Shen Shili, Li Yinghan, Chen Mingbiao, Huang Juan, Liu Feng, Xie Shijie, Kong Liping, Pan Ying
Institute for Ecological Research and Pollution Control of Plateau Lakes, School of Ecology and Environmental Science, Yunnan University, Kunming 650091, Yunnan, China; Yunnan Key Laboratory for Plateau Mountain Ecology and Restoration of Degraded Environments, School of Ecology and Environmental Sciences, Yunnan University, Kunming 650091, Yunnan, China; School of Ecology and Environmental Sciences, Yunnan University, Kunming 650091, Yunnan, China.
School of Ecology and Environmental Sciences, Yunnan University, Kunming 650091, Yunnan, China.
J Hazard Mater. 2023 May 5;449:131040. doi: 10.1016/j.jhazmat.2023.131040. Epub 2023 Feb 18.
Cd accumulation in crops has become a global environmental problem because it endangers human health. Screening for microorganisms that can reduce Cd accumulation in crops is a possible measure to address this issue. However, success has been limited, and most previous work did not involve bacteria. In the present study, a strain of N-fixing bacteria (Burkholderia spp.) that exhibits high levels of Cd tolerance was screened. The ability of this bacterium to reduce Cd in rapeseed was then assessed in sterile hydroponic and open soil culture systems. In the hydroponic system, the Burkholderia inoculum promoted Cd fixation in rapeseed roots and thus reduced Cd enrichment in aboveground edible tissues (leaves). The mechanisms were related to increased activity of pectin methylesterase in root cell walls, and the transformation of the chemical form of root Cd from "active" (NaCl-extracted) to "inert" (HCl-extracted and residual Cd) states. Additionally, Burkholderia accelerated plant growth, thus shortening the period in which the plant is available for Cd absorption. In the soil culture system, Burkholderia also reduced Cd enrichment in rapeseed leaves in the presence of other microorganisms. Thus, the bacterial strain shows potential for broad application for reducing the accumulation of Cd in crops.
作物中的镉积累已成为一个全球性的环境问题，因为它危及人类健康。筛选能够减少作物中镉积累的微生物是解决这一问题的一种可能措施。然而，成功案例有限，而且此前的大多数研究都未涉及细菌。在本研究中，筛选出了一种具有高镉耐受性的固氮细菌菌株（伯克霍尔德菌属）。然后在无菌水培和露天土壤培养系统中评估了这种细菌降低油菜中镉含量的能力。在水培系统中，伯克霍尔德菌接种物促进了镉在油菜根部的固定，从而减少了地上可食用组织（叶片）中的镉富集。其机制与根细胞壁中果胶甲酯酶活性增加以及根中镉的化学形态从“活性”（氯化钠提取）转变为“惰性”（盐酸提取和残留镉）状态有关。此外，伯克霍尔德菌促进了植物生长，从而缩短了植物吸收镉的时间。在土壤培养系统中，在存在其他微生物的情况下，伯克霍尔德菌也减少了油菜叶片中的镉富集。因此，该细菌菌株在减少作物中镉积累方面具有广泛应用的潜力。
