The Impact of Acetochl or The Bacterial Diversity in Soil

The impact of the herbicide acetochlor on the culturable heterotrophic and phylogenetic diversity of the bacterial community in soil was investigated. The changes in diversity were monitored for soils treated with 1 0mg, 5 0mg and 10 0mg acetochlor g 1 soil for 40 day period respectively. The culturable heterotrophic bacterial diversity was investigated by colony morphology on solid LB medium. Phylogenetic diversity was measured by 16S rDNA fragments banding on denaturing gradient gel electrophoresis (DGGE) gels, which were amplified from the total DNA extracted from soil. The Shannon Wiener index of diversity (H) , richness (S) and evenness (E H) were used to measure the changes in the bacterial community in soils. The results showed both the culturable heterotrophic diversity and phylogenetic diversity decreased as the treatment with acetochlor, and the different rates of treatment with acetochlor had different impact on the diversity. Bands appearing to be either enhanced or inhibited as a result of the acetochlor treatment were excised and sequenced. Sequencing of excised DGGE bands indicated an obvious impact on two subdivisions of the Proteobacteria (α Proteobacteria and γ Proteobacteria). This revealed microbial community changes can occur due to the application of acetochlor in soil.