Defense mechanisms of Acidithiobacillus caldus SM-1 responding to reactive oxygen species

Abstract:

[Objective] To discover the defense mechanisms of Acidithiobacillus caldus SM-1 responding to reactive oxygen species at the whole genome level. [Methods] The genomic DNA of At. caldus SM-1 was sequenced by the Roche 454 Genome Sequencer FLX instrument. Gene function was annotated by homology searching in the NCBI NR (non-redundant) and UniProt protein database. The KEGG database was used to reconstruct the metabolism pathways in the cell. Genes related to ROS defense mechanisms were identified through the comparative genomic analysis. [Results] Enzymatic and non-enzymatic antioxidant systems were both identified in the SM-1 genome. The former was used to eliminate the ROS and the latter was utilized to provide a reducing intracellular environment through maintaining the redox homeostasis in the cell. The robust DNA repair system was used to deal with DNA oxidative damage. In addition, whether the large number of transposable elements in the SM-1 genome might enhance the genome plasticity for adaptation to extreme bioleaching environments is still need further interpretation. [Conclusion] Genome sequence of SM-1 will help us to discover the ROS detoxification mechanisms of SM-1, and this will give us insights to construct the engineered stains with better bioleaching performance.