Key Laboratory of Pollution Exposure and Health Intervention Technology, Interdisciplinary Research Academy (IRA), Zhejiang Shuren University, Hangzhou 310015, China.
College of Environmental Science and Engineering, Zhejiang Gongshang University, Hangzhou 310018, China.
J Hazard Mater. 2022 Feb 15;424(Pt C):127638. doi: 10.1016/j.jhazmat.2021.127638. Epub 2021 Oct 30.
The enhanced heavy metal (HM) phytoextraction efficiency of hyperaccumulating plants via plant-growth-promoting microbes has been proposed as an effective strategy to remove HMs from contaminated soil. Nevertheless, it remains unclear whether catabolizing the abscisic acid (ABA) in hyperaccumulating plants via rhizobacteria can facilitate HM phytoextraction. In the present study, a hyperaccumulator, Sedum alfredii Hance, inoculated with an ABA-catabolizing bacterium Rhodococcus qingshengii, showed higher concentrations of Zn, Cd, Ni, and Pb in the contaminated paddy-grown plant shoots by 35%, 63%, 49%, and 49%, and in plants grown in mine soils by 112%, 105%, 46%, and 49%, respectively, than in the control plants. However, no significant changes were observed in Cu content between these plants. Furthermore, parameters indicating phytoremediation potential, including the translocation factor (TF) and bioconcentration factor (BCF), revealed that bacterial inoculation could markedly increase the efficacy of Zn, Cd, Ni, and Pb phytoextraction from the soil. Notably, the bioavailabilities of HMs in soils were not influenced by R. qingshengii; however, the expression of transporters related to the uptake of these HMs, including SaIRT1, SaZIP1, SaZIP2, SaZIP3, SaNramp1, SaNramp3, SaNramp6, SaHMA2, and SaHMA3, was upregulated. These findings indicate that R. qingshengii inoculation could increase the HM-uptake ability of plants by catabolizing ABA and may provide a promising strategy for enhancing the phytoremediation efficacy in HM-contaminated soils.
通过植物促生菌提高超积累植物对重金属的吸收效率，被认为是从污染土壤中去除重金属的有效策略。然而，通过根际细菌分解超积累植物中的脱落酸（ABA）是否能促进重金属的植物吸收，目前仍不清楚。在本研究中，用一种能分解 ABA 的 Rhodococcus qingshengii 菌接种超积累植物景天（Sedum alfredii Hance）后，发现其在受污染的稻田植物地上部分的锌、镉、镍和铅浓度分别提高了 35%、63%、49%和 49%，在矿区土壤中生长的植物浓度分别提高了 112%、105%、46%和 49%，而对照植物的铜浓度没有明显变化。此外，指示植物修复潜力的参数，包括迁移因子（TF）和生物浓缩因子（BCF），表明细菌接种可以显著提高从土壤中提取锌、镉、镍和铅的功效。值得注意的是，R. qingshengii 并没有影响土壤中重金属的生物有效性；然而，与这些重金属吸收有关的转运蛋白的表达，包括 SaIRT1、SaZIP1、SaZIP2、SaZIP3、SaNramp1、SaNramp3、SaNramp6、SaHMA2 和 SaHMA3，被上调。这些发现表明，R. qingshengii 接种可以通过分解 ABA 来提高植物对重金属的吸收能力，为提高重金属污染土壤的植物修复效果提供了一种有前景的策略。
