Flavin Monooxygenase-Generated N-Hydroxypipecolic Acid Is a Critical Element of Plant Systemic Immunity

First author: Michael Hartmann; Affiliations: Heinrich Heine University (海因里希海涅大学): Düsseldorf, Germany

Corresponding author: Jürgen Zeier

Following a previous microbial inoculation (接种), plants can induce broad-spectrum immunity (广谱免疫) to pathogen infection, a phenomenon known as systemic acquired resistance (SAR; 系统获得性抗性). SAR establishment in Arabidopsis thaliana is regulated by the Lys catabolite pipecolic acid (Pip; 哌啶酸) and flavin-dependent-monooxygenase1 (FMO1; 黄素依赖型单加氧酶). Here, we show that elevated Pip is sufficient to induce an FMO1-dependent transcriptional reprogramming of leaves that is reminiscent of SAR. In planta and in vitro analyses demonstrate that FMO1 functions as a pipecolate N-hydroxylase (甲基哌啶N-羟化酶), catalyzing the biochemical conversion of Pip to N-hydroxypipecolic acid (NHP; N-羟基哌啶酸). NHP systemically accumulates in plants after microbial attack. When exogenously applied, it overrides the defect of NHP-deficient fmo1 in acquired resistance and acts as a potent (强有力的) inducer of plant immunity to bacterial and oomycete (卵菌) infection. Our work has identified a pathogen-inducible L-Lys catabolic pathway in plants that generates the N-hydroxylated (N-羟基化) amino acid NHP as a critical regulator of systemic acquired resistance to pathogen infection.

在微生物接种后，植物能够在一定时间内获得对病原菌的光谱抗性，这种现象被称为系统获得性抗性SAR。SAR在拟南芥中的建立受到赖氨酸代谢产物哌啶酸Pip和黄素依赖型单加氧酶FMO1的调控。本文的研究显示植物体内Pip含量的提升足够诱导叶片中FMO1依赖型的转录重编程，以帮助植物获得SAR。在植物体内和体外的试验显示FMO1作为一个甲基哌啶N-羟化酶发挥作用，催化Pip向N-羟基哌啶酸NHP的化学转化。在植物被微生物侵染后，NHP在整个植物体内积累。当外施NHP时，其可以恢复fmo1突变体在获得新抗性中的缺陷，同时可以有效诱导植物对细菌和卵菌的侵染抗性。本文的研究鉴定了植物中一个L型赖氨酸讲解代谢通路，该通路产生的N-羟基化氨基酸NHP作为重要的调控子参与植物对于病原菌侵染的系统获得性抗性获取。

通讯：Jürgen Zeier (https://www.ceplas.eu/en/research/metabolic-interactions-ra-d/prof-dr-juergen-zeier/)

研究方向：胁迫诱导的代谢途径在代谢物、生化和遗传层面的演化。

doi: https://doi.org/10.1016/j.cell.2018.02.049

Journal: Cell

Published date: 22 March, 2018

（P.S. 欢迎关注微信公众号：微信号Plant_Frontiers）