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GARNet Research Roundup: February 14th 2019

Categories: Cambridge University, Global, James Hutton Institute, Uncategorized, University of Dundee, University of Oxford, University of York

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Published on: February 14, 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.

DiversifyPlantSci

by Geraint

Categories: Global, Uncategorized

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Published on: February 5, 2019

The North American Arabidopsis Steering Committee (NAASC) is committed to promoting a global plant sciences community that reflects the true diversity of all its members. To further this mission, the NAASC Diversity and Inclusion Task Force has created the DiversifyPlantSci online resource, a list of plant biologists from under-represented
groups to reference for speakers, reviewers, and participants for career or mentorship opportunities.

We hope to increase diversity and inclusion by making it easy to expand invitations past one’s personal networks.

To add yourself or others to the list:
https://goo.gl/forms/s461eDrbKzoK1JzD2

To access the list:
https://tinyurl.com/DiversifyPlantSci

Please forward this invitation to your networks to spread as widely as possible!

Warmly,

Elizabeth Haswell, Washington University in St. Louis, ehaswell@wustl.edu

Joanna Friesner, Executive Director: North American Arabidopsis Steering Committee, UC Davis, jdfriesner@ucdavis.edu

GARNet Research Roundup: January 31st 2019

by Geraint

Categories: Cambridge University, Global, SLCU, Uncategorized, University of Birmingham

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Published on: January 31, 2019

This edition of the GARNet research roundup has an initial focus on the shoot apical meristem. Firstly a study from the University of Birmingham performs network analysis to define the connections that control the global organisation of this tissue.

Second is the first of a group of papers involving authors from the Sainsbury Lab, Cambridge University and the University of Cambridge. Henrik Jönsson and Henrik Ahl contribute to a study that refines our understanding about the role of auxin in leaf dorsoventral patterning. Next from SLCU are two papers published in collaboration with the University of Helsinki that identify a set of novel regulators of cambial development.

The final SLCU paper from James Locke’s group attempts to tackle the challenging topic of ‘noise’ in biological systems. The final paper from the University of Cambridge investigate factors involved in karrikin signaling.

The penultimate paper characterises the LINC complex in monocots and includes authors from Oxford Brookes University whilst the final paper is from the University of York and performs a structural analysis of a key enzyme involved in the potential phytoremediation of TNT.

Jackson MDB, Duran-Nebreda S, Kierzkowski D, Strauss S, Xu H, Landrein B, Hamant O, Smith RS, Johnston IG, Bassel GW (2019) Global Topological Order Emerges through Local Mechanical Control of Cell Divisions in the Arabidopsis Shoot Apical Meristem. Cell Syst. doi: 10.1016/j.cels.2018.12.009

Open Access

George Bassel is corresponding author of this paper led by Matthew Jackson at the University of Birmingham. They use live 3D imaging and computational analysis to identify a network of cellular connections in the shoot apical meristem. They show that locally generated cell division rules lead to emergence of global tissue organisation, which facilitates cellular communication. In addition they show that global cellular organization requires the activity of the KATANIN protein.

Bhatia N, Åhl H, Jönsson H, Heisler MG (2019) Quantitative analysis of auxin sensing in leaf primordia argues against proposed role in regulating leaf dorsoventrality. Elife. doi: 10.7554/eLife.39298

Open Access

Henrik Jönsson and Henrik Ahl at SLCU are co-authors on this study led by Neha Bhatia at the University of Sydney. They use data gained from analysis of the R2D2 auxin sensor to argue against the current hypothesis stating that asymmetric auxin distribution is necessary to define the dorso-ventral polarity of the Arabidopsis leaf. They repeat previous experiments using the DII auxin sensor and through additional analysis using an auxin insensitive version of the sensor (mDII), provide results that contrast to previously published data.

