Colonized extremophile Deinococcus radiodurans alleviates toxicity of cadmium and lead by suppressing heavy metal accumulation and improving antioxidant system in rice
Colonized extremophile Deinococcus radiodurans alleviates toxicity of cadmium and lead by suppressing heavy metal accumulation and improving antioxidant system in rice
复制标题
定植的极端微生物耐辐射奇球菌通过抑制重金属积累和改善水稻抗氧化系统来减轻镉和铅的毒性
DOI：
10.1016/j.envpol.2021.117127
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发表时间：
2021-04-20
影响因子：
8.9
通讯作者：
Tian, Bing
中科院分区：
文献类型：
--
作者：
Dai, Shang;Chen, Qi;Tian, Bing
镉（Cd）和铅（Pb）是水稻中积累的主要有毒重金属，对人类健康构成严重威胁。最重要的修复策略是减少这些重金属从污染土壤到水稻的迁移。利用微生物进行生物修复已被广泛应用于环境重金属污染的防治，微生物与植物的相互作用是减轻重金属胁迫的关键。本研究证明了一株耐辐射异常球菌（Deinococcus radiodurans），特别是其突变株Ddr2577，其细胞表层缺陷能有效地防止Cd、Pb在水稻中的迁移和伤害。细菌细胞能有效地去除培养基中的Cd或Pb。Ddr2577细胞在水稻根中定殖后，根中Cd含量和地上部Cd含量分别比单独Cd处理降低71.6%和60.9%，根中Pb含量和地上部Pb含量分别比单独Pb处理降低73.3%和56.9%。同时，细菌细胞释放其细胞内的抗氧化相关分子，包括谷氨酸和锰离子到培养基中。积累的谷氨酸和锰离子在水稻根和地上部检测到改善镉/铅诱导的氧化胁迫，表明在水稻中的ROS水平降低和抗氧化酶的活性增强。研究结果为极端嗜热菌在减轻水稻重金属毒害方面的应用提供了可能。主要研究结果揭示了D.耐辐射菌与水稻的关系，以及极端嗜热菌通过抑制重金属积累和改善水稻抗氧化系统来缓解镉、铅毒害的机制。(c)2021爱思唯尔有限公司版权所有。
Cadmium (Cd) and lead (Pb) are the major toxic heavy metals accumulated in rice and pose a serious threat to human health. The most important remediation strategy is to reduce the translocation of these heavy metals from polluted soil to rice. Bioremediation using microorganisms had been widely used for preventing environmental heavy metal pollution, and the interaction between microorganisms and plants is critical to reduce the heavy metal stress. In this study, we demonstrated that an extremophile Deinococcus radiodurans, especially its mutant strain-Ddr2577 which is deficient in cell surface-layer, could efficiently prevent the translocation and damages of Cd or Pb in rice. The bacterial cells effi-ciently removed Cd or Pb from culture medium. Following colonization of Ddr2577 cells in rice root, Cd level decreased to 71.6% in root and 60.9% in shoot, comparing to the plants treated with Cd alone; Pb level decreased to 73.3% in root and 56.9% in shoot, comparing to the plants treated with Pb alone. Meanwhile, the bacterial cells released their intracellular antioxidant-related molecules including glutamate and manganese ions into culture medium. Accumulation of glutamate and manganese ions detected in rice root and shoot ameliorate Cd/Pb-induced oxidative stress as indicated by reduced levels of ROS and enhanced activities of antioxidant enzymes in rice. Our results provide a potential application of an extremophile bacterium in alleviating heavy metal toxicity in rice. The main findings of the work reveal the interaction between the D. radiodurans and rice, as well as the alleviating mechanism of Cd and Pb toxicity through suppressing heavy metal accumulation and improving the antioxidant system in rice by the extremophile bacterium. (c) 2021 Elsevier Ltd. All rights reserved.