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 7th 2019

This edition of the GARNet research roundup begins with a study into the genetic basis of fertility in barley led by Sarah McKim from Dundee. Second is a study from Oxford and Leicester that characterizes the proteolytic control of chloroplast import. The third paper from Levi Yant’s group at JIC and Nottingham that attempts to discover the influence of polyploidism on population genomic effects whilst the fourth paper from Juliet Coates’ lab in Birmingham uses the growth of Arabidopsis to assess the potential of algal biomass as a biofertiliser. The next two papers include co-authors from Oxford and Warwick respectively and investigate different factors that control seed viability in Arabidopsis and Brassica oleracea. The final paper includes Seth Davies from York as a co-author on a study that looks at control of the circadian clock in field-grown Arabidopsis.


Zwirek M, Waugh R, McKim SM (2019) Interaction between row-type genes in barley controls meristem determinacy and reveals novel routes to improved grain. New Phytol. doi: 10.1111/nph.15548

Open Access

Current GARNet committee members Sarah McKim is the leader of this study in which first author is Monica Zwirek. They investigate the mechanism through which the barley VRS genes contribute to spikelet fertility. They undercover the epistatic relationship between five VRS genes that explains how they contribute to controlling fertility of lateral spikelets. Importantly they demonstrate that various vrs mutant combinations improve fertility in a variety of ways, information that will be useful during the generation of new varieties of barley.

https://nph.onlinelibrary.wiley.com/doi/full/10.1111/nph.15548

Ling Q, Broad W, Trösch R, Töpel M, Demiral Sert T, Lymperopoulos P, Baldwin A, Jarvis RP (2019) Ubiquitin-dependent chloroplast-associated protein degradation in plants. Science. doi: 10.1126/science.aav4467

Qihua Ling and William Broad are the first authors on this study from the Universities of Oxford and Leicester. They investigate the role of proteolysis in the functional control of chloroplast-envelope translocases, which are required for the transport of proteins from nucleus-encoded genes into the chloroplast. They identify two newly characterised proteins that function in the same pathway as the known ubiquitin E3 ligase SP1. These novel proteins, SP2 and CDC48, are both required for the movement of ubiquitinated proteins from the chloroplast outer envelope membrane (OEM) into the cytosol, where they are degraded by the proteolytic machinery. This process of chloroplast-associated protein degradation (CHLORAD) maintains tight control of the activity of OEM proteins and is essential for organelle function.

http://science.sciencemag.org/content/363/6429/eaav4467.long

Monnahan P, Kolář F, Baduel P, Sailer C, Koch J, Horvath R, Laenen B, Schmickl R, Paajanen P, Šrámková G, Bohutínská M, Arnold B, Weisman CM, Marhold K, Slotte T, Bomblies K, Yant L (2019) Pervasive population genomic consequences of genome duplication in Arabidopsis arenosa. Nat Ecol Evol. doi: 10.1038/s41559-019-0807-4.

Patrick Monnahan at the John Innes Centre is first author on this study from the Yant lab that has recently moved to the University of Nottingham. In this collaboration with colleagues in the US, Austria, Sweden, the Czech Republic and Slovakia, they have performed large scale sequencing on 39 populations of Arabidopsis arenosa. These plants have differing levels of ploidy and they are attempting to understand how ploidy effects population genomics. They demonstrate that the ploidy effects are subtle but significant and that masking of deleterious mutations, faster substitution rates and interploidy introgression will likely impact the evolution of populations where polyploidy is common.


Ghaderiardakani F, Collas E, Damiano DK, Tagg K, Graham NS, Coates J (2019) Effects of green seaweed extract on Arabidopsis early development suggest roles for hormone signalling in plant responses to algal fertilisers. Sci Rep. doi: 10.1038/s41598-018-38093-2

Open Access

This work from the Coates lab at the University of Birmingham is led by Fatemeh Ghaderiardakani and looked into the potential of algal extracts as biofertiliser. They showed that at >0.1%, extracts taken from the common green seaweed Ulva intestinalis inhibit Arabidopsis seed germination and root elongation. At lower concentrations primary root elongation was promoted albeit with a complete loss of lateral root formation. Elemental analysis allows the authors to suggest that this effect was mediated via a novel mechanism involving aluminium. Overall the authors caution against the use of algal biofertilisers due to potential unforeseen negative effects on plant growth.


Viñegra de la Torre N, Kaschani F, Kaiser M, van der Hoorn RAL, Soppe WJJ, Misas Villamil JC (2019) Dynamic hydrolase labelling as a marker for seed quality in Arabidopsis seeds. Biochem J. doi: 10.1042/BCJ20180911.

