Xu Ping, Fundneider Sophia, Lange Birgit, Maksym Rafał, Stuttmann Johannes, Schäffner Anton R
Institute of Biochemical Plant Pathology, Helmholtz Zentrum München, Neuherberg, Germany.
CEA, CNRS, BIAM, UMR7265, LEMiRE (Rhizosphère et Interactions Sol-Plante-Microbiote), Aix Marseille University, Saint-Paul lez Durance, France.
Nat Plants. 2025 Jul 22. doi: 10.1038/s41477-025-02053-2.
Soil-borne microorganisms can systemically affect shoot resistance to pathogens relying on jasmonic acid and/or salicylic acid. However, the emanating root triggers in these scenarios remain elusive. Here we identify an N-hydroxypipecolic-acid-(NHP-)directed, salicylic-acid-related mechanism of root-triggered systemic resistance in Arabidopsis, which uses components of systemic acquired resistance known in leaves. However, in contrast to the inductive nature of systemic acquired resistance, FLAVIN-DEPENDENT MONOOXYGENASE 1 (FMO1) continuously synthesizes NHP in roots, while the glucosyltransferase UGT76B1 concomitantly conjugates and immobilizes NHP. Physical grafting experiments and tissue-specific knockouts revealed that the loss of UGT76B1 in roots leads to enhanced NHP release, initiating shoot responses. This counteracting standby FMO1/UGT76B1 circuit is specifically and sensitively modulated by root-associated microorganisms. Endophytic and (hemi)biotrophic fungi induce UGT76B1 degradation and FMO1 expression, resulting in varying levels of NHP being released to the shoot, where this root signal differently modulates defence and growth.
土壤传播的微生物可以通过茉莉酸和/或水杨酸系统地影响地上部分对病原体的抗性。然而，在这些情况下，引发根系的触发因素仍然难以捉摸。在这里，我们在拟南芥中确定了一种由N-羟基哌啶酸（NHP）介导的、与水杨酸相关的根系触发的系统抗性机制，该机制利用了叶片中已知的系统获得性抗性的组成部分。然而，与系统获得性抗性的诱导性质不同，黄素依赖性单加氧酶1（FMO1）在根中持续合成NHP，而葡糖基转移酶UGT76B1则同时结合并固定NHP。物理嫁接实验和组织特异性敲除表明，根中UGT76B1的缺失会导致NHP释放增加，从而引发地上部分的反应。这种起抵消作用的备用FMO1/UGT76B1回路受到根际微生物的特异性和敏感调节。内生菌和（半）生物营养真菌诱导UGT76B1降解和FMO1表达，导致不同水平的NHP释放到地上部分，在那里这种根信号以不同方式调节防御和生长。
