GARNet Research Roundup: March 7th 2019

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


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

Open Access

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

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

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

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

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

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

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


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

Open Access

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


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

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


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

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


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

Open Access

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

GARNet Research Roundup: February 14th 2019

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

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


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

Open Access

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

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


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

Open Access

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

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


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

Open Access

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


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

Open Access

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

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

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

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

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


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

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

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