National Institute of Plant Genome Research (NIPGR), Aruna Asaf Ali Marg, P.O. Box 10531, New Delhi, 110067, India.
Planta. 2018 Oct;248(4):981-997. doi: 10.1007/s00425-018-2953-3. Epub 2018 Jul 9.
Metabolite profiling, biochemical assays, and transcript analysis revealed differential modulation of specific induced defense responses in local, older, and younger systemic leaves in Solanum lycopersicum upon Spodoptera litura herbivory. Plants reconfigure their metabolome upon herbivory to induce production of defense metabolites involved in both direct and indirect defenses against insect herbivores. Herbivory mediated leaf-to-leaf systemic induction pattern of primary and non-volatile secondary metabolites is not well studied in tomato. Here, we show that, in cultivated tomato Solanum lycopersicum herbivory by generalist insect, Spodoptera litura results in differential alteration of primary metabolites, majorly sugars and amino acids and specific secondary metabolites in local, younger, and older systemic leaves. Cluster analysis of 55 metabolites identified by GC-MS showed correlation between local and younger systemic leaves. Re-allocation of primary metabolites like glucose and amino acids from the local to systemic leaf was observed. Secondary metabolites chlorogenic acid, caffeic acid, and catechin were significantly induced during herbivory in systemic leaves. Among specific secondary metabolites, chlorogenic acid and catechin significantly inhibits S. litura larval growth in all stages. Local leaf exhibited increased lignin accumulation upon herbivory. Differential alteration of induced defense responses like reactive oxygen species, polyphenol oxidase activity, proteinase inhibitor, cell wall metabolites, and lignin accumulation was observed in systemic leaves. The metabolite alteration also resulted in increased defense in systemic leaves. Thus, comparative analysis of metabolites in local and systemic leaves of tomato revealed a constant re-allocation of primary metabolites to systemic leaves and differential induction of secondary metabolites and induced defenses upon herbivory.
代谢组学分析、生化测定和转录分析表明，在烟粉虱取食后，番茄的局部、较老和较年轻的系统叶中特定诱导防御反应受到不同调节。植物在受到取食后会重新配置其代谢组，以诱导产生参与直接和间接防御昆虫取食的防御代谢物。在番茄中，关于植物通过叶片间系统诱导模式来产生初级和非挥发性次生代谢物以抵御昆虫取食的研究还不够深入。在这里，我们表明，在普通昆虫烟粉虱取食栽培番茄时，局部、较年轻和较老的系统叶中的初级代谢物（主要是糖和氨基酸）和特定的次生代谢物发生了不同的变化。通过 GC-MS 鉴定的 55 种代谢物的聚类分析表明，局部和较年轻的系统叶之间存在相关性。从局部叶到系统叶的初级代谢物如葡萄糖和氨基酸的重新分配被观察到。次生代谢物绿原酸、咖啡酸和儿茶素在系统叶中受到取食的显著诱导。在特定的次生代谢物中，绿原酸和儿茶素在所有阶段都显著抑制烟粉虱幼虫的生长。局部叶在取食后木质素积累增加。系统叶中观察到诱导防御反应的差异变化，如活性氧、多酚氧化酶活性、蛋白酶抑制剂、细胞壁代谢物和木质素积累。代谢物的改变也导致系统叶中的防御增强。因此，番茄局部和系统叶代谢物的比较分析揭示了初级代谢物向系统叶的持续再分配，以及次生代谢物和诱导防御的差异诱导。
