ARABIDOPSIS RESEARCH ROUNDUP: JUNE 17THARABIDOPSIS RESEARCH ROUNDUP: JUNE 17TH

17th Jun 2015

This weeks roundup features a wide range of research topics from two current members of GARNet Advisory board as well as two papers featuring work from the lab of Laszlo Bogre at Royal Holloway. The studies range from an investigation into the similarity between the barley and Arabidopsis circadian clocks, the role of MYR3R during regulation of organ growth, documenting a novel interaction of a MAPK protein and the development of new fluorescent probes for study of cysteine proteases.

 

Kusakina J, Rutterford Z, Cotter S, Martí MC, Laurie DA, Greenland AJ, Hall A, Webb AA (2015) Barley Hv CIRCADIAN CLOCK ASSOCIATED 1 and Hv PHOTOPERIOD H1 Are Circadian Regulators That Can Affect Circadian Rhythms in Arabidopsis. PLoS One. 10(6):e0127449. http://dx.doi.org/10.1371/journal.pone.0127449

This publication is the result of a multi-site collaboration between the Alex Webb at Cambridge, GARNet Advisory board member Anthony Hall at Liverpool, Andy Greenland at NIAB and David Laurie at the JIC. The focus of this study are the barley CIRCADIAN CLOCK ASSOCIATED 1 and PHOTOPERIODH1 genes, which are involved in regulation of the circadian clock. The authors investigated the circadian rhythms in barley whilst using heterologous expression in Arabidopsis to show that the barley CCA1 is functionally equivalent to AtCCA1 and that barley PHOTOPERIODH1 functions similar to AtPRR7.

 

Kobayashi K, Suzuki T, Iwata E, Nakamichi N, Suzuki T, Chen P, Ohtani M, Ishida T, Hosoya H, Müller S, Leviczky T, Pettkó-Szandtner A, Darula Z, Iwamoto A, Nomoto M, Tada Y, Higashiyama T, Demura T, Doonan JH, Hauser MT, Sugimoto K, Umeda M, Magyar Z, Bögre L, Ito M (2015) Transcriptional repression by MYB3R proteins regulates plant organ growth. EMBO J. http://dx.doi.org/10.15252/embj.201490899

GARNet advisory board member John Doonan and Royal Hollaway-based Laszlo Bogre are collaborators on this multi-nation publication that looked at the role of three MYB2R3 proteins in cell cycle control. Arabidopsis plants that have mutations in three repressor type-myb3r genes display enlarged organs. In addition, MYB3R3 binds to G2/M-specific genes and associates with the repressor-type E2F and RBR proteins. The authors perform a range of pair-wise interaction studies to identify components of multiprotein complexes, that have also been identified in other organisms. Ultimately they show that these MYC3R genes are important for periodic expression during the cell cycle and for establishing a post-mitotic quiescent state that determines organ size.

Preview Article in EMBO Journal

 

Kohoutová L1, Kourová H1, Nagy SK2, Volc J1, Halada P1, Mészáros T2,3, Meskiene I4,5, Bögre L6, Binarová P1 (2015) The Arabidopsis mitogen-activated protein kinase 6 is associated with γ-tubulin on microtubules, phosphorylates EB1c and maintains spindle orientation under nitrosative stress New Phytologist. http://dx.doi.org/10.1111/nph.13501

Laszlo Bogre also features as a collaborator in this East European-led study that investigated the interaction of the MAPK-protein MPK6 with microtubules. Immunoprecitations showed that the active form of MPK6 interacted with γ-tubulin, sedimenting with in vitro polymerised microtubules. In addition they identified a novel substrate for MPK6, the microtubule plus-end protein, EB1c. Overall the authors propose that MPK6 plays a significant role in maintaining regular planes of cell division, particularly during stress conditions.

 

Lu H, Chandrasekar B, Oeljeklaus J, Misas-Villamil JC, Wang Z, Shindo T, Bogyo M, Kaiser M, van der Hoorn RA (2015) Subfamily-specific Fluorescent Probes for Cys proteases Display Dynamic Protease Activities During Seed Germination. Plant Physiology http://dx.doi.org/10.1104/pp.114.254466

Renier Van De Hoorn who works in the Department of Plant Chemetics at the University of Oxford, leads this study that investigates the activity of plant cysteine proteases. They developed a novel set of fluorescent probes that specifically target different subfamilies of Cys proteases. In order to test these probes they used Arabidopsis mutant lines alongside transient expression studies in tobacco. In addition they show that these probes have broad applicable across 8 plant species. Finally they use these new tools to reveal the dynamic properties of different protease sub-families during remobilization of seed storage proteins in Arabidopsis.