[植物演化] 植物根的向地性是如何演化出現的呢？ 20191118 Nature communication

Plasmodesmata
Nov 18, 2019
2 min read

Evolution of fast root gravitropism in seed plants

Yuzhou Zhang, Guanghui Xiao, Xiaojuan Wang, Xixi Zhang & Jiří Friml

Abstract

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 sepa- rated sites of gravity perception and growth response via the mobile auxin signal. We con- clude 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.

種子植物中，對於重力快速反應的演化

摘要

在植物登陸後，有一個很重要的適應環境的變化是根對於重力的反應。這個機制促進了對於植物攝取水分及養分，並且可以幫助植物牢牢固定在地面。在此，我們提供了在種子植物中，植物如何演化出對於重力的快速反應的一些證據。在構造上的創新，加上只在根尖可以接受到重力的限制，還有向莖頂傳輸生長素的現象，都是在種子植物演化出現時才同時發生的。跨物種的互補實驗以及蛋白質區域互換的實驗顯示，生長素運輸蛋白質家族（PIN）功能上的創新，引領了特別對於向地性有專一性的PIN的演化。特別座落在細胞朝向莖頂的PIN蛋白質的演化，造成了生長素分佈變化，接著引起訊息傳導，連接了感受到重力（根尖）和產生生長反應（根部生長區域）這兩個分開位置的組織。我們總結，在解剖學上和功能上重要的單位，一起手牽手的演化出現，加速了跟的快速重力反應的演進，對於種子植物適應乾燥陸地而言非常重要的。