Lateral Flow Immunoassay for Rapid Diagnosis of Potato Blackleg Caused by Pectobacterium atrosepticum

Abstract

Potato blackleg and soft rot caused by Pectobacterium atrosepticum lead to significant yield losses. The early detection of P. atrosepticum is essential for healthy potato seed tubers. The aim of this study was to develop a method to rapidly detect P. atrosepticum based on the lateral flow immunoassay (LFIA) technique. Rabbit polyclonal antibodies specific to various strains of P. atrosepticum were obtained. Conjugates of these antibodies with gold nanoparticles averaging 20 nm in diameter were synthesized. Optimal concentrations of antibodies and conjugates deposited on membranes of the test strips were determined. The developed LFIA is suitable for analyzing potato tubers and leaves and has a visual detection limit of 2 × 10 5 cells/mL and a duration time of 10 min. Simple, rapid preparation of samples consists of homogenization in extracting buffer. No cross-reactivities with other potato pathogens, such as Pectobacterium carotovorum subsp. carotovorum and Dickeya dianthicola, or saprophytes of healthy potato plants were detected. The assay was tested on 30 lots of potato tubers. The LFIA results were confirmed by ELISA (100% concurrence) and PCR (87.5% for positive samples and 95.5% for negative samples). Diagnosis of potato blackleg and soft rot by LFIA requires no equipment or training to perform, is cost effective and can be used in the field to monitor infection-causing P. atrosepticum.