Bacterial ability in AsIII oxidation and AsV reduction: Relation to arsenic tolerance, P uptake, and siderophore production. (November 2015)

• Record Type: Journal Article
• Authors: Ghosh, Piyasa; Rathinasabapathi, Bala; Teplitski, Max; Ma, Lena Q.
• Is Part Of: Chemosphere. Volume 138(2015)
• Page Start: 995
• Page End: 1000
• Publication Date: 2015-11
• Subjects: Arsenic tolerance -- AsIII oxidation -- AsV reduction -- Siderophore -- Arsenic-resistant bacteria; Pollution -- Periodicals; Pollution -- Physiological effect -- Periodicals; Environmental sciences -- Periodicals; Atmospheric chemistry -- Periodicals; 551.511
• DOI: 10.1016/j.chemosphere.2014.12.046
• Languages: English
• ISSNs: 0045-6535

Abstract

Graphical abstract: Highlights: Bacteria efficient in arsenite (AsIII) oxidation were more resistant to AsIII. Bacteria efficient in arsenate (AsV) reduction were more resistant to AsV. Bacteria efficient in siderophore production were more efficient in AsIII oxidation. AsV induced bacterial uptake of P probably via up-regulate P transporters. Both AsIII oxidation and AsV reduction are important for bacterial arsenic resistance. Abstract: The relationship between bacterial ability in arsenic transformation, siderophore production, and P uptake was investigated using six arsenic-resistant bacteria isolated from the rhizosphere of arsenic-hyperaccumulator Pteris vittata . Bacterial strains of PG5 and 12 were better arsenite (AsIII) oxidizers (31–46 vs. 6.2–21% of 1 mM AsIII) whereas PG 6, 9, 10 and 16 were better arsenate (AsV) reducers (58–95 vs. 7.5–46% of 1 mM AsV). Increase in AsV concentration from 0 to 1 mM induced 3.0–8.4 times more P uptake by bacteria but increase in P concentration from 0.1 to 1 mM reduced AsV uptake by 17–71%, indicating that P and AsV were taken up by P transporters. Bacteria producing more siderophores (PG5 and 12; >73 μM equiv) showed greater AsIII oxidation and AsIII resistance than those producing less siderophore (PG 6, 9, 10 and 16; <23 μM equiv). This observation was further supported by results obtained from mutants of Pseudomonas fluorescens impaired in siderophore production, as they were 23–25% less tolerant to AsIII than the wild-type. Arsenic-resistant bacteria increased their arsenic tolerance by retaining less arsenic in cells via efficient AsIII oxidation and AsV reduction, which were impacted by P uptake and siderophore production.