Arsenic speciation and bacterial diversity of Pteris vittata L. rhizosphere in arsenic-rich and natural mineral soils

Aims: Soil plays a crucial role in supporting diverse microbial life, and elevated arsenic levels can significantly disrupt these microorganisms' activities.This study aimed to investigate the heavy metal contents and arsenic speciation of the rhizosphere soils of Pteris vittata L. as well as the diversity, composition, and metagenomic functions of the bacterial community in the rhizosphere zone of arsenic-rich (ARS) and natural mineral soils (NMS). Methodology and results:The arsenic speciation analysis of the soil samples was carried out using the Highperformance Liquid Chromatography-inductively Coupled Plasma Mass Spectrometry (HPLC-ICPMS).The arsenic speciation analysis revealed that arsenic-rich soils and P. vittata samples from those soils had higher total arsenic content compared to natural mineral soils.Next-generation sequencing (NGS) was employed to evaluate the composition and functions of the soil bacterial communities.Amplicon sequencing, specifically targeting the V3-V4 region of the 16S rRNA gene, was carried out using the Illumina approach.Analysis of the filtered reads revealed that the phylum Actinobacteria, Proteobacteria, Chloroflexi, Gammatimonadetes, and Firmicutes were more abundant in arsenic-rich soils.While Acidobacteria, Verrumicrobia, Planctomycetes, Myxococcota, and Bacteroidetes were more abundant in natural mineral soils. Conclusion, significance and impact of study:The findings indicated that arsenic-rich soils harboured a more significant number of species but had lower overall diversity than natural mineral soils.Hence, arsenic-rich soil conditions influenced the composition of the bacterial communities in the soil.