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

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.