Thermally driven death-melting curve analysis for rapid and straightforward identification of bacteria

• For the first time, SYBR Green was used to trace the death dynamic of bacteria. • Two biological processes (dead and melting) were found to be ubiquitous in bacteria. • A death-melting curve analysis method was put forward for bacterial identification. • The as-developed method was successfully used for the rapid mapping of soil bacteria. Bacterial identification remains pivotal for biological research, food safety control, clinical diagnosis and effective treatment. Generally, 16S rRNA-based sequencing and antibody-based immunoassay are used to identify bacteria; however, both of them are time-consuming and expensive. Herein, we put forward a thermally driven death-melting curve analysis (DMCA) method to identify bacteria rapidly. In the method, SYBR Green I and a fluorescent reader with heating models were used to trace both the biomembrane integrity (viability) and dsDNA of the bacteria. During the heating-up of the bacteria from 37 to 98 °C, the fluorescent microplate reader was able to record the death curves of the bacteria and melting curves of the dsDNA in the bacteria. Different bacteria showed noticeable differences in thermostability and dsDNA component, allowing possible identification of these bacteria through Pearson Correlation analysis or dimension reduction analysis of the death-melting curves. By using nine bacterial strains as a proof-of-concept model, clear identification between the bacteria was accomplished without use of antibodies. The DMCA was successfully employed for the mapping of soil single-cell derived bacteria, the result of which was partly in agreement with that of the 16s RNA-based sequencing. Thus, our study provides a rapid, high-throughput, and low-cost approach for bacteria identification, and we believe it would have many potential applications in bacteriological research.