Agdia, Inc. has commercialized a rapid, user-friendly molecular assay, on their AmplifyRP XRT+ platform, for the detection of Dickeya spp. causing blackleg disease on potato.
Dickeya spp. of bacteria are responsible for numerous plant diseases worldwide, including blackleg disease on potato. The species of bacteria in this genus produce pectolytic enzymes that degrade plant cell walls, liquefying pectin and causing tissue death. Tissue maceration causes the characteristic symptoms of stem necrosis or blackleg on aerial plant parts and wilting. Dickeya spp. are disseminated primarily on latently infected seed tubers; infection courts include tuber surface, the lenticels, and/or the vascular system of the tuber. This group of pathogens is economically important and has been responsible for significant crop losses in North America and Europe.
The AmplifyRP XRT+ assay for detection of Dickeya spp. is an isothermal amplification technology that implements the recombinase polymerase amplification (RPA) platform. This method promotes the rapid amplification and detection of nucleic acid targets (DNA or RNA) via enzymatic reactions, and maintains a single operating temperature of 102 degrees Fahrenheit. The RPA technology provides comparable sensitivity and specificity to polymerase chain reaction (PCR) assays while offering advantages to PCR. Crude plant extracts are processed for RPA, and total assay time is approximately 30 to 40 minutes, including sample preparation. Results can be visualized in quantitative, real-time format using Agdia’s AmpliFire portable fluorometer or as end-point detection in an amplicon detection chamber. Furthermore, RPA does not require expertise in molecular diagnostics to perform.
Agdia says its new assay will detect all species of Dickeya known to be pathogenic on potato, including D. dianthicolaand and D. solani. Furthermore, no cross-reactivity was observed with several potential cross-reactors, including Pectobacterium spp., Erwinia spp., Clavibacter michiganensis subsp. sepedonicus, Ralstonia solanacearum, Candidatus Liberibacter solanacearum, Fusarium spp., and Phytophthora spp. Agdia says its RPA assay for the detection of Dickeya is comparable or superior to all available molecular and serological diagnostics, in sensitivity and specificity. This assay will detect Dickeya spp. in tubers, stem tissue and pure cultures. The introduction of this RPA assay is the third in the last 12 months for Agdia, bringing its total catalog to 13 assays on this platform.
Agdia recommends using the AmpliFire portable fluorometer or the amplicon detection chamber with its AmplifyRP XRT+ products. The AmpliFire is battery-operated and portable, allowing it to be implemented in remote locations. A large, intuitive touchscreen makes workflow simple and straightforward while data export options provide for detailed interface with personal computers. The amplicon detection chamber is used in conjunction with a heat block to visualize end-point results. The lateral flow strip inside the chamber detects dual-labeled amplicons, both DNA and RNA. Amplicon detection chambers are designed to provide reliable amplicon detection while preventing escape and contamination of future assays. The chambers are for single use only. For more information on Agdia’s complete line of AmplifyRP assays, visit www.agdia.com.