https://elifesciences.org/articles/39298

Miyashima S, Roszak P, Sevilem I, Toyokura K, Blob B, Heo JO, Mellor N, Help-Rinta-Rahko H, Otero S, Smet W, Boekschoten M, Hooiveld G, Hashimoto K, Smetana O, Siligato R, Wallner ES, Mähönen AP, Kondo Y, Melnyk CW, Greb T, Nakajima K, Sozzani R, Bishopp A, De Rybel B, Helariutta Y (2019). Mobile PEAR transcription factors integrate positional cues to prime cambial growth. Nature doi: 10.1038/s41586-018-0839-y

Smetana O, Mäkilä R, Lyu M, Amiryousefi A, Sánchez Rodríguez F, Wu MF, Solé-Gil A, Leal Gavarrón M, Siligato R, Miyashima S, Roszak P, Blomster T, Reed JW, Broholm S, Mähönen AP (2019). High levels of auxin signalling define the stem-cell organizer of the vascular cambium. Nature. doi: 10.1038/s41586-018-0837-0

These back-to-back manuscripts include Pawel Roszak from the SLCU as an author in both papers. The corresponding author for the first paper, which is a true global collaboration, is Yrjo Helariutta who holds research positions at both SLCU and the University of Helsinki. These papers introduce a new signalling module of transcriptional factors that control radial growth initiated in procambial cells. In root protophloem cells cytokinin induces the expression of a newly characterised set of PEAR transcription factors, which form a short-range concentration gradient and initiate radial growth. To maintain tight developmental control of this program PEAR protein activity is antagonised by HD-ZIP III proteins, whose expression domain is controlled by the activity of auxin and a set of mobile miRNAs. The identification of this signalling module increases our understanding about the factors that control the growth of woody tissues and therefore has enormous translational significance.

Cortijo S, Aydin Z, Ahnert S, Locke JC (2019) Widespread inter-individual gene expression variability in Arabidopsis thaliana Mol Syst Biol. doi: 10.15252/msb.20188591

Open Access

Sandra Cortijo is the lead author of this paper and works with James Locke at SLCU. They have attempted to address the fundamental question of noise within biological outputs through analysis of gene expression from a set of identical Arabidopsis plants grown in identical conditions. They identify hundreds of genes that show variable expression between these plants, with different gene sets changing throughout the diurnal cycle. They further define this variability by identifying gene length, the number of transcription factors regulating the genes and the chromatin environment as contributory factors to explain why this variation occurs.

Swarbreck SM, Guerringue Y, Matthus E, Jamieson FJC, Davies JM (2019) Impairment in karrikin but not strigolactone sensing enhances root skewing in Arabidopsis thaliana. Plant J. doi: 10.1111/tpj.14233

Stéphanie Swarbreck is the first author of this work from Julia Davies’ lab at the University of Cambridge. They show that perception of karrikins (smoke-derived butenolides) through the interaction of the KAI2 hydrolase and MAX2 F-box protein occurs independent of strigolactone-sensing mechanism of the MAX2-D14 hydrolase interaction. Karrikins cause a root skewing phenotype so the authors use this output to identify that previously characterised SMAX1 (SUPPRESSOR OF MAX2-1)/SMXL2 and SMXL6,7,8 (SUPPRESSOR OF MAX2-1-LIKE) proteins are targets of degradation by the KAI2/MAX2 complex. Overall they show that KAI2/MAX2 limits root skewing but is not involved in the role KAI2 plays in gravi- or mechano-sensing. These results are indicative of a set of KAI2 specific ligands that control root skewing yet candidate proteins for these roles remain to be identified.

Gumber HK, McKenna JF, Estrada AL, Tolmie AF, Graumann K, Bass HW (2019) Identification and characterization of genes encoding the nuclear envelope LINC complex in the monocot species Zea mays. J Cell Sci. doi: 10.1242/jcs.221390

This paper is led by Hank Bass and Hardeep Gumber from Florida State University and includes Joe McKenna, Andrea Tolmie and Katja Graumann at Oxford Brookes as co-authors. They use phylogenetic and microscopic analysis to identify and characterise components of the nuclear-envelope spanning LINC (Linker of Nucleoskeleton to Cytoskeleton) complex in Zea mays. They identify a set of monocot-specific members of the LINC complex, which will allow an increased understanding about the functional linkages between the cytoplasm, nuclear envelope, nucleoplasm and chromatin.

