Department AGRARIA, University Mediterranea of Reggio Calabria, Località Feo di Vito, SNC I-89124, Reggio Calabria, RC, Italy.
Department for Sustainable Food Process, Università Cattolica del Sacro Cuore, via Emilia Parmense 84, 29122, Piacenza, Italy.
Plant Physiol Biochem. 2020 Aug;153:141-153. doi: 10.1016/j.plaphy.2020.05.008. Epub 2020 May 18.
Thymol is a natural phenolic monoterpene widely produced by different species belonging to the Labiateae family. Although the thymol phytotoxicity is well known, the knowledge of its potential toxic mechanism is still limited. In this regard, the model species Arabidopsis thaliana was treated for 16 days by sub-irrigation with 300 μM of thymol. The results confirmed the high phytotoxic potential of this phenolic compound, which caused a reduction in plant growth and development. Thymol induced a water status alteration accompanied by an increase in ABA content and stomatal closure. Furthermore, leaves appeared necrotic in the margins and their temperature rinsed. The increase in HO content suggested an oxidative stress experienced by treated plants. Both metabolomic and proteomic analysis confirmed this hypothesis showing a strong increase in osmoprotectants content, such as galactinol and proline, and a significant up-accumulation of proteins involved in ROS detoxification. Furthermore, the down-accumulation of proteins and pigments involved in the photosynthetic machinery, the increase in light sensitivity and the lower PSII efficiency well indicated a reduction in photosynthetic activity. Overall, we can postulate that thymol-induced phytotoxicity could be related to a combined osmotic and oxidative stress that resulted in reduced plant development.
百里香酚是一种天然酚类单萜烯，广泛存在于唇形科的不同物种中。尽管百里香酚具有明显的植物毒性，但人们对其潜在的毒性机制仍知之甚少。在这方面，我们以拟南芥为模式植物，通过亚灌溉的方式用 300 μM 的百里香酚处理 16 天。结果证实了这种酚类化合物具有很强的植物毒性，它会导致植物生长和发育受阻。百里香酚会引起植物的水分状态改变，伴随着 ABA 含量的增加和气孔关闭。此外，叶片边缘出现坏死，并伴有温度下降。HO 含量的增加表明处理过的植物经历了氧化应激。代谢组学和蛋白质组学分析都证实了这一假设，表明植物中渗透调节剂（如半乳糖醇和脯氨酸）的含量显著增加，同时与 ROS 解毒相关的蛋白质大量积累。此外，与光合作用机制相关的蛋白质和色素的积累减少、对光的敏感性增加以及 PSII 效率的降低都表明光合作用活性降低。总的来说，我们可以假设，百里香酚诱导的植物毒性可能与渗透和氧化应激的联合作用有关，导致植物发育受阻。
