State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, 430070, China.
Key Laboratory of Arable Land Conservation (Middle and Lower Reaches of Yangtze River), Ministry of Agriculture, College of Resources and Environment, Huazhong Agricultural University, Wuhan, China.
Appl Microbiol Biotechnol. 2019 May;103(9):3887-3897. doi: 10.1007/s00253-019-09700-7. Epub 2019 Feb 28.
Heavy metal pollution in agricultural soils has become a widespread serious problem with the rapid industrialization and urbanization in the past two decades. Cadmium (Cd) is of the most concern in soils due to its high toxicity. It is necessary to develop remediation strategies to remove or neutralize its toxic effects in Cd-contaminated soil. Microbial bioremediation is a promising technology to treat heavy metal-contaminated soils. In this study, Cd-resistant bacterium, isolated from heavy metal-polluted soil in Southern China, was characterized as Raoultella sp. strain X13 on the basis of its biochemical profile and 16S rRNA. We investigated the characterization of Cd distribution in different cellular compartments after Cd uptake. Cd uptake by strain X13 was mainly by ion exchange and chelation binding tightly to the cell wall. In addition, X13 plant growth-promoting characteristics suggested that X13 could solubilize phosphate and produce indole acetic acid. Pot experiments for the remediation of Cd-contaminated soil in situ by X13 inoculation demonstrated that X13 application to Cd-contaminated soils significantly promoted pak choi growth and improved production. We also found that X13 substantially reduced the Cd bioavailability for pak choi. Therefore, strain X13 is an effective treatment for potential application in Cd remediation as well as for sustainable agronomic production programs in Cd-contaminated soils.
在过去的二十年中，随着工业化和城市化的快速发展，农业土壤中的重金属污染已成为一个普遍而严重的问题。由于镉（Cd）的高毒性，它在土壤中是最受关注的。因此，有必要开发修复策略来消除或中和受 Cd 污染土壤中的毒性。微生物生物修复是一种很有前途的技术，可用于处理重金属污染的土壤。在这项研究中，根据其生化特征和 16S rRNA，从中国南方重金属污染土壤中分离出的 Cd 抗性细菌被鉴定为罗尔氏菌属 X13 菌株。我们研究了 Cd 在细胞不同隔室中的分布特征，以了解 Cd 的吸收情况。X13 菌株对 Cd 的摄取主要通过离子交换和螯合作用与细胞壁紧密结合。此外，X13 还具有促进植物生长的特性，表明其可以溶解磷酸盐并产生吲哚乙酸。通过 X13 接种原位修复 Cd 污染土壤的盆栽实验表明，X13 的应用显著促进了白菜的生长并提高了产量。我们还发现，X13 显著降低了 Cd 对白菜的生物有效性。因此，该菌株是一种有效的处理方法，有望应用于 Cd 修复以及受 Cd 污染土壤的可持续农业生产计划。
