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. 2020 Jun;249:126197. doi: 10.1016/j.chemosphere.2020.126197. Epub 2020 Feb 12.
Rapid expansion of nanotechnology and indiscriminate discharge of metal oxide nanoparticles (NPs) into the environment pose a serious hazard to the ecological receptors including plants. To better understand the role of miRNAs in ZnO-NPs stress adaptation, two small RNA libraries were prepared from control and ZnO-NPs (800 ppm, <50 nm particle size) stressed maize leaves. Meager performance of ZnO-NPs treated seedlings was associated with elevated tissue zinc accumulation, enhanced ROS generation, loss of root cell viability, increased foliar MDA content, decrease in chlorophyll and carotenoids contents. Deep sequencing identified 3 (2 known and 1 novel) up- and 77 (73 known and 4 novel) down-regulated miRNAs from ZnO-NPs challenged leaves. GO analysis reveals that potential targets of ZnO-NPs responsive miRNAs regulate diverse biological processes viz. plant growth and development (miR159f-3p, zma_18), ROS homeostasis (miR156b, miR166l), heavy metal transport and detoxification (miR444a, miR167c-3p), photosynthesis (miR171b) etc. Up-regulation of SCARECROW 6 in ZnO-NPs treated leaves might be responsible for suppression of chlorophyll biosynthesis leading to yellowing of leaves. miR156b.1 mediated up-regulation of CALLOSE SYNTHASE also does not give much protection against ZnO-NPs treatment. Taken together, the findings shed light on the miRNA-guided stress regulatory networks involved in plant adaptive responses to ZnO-NPs stress.
纳米技术的迅速发展和金属氧化物纳米粒子（NPs）的无差别排放对包括植物在内的生态受体构成了严重威胁。为了更好地理解 miRNAs 在 ZnO-NPs 胁迫适应中的作用，我们从对照和 ZnO-NPs（800 ppm，<50nm 粒径）胁迫的玉米叶片中分别制备了两个小 RNA 文库。ZnO-NPs 处理的幼苗表现不佳，与组织中锌积累增加、ROS 生成增强、根细胞活力丧失、叶片 MDA 含量增加、叶绿素和类胡萝卜素含量降低有关。深度测序从 ZnO-NPs 处理的叶片中鉴定出 3 个（2 个已知和 1 个新）上调和 77 个（73 个已知和 4 个新）下调的 miRNAs。GO 分析表明，ZnO-NPs 响应 miRNAs 的潜在靶标调节多种生物过程，如植物生长和发育（miR159f-3p、zma_18）、ROS 稳态（miR156b、miR166l）、重金属转运和解毒（miR444a、miR167c-3p）、光合作用（miR171b）等。在 ZnO-NPs 处理的叶片中，SCARECROW6 的上调可能是导致叶绿素生物合成受到抑制导致叶片变黄的原因。miR156b.1 介导的 CALLOSE SYNTHASE 上调也不能为 ZnO-NPs 处理提供太多保护。总之，这些发现揭示了 miRNA 指导的植物适应 ZnO-NPs 胁迫的应激调节网络。
