Arabidopsis Research Roundup: May 27th

This weeks Arabidopsis Research Roundup sees a small number of high quality publications driven by UK-based researchers together with a couple of collaborative efforts that highlight the international aspect of research. Topics include two greatly different descriptions of how a plant responds to attack, an investigation into the intersection of vesicle and potassium transport as well as descriptions of auxin and sugar signaling.

Sarris PF, Duxbury Z, Huh SU, Ma Y, Segonzac C, Sklenar J, Derbyshire P, Cevik V, Rallapalli G, Saucet SB, Wirthmueller L, Menke FL, Sohn KH, Jones JD (2015) A Plant Immune Receptor Detects Pathogen Effectors that Target WRKY Transcription Factors. Cell 161, p1089-1100 http://dx.doi.org/10.1016/j.cell.2015.04.024

Jonathan Jones at the Sainsbury lab collaborated with his ex-PhD student Kee Hoon Sohn (now at Massey University in NZ) to produce this high profile publication in Cell. Professor Jones’s group has been in the vanguard of research into the response to bacterial pathogens and this paper adds a further layer of understanding as they show that the plant uses a bacteria’s own ‘attack mechanism’ against itself. Many bacterial effector proteins target WRKY DNA-binding protein domains in order to interfere with transcription. This work shows that the plant defence factor RRS1 also contains a WRKY domain, enabling it to ‘sense’ when the bacteria is in the cell and act as a decoy that makes the bacteria subsequently open to attack.

 

Jaouannet M, Morris JA, Hedley PE, Bos JI (2015) Characterization of Arabidopsis Transcriptional Responses to Different Aphid Species Reveals Genes that Contribute to Host Susceptibility and Non-host Resistance. PLos Pathogens 11: e1004918.

The group of Jorunn Bos at the James Hutton Institute in Dundee looked at a different aspect of the defence response whereby they investigated transcriptional responses to aphid predation on Arabidopsis. Host and non-host responses to aphids show a high degree of overlap in expression but interestingly the host response included repressive of genes involved in metabolism and oxidative response. This type of study will pave the way for the future development of aphid control strategies in crop plants and once again highlights the utility of Arabidopsis as a model system.

MyzusPersicae

Zhang B, Karnik R, Wang Y, Wallmeroth N, Blatt MR, Grefen C (2015) The Arabidopsis R-SNARE VAMP721 Interacts with KAT1 and KC1 K+ Channels to Moderate K+ Current at the Plasma Membrane Plant Cell [Epub]

Control of potassium channels is the focus of this work from Mike Blatt’s lab at the University of Glasgow. They identify a subset of SNARE proteins (that are involved in vesicle trafficing) that control K+ channels, albeit in an unconventional manner. The vesicle-associated membrane proteins 721 (VAMP721) is able to target vesicles as well as supressing the actitivty of the K+ channels KAT1 and KC. This leads to a model whereby different subsets of SNARE proteins opposingly effect K+ channel activity alongside having an effect on vesicular transport.

 

Panoli A, Martin MV, Alandete-Saez M, Simon M, Neff C, Swarup R, Bellido A, Yuan L, Pagnussat GC, Sundaresan V. (2015) Auxin Import and Local Auxin Biosynthesis Are Required for Mitotic Divisions, Cell Expansion and Cell Specification during Female Gametophyte Development in Arabidopsis thaliana. PLoS One. 10:e0126164.

The primary interest of Ranjan Swarup’s group at the University of Nottingham is in hormone signalling and root development yet he is included as a collaborator in this publication led from UC-Davies that focusses on auxin signalling during female gametophyte development. The paper shows that the YUCCA family of the auxin biosynthetic genes are asymmetrically expressed during embryo sac development and that the AUX1 and LAX1 auxin influx carriers are expressed only at both the micropylar pole of the embryo sac and in adjacent cells of the ovule. In addition aux1lax1lax2 triple mutants show numerous gametophytic developmental defects.  Given the importance of auxin in most aspects of plant development, this paper highlights the specific manner in which auxin is required for mitotic divisions, cell expansion and patterning during embryo sac development.

 

Zheng L, Shang L, Chen X, Zhang L, Xia Y, Smith C, Bevan MW, Li Y, Jing HC (2015) TANG, Encoding a Symplekin_C Domain-contained Protein, Influences Sugar Responses in Arabidopsis Plant Physiol [Epub]

Mike Bevan at the JIC is a collaborator on this Chinese driven project that investigates Arabidopsis tang1 mutants. These plants are hypersensitive to sugar amd following a classic map-based cloning approach, the TANG1 gene was found to encode a novel protein with a predicted Symplekin tight junction protein C-terminal. As TANG1 is ubquitiously expressed and has little effect on known sugar signalling pathways, the precise in vivo role of the protein remains somewhat opaque even though it is clearly an important player in the response to sugar in Arabidopsis.

