Towards understanding the mechanism of n-hexane tolerance in Synechocystis sp. PCC 6803

Abstract

Synthetic biology efforts have also led to the development of photosynthetic cyanobacteria as “autotrophic cell factories” for biosynthesis of various biofuels directly from CO2. However, the low tolerance to toxicity of biofuels has restricted the economic application of cyanobacterial hosts. In this study, RNA-seq transcriptomics was employed to reveal stress responses to exogenous n-hexane in Synechocystis sp. PCC 6803. Functional enrichment analysis of the transcriptomic data showed that signal transduction systems were induced significantly. To further identify regulatory genes related to n-hexane tolerance, a library of transcriptional regulators (TRs) deletion mutants was then screened for their roles in n-hexane tolerance. The results showed that a knockout mutant of slr0724 that encodes an HtaR suppressor protein was more tolerant to n-hexane than the wild type, indicating the involvement of slr0724 in n-hexane tolerance. This study provides the foundation for better understanding the cellular responses to n-hexane in Synechocystis sp. PCC 6803, which could contribute to the further engineering of n-hexane tolerance in cyanobacteria.