Comparison of bacterial diversity in soils of rice-monocropping and vegetable rotation by PCR-RFLP analysis of 16S rRNA gene

PCR-RFLP analysis, a culture-independent method was used to compare the bacterial community structure in two contrasting types of soils: soil monocropped with rice and soil rotated with different kinds of vegetables. Bacterial 16S rRNA gene (16S rDNA) libraries of the two types of soils were built and the 16S rDNA were then reamplified and digested with restriction endonuclease (Hinf I). In the vegetable soil, there were total 33 16S rDNA genotypes in 75 recombinants, while in rice soil there were total 17 16S rDNA genotypes in 55 recombinants. Compared to the rice paddy soil, the vegetable soil showed higher bacterial diversity index and most of the clones belonged to Proteobacteria γ, α and ß subdivisions, while a few clones were affiliated with high G+C bacteria, Chloroflexus and Nitrospina bacteria. In rice soil, half of the clones belonged to Proteobacteria γ and ß subdivisions, with the remaining half belonging to high G+C bacteria, Prosthecobacter and Sphingobacterium.