Julia C Engelmann3,* Rosalia Deeken1,* Tobias Müller3, Günter Nimtz2, M Rob G Roelfsema1, Rainer Hedrich11Molecular Plant Physiology and Biophysics, Julius-von-Sachs Institute for Biosciences; 2Institute of Physics II, University of Cologne, Cologne, Germany; 3Department of Bioinformatics, Biocenter, University of Würzburg, Würzburg, Germany; *These authors contributed equally to this workAbstract: Mobile phone technology makes use of radio frequency (RF) electromagnetic fields transmitted through a dense network of base stations in Europe. Possible harmful effects of RF fields on humans and animals are discussed, but their effect on plants has received little attention. In search for physiological processes of plant cells sensitive to RF fields, cell suspension cultures of Arabidopsis thaliana were exposed for 24 h to a RF field protocol representing typical microwave exposition in an urban environment. mRNA of exposed cultures and controls was used to hybridize Affymetrix-ATH1 whole genome microarrays. Differential expression analysis revealed significant changes in transcription of 10 genes, but they did not exceed a fold change of 2.5. Besides that 3 of them are dark-inducible, their functions do not point to any known responses of plants to environmental stimuli. The changes in transcription of these genes were compared with published microarray datasets and revealed a weak similarity of the microwave to light treatment experiments. Considering the large changes described in published experiments, it is questionable if the small alterations caused by a 24 h continuous microwave exposure would have any impact on the growth and reproduction of whole plants.Keywords: suspension cultured plant cells, radio frequency electromagnetic fields, microarrays, Arabidopsis thaliana