Rapid and specific detection of Pentastiridius leporinus by recombinase polymerase amplification assay.

Pentastiridius leporinus (Hemiptera: Cixiidae) is the main vector of an emerging and fast spreading sugar beet disease, the syndrome 'basses richesses' (SBR), in different European countries. The disease is caused by the γ-3-proteobacterium 'Candidatus Arsenophonus phytopathogenicus' and the phytoplasma 'Candidatus Phytoplasma solani' which are exclusively transmitted by planthoppers and can lead to a significant loss of sugar content and yield. Monitoring of this insect vector is important for disease management. However, the morphological identification is time consuming and challenging as two additional cixiid species Reptalus quinquecostatus and Hyalesthes obsoletus with a very close morphology have been reported in sugar beet fields. Further, identification of females and nymphs of P. leporinus at species level based on taxonomic key is not possible. In this study, an isothermal nucleic acid amplification based on recombinase polymerase amplification (RPA) was developed to specifically detect P. leporinus. In addition, real-time RPA was developed to detect both adults (male and female) and nymph stages using pure or crude nucleic acid extracts. The sensitivity of the real-time RPA for detection of P. leporinus was comparable to real-time PCR, but a shorter time (< 7 min) was required. This is a first report for real-time RPA application for P. leporinus detection using crude nucleic acid templates which can be applied for fast and specific detection of this vector in the field.