ARABIDOPSIS RESEARCH ROUND-UPARABIDOPSIS RESEARCH ROUND-UP

13th Nov 2013

There are plenty of new UK Arabidopsis papers to catch up on this week, including new research from the Universities of Cambridge, Glasgow, Dundee and Nottingham, Imperial College London and Rothamsted Research. Four out of six of this week's papers are published in open access journals, too! 

 

  • Wydro MM, Sharma P, Foster JM, Bych K, Meyer EH and Balk J. The evolutionarily conserved iron-sulphur protein INDH1 is required for Complex I assembly and mitochondrial translation in Arabidopsis. The Plant Cell, October 2013. DOI: 10.​1105/​tpc.​113.​117283 (opens PDF). [Open Access]

Janneke Balk is now at the John Innes Centre but worked on this paper with former colleagues from the University of Cambridge. Here, they describe experiments to characterize the role of the iron-sulphur protein INDH1. Using Arabidopsis thaliana, the team identified from indh mutants that Complex I was missing from the proteome, but it did have low levels of an intermediate in the complex assembly process. When expression of INDH was gradually increased in indh knockout plants, a delay in complex reassembly was observed. This suggests that INDH is indirectly involved in the assembly process. Furthermore, INDH is thought to have a primary role in mitochondrial translation that underlies its role in Complex I assembly.  

 

  • Wang Y, Chen Z-H, Zhang B, Hills A and Blatt MR. PYR/PYL/RCAR abscisic acid receptors regulate K+ and CL- channels through reactive oxygen species-mediated activation of Ca2+ channels at the plasma membrane of intact Arabidopsis guard cells. Plant Physiology, October 2013. DOI: ​10.​1104/​pp.​113.​219758. [Open Access]

The pyrbactin-insensitive pyr/pyl1/pyl2/pyl4 quadruple mutant is linked to the connection between the START family of abscisic acid (ABA) receptors and ABA-evoked Ca2+ signals that bring about stomatal closure. However, the precise mechanisms of the signal cascade are difficult to elicit because of crosstalk between ABA’s multiple functions in the plant. In this Plant Physiology paper, Michael Blatt and colleagues from the Universities of Glasgow (Scotland) and Western Sydney (Australia) describe a method for recording CA2+ channels at the plasma membrane of intact guard cells of Arabidopsis thaliana. Using this method, they determine that PYR/PYL/RCAR receptors are indeed linked to the regulation of stomatal closure via a specific mechanism.

 

  • Duc C, Sherstnev A, Cole C, Barton GJ and Simpson GG. Transcription termination and chimeric RNA formation controlled by Arabidopsis thaliana FPA. PLOS Genetics, 31 October 2013. DOI: 10.1371/journal.pgen.1003867. [Open Access]

This open access PLOS Genetics paper comes from plant scientists at the University of Dundee. Having already identified a rare example of a polyadenylation regulating protein (FPA) , here the team use direct RNA sequencing to demonstrate the consequences to transcription in fpa mutants. One of the most striking findings is that in the absence of FPA, chimeric RNAs are formed between two otherwise separate and well-characterised genes.

 

  • Plackett ARG, Ferguson AC, Powers SJ, Wanchoo-Kohli A, Phillips AL, Wilson ZA, Hedden P and Thomas SG. DELLA activity is required for successful pollen development in the Columbia ecotype of Arabidopsis. New Phytologist, 1 November 2013. DOI: 10.1111/nph.12571.

It had previously been assumed that DELLA activity was not essential for pollen development in Arabidopsis thaliana, thanks to studies using the ecotype Landsberg erecta (Ler). However, this paper, involving authors from the University of Nottingham and Rothamsted Research shows that this assumption was likely wrong. Rather, DELLA activity is not essential for pollen development in Ler, but does seem to be essential in wild type A. thaliana

 

  • Mathelier A, Zhao X, Zhang AW, et al. JASPAR 2014: an extensively expanded and updated open access database of transcription factor binding profiles. Nucleic Acids Research, 4 November 2013. DOI: 10.1093/nar/gkt997.  [Open Access]

In this multi-author, multinational paper (which included Boris Lenhard from Imperial College London), the latest version of the open access database JASPAR is described. JASPAR 2014 (http://jaspar.genereg.net) is a database of matrix-based nucleotide profiles describing the binding preferences of transcription factors from multiple species. This latest version includes 135 new profiles, including 43 new profiles from Arabidopsis thaliana.

 

  • Richards SL, Laohavisit A, Mortimer JC, Shabala L, Swarbreck SM, Shabala S, Davies JM. Annexin 1 regulate the H2O2-induced calcium signature in Arabidopsis thaliana roots. The Plant Journal, 4 November 2013. DOI: 10.1111/tpj.12372

Until now, only the Stelar K+ Outward Rectifier (SKOR) channel has been genetically shown to be responsive to the reactive oxygen species hydrogen peroxide (H22). This elevates cytosolic free Ca2+ as a second messenger in stress responses. However, researchers from the University of Cambridge, together with Japanese and Australian collaborators, have shown that Annexin 1 in Arabidopsis thaliana (AtANN1) is also sensitive to H22 and seems to be involved in regulation of the cytosolic free Ca2+ levels in root epidermal stress.