奥地利科学技术学院Friml, Ji及其小组发现根生长过程中调控H+通量的细胞表面和细胞内生长素信号机制。这一研究成果于2021年10月27日发表在国际学术期刊《自然》上。
通过在拟南芥中结合微流体、实时成像、基因工程和磷酸化蛋白质组学，研究人员进一步揭示了生长素如何抑制根系生长的机制。研究表明，生长素激活两种不同且具有拮抗作用的信号通路，这些通路主要在质外体pH快速调节过程中发挥作用，这是调控生长的决定因素。基于细胞表面的跨膜激酶1 (TMK1)与质膜H+-ATPases 相互作用介导磷酸化和信号激活以进行质外体酸化，而细胞内的经典生长素信号促进净细胞H+流入，导致质外体碱化。这两种抵消机制的同时激活为植物在复杂土壤环境中进行快速、适应性调节奠定了基础。
研究人员表示，生长调节使植物在发育过程中适应其环境。一个典型的例子是对重力的反应，其中枝条向上弯曲，根部向下弯曲。这个悖论是基于植物激素生长素的相反作用，它通过一种未知的细胞机制促进芽中的细胞扩张，同时在根中抑制其生长。
附：英文原文
Title: Cell surface and intracellular auxin signalling for H+ fluxes in root growth
Author: Li, Lanxin, Verstraeten, Inge, Roosjen, Mark, Takahashi, Koji, Rodriguez, Lesia, Merrin, Jack, Chen, Jian, Shabala, Lana, Smet, Wouter, Ren, Hong, Vanneste, Steffen, Shabala, Sergey, De Rybel, Bert, Weijers, Dolf, Kinoshita, Toshinori, Gray, William M., Friml, Ji
Issue&Volume: 2021-10-27
Abstract: Growth regulation tailors development in plants to their environment. A prominent example of this is the response to gravity, in which shoots bend up and roots bend down1. This paradox is based on opposite effects of the phytohormone auxin, which promotes cell expansion in shoots while inhibiting it in roots via a yet unknown cellular mechanism2. Here, by combining microfluidics, live imaging, genetic engineering and phosphoproteomics in Arabidopsis thaliana, we advance understanding of how auxin inhibits root growth. We show that auxin activates two distinct, antagonistically acting signalling pathways that converge on rapid regulation of apoplastic pH, a causative determinant of growth. Cell surface-based TRANSMEMBRANE KINASE1 (TMK1) interacts with and mediates phosphorylation and activation of plasma membrane H+-ATPases for apoplast acidification, while intracellular canonical auxin signalling promotes net cellular H+ influx, causing apoplast alkalinization. Simultaneous activation of these two counteracting mechanisms poises roots for rapid, fine-tuned growth modulation in navigating complex soil environments.
DOI: 10.1038/s41586-021-04037-6
Source: https://www.nature.com/articles/s41586-021-04037-6
Nature：《自然》，创刊于1869年。隶属于施普林格·自然出版集团，最新IF：69.504
官方网址：http://www.nature.com/
投稿链接：http://www.nature.com/authors/submit_manuscript.html
本期文章：《自然》：Online/在线发表
