This week’s GARNet research roundup again features papers on a variety of topics. First is work from the University of Leeds that investigates the physical properties of callose:cellulose hydrogels and the implication for cell wall formation. Second is work from the University of York that assesses the role of the HSP90.2 protein in control of the circadian clock. The third paper features GARNet committee member Sarah McKim and looks at the genetic control of petal number whilst the next paper from the Universities of Warwick and Glasgow includes a proteomic analysis of different types of secretory vesicles.
The next two papers look at different aspects of hormone signaling. Firstly Alistair Hetherington from the University of Bristol is a co-author on a study that looks at the role of the BIG protein whilst Simon Turner’s lab in Manchester investigates the role of ABA in xylem fibre formation.
The penultimate paper includes Lindsey Turnbull from the University of Oxford and looks at the stability of epialleles across 5 generations of selection. Finally is a paper that includes researchers from TSL in Norwich who have contributed to a phosphoproteomic screen to identify phosphorylated amino acids that influence the defence response.
Abou-Saleh R, Hernandez-Gomez M, Amsbury S, Paniagua C, Bourdon M, Miyashima S, Helariutta Y, Fuller M, Budtova T, Connell SD, Ries ME, Benitez-Alfonso Y (2018) Interactions between callose and cellulose revealed through the analysis of biopolymer mixtures. Nature Communications DOI: 10.1038/s41467-018-06820-y
Radwa Abou-Saleh is lead author on this work from Yoselin Benitez-Alfonso’s lab at the University of Leeds. (1,3)-β-glucans such as callose play an important role in plant development yet their physical properties are largely unknown. This study analyses a set of callose:cellulose hydrogel mixtures as a proxy for different cell wall conditions. They show that callose:cellulose hydrogels are more elastic than those composed of only cellulose, providing evidence that the interactions between cellulose and callose are important for the structural features of cell walls.
Davis AM, Ronald J, Ma Z, Wilkinson AJ, Philippou K, Shindo T, Queitsch C, Davis SJ (2018) HSP90 Contributes To Entrainment of the Arabidopsis Circadian Clock via the Morning Loop. Genetics. doi: 10.1534/genetics.118.301586
Amanda Davies is the first author on this study from Seth Davies’ lab at the University of York in which they assess the role of the molecular chaperone HSP90.2 on function of the circadian clock. The show hsp90.2-3 mutant plants have a lengthened circadian period with a specific defect in the morning. This data allows the authors to better understand the pathway through which HSP90.2 functions to entrain the circadian clock.
Monniaux M, Pieper B, McKim SM, Routier-Kierzkowska AL, Kierzkowski D, Smith RS, Hay A. The role of APETALA1 in petal number robustness. Elife. doi: 10.7554/eLife.39399
GARNet committee member Sarah McKim is a co-author on this paper, that is led by Marie Monniaux, which includes research from her time at the University of Oxford. This work from the Hay lab in Cologne compares petal number in Arabidopsis thaliana, in which the number is invariant, and Cardamine hirsute, in which it varies. They show that petal number robustness can be attributed to the activity of the APETALA1 (AP1) floral regulator and that AP1 masks the activity of several genes in Arabidopsis but not in Cardamine.
Waghmare S, Lileikyte E, Karnik RA, Goodman JK, Blatt MR, Jones AME (2018) SNAREs SYNTAXIN OF PLANTS 121 (SYP121) and SYP122 mediate the secretion of distinct cargo subsets . Plant Physiol. doi: 10.1104/pp.18.00832
This collaboration between the Universities of Glasgow and Warwick is led by Sakharam Waghmare, who works with Mike Blatt in Glasgow. This study uses proteomic approaches to characterise the secretory cargos within vesicles decorated with either of the SNARE proteins SYNTAXIN OF PLANTS 121 (SYP121) or SYP122. Genetic analysis suggests that SYP121 and SYP122 have redundant functions but this new research is able to identify cargo proteins that are either contained within both types of vesicle or that are specific to one or the other.
Zhang RX, Ge S, He J, Li S, Hao Y, Du H, Liu Z, Cheng R, Feng YQ, Xiong L, Li C, Hetherington AM, Liang YK (2018) BIG regulates stomatal immunity and jasmonate production in Arabidopsis. New Phytol. doi: 10.1111/nph.15568
Alistair Hetherington is a co-author on this China-based study led by Ruo‐Xi Zhang from Wuhan. This work adds to some recent interest in the BIG protein; in this study showing that it is involved in the interaction between JA and ethylene signaling during stress responses. In a complex set of interactions they show that the BIG protein differently alters opposing arms of the JA signaling pathway providing additional evidence that this protein is a key regulator of plant hormone signaling, albeit by a set of as yet unknown mechanisms.
Campbell L, Etchells JP, Cooper M, Kumar M, Turner SR. An essential role for Abscisic acid in the regulation of xylem fibre differentiation. Development. doi: 10.1242/dev.161992
This work from Simon Turner’s lab at the University of Manchester is led by Liam Campbell and identifies a novel role for ABA in the formation of xylem fibres during secondary thickening of the Arabidopsis hypocotyl. The action of ABA doesn’t alter the xylem:phloem ratio but rather the activity focuses on the formation of fibres within the already defined xylem tissue.
Schmid MW, Heichinger C, Coman Schmid D, Guthörl D, Gagliardini V, Bruggmann R, Aluri S, Aquino C, Schmid B, Turnbull LA, Grossniklaus U (2018) Contribution of epigenetic variation to adaptation in Arabidopsis. Nat Commun. doi: 10.1038/s41467-018-06932-5
Lindsey Turnbull (University of Oxford) is a co-author on this paper from Ueli Grossniklaus’ group in Zurich. Marc Schmid is lead author of the study that investigates the inheritance of Arabidopsis epialleles over 5 generations during conditions of simulated selection. The authors show that variations in methylation state are subject to selection and do indeed contribute to adaptive responses
Kadota Y, Liebrand TWH, Goto Y, Sklenar J, Derbyshire P, Menke FLH, Torres MA, Molina A, Zipfel C, Coaker G, Shirasu K (2018) Quantitative phosphoproteomic analysis reveals common regulatory mechanisms between effector- and PAMP-triggered immunity in plants. New Phytol. doi: 10.1111/nph.15523
Members of Cyril Zipfel’s group at The Sainsbury lab in Norwich are co-authors on this paper led by Yasuhiro Kadota from the RIKEN in Yokohama. They use a phosphoproteomic screen to identify a set of newly identified phosphorylation sites on membrane-associated proteins involved in effector-triggered immunity (ETI). Some of these phosphosites overlap with those known to be important for pathogen-associated molecular pattern (PAMP)-triggered immunity (PTI), indicating a convergence of signaling control of both these pathways to certain key residues.