Hank Bass discusses this paper on the GARNet YouTube channel. Hank and Katja are members of the EU COST action entitled ‘Impact of Nuclear Domains On Gene Expression and Plant Traits (INDEPTH).

Tzafestas K, Ahmad L, Dani MP, Grogan G, Rylott EL, Bruce NC (2018) Structure-Guided Mechanisms Behind the Metabolism of 2,4,6-Trinitrotoluene by Glutathione Transferases U25 and U24 That Lead to Alternate Product Distribution Front Plant Sci. doi: 10.3389/fpls.2018.01846

Open Access

Kyriakos Tzafestas is the first author on this paper from the University of York led by Neil Bruce. They perform a structural analysis of the Arabidopsis tau class glutathione transferase, GSTU25, which is involved in the phytoremediation of 2,4,6-trinitrotoluene (TNT). This analysis identified of a key set of amino acids involved in a precise part of its enzymatic activity, which can in turn be transferred to the related, but enzymatically-inert GSTU24. These findings will aid in the development of increasingly efficient strategies for plant-based remediation of environmental TNT.

Hank Bass talks to GARNet

by Geraint

Categories: Global, INDEPTH, Uncategorized

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Published on: January 23, 2019

Hank describes a recent paper published in the Journal of Cell Science entitled ‘Identification and characterization of genes encoding the nuclear envelope LINC complex in the monocot species Zea mays’. This paper also includes fellow INDEPTH member Katja Graumann from Oxford Brookes University.

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White Paper from the International Arabidopsis Informatics Consortium

by Geraint

Categories: Global, Uncategorized

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Published on: January 18, 2019

The International Arabidopsis Informatics Consortium (IAIC) has existed since 2010 to facilitate the maintenance, development and evolution of informatics tools that primarily support Arabidopsis researchers.

They have recently published a White paper on the future of Arabidopsis bioinformatics resources.

As we all know the first published plant genome was that of Arabidopsis thaliana in 2000 and since that time Arabidopsis has been used extensively around the globe as the primary plant experimental organism.

At the present time the use of Arabidopsis as a model organism has plateaued in most Western countries but is still on the rise in China and, as reported in the 2018 Multinational Arabidopsis Steering Committee (MASC) Annual Report, there remain more Arabidopsis-focused papers published than those than focus on any other single plant, although rice is catching up fast!!

Therefore with such a large number of researchers requiring effective bioinformatic tools to help their experimental planning and analysis it is essential that these tools are maintained and expanded.

The current situation sees TAIR and Araport existing as two complimentary resources. Active since 1999, TAIR is the older resource and now emphasizes high quality functional annotation. Araport was established in 2014 following a community recommendation from the last IAIC White paper and now focuses on the computational aggregation of diverse resources. TAIR is funded through an innovative subscription model that has maintained the resource over the past 5 years, Araport was funded by NSF and but unfortunately since publication of the White Paper it has emerged that NSF’s currently will not renew this funding.

Both these resources are clearly US-based as a holdover from the early uptake of Arabidopsis research in that country. As mentioned above TAIR received subscriptions from across the world so it remains to be seen how Araport might be funded as there is a clear community need for this resource.

In order to plan for the next phase of bioinformatics support for Arabidopsis and wider plant science researchers, the IAIC met in St Louis in May 2018 and the White Paper resulted from that meeting. One common theme that emerged from the meeting was the importance of metadata standards to facilitate comparable reuse of any deposited data. In addition it became clear that a robust upfront plan for gene ID assignment was critical for the future facile comparison of data from different experiments, across ecotypes and even between species.

