【摘要】：農(nóng)田土壤中抗生素及抗性基因的復(fù)合污染已給生態(tài)環(huán)境安全和人體健康帶來(lái)了全新隱患。針對(duì)厭氧條件下,反硝化作用過(guò)程對(duì)土壤抗生素乃至抗性基因消減影響的研究一直相對(duì)較少。因而,本研究采集牛糞堆積池塘周邊底層農(nóng)田土壤作為目標(biāo)污染土壤,重點(diǎn)研究反硝化作用過(guò)程對(duì)土壤磺胺嘧啶及抗性基因消減動(dòng)態(tài)的影響。結(jié)果表明:相較于原始污染土壤處理(T1),添加了NO_3~ -N的處理(T2)可以顯著強(qiáng)化土壤和水相中反硝化速率,提升N_2O的產(chǎn)氣速率,促進(jìn)土壤中磺胺嘧啶濃度和抗性基因豐度的快速降低;同時(shí)發(fā)現(xiàn)土壤反硝化基因(nir K、nir S和nos Z)與磺胺類抗性基因(sul Ⅰ和sul Ⅱ)呈顯著負(fù)相關(guān)(P0.05),說(shuō)明當(dāng)NO_3~ -N底物越充足,土壤反硝化細(xì)菌活性往往被激活,其反硝化功能基因表達(dá)就越活躍,土壤反硝化作用過(guò)程就越強(qiáng)烈,從而反饋?zhàn)饔么龠M(jìn)磺胺嘧啶抗生素的厭氧消減,進(jìn)而有助于sul系列抗性基因豐度的顯著衰減;同時(shí)通過(guò)高通量測(cè)序技術(shù)及對(duì)反硝化細(xì)菌的分離篩選后,發(fā)現(xiàn)變形菌門(Proteobacteria)賴氨酸芽胞桿菌屬(Lysinibacillus)的細(xì)菌是土壤厭氧反應(yīng)前后的主導(dǎo)優(yōu)勢(shì)菌群,對(duì)于強(qiáng)化反硝化過(guò)程和促進(jìn)磺胺嘧啶及sul抗性基因的消減發(fā)揮了潛在的積極作用。本研究結(jié)果可為探明土壤中抗生素的厭氧消減過(guò)程和緩解抗性基因的擴(kuò)散傳播提供新穎的認(rèn)知基礎(chǔ)。
[Abstract]:The compound contamination of antibiotics and resistant genes in farmland soil has brought new hidden danger to ecological environment safety and human health. The effect of denitrification on soil antibiotic and resistance gene subtractive has been relatively little under anaerobic condition. Therefore, the bottom farmland soil around the cow dung accumulation pond was collected as the target polluted soil, and the effects of denitrification on the dynamics of sulfadiazine and resistance gene subtractive were studied. The results showed that compared with the original polluted soil treatment (T1), the denitrification rate in soil and water phase was significantly enhanced by adding NO_3~ + -N (T2), and the gas production rate of N2O was increased. Promoting the rapid decrease of sulfadiazine concentration and resistance gene abundance in soil; It was also found that soil denitrification genes (nir Knir S and nos Z) were negatively correlated with sulfonamide-resistant genes (sul 鈪，

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