Hormone transport in plants
Unlike animals, plants are sessile organisms and must integrate biotic and abiotic stimuli for continuous growth and development throughout their lifespan. For example, plants determine the timing and location of growth and development depending on the availability and quality of nutrients and water, herbivory and disease state. To make these signal integration processes, plants employ phytohormone response pathways, which are controlled at multiple levels including biosynthesis, metabolism, perception and signaling. In addition, plants also regulate the distribution and concentration gradients of phytohormones, enabling highly coordinated cellular responses. For example, the combined activity of auxin influx and efflux carrier proteins generates local auxin maxima and directional gradients that inform essential developmental patterning. Similarly, hormone radiolabeling and mutant grafting experiments indicate that jasmonic acid, abscisic acid and gibberellic acid are mobile phytohormones and that their movement is important for transmitting critical information such as wounding and drought and for coordinating growth.
Using a functional genomics approach we are currently focusing on identifying and characterizing transporter complements for JA, ABA and GA. We have built a comprehensive library of membrane transporters from Arabidopsis thaliana and use the Xenopus oocyte system for screening and biochemical characterization of new transporters using electrophysiology and LCMS based uptake assays. We aim to elucidate the mechanism and physiological role of phytohormone movement in plants, which we expect will lead to the development of new strategies for improving agricultural traits.
Eilon Shani, Tel Aviv University, Israel
Toshimitsu Kawate, Cornell University, USA
Human Frontier Science Program (HFSP) 2015-2018
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Tal I, Zhang Y, Jørgensen ME, Pisanty O, Barbosa ICR, Zourelidou M, Regnault T, Crocoll C, Olsen CE, Weinstain R, Schwechheimer C, Halkier BA, Nour-Eldin HH, Estelle M, Shani E (2016) The Arabidopsis NPF3 protein is a GA transporter. Nat Commun 7: 11486. DOI: 10.1038/ncomms11486
Hussam H. Nour-Eldin