Arabidopsis Research Roundup

Categories: Arabidopsis, GARNet, Global, UKPSF
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Published on: May 14, 2015

Your UK Arabidopsis Research Round-up this week contains studies that aim to define a network of lateral root formation, elucidate modes of calcium signaling, determine mechanisms of epigenetic memory and also the influence of exon-edge evolution in determining the extent of selective pressure.

Liu J, Whalley HJ, Knight MR. Combining modelling and experimental approaches to explain how calcium signatures are decoded by calmodulin-binding transcription activators (CAMTAs) to produce specific gene expression responses. New Phytologist. 2015 Apr 27. doi: 10.1111/nph.13428.

Marc Knight’s group at the University of Durham have attempted to decode the complex mechanism by which calcium controls changes in gene expression. They have developed an experimentally parameterized model that reveals calcium signals are amplified by the binding of calmodulin and calmodulin-binding transcription activators (CAMTAs). Interestingly, the model suggests that gene expression change in response to a calcium signature is defined by the previous history of that signal.

Lavenus J, Goh T, Guyomarc’h S, Hill K, Lucas M, Voß U, Kenobi K, Wilson MH, Farcot E, Hagen G, Guilfoyle TJ, Fukaki H, Laplaze L, Bennett MJ. Inference of the Arabidopsis Lateral Root Gene Regulatory Network Suggests a Bifurcation Mechanism That Defines Primordia Flanking and Central Zones. Plant Cell. 2015 May 5. pii: tpc.114.132993.

The biology of lateral root (LR) formation has been well researched over the past decade although a full robust regulatory network that controls this process has remained elusive. CPIB at the University of Nottingham, together with European collaborators have used a series of transcriptomic datasets to develop a time-delay correlation algorithm (TDCor) to infer the gene expression network (GRN) controlling LR initiation. The GRNs associated with AUXIN RESPONSE FACTOR7 and ARF5 predict a mutual inhibition and a patterning mechanism that controls flanking and central zone specification of LR primordia.

Berry S, Hartley M, Olsson TS, Dean C, Howard M Local chromatin environment of a Polycomb target gene instructs its own epigenetic inheritance. Elife. 2015 May 8;4. doi: 10.7554/eLife.07205.

Epigenetic ‘memory’ allows plant cells to retain a memory of past environmental or development events. One key regulator of this process is the Polycomb Repressive Complex2 (PRC2). Histone proteins that are modified by the PRC2 can be inherited through cell division. The groups of Mark Howard and Caroline Dean at the JIC investigated whether this inheritance directs long term memory in a cis or trans manner. Two copies of the Arabidopsis FLC gene, which is a target for PRC2, were monitored in the same plant. Interestingly they reveal that one FLC copy could be silenced but the other remained active, providing evidence that epigenetic memory, at least of FLC, is stored in trans but not in cis.

Bush SJ, Kover PX, Urrutia AO. Lineage-specific sequence evolution and exon edge conservation partially explain the relationship of evolutionary rate and expression level in A. thaliana. Mol Ecol. 2015 Apr 30. doi: 10.1111/mec.13221.

Alongside genetic changes in response to phenotypic adaptation, the elements of a genes DNA structure can also affect evolutionary rates. In Arabidopsis the ‘edge’ of exons, which flank introns and contain splice enhancers are known to have a higher degree of evolutionary conservation compared to coding regions. Dr Arazi Urrutia and collaborators from the University of Bath assessed selective pressure (measured by dN/dS) and showed that exon edge conservation partially explains the relationship between rates of protein evolution and expression level. Without any consideration of exon-edge conservation can potentially increase the number of genes designated as being under adaptive selection. Therefore the authors conclude that exon-edge conversation should be an important consideration when assessing overall dN/dS ratios.

Work for GARNet!

Categories: GARNet
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Published on: March 5, 2015

As we have mentioned on our main website, we are searching for a new GARNet Coordinator. Until now, the job has been advertised for internal Cardiff University applications only, but as of today, anyone is eligible to apply. Would you like to work for GARNet? You can find the job advertisement here: Research Associate, GARNet Coordinator.

What does a GARNet Coordinator do?

