ARABIDOPSIS RESEARCH ROUND-UPARABIDOPSIS RESEARCH ROUND-UP

16th Mar 2015

Here’s your UK Arabidopsis Research Round-up for the last few weeks! This week we have new papers from a range of UK institutions including the Universities of Birmingham, Cambridge, Oxford and Warwick, Queen’s University Belfast, Rothamsted Research, and the John Innes Centre, NIAB and The Sainsbury Laboratory, Norwich.

 

  • Roitinger E, Hofer M, Köcher T, et al. Quantitative phosphoproteomics of the Ataxia Telangiectasia-Mutated (ATM) and Ataxia Telangiectasia-Mutated and Rad3-related (ATR) dependent DNA damaga response in Arabidopsis thaliana. Molecular & Cellular Proteomics, 5 January 2015. DOI: 10.1074/mcp.M114.040352.

Jianhua Yang from the University of Birmingham worked with Austrian collaborators for his contribution to this paper, which describes a novel protocol for the phosphoproteomic assessement of DNA damage in Arabidopsis thaliana. The protocol combines filter-aided sample preparation, immobilised metal affinity chromatography, metal oxide affinity chromatography, and strong cation exchange chromatography for phosphopeptide generation, enrichment, and separation.

 

  • Knuesting J, Riondet C, Maria C, et al. Arabidopsis glutaredoxin S17 and its partner NF-YC11/NC2α contribute to maintenance of the shoot apical meristem under long-day photoperiod. Plant Physiology, 10 February 2015. DOI: 10.1104/pp.15.00049.

This study describes the work of an international team – including Inga Kruse and Janneke Balk from the John Innes Centre – to characterise the role of the glutaredoxin protein GRXS17 in Arabidopsis thaliana. Combining biochemical, genetic and physiological approaches, the group found that GRXS17’s primary function is to act as a disulphide oxidoreductase. In combination with a partner protein, the nuclear transcriptional regulator NF-YC11/NC2α, GRXS17 is thought to relay a redox signal generated by photoperiod to maintain meristem function.

 

  • Molojwane E, Adams N, Sweetlove LJ and Ingle RA. Heterologous expression of mitochondria-targeted microbial nitrilase enzymes increases cyanide tolerance in Arabidopsis. Plant Biology, 25 February 2015. DOI: 10.1111/plb.12323.

Plants can be used to remove toxic chemicals such as cyanide from the soil in a process known as bioremediation. However, the ability of plants to endogenously degrade cyanide can be easily overwhelmed in soils with a high cyanide concentration. Working with South African collaborators, Lee Sweetlove from the University of Oxford here describes work to genetically engineer an Arabidopsis line expressing a microbial nitrilase enzyme to improve the plant’s cyanide degradation capacity.

 

  • Zhang H, Deery MJ, Gannon L, Powers SJ, Lilley KS and Theodolou FL. Quantitative proteomics analysis of the Arg/N-end rule pathway f targeted degradation in Arabidopsis roots. Proteomics, 27 February 2015. DOI: 10.1002/pmic.201400530.

This paper describes work by plant scientists at Rothamsted Research and the University of Cambridge to study the proteomes of the Arabidopsis mutants ate1/2 and prt6. PRT6 is responsible for the degradation of proteins with basic N-termini, while ATE1 and ATE2 convert other proteins to PRT6 substrates via post-translational arginylisation. Data from this work suggest that PRT6 does not have a marked impact on the global proteome of Arabidopsis roots and is likely involved in the controlled degradation of relatively few regulatory proteins.   

 

  • Gutierrez-Beltran E, Moschou PN, Smertenko AP and Bozhkov PV. Tudor staphylococcal nuclease links formation of stress granules and processing bodies with mRNA catabolism in Arabidopsis. The Plant Cell, 3 March 2015. DOI: 10.1105/tpc.114.134494.

Andrei Smertenko from Queen’s University Belfast was involved in this study to understand the molecular mechanisms underlying the role of Tudor Staphylococcal Nuclease (TSN) in normal plant development and stress tolerance. Here it is shown that, in Arabidopsis, TSN is essential for the integrity and function of cytoplasmic messenger ribonucleoprotein complexes called stress granules and processing bodies; sites of post-transcriptional gene regulation during stress. It is also shown that TSN has a positive role in stress-induced mRNA decapping.

