Bacterial Community Analysis Using DGGE of 16S rDNA in Organic, Intensive and Conventional Agroecosystems.

Bacterial diversity is one of the most important factors to quantify a sustainable and healthy ecosystem. The greater the diversity, the more resilient is the system to any change or disturbance. Continuous exposure to disturbance, presence of a pollutant, or crop management factors such as mono-cropping or use of fertilizers can all reduce bacterial diversity. Only a few species will be well suited to that particular environment and increase in abundance. Identifying and quantifying bacterial diversity has been difficult until recently as new molecular tools have become available. Today we can measure bacterial community diversity by techniques such as DGGE and RFLP. In this study, we compared bacterial diversity in soils under different management conditions. Three replicate soil samples (0-7.5 cm depth) were collected from an organic agricultural field and from fields with conventional and reduced agricultural inputs. Bacterial DNA was extracted and the 16s rRNA gene was amplified using polymerase chain reaction (PCR). Two universal bacterial primers PRBA338F and PRUN518R were used in the PCR reaction. Community profiles obtained using denaturation gradient gel electrophoresis (DGGE) indicated that bacterial diversity is influenced greatly by management practices.