Overall the workshop discussions resulted the formulation of the following recommendations:

Integration of data and tools: Identifying a need for a system for standardiSing and integrating data that is sustainable and not overly dependent on a few individuals. This can be achieved by development of a PlantHub or Arabidopsis Super-Portal as well as overseeing a managed expansion of fully integrated analysis tools.

Data formats and standards: This is extremely challenging but there should be community agreement on ontologies, standards and formats, their usage, and enforcement across all types of data. This would allow linkage with independently developed annotation and datasets and thus would require an authority to maintain a gold standard.

Tool development: With more data generation comes the requirement for new ways of browsing genomes that can be integrated with other overlapping ‘omic databases and then compared across genomes and networks. This type of higher level software development will need collaboration with the larger IT community, especially if the end goal is a set of simple GUIs (graphical user interfaces) that encompass more complex underlying information.

As ever the primary challenge lies in obtaining the funding and manpower to meet these recommendations. This should be a global effort given the international uptake of the resources that has been initially developed using US-based funding sources. The TAIR-type funding model is sufficient to maintain their excellent service but development of new tools requires a significant new commitment.

Over the short term the recommendations have resulted in the set up of an Arabidopsis Community Hub hosted by TAIR. This contains a list of software tools that will be of broad interest to plant scientists. They are happy to include additional appropriate links to other well-used tools. This site links to the GARNet Resources page that also contains a similar set of resources, arranged over a broader set of headings.

Please visit the TAIR Arabidopsis Community site and watch this space for updates on how the Arabidopsis bioinformatics community will evolve over the coming years.

GARNet Research Roundup: Jan 11th 2019

by Geraint

Categories: Bristol University, Cardiff University, epigenetics, Global, John Innes Centre, Nottingham University, Oxford University, Plos One, RHUL, Sainsbury Lab, Uncategorized, University of Birmingham, University of Bristol, University of Oxford, University of Sheffield

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Published on: January 11, 2019

The inaugural GARNet Research Roundup of 2019 firstly includes a paper from the University of Sheffield that has identified new pericentromeric epigenetic loci that affect the pathogen response. Secondly is a collaboration between researchers in Birmingham, Nottingham and Oxford that has identified a new mode of regulation of the VRN2 protein. Next are two papers from Jonathan Jones’ lab at The Sainsbury Laboratory in Norwich that firstly provides a toolkit for gene editing in Arabidopsis and secondly characterise the role of the NRG1 gene in the defense response. The penultimate paper is from Paul Devlin’s lab at RHUL and investigates the role of the circadian clock in the control of leaf overtopping whilst the final paper is a meeting report from a recent GARNet workshop on gene editing.

Furci L, Jain R, Stassen J, Berkowitz O, Whelan J, Roquis D, Baillet V, Colot V, Johannes F, Ton J (2019) Identification and characterisation of hypomethylated DNA loci controlling quantitative resistance in Arabidopsis. Elife. doi: 10.7554/eLife.40655.

Open Access

Leonardo Furci and Ritushree Jain are the lead authors on this study conducted at the University of Sheffield. The authors used a population of epigenetic recombinant inbred lines (epiRILs) to screen for resistance to the oomycete pathogen Hyaloperonospora arabidopsidis. These lines each share genetic information but have varied epigenetic changes. This analysis enabled the identification of plants with hypomethylated pericentromeric regions that were primed to better respond to the presence of this pathogen. The authors discuss the mechanism through which this might affect the defence response albeit without altering other aspects of plant growth.

https://elifesciences.org/articles/40655

Gibbs DJ, Tedds HM, Labandera AM, Bailey M, White MD, Hartman S, Sprigg C, Mogg SL, Osborne R, Dambire C, Boeckx T, Paling Z, Voesenek LACJ, Flashman E, Holdsworth MJ (2018) Oxygen-dependent proteolysis regulates the stability of angiosperm polycomb repressive complex 2 subunit VERNALIZATION 2. Nat Commun. doi: 10.1038/s41467-018-07875-7

