Rapid and visual detection of milk vetch dwarf virus using recombinase polymerase amplification combined with lateral flow strips

Background: Milk vetch dwarf virus (MDV) is an important ssDNA virus which causes yellowing, stunting and leaf rolling symptoms on legumes. In China, the virus causes great economic losses and has recently been found to infect tobacco. The expansion of its host range and its ability to spread rapidly has given rise to the urgent need for a sensitive, specific and rapid diagnostic assay that can assist in effective disease control.

Methods: Assays based on the polymerase chain reaction combined with lateral flow strip detection (PCR-LFS) and recombinase polymerase amplification combined with LFS (RPA-LFS) were developed targeting the coat protein (CP) gene of MDV.

Results: The PCR and RPA assays could detect respectively 10³ copies or 10¹ copies of MDV by agarose gel electrophoresis. The PCR-LFS and RPA-LFS assays developed could both detect as few as 10¹ copies per reaction at 37 °C. Both methods could detect MDV in crude leaf extracts.

Conclusions: The RPA-LFS assay developed is a rapid, sensitive and specific method for detecting MDV, which is convenient and has great potential for use in the field.

Keywords: Lateral flow strips; Milk vetch dwarf virus; Polymerase chain reaction; Rapid and visual detection; Recombinase polymerase amplification.