Department of Food Science , Henan Institute of Science and Technology , Xinxiang 453003 , China.
Institute of Food Safety and Nutrition , Jiangsu Academy of Agricultural Sciences , Nanjing 210014 , China.
J Agric Food Chem. 2018 Sep 26;66(38):9914-9922. doi: 10.1021/acs.jafc.8b03098. Epub 2018 Sep 14.
Eugenol, a plant-derived small compound, shows great medicinal potential. However, whether and how eugenol regulates crop physiology remains elusive. Here we reported that eugenol induced Cd (cadmium) tolerance in the root of Brassica rapa. Roots were treated with eugenol and CdCl simultaneously (eugenol + Cd) or pretreated with eugenol followed by CdCl treatment (eugenol → Cd). Eugenol significantly attenuated Cd-induced growth inhibition, ROS accumulation, oxidative injury, and cell death, which were confirmed by in vivo histochemical analysis. Eugenol remarkably decreased free Cd accumulation in root. Eugenol intensified GSH (glutathione) accumulation in roots upon CdCl exposure, which explained the decrease in free Cd and attenuation of oxidative injury. Eugenol stimulated endogenous HS (hydrogen sulfide) generation by upregulating the expression of BrLCD ( l-cysteine desulfhydrase) and BrDCD ( d-cysteine desulfhydrase) as well as their enzymatic activities in CdCl-treated root. Application of HS biosynthesis inhibitor or HS scavenger led to the decrease in endogenous HS level in Cd-treated root, which further compromised all the above effects of eugenol. These findings suggested that eugenol triggered HS → GSH signaling cassette in plants to combat Cd stress, which shed new light on eugenol-modulated plant physiology and the interaction between eugenol and HS.
丁香酚是一种植物衍生的小分子化合物，具有巨大的药用潜力。然而，丁香酚是否以及如何调节作物生理学仍不清楚。在这里，我们报道了丁香酚诱导油菜根对镉（Cd）的耐受性。用丁香酚和 CdCl 同时处理（丁香酚+Cd）或用丁香酚预处理后再用 CdCl 处理（丁香酚→Cd）。结果发现，丁香酚显著减轻了 Cd 诱导的生长抑制、ROS 积累、氧化损伤和细胞死亡，这通过体内组织化学分析得到了证实。丁香酚显著减少了根中游离 Cd 的积累。丁香酚在 CdCl 暴露下增强了根中的 GSH（谷胱甘肽）积累，这解释了游离 Cd 的减少和氧化损伤的减轻。丁香酚通过上调 BrLCD（l-半胱氨酸脱硫酶）和 BrDCD（d-半胱氨酸脱硫酶）的表达及其在 CdCl 处理根中的酶活性，刺激内源性 HS（硫化氢）的产生。HS 生物合成抑制剂或 HS 清除剂的应用导致 Cd 处理根中内源性 HS 水平下降，进一步削弱了丁香酚的所有上述作用。这些发现表明，丁香酚在植物中触发了 HS→GSH 信号级联反应来应对 Cd 胁迫，这为丁香酚调节植物生理学和丁香酚与 HS 的相互作用提供了新的见解。
