鄱阳湖-乐安河段湿地耐Cu、Zn、Pb植物促生菌的分离、筛选及鉴定

Isolation, screening and identification of Cu, Zn and Pb resistant plant growth-promoting bacteria from Le’an River-Poyang Lake Wetland

摘要:

【背景】植物促生菌因其对植物生长促进及增强抗逆性等优点在植物-微生物联合修复重金属污染土壤中具有良好应用潜力。在污染土壤中，土著植物促生菌能够更好地定殖并保证促植物生长能力的发挥。【目的】从常年受上游多种重金属污染的鄱阳湖-乐安河段湿地分离出一批具有多种重金属抗性的优势土著植物促生菌，以期为植物-微生物联合修复重金属污染湿地提供一批优质的菌种资源。【方法】从乐安河流域戴村受重金属污染的湿地土壤及水体中分离具有Cu、Zn、Pb抗性菌株，测定菌株的促植物生长特性[产IAA (Indole acetic acid)、溶磷、产铁载体及ACC (1-aminocyclopropane-1-carboxylic acid)脱氨酶活性]，挑选促生特性较好的菌株进行16S rRNA基因序列分析鉴定，并测定菌株对其他胁迫条件(抗生素、酸碱、盐)的耐受能力。【结果】分离得到22株能够同时耐受Cu 50 mg/L、Zn 400 mg/L、Pb 800 mg/L的菌株，其中10株表现出较好的促植物生长特性，对其进行16S rRNA基因序列分析鉴定，有4株属于Ralstonia sp.，3株属于Burkholderia sp.，另3株则分别属于Cupriavidus sp.、Stenotrophomonas sp.和Novosphingobium sp.。基于这10株菌抗性特征的聚类分析及主成分分析，结果与系统发育树分析结果高度一致。【结论】耐受多种重金属的土著植物促生菌的分离鉴定为重金属污染土壤的植物-微生物联合原位修复提供良好的微生物资源。

Abstract:

[Background] Plant growth-promoting bacteria (PGPB) have good potential in assisting phytoremediation of heavy metal pollution due to their advantages in promoting the growth and heavy metal-resistance of plants. In heavy metal-contaminated soils, indigenous PGPB can better colonize and exert their plant growth-promoting abilities. [Objective] Our aim is to isolate the indigenous heavy mental-resistant PGPB from the Le’an River-Poyang Lake Wetland, which has been polluted by acid mine drainage for many years, thus to provide superior microbial resources for bacterial assisted phytoremediation of heavy metal polluted wetland soil. [Methods] Cu, Zn and Pb-resistant strains were isolated from heavy metal polluted wetland soils and water in Dai cun, which is located in Le’an River. The plant growth-promoting characteristics (IAA (Indole acetic acid), phosphate solubilization, siderophore and ACC (1-aminocyclopropane-1-carboxylic acid) deaminase activity) of the studied isolates were measured, and the isolates with good growth-promoting characteristics were selected and identified using 16S rRNA gene sequencing. The resistant characteristics (heavy metal, antibiotics, acid and alkali, salt) of the selected strains were also determined. [Results] A total of 22 isolates were able to grow in the presence of Cu 50 mg/L, Zn 400?mg/L and Pb 800 mg/L. Among them, 10 strains showed good plant growth-promoting characteristics. According to 16S rRNA gene sequencing, 4 strains belonged to the genus Ralstonia, 3 strains belonging to the genus Burkholderia and the other 3 strains belonged to the genera Cupriavidus, Stenotrophomonas and Novosphingobium, repectively. The numerical classification based on bacterial resistant characteristics was mostly consistent with their phylogenetic position. [Conclusion] The isolation and identification of multiple heavy mental-resistant PGPB could provide good microbial resources for in situ remediation of heavy metal contaminated soils.