| Bioremediation technology is an important way to rehabilitate soils polluted by petroleum and soil function restoration.In this process,soil community microorganisms has played a key role.Therefore,it is particularly important to further improve the bioremediation effect to explore the changes in the community of high-efficiency biodegradable bacteria in petroleum polluted soil and to evaluate the differences in the metabolism of key functional genes of petroleum refractory components under different remediation conditions at the gene level.In this study,the Weihe terrace silty loam and loess tableland silty loam were selected as the test and the Agropyron cristatum?L.?Gaertn.and Cynodon dactylon?L.?Pers.were used as the repairing plants.The phyto-microbial combined remediation test was conducted on the petroleum contaminated soil under the conditions of 0 mg·kg-1,3,000 mg·kg-1,7,000mg·kg-1 and 10,000 mg·kg-1,respectively.The main contents were listed as follows:?1?To sequence DNA of 24 groups of soil samples under different experimental conditions by high-throughput technology.To study the change characteristics of soil bacterial community structure under different experimental conditions through analysis of OTU,dilution curve,aroma index,heat map,PCA and RDA;?2?To detect and clone the key functional genes of persistent petroleum component of Catechol 2,3-dioxygenases?C23O?,Aromatic dioxygenase?QHM?and Phenol hydroxylase?Ahd?.To expound the mechanism of petroleum degradation from molecular level;?3?To quantify the functional gene expression in 12 groups of Weihe terrace silty loam soil samples under different experimental conditions on the basis of constructing a standard curve through real-time fluorescence quantitative polymerase chain reaction?qPCR?.The main results are as follows:?1?Under different phytoremediation experimental conditions,the main bacterial communities at the phylum level in the petroleum contaminated phytoremediation soil were as follows:Proteobacteria,Acidobacteria,Crenarchaeota,Actinobacteria,Bacteroidetes,Planctomycetes,Chloroflexi,WS3,Gemmatimonadetes,Firmicutes,Nitrospirae,Euryarchaeota,Verrucomicrobia,Armatimonadetes,Elusimicrobia.?2?The soil bacterial community structure and diversity were affected by petroleum pollution concentration in the soils,phytoremediation and different soils,especially petroleum pollution concentration and phytoremediation.With the increase of petroleum concentration,the dominant bacterial community in soil increased in step with the concentration of pollution.Generally speaking,the higher concentration of petroleum contaminated soil was conducive to the growth of most bacteria in the soil;The different phytoremediation plants had markedly different physical and chemical properties of soil.?3?The key functional genes of persistent petroleum component of C23O,QHM and Ahd were detected that were consistent with the size of the target gene,470bp,85bp,310bp,respectively.The results showed that the remediation soil contained the key functional genes of the above persistent petroleum component.?4?The real-time fluorescence quantitative PCR reaction was performed with SYBR configuration reaction system to construct standard curve for C23O,QHM and Ahd gene?E?:y=-3.77x+38.2?E=84.30%?;y=-3.78x+39.72?E=83.9%?;y=-2.97x+37.13?E=117%?,respectively.?5?According to the absolute fluorescence quantitative analysis of functional genes repaired in 12 groups of different experimental conditions,Cynodon dactylon?L.?Pers.could promote copies of C23O and Ahd functional gene in petroleum-contaminated soil.However,phytoremediation by Cynodon dactylon?L.?Pers.may inhibit the copy of QHM functional gene.Furthermore,the high concentration petroleum contaminated soil?7000 mg/kg-10000mg/kg?can promote the copy of Ahd functional gene. |
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