水稻根内生菌Bacillus sp.RE35耐受及累积吸附Cd的机制  

The mechanisms of tolerance,accumulation and adsorption of Cd by rice roots endophyte Bacillus sp.RE35

作　　者：王博 黄琴 石美侠 史高玲 卢信[2,3] 陈未 高岩 Bo Wang;Qin Huang;Meixia Shi;Gaoling Shi;Xin Lu;Wei Chen;Yan Gao(School of the Environment and Safety Engineering,Jiangsu University,Zhenjiang 212013,China;Institute of Agricultural Resources and Environment,Jiangsu Academy of Agricultural Sciences,Nanjing 210014,China;Key Laboratory of Agro-Environment in Downstream of Yangtze Plain,Ministry of Agriculture and Rural Affairs,Nanjing 210014,China;College of Resources and Environmental Sciences,Nanjing Agricultural University,Nanjing 210095,China)

机构地区：[1]江苏大学环境与安全工程学院,镇江212013 [2]江苏省农业科学院农业资源与环境研究所,南京210014 [3]农业农村部长江下游平原农业环境重点实验室,南京210014 [4]南京农业大学资源与环境科学学院,南京210095

出　　处：《科学通报》2024年第7期950-964,共15页Chinese Science Bulletin

基　　金：江苏省农业科技自主创新资金(CX(20)1010);国家自然科学基金(42107028)资助。

摘　　要：水稻对镉(Cd)的高富集能力会引发人体健康风险.利用内生菌降低水稻根系Cd移动性的研究已被广泛关注,但具有高Cd耐受性的水稻内生菌资源尚待发掘,其对不同浓度Cd的耐受和累积吸附机制也有待深入研究.本研究基于前期筛选出的高Cd耐受性水稻根内生菌Bacillus sp.RE35,通过液体培养实验研究其对Cd的耐受和累积吸附机制.结果表明,菌株RE35对Cd的最大耐受浓度可达600 mg/L,最大吸附容量为28.49 mg/g,对1和5 mg/L Cd^(2+)的去除率可达88.4%和80.4%.当Cd浓度低于20 mg/L时,菌株RE35对Cd^(2+)的去除以胞内累积为主,随着Cd浓度升高,菌株三磷酸腺苷酶活性显著增强,透射电子显微镜和X射线能谱结果显示Cd均匀地分布于菌株细胞内.当Cd浓度高于20 mg/L时,胞外吸附对Cd^(2+)的去除具有重要作用,其分泌的胞外聚合物中蛋白质组分增加.X射线光电子能谱和傅里叶变换红外吸收光谱结果显示,菌株胞外蛋白质的氨基和酰胺等基团与Cd的吸附密切相关.本研究阐明了高Cd耐受性内生菌RE35对不同浓度Cd的累积吸附机制,为内生菌菌剂开发提供了宝贵的菌种资源信息.The cadmium(Cd)contamination in agricultural land has been attracting much attention worldwide due to its potential health risks.Rice grown in the polluted field may pose a serious threat to human health through dietary intake because its high Cd enrichment ability leads to Cd accumulation in the grain.It has been shown that plant endophytes have the ability to immobilize Cd,but there are few studies reporting the characteristics of rice endophytes with high Cd tolerance,and their Cd-immobilizing mechanisms under different concentrations of Cd need further studies.In this article,a liquid adsorption test was conducted to investigate the Cd tolerance and immobilizing mechanisms of the rice root endophyte Bacillus sp.RE35 that was previously screened for high Cd tolerance.The results showed that the maximum Cd tolerance concentration of strain RE35 could reach 600 mg/L,the maximum adsorption capacity was 28.49 mg/g,and the removal rates of 1 and 5 mg/L Cd^(2+)were 88.37%and 80.40%,respectively.The stain can tolerate such high concentrations of Cd equivalent to the stains isolated from Cd-contaminated soil.The strain RE35 showed distinct Cd accumulation and adsorption mechanisms at different Cd concentrations.When Cd concentration was lower than 20 mg/L,Cd^(2+)removal by strain RE35 was dominated by intracellular accumulation.The production of siderophores,as a possible transport carrier of Cd,was greatly reduced under Cd treatment,indicating that siderophores did not have significant contribution to the intracellular accumulation of Cd by the strain RE35.The determination of ATPase activities showed that they increased significantly with the increase of Cd concentrations,and it was speculated that the intracellular transport of Cd by strain RE35 may be related to ATP-dependent metal transporters.The distribution of Cd inside strain RE35 cells was investigated by high-resolution transmission electron microscopy and energy dispersive spectroscopy,and the results revealed that Cd was uniformly distributed in the cytop

关 键 词：水稻内生菌 镉耐受性 胞内累积 胞外吸附 芽孢杆菌 

分 类 号：X17[环境科学与工程—环境科学]