscopy (3D-SIM) to look at the dynamics of thylakoid stacking in both Arabidopsis and spinach. They show that the processes they observe are dependent on light harvesting complex II phosphorylation.

http://www.plantphysiol.org/content/early/2019/06/11/pp.19.00503.long

Andriotis VME, Smith AM (2019) The plastidial pentose phosphate pathway is essential for postglobular embryo development in Arabidopsis. Proc Natl Acad Sci U S A. doi: 10.1073/pnas.1908556116

Open Access

Vasilios Andriotis (now at the University of Newcastle) is the lead author of this work performed in Alison Smith’s lab at the JIC. They look at the role of the plastidial oxidative pentose phosphate pathway (OPPP) during embryo development. This involved demonstrating that production of ribose-5-phosphate (R5P), which in turn leads to synthesis of purine nucleotides, is a critical function of the OPPP.


Tuncel A, Corbin KR, Ahn-Jarvis J, Harris S, Hawkins E, Smedley MA, Harwood W, Warren FJ, Patron NJ, Smith AM (2019) Cas9-mediated mutagenesis of potato starch-branching enzymes generates a range of tuber starch phenotypes. Plant Biotechnol J. doi: 10.1111/pbi.13137

Open Access

Alison Smith and Nicola Patron who work in Norwich Research Park are corresponding authors of this study that includes Aytug Tuncel as first author. They have used Cas9-mediated gene editing to generate potato plants that have a range of different tuber starch structures. This shows that gene-editing techniques allows the transgene-free alteration to generate potentially healthier crops.


Schreier TB, Umhang M, Lee SK, Lue WL, Shen Z, Silver D, Graf A, Müller A, Eicke S, Stadler M, Seung D, Bischof S, Briggs SP, Kötting O, Moorhead GB, Chen J, Zeeman SC (2019) LIKE SEX4 1 acts as a β-amylase-binding scaffold on starch granules during starch degradation. Plant Cell. doi: 10.1105/tpc.19.00089

Open Access

Tina Schreier from the University of Cambridge is the first author on this international study led from Switzerland that also includes Alexander Graf and David Seung from the JIC as co-authors. This study defines a precise role for the LIKE SEX FOUR 1 (LSF1) protein that binds starch and is required for normal starch degradation. Through a variety of experiments they show that the glucan binding, rather than phosphatase activity, is required for LSF1 function during starch degradation.


Bhatia R, Dalton S, Roberts LA, Moron-Garcia OM, Iacono R, Kosik O, Gallagher JA, Bosch M (2019) Modified expression of ZmMYB167 in Brachypodium distachyon and Zea mays leads to increased cell wall lignin and phenolic content. Sci Rep. doi: 10.1038/s41598-019-45225-9

Open Access

Rakesh Bhatia is the first author on this work from the lab of Maurice Bosch at Aberystwyth University. They overexpress the maize MYB transcription factor ZmMYB167 in both Brachypodium and maize. Both species show increased lignin content with Brachypodium but not maize showing a biomass deficit. This indicates that ZmMYB167 could be a useful molecular tool for the alteration of secondary cell wall biosynthesis.

https://www.nature.com/articles/s41598-019-45225-9

Li Y, Xu J, Li G, Wan S, Batistic O, Sun M, Zhang Y, Scott R, Qi B (2019) Protein S-acyl Transferase 15 is Involved in Seed Triacylglycerol Catabolism during Early Seedling Growth in Arabidopsis (2019) J Exp Bot. doi: 10.1093/jxb/erz282

First author on this UK-Chinese collaboration is Yaxiao Li who works with Baoxiu Qi at the University of Bath. The authors characterise the function of Arabidopsis Protein Acyl Transferase 15, AtPAT15. This protein is involved in essential β-oxidation of triacylglycerols during post-germination growth.


