Isothermal based rapid and direct detection of bean common mosaic virus (BCMV) from crude plant sap

Bean common mosaic virus (BCMV) is a serious viral pathogen of leguminous crops especially common beans. BCMV is transmitted through infected seeds and can also spread horizontally by aphid vectors in a non-persistent manner. It is highly stable within the embryo of seed that is the major factor contributing for its long-distance dissemination across continents. Therefore, there is an urgent need to develop a reliable, rapid and cost-effective diagnostic method that can facilitate the detection of the virus in seed certification programs and plant quarantine facilities, thereby prevents its further spread. The present study describes an efficient and accurate detection of BCMV by reverse transcriptase-recombinase polymerase amplification (RT-RPA) assay. The primers were designed from highly conserved region of coat protein region. The BCMV-specific primers successfully amplified fragment of the coat protein (CP) gene under isothermal conditions at 37 °C within 20 min. The limit of detection of the developed assay was determined using both purified RNA and crude plant sap extract. In both cases, the assay exhibited higher sensitivity than conventional RT-PCR, enabling the detection of BCMV at lower template concentrations. In addition, specificity of the assay was tested by cross reaction with closely related non-target viruses (bean common mosaic necrosis virus (BCMNV), clover yellow vein virus (ClYVV), soybean mosaic virus (SMV) and cucumber mosaic virus (CMV) BCMNV). The RT-RPA assay accurately distinguished BCMV from other non-target viruses showing comparable specificity with RT-PCR. To enhance the suitability of the assay for resource-limited settings and reduce the overall detection time, the assay was adapted to accurately detect BCMV directly from crude sap.

The online version contains supplementary material available at https://doi.org/10.1007/s13337-026-00985-7.