GARNet committee member Sarah McKim talks to GARNet about a recent paper published in New Phytologist entitled ‘Interaction between row-type genes in barley controls meristem determinacy and reveals novel routes to improved grain‘.
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This edition of the GARNet research roundup begins with a study from the John Innes Centre that investigates the role of auxin in the control of fruit development in Capsella.
Auxin is also a central focus of the next paper that is from SLCU, in which the authors characterise the role of different types of auxin transport during shoot development. The third paper, also from Cambridge, identifies a new function for members of the DUF579 enzyme family. The final paper from Cambridge reports on an outstanding citizen science project that looks at how different temperature and light conditions influence the growth of spring onions.
The next paper is from the University of Glasgow and investigates the role of the SNARE protein complex during vesicle transport in Arabidopsis.
The final two papers include authors from the University of Nottingham. Firstly Anthony Bishopp leads research that defines determinants of vascular patterning across plant species. Finally Don Grierson is a co-author on work that has identified novel signaling components involved in the response to hypoxia in Persimmon and Arabidopsis.
Dong Y, Jantzen F, Stacey N, Łangowski Ł, Moubayidin L, Šimura J, Ljung K, Østergaard L (2019) Regulatory Diversification of INDEHISCENT in the Capsella Genus Directs Variation in Fruit Morphology. Curr Biol. doi: 10.1016/j.cub.2019.01.057
Open Access
This research from Lars Ostergaard’s lab in the John Innes Centre is led by Yang Dong. The work is primarily conducted in Capsella and investigates the role of the INDEHISCENT (IND) protein in this plant, which has fruits that are morphologically distinct from those in Arabidopsis. Expression of CrIND controls fruit shape by influencing auxin biosynthesis leading to auxin accumulation in specific maxima that are localised to the fruit valves.
van Rongen M, Bennett T, Ticchiarelli F, Leyser O (2019) Connective
auxin transport contributes to strigolactone-mediated shoot branching
control independent of the transcription factor BRC1. PLoS Genet. doi: 10.1371/journal.pgen.1008023
Open Access
Martin Van Rongen is the lead author on this research performed under the supervision of Ottoline Leyser at the Sainsbury Lab, Cambridge University. They investigate the hormonal signals that underpin the remarkable plasticity of shoot patterning, focusing on a genetic analysis of connective auxin transport (CAT), which moves the hormone across the stem (in contrast to up-down polar transport). Using multiple pin mutant plants, they show CAT is important in the regulation of strigolactone-mediated shoot branching. However shoot branching controlled by the BRANCHED1 transcription factor is reliant on the ABCB19 auxin export protein and is not significantly influenced by the activity of PIN proteins. Martin van Rongen discusses this paper on the GARNet YouTube channel.
Temple, H, Mortimer, JC, Tryfona, T, et al (2019) Two members of the DUF579 family are responsible for arabinogalactan methylation in Arabidopsis. Plant Direct. https://doi.org/10.1002/pld
Open Access
Henry Temple works with Paul Dupree at the University of Cambridge and leads this study that identifies a novel activity of two DUF579 enzymes in the methylation of glucuronic acid within highly glycosylated arabinogalactan proteins (AGPs). This differs from all other previously characterized DUF579 members that have been previously shown to methylate glucuronic acid within the cell wall component xylan.
Brestovitsky, A, Ezer, D (2019) A mass participatory experiment provides a rich temporal profile of temperature response in spring onions. Plant Direct. 2019; 3: 1– 11. https://doi.org/10.1002/pld3.126
Open Access
This citizen science project led by Anna Brestovitsky and Daphne Ezer was performed in collaboration with the BBC Terrific Scientific program. In this study primary school students from across the UK recorded the growth of spring onions over a two-week period, which was then cross-referenced with detailed hourly meteorological data. This allowed the authors to discern the effect of minute temperature and light changes on plant growth and perhaps more importantly demonstrated that even the youngest researchers, when involved a well-designed citizen science project, can yield very useful data.
Zhang B, Karnik RA, Alvim JC, Donald NA, Blatt MR (2019) Dual Sites for SEC11 on the SNARE SYP121 Implicate a Binding Exchange during Secretory Traffic. Plant Physiol. doi: 10.1104/pp.18.01315
Open Access
Ben Zhang and Rucha Karnik are first authors on this paper that continues Mike Blatt‘s lab’s study of SNARE proteins, which are involved in vesicle trafficking. This study defines a new amino acid motif within SNARE SYP121 that is needed for the binding of the SEC11 protein but is not involved in binding plasma membrane K+ channels. This motif is essential for assembly of the entire SNARE complex yet does not influence the interaction of SYP121 with the uptake of K+ ions.
Mellor N, Vaughan-Hirsch J, Kümpers BMC, Help-Rinta-Rahko H, Miyashima S, Mähönen AP, Campilho A, King JR, Bishopp A (2019) A core mechanism for specifying root vascular patterning can replicate the anatomical variation seen in diverse plant species. Development. doi: 10.1242/dev.172411
Open Access
Nathan Mellor is first author on this work led by the lab of Anthony Bishopp at the University of Nottingham. The primary accomplishment of this work is in the development of a mathematical model that is able to predict the role of auxin in the specification of vascular patterning during embryonic development. This model has been tested through experimental interrogation of both transgenic Arabidopsis plants and in a range of other species with different vascular development patterns. Importantly they show that a heterologous auxin input might not be as critical in vascular development when compared to growth patterns that arise from spatial constraints. The authors show that this model has broad relevance to define early vascular patterning across plant species.
Zhu QG, Gong Z, Huang J, Grierson D, Chen KS, Yin XR (2019) High-CO2/hypoxia-responsive transcription factors DkERF24 and DkWRKY1 interact and activate DkPDC2 promoter. Plant Physiol. doi: 10.1104/pp.18.01552
Open Access
Don Greirson is a co-author on this Chinese-led study that identifies a set of transcription factors from Persimmon ((Diospyros kaki). These TFs are involved in responses to high CO2 and the authors show that their Arabidopsis orthologs play a similar role. The authors introduce a new response module that may be important during this key environmental response.
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.
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.
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.
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