Ramos-Sánchez JM, Triozzi PM, Alique D, Geng F, Gao M, Jaeger KE, Wigge PA, Allona I, Perales M (2019) LHY2 Integrates Night-Length Information to Determine Timing of Poplar Photoperiodic Growth. Curr Biol. doi: 10.1016/j.cub.2019.06.003

Open Access

This Spanish-led study includes co-authors from the Sainsbury Laboratory in Cambridge and attempts to define the factors that control photoperiod perception in trees, using poplar as a model system. FLOWERING LOCUS T2 (FT2) has been previously shown to be involved in this process and this study builds on that work to show that night-length information is transmitted by the clock gene LATE ELONGATED HYPOCOTYL 2 (LHY2) and is able to control FT2 expression.

https://www.cell.com/current-biology/fulltext/S0960-9822(19)30696-7?

Silva-Navas J, Conesa CM, Saez A, Navarro-Neila S, Garcia-Mina JM, Zamarreño AM, Baigorri R, Swarup R, Del Pozo JC (2019) Role of cis-zeatin in root responses to phosphate starvation. New Phytol. doi: 10.1111/nph.16020

Ranjan Swarup from the University of Nottingham is a co-author on this Spanish-led study that has Javier Silva-Navas as first author. Through analysis of dark-grown seedlings they have identified a set of new genes involved in root phosphate signaling. In addition they provide evidence of a links between cytokinin and phosphate signaling through modulation of the cell cycle.


Siciliano I, Lentz Grønlund A, Ševčíková H, Spadafora ND, Rafiei G, Francis D, Herbert RJ, Bitonti MB, Rogers HJ, Lipavská H (2019) Expression of Arabidopsis WEE1 in tobacco induces unexpected morphological and developmental changes. Sci Rep. 2019 Jun 18;9(1):8695. doi: 10.1038/s41598-019-45015-3

Open Access

Ilario Siciliano leads this work that includes colleagues from Hilary Rogers’ lab at Cardiff University. The WEE1 protein regulates the cell cycle across eukaryote lineages. In this work they show that overexpression of AtWEE1 in tobacco causes precocious flowering and increased shoot morphogenesis of stem explants whilst in cell culture this WEE1 OX causes smaller cell sizes.


Kittipol V, He Z, Wang L, Doheny-Adams T, Langer S, Bancroft I (2019) Genetic architecture of glucosinolate variation in Brassica napus. J Plant Physiol. doi: 10.1016/j.jplph.2019.06.001

Open Access

This study from the Bancroft lab at the University of York is led by Varanya Kittipol. Through use of Associative Transcriptomics (AT) across a diversity panel of 288 Brassica napus genotypes they are able to identify a set of genes involved in synthesis of glucosinate hydrolysis products.


Urquiza-García U, Millar AJ (2019). Expanding the bioluminescent reporter toolkit for plant science with NanoLUC. Plant Methods. doi: 10.1186/s13007-019-0454-4

Open Access

This study from the University of Edinburgh introduces NanoLUC, a new more stable luciferase-based reporter for use by the plant community.

The final two papers are methods papers that focus on different aspects of light-regulated growth. These are from the University of Southampton and University of York.

https://plantmethods.biomedcentral.com/articles/10.1186/s13007-019-0454-4

Terry MJ, Kacprzak SM (2019) A Simple Method for Quantification of Protochlorophyllide in Etiolated Arabidopsis Seedlings. Methods Mol Biol. doi: 10.1007/978-1-4939-9612-4_14

Oakenfull RJ, Ronald J, Davis SJ (2019) Measuring Phytochrome-Dependent Light Input to the Plant Circadian Clock. Methods Mol Biol. doi: 10.1007/978-1-4939-9612-4_15

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: December 7th 2018

The first four papers in this GARNet Research Roundup includes research from Norwich Research Park. Firstly members of Jonathan Jones’ lab have identified a new Avr gene from Hyaloperonospora arabidopsidis. Secondly Anne Osbourn’s lab characterises two novel arabinosyltransferases that are involved in the plant defence response. Thirdly Cathie Martin’s group is involved in a study that investigates the biosynthesis of the metabolite ubiquinone. Finally in research from NRP is from Silke Robatzek’s lab, where they use a novel quantitative imaging system to characterise stomatal mutants.

