万顺铅锌矿区蜈蚣草内生细菌砷氧化基因(aoxB)的多样性分析

Diversity of arsenic oxide gene (aoxB) in endophytic bacteria of Pteris vittata in a Pb-Zn mining area in Wanshun

摘要:

【背景】近年来，由于金属矿的开采和冶炼、砷产品的加工与使用、煤的燃烧等各种因素，导致土壤环境中的砷污染越来越严重，导致许多人暴露于极度危险的砷毒毒害之下。【目的】研究四川的万顺铅锌矿区蜈蚣草根组织内生细菌aoxB基因的多样性，为提高土壤重金属污染生态修复效率提供理论依据。【方法】利用实时荧光定量PCR (Real-time quantitative PCR，qPCR)和限制性片段长度多态性(Restriction fragment length polymorphism，RFLP)技术，对四川省汉源县万顺铅锌矿区蜈蚣草根组织内生细菌aoxB基因表达量及多样性进行研究。【结果】qPCR结果表明，不同采样点间的蜈蚣草根组织内生细菌aoxB基因表达量存在明显差异，表现为选矿区>进山口>弃渣场>尾矿区>矿口。酶切图谱结果表明，不同采样点蜈蚣草根组织内生细菌aoxB基因多样性存在明显差异，多样性指数表现为尾矿>矿口>弃渣场>进山口>选矿区。Pearson相关分析显示，aoxB基因的表达量与重金属As之间呈显著负相关(p<0.05)，多样性指数则与重金属Pb和As之间呈极显著正相关(p<0.01)。系统发育分析显示，aoxB基因的优势菌群为α-变形菌门(Alphaproteobacteria)。【结论】蜈蚣草根组织中存在丰富的含aoxB基因内生细菌种群，这些内生细菌表现出潜在的应用价值。

Abstract:

[Background] In recent years, due to the mining and smelting of metal ores, the processing and use of arsenic products, the burning of coal and other factors, arsenic pollution in the soil environment has become more and more serious, causing many people to be exposed to extremely dangerous arsenic poisoning. [Objective] To study the diversity of endophytic bacteria aoxB gene in Pteris vittata root of Wanshun Pb-Zn mining area in Sichuan, and provide a theoretical basis for improving the efficiency of soil heavy metal pollution ecological restoration. [Methods] Real-time quantitative PCR (qPCR) and restriction fragment length polymorphism (RFLP) were used to study the abundance and diversity of arsenic oxidation gene (aoxB) of the endophytic bacteria in Pteris vittata root which were isolated from a Pb-Zn mining area in Hanyuan of Sichuan province, China. [Results] The results of QPCR showed that there was a significant difference in the expression of aoxB genes between the different sampling sites. The abundance aoxB gene were in the order of dressing area>entrance to the mountain>spoil area>mine tailings>mine mouth. The RFLP results showed that there were significant differences in the diversity index of the aoxB gene of endophytic bacteria among different sampling sites, and the diversity index of the species were in the order of mine tailings>mine mouth>spoil area>outside mine area>mine mouth. Pearson correlation analysis showed that the abundance of aoxB genes was negatively correlated with concentration of As (p<0.05), and the diversity index was positively correlated with concentration of Pb and As (p<0.01). Phylogenetic analysis showed that aoxB containing endophytic bacteria in the Pteris vittata were mainly belonged to Alphaproteobacteria. [Conclusion] The results showed that there were abundant endophytic bacterial populations containing aoxB gene in Pteris vittata root, and these endophytic bacteria showed potential application value.