title: Bacterial ability in AsIII oxidation and AsV reduction: Relation to arsenic tolerance, P uptake, and siderophore production.
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.
authors.affiliation: State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Jiangsu 210046, China; Soil and Water Science Department, University of Florida, Gainesville, FL 32611, United States.
authors.forename: Piyasa
authors.initials: P
authors.lastname: Ghosh
authors.affiliation: Horticultural Sciences Department, University of Florida, Gainesville, FL 32611, United States.
authors.forename: Bala
authors.initials: B
authors.lastname: Rathinasabapathi
authors.affiliation: Soil and Water Science Department, University of Florida, Gainesville, FL 32611, United States.
authors.forename: Max
authors.initials: M
authors.lastname: Teplitski
authors.affiliation: State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Jiangsu 210046, China; Soil and Water Science Department, University of Florida, Gainesville, FL 32611, United States. Electronic address: lqma@ufl.edu.
authors.forename: Lena Q
authors.initials: LQ
authors.lastname: Ma
mesh_terms: D001149:Arsenates / Q000032:analysis / Q000737:chemistry*; D018053:Arsenites / Q000032:analysis / Q000737:chemistry*; D024881:Drug Resistance, Bacterial; D004361:Drug Tolerance; D010084:Oxidation-Reduction; D010710:Phosphates / Q000378:metabolism*; D011549:Pseudomonas / Q000378:metabolism*; D032495:Pteris / Q000382:microbiology; D058441:Rhizosphere; D017262:Siderophores / Q000032:analysis* / Q000096:biosynthesis
chemical_list: D001149:Arsenates; D018053:Arsenites; D010710:Phosphates; D017262:Siderophores; C015001:arsenite; C025657:arsenic acid
keywords: Arsenic tolerance; Arsenic-resistant bacteria; AsIII oxidation; AsV reduction; Siderophore