State Key Laboratory of Pollution Control and Resource Reuse, School of Environment, Nanjing University, Nanjing, Jiangsu, 210023, China.
Crop Science Institute, National Agricultural Research Centre (NARC), Islamabad, Pakistan.
Chemosphere. 2024 Sep;364:143113. doi: 10.1016/j.chemosphere.2024.143113. Epub 2024 Aug 14.
Cadmium (Cd) contamination in agricultural soil is a major global concern among the multitude of human health and food security. Zinc oxide nanoparticles (ZnO-NPs) and plant growth promoting rhizobacteria (PGPR) have been known to combat heavy metal toxicity in crops. Herein, the study intended to explore the interactive effect of treatments mediated by inoculation of PGPR and foliar applied ZnO-NPs to alleviate Cd induced phytotoxicity in wheat plants which is rarely investigated. For this purpose, TaEIL1 expression, morpho-physiological, and biochemical traits of wheat were examined. Our results revealed that Cd reduced growth and biomass, disrupted plant physiological and biochemical traits, and further expression patterns of TaEIL1. The foliar application of ZnO-NPs improved growth attributes, photosynthetic pigments, and gas exchange parameters in a dose-additive manner, and this effect was further amplified with a combination of PGPR. The combined application of ZnO-NPs (100 mg L-1) with PGPR considerably increased the catalase (CAT; 52.4%), peroxidase (POD; 57.4%), superoxide dismutase (SOD; 60.1%), ascorbate peroxidase (APX; 47.4%), leading to decreased malondialdehyde (MDA; 47.4%), hydrogen peroxide (H2O2; 38.2%) and electrolyte leakage (EL; 47.3%) under high Cd (20 mg kg-1) stress. Furthermore, results revealed a significant reduction in roots (56.3%), shoots (49.4%), and grains (59.4%) Cd concentration after the Combined treatment of ZnO-NPs and PGPR as compared to the control. Relative expression of TaEIL1 (two homologues) was evaluated under control (Cd 0), Cd, ZnO-NPs, PGPR, and combined treatments. Expression profiling revealed a differential expression pattern of TaEIL1 under different treatments. The expression pattern of TaEIL1 genes was upregulated under Cd stress but downregulated under combined ZnO-NPs and PGPR, revealing its crucial role in Cd stress tolerance. Inferentially, ZnO-NPs and PGPR showed significant potential to alleviate Cd toxicity in wheat by modulating the antioxidant defense system and TaEIL1 expression. By inhibiting Cd uptake, and facilitating their detoxification, this innovative approach ensures food safety and security.
镉（Cd）污染是农业土壤中一个主要的全球性问题，对人类健康和粮食安全造成了多方面的影响。氧化锌纳米粒子（ZnO-NPs）和植物促生根际细菌（PGPR）已被证明可以减轻作物的重金属毒性。在此，本研究旨在探索通过接种 PGPR 和叶面喷施 ZnO-NPs 来减轻 Cd 诱导的小麦植物毒性的处理的相互作用，这在很少被研究。为此，我们研究了 TaEIL1 的表达、形态生理和生化特性。我们的结果表明，Cd 降低了小麦的生长和生物量，破坏了植物的生理生化特性，进一步影响了 TaEIL1 的表达模式。叶面喷施 ZnO-NPs 以剂量累加的方式改善了生长指标、光合色素和气体交换参数，而与 PGPR 联合使用则进一步放大了这种效果。ZnO-NPs（100mg L-1）与 PGPR 的联合应用显著增加了过氧化氢酶（CAT；52.4%）、过氧化物酶（POD；57.4%）、超氧化物歧化酶（SOD；60.1%）、抗坏血酸过氧化物酶（APX；47.4%）的活性，导致丙二醛（MDA；47.4%）、过氧化氢（H2O2；38.2%）和电解质渗漏（EL；47.3%）的减少在高 Cd（20mg kg-1）胁迫下。此外，与对照相比，ZnO-NPs 和 PGPR 联合处理后，根（56.3%）、茎（49.4%）和籽粒（59.4%）中的 Cd 浓度显著降低。在对照（Cd 0）、Cd、ZnO-NPs、PGPR 和联合处理下，评估了 TaEIL1（两个同源物）的相对表达。表达谱分析显示，TaEIL1 在不同处理下的表达模式存在差异。在 Cd 胁迫下，TaEIL1 基因的表达模式上调，但在 ZnO-NPs 和 PGPR 联合处理下下调，表明其在 Cd 胁迫耐受中具有重要作用。推断，ZnO-NPs 和 PGPR 通过调节抗氧化防御系统和 TaEIL1 的表达，显示出减轻小麦 Cd 毒性的显著潜力。通过抑制 Cd 的吸收和促进其解毒，这种创新方法确保了食品安全。
