The abundance and mineral-weathering effectiveness of Bacillus strains in the altered rocks and the soil.

In this study, we collected different levels of altered rocks of a rocky mountain and the adjacent soil and characterized the abundance and weathering effectiveness of Bacillus strains. Based on qPCR and culture-dependent approaches, the gene copies or the numbers of Bacillus strains were significantly higher in the soil than in the altered rocks, while the ratio of the gene copies or the numbers of Bacillus strains to those of total bacteria was higher in the less altered rock, followed by the more altered rock and the soil. The relative abundance of the highly active Al-solubilizing Bacillus strains was higher in the more altered rock, followed by the less altered rock and the soil. Among the Al-solubilizing Bacillus species, 30-36% of them were different between the altered rocks and the soil, however, similar Al-solubilizing Bacillus species were found in the less altered rocks and the more altered ones. The results showed the alteration-related changes in the abundance and mineral weathering effectiveness of Bacillus strains and suggested the ecological adaptation of the mineral-weathering Bacillus populations and their role in mineral weathering in the rock and soil environments.