The next two papers arise from work at SLCU, firstly looking at the possible role of a novel transposon family during gene-shuffling and secondly a paper that investigates the structure of an important component of the strigolactone signaling pathway.

The seventh paper from Peter Eastmond’s lab at Rothamsted Research identifies a novel gene involved in seed oil composition. The penultimate paper is from Peter Unwin at the University of Leeds and assesses the cell wall composition of ‘giant’ root cells induced by nematode Meloidogyne spp. Finally is a methods paper that describes how microCT imaging can be used to measure different leaf parameters.


Asai S, Furzer O, Cavik V, Kim DS, Ishaque N, Goritschnig S, Staskawicz B, Shirasu K, Jones JDG (2018) A downy mildew effector evades recognition by polymorphism of expression and subcellular localization. Nature Communications doi: 10.1038/s41467-018-07469-3

https://www.nature.com/articles/s41467-018-07469-3

Open Access

Shuta Asai from Jonathan Jones’ lab at The Sainsbury Lab, Norwich is the lead-author on this study that looks at co-evolution of host and pathogen resistance genes. The relationship between Hyaloperonospora arabidopsidis (Hpa) and Arabidopsis is defined by the gene-for-gene model of host Resistance (R) genes and pathogen Avirulence (AVR) genes. In this study the authors identify the HaRxL103Emoy2 AVR gene that is recognised by the R gene RPP4 and how this resistance is broken by altered expression or cellular localization.


Louveau T, Orme A, Pfalzgraf H, Stephenson M, Melton RE, Saalbach G, Hemmings  AM, Leveau A, Rejzek M, Vickerstaff RJ, Langdon T, Field R, Osbourn AE (2018) Analysis of two new arabinosyltransferases belonging to the carbohydrate-active enzyme (CAZY) glycosyl transferase family 1 provides insights into disease resistance and sugar donor specificity. Plant Cell. doi: 10.1105/tpc.18.00641

Open Access

This research from the John Innes Centre, East Maling and Aberystwyth University is led by Thomas Louveau and Anne Osbourn and characterises two new arabinosyltransferases from oat and soybean. These enzymes are involved in the production of saponins that are involved in defence responses. These enzymes normally transfer arabinose to their substrates but through targeted mutations the authors modified one of them to instead transfer glucose. This study provides insights into the specifics of ‘sugar-donation’ and has identified potential novel targets for manipulating defence responses in two crop species.


Soubeyrand E, Johnson TS, Latimer S, Block A, Kim J, Colquhoun TA, Butelli E,  Martin C, Wilson MA, Basset G (2018) The Peroxidative Cleavage of Kaempferol Contributes to the Biosynthesis of the Benzenoid Moiety of Ubiquinone in Plants. Plant Cell. 2018 Nov 14. pii: tpc.00688.2018. doi: 10.1105/tpc.18.00688

Open Access

This US-led study includes members of Cathie Martin’s lab at the John Innes Centre as co-authors in which they investigate the flavonoid-biosynthesis pathway, in particular the land-plant-specific synthesis of ubiquinone. They used Arabidopsis and tomato mutants to dissect the ubiquinone biosynthesis pathway, revealing that the B-ring of the specalised metabolite kaempferol is incorporated into the primary metabolite ubiquinone.


Bourdais G, McLachlan DH, Rickett LM, Zhou J, Siwoszek A, Häweker H, Hartley M, Kuhn H, Morris RJ, MacLean D, Robatzek S (2018) The use of quantitative imaging to investigate regulators of membrane trafficking in Arabidopsis stomatal closure. Traffic. doi: 10.1111/tra.12625

This work from both Norwich Research Park and the University of Bristol is led by Gildas Bourdais and describes a high-throughput quantitative imaging, reverse genetic screen to characterize known stomatal mutants on the basis of their effect on the endomembrane system. This screen allowed them to precisely define the point in the signaling pathway at which each mutant was affected, providing a genetic framework for the control of stomatal closure. This image-based tool should be a valuable addition to future studies that aim to use quantitative image analysis.


