Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2020.07.30.228379v1?rss=1 Authors: Oliver, N., Salvalaio, M., Tiknaz, D., Schwarze, M., Kral, N., Kim, S.-J., Sena, G. Abstract: An efficient foraging strategy for plant roots relies on the ability to sense multiple physical and chemical cues in soil and to reorient growth accordingly (tropism). Root tropisms range from sensing gravity (gravitropism), light (phototropism), water (hydrotropism), touch (thigmotropism) and more. Electrotropism, also known as galvanotropism, is the phenomenon of aligning growth with external electric fields and currents. Although observed in a few species since the end of the 19th century, the molecular and physical mechanism of root electrotropism remains elusive, limiting the comparison to more defined sensing pathways in plants. Here we provide a first quantitative and molecular characterisation of root electrotropism in the model system Arabidopsis thaliana, showing that it does not depend on an asymmetric distribution of the plant hormone auxin, but that instead it requires the biosynthesis of a second hormone, cytokinin. We also show that the dose-response kinetics of root electrotropism follows a power law analogous to the one observed in common animal physiological reactions, suggesting universal properties. A full molecular and quantitative characterisation of root electrotropism would represent a step forward towards a better understanding of signal integration in plants, and an independent outgroup for comparative analysis of electroreception in animals and fungi. Copy rights belong to original authors. Visit the link for more info