An immunochromatographic test strip for on-site detection of Ralstonia solanacearum in tobacco leaves and soil

Tobacco bacterial wilt is one of the most devastating soil-borne diseases in tobacco-producing regions worldwide. It is often responsible for significant economic losses during tobacco production. A rapid, specific, and high-throughput on-site detection method is important for plant disease management. In this study, monoclonal antibody 3H3 and polyclonal antibody 0344 specific for Ralstonia solanacearum were used to prepare a colloidal gold-based immunochromatographic test strip (ITS). Under optimal conditions, the detection limit of the ITS was 10(5) CFU/mL. The ITS was able to detect different R. solanacearum strains collected from Shandong, Yunnan, Guizhou, and Sichuan provinces in China. Moreover, the ITS was highly specific for R. solanacearum, with no cross-reactivity with Alternaria alternata (Fries) Keissler, Pseudomonas syringae pv. angulata, and P. syringae pv. tabaci. Furthermore, R. solanacearum-spiked tobacco leaves and soil were used to evaluate the matrix interference of the developed ITS, which indicated the test strip was unaffected by leaf size or soil abundance.