Open Access

This collaboration between the Universities of Birmingham, Nottingham, Oxford and colleagues in Utrecht is led by Daniel Gibbs. They demonstrate that the amount of VRN2 protein, which is a member of the Polycomb Repressive Complex2, is controlled by the N-end rule pathway and that this regulation responses to both cold and hypoxia stress. Whilst the VRN2 gene is expressed throughout the plant, the N-end rule degradation pathway ensures that the protein is restricted to meristematic regions until the plant senses the appropriate abiotic stress. Classically VRN2 has been linked to the regulation of flowering time by altering gene expression at the FLC locus so this study introduces new complexity into this process through the involvement of the N-end rule pathway. More information on this linkage will undoubtedly follow over the coming years.

https://www.nature.com/articles/s41467-018-07875-7

Daniel kindly discusses this paper on the GARNet YouTube channel.

Castel B, Tomlinson L, Locci F, Yang Y, Jones JDG (2019) Optimization of T-DNA architecture for Cas9-mediated mutagenesis in Arabidopsis. PLoS One. doi: 10.1371/journal.pone.0204778

Open Access

Baptiste Castel is lead author of this work conducted at the Sainsbury Laboratory, Norwich in Jonathan Jones’ group. They have conducted a detailed analysis of the factors that contribute to successful gene editing by CRISPR-Cas9, specifically in Arabidopsis. This includes assessing the efficacy of different promotor sequences, guideRNAs, versions of Cas9 enzyme and associated regulatory sequences in the editing of a specific locus. Given that researchers are finding that different plants have different requirements when it comes to successful gene editing, this type of analysis will be invaluable for anyone who plans to conduct a gene editing experiment in Arabidopsis.

https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0204778

Castel B, Ngou PM, Cevik V, Redkar A, Kim DS, Yang Y, Ding P, Jones JDG (2018) Diverse NLR immune receptors activate defence via the RPW8-NLR NRG1. New Phytol. doi: 10.1111/nph.15659

In this second paper led by Baptiste Castel, they used the techniques outlined in the paper above to generate a set of CRISPR mutants deficient in NRG1, which is a RPW8-NLR resistance (R) gene. These nrg1 mutants have compromised signalling in all tested downstream TIR-NLR resistance genes. In addition the authors demonstrate that this signalling is needed for resistance to oomycete but not bacterial infection. Therefore this study reveals some significant details regarding the components of the disease response that are influenced by the activity of NRG1.

Woodley Of Menie MA, Pawlik P, Webb MT, Bruce KD, Devlin PF (2018) Circadian leaf movements facilitate overtopping of neighbors. Prog Biophys Mol Biol. doi: 10.1016/j.pbiomolbio.2018.12.012

This work is led by Michael Woodley Of Menie from Paul Devlin’s lab at Royal Holloway College and investigates the role of circadian leaf movements during shade avoidance and overtopping. Arabidopsis plants were grow in a grid system that meant leaves would interact with their neighbours and the authors show that plants with a normal circadian rhythm gained an advantage over those adapted to a longer period in which they were grown. This overtopping was additive to the advantage gained through shade avoidance and overall this paper shows that maintainance of clock-aligned leaf movements are beneficial to growth.

Parry G, Harrison CJ (2019) GARNet gene editing workshop. New Phytol. doi: 10.1111/nph.15573

Open Access

GARNet advisory committee member Jill Harrison and GARNet coordinator Geraint Parry are authors on this meeting report resulting from a GARNet organised workshop on gene editing that took place in March 2018 at the University of Bristol. Coincidentally part of the paper discusses the work that was presented at the meeting by Baptiste Castel, which is published in the paper described above.

