ECHIDNA-mediated post-Golgi trafficking of auxin carriers for differential cell elongation

作者：Yohann Boutté, Kristoffer Jonsson, Heather E. McFarlane, Errin Johnson, Delphine Gendre, Ranjan Swarup, Jiřı́ Friml, Lacey Samuels, Stéphanie Robert, Rishikesh P. Bhalerao · 发表于：Proceedings of the National Academy of Sciences · 年份：2013 · DOI：10.1073/pnas.1309057110 · 被引用次数：97 · 研究领域：Plant Molecular Biology Research、Plant Reproductive Biology、Photosynthetic Processes and Mechanisms

The plant hormone indole-acetic acid (auxin) is essential for many aspects of plant development. Auxin-mediated growth regulation typically involves the establishment of an auxin concentration gradient mediated by polarly localized auxin transporters. The localization of auxin carriers and their amount at the plasma membrane are controlled by membrane trafficking processes such as secretion, endocytosis, and recycling. In contrast to endocytosis or recycling, how the secretory pathway mediates the localization of auxin carriers is not well understood. In this study we have used the differential cell elongation process during apical hook development to elucidate the mechanisms underlying the post-Golgi trafficking of auxin carriers in Arabidopsis. We show that differential cell elongation during apical hook development is defective in Arabidopsis mutant echidna (ech). ECH protein is required for the trans-Golgi network (TGN)-mediated trafficking of the auxin influx carrier AUX1 to the plasma membrane. In contrast, ech mutation only marginally perturbs the trafficking of the highly related auxin influx carrier LIKE-AUX1-3 or the auxin efflux carrier PIN-FORMED-3, both also involved in hook development. Electron tomography reveals that the trafficking defects in ech mutant are associated with the perturbation of secretory vesicle genesis from the TGN. Our results identify differential mechanisms for the post-Golgi trafficking of de novo-synthesized auxin carriers to plasma membr...