The two-component system CBO2306/CBO2307 is important for cold adaptation of Clostridium botulinum ATCC 3502

• Importance of CBO2306/CBO2307 for cold adaptation of Clostridium botulinum ATCC 3502
• For efficient growth of C. botulinum ATCC 3502 at 15 °C CBO2306/CBO2307 is required.
• The cbo2306 and cbo2307 are upregulated upon cold-shock in C. botulinum ATCC 3502.

Clostridium botulinum is a notorious foodborne pathogen. Its ability to adapt to and grow at low temperatures is of interest for food safety. Two-component systems (TCSs) have been reported to be involved in cold-shock and growth at low temperatures. Here we show the importance of TCS CBO2306/CBO2307 in the cold-shock response of C. botulinum ATCC 3502. The relative expression levels of the cbo2306 and cbo2307 were up to 4.4-fold induced in the cold-shocked cultures but negatively regulated in the late-log and stationary growth phase in relation to early logarithmic growth phase in non-shocked cultures. Importance of the CBO2306/CBO2307 in the cold stress was further demonstrated by impaired growth of insertional cbo2306 or cbo2307 knockout mutants in relation to the wild-type strain ATCC 3502. The results suggest that the TCS CBO2306/CBO2307 is important for cold-shock response and adaptation of C. botulinum ATCC 3502 to low temperature.