Malcolm Bennett talks to GARNet

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Published on: December 28, 2018

Malcolm Bennett discussed a recent publication in Science entitled ‘Root branching toward water involves posttranslational modification of transcription factor ARF7‘.

GARNet Research Roundup: December 21st 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

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

30th International Conference on Arabidopsis Research

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Published on: December 5, 2018

Chinese researchers publish a lot of papers in which Arabidopsis is the primary organism of study. The 2018 MASC annual report showed that in 2017 Chinese researchers published 1318 papers, which was over double the number published by researchers in the USA.

This is the exciting backdrop for the 30th International Conference for Arabidopsis Research (ICAR) that will take place in Wuhan on June 16th-21st 2019.

The conference website went live last weekend: http://icar2019.arabidopsisresearch.org/index.html


ICAR is the largest annual conference that focuses almost exclusively on discovery-led fundamental plant research. The only time ICAR has been held in China was for ICAR2007. This remains the highest ever attended ICAR with over 1400 delegates yet took place at a time when Chinese researchers published ‘just’ 248 papers, which was a 1/3 of the number published by US researchers.

At that time China was beginning its research relationship with fundamental plant science but in 2019 it is very much the most productive nation.

There is understandable excitement for ICAR2019 as it will undoubtedly be the most highly attended ICAR and will introduce excellent Chinese research to a global conference that is conducted in English.

The organisers have kept student registration cheap at $350 for early bird registration. However be aware that on February 1st his deadline is early in the year. Abstract submission for an oral presentation is on March 1st. General registration ends on May 1st.

International attendees require a VISA to enter China so make sure you apply early to your home consulant. More information on this can be found here: http://icar2019.arabidopsisresearch.org/visa.html 

To encourage UK PhD students to attend the meeting GARNet are administering a set of 4 £500 studentships. If you are interested in these awards please contact Geraint Parry
geraint@garnetcommunity.org.uk

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