GARNet Research Roundup: December 21st 2018

by Geraint

Categories: Arabidopsis, Cambridge University, Durham University, Edinburgh University, Global, John Innes Centre, Nottingham University, SLCU, Uncategorized

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Published on: December 20, 2018

This bumper Festive Edition of the GARNet Research Roundup begins with two papers that have Beatriz Orosa-Puente as lead author following her work on SUMOylation with Ari Sadanandom at Durham. These papers looks at the role of SUMOylation in either auxin-mediated hydropatterning or in the defence response. Malcolm Bennett at Nottingham is a co-author on both papers and provided an audio description of the auxin-focused paper on the GARNet YouTube channel.

The next three papers are from the University of Edinburgh, the first that defines the role of HECT ubiquitin ligases in the defence response, the second that conducts a proteomic analysis of the GIGANTEA-interactome and the third that introduces a set of new tools for inducible gene expression in Arabidopsis roots.

The sixth and seventh papers feature authors from the John Innes Centre. Martin Howard and Caroline Dean are corresponding authors on a multi-scale analysis of the factors that control FLC expression whilst Myriam Charpentier’s lab has contributed to an investigation about LINC complexes in Medicago.

David Salt and Levi Yant from Nottingham lead the next paper that provides an analysis of the genetic determinants of adaptation to different salt conditions.

The final three papers are from Cambridge. Firstly Ian Henderson is the corresponding author on work that looks at crossover rates in specific disease resistance loci. Second is work from the Paszkowski lab at SLCU that introduces a new method for the analysis of active retrotransposons in crop plants whilst finally James Locke, also at SLCU, uses the method of distributed delays to simplify the complexity of biological network models.

Orosa-Puente B, Leftley N, von Wangenheim D, Banda J, Srivastava AK, Hill K, Truskina J, Bhosale R, Morris E, Srivastava M, Kümpers B, Goh T, Fukaki H, Vermeer J, Vernoux T, Dinneny JR, French AP, Bishopp A, Sadanandom A , Bennett MJ (2018) Roots branch towarss water by post-translational modification of the transcription factor ARF7 Science DOI: 10.1126/science.aau3956

Orosa B, Yates G, Verma V, Srivastava AK, Srivastava M, Campanaro A, De Vega D, Fernandes A, Zhang C, Lee J, Bennett MJ, Sadanandom A (2018) SUMO conjugation to the pattern recognition receptor FLS2 triggers intracellular signalling in plant innate immunity. Nat Commun. doi: 10.1038/s41467-018-07696-8 Open Access

http://science.sciencemag.org/content/362/6421/1407

Beatriz Orosa-Puente is the lead author on two publications that have arisen from a collaboration between the labs of Ari Sadanandom at Durham and Malcolm Bennett at Nottingham. In the first paper Beatriz is co-first author with Nicola Leftley and Daniel von Wangenheim in research that links the auxin response, SUMOylation and the search for water. They reveal a novel mechanism for controlling the auxin response in which SUMOylation regulates the interaction between the ARF7 and IAA3 proteins. In turn this controls asymmetric expression of genes downstream of ARF7 and determines how different parts of the root response to the presence or absence of water.

The second paper continues with the Sadanandom lab’s focus on SUMOylation, in this case during control of the defence response. They show that SUMO is conjugated to the FLAGELLIN-SENSITIVE 2 (FLS2) receptor that senses bacterial flagellin. This releases downstream cytoplasmic effectors and enhances the immune response. The authors show that there is additional complexity to this system by also showing that flagellin induces degradation of the deSUMOylating enzyme Desi3a, thus allowing the plant to make a stronger immune response.

