Abstract:

【Objective】The aim of this study was to build rapid and accurate detection and quantification of R. solanacearum and study the interaction between bacterial and its host. 【Method】 In this study, real time quantitative PCR (RTQ-PCR) targeting the hrpB was developed for the quantification of bacteria load and the method was used to analyze the bacterial population dynamics in peanut after R. solanacearum inoculation.【Result】The results demonstrated that both the extracted DNA and whole cell of R. solanacearum could be used as template for bacterial quantification. Without enrichment step, the detection limit of the method using whole cell as template was 103 CFU/mL, the liner range was in 103-108 CFU/mL, the established RTQ-PCR method could be used for R. solanacearum quantification but the calculated number was about 1.5-fold compared with the traditional plating method. The application of the method in peanut suggested that 3-5 d post inoculation is of vital importance for peanut and R. solanacearum interaction and the node site in peanut may play a role in restriction of bacterial proliferation.【Conclusion】 RTQ-PCR is a simple, rapid and high throughput method developed for R. solanacearum quantification.

Key words: Ralstonia solanacearum, real time quantitative PCR, bacterial load, peanut, hrpB