GreenUPorto - Sustainable Agrifood Production Research Centre, Biology Department, Faculty of Sciences, University of Porto, Rua do Campo Alegre s/n, 4169-007, Porto, Portugal.
Departamento de Biologia, Faculdade de Ciências, Universidade do Porto, Rua Campo Alegre s/n, 4169-007, Porto, Portugal.
Environ Sci Pollut Res Int. 2020 Aug;27(23):29130-29142. doi: 10.1007/s11356-020-09136-x. Epub 2020 May 19.
The continuous increase of the human population worldwide has led to an increase of pharmaceuticals' consumption, such as diclofenac (DCF), a widely used non-steroidal anti-inflammatory drug (NSAID), that is not removed by wastewater treatment processes. Although there is some research regarding the effects of DCF on animals and aquatic invertebrates, information concerning its influence on plants' metabolism is still scarce. Through an integrated approach, using combined biochemical and molecular biology techniques, this work aimed to evaluate the phytotoxicity of DCF in Solanum lycopersicum L., focusing on the primary plant processes: nitrogen (N) assimilation and photosynthesis. The exposure of tomato plants to increasing concentrations of DCF (0, 0.5, and 5 mg L) revealed that glutamine synthetase (GS) was differentially affected, in an organ-dependent manner, by this contaminant at the gene expression, protein, and activity levels, with an increased activity of 0.2-fold in shoots of plants treated with the lowest concentration of DCF although a general decrease was registered for the SlGS gene family expression, revealing that post-translational regulation was in order, since GS2 polypeptide content did not change. Glutamate dehydrogenase (GDH) activity was generally enhanced, accompanied by increases of 0.4- to 1.9-fold in proline levels, revealing GDH as an important compensatory route for both N assimilation and proline production under stressful conditions. No alterations in most photosynthetic endpoints were noticed after DCF treatments, but small decreases of 0.1- to 0.8-fold in the accumulation of RuBisCO-encoding transcripts were observed, along with a reduction in starch content. Some alterations in the soluble polypeptide profile were also detected in response to DCF, evidencing the participation of some stress-related proteins in the plant's response to DCF.
全球人口的持续增长导致了药品（如双氯芬酸 (DCF)）消费的增加，DCF 是一种广泛使用的非甾体抗炎药 (NSAID)，但它不能被废水处理过程去除。尽管已经有一些关于 DCF 对动物和水生无脊椎动物影响的研究，但关于它对植物代谢影响的信息仍然很少。本研究采用综合生化和分子生物学技术，旨在评估 DCF 对番茄（Solanum lycopersicum L.）的植物毒性，重点关注植物的氮同化和光合作用等初级生理过程。通过向番茄植株施加不同浓度（0、0.5 和 5mg/L）的 DCF，结果表明，谷氨酰胺合成酶（GS）在器官依赖的方式下受到该污染物的不同影响，表现在基因表达、蛋白质和活性水平上。与对照组相比，最低浓度的 DCF 处理组的植株茎部 GS 活性增加了 20%，但 SlGS 基因家族的表达普遍下降，表明可能存在翻译后调控，因为 GS2 多肽的含量没有变化。谷氨酸脱氢酶（GDH）活性普遍增强，脯氨酸水平升高 0.4-1.9 倍，表明在胁迫条件下，GDH 是氮同化和脯氨酸合成的重要补偿途径。DCF 处理后，大多数光合作用终点没有发生变化，但 RuBisCO 编码转录物的积累减少了 0.1-0.8 倍，淀粉含量减少。此外，还观察到可溶性多肽谱的一些变化，表明一些与应激相关的蛋白质参与了植物对 DCF 的响应。