Furniss JJ, Grey H, Wang Z, Nomoto M, Jackson L, Tada Y, Spoel SH (2018) Proteasome-associated HECT-type ubiquitin ligase activity is required for plant immunity. PLoS Pathog. doi: 10.1371/journal.ppat.1007447 Open Access

James Furniss is the lead author on this paper from the lab of current GARNet Chairman Steven Spoel at the University of Edinburgh. They show that a family of HECT domain-containing ubiquitin protein ligases (UPLs) are involved in defence responses mediated by the hormone salicylic acid (SA). Upl3 mutants show reprogramming of the entire SA transcriptional response and they are unable to establish immunity against a hemi-biotrophic pathogen, demonstrating their key role in this important process.

https://febs.onlinelibrary.wiley.com/doi/abs/10.1002/1873-3468.13311

Krahmer J, Goralogia GS, Kubota A, Zardilis A, Johnson RS, Song YH, MacCoss MJ, LeBihan T, Halliday KJ, Imaizumi T, Millar AJ (2018) Time-resolved Interaction Proteomics of the GIGANTEA Protein Under Diurnal Cycles in Arabidopsis. FEBS Lett. doi: 10.1002/1873-3468.13311 Open Access

This paper is a collaboration between researchers in Edinburgh and Seattle for which Johanna Krahmer is lead author. They used a proteomic approach to identify proteins that interacted with a tagged-version of the key circadian regulator GIGANTEA. They successfully identified the novel transcription factor CYCLING DOF FACTOR (CDF)6. CDF6 was confirmed as interacting with GI and playing a role in the control of flowering. The time series of proteomic data produced in this study is available for use by any other interested researcher.

http://proteomecentral.proteomexchange.org/cgi/GetDataset?ID=PXD006859

Machin FQ, Beckers M, Tian X, Fairnie A, Cheng T, Scheible WR, Doerner P (2018) Inducible reporter/driver lines for the Arabidopsis root with intrinsic reporting of activity state. Plant Journal. doi: 10.1111/tpj.14192

Frank Qasim Machin is the lead author on this Technical Advance from Peter Doerner’s lab at the University of Edinburgh. They have developed a Gateway-based system for tightly controlled inducible expression across all the major cell types of the Arabidopsis roots. They have fully characterised reference driver lines that can be adapted for specific experimental requirements and hope that this contributes towards enhancing reproducibility of qualitative and quantitative analyses.

https://www.sciencedirect.com/science/article/pii/S2405471218304368?via%3Dihub

Antoniou-Kourounioti RL, Hepworth J, Heckmann A, Duncan S, Qüesta J, Rosa S, Säll T, Holm S, Dean C, Howard M (2018) Temperature Sensing Is Distributed throughout the Regulatory Network that Controls FLC Epigenetic Silencing in Vernalization. Cell Syst. doi: 10.1016/j.cels.2018.10.011 Open Access

This work results from the successful collaboration between Caroline Dean and Martin Howard at the John Innes Centre and includes Rea Antoniou-Kourounioti and Jo Hepworth as co-first authors. They attempt to understand how the upregulation of VERNALIZATION INSENSITIVE3 (VIN3) and silencing of FLOWERING LOCUS C (FLC) is controlled during fluctuating temperatures over month-long time scales. They develop a mathematical model that integrates information from hour, day and month-long datasets to show that temperature is sensed across the entire regulatory network and not focussed on specific nodes. This allows a final effect to only be realised once all parts of the network have been appropriately changed. This model with matches new field data and therefore represents a predictive tool for the effects of climate change on plant growth.

Newman-Griffis AH, Del Cerro P, Charpentier M, Meier I (2018) Medicago LINC complexes function in nuclear morphology, nuclear movement, and root nodule symbiosis Plant Physiol. http://www.plantphysiol.org/content/early/2018/12/10/pp.18.01111 Open Access
Pablo del Cerro and Myriam Charpentier at the John Innes Centre are co-authors on this paper from Iris Meier’s lab at The Ohio State University. They identify and characterise the Linker of Nucleoskeleton and Cytoskeleton (LINC) family of nucleus-membrane-associated proteins. They show that, as in Arabidopsis, these proteins are required for nucleus movement in the root tip cells of Medicago truncatula and that they are an important contributor to nodulation. Both Iris and Myriam are members of the INDEPTH consortium that includes researchers who study this broad area of plant cell biology.

