Hunan Agricultural Biotechnology Research Institute, Hunan Academy of Agricultural Sciences, Changsha 410125, China; School of Minerals Processing and Bioengineering, Key Laboratory of Biometallurgy of Ministry of Education, Central South University, Changsha 410083, China.
School of Minerals Processing and Bioengineering, Key Laboratory of Biometallurgy of Ministry of Education, Central South University, Changsha 410083, China.
Ecotoxicol Environ Saf. 2022 Jan 1;229:113067. doi: 10.1016/j.ecoenv.2021.113067. Epub 2021 Dec 7.
The response of soil bacterial communities from farmland ecosystems to cadmium (Cd) pollution, in which a steep concentration gradient of more than 100 mg/kg has naturally formed, has not previously been fully reported. In this study, a field investigation was conducted in a typical severe Cd-polluted farmland ecosystem, and the bacterial community response to the steep Cd gradient was analyzed. The results showed that Cd concentration sharply decreased from 159.2 mg/kg to 4.18 mg/kg among four sampling sites alongside an irrigation canal over a distance of 150 m. Bacterial diversity and richness were significantly lower in highly polluted sites, and random forest analysis indicated that Cd gradient played a decisive role in reducing alpha diversity. Redundancy analysis (RDA) and co-occurrence network indicated that the synergistic effects of pH, Cd, and phosphorus were the main drivers shaping community structure. The functional results predicted by BugBase suggested that the bacterial community may adapt to the harsh environment by recruiting Cd-resistant microbes and improving oxidative stress tolerance of the whole community. Cd-resistant microorganisms such as Burkholderia, Bradyrhizobium, and Sulfurifustis, which directly or indirectly participate in diminishing oxidative damage of Cd, may play essential roles in maintaining community stability and might be potential bacterial resources for the bioremediation of Cd pollution.
农田生态系统土壤细菌群落对镉（Cd）污染的响应，其中自然形成了超过 100mg/kg 的陡峭浓度梯度，此前尚未得到充分报道。本研究在典型的重度 Cd 污染农田生态系统中进行了实地调查，分析了细菌群落对陡峭 Cd 梯度的响应。结果表明，在距离灌溉渠 150m 的四个采样点中，Cd 浓度从 159.2mg/kg 急剧下降到 4.18mg/kg。高污染点的细菌多样性和丰富度明显较低，随机森林分析表明 Cd 梯度对降低 alpha 多样性起着决定性作用。冗余分析（RDA）和共现网络分析表明，pH、Cd 和磷的协同作用是塑造群落结构的主要驱动因素。BugBase 预测的功能结果表明，细菌群落可能通过招募 Cd 抗性微生物和提高整个群落的氧化应激耐受性来适应恶劣环境。直接或间接参与减轻 Cd 氧化损伤的 Burkholderia、Bradyrhizobium 和 Sulfurifustis 等 Cd 抗性微生物，可能在维持群落稳定性方面发挥重要作用，并且可能是 Cd 污染生物修复的潜在细菌资源。
