Rapid reconfigurations of interconnected phytohormone signalling networks allow plants to tune their physiology to constantly varying ecological conditions. During insect herbivory, most of the induced changes in defence‐related leaf metabolites are controlled by jasmonate (JA) signalling, which, in the wild tobacco Nicotiana attenuata, recruits MYB8, a transcription factor controlling the accumulation of phenolic‐polyamine conjugates (phenolamides). In this and other plant species, herbivory also locally triggers ethylene (ET) production but the outcome of the JA‐ET cross‐talk at the level of secondary metabolism regulation has remained only superficially investigated. Here, we analysed local and systemic herbivory‐induced changes by mass spectrometry‐based metabolomics in leaves of transgenic plants impaired in JA, ET and MYB8 signalling. Parsing deregulations in this factorial data‐set identified a network of JA/MYB8‐dependent phenolamides for which impairment of ET signalling attenuated their accumulation only in locally damaged leaves. Further experiments revealed that ET, albeit biochemically interrelated to polyamine metabolism via the intermediate S‐adenosylmethionine, does not alter the free polyamine levels, but instead significantly modulates phenolamide levels with marginal modulations of transcript levels. The work identifies ET as a local modulator of phenolamide accumulations and provides a metabolomics data‐platform with which to mine associations among herbivory‐induced signalling and specialized metabolites in N. attenuata.

中文翻译：

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乙烯是烟草天蛾食草期间茉莉酸依赖性酚酰胺积累的局部调节剂


相互关联的植物激素信号网络的快速重新配置使植物能够调整其生理机能以适应不断变化的生态条件。在昆虫食草过程中，防御相关叶子代谢物的大部分诱导变化是由茉莉酸 (JA) 信号传导控制的，在野生烟草中，该信号传导会招募 MYB8，这是一种控制酚类多胺缀合物（酚酰胺）积累的转录因子。在这种植物和其他植物物种中，食草也会局部触发乙烯（ET）的产生，但次级代谢调节水平上的 JA-ET 串扰的结果仍然只是表面研究。在这里，我们通过基于质谱的代谢组学分析了 JA、ET 和 MYB8 信号传导受损的转基因植物叶子中由食草动物引起的局部和全身变化。解析该阶乘数据集中的放松管制，确定了 JA/MYB8 依赖性酚酰胺网络，其中 ET 信号传导受损只会减弱其在局部受损叶片中的积累。进一步的实验表明，尽管 ET 通过中间体S-腺苷甲硫氨酸在生化上与多胺代谢相关，但它不会改变游离多胺水平，而是通过转录水平的边际调节来显着调节酚酰胺水平。这项工作将 ET 确定为酚酰胺积累的局部调节剂，并提供了一个代谢组学数据平台，用于挖掘食草诱导的信号传导和N. attenuata中的专门代谢物之间的关联。