Evolution of fast root gravitropism in seed plants

First author: Yuzhou Zhang; Affiliations: Institute of Science and Technology (奥地利科学技术研究所): Klosterneuburg, Austria

Corresponding author: Jiří Friml 

An important adaptation during colonization of land by plants is gravitropic growth of roots, which enabled roots to reach water and nutrients, and firmly anchor plants in the ground. Here we provide insights into the evolution of an efficient root gravitropic mechanism in the seed plants. Architectural innovation, with gravity perception constrained in the root tips along with a shootward transport route for the phytohormone auxin, appeared only upon the emergence of seed plants. Interspecies complementation and protein domain swapping revealed functional innovations within the PIN family of auxin transporters leading to the evolution of gravitropism-specific PINs. The unique apical/shootward subcellular localization of PIN proteins is the major evolutionary innovation that connected the anatomically separated sites of gravity perception and growth response via the mobile auxin signal. We conclude that the crucial anatomical and functional components emerged hand-in-hand to facilitate the evolution of fast gravitropic response, which is one of the major adaptations of seed plants to dry land.

植物殖民陆地过程中一个重要的适应性演化就是根的向重力生长，该能力使得植物的根能够接收到水分和营养，并且能够将植物牢牢地固定在陆地上。本文中，作者的研究揭示了种子植物中根向重力机制的演化历史。似乎从种子植物开始，植物的根才出现了结构性的创新，包括根尖组织对于重力的感知以及对于植物激素生长素向地上部分的运输。种间互补试验及蛋白结构域置换试验显示生长素转运蛋白PIN家族上的功能创新是导致PIN能够特异性感受重力的演化基础。PIN蛋白独特的尖端/茎朝向的亚细胞定位是主要的演化创新，通过移动的生长素信号将在结构上分离的两个部位：重力感知点和生长响应点联系在一起。作者认为关键的解剖学结构和功能组件的同时出现加速了植物的重力快速响应演化，而这是种子植物对干旱陆地的主要适应之一。

通讯：Jiří Friml (https://ist.ac.at/research/research-groups/friml-group/)

个人简介：1995年，马萨里克大学，化学学士；1997年，马萨里克大学，生物化学学士；2000年，科隆大学，生物学博士；2002年，马萨里克大学，生物化学博士。

研究方向：生长素的极性运输；细胞极性；细胞内吞与再循环；信号转导的非转录机制。

doi: https://doi.org/10.1038/s41467-019-11471-8

Journal: Nature Communications

Published date: August 02, 2019