This weeks GARNet research roundup begins with a microscopy-based study led by Lorenzo Frigerio from the University of Warwick that investigates the origin of Protein Storage Vacuoles. The second paper from John Doonan at Aberystwyth University looks at how differential splicing of cyclin-dependent Kinase G1 effects the thermosensory response. Reiner van de Hoorn from Oxford leads the next paper that characterises the use of activity-based protein profiling (ABPP) to identify novel α-glycosidases in model and non-model plants. Simon McQueen-Mason from York is corresponding author of the next paper that identified a new QTL from Brachypodium that is involved in cell wall formation. The fifth paper is led by Anthony Dodd from Bristol and characterises the role of the SnRK1 complex in hypocotyl elongation whilst the penultimate manuscript from Julia Davies’s lab in Cambridge performs patch clamp analysis of dorn1 mutant plants. The final paper from Brendan Davies at the University of Leeds characterises the SMG kinase, a gene that is lacking from the Arabidopsis genome, in Physcomitrella patens.
Feeney M, Kittelmann M, Menassa R, Hawes C, Frigerio L. Protein storage vacuoles originate from remodelled pre-existing vacuoles in Arabidopsis thaliana (2018) Plant Physiol. 2018 Mar 19. pii: pp.00010.2018. doi: 10.1104/pp.18.00010 Open Access
This collaboration between the Universities of Warwick and Oxford Brookes is led by Lorenzo Frigerio and Chris Hawes. They have investigated the origin of seed Protein Storage Vacuoles (PSV) using a two-pronged approach using confocal and immunoelectron microscopy. They looked at embryo development as well as in leaf cells that have been reprogrammed for embryonic cell fate by overexpression of the LEAFY COTYLEDON2 TF. These studies indicate that PSVs are formed following the reprogramming of pre-existing embryonic vacuole (EV) rather than from de novo assembly.
Cavallari N, Nibau C, Fuchs A, Dadarou D, Barta A, Doonan JH. The Cyclin Dependent Kinase G group defines a thermo-sensitive alternative splicing circuit modulating the expression of Arabidopsis ATU2AF65A (2018) Plant J. doi: 10.1111/tpj.13914 Open Access
John Doonan (Aberystwyth University) is the corresponding author on this UK-Austrian collaboration that presents the role of the cyclin-dependent Kinase G1 (CDKG1) in thermosensing in Arabidopsis. Ambient temperature change causes altered gene expression of the spliceosome component, ATU2AF65A. Interestingly the CDKG1 gene is differentially spliced and to produces two protein isoforms that are both needed to complement the expression of ATU2AF65A across a temperature range. This alternative splicing is dependent on CDKG2 and CYCLIN L1 and is a novel control mechanism in the temperature control response.
Husaini AM, Morimoto K, Chandrasekar B, Kelly S, Kaschani F, Palmero D, Jiang J, Kaiser M, Ahrazem O, Overkleeft HS, van der Hoorn RAL (2018) Multiplex fluorescent, activity-based protein profiling identifies active α-glycosidases and other hydrolases in plants. Plant Physiol. pii: pp.00250.2018. doi: 10.1104/pp.18.00250 Open Access
Renier Van de Hoorn (University of Oxford) leads this pan-european study that uses novel cyclophellitol aziridine probes that label α-glycosidase enzymes. They identified two novel α-glycosidases in Arabidopsis as well as using the technique in non-model saffron crocus. Finally they showed that this multiplex fluorescent labelling in combination with probes for serine hydrolases and cysteine proteases can be used to identify changes in hydrolase activity in response to pathogen infection.
Whitehead C, Ostos Garrido FJ, Reymond M, Simister R, Distelfeld A, Atienza SG, Piston F, Gomez LD, McQueen-Mason SJ (2018) A glycosyl transferase family 43 protein involved in xylan biosynthesis is associated with straw digestibility in Brachypodium distachyon. New Phytol. doi: 10.1111/nph.15089 Open Access
Simon McQueen-Mason (University of York) leads this study that use QTL mapping to identify a gene in Bracypodium that is involved in cell wall architecture, which might then be a target to develop plants with improved cellulose digestibility. This glycosyl transferase family (GT) 43 protein is an orthologue of Arabidopsis IRX14, which is involved in xylan biosynthesis. When RNAi was used to reduce expression of this gene the resulting plants showed increased digestibility, indicating that this BdGT43A will be a good target for future breeding plans.
Wang L, Wilkins KA, Davies JM (2018) Arabidopsis DORN1 extracellular ATP receptor; activation of plasma membrane K(+) -and Ca(2+) -permeable conductances New Phytol. 2018 Mar 25. doi: 10.1111/nph.15111. Open Access
This letter to New Phytologist from the lab of Julia Davis (University of Cambridge) outlines some experiments to determine whether the DORN1 plasma membrane receptor is responsible for transmitting a signal from extracellular ATP (eATP). They performed patch clamp analysis on isolated protoplasts and showed that DORN1 is involved in the activation of Ca+ and K+ pumps by eATP as, in contrast to wildtype, dorn1 mutant protoplast showed no voltage changes after incubation with eATP.
Simon NML, Sawkins E, Dodd AN. Involvement of the SnRK1 subunit KIN10 in sucrose-induced hypocotyl elongation (2018) Plant Signal Behav. 27:1-9. doi: 10.1080/15592324.2018.1457913.
Anthony Dodd (University of Bristol) is the corresponding author of this follow-on study from one that previously featured on the GARNet YouTube channel. This study measures sucrose-induced hypocotyl elongation in two T-DNA mutants of the SnRK1 subunit KIN10 gene. These mutants had altered responses to sucrose leading to the hypothesis that the SnRK1 complex suppresses hypocotyl elongation in the presence of external sugar.
Lloyd JPB, Lang D, Zimmer AD, Causier B, Reski R, Davies B (2018) The loss of SMG1 causes defects in quality control pathways in Physcomitrella patens. Nucleic Acids Res. doi: 10.1093/nar/gky225 Open Access
Brendan Davis (University of Leeds) is the corresponding author on research that investigates the role of the SMG1 kinase during nonsense-mediated mRNA decay (NMD) in the moss Physcomitrella patens. This kinase plays a critical role in animals but as it is not present in Arabidopsis, its function is not well studied in plants. However moss smg mutants show expression changes in genes involved in a variety of processes indicating that NMD is a common control mechanism in moss. In addition these plants have increased susceptibility to DNA damage, which suggests that the SMG1 kinase is a key player in quality control mechanisms in plants.