State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Jiangsu, 210023, China.
Horticultural Sciences Department, University of Florida, Gainesville, FL, 32611, United States.
J Hazard Mater. 2017 Jan 5;321:146-153. doi: 10.1016/j.jhazmat.2016.08.079. Epub 2016 Sep 1.
Microbially-mediated arsenic (As) transformation in soils affects As speciation and plant uptake. However, little is known about the impacts of As on bacterial communities and their functional genes in the rhizosphere of As-hyperaccumulator Pteris vittata. In this study, arsenite (AsIII) oxidase genes (aroA-like) and arsenate (AsV) reductase genes (arsC) were amplified from three soils, which were amended with 50mgkg As and/or 1.5% phosphate rock (PR) and grew P. vittata for 90 d. The aroA-like genes in the rhizosphere were 50 times more abundant than arsC genes, consistent with the dominance of AsV in soils. According to functional gene alignment, most bacteria belonged to α-, β- and γ-Proteobacteria. Moreover, aroA-like genes showed a higher biodiversity than arsC genes based on clone library analysis and could be grouped into nine clusters based on terminal restriction fragment length polymorphism (T-RFLP) analysis. Besides, AsV amendment elevated aroA-like gene diversity, but decreased arsC gene diversity. Redundancy analysis indicated that soil pH, available Ca and P, and AsV concentration were key factors driving diverse compositions in aroA-like gene community. This work identified new opportunities to screen for As-oxidizing and/or -reducing bacteria to aid phytoremediation of As-contaminated soils.
土壤中微生物介导的砷（As）转化会影响 As 的形态和植物的吸收。然而，对于砷在蜈蚣草（As 超富集植物）根际的细菌群落及其功能基因的影响，我们知之甚少。在这项研究中，我们从三种土壤中扩增了亚砷酸盐（AsIII）氧化酶基因（aroA 样）和砷酸盐（AsV）还原酶基因（arsC），这些土壤分别添加了 50mgkg 的 As 和/或 1.5%的磷矿（PR），并种植了 90 天的蜈蚣草。根际的 aroA 样基因比 arsC 基因丰富 50 倍，与土壤中 AsV 的优势一致。根据功能基因比对，大多数细菌属于 α-、β-和 γ-变形菌门。此外，基于克隆文库分析，aroA 样基因的生物多样性高于 arsC 基因，并且可以根据末端限制性片段长度多态性（T-RFLP）分析分为九个聚类。此外，AsV 的添加提高了 aroA 样基因的多样性，但降低了 arsC 基因的多样性。冗余分析表明，土壤 pH、有效 Ca 和 P 以及 AsV 浓度是驱动 aroA 样基因群落组成多样化的关键因素。这项工作为筛选砷氧化和/或还原细菌以帮助修复砷污染土壤提供了新的机会。