https://www.pnas.org/content/early/2018/12/11/1816964115.long

Busoms S, Paajanen P, Marburger S, Bray S, Huang XY, Poschenrieder C, Yant L, Salt DE (2018) Fluctuating selection on migrant adaptive sodium transporter alleles in coastal Arabidopsis thaliana. Proc Natl Acad Sci U S A. doi: 10.1073/pnas.1816964115 Open Access

This UK-Sino-Spanish collaboration is led by David Salt and Levi Yant at the University of Nottingham. Silvia Busoms is the first author on the study that investigates the genetics of adaptive salt tolerance in a cohort of 77 individuals grown across a salinity gradient in a coastal region of Catalonia. By integrating their data with the 1135 genomes project they are able to trace the ancestry of these populations and define that growth in high salt conditions is associated with increased expression of the high-affinity K⁺ transporter (HKT1;1). This demonstrates that this gene plays a key role in the adaptation to salt stress.

Serra H, Choi K, Zhao X, Blackwell AR, Kim J, Henderson IR. Interhomolog polymorphism shapes meiotic crossover within the Arabidopsis RAC1 and RPP13 disease resistance genes (2018) PLoS Genet. doi: 10.1371/journal.pgen.1007843 Open Access

This UK-Korean collaboration is led by the Heidi Serra and Ian Henderson at the University of Cambridge. They mapped the meiotic crossover hotspots that are located within the RAC1 and RPP13 disease resistance genes in Arabidopsis. They assessed these locations in plants with altered recombination rates and surprisingly showed that these effects have little impact at the RAC1 loci. Therefore they show that chromosome location and local chromatin environment are important for regulation of crossover activity. Overall they demonstrate that interhomolog divergence is important in shaping recombination within plant disease resistance genes and crossover hotspots.

Cho J, Benoit M, Catoni M, Drost HG, Brestovitsky A, Oosterbeek M, Paszkowski J (2018) Sensitive detection of pre-integration intermediates of long terminal repeat retrotransposons in crop plants. Nat Plants. doi: 10.1038/s41477-018-0320-9

Open Access with link: rdcu.be/bdLjy

For the second edition in succession, the GARNet research roundup features work from Jerzy Paszkowski’s lab at SLCU. In this case Jungnam Cho is lead author on work that has developed a new technique called ALE-seq (amplification of LTR of eclDNAs followed by sequencing) for analysis of transposon-rich genomes from crop plants. Through characterisation of extrachromosomal linear DNA (eclDNA), ALE-seq allows the identification of active transposons. The authors use this technique in both rice and tomato and successfully identify a set of developmentally regulated transposable elements. This paper includes details of a bioinformatic pipeline that is adapted for ALE-seq data analyses, the scripts for which are available on GitHub.

Tokuda IT, Akman OE, Locke JCW. Reducing the Complexity of Mathematical Models for the Plant Circadian Clock by Distributed Delays (2018) J Theor Biol. doi: 10.1016/j.jtbi.2018.12.014

This UK-Japanese study includes James Locke at SLCU as corresponding author. They address the challenge of integrating an increasing number of parameters into large biological network models. Their system of study is the Arabidopsis circadian clock and they use the method of distributed delays to simplify the complexity of existing models. They demonstrate this effect by updating a model that explains the regulation of the PRR9 and PRR7 genes by LHY. They use recent experimental data and revise the previous model to show that it is more accurately reproduces the LHY-induction experiments of core clock genes. As stated they show that overall use of distributed delays facilitates the optimisation and reformulation of genetic network models.

GARNet Research Roundup: December 7th 2018

by Geraint

Categories: Aberystwyth University, Global, John Innes Centre, Lancaster University, Nottingham University, Rothamsted Research, Sainsbury Lab, SLCU, University of Birmingham, University of Bristol, University of Sheffield

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Published on: December 7, 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

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