The substrate-dependent regulatory effects of the AfeI/R system in Acidithiobacillus ferrooxidans reveals the novel regulation strategy of quorum sensing in acidophiles |
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Authors: | Xue-Yan Gao Chang-Ai Fu Likai Hao Xiu-Feng Gu Rui Wang Jian-Qiang Lin Xiang-Mei Liu Xin Pang Cheng-Jia Zhang Jian-Qun Lin Lin-Xu Chen |
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Institution: | 1. State Key Laboratory of Microbial Technology, Shandong University, No. 72 Binhai Road, Qingdao, 266237 China;2. State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, No. 99 Lincheng West Road, Guiyang, 550081 China
CAS Center for Excellence in Quaternary Science and Global Change, Xi'an, 710061 China |
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Abstract: | A LuxI/R-like quorum sensing (QS) system (AfeI/R) has been reported in the acidophilic and chemoautotrophic Acidithiobacillus spp. However, the function of AfeI/R remains unclear because of the difficulties in the genetic manipulation of these bacteria. Here, we constructed different afeI mutants of the sulfur- and iron-oxidizer A. ferrooxidans, identified the N-acyl homoserine lactones (acyl-HSLs) synthesized by AfeI, and determined the regulatory effects of AfeI/R on genes expression, extracellular polymeric substance synthesis, energy metabolism, cell growth and population density of A. ferrooxidans in different energy substrates. Acyl-HSLs-mediated distinct regulation strategies were employed to influence bacterial metabolism and cell growth of A. ferrooxidans cultivated in either sulfur or ferrous iron. Based on these findings, an energy-substrate-dependent regulation mode of AfeI/R in A. ferrooxidans was illuminated that AfeI/R could produce different types of acyl-HSLs and employ specific acyl-HSLs to regulate specific genes in response to different energy substrates. The discovery of the AfeI/R-mediated substrate-dependent regulatory mode expands our knowledge on the function of QS system in the chemoautotrophic sulfur- and ferrous iron-oxidizing bacteria, and provides new insights in understanding energy metabolism modulation, population control, bacteria-driven bioleaching process, and the coevolution between the acidophiles and their acidic habitats. |
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