Salicylic Acid Targets Protein Phosphatase 2A to Attenuate Growth in Plants

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

Corresponding author: Jiří Friml

Plants, like other multicellular organisms, survive through a delicate balance between growth and defense against pathogens. Salicylic acid (SA) is a major defense signal in plants, and the perception mechanism as well as downstream signaling activating the immune response are known. Here, we identify a parallel SA signaling that mediates growth attenuation. SA directly binds to A subunits of protein phosphatase 2A (PP2A), inhibiting activity of this complex. Among PP2A targets, the PIN2 auxin transporter is hyperphosphorylated in response to SA, leading to changed activity of this important growth regulator. Accordingly, auxin transport and auxin-mediated root development, including growth, gravitropic response, and lateral root organogenesis, are inhibited. This study reveals how SA, besides activating immunity, concomitantly attenuates growth through crosstalk with the auxin distribution network. Further analysis of this dual role of SA and characterization of additional SA-regulated PP2A targets will provide further insights into mechanisms maintaining a balance between growth and defense.

植物与其它的多细胞生物一样，在生长和病原菌抗性之间存在一个微妙的平衡，从而可以保证生存。水杨酸SA是植物中主要的防御信号，目前我们对于植物感知SA的机制以及下游激活免疫响应的信号通路都已经了解。本文中，作者鉴定到了一个平行的SA信号通路，介导植物的生长衰减。SA能够直接结合到蛋白磷酸酶PP2A的亚基上，抑制该复合物的活性。在PP2A的靶标中，PIN2生长素转运蛋白响应于SA处理而表现出超磷酸化状态，从而导致这一重要生长调控因子的活性变化。于是，生长素转运蛋白和生长素介导的根发育，包括生长、重力响应以及侧根的器官发生等都被抑制。本文的研究揭示了SA除了激活免疫外，是如何通过与生长素分布网络的交联共同作用于生长衰减的。对于SA双重作用的进一步研究以及其它依赖于SA调控的PP2A靶基因的鉴定将会为植物中生长与防御之间微妙平衡的维持提供新的视野。

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/10.1016/j.cub.2019.11.058

Journal: Current Biology

Published date: January 16, 2020