Detection of episomal banana streak Mysore virus by reverse transcription-recombinase polymerase amplification assay

Banana streak viruses (BSVs) are considered a major constraint to banana production worldwide. The integrated BSV sequence in the banana genome makes the nucleo-based detection unreliable and the serological-based methods require high quality polyclonal antiserum. In this study, reverse transcription-recombinase polymerase amplification (RT-RPA) assay was developed for a specific amplification of episomal banana streak Mysore virus (BSMYV) in different banana cultivars. A total of 50 symptomatic and asymptomatic leaf samples of different banana cultivars were evaluated and BSMYV was efficiently detected by RT-RPA using a crude leaf sap template. Similar results were obtained with conventional reverse transcription-polymerase chain reaction (RT-PCR) using purified RNA as template. RT-RPA was significantly faster than RT-PCR with results obtained in less than one hour. The rapid and reliable diagnosis of episomal BSMYV will be most useful for virus indexing in plants including the banana tissue culture certification programme.