Lots of things! The GARNet Coordinator is responsible for managing the day-to-day running of the network – you can find a full job specification on the Cardiff website, but practically, the job includes things like:

  • Maintaining the GARNet website, mailing list, Twitter account and blog;
  • Organising regular meetings with our Committee, including meeting room bookings, catering and logistics, taking minutes and ensuring actions from the last meeting are completed;
  • Identifying opportunities for workshops and events that will benefit the plant science community, and then organising those events – recent past examples include the GARNet Conference, Software Carpentry workshops at Liverpool and Warwick, and an iPlant workshop. You’ll need to find sponsorship, book event space and hotel rooms, organise transport and catering, prepare delegate information packs, and so on;
  • Staying abreast of what’s currently happening in Arabidopsis and basic plant science research, and networking and liaising with members of the plant science community by attending national and international conferences such as ICAR, SEB or UKPSF;
  • Writing – we have written a number of papers published in peer reviewed journals, as well as meeting reports, contributions to consultations, guest blog posts and articles, our Arabidopsis Research Round-up, and the twice-yearly GARNish newsletter;
  • Planning and developing grant applications for resources or projects identified by the plant science community as being of value – we recently secured renewed funding for GARNet itself, and we were heavily involved with putting together the application for iPlant UK.
The GARNet Coordinator needs to be a plant scientist who is well organised, a good writer, communicator and networker. You will, on occasion, need to travel nationally and internationally, and good computer skills are a must – experience with website management, blog platforms and creative publishing software such as Adobe InDesign and Photoshop are ideal.
If you’d like any more information about the GARNet Coordinator vacancy, please feel free to submit informal enquiries to Ruth Bastow.
The closing date for applications is 19 March 2015.

Data Mining with iPlant: Published

Categories: GARNet
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Published on: October 20, 2014

Data mining with iPlant

We have a new paper published! Lisa is first author on the report from last year’s Data Mining with iPlant workshop, published last week in the Journal of Experimental Botany.

As noted in the abstract, the paper ‘provides an overview of the workshop, and highlights the power of the iPlant environment for lowering barriers to using complex bioinformatics resources, furthering discoveries in plant science research and providing a platform for education and outreach programmes.’

The full reference for the paper is: Martin L, Cook C, Matasci N, Williams J and Bastow R (2014) Data Mining with iPlant: A meeting report from the 2013 GARNet workshop ‘Data Mining with iPlant’, Journal of Experimental Botany, DOI: 10.1093/jxb/eru402

You can view the paper via this toll-free link.

Don’t forget, all the tutorials from the workshop are available for anyone to use on the iPlant Wiki pages.

GARNet 2014 presentations available online

As you’ll already know, we held our GARNet 2014 conference, Arabidopsis: The Ongoing Green Revolution, at the University of Bristol on the 9th and 10th September. If you didn’t know, you can read Charis’ report on it by clicking here to go to the main GARNet website, or here to see some photos!

Some of the researchers who spoke at our conference have kindly agreed to share their GARNet 2014 presentations with you online – please click the links in the programme below to view or download a PDF copy of the speaker’s slides.

 

Programme

Session 1: Physiology & Productivity

Session 2: Genome Biology

Session 3: Natural Variation

Session 4: Systems and Synthetic Biology

Arabidopsis Research Round-up

Apologies there hasn’t been an Arabidopsis Research Round-up for a few weeks, I’ve been on annual leave getting married! Here’s a catch up of the newest Arabidopsis research papers from the UK community over the last month, including one from a GARNet committee member, and one from a former GARNet PI.

 

  • Schatlowski N, Wolff P, Santos-González J, Schoft V, Siretskiy A, Scott R, Tamaru H and Köhler C. Hypomethylated pollen bypasses the interploidy hybridization barrier in Arabidopsis. The Plant Cell, 1 September 2014. DOI: 10.1105/tpc.114.130120.

Rod Scott from the University of Bath was involved on this Plant Cell paper. With Swedish, Austrian and Swiss colleagues, it was identified that, through the suppression of expressed imprinted genes, hypomethylation can occur in pollen that alters the epigenetic control of the ‘interploidy hybridization barrier’. Based on these findings, the researchers here present a novel method for the generation of viable triploid Arabidopsis plants, which could have significant impact for plant breeding.

