Alcaligenes faecalis associated with Mimosa calodendron rizhosphere assist plant survival in arsenic rich soils.
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Date
2017
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Abstract
The ferruginous rupestrian grasslands (FRG) in the Iron Quadrangle (IQ) are ecosystems characterized by rocky
soils with reduced availability of water and nutrients, but high levels of metals. In order to comprehend the interference of microorganisms on the adaptive process of endemic plant Mimosa calodendrum (Fabaceae), bacteria
associated with its roots and rhizosphere were isolated. Fourteen isolates were obtained and subsequently grown
in the presence of different concentrations of arsenic (As) species. The isolate Mc250, an Alcaligenes faecalis
strain, resisted to 10 mM of As (III) and 800 mM of As (V). In the presence of this strain, atomic spectrometer
detected a reduction of 55% for As (III) and 72% for As (V) respectively in 10 mM and 500 mM solution.
Scanning electron microscopy of this isolate demonstrated morphological modification and EDX spectroscopy
revealed the presence of both As species adsorbed on the membrane, justifying the removal observed in the in
vitro assays. To validate this potential removal of As in vivo, tomato plants were used as grown model in the
presence and absence of A. faecalis in soil previously contaminated with 5 mM of As (III). After 14 days, plants
from contaminated soil had their growth improved when compared to untreated control plants. All these results
suggest for the first time that plant-associated bacteria from FRG-IQ present potential for soil rhizoremediation
and may benefit the adaptive processes of plants in extreme environments including application in recovering
degraded areas.
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Keywords
Arsenic removal, Iron Quadrangle, Arsenic resistant bacteria, Plant growthpromoting rhizobacteria, Rhizoremediation
Citation
FELESTRINO, E. B. et al. Alcaligenes faecalis associated with Mimosa calodendron rizhosphere assist plant survival in arsenic rich soils. Journal of soil science and plant nutrition, v. 17, n. 4, p. 1102-1115, 2017. Disponível em: <https://scielo.conicyt.cl/scielo.php?script=sci_abstract&pid=S0718-95162017000400019&lng=es&nrm=i>. Acesso em: 22 fev. 2019.