 

  • Dupree R, Simmons TJ, Mortimer J, Patel D, Iuga D, Brown SP and Dupree P. Probing the molecular architecture of Arabidopsis thaliana secondary cell walls using two- and three-dimensional 13C solid-state NMR spectroscopy. Biochemistry, 4 March 2015. DOI: 10.1021/bi501552k.

Little is known about the role of the molecular architecture of secondary cell walls in plants, so to enhance our understanding in this area, new methods to analyse molecular architecture are required. This team of researchers from the University of Cambridge and the University of Warwick took 13C-labelled stems from Arabidopsis thaliana and subjected them to a number of 13C solid-state magic angle spinning NMR methods to assess the viability of these methods for molecular architecture analysis.

 

  • Webb AAR and Satake A. Understanding circadian regulation of carbohydrate metabolism in Arabidopsis using mathematical models. Plant & Cell Physiology, 5 March 2015. DOI: 10.1093/pcp/pcv033.

This useful paper, by Alex Webb of the University of Cambridge and a Japanese colleage Akiko Satake, reviews the literature linking carbon metabolism in plants and the circadian clock, as well as the mathematical models that are used to explain the diel starch profile in Arabidopsis. These mathematical models are in two classes: those that assume the level of available starch is sensed by the plant, allowing linearity of starch availability, and those in which sugar sensing is assumed, yielding linearity of starch availability as an emergent property of sucrose homeostasis.

 

  • Saucet SB, Ma Y, Sarris PF, Furzer OJ, Sohn KH and Jones JDG. Two linked pairs of Arabidopsis TNL resistance genes independently confer recognition of bacterial effector AvrRps4. Nature Communications, 6 March 2015. DOI: 10.1038/ncomms7338.

Scientists from The Sainsbury Laboratory in Norwich present this Nature Communications paper, which advances our understanding of paired resistance (R) gene function in Arabidopsis. Though the proteins RRS1-R and RPS4 both recognize the bacterial effectors AvrRps4 from Pseudomonas syringae and PopP2 from Ralstonia solanacearum, rrs1/rps4 mutants recognize AvrRps4 but not PopP2. Jonathan Jones’ team identifies an R gene pair – RRS1B/RPS4B – that resembles and is linked to RRS1/RPS4, which confers recognition of AvrRsp3 but not PopP2.

 

  • Pen Y, Chen L, Lu Y, Wu Y, Dumenil J, Zhu Z, Bevan MW and Li Y. The ubiquitin receptors Da1, DAR1, and DAR2 redundantly regulate endoreduplication by modulating the stability of TCP14/15 in Arabidopsis. The Plant Cell, 10 March 2015. DOI: 10.1105/tpc.114.132274.

The molecular mechanisms linking cell and organ growth with endoreduplication is poorly understood, though it has previously been shown by these authors that the ubiquitin receptor DA1 influences organ growth by restricting cell proliferation. This Plant Cell paper advances on this knowledge by revealing that the DA1’s close family members DAR1 and DAR2 are redundantly required for endoreduplication during leaf development.  DA1, DAR1 and DAR2 all physically interact with the transcription factors TCP14 and TCP15, which repress endoreduplication by directly regulating the expression of cell-cycle genes.

 

  • Schoonbeek H-j, Wang H-H, Stefanato FL, Craze M, Bowden S, Wallington E, Zipfel C and Ridout CJ. Arabidopsis EF-Tu receptor enhances bacterial disease resistance in transgenic wheat. New Phytologist, 11 March 2015. DOI: 10.1111/nph.13356.

The Norwich-based team behind this paper hails from the John Innes Centre, NIAB and The Sainsbury Laboratory – including GARNet committee member Cyril Zipfel. The work describes how a pattern recognition receptor (PRR) from Arabidopsis can be transgenically expressed in wheat, conferring resistance to Pseudomonas syringae pv. oryzae.  This is the first time a PRR from a monocot species has been successfully genetically engineered into a dicot plant – exciting news for model to crop translation!  

You can read more about this work on our News page, here: Scientists transfer pathogen-sensing 'antenna' gene to wheat