 

  • Chew YH, Wenden B, Flis A, et alMultiscale digital Arabidopsis predicts individual organ and whole-organism growth. Proceedings of the National Academy of Sciences of the United States of America, 2 September 2014. DOI: 10.1073/pnas.1410238111. [Open Access]

You can tell former GARNet PI Andrew Millar from the University of Edinburgh led this paper – it’s all about linking the Arabidopsis research community! Quantitative modeling is undeniably an important tool in modern predictive biology, but understanding plants at a molecular level doesn’t necessarily help us to ‘bridge the genotype to phenotype gap’ and predict how molecular changes affect the whole organism, or vice versa. Linking together several models across multiple scales, Millar and colleagues here present a validated multiscale model of Arabidopsis rosette growth, enabling prediction of how genetic regulation and biochemical dynamics may affect organ and whole-plant growth.

 

  • Chao D-Y, Baraniecka P, Danku J, Koprivova A, Lahner B, Luo H, Yakubova E, Dilkes BP, Kopriva S and Salt DE. Variation in sulfur and selenium accumulation is controlled by naturally occurring isoforms of the key sulfur assimilation enzyme APR2 across the Arabidopsis thaliana species range. Plant Physiology, 18 September 2014. DOI: 10.1104/pp.114.247825. [Open Access]

GARNet committee member and ‘Mr Ionomics’ David Salt, from the University of Aberdeen, was the lead on this new paper in Plant Physiology, working with colleagues from the John Innes Centre, Purdue, Cologne and Shanghai. This study used linkage mapping in synthetic F2 populations to investigate the natural variation in total leaf sulphur and selenium levels across a wide range of Arabidopsis thaliana accessions. Though the significance is not yet understood, it was found that the catalytic capacity of APR2, an enzyme important in allowing the accumulation of sulphur and selenium in leaves, varied by four orders of magnitude.

 

  • Fujikura U, Elsaesser L, Breuninger H, Sanchez-Rodriguez C, Ivakov A, Laux T, Findlay K, Persson S and Lenhard M. Atkinesin-13A modulates cell wall synthesis and cell expansion in Arabidopsis thaliana via the THESEUS1 pathway. PLOS Genetics, 18 September 2014. DOI: 10.1104/pp.114.247825. [Open Access]

For plants to grow they need to not only proliferate their cells, but expand the size of the cells too. Since plant cells are encased in a rigid cell wall, the cell wall structure must be temporarily loosened to allow expansion and the deposition of additional cell wall materials. Working with a German-led team and colleagues in Australia, Kim Findlay from the John Innes Centre contributed to this paper, which discusses the roles of AtKINESIN-13-A and its homologue AtKINESIN-13B in limiting cell expansion and size in Arabidopsis thaliana.

 

  • Johansson H, Jones HJ, Foreman J, Hemsted JR, Stewart K, Grima R and Halliday KJ. Arabidopsis cell expansion is controlled by a photothermal switch.Nature Communications, 26 September 2014. DOI: 10.1038/ncomms5848. [Open Access]

A second appearance in today’s Round-up for the University of Edinburgh’s Karen Halliday, and another paper discussing cell expansion. This time, this Nature Communications paper explores the finding that phytochrome B-controlled growth in the Arabidopsis hypocotyl is strictly regulated by temperature: a shift in temperature induces a dramatic reversal of response from inhibition to promotion of hypocotyl elongation by light.

GARNet 2014: In pictures

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Published on: September 16, 2014

GARNet 2014, Arabidopsis: The Ongoing Green Revolution, is over! We had a great two days of discussions, networking, speciality cupcakes, and of course excellent talks from researchers at all career stages, from ‘one of the fathers of Arabidopsis research’ to a few of the UK’s brightest young PhD students.

There is a report on the conference on our website, and also a Storify of Tweets. Thank you to everyone who attended and contributed to discussions in situ and on Twitter – we’re delighted to work with such a supportive, enthusiastic community!

Here are a some pictures from the event – they’re mostly of the speakers (Maarten Koorneef, Andrew Millar, Cyril Zipfel, Kerry Franklin, and Miriam Gifford) and panel sessions, with a few pictures of the networking sessions towards the end.
garnet2014 1

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GARNet goes global with the Global Plant Council

If you follow me on Twitter (@GARNetweets) then you’ll know that I’ve been out of the office quite a lot recently, attending a variety of conferences.

Charis has already blogged about our trip to Manchester for the Society of Experimental Biology conference a couple of weeks ago, but I’ve also been helping out our colleague Ruth Bastow at some conferences further afield.

The Global Plant CouncilAs well as being GARNet’s part-time co-ordinator, Ruth is also Executive Director for the Global Plant Council (GPC) – a coalition of global crop and plant science societies that aims to connect the wealth of knowledge and expertise from around the world to help find solutions to global plant science challenges.