https://academic.oup.com/nar/advance-article/doi/10.1093/nar/gky1196/5198529

Catoni M, Jonesman T, Cerruti E, Paszkowski J (2018) Mobilization of Pack-CACTA transposons in Arabidopsis suggests the mechanism of gene shuffling (2018) Nucleic Acids Res. doi: 10.1093/nar/gky1196

Open Access

This work was performed at SLCU in Jerzy Paszkowski’s lab by current University of Birmingham lecturer Marco Catoni and analyses the genomic impact of the mobilisation of Pack-TYPE transposons. They track the movement of these transposons over multiple generations, showing that they can insert into genic regions and that their subsequent incomplete excisions can cause deleterious effect on gene function. Over evolutionary time the action of this type of mobile element might therefore importantly influence gene shuffling.


Shabek N, Ticchiarelli F, Mao H, Hinds TR, Leyser O, Zheng N (2018) Structural plasticity of D3-D14 ubiquitin ligase in strigolactone signalling. Nature. doi: 10.1038/s41586-018-0743-5

Nitzan Shabek is the lead author on his US-led paper that includes Fabrizio Ticchiarelli and Ottoline Leyser from SLCU as co-authors. This paper reveals the structure of the interaction between the Arabidopsis α/β hydrolase D14 and the D3 F-box protein, which is important for multiple aspects of strigolactone signaling. They show that structural plasticity of the D3 C-terminal α-helix, which can switch between two different forms, enables the interaction between D14 and the D53 repressor protein. Providing insight into these specific interactions is key to increasing understanding of how the D14-D3 complex influences strigolactone signaling.


Menard GN, Bryant FM, Kelly AA, Craddock CP, Lavagi I, Hassani-Pak K, Kurup S, Eastmond PJ (2018) Natural variation in acyl editing is a determinant of seed storage oil composition. Sci Rep. doi: 10.1038/s41598-018-35136-6

Open Access

This work is led from Rothamsted Research with Guillaume Menard as first author and uses the Arabidopsis MAGIC population to identify novel genetic loci involved in seed oil composition. They identified multiple QTLs associated with the quantity of the major very long chain fatty acid species 11-eicosenoic acid (20:1), showing that the enzyme LYSOPHOSPHATIDYLCHOLINE ACYLTRANSFERASE 2 (LPCAT2), which is involved in the acyl-editing pathway, was the primary QTL. Subsequently they show LPCAT2 expression was key for varying seed 20:1 content and that natural variation in the capacity for acyl editing is an important determinant of oil content.


Bozbuga R, Lilley CJ, Knox JP, Urwin PE (2018) Host-specific signatures of the cell  wall changes induced by the plant parasitic nematode, Meloidogyne incognita (2018). Sci  Rep. doi: 10.1038/s41598-018-35529-7

https://www.nature.com/articles/s41598-018-35529-7

Open Access

Refik Bozbuga at the University of Leeds is first author on this study that investigates the cell wall composition of nutrient-supplying ‘giant cells’ that are induced in roots following infection with Meloidogyne spp nematodes. They analysed the cell walls of giant cells from three species (Arabidopsis, maize and aduki bean) as well as using a set of Arabidopsis mutants to characterise the possible cell wall components that might influence infection rates.


Mathers AW, Hepworth C, Baillie AL, Sloan J, Jones H, Lundgren M, Fleming AJ,  Mooney SJ, Sturrock CJ (2018) Investigating the microstructure of plant leaves in 3D with lab-based X-ray computed tomography. Plant Methods. doi:  10.1186/s13007-018-0367-7

Open Access
This paper from the Universities of Nottingham, Sheffield and Lancaster provides a methodology that uses a microCT image pipeline to measure leaf intercellular airspace and to provide quantitative data on descriptors of leaf cellular architecture. They measured 6 different plant species, showing that this 3D method generates an improved dataset when compared to traditional 2D methods of measurement.

https://plantmethods.biomedcentral.com/articles/10.1186/s13007-018-0367-7

GARNet Research Roundup: July 16th

This week’s GARNet research roundup begins with a set of papers looking at aspects of the plant defence response with a focus on the cell wall. Firstly work from Mike Deeks’ lab in Exeter assesses the role of FORMIN4 during pre-invasion cell wall apposition. Secondly Sara Pose and Paul Knox (Leeds) are involved with a study looking at how altered cell wall lignin composition alters the defense response. Finally Joe McKenna and Cyril Zipfel are co-authors on a Norwegian-led study that looks at the influence of plant cell wall integrity maintenance in immune signalling.

