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LeTourneau MK, Marshall MJ, Grant M, Freeze PM, Strawn DG, Lai B, Dohnalkova AC, Harsh JB, Weller DM, Thomashow LS. Phenazine-1-Carboxylic Acid-Producing Bacteria Enhance the Reactivity of Iron Minerals in Dryland and Irrigated Wheat Rhizospheres. Environ Sci Technol 2019; 53:14273-14284. [PMID: 31751506 DOI: 10.1021/acs.est.9b03962] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Phenazine-1-carboxylic acid (PCA) is a broad-spectrum antibiotic produced by rhizobacteria in the dryland wheat fields of the Columbia Plateau. PCA and other phenazines reductively dissolve Fe and Mn oxyhydroxides in bacterial culture systems, but the impact of PCA upon Fe and Mn cycling in the rhizosphere is unknown. Here, concentrations of dithionite-extractable and poorly crystalline Fe were approximately 10% and 30-40% higher, respectively, in dryland and irrigated rhizospheres inoculated with the PCA-producing (PCA+) strain Pseudomonas synxantha 2-79 than in rhizospheres inoculated with a PCA-deficient mutant. However, rhizosphere concentrations of Fe(II) and Mn did not differ significantly, indicating that PCA-mediated redox transformations of Fe and Mn were transient or were masked by competing processes. Total Fe and Mn uptake into wheat biomass also did not differ significantly, but the PCA+ strain significantly altered Fe translocation into shoots. X-ray absorption near edge spectroscopy revealed an abundance of Fe-bearing oxyhydroxides and phyllosilicates in all rhizospheres. These results indicate that the PCA+ strain enhanced the reactivity and mobility of Fe derived from soil minerals without producing parallel changes in plant Fe uptake. This is the first report that directly links significant alterations of Fe-bearing minerals in the rhizosphere to a single bacterial trait.
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Affiliation(s)
- Melissa K LeTourneau
- Department of Crop & Soil Sciences , Washington State University , Pullman , Washington 99164-6420 , United States
- United State Department of Agriculture - Agricultural Research Service , Wheat Health, Genetics and Quality Research Unit , Pullman , Washington 99164-6430 , United States
| | - Matthew J Marshall
- Earth & Biological Sciences Directorate , Pacific Northwest National Laboratory , Richland , Washington 99352 , United States
| | - Michael Grant
- Department of Crop & Soil Sciences , Washington State University , Pullman , Washington 99164-6420 , United States
| | - Patrick M Freeze
- Department of Crop & Soil Sciences , Washington State University , Pullman , Washington 99164-6420 , United States
| | - Daniel G Strawn
- Department of Soil and Water Systems , University of Idaho , Moscow , Idaho 83844-2340 , United States
| | - Barry Lai
- Advanced Photon Source , Argonne National Laboratory , Argonne , Illinois 60439 , United States
| | - Alice C Dohnalkova
- Environmental Molecular Sciences Laboratory , Pacific Northwest National Laboratory , Richland , Washington 99352 , United States
| | - James B Harsh
- Department of Crop & Soil Sciences , Washington State University , Pullman , Washington 99164-6420 , United States
| | - David M Weller
- United State Department of Agriculture - Agricultural Research Service , Wheat Health, Genetics and Quality Research Unit , Pullman , Washington 99164-6430 , United States
| | - Linda S Thomashow
- United State Department of Agriculture - Agricultural Research Service , Wheat Health, Genetics and Quality Research Unit , Pullman , Washington 99164-6430 , United States
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Mullane JM, Flury M, Iqbal H, Freeze PM, Hinman C, Cogger CG, Shi Z. Intermittent rainstorms cause pulses of nitrogen, phosphorus, and copper in leachate from compost in bioretention systems. Sci Total Environ 2015; 537:294-303. [PMID: 26282763 DOI: 10.1016/j.scitotenv.2015.07.157] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2015] [Revised: 07/30/2015] [Accepted: 07/31/2015] [Indexed: 05/15/2023]
Abstract
Bioretention systems rely on vegetation and mixtures of soil, sand, and compost to filter stormwater runoff. However, bioretention systems can also leach metals and nutrients, and compost may be a major contributor to this leaching. To safely implement bioretention systems, it is crucial to determine the composition of compost leachate. We characterized and quantified the leachate composition of compost following intermittent, simulated storm events. Columns of municipal compost were irrigated to simulate 6-month, 24-hour rain storms in the Seattle-Tacoma region. Outflow was analyzed for pH, electrical conductivity (EC), particulate concentration, surface tension, dissolved organic carbon (DOC), nitrogen, phosphorus, and copper. Results indicate a decrease of chemical concentrations over the course of individual storms and following repeated storms, but each new storm released another peak of constituents. The decrease in phosphorus, copper, and DOC concentrations with repeated storms was slower than for nitrate and EC. Nuclear magnetic resonance (NMR) and Fourier transform infrared spectroscopy (FTIR) showed that the DOC consisted mainly of aliphatic and aromatic components typical of fulvic and humic acids. Less than 3% of the original copper content from the compost leached out even after nine storm events. Nonetheless, copper concentrations in the leachate exceeded regulatory discharge standards. Our results show that compost can serve as a sustained source of leaching of nutrients and metals.
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Affiliation(s)
- Jessica M Mullane
- Department of Crop and Soil Sciences, Washington State University, Puyallup, WA 98371, Pullman, WA 99164, USA
| | - Markus Flury
- Department of Crop and Soil Sciences, Washington State University, Puyallup, WA 98371, Pullman, WA 99164, USA.
| | - Hamid Iqbal
- Department of Crop and Soil Sciences, Washington State University, Puyallup, WA 98371, Pullman, WA 99164, USA; Institute of Environmental Sciences and Engineering, School of Civil and Environmental Engineering, National University of Sciences and Technology, Sector H-12, Islamabad, Pakistan
| | - Patrick M Freeze
- Department of Crop and Soil Sciences, Washington State University, Puyallup, WA 98371, Pullman, WA 99164, USA
| | - Curtis Hinman
- Natural Resources Program Extension, Washington State University, Puyallup, WA 98371, USA
| | - Craig G Cogger
- Department of Crop and Soil Sciences, Washington State University, Puyallup, WA 98371, Pullman, WA 99164, USA
| | - Zhenqing Shi
- Department of Crop and Soil Sciences, Washington State University, Puyallup, WA 98371, Pullman, WA 99164, USA
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