Ge Yanyan, Wen Zhenyu, Liu Xuan, Xiong Zhihui, Sheng Xiafang
College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, China.
College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, China.
J Environ Sci (China). 2025 Nov;157:52-64. doi: 10.1016/j.jes.2024.12.023. Epub 2024 Dec 26.
The Cd-tolerant and sodium alginate (SA)-synthesizing Pseudomonas putida XMS-1 was characterized for Cd immobilization in solution. Additionally, the XMS-1 mutant constructed by deleting SA-synthesizing regulatory gene algB (∆algB) were characterized for their roles in Cd uptake in Chinese chive in the Cd-contaminated soil. Between 12 and 48 h of incubation, the XMS-1∆algB mutant significantly reduced solution Cd concentrations by 81 % compared with the control but increased the Cd concentrations by 36 % compared with XMS-1. After 48 h of incubation, the XMS-1∆algB mutant significantly increased the Cd concentration by 36 % and decreased the expolysaccharide (EPS) and SA concentrations by 30 %-32 % and cell surface-adsorbed Cd content by 24 % in the Cd-containing medium, compared with XMS-1. The XMS-1∆algB mutant significantly increased the root and leaf Cd contents of Chinese chive by 15 %-50 % and exchangeable Cd content by 17 % and decreased the Fe-Mn oxide- and organic matter-bound Cd contents by 17 %-23 %, compared with XMS-1. Furthermore, the XMS-1∆algB mutant significantly decreased the EPS content by 33 %, copies of algD gene involved in EPS production by 7.7-fold, and the interactions between the amino, hydroxyl, and carbonyl groups and Cd in the Cd-contaminated soil, compared with XMS-1. These results suggested that algB promoted XMS-1-mediated Cd-stabilizing related gene abundance and interactions between soil and Cd and decreased Cd uptake in Chinese chive. These findings may provide an effective and eco-friendly way using SA-producing bacteria for safe production of vegetables in the Cd-polluted soil.
耐镉且能合成海藻酸钠（SA）的恶臭假单胞菌XMS-1被用于研究其在溶液中固定镉的特性。此外，通过缺失合成SA的调控基因algB构建的XMS-1突变体（∆algB），被用于研究其在镉污染土壤中韭菜吸收镉过程中的作用。在培养12至48小时之间，与对照相比，XMS-1∆algB突变体使溶液中镉浓度显著降低了81%，但与XMS-1相比，镉浓度增加了36%。培养48小时后，与XMS-1相比，XMS-1∆algB突变体在含镉培养基中使镉浓度显著增加了36%，胞外多糖（EPS）和SA浓度降低了30%-32%，细胞表面吸附的镉含量降低了24%。与XMS-1相比，XMS-1∆algB突变体使韭菜的根和叶镉含量显著增加了15%-50%，可交换镉含量增加了17%，铁锰氧化物结合态和有机质结合态镉含量降低了17%-23%。此外，与XMS-1相比，XMS-1∆algB突变体使EPS含量显著降低了33%，参与EPS产生的algD基因拷贝数降低了7.7倍，且在镉污染土壤中氨基、羟基和羰基与镉之间的相互作用减弱。这些结果表明，algB促进了XMS-1介导的与镉稳定相关基因的丰度以及土壤与镉之间的相互作用，并降低了韭菜对镉的吸收。这些发现可能为利用产SA细菌在镉污染土壤中安全生产蔬菜提供一种有效且环保的方法。
