Weeding the Gems

Apologies there hasn’t been an Arabidopsis Research Round-up for a few weeks, I’ve been on annual leave getting married! Here’s a catch up of the newest Arabidopsis research papers from the UK community over the last month, including one from a GARNet committee member, and one from a former GARNet PI.

• Schatlowski N, Wolff P, Santos-González J, Schoft V, Siretskiy A, Scott R, Tamaru H and Köhler C. Hypomethylated pollen bypasses the interploidy hybridization barrier in Arabidopsis. The Plant Cell, 1 September 2014. DOI: 10.1105/tpc.114.130120.

Rod Scott from the University of Bath was involved on this Plant Cell paper. With Swedish, Austrian and Swiss colleagues, it was identified that, through the suppression of expressed imprinted genes, hypomethylation can occur in pollen that alters the epigenetic control of the ‘interploidy hybridization barrier’. Based on these findings, the researchers here present a novel method for the generation of viable triploid Arabidopsis plants, which could have significant impact for plant breeding.

• Chew YH, Wenden B, Flis A, et al. Multiscale digital Arabidopsis predicts individual organ and whole-organism growth. Proceedings of the National Academy of Sciences of the United States of America, 2 September 2014. DOI: 10.1073/pnas.1410238111. [Open Access]

You can tell former GARNet PI Andrew Millar from the University of Edinburgh led this paper – it’s all about linking the Arabidopsis research community! Quantitative modeling is undeniably an important tool in modern predictive biology, but understanding plants at a molecular level doesn’t necessarily help us to ‘bridge the genotype to phenotype gap’ and predict how molecular changes affect the whole organism, or vice versa. Linking together several models across multiple scales, Millar and colleagues here present a validated multiscale model of Arabidopsis rosette growth, enabling prediction of how genetic regulation and biochemical dynamics may affect organ and whole-plant growth.

• Chao D-Y, Baraniecka P, Danku J, Koprivova A, Lahner B, Luo H, Yakubova E, Dilkes BP, Kopriva S and Salt DE. Variation in sulfur and selenium accumulation is controlled by naturally occurring isoforms of the key sulfur assimilation enzyme APR2 across the Arabidopsis thaliana species range. Plant Physiology, 18 September 2014. DOI: 10.1104/pp.114.247825. [Open Access]

GARNet committee member and ‘Mr Ionomics’ David Salt, from the University of Aberdeen, was the lead on this new paper in Plant Physiology, working with colleagues from the John Innes Centre, Purdue, Cologne and Shanghai. This study used linkage mapping in synthetic F2 populations to investigate the natural variation in total leaf sulphur and selenium levels across a wide range of Arabidopsis thaliana accessions. Though the significance is not yet understood, it was found that the catalytic capacity of APR2, an enzyme important in allowing the accumulation of sulphur and selenium in leaves, varied by four orders of magnitude.

• Fujikura U, Elsaesser L, Breuninger H, Sanchez-Rodriguez C, Ivakov A, Laux T, Findlay K, Persson S and Lenhard M. Atkinesin-13A modulates cell wall synthesis and cell expansion in Arabidopsis thaliana via the THESEUS1 pathway. PLOS Genetics, 18 September 2014. DOI: 10.1104/pp.114.247825. [Open Access]

For plants to grow they need to not only proliferate their cells, but expand the size of the cells too. Since plant cells are encased in a rigid cell wall, the cell wall structure must be temporarily loosened to allow expansion and the deposition of additional cell wall materials. Working with a German-led team and colleagues in Australia, Kim Findlay from the John Innes Centre contributed to this paper, which discusses the roles of AtKINESIN-13-A and its homologue AtKINESIN-13B in limiting cell expansion and size in Arabidopsis thaliana.

• Johansson H, Jones HJ, Foreman J, Hemsted JR, Stewart K, Grima R and Halliday KJ. Arabidopsis cell expansion is controlled by a photothermal switch.Nature Communications, 26 September 2014. DOI: 10.1038/ncomms5848. [Open Access]

A second appearance in today’s Round-up for the University of Edinburgh’s Karen Halliday, and another paper discussing cell expansion. This time, this Nature Communications paper explores the finding that phytochrome B-controlled growth in the Arabidopsis hypocotyl is strictly regulated by temperature: a shift in temperature induces a dramatic reversal of response from inhibition to promotion of hypocotyl elongation by light.