Abstract: Bacterial soft rot of banana，caused by Dickeya spp.，is a destructive disease on banana
discovered recently in Guangdong，China. Establishment and application of detection method is an
important means to prevent the disease from spreading and occuring. A real-time fluorescent PCR assay
was developed based on the universal primers for detecting Dickeya spp. from infectious banana plants and
soil. The results showed that the lowest detection limits for the Plasmid DNA and bacterial suspensions of
bacterial isolate（XJ8-3-3）was 2.4 × 10^-5 ng · μL^-1，and 4.0 × 10² cfu · mL^-1，respectively，by the optimized
real-time fluorescent PCR system，which indicated that detection sensitivity with real-time fluorescent
PCR was at least hundred times higher than that with conventional PCR. The bacterial DNA of XJ8-3-3 in
the infected banana plant tissues and soil could be accurately and rapidly identified by the developed
detection system. The detection limit of bacterial DNA from the soil inoculated with different
concentrations of XJ8-3-3 suspensions，was 0.35 pg · μL^-1 per reaction in real-time quantitative PCR. In
conclusion，this real-time PCR method could be utilized to assist in the implementation of quarantine
measures for prevention and control of the bacterial soft rot of banana caused by Dickeya spp.

Key words: banana, bacterial soft rot, real-time fluorescent PCR, detection