PCR-DGGE Analysis Of The Bacterial Communities In Paddy Fields In Fujian Province And Cloning Of Oil-degerading Genes

Bacterial community in paddy soil contributes greatly to soil fertility and available nutriments for rice growth. Based on constitution of the bacterial community, scientists can predict dynamic change of the organic matter in the soil. Therefore it could be used as an index of development of the fertility in paddy field. 16S rDNA-PCR-DGGE, a cultivation-independent approach, was used to analyze the bacterial communities in paddy soils in Fujian Province. The samples from bulk soil and rhizosphric soil located at six different ecological regions were collected. Total DNA of the samples were directly extracted and amplified with primers F341GC and R534 targeting the 16S rDNA V3. The amplified fragments were analyzed by denaturing gradient gel electrophoresis (DGGE). Cluster analysis revealed that there was a high diversity of bacterial community compositions among different soil samples tested. Basically they could be grouped to four cladodes: Mindong(East), Minnan(South), Minbei (North) and Minxi(West) ecological regions. 16S rDNA-PCR-DGGE profiles from bulk and rhizospheric soils in the same region showed less bacterial diversity but more similarity. The bacterial communities from bulk and rhizospheric soils in Longyan shared mostly similar DGGE banding patterns, and the banding patterns in Yongtai exhibited the highest diversity. Eleven DGGE bands recovered were re-amplified, sequenced and aligned with Blast. The results indicated that ten of the targeting fragments belong to uncultivated bacteria, implying DGGE technique having priority in analyzing uncultivated bacteria.Petroleum brings great economic benefits to human being. However, it has caused serious threat to environment and human health. The approches, including physical, chemical and biological, for removing these pollutants from the environment have so far been developed by researchers in the World. The bioremediation with microorganisms has been considered as the most efficient technique for this purpose, due to its high efficiency, low cost and free of second pollution. In this study, 3 oil-degrading bacterial strains, which could used raw iol as sole carbon source and partly decomposed petroleum, were screened via gene mining procedures. The genes alkB and C23O responsible for oil degredation were cloned and amplied.