Study on the adaptive changes of a hyperthermophilic archaeon Thermococcus onnurineus NA1 under long-term selection on carbon monoxide

Abstract

Adaptive laboratory evolution is one of engineering approaches to produce new and fit phenotypes by long-term selection under a defined condition. To understand the molecular mechanisms driving adaptive phenotypic change, systems-level analysis such as comparative whole-genome sequencing and polyomic analysis has been performed. In this study, we evolved a hyperthermophilic archaeon Thermococcus onnurineus NA1 through serial transfers of a culture to fresh medium with carbon monoxide (CO) over 100 times. The changes in phenotype, genome sequence and transcriptome were analyzed. The growth rate, CO consumption rate and H2 production rate of the strain were gradually increased as the transfer-time increased. The genome of the evolved mutant was sequenced and several mutations were identified in comparison with the parent strain. The gene expression pattern analyzed by transcriptome analysis was consistent with the phenotypic changes, and some genes involved in CO utilization such as carbon monoxide dehydrogenase, hydrogenase, Na+/H+ antiporter and ATP synthetase were significantly upregulated along with the adaption. This is the first report to demonstrate that adaptive evolution is a valuable method to improve a strain utilizing CO.ysis such as comparative whole-genome sequencing and polyomic analysis has been performed. In this study, we evolved a hyperthermophilic archaeon Thermococcus onnurineus NA1 through serial transfers of a culture to fresh medium with carbon monoxide (CO) over 100 times. The changes in phenotype, genome sequence and transcriptome were analyzed. The growth rate, CO consumption rate and H2 production rate of the strain were gradually increased as the transfer-time increased. The genome of the evolved mutant was sequenced and several mutations were identified in comparison with the parent strain. The gene expression pattern analyzed by transcriptome analysis was consistent with the phenotypic changes, and some genes involved in CO utilization such as carbon monoxide dehydrogenase, hydrogenase, Na+/H+ antiporter and ATP synthetase were significantly upregulated along with the adaption. This is the first report to demonstrate that adaptive evolution is a valuable method to improve a strain utilizing CO.