Iron- and sulfur-oxidizing bacteria inhabiting rice rhizoplane play a significant role on arsenic biogeochemistry in flooded rice paddies, influencing arsenic translocation to rice grains. In the present study, the selective pressure of arsenic species on these microbial populations was evaluated. Rice roots from continuously flooded plants were incubated in iron sulfide (FeS) gradient tubes and exposed to either arsenate or arsenite. The biomass developed in the visible iron-oxidation band of the enrichments was analyzed by Scanning Electron Microscopy and Energy-Dispersive Spectroscopy (SEM-EDS) and the bacterial communities were characterized by 16S rRNA gene sequencing. Different Proteobacteria communities were selected depending on exposure to arsenate and arsenite. Arsenate addition favored the versatile iron-oxidizers Dechloromonas and Azospira, associated to putative iron (hydr)oxide crystals. Arsenite exposure decreased the diversity in the enrichments, with the development of the sulfur-oxidizer Thiobacillus thioparus, likely growing on sulfide released by FeS. Whereas sulfur-oxidizers were observed in all treatments, iron-oxidizers disappeared when exposed to arsenite. These results reveal a strong impact of different inorganic arsenics on rhizospheric iron-oxidizers as well as a crucial role of sulfur-oxidizing bacteria in establishing rice rhizosphere communities under arsenic pressure.
Exposure to Different Arsenic Species drives the Establishment of Iron- and Sulfur-oxidizing Bacteria on Rice Root Iron Plaques / S. Zecchin, M. Colombo, L. Cavalca. - In: WORLD JOURNAL OF MICROBIOLOGY & BIOTECHNOLOGY. - ISSN 0959-3993. - 35:8(2019 Aug).
|Titolo:||Exposure to Different Arsenic Species drives the Establishment of Iron- and Sulfur-oxidizing Bacteria on Rice Root Iron Plaques|
ZECCHIN, SARAH (Primo) (Corresponding)
COLOMBO, MILENA (Secondo)
CAVALCA, LUCIA (Ultimo) (Corresponding)
|Parole Chiave:||Iron-oxidizing bacteria; sulfur-oxidizing bacteria; arsenic; rice rhizosphere; rice iron plaques; gradient tubes|
|Settore Scientifico Disciplinare:||Settore AGR/16 - Microbiologia Agraria|
|Progetto:||Salubrità degli agroecosistemi: processi chimici, biochimici e biologici che regolano la mobilità dell'As nei comparti suolo-acqua-pianta|
|Data di pubblicazione:||ago-2019|
|Data ahead of print / Data di stampa:||lug-2019|
|Digital Object Identifier (DOI):||http://dx.doi.org/10.1007/s11274-019-2690-1|
|Appare nelle tipologie:||01 - Articolo su periodico|
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