ARABIDOPSIS RESEARCH ROUND-UPARABIDOPSIS RESEARCH ROUND-UP

2nd Sep 2013

Can you believe it is already September? There are plenty of new Arabidopsis papers to catch up on this week – the Universities of York and Warwick, and Rothamsted Research, have been especially busy!

 

  • Sanchez-Villarreal A, Shin J, Bujdoso N, et al. TIME FOR COFFEE is an essential component in the maintenance of metabolic homeostasis in Arabidopsis thaliana. The Plant Journal, 23 August 2013. DOI: 10.1111/tpj.12292.

 

Rising at dawn often means we need “time for coffee”, and Arabidopsis plants are no different. Under diurnal conditions, some metabolic and stress-related pathways are reprogrammed at night to provide fitness benefits to the plant, while the circadian promoter TIME FOR COFFEE (TIC) is known to be involved in resetting this clock at dawn. In this paper, the Max Planck team – led by Seth Davis of the University of York – carried out analysis of tic mutants and discovered that TIC is an essential component in many aspects of plant homeostasis, including the integration and coordination of developmental, metabolic and environmental signals.

 

  • Rosas U, Cibrian-Jaramillo A, Ristova D, et al. Integration of responses within and across Arabidopsis natural accessions uncovers loci controlling root systems architecture. Proceedings of the National Academy of Sciences USA, 26 August 2013. DOI: 10.1073/pnas.1305883110.

 

Plants within a species exhibit natural variation, and individual plants also exhibit phenotypic plasticity in response to environmental conditions – but are the genetic mechanisms underlying these variations related? This was the question posed by the international team collaborating on this PNAS paper, which included Dr Miriam Gifford from the University of Warwick. The paper presents findings that support a role for plasticity responses in phenotypic evolution in natural environments.

 

  • Brown L-A, Larson TR, Graham IA, Hawes C, Paudyal R, Warriner SL and Baker A. An inhibitor of oil body mobilization in Arabidopsis. New Phytologist, 27 August 2013. DOI: 10.1111/nph.12467.

 

Authors from the Universities of Leeds, York and Oxford Brookes worked together on this New Phytologist paper to characterise the effects of a small molecule, diphenyl methylphosphonate, on oil mobilization in Arabidopsis thaliana. Although its molecular target is not yet known, it was found that diphenyl methylphosphonate is a specific inhibitor of triacylglycerol (TAG) mobilisation. If the specific pathway(s) by which this process occurs can be understood in more detail, we may be able to manipulate oil mobilization in Arabidopsis and eventually in oil seed crops for food, biofuels and industrial feedstocks.

 

  • Sarnowska EA, Rolicka AT, Bucior E, et al. DELLA-interacting SWI3C core subunit of Switch/Sucrose Nonfermenting chromatin remodeling complex modulates giberellin responses and hormonal cross talk in Arabidopsis. Plant Physiology, September 2013. DOI: 10.​1104/​pp.​113.​223933.

 

While it is known that Arabidopsis plants with chromatin-remodelling complex (CRC) mutations exhibit severely impaired growth and development, it is not fully understood why. Here, Seth Davis at the University of York (again!) – working with colleagues from Poland, Japan, Germany and Hungary – suggests that DELLA-mediated effects in giberellin signaling and hormonal cross-talk may be dependent upon physical interaction with complexes responsible for the modulation of chromatin structure.

 

  • Mendes A, Kelly AA, van Erp H, Shaw E, Powers SJ, Kurup S and Eastmond PJ. bZIP67 regulates the omega-3 fatty acid content of Arabidopsis seed oil by activating FATTY ACID DESATURASE3. The Plant Cell, August 2013. DOI: 10.​1105/​tpc.​113.​116343.

 

GARNet committee member Smita Kurup and her colleagues from Rothamsted Research worked alongside a team from the University of Warwick to write this paper in The Plant Cell. The fatty acid alpha-linoleic acid (ALA), which is of significance not only in providing nourishment for germinating seeds, but also as an essential fatty acid for human health, is highly responsive to the level of FATTY ACID DESATURASE3 (FAD3) expression, which is strongly upregulated during embryogenesis. Through in vivo and in vitro studies, a complex mechanism for the activation of FAD3, and consequently ALA production, is proposed.

 

  • Zhu Q, Dugardeyn J, Zhang C, et al. The Arabidopsis thaliana RNA editing factor SLO2, which affects the mitochondrial electron transport chain, participates in multiple stress and hormone responses. Molecular Plant, 29 August 2013. DOI: 10.1093/mp/sst102.

 

As with the previous paper, this Molecular Plant offering also involved Peter Eastmond from Rothamsted Research. Following on from previous work that showed the RNA editing factor SLO2 to be involved in mitochondrial electron transport, here it is demonstrated that slo2 mutants are hypersensitive to abscissic acid (ABA) and insensitive to ethylene. This translates into a range of phenotypes, including adult plants that have increased drought and salt tolerance, and a susceptibility to Botrytis cinerea infection.