Relatedly is a study from the Devoto lab at RHUL looks at the role of the defence hormone methyl jasmonate in Arabidopsis cell culture.

Next are two papers that research different aspects of the plant ER. Verena Kriechbaumer (Oxford Brookes) looks at plant ER-localised Lunapark proteins whilst a study from the University of Warwick provides a preliminary structural analysis of the RTNLB13 reticulon protein.

The seventh and eight papers are involved with the plant response to different growth conditions. Research from University of Nottingham looks at the response of the cortical cell layer of the root meristem to low phosphate conditions whilst work from University of Southampton investigates the relationship between nitrate and copper signaling.

The next paper is from Emily Flashman’s lab at the University of Oxford and looks at the role of plant cysteine oxidases as oxygen sensors whilst the tenth paper features John Doonan (Aberystwyth University) as a co-author and investigates how a histone acetyltransferase affects trichome development.

Finally is a paper from Pierre Baudal and Kirsten Bomblies (John Innes Centre) that uses Arabidopsis arenosa as a model to investigate the emergence of novel flowering time alleles in populations that have colonised along railway corridors.


Sassmann S, Rodrigues C, Milne SW, Nenninger A, Allwood E, Littlejohn GR, Talbot NJ, Soeller C, Davies B, Hussey PJ, Deeks MJ (2018) An Immune-Responsive Cytoskeletal-Plasma Membrane Feedback Loop in Plants. Curr Biol. doi: 10.1016/j.cub.2018.05.014

https://www.sciencedirect.com/science/article/pii/S096098221830616X?via%3Dihub

Open Access

Stefan Sassmann is the lead author of this paper from Mike Deeks’s lab in Exeter. They investigate the role of the membrane-integrated FORMIN4 protein in the process of cell wall apposition, which occurs as part of the plant immune response and is dependent on actin dynamics. FORMIN4 is stably localised apart from the active traffic of the endomembrane system and removing its function compromises the defense response, presumably by altering actin distribution at sites of cell wall apposition. This work demonstrates that FORMIN4 acts as a key component of the pre-invasion defense response.


Gallego-Giraldo L, Posé S, Pattathil S, Peralta AG, Hahn MG, Ayre BG, Sunuwar J, Hernandez J, Patel M, Shah J, Rao X, Knox JP, Dixon RA (2018) Elicitors and defense gene induction in plants with altered lignin compositions. New Phytol. doi: 10.1111/nph.15258

Open Access

Sara Pose and Paul Knox (University of Leeds) are co-authors on this US-led study that investigates how lignin composition can influence the defence response. Plants with the same lignin content but changed lignin compositions show altered expression in genes involved with different arms of the defense response. This indicates that cell wall lignin composition plays a significant role in the plants ability to response to different sources of pathogen attack.


Engelsdorf T, Gigli-Bisceglia N, Veerabagu M, McKenna JF, Vaahtera L, Augstein F, Van der Does D, Zipfel C, Hamann T (2018) The plant cell wall integrity maintenance and immune signaling systems cooperate to control stress responses in Arabidopsis thaliana. Sci Signal. doi: 10.1126/scisignal.aao3070

Joe McKenna (Imperial College, now Oxford Brookes University) and Cyril Zipfel (The Sainsbury Laboratory, Norwich) are co-authors on this Norwegian-led study that looks at the plant cell wall integrity maintenance mechanism and how it responses to the challenges of growth, development and environmental stresses. They identified a set of receptor-like kinases that are key for the responses elicted by cell wall damage (CWD). Conversely they showed that the components of the pattern-triggered immunity (PTI) signaling pathway repress responses to CWD. This study provides insights into how cell wall responses interact with downstream gene expression changes following pathogen challenge.


