Pinstatic acid promotes auxin transport by inhibiting PIN internalization

First author: Akihiro Oochi; Affiliations: Okayama University of Science (冈山理工大学): Okayama, Japan

Corresponding author: Ken-ichiro Hayashi

Polar auxin transport plays a pivotal role in plant growth and development. PIN auxin efflux carriers regulate directional auxin movement by establishing local auxin maxima, minima, and gradients that drive multiple developmental processes and responses to environmental signals. Auxin has been proposed to modulate its own transport by regulating subcellular PIN trafficking via processes such as clathrin-mediated PIN endocytosis and constitutive recycling. Here, we further investigated the mechanisms by which auxin affects PIN trafficking by screening auxin analogs and identified pinstatic acid (PISA) as a positive modulator of polar auxin transport in Arabidopsis thaliana. PISA had an auxin-like effect on hypocotyl elongation and adventitious root formation via positive regulation of auxin transport. PISA did not activate SCFTIR1/AFBsignaling and yet induced PIN accumulation at the cell surface by inhibiting PIN internalization from the plasma membrane. This work demonstrates PISA to be a promising chemical tool to dissect the regulatory mechanisms behind subcellular PIN trafficking and auxin transport.

生长素的极性运输在植物的生长和发育过程中扮演着至关重要的作用。PIN是生长素极性运输的载体，通过建立区域化的生长素极值点和梯度控制生长素的定向移动，从而调控多个植物发育进程以及对环境信号的响应。有研究提出生长素能够通过网格蛋白介导的细胞内吞作用及组成型再循环调控PIN运输的亚细胞定位，从而调节自身的转运。本文，作者通过生长素类似物的筛选进一步研究了拟南芥中生长素影响PIN运输的分子机制，最终鉴定了PISA作为生长素极性运输的正向调控子。PISA具有类似于生长素的影响，能够通过正向调控生长素的转运促进下胚轴伸长和不定根形成。PISA并不会激活SCFTIR1/AFB信号通路，但能够通过抑制质膜上PIN蛋白的内化，从而促进PIN蛋白在细胞表面的积累。本文的研究揭示了PISA可以作为一种化学工具用于解析亚细胞层面的PIN运输和生长素转运的调控机制。

通讯：Ken-ichiro Hayashi (http://www.dbc.ous.ac.jp/labs/KHayashi/KhayashiEnglish.html)

研究方向：植物激素的调控机制

doi: https://doi.org/10.1104/pp.19.00201

Journal: Plant Physiology

First Published: April 01, 2019