Effects of different concentrations of chlormequat chloride on bacterial community composition and diversity in...

The application of pesticides may have significant impacts on soil environment and communities. In order to understand the deep relationship between the application of chlormequat chloride (CC) and the bacterial community in peanut soil, high-resolution characterization was performed using peanut soil samples (12 points; 0-20 cm rhizosphere soil) from untreated and sprayed with different concentrations of CC. Experimental data showed that with the increase of concentration, operational taxonomic units (OTUs) richness showed a decreasing tendency. The OTUs richness at low concentration (D, 50% CC diluted 5000 times, 45 g ai/ha), medium concentration (M, 50% CC diluted 300 times, 75 g ai/ha), and high concentration (G, 50% CC diluted 1000 times, 225 g ai/ha) were 5583, 5430, and 3910, respectively. Low concentrations increased the composition and relative abundance of soil bacterial communities. In contrast, high concentrations significantly reduced bacterial diversity. As the concentration of CC increases, the abundance of Proteobacteria decreases, while the abundance of Firmicutes and Bacteroidetes increases. The number of Acidobacterium and Bacteroidetes increased in groups D and M, while it decreased in group G. D, M and G groups showed a decrease in the abundance of Pseudomonas, polaromonas, and Azovibrio compared to CK, while the abundance of Flavobacterium increased. In addition, the abundance of Rahnella1 decreased in groups D and M, while the abundance increased in group G. The main metabolic pathways included the metabolisms of nucleotides, terpenoids, polyketides, other amino acids, cofactors, vitamins, lipids, glycan biosynthesis, energy, carbohydrates, xenobiotics, amino acids, and other secondary metabolites.