GARNet Committee member Renier van der Hoorn is a co-author on this German-led study that investigates how the activity of seed-localised proteases can affect Arabidopsis seed germination. This study has clear real-world application regarding the storage of economically important seed stocks. They show that vacuolar processing enzymes (VPEs) become more active during aging whilst the activity of serine hydrolases declines alongside seed quality. This information has allowed the authors to develop protease-activity-based markers that will provide information about seed quality.


Schausberger C, Roach T, Stöggl WM, Arc E, Finch-Savage WE, Kranner I (2019) Abscisic acid-determined seed vigour differences do not influence redox regulation during ageing. Biochem J. doi: 10.1042/BCJ20180903

William Finch-Savage from the University of Warwick is a co-author on this Austrian-led study that looks at the effect of aging on the quality of Brassica oleracea seeds stored at two oxygen concentrations. Higher O2 causes a more rapid decrease in seed quality through aging yet in contrast aging did not alter the impact of the hormone ABA on seed viability. This study enables the authors to uncover two mechanisms that control seed quality that appear to act through different mechanisms.


Rubin MJ, Brock MT, Davis SJ, Weinig C (2019) QTL Underlying Circadian Clock Parameters Under Seasonally Variable Field Settings in Arabidopsis thaliana G3 (Bethesda). doi: 10.1534/g3.118.200770

Open Access

Seth Davies from the University of York is a co-author on this study led by Matthew Rubin from the University of Wyoming. They looked at the growth of Arabidopsis thaliana recombinant inbred lines grown in field conditions and found an extremely nuanced relationship regarding how QTLs that influence the circadian clock respond to environmental conditions. For example the authors showed that plant growth in June, July and September is controlled by different QTL architecture, demonstrating the complex regulation of the circadian clock in these field growth plants.

GARNet Research Roundup: February 14th 2019

This GARNet research Roundup includes a broad range of topics and contributing institutions. First is a study from TSL that investigates the molecular basis of Arabidopsis and Brassica responses to white rust disease. Second is work from Warwick that uses Arabidopsis as a tool to test genes involved in the evolution of Flax domestication.

The third paper is work from Cambridge that models the response of the circadian oscillator to nicotinamide whilst the fourth paper is a study from the University of Dundee that compares differential gene expression software in the analysis of RNAseq data from a complex organism. The penultimate paper includes a co-author from the University of Oxford and has generated an extended phylogeny of the Brassicaceae family. The final paper compares the growth and metabolite profiles of Arabidopsis and Eutrema salsugineum following drought stress.


Cevik V, Boutrot F, Apel W, Robert-Seilaniantz A, Furzer OJ, Redkar A, Castel B, Kover PX, Prince DC, Holub EB, Jones JDG (2019) Transgressive segregation reveals mechanisms of Arabidopsis immunity to Brassica-infecting races of white rust (Albugo candida). Proc Natl Acad Sci U S A. doi: 10.1073/pnas.1812911116

Open Access

https://www.pnas.org/content/116/7/2767.long

Volkan Cevik is the lead author on this international collaboration that is led by Jonathan Jones at the Sainsbury Lab, Norwich. They have taken advantage of Arabidopsis resistance to white rust (Albugo candida) and used the Multiparent Advanced Generation InterCross (MAGIC) lines to identity the genes responsible for this resistance. This is important as related crop species Brassica juncea and Brassica oleracea are sensitive to this economically important pathogen. They identified a range of nucleotide-binding, leucine-rich repeat (NLR)-encoding genes that were involved in resistance to the pathogen.


Gutaker RM, Zaidem M, Fu YB, Diederichsen A, Smith O, Ware R, Allaby RG (2019) Flax latitudinal adaptation at LuTFL1 altered architecture and promoted fiber production. Sci Rep. doi: 10.1038/s41598-018-37086-5

Open Access

https://www.nature.com/articles/s41598-018-37086-5

Rafal Gutaker is the lead author on this collaborative study between the University of Warwick and colleagues in Germany, Canada and Denmark, which investigated the route of domestication of the cultivated crop Flax. At northern european latitudes flax evolved to become a fibre crop rather than an oil crop by stem expansion and reduction of seed size. The authors investigated the role in this adaptation of PEBP family genes in the flax genome, LuTFL1 and LuTFL2. LuTFL1 was heterologously expressed in Arabidopsis, demonstrating that it is able to perform roles in flowering time and plant architecture. This research highlights the importance of Arabidopsis as a tool for testing the function of genes from less-easily transformed organisms.


Mombaerts L, Carignano A, Robertson FR, Hearn TJ, Junyang J, Hayden D, Rutterford Z, Hotta CT, Hubbard KE, Maria MRC, Yuan Y, Hannah MA, Goncalves J, Webb AAR (2019) Dynamical differential expression (DyDE) reveals the period control mechanisms of the Arabidopsis circadian oscillator. PLoS Comput Biol. doi: 10.1371/journal.pcbi.1006674

Open Access

Laurents Mombarts is the first author in this collaboration between the departments of Plant science and Engineering at the University of Cambridge that looked at the mechanistic effect on nicotinamide on the timing of the circadian oscillation. They developed a systematic and practical modeling framework for the gene regulatory circuits that respond to nicotinamide. They initially developed a mathematical model and then experimentally confirmed their predictions to uncover a role for blue light signalling in this response. Overall their approach could be adapted to predict mechanisms of drug action in other complex biological systems.


Froussios K, Schurch NJ, Mackinnon K, Gierlinski M, Duc C, Simpson GG, Barton GJ (2019) How well do RNA-Seq differential gene expression tools perform in a complex eukaryote? A case study in A. thaliana. Bioinformatics. doi: 10.1093/bioinformatics/btz089

Open Access

Gordon Simpson and colleagues at the University of Dundee collaborate with researchers in Clermont-Ferrand with Kimon Froussios as first author. They use Arabidopsis as a model to test a set of Differential Gene Expression (DGE) tools for the effective analysis of RNAseq data generated with three or fewer biological replicates. They tested nine widely used DGE tools and ultimately recommend the use of tools that are based on the negative binomial distribution.

https://journals.plos.org/ploscompbiol/article?id=10.1371/journal.pcbi.1006674

Nikolov LA, Shushkov P, Nevado B, Gan X, Al-Shehbaz IA, Filatov D, Bailey CD, Tsiantis M (2019) Resolving the backbone of the Brassicaceae phylogeny for investigating trait diversity. New Phytol. doi: 10.1111/nph.15732.

https://nph.onlinelibrary.wiley.com/doi/abs/10.1111/nph.15732

This German, US and UK collaboration is led by Lachezar Nikolov and includes Dmitry Filatov from the University of Oxford as a co-author. They generated a phylogeny of the Brassicaceae, the family that contains Arabidopsis and a number of economically important crops. They used a mixture of fresh tissue and herbarium samples to perform the analysis on almost 80 species; enabling the resolution of new relationships between family members. This work represents an important tool for phylogenetic and comparative studies to maximise future outputs.


Pinheiro C, Dickinson E, Marriott A, Ribeiro IC, Pintó-Marijuan M, António C, Zarrouk O, Chaves MM, Dodd IC, Munné-Bosch S, Thomas-Oates J, Wilson J (2019) Distinctive phytohormonal and metabolic profiles of Arabidopsis thaliana and Eutrema salsugineum under similar soil drying. Planta. doi: 10.1007/s00425-019-03095-5

This collaboration between the UK and Portugal is led by Carla Pinheiro and the corresponding author is Julie Wilson from the University of York. Eutrema salsugineum is a stress-tolerance relative of Arabidopsis and in this study the authors have compared the response of these plants following growth on drying soils. Whereas stomatal sensitivity was similar in both species there were significant differences in metabolite profiles and water usage following drought stress. This analysis allowed the authors to conclude that Arabidopsis is indeed a good model for analysis of responses to commonly encountered levels of drought stress.

GARNet Research Roundup: November 22nd 2018

This GARNet Research Roundup begins with two studies from the University of Sheffield. First is research from Jurriaan Ton’s lab that looks at the interaction between CO2 concentration, the soil microbiome and plant growth. The second paper from Matt Davey and Peter Quick looks at the effect of cold acclimation on freezing tolerance in Arabidpsis lyrata.

The third study includes authors from Dundee and Durham and also looks at an impact of altered CO2 concentrations, in this case on nitrogen assimilation.

The next paper looks at the role of a GA signaling module on endosperm expansion during seed germination and includes authors from Nottingham and Birmingham.

The fifth paper includes Richard Morris at the JIC as a co-author and looks at the relationship between calcium signaling and changes in cellular pH. The penultimate study features co-authors from Warwick and Exeter in work that looks at the role of 3′-O-β-D-ribofuranosyladenosine during plant immunity. Finally is a paper that includes Steve Long from Lancaster and characterises the rubisco-chaperone BSD2.


Williams A, Pétriacq P, Beerling DJ, Cotton TEA, Ton J (2018) Impacts of Atmospheric CO(2) and Soil Nutritional Value on Plant Responses to Rhizosphere Colonization by Soil Bacteria. Front Plant Sci. doi: 10.3389/fpls.2018.01493

https://www.frontiersin.org/articles/10.3389/fpls.2018.01493/full

Open Access

Alex Williams is the lead author of this paper and works with Jurriaan Ton at the University of Sheffield. The impact of the soil rhizosphere on plant growth is emerging as an important growth determinant. In this paper the authors assess the role of altered [CO2] and soil carbon (C) and nitrogen (N) concentration in the colonisation of Arabidopsis roots by two different bacteria. Firstly they showed that altered [CO2] did not change the growth dynamics of the saprophytic bacteria Pseudomonas putida KT2440 and was independent of soil C or N. In contrast growth of the rhizobacterial strain Pseudomonas simiae WCS417 was sensitive to both changing [CO2] and soil composition. These results show the importance of the interaction between atmospheric CO2 and soil nutritional status during plant interactions with soil bacteria.


Davey MP, Palmer BG, Armitage E, Vergeer P, Kunin WE, Woodward FI, Quick WP (2018) Natural variation in tolerance to sub-zero temperatures among populations of Arabidopsis lyrata ssp. petraea. BMC Plant Biol. doi: 10.1186/s12870-018-1513-0

Open Access

Matthew Davey, now working in Cambridge, collaborated with Peter Quick at the University of Sheffield on this research that looks at the tolerance of Arabidopsis lyrata to freezing. They showed that populations from locations with colder winter climates were better able to survive subzero temperatures, particular when they have been acclimated at near zero for longer periods. This demonstrates that the adaptation of plants to cold temperatures allows them to better survive freezing, although surprisingly this effect is lessened when this acclimation period does not occur.


Andrews M, Condron LM, Kemp PD, Topping JF, Lindsey K, Hodge S, Raven JA (2018) Effects of elevated atmospheric [CO2] on nitrogen (N) assimilation and growth of C3 vascular plants will be similar regardless of N-form assimilated. J Exp Bot. doi: 10.1093/jxb/ery371

This UK-New Zealand collaboration is led by Mitchell Andrews and looks at the effect of elevated [CO2] on the nitrogen (N) assimilation when the plant is exposed to a variety of different N-sources. They show that in C3 plants the overall N assimilated will be the same whether the plant is under ammonium (NH4+) nutrition or under nitrate (NO3-) nutrition. These results are contrary to previous results that suggest elevated [CO2] reduces plant growth under NO3- nutrition.


Sánchez-Montesino R, Bouza-Morcillo L, Marquez J, Ghita M, Duran-Nebreda S, Gómez L, Holdsworth MJ, Bassel G, Oñate-Sánchez L (2018) A regulatory module controlling GA-mediated endosperm cell expansion is critical for seed germination in Arabidopsis. Mol Plant. doi: 10.1016/j.molp.2018.10.009 

https://www.sciencedirect.com/science/article/pii/S1674205218303356

Open Access

This Spanish-led project includes authors from the Universites of Nottingham and Birmingham. They look at the influence of a GA signalling module on endosperm cell separation, which is essential for Arabidopsis seed germination. They show the NAC transcription factors NAC25 and NAC1L control expression of the EXPANSION2 gene and that the GA signalling component RGL2 has a controlling influence by repressing this activity.


Behera S, Xu Z, Luoni L, Bonza C, Doccula FG, DeMichelis MI, Morris RJ, Schwarzländer M, Costa A (2018) Cellular Ca2+ signals generate defined pH signatures in plants. Plant Cell. doi: 10.1105/tpc.18.00655

Open Access

Richard Morris (John Innes Centre) is a co-author on this Italian-led study that investigates the role of Calcium ions in cell signalling. They use a set of genetically-encoded fluorescent sensors to visualise a link between Ca2+ signaling and changes in pH. If this link is maintained across all cell types it might represent an extra layer of complexity and control of cellular signal transduction.


Drenichev MS, Bennett M, Novikov RA, Mansfield J, Smirnoff N, Grant M, Mikhailov S (2018) A role for 3′-O-β-D-ribofuranosyladenosine in altering plant immunity. Phytochemistry. doi: 10.1016/j.phytochem.2018.10.016

https://www.sciencedirect.com/science/article/pii/S0031942218301997?via%3Dihub

This Russian-led study includes UK-based researchers Mark Bennett, Murray Grant, Nick Smirnoff and John Mansfield as co-authors. They show that the natural disaccharide nucleoside, 3′-O-β-D-ribofuranosyladenosine accumulated in plants infected with the bacterial pathogen P. syringae. Perhaps surprisingly the application of this nucleoside to the plant doesn’t effect bacterial multiplication, indicating that adds a significant metabolic burden to plants already battling new infections.


Conlan B, Birch R, Kelso C, Holland S, De Souza AP, Long SP, Beck JL, Whitney SM (2018) BSD2 is a Rubisco specific assembly chaperone, forms intermediary hetero-oligomeric complexes and is non-limiting to growth in tobacco. Plant Cell Environ. doi: 10.1111/pce.13473

Steve Long is a Professor at Lancaster Environment Centre and is a co-author on this Australia-led study that characterizes the role of the Rubisco chaperone BSD2 during Rubisco biogenesis. These results suggest this is the sole role of BSD2 and its activity is non-limiting to tobacco growth.

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: 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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