Characterisation of a RNA Methyl Transferase in Arabidopsis thaliana

Eva Hellmann ¹ Raili Ruonala ^1,2 Donghwi Ko ¹ Hanna Help-Rinta-Rahko ² Huili Liu ⁶ Sedeer el-Showk ² Ronni Nielsen ³ Anders Haakonsson ³ Ondrej Novak ^4,10 Miriam Llorian ⁵ Tanya Waldie ¹ Zsuzsanna Bodi ⁷ Susanne Mandrup ³ Karin Ljung ⁴ Liisa Holm ² Rupert Fray ⁷ Markku Varjosalo ² Chris Smith ⁵ Ottoline Leyser ¹ Finn Kirpekar ³ Patrick Perkins ⁸ Steffen Heber ⁸ Serina Mazzoni-Putman ⁹ Anna N Stepanova ⁹ Jose M Alonso ⁹ Ykä Helariutta ^1,2

¹The Sainsbury Laboratory, University of Cambridge, UK
²Institute of Biotechnology / Department of Biosciences, University of Helsinki, Finland
³Department of Biochemistry and Molecular Biology, University of Southern Denmark, Denmark
⁴Department of Forest Genetics and Plant Physiology, Umeå Plant Science Centre, Sweden
⁵Department of Biochemistry, University of Cambridge, UK
⁶College of Agriculture, South China Agricultural University, China
⁷Plant Sciences Division, University of Nottingham, UK
⁸Bioinformatics Research Centre, North Carolina State University, USA
⁹Department of Plant and Microbial Biology, North Carolina State University, USA
¹⁰Laboratory of Growth Regulators, Palacky University Olomouc, Czech Republic

Plants produce biomass via primary and secondary meristems. One of those meristems having a huge impact on tree biomass production is the cambium that gives rise to phloem and xylem, the actual wood. Understanding factors that affect cambium activity and xylem development will help to improve growth, and with it, biomass production in plants. We study cambium and xylem development in the model system Arabidopsis thaliana. The primary root can serve as a model to study cell proliferation, differentiation and the interplay of the phytohormones auxin and cytokinin in those processes.

In a genetic screen for novel factors acting on the cytokinin and auxin regulated Arabidopsis primary root patterning we identified a mutant that is interrupted in an RNA methyl transferase gene. The mutant exhibits defects in growth, cytokinin contents and signalling. Furthermore, the mutation can induce the production of a storage root like structure in Arabidopsis thaliana, characteristic to some crop species (such as radish or turnip) of the Brassicaceae family. We report a further analysis of this phenomenon.