Potatoes are developed vegetatively from tubers, and therefore potato virus transmission is always a possibility. The potato leafroll virus (PLRV) is a highly devastating virus of the genus Polerovirus and family Luteoviridae and is regarded as the second-most destructive virus after Potato virus Y. Multiple species of aphids are responsible for the persistent and non-propagating transmission of PLRV. Due to intrinsic tuber damage (net necrosis), the yield and quality are drastically diminished. PLRV is mostly found in phloem cells and in extremely low amounts. Therefore, we have attempted to detect PLRV in both potato tuber and leaves using a highly sensitive, reliable and cheap method of one-step reverse transcription-recombinase polymerase amplification (RT-RPA). In this study, an isothermal amplification and detection approach was used for efficient results. Out of the three tested primer sets, one efficiently amplified a 153-bp product based on the coat protein gene. In the present study, there was no cross-reactivity with other potato viruses and the optimal amplification reaction time was thirty minutes. The products of RT-RPA were amplified at a temperature between 38 and 42 °C using a simple heating block/water bath. The present developed protocol of one-step RT-RPA was reported to be highly sensitive for both leaves and tuber tissues equally in comparison to the conventional reverse transcription-polymerase chain reaction (RT-PCR) method. By using template RNA extracted employing a cellular disc paper-based extraction procedure, the method was not only simplified but it detected the virus as effectively as purified total RNA. The simplified one-step RT-RPA test was proven to be successful by detecting PLRV in 129 samples of various potato cultivars (each consisting of leaves and tubers). According to our knowledge, this is the first report of a one-step RT-RPA performed using simple RNA extracted from cellular disc paper that is equally sensitive and specific for detecting PLRV in potatoes. In terms of versatility, durability and the freedom of a highly purified RNA template, the one-step RT-RPA assay exceeds the RT-PCR assay, making it an effective alternative for the certification of planting materials, breeding for virus resistance and disease monitoring.

The present study investigated the relative transmission efficiency of Potato Leaf Roll Virus (PLRV) by two aphid species on potato. Five aviruliferous aphids of both the species were allowed to acquire the PLRV from virus infected potato plant for 96 hrs (Acquisition Access Period) then transferred to oneweek old microplants of variety Kufri Jyoti and allowed to feed for 96 hr (Inoculation Access Period) in order to inoculate the virus. The virus transmission was terminated by spraying imidacloprid 18.5 SL @ 0.03%, and then the plants were incubated for one month at 26±2°C. The plants were tested for the virus presence after the incubation by polymerase chain reaction using coat protein specific primers. The result revealed that both the aphid species had transmitted the PLRV, but the transmission efficiency varied greatly as A. solani could transmit the PLRV with 7.1% efficiency whereas M. persicae transmitted with greater efficiencies (66.6%).