TY - JOUR
T1 - Iron minerals inhibit the growth of Pseudomonas brassicacearum J12 via a free-radical mechanism
T2 - Implications for soil carbon storage
AU - Du, Hai Yan
AU - Yu, Guang Hui
AU - Sun, Fu Sheng
AU - Usman, Muhammad
AU - Goodman, Bernard A.
AU - Ran, Wei
AU - Shen, Qi Rong
N1 - Publisher Copyright:
© Author(s) 2019.
PY - 2019/4/8
Y1 - 2019/4/8
N2 - Natural minerals in soil can inhibit the growth of bacteria that protect organic carbon from decay. However, the mechanism inhibiting the bacterial growth remains poorly understood. Here, using a series of cultivation experiments and biological, chemical and synchrotron-based spectral analyses, we showed that kaolinite, hematite, goethite and ferrihydrite had a significant inhibitory effect on the growth of the model bacteria Pseudomonas brassicacearum J12, which was more prominent with a concentration of 25 mgmL-1 than it was with either 10 or 5 mgmL-1. In contrast, montmorillonite promoted the growth of J12. Compared to Al-containing minerals, Fe(III)-containing minerals produced more hydroxyl radical (HO q ) that has high efficiency for the inhibition of J12. Moreover, a significant positive correlation between HO q radical and Fe(II) was found, suggesting that Fe(II) contributes to the generation of HO q . Furthermore, both micro X-ray fluorescence and X-ray photoelectron spectroscopies indicated that surface Fe(III) was reduced to Fe(II), which can produce HO q through the wellknown Fenton reaction series. Together, these findings indicate that the reduced surface Fe(II) derived from Fe(III)- containing minerals inhibits the growth of Pseudomonas brassicacearum J12 via a free-radical mechanism, which may serve as a ubiquitous mechanism between iron minerals and all of the heterotrophic bacteria in view of taxonomically and ecologically diverse heterotrophic bacteria from terrestrial environments as a vast source of superoxide.
AB - Natural minerals in soil can inhibit the growth of bacteria that protect organic carbon from decay. However, the mechanism inhibiting the bacterial growth remains poorly understood. Here, using a series of cultivation experiments and biological, chemical and synchrotron-based spectral analyses, we showed that kaolinite, hematite, goethite and ferrihydrite had a significant inhibitory effect on the growth of the model bacteria Pseudomonas brassicacearum J12, which was more prominent with a concentration of 25 mgmL-1 than it was with either 10 or 5 mgmL-1. In contrast, montmorillonite promoted the growth of J12. Compared to Al-containing minerals, Fe(III)-containing minerals produced more hydroxyl radical (HO q ) that has high efficiency for the inhibition of J12. Moreover, a significant positive correlation between HO q radical and Fe(II) was found, suggesting that Fe(II) contributes to the generation of HO q . Furthermore, both micro X-ray fluorescence and X-ray photoelectron spectroscopies indicated that surface Fe(III) was reduced to Fe(II), which can produce HO q through the wellknown Fenton reaction series. Together, these findings indicate that the reduced surface Fe(II) derived from Fe(III)- containing minerals inhibits the growth of Pseudomonas brassicacearum J12 via a free-radical mechanism, which may serve as a ubiquitous mechanism between iron minerals and all of the heterotrophic bacteria in view of taxonomically and ecologically diverse heterotrophic bacteria from terrestrial environments as a vast source of superoxide.
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U2 - 10.5194/bg-16-1433-2019
DO - 10.5194/bg-16-1433-2019
M3 - Article
AN - SCOPUS:85064110515
SN - 1726-4170
VL - 16
SP - 1433
EP - 1445
JO - Biogeosciences
JF - Biogeosciences
IS - 7
ER -