Auxin and cytokinin are key endogenous regulators of plant development. Although cytokinin-mediated modulation of auxin distribution is a developmentally crucial hormonal interaction, its molecular basis is largely unknown. Here we show a direct regulatory link between cytokinin signalling and the auxin transport machinery uncovering a mechanistic framework for cytokinin-auxin cross-talk. We show that the CYTOKININ RESPONSE FACTORS (CRFs), transcription factors downstream of cytokinin perception, transcriptionally control genes encoding PIN-FORMED (PIN) auxin transporters at a specific PIN CYTOKININ RESPONSE ELEMENT (PCRE) domain. Removal of this cis-regulatory element effectively uncouples PIN transcription from the CRF-mediated cytokinin regulation and attenuates plant cytokinin sensitivity. We propose that CRFs represent a missing cross-talk component that fine-tunes auxin transport capacity downstream of cytokinin signalling to control plant development.
This work was supported by the European Research Council Starting Independent Research grant (ERC-2007-Stg-207362-HCPO to E.B., M.S., C.C.), by the Ghent University Multidisciplinary Research Partnership ‘Biotechnology for a Sustainable Economy’ no.01MRB510W, by the Research Foundation—Flanders (grant 3G033711 to J.-A.O.), by the Austrian Science Fund (FWF01_I1774S) to K.Ö.,E.B., and by the Interuniversity Attraction Poles Programme (IUAP P7/29 ‘MARS’) initiated by the Belgian Science Policy Office. I.D.C. and S.V. are post-doctoral fellows of the Research Foundation—Flanders (FWO). This research was supported by the Scientific Service Units (SSU) of IST-Austria through resources provided by the Bioimaging Facility (BIF), the Life Science Facility (LSF).
Šimášková M, O’Brien J, Khan-Djamei M, et al. Cytokinin response factors regulate PIN-FORMED auxin transporters. Nature Communications. 2015;6. doi:10.1038/ncomms9717
Šimášková, M., O’Brien, J., Khan-Djamei, M., Van Noorden, G., Ötvös, K., Vieten, A., … Benková, E. (2015). Cytokinin response factors regulate PIN-FORMED auxin transporters. Nature Communications, 6. https://doi.org/10.1038/ncomms9717
Šimášková, Mária, José O’Brien, Mamoona Khan-Djamei, Giel Van Noorden, Krisztina Ötvös, Anne Vieten, Inge De Clercq, et al. “Cytokinin Response Factors Regulate PIN-FORMED Auxin Transporters.” Nature Communications 6 (2015). https://doi.org/10.1038/ncomms9717.
M. Šimášková et al., “Cytokinin response factors regulate PIN-FORMED auxin transporters,” Nature Communications, vol. 6, 2015.
Šimášková M, O’Brien J, Khan-Djamei M, Van Noorden G, Ötvös K, Vieten A, De Clercq I, Van Haperen J, Cuesta C, Hoyerová K, Vanneste S, Marhavy P, Wabnik KT, Van Breusegem F, Nowack M, Murphy A, Friml J, Weijers D, Beeckman T, Benková E. 2015. Cytokinin response factors regulate PIN-FORMED auxin transporters. Nature Communications. 6, 8717.
Šimášková, Mária, et al. “Cytokinin Response Factors Regulate PIN-FORMED Auxin Transporters.” Nature Communications, vol. 6, 8717, Nature Publishing Group, 2015, doi:10.1038/ncomms9717.