Li Jingchong, Geng Runlian, Kong Xiangjun, Li Lijie, Zhang Zhiyong, Liu Runqiang
School of Life Science and Technology/School of Resources and Environment, Henan Institute of Science and Technology, Xinxiang, Henan 453003, China; University of the Chinese Academy of Sciences, Beijing 100049, China.
College of Life Science, Henan Normal University, Xinxiang, Henan 453007, China.
Ecotoxicol Environ Saf. 2023 Apr 15;255:114787. doi: 10.1016/j.ecoenv.2023.114787. Epub 2023 Mar 20.
Difenoconazole (DFZ) is a broad-spectrum fungicide widely applied in wheat production. However, excessive accumulation is linked to phytotoxicity. The effects of DFZ on plants and the response mechanisms to DFZ toxicity are poorly understood. Herein, the uptake, accumulation, and translocation of DFZ and induced changes in the morphology, physiology, and gene expression were investigated under hydroculture of roots treated with 50, 100, and 200 mg/L DFZ concentrations. Compared with the control, DEZ treatment upregulated the expression of genes encoding 4-coumarate-CoA ligase (4CL) and peroxidase (POD) involved in the lignin biosynthesis pathway and enhanced lignin biosynthesis. DFZ accumulated more in older leaves (cotyledons and lower true leaves), with 0.49-5.71 and 0.09-2.14 folds higher than levels in new upper leaves and roots, respectively. The excessive accumulation of DFZ in tissues was rapidly degraded, with a 15.7-69.3% reduction of DFZ content in roots and leaves from 3 DAT to 6 DAT. The genes expression and activity of glutathione S-transferase (GST) were increased. Furthermore, DFZ treatments upregulated genes encoding chalcone synthase (CHS), chalcone isomerase (CHI), and anthocyanidin synthase (ANS) involved in the flavonoid biosynthesis pathway and increased the amount of flavonoid and anthocyanins in leaves. This study provides new insights into the self-protective behaviors exhibited by wheat plants under DFZ stress. The mechanisms included hindering DFZ penetration from roots by enhancing lignin biosynthesis, accumulating more in old leaves, degrading by GST, and alleviating oxidative damage by increasing the content of flavonoids and anthocyanins in leaves.
苯醚甲环唑（DFZ）是一种广泛应用于小麦生产的广谱杀菌剂。然而，过量积累与植物毒性有关。人们对DFZ对植物的影响及其对DFZ毒性的响应机制了解甚少。在此，研究了在水培条件下，用50、100和200mg/L DFZ浓度处理根系时，DFZ的吸收、积累和转运以及形态、生理和基因表达的诱导变化。与对照相比，DFZ处理上调了参与木质素生物合成途径的4-香豆酸辅酶A连接酶（4CL）和过氧化物酶（POD）编码基因的表达，并增强了木质素生物合成。DFZ在老叶（子叶和下部真叶）中积累更多，分别比新的上部叶片和根中的含量高0.49 - 5.71倍和0.09 - 2.14倍。DFZ在组织中的过量积累迅速降解，从处理后3天到6天，根和叶中DFZ含量降低了15.7 - 69.3%。谷胱甘肽S-转移酶（GST）的基因表达和活性增加。此外，DFZ处理上调了参与类黄酮生物合成途径的查尔酮合酶（CHS）、查尔酮异构酶（CHI）和花青素合酶（ANS）编码基因的表达，并增加了叶片中类黄酮和花青素的含量。本研究为小麦植株在DFZ胁迫下表现出的自我保护行为提供了新的见解。其机制包括通过增强木质素生物合成来阻碍DFZ从根部渗透，在老叶中更多积累，通过GST降解，以及通过增加叶片中类黄酮和花青素的含量来减轻氧化损伤。
