Natural herbicides that are based on allelopathy of compounds, can offer effective alternatives to chemical herbicides towards sustainable agricultural practices. Nerolidol, a sesquiterpenoid alcohol synthesized by many plant families, was shown to be the most effective allelopathic compound in a preliminary screening performed with several other sesquiterpenoids. In the present study, Arabidopsis thaliana seedlings were treated for 14 d with various cis-nerolidol concentrations (0, 50, 100, 200, 400, and 800 µM) to investigate its effects on root growth and morphology. To probe the underlying changes in root metabolome, we conducted untargeted gas chromatography mass spectrometry (GC-MS) based metabolomics to find out the specificity or multi-target action of this sesquiterpenoid alcohol. Oxidative stress (measured as levels of H₂O₂ and malondialdehyde (MDA) by-product) and antioxidant enzyme activities, i.e., superoxide dismutase (SOD) and catalase (CAT) were also evaluated in the roots. Nerolidol showed an IC₅₀ (120 µM), which can be considered low for natural products. Nerolidol caused alterations in root morphology, brought changes in auxin balance, induced changes in sugar, amino acid, and carboxylic acid profiles, and increased the levels of H₂O₂ and MDA in root tissues in a dose-dependent manner. Several metabolomic-scale changes induced by nerolidol support the multi-target action of nerolidol, which is a positive feature for a botanical herbicide. Though it warrants further mechanistic investigation, nerolidol is a promising compound for developing a new natural herbicide.

中文翻译：

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倍半萜神经甾醇对拟南芥幼苗根的植物毒性，形态和代谢作用

基于化合物的化感作用的天然除草剂可以为可持续农业实践提供有效的化学除草剂替代品。Nerolidol是一种由许多植物家族合成的倍半萜醇，在与其他几种倍半萜的初步筛选中，Nerolidol是最有效的化感化合物。在本研究中，拟南芥用各种浓度（0、50、100、200、400和800 µM的顺式-橙皮醇）处理幼苗14天，以研究其对根系生长和形态的影响。为了探究根代谢组的潜在变化，我们进行了基于非目标气相色谱质谱（GC-MS）的代谢组学研究，以发现这种倍半萜醇的特异性或多目标作用。还评估了根部的氧化应激（以H ₂ O ₂和丙二醛（MDA）副产物的水平衡量）和抗氧化酶活性，即超氧化物歧化酶（SOD）和过氧化氢酶（CAT）。Nerolidol显示IC ₅₀（120 µM），对于天然产品而言可以认为很低。Nerolidol引起根部形态改变，生长素平衡变化，诱导糖，氨基酸和羧酸分布变化，并以剂量依赖性方式增加根部组织中H ₂ O ₂和MDA的含量。nerolidol引起的几种代谢组学规模的变化支持nerolidol的多目标作用，这是植物性除草剂的一个积极特征。尽管需要进一步的机理研究，但奈洛多是开发新型天然除草剂的有前途的化合物。