Bömer M, O’Brien JA, Pérez-Salamó I, Krasauskas J, Finch P, Briones A, Daudi A, Souda P, Tsui TL, Whitelegge JP, Paul Bolwell G, Devoto A (2018) COI1-dependent jasmonate signalling affects growth, metabolite production and cell wall protein composition in Arabidopsis. Ann Bot. doi: 10.1093/aob/mcy109

Open Access

Moritz Bömer works with Alessandra Devoto at Royal Holloway University of London and leads this research that looks at the effect of MeJA treatment on growth and gene expression in Arabidopsis cell culture. They demonstrate that both MeJA treatment or COI1 overexpression causes changes in the abundance of proteins involved in cell wall loosening as well as altered levels of primary metabolites alanine, serine and succinic acid. This work demonstrates a close link between hormone signaling, the defence response and the metabolic profile of Arabidopsis cells.

Dr Devoto and her academic colleagues at RHUL are profiled in the latest GARNish newsletter available for download from the GARNet website.


Kriechbaumer V, Breeze E, Pain C, Tolmie F, Frigerio L, Hawes C (2018) Arabidopsis Lunapark proteins are involved in ER cisternae formation. New Phytol. doi: 10.1111/nph.15228

https://nph.onlinelibrary.wiley.com/doi/abs/10.1111/nph.15228

Open Access

Verena Kriechbaumer from Oxford Brookes University leads this research that investigates the in planta function of novel ER network-shaping proteins called Lunaparks (LNP). They show that these proteins localise to the entire ER network in Arabidopsis. They use confocal microscopy to show that altering the level of LNP gene expression changes ER morphology, possibly by regulating the formation of ER cisternae.


Chow M, Sklepari M, Frigerio L, Dixon AM (2018) Bacterial expression, purification and biophysical characterization of the smallest plant reticulon isoform, RTNLB13 Protein Expr Purif. doi: 10.1016/j.pep.2018.06.015

Open Access

Michael Chow worked with Lorenzo Frigerio and Ann Dixon at the University of Warwick to provide a preliminary structure and topology analysis of the plant RTNLB13 reticulon protein. This ER-associated integral membrane protein was expressed in bacteria and then a variety of analysis techniques were used to suggest that RTNLB13 has a high level of self-association and protein-membrane interactions.


Janes G, von Wangenheim D, Cowling S, Kerr I, Band L, French AP, Bishopp A (2018) Cellular Patterning of Arabidopsis Roots Under Low Phosphate Conditions Front Plant Sci. doi: 10.3389/fpls.2018.00735

https://www.frontiersin.org/articles/10.3389/fpls.2018.00735/full

Open Access

George Janes works with Anthony Bishopp at the University of Nottingham and leads this study that looks at root meristem development under low phosphate conditions. They show that in phosphate-limiting conditions the cortex layer of the root meristem contains almost double the number of cells, which results in a greater number of root hair-forming epidermal cells. As this change can occur within 24hrs the rapidity of the response represents a significant adaptation to a changing root environment.


Hippler FWR, Mattos-Jr D, Boaretto RM, Williams LE (2018) Copper excess reduces nitrate uptake by Arabidopsis roots with specific effects on gene expression J Plant Physiol. doi: 10.1016/j.jplph.2018.06.005

https://www.sciencedirect.com/science/article/pii/S0176161718302888

Open Access

Franz Hippler (University of Southampton) leads this UK-Brazil collaboration showing that growth of Arabidopsis plants in excess copper conditions causes a downregulation in nitrate uptake. This is due to both direct and indirect changes on the gene expression of nitrate transporters as well as a reduction in transcript level of the plasma membrane proton pump, AHA2. This effect was altered when copper levels were reduced demonstrating that copper toxicity acts at the level of nitrate transport and homeostasis.


White MD, Kamps JJAG, East S, Taylor Kearney LJ, Flashman E (2018) The Plant Cysteine Oxidases from Arabidopsis thaliana are kinetically tailored to act as oxygen sensors J Biol Chem.

doi: 10.1074/jbc.RA118.003496

Open Access

Mark White is the lead author on this work from the lab of Emily Flashman at the University of Oxford in which they look at the role of plant cysteine oxidases (PCOs) as oxygen sensors. They assessed the kinetics of each of AtPCO1 to AtPCO5 proteins and show that the most catalytically competent isoform is AtPCO4, in terms of both responding to O2, and oxidizing hypoxic responsive proteins. This work validates an O2-sensing role for the PCOs and provides evidence for functional differences between members of this enzyme family.


Kotak J, Saisana M, Gegas V, Pechlivani N, Kaldis A, Papoutsoglou P, Makris A, Burns J, Kendig AL, Sheikh M, Kuschner CE, Whitney G, Caiola H, Doonan JH, Vlachonasios KE, McCain ER, Hark AT (2018) The histone acetyltransferase GCN5 and the transcriptional coactivator ADA2b affect leaf development and trichome morphogenesis in Arabidopsis. Planta. doi: 10.1007/s00425-018-2923-9 Open Access

John Doonan (Aberystwyth University) is a co-author on this manuscript led by Jenna Kotak and Amy Herd in the USA. They investigate plants that have mutations in the histone acetyltransferase GCN5 and associated transcriptional coactivator ADA2b. These genes have been previously demonstrated as being involved in endoreduplication and trichome branching. They show that these mutants have alterations in the number and patterning of trichome-branches and that ADA2b and GCN5 are required to couple nuclear content with cell growth and morphogenesis.


Baduel P, Hunter B, Yeola S, Bomblies K. Genetic basis and evolution of rapid cycling in railway populations of tetraploid Arabidopsis arenosa (2018) PLoS Genet.

doi: 10.1371/journal.pgen.1007510 Open Access

Pierre Baduel and Kirsten Bomblies (John Innes Centre) lead this work that was conducted prior to Kirsten’s move to Norwich. In this study they follow the colonization of populations of Arabidopsis arenosa along mountain railway corridors. They demonstrate that selective pressure has occurred on novel alleles of flowering time genes and discuss the implications for ruderal communities linked to railways as allele conduits linked to local adaptations.

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 colleagues 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: July 11th

After a conference break the Arabidopsis Research Roundup returns with an outstanding selection of papers from UK (and mostly Scotland-based) researchers. Firstly Levi Yant provides an audio description of work that has identified important loci for adaption to harsh environments. Secondly John Doonan leads a multi-national group investigating the role of eiF4A phosphorylation within proliferating cells. Next two Scottish-based studies both investigate aspects of light signalling on different scales: a Glasgow-based consortium dissects the UVR8 signaling module while the role of phytochrome on global carbon allocation is studied by Karen Halliday’s group in Edinburgh. The final paper also involves significant Scottish involvement with Piers Hemsley at Dundee together with Simon Turner at Manchester investigating the role of s-acylation in the activity of the cellulose synthase complex.

Arnold BJ, Lahner B, DaCosta JM, Weisman CM, Hollister JD, Salt DE, Bomblies K, Yant L (2016) Borrowed alleles and convergence in serpentine adaptation. PNAS http://dx.doi.org/10.1073/pnas.1600405113 Open Access

New investigator at the John Innes Centre, Levi Yant, is the corresponding author on this study that also includes contributions from the labs of Kristen Bomblies and current GARNet Chairman David Salt. This investigation uses GWAS techniques to identify loci in Arabidopsis Arenosa that are important for growth on serpentine barrens, which are characterised by drought, mineral paucity and high levels of heavy metals. They showed that polygenic multi-trait genomic locations are important for serpentine adaptation. The authors reassessed previous independent datasets and showed that 11 loci have been identified across these studies and are therefore good candidates as drivers of convergent evolution. This study provides evidence that certain A.arenosa alleles have been introgressed from A.lyrata and that these may facilitate adaptation to a multi-hazard environment.

Levi kindly provides a short audio description of this work, that also touches on ionomics and data reuse!

