Plant virus can enhance its transmission by altering the settling preference of its vector. Nevertheless, most of the studies have focused on the spread of one virus in a field whereas often times there are more than single virus infecting same crop. Furthermore, mixed-infection of multiple viruses tends to cause more severe virus symptoms and changes vector’s biology and behavior different than singular infection. Thus, we are currently investigating the spatial transmission pattern of persistently transmitted potato leafroll virus and non-persistently transmitted potato virus y. However, due to impracticability of obtaining empirical data, we are programming an individual-based modelling software while taking biology of potato, biology and behavior of aphid and different characteristics of two viruses into consideration.

Potato Virus Y (PVY) (Potyviridae: potyvirus) is one of the serious emerging virus of seed potato world-wide. It affects the seed potato by transmitting non-persistently via aphids. Here, we developed a simple PVY detection method which used the boiling technique for releasing of the viral RNA from aphid such as stylet and amplification by PVY specific primers located in the viral coat protein gene which suitable for various strains. This simplified method could save the time compared to earlier detection method due to the simplified RNA extraction step. Following this procedure, we tested this one step RT-PCR based PVY detection method by using three PVY vectoring aphid species (M. persicae, A. gossypii and M. euphorbiae) as well as other sucking type insect such as thrips (F. occidentalis). This PVY detection method is rapid, easy-to-use and suitable for large-scale testing in laboratories of seed potato.

PVY (Potyviridae: potyvirus) is one of the most important potato virus affecting seed potato production and also it is transmitted non-persistently via aphids. For healthy seed potato production, a virus detection system is highly important in addition to aphid monitoring and control. To achieve this detection method, it need to fast and easy to use. About two decades ago RT-PCR based PVY detection method was developed. However that was very time consuming and has low sensitivity. Here, we developed an advanced PVY detection method which a uses the boiling extraction of the viral RNA from aphid stylet and amplification by specific primers located in the viral capsid protein gene. Therefore, it could directly synthesize cDNA of PVY viral capsid gene from extracted RNA of PVY using one-step RT-PCR method in very short time compared to previous methods due to the omission of RNA extraction step. We confirmed this PVY detection method using the two aphid species (Macrosiphum euphorbiae and Aphis gossypii) that known as PVY vectors. The efficiency of this PVY detection method was 60% to 80% from two the aphid species. Hence, this method could be potentially applied to virus free seed potato production programs.

잎담배 4품종 (NC2326, NC95, NC744, Havana)과 2종의 식물 (Nicotiana repanda Wild., Physalis floridana Rydb.)을 이용하여 감자 또는 잎담배에서 분리된 10가지의 감자바이러스 Y (PVY) 계통 판별을 시도하였다. 10가지의 PVY 계통들을 이 식물들에 접종했을 때 괴저, 엽맥녹대 또는 mottling, 무병징등을 나타내면서 서로 다른 기주반응을 보여 쉽게 구분할 수 있었다. 조사된 계통들 중에 PVY-VN, PVY-N, PVY-NSNR, PVY-Chile 및 PVY-Argentina 등은 잎담배 품종 NC2326에서 괴저병징을 나타냈으며 이외 계통들은 엽맥녹대 또는 mottling 병징을 나타냈다. NC95에서는 PVY-MSMR에 의해 괴저병징을 이 외 계통들에 의해서는 엽맥녹대 또는 mottling 병징을 나타냈다. Havana에서는 PVY-NSNR, PVY-MSNR, PVY-VB 등에 의해 nettling 병징을, PVY-Chile 및 PVY-Argentina에 의해 괴저병징을 나타냈으나 이 외의 계통들에 의해서는 병징이 나타나지 않았다. NC744에서는 PVY-MSNR, PVY-MSMR에 의해 mottling 병징을, PVY-Chi 및 PVY-Argentina에 의해 괴저병징을 나타냈으며 이 외의 계통들에 의해서는 병징을 나타내지 않았다. N. repanda에서는 PVY-Argentina에 의해 괴저 반응을, PVY-VN 및 PVY-C에 의해서는 병징을 나타내지 않았으며 이 외의 계통들에 의해서는 mottling 병징을 나타냈다.

Potato virus Y (PVY) and potato leafroll virus (PLRV) are among the most damaging potato viruses and prevalent in most potato growing areas. In this study, cryopreservation was used to eradicate PVY and PLRV using two cryogenic methods. Potato shoot tips proliferated in vitro were cