德国哥廷根大学的Ivo Feussner、Marcel Wiermer团队和加拿大英属哥伦比亚大学Yuelin Zhang团队合作报道了植物应激激素水杨酸的生物合成途径。该研究于2019年8月2日发表于国际学术期刊《科学》上。

研究人员希望知道异分支酸是如何以及在细胞哪个区域被转化为水杨酸。研究人员发现，在拟南芥中异分支酸合成通路下游仅需两个蛋白：EDS5和PBS3，前者将异分支酸从质体转运至胞浆，后者催化谷氨酸与异分支酸的结合产生isochorismate-9-glutamate，这个产物能够自发分解为水杨酸和2-hydroxy-acryloyl-N-glutamate。这项研究表明，这一仅需三个细胞定位不同的蛋白调控的单向合成流，可能保护了这一通路免受进化压力与病原体的干扰。

据悉，植物激素水杨酸(SA)调控植物的生物与非生物应激响应。质体产生的分支酸是水杨酸生物合成中的代谢产物。大多数病原体引起的水杨酸来源于异分支酸，这是由异分支酸合成酶将分支酸催化得来。

附：英文原文

Title: Isochorismate-derived biosynthesis of the plant stress hormone salicylic acid

Author: Dmitrij Rekhter, Daniel Lüdke, Yuli Ding, Kirstin Feussner, Krzysztof Zienkiewicz, Volker Lipka, Marcel Wiermer, Yuelin Zhang, Ivo Feussner

Issue&Volume: Vol 365 Issue 6452

Abstract: The phytohormone salicylic acid (SA) controls biotic and abiotic plant stress responses. Plastid-produced chorismate is a branch-point metabolite for SA biosynthesis. Most pathogen-induced SA derives from isochorismate, which is generated from chorismate by the catalytic activity of ISOCHORISMATE SYNTHASE1. Here, we ask how and in which cellular compartment isochorismate is converted to SA. We show that in Arabidopsis, the pathway downstream of isochorismate requires only two additional proteins: ENHANCED DISEASE SUSCEPTIBILITY5, which exports isochorismate from the plastid to the cytosol, and the cytosolic amidotransferase avrPphB SUSCEPTIBLE3 (PBS3). PBS3 catalyzes the conjugation of glutamate to isochorismate to produce isochorismate-9-glutamate, which spontaneously decomposes into SA and 2-hydroxy-acryloyl-N-glutamate. The minimal requirement of three compartmentalized proteins controlling unidirectional forward flux may protect the pathway against evolutionary forces and pathogen perturbations.

DOI: 10.1126/science.aaw1720

Source:https://science.sciencemag.org/content/365/6452/498