Quorum-sensing system in Acidithiobacillus ferrooxidans involved in its resistance to Cu²⁺

Abstract

Aims: The purpose of this study was to search for the relationship between quorum sensing (QS) and Cu²⁺ resistance in Acidithiobacillus ferrooxidans.

Methods and results: Resistance to Cu²⁺ of A. ferrooxidans significantly decreased with the treatment dose of a synthetic QS blocker (5Z)-4-bromo-5-(bromomethylene)-2(5H)-furanone (FUR). Relative differences in expression of the QS genes afeI, afeR and Cu²⁺ resistance-associated genes afe0329, afe0454 were examined in the presence of Cu²⁺ and/or FUR compound. The expression of QS genes afeI and afeR increased significantly with 50 mmol l⁻¹ Cu²⁺ in the culture, while for samples treated with both 50 mmol l⁻¹ Cu²⁺ and 0.01 μg ml⁻¹ FUR compound, they showed little changes compared with control, and the expression of afe0329 and afe0454 genes increased slightly either. These results showed that QS system was positively related to the mechanism of Cu²⁺ resistance.

Conclusions: QS system in A. ferrooxidans involved in its resistance to Cu²⁺.

Significance and impact of the study: The mechanisms of Cu²⁺ resistance in A. ferrooxidans could be revealed on a population level rather than on a single-cell level. Our work also provides useful data for further selection of A. ferrooxidans strains with suitable Cu²⁺ resistance that could probably increase the bioleaching efficiency.