Plant Stress and Molecular Biology Laboratory, Department of Botany, University of Kalyani, Kalyani, 741235, West Bengal, India.
Plant Stress and Molecular Biology Laboratory, Department of Botany, University of Kalyani, Kalyani, 741235, West Bengal, India.
Chemosphere. 2022 Jan;287(Pt 1):131911. doi: 10.1016/j.chemosphere.2021.131911. Epub 2021 Aug 20.
The present study aimed to systematically investigate the particle size effects of copper (II) oxide [CuO nanoparticles (<50 nm) and CuO bulk particles (<10 μm)] on maize (Zea mays L.). Bioaccumulation of Cu, in vivo ROS generation, membrane damage, transcriptional modulation of antioxidant genes, cellular redox status of glutathione and ascorbate pool, expression patterns of COPPER TRANSPORTER 4 and stress responsive miRNAs (miR398a, miR171b, miR159f-3p) with their targets were investigated for better understanding of the underlying mechanisms and the extent of CuO nanoparticles and CuO bulk particles induced oxidative stress damages. More restricted seedling growth, comparatively higher membrane injury, marked decline in the levels of chlorophylls and carotenoids and severe oxidative burst were evident in CuO bulk particles challenged leaves. Dihydroethidium and CM-H2DCFDA staining further supported elevated reactive oxygen species generation in CuO bulk particles stressed roots. CuO bulk particles exposed seedlings accumulated much higher amount of Cu in roots as compared to CuO nanoparticles stressed plants with low root-to-shoot Cu translocation. Moderately high GR expression with maintenance of a steady GSH-GSSG ratio in CuO nanoparticles challenged leaves might be accountable for their rather improved performance under stressed condition. miR171b-mediated enhanced expression of SCARECROW 6 might participate in the marked decline of chlorophyll content in CuO bulk particles exposed leaves. Ineffective recycling of AsA pool is another decisive feature of inadequate performance of CuO bulk particles stressed seedlings in combating oxidative stress damages. Taken together, our findings revealed that toxicity of CuO bulk particles was higher than CuO nanoparticles and the adverse effects of CuO bulk particles on maize seedlings might be due to higher Cu ions dissolution.
本研究旨在系统研究氧化铜（CuO 纳米颗粒（<50nm）和 CuO 体相颗粒（<10μm））的粒径效应对玉米（Zea mays L.）的影响。研究了 Cu 的生物累积、体内 ROS 生成、膜损伤、抗氧化基因的转录调控、谷胱甘肽和抗坏血酸池的细胞氧化还原状态、铜转运蛋白 4 的表达模式以及应激响应 miRNA（miR398a、miR171b、miR159f-3p）及其靶基因，以更好地理解其潜在机制以及 CuO 纳米颗粒和 CuO 体相颗粒诱导的氧化应激损伤的程度。在受到 CuO 体相颗粒挑战的叶片中，幼苗生长受到更严重的限制，相对较高的膜损伤，叶绿素和类胡萝卜素水平显著下降，以及严重的氧化爆发。二氢乙啶和 CM-H2DCFDA 染色进一步支持在受到 CuO 体相颗粒胁迫的根部中活性氧物种的产生增加。与受到 CuO 纳米颗粒胁迫的植物相比，暴露于 CuO 体相颗粒的幼苗在根部积累了更多的 Cu，根到茎的 Cu 转运较低。在受到 CuO 纳米颗粒挑战的叶片中，GR 表达适度升高，GSH-GSSG 比值保持稳定，这可能是它们在胁迫条件下表现更好的原因。miR171b 介导的 SCARECROW 6 表达增强可能参与了 CuO 体相颗粒暴露叶片中叶绿素含量的显著下降。AsA 池的无效循环是 CuO 体相颗粒胁迫幼苗在对抗氧化应激损伤方面表现不佳的另一个决定性特征。综上所述，我们的研究结果表明，CuO 体相颗粒的毒性高于 CuO 纳米颗粒，CuO 体相颗粒对玉米幼苗的不良影响可能是由于较高的 Cu 离子溶解。