The GPC is focusing on three priority initiatives: firstly the creation of a Digital Seed Bank, which aims to capture and exploit the wealth of diversity in crop collections around the globe. The Digital Seed Bank is part of larger project; the Diversity Seek Initiative (DivSeek), whose mission is to unlock the potential of crop diversity stored in genebanks around the world and make it available to all so that it can enhance the productivity, sustainability and resilience of crops and agricultural systems.

This is an ambitious project and will need to tackle problems such as how to tag or assign a DOI to genetic resources, just as you can to a journal paper. If this can be done, scientists will be able to trace published work or data back to a single seed, accession or group, and know where they can find and access that germplasm to cross-reference and compare data. A grand aspiration, but aim high and you never know what you might achieve!

GPC is also working to join up global research and policy in the areas of biofortification and stress resilience. There are many scientists across the globe working on the improvement of crops, whether by traditional or marker assisted breeding, or using GM or synthetic biology technologies – wouldn’t it be great if we could facilitate better global collaborations on these projects?

The Convention Centre Dublin, or The Coke Can, to its friends!
The Convention Centre Dublin, or The Coke Can, to its friends!

The GPC is made up of (at present) 28 member organisations, including some big players such as the American Society of Plant Biologists (ASPB), the European Plant Science Organisation (EPSO), the Society for Experimental Biology (SEB) and our own UK Plant Sciences Federation (UKPSF).

As members of these societies, many researchers are also members of the GPC by default – whether they realise it or not! To help spread the word to these organisation’s members, I’ve been helping Ruth to man (woman?) an exhibition booth.

So first we flew off to Dublin and attended EPSO’s Plant Biology Europe 2014 conference (23–26th June). This was held at the Convention Centre Dublin in Ireland (known locally, I’m reliably informed, as the ‘Coke Can’!).

Delegates at the EPSO conference came from all over the world
Delegates at the EPSO conference came from all over the world

Our booth was well attended and generated lots of interest from not just European plant scientists as you might expect, but also the global community. Rather than just collecting email addresses in a list, we collected business cards, or got people to fill in a GPC card, and pinned them to a world map so we could see exactly how ‘global’ the GPC’s reach is – I was surprised to meet delegates in Dublin from as far afield as Africa, Australia and New Zealand!

As well as working on the booth, we also had the opportunity to hear some great talks, including a public evening lecture given by Charles Godfray from Oxford University. Charles put a population biologist’s twist on ‘The Challenge of Global Food Security”; lamenting our ‘Malthusian pessimism’ about the need to feed 10 billion people by 2050 and resistance to technologies that might allow us to do this, Godfray said that failure is not an option – “If we fail to have food security, everything will fail,” he said. A sobering thought!

Portland is known for being a bit on the "alternative" side
Portland is known for being a bit on the “alternative” side

After Dublin, and a week in Manchester at SEB, I was back on the plane again; this time heading to Portland in Oregon in the US’s pacific northwest. After a few days’ holiday exploring this very cool ‘hipster’ city and sampling the infamous Voodoo Donuts, Ruth and I set up our GPC booth, this time at the Oregon Convention Centre for the ASPB Plant Biology 2014 conference.

As you can see from the map we generated this time, it was a different demographic who visited the booth; mostly researchers from the US, Canada and western Europe, although we did speak to a few people from Asia and Latin America too. The GPC’s giveaway pens went down a treat here and I came home with only one left!

Our Global Plant Council map at the ASPB conference
Our Global Plant Council map at the ASPB conference

Again, I found some time between exhibit sessions to attend a few talks, and was particularly impressed by journalist/food writer Nathanael Johnson, winner of the ASPB award for Leadership in Science. He spoke about the challenge of communicating science to the public, arguing “facts are not enough”. The big issues in science, he said, are simply too big and too complex for people to grasp, so instead they will grasp at small pieces of information they can understand – and this is often how things like the anti-vaccination movement, or anti-GM campaigners get started. Building trust between scientists, industry and the public is of huge importance, because simply giving people piles of ‘evidence’ has no impact a) if people do not understand it, and b) if there is an assumption that it is inaccurate or they are being misled.

Ruth in the Booth
Ruth in the Booth

So now I’m back in the GARNet office (though the weather here in Coventry is just as hot as it was in Portland!) but only for a week. This weekend the whole GARNet team is off to Vancouver for the International Conference on Arabidopsis Research (ICAR), so stay tuned for more blog posts and tweets from Canada!

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