State Key Laboratory of Herbage Improvement and Grassland Agro-ecosystems, Center for Grassland Microbiome, College of Pastoral Agriculture Science and Technology, Lanzhou University, Lanzhou, 730000, China.
College of biological and Geographical Sciences, Yili Normal University, Yining, 835000, China.
Environ Pollut. 2024 Feb 1;342:123040. doi: 10.1016/j.envpol.2023.123040. Epub 2023 Nov 26.
Cadmium (Cd) pollution is one of the most severe toxic metals pollution in grassland. Vicia unijuga (V. unijuga) A.Br. planted nearby the grassland farming are facing the risk of high Cd contamination. Here, we investigated the beneficial effects of a highly Cd tolerant rhizosphere bacterium, Cupriavidus sp. WS2, on Cd contaminated V. unijuga. Through plot experiments, we set up four groups of treatments: the control group (without WS2 or Cd), the Cd group (with only Cd addition), the WS2 group (with only WS2 addition), and the WS2/Cd group (with WS2 and Cd addition), and analyzed the changes in physiological indicators, rhizosphere microorganisms, and stem and leaf metabolites of V. unijuga. Results of physiological indicators indicated that Cupriavidus sp. WS2 had strong absorption and accumulation capacity of Cd, exogenous addition of strain WS2 remarkably decreased the Cd concentrations, and increased the plant heights, the biomass, the total protein concentrations, the chlorophyll contents and the photosynthetic rate in stems and leaves of V. unijuga under Cd stress. Cd treatment increased the abundance of Cd tolerant bacterial genera in rhizosphere microbiome, but these genera were down-regulated in the WS2/Cd group. Pseudotargeted metabolomic results showed that six common differential metabolites associated with antioxidant stress were increased after co-culture with WS2. In addition, WS2 activated the antioxidant system including glutathione (GSH) and catalase (CAT), reduced the contents of oxidative stress markers including malondialdehyde (MDA) and hydrogen peroxide (HO) in V. unijuga under Cd stress. Taken together, this study revealed that Cupriavidus sp.WS2 alleviated the toxicity of V. unijuga under Cd exposure by activating the antioxidant system, increasing the antioxidant metabolites, and reducing the oxidative stress markers.
镉（Cd）污染是草原最严重的有毒金属污染之一。种植在草原农田附近的百脉根（Vicia unijuga）面临着高镉污染的风险。在这里，我们研究了一种高镉耐受根际细菌，铜绿假单胞菌 WS2，对 Cd 污染百脉根的有益作用。通过田间试验，我们设置了四组处理：对照组（无 WS2 或 Cd）、Cd 组（仅添加 Cd）、WS2 组（仅添加 WS2）和 WS2/Cd 组（添加 WS2 和 Cd），并分析了百脉根生理指标、根际微生物和茎叶代谢物的变化。生理指标的结果表明，铜绿假单胞菌 WS2 对 Cd 具有很强的吸收和积累能力，外源性添加菌株 WS2 显著降低了 Cd 浓度，增加了 Cd 胁迫下百脉根的株高、生物量、总蛋白浓度、叶绿素含量和叶片光合速率。Cd 处理增加了根际微生物群落中 Cd 耐受细菌属的丰度，但这些属在 WS2/Cd 组中下调。拟靶向代谢组学结果表明，与抗氧化应激相关的 6 种常见差异代谢物在与 WS2 共培养后增加。此外，WS2 激活了抗氧化系统，包括谷胱甘肽（GSH）和过氧化氢酶（CAT），降低了 Cd 胁迫下百脉根中氧化应激标志物丙二醛（MDA）和过氧化氢（HO）的含量。总之，本研究表明，铜绿假单胞菌 WS2 通过激活抗氧化系统、增加抗氧化代谢物和降低氧化应激标志物，减轻了 Cd 暴露下百脉根的毒性。