Bush MS, Pierrat O, Nibau C, Mikitova V, Zheng T, Corke FM, Vlachonasios K, Mayberry LK, Browning KS, Doonan JH (2016) eIF4A RNA Helicase Associates with Cyclin-Dependent Protein Kinase A in Proliferating Cells and is Modulated by Phosphorylation Plant Physiol. http://dx.doi.org/10.1104/pp.16.00435 Open Access

eif4apic
Growth of phospho-null or phospho-mimetic mutants of eif4a1

John Doonan (Aberystwyth) is the leader of this wide collaboration of UK, US, Czech, Greek and Chinese researchers that investigate the interaction of the eIF4A RNA helicase with cyclin-dependent protein kinase A (CDKA). This interaction only occurs in proliferating cells where CDKA acts by phosphorylating specific amino acids on eIF4A. Throughout in vivo and in vitro experiments using phospho-null and phosphor-mimetic version of eIF4A, the authors show that phosphorylation acts to downregulate eIF4A activity, subsequently altering the efficacy of translation.

 

Heilmann M, Velanis CN, Cloix C, Smith BO, Christie JM, Jenkins GI (2016) Dimer/monomer status and in vivo function of salt-bridge mutants of the plant UV-B photoreceptor UVR8. Plant J http://dx.doi.org/10.1111/tpj.13260 Open Access

This exclusively University of Glasgow study is led by John Christie and Gareth Jenkins. Dimeric UVR8 is a UV photoreceptor that after UV-B interaction dissociates into monomers, which interact with COP1 to begin signal transduction. The UVR8 dimer develops through the formation of salt-bridges between individual UVR8 proteins. In this study the details of the dimerization are dissected, showing that several salt-bridge amino acids are necessary for the multiple functions of both the UVR8 dimer and monomer. Interestingly the authors show that UVR8 with conservative mutations of Asp96 and Asp107 to Asn96 and Asn107 are unable to form dimers yet retain wildtype responses to UV-B. This shows that monomeric UVR8 has the ability to normally initiate a signal transduction pathway and complicates our understanding of the in vivo role of the UVR8 dimer.

Fresh_Weight
Phy mutants have reduced biomass. Taken from: http://www.pnas.org/content/113/27/7667.abstract

Yang D, Seaton DD, Krahmer J, Halliday KJ (2016) Photoreceptor effects on plant biomass, resource allocation, and metabolic state. PNAS 113(27):7667-72 http://dx.doi.org/10.1073/pnas.1601309113

Karen Halliday (Edinburgh) is the corresponding author on this investigation into the broader impact of Arabidopsis phytochromes on carbon allocation and biomass production. Even though phytochrome mutants have reduced CO2 uptake they overaccumulate resources into sucrose and starch and show altered day:night growth rates. Overall this leads to reduced growth coincident with reduced expression of CELLULOSE SYNTHASE-LIKE genes. The authors demonstrate that phytochromes play a significant role in the control of biomass allocation and that they additionally differentially respond to external stresses. Evolutionarily this indicates that modification of phytochrome expression might be an important mechanism for responding to changing environments.

Kumar M, Wightman R, Atanassov I, Gupta A, Hurst CH, Hemsley PA, Turner S (2016) S-Acylation of the cellulose synthase complex is essential for its plasma membrane localization. Science. 353(6295):166-9 http://dx.doi.org/10.1126/science.aaf4009

Simon Turner (Manchester) and Piers Hemsley (James Hutton Institute, University of Dundee) lead this research which amalgamates the work from their individual labs and assesses the role of S-acylation on the activity of cellulose synthase complex (CSC). They show that core subunits of the CSC, cellulose synthase A (CESA) proteins, require s-acylation for their localisation to the plasma membrane, which is necessary for their in vivo activity. The authors estimate that a CSC might contain over 100 S-acyl groups, which could significantly alter its hydrophobicity and its interactions within the membrane environment.

CESpic
CES localisation: Taken from http://science.sciencemag.org/content/353/6295/166.full.pdf+html

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