Abstract:
Using high throughput sequencing and real-time PCR techniques, the effects of added Zn on relative abundance of aminoglycoside antibiotic resistance genes (ARGs), mobile genetic elements (MGEs) and bacterial communities in soil were studied by indoor culture. The results show that Zn concentration and treatment time had different effects on aminoglycoside ARGs and MGEs.After treatment with 1 000 mg·kg
-1 Zn for 60 d, the relative abundances of
acc, aacC1 and integron
int11 were the highest, which were 4.1, 9.7 and 3.7 times as those of the control, respectively. When 800 mg·kg
-1 Zn was treated for 60 d, the relative abundance of
aac(6')-Ⅱ was the highest, which was 13.7 times as that of the control. The relative abundance of transposon
Tp614 was significantly increased only after 60 d of Zn treatment, and the highest relative abundance was obtained at 100 mg·kg
-1 Zn treatment, which was 4.6 times that of the control. Zn stress decreased the diversity index of bacterial community and increased the dominance index, indicating that Zn toxicity caused the disappearance of sensitive bacteria and the increase of resistant bacteria. Redundancy analysis show that the effect of Zn stress duration on bacterial community structure was greater than that of Zn concentration. When the treatment time was equal, the structure of soil bacterial community was significantly different between low concentration Zn (100-400 mg·kg
-1) and high concentration Zn (800-1 000 mg·kg
-1). Zn treatment was negatively correlated with
Nocardioides, Adhaeribacter and
Arthrobacter, and positively correlated with
Flavisolibacter, Sphingomonas and
Solirubrobacter. The network coexistence analysis show that
acc,
aac(6')-Ⅱ,
aacC1 and
int11,
IS613 had high connections under Zn stress;
Steroidobacter was connected to
Tp614, which may be the potential host of
Tp614. The studies have shown that high concentration of Zn pollution can accelerate the spreading and diffusion of soil ARGs. Even if low concentration of Zn exists for a long time, some ARGs and MGEs can be induced, and the risk of horizontal transfer can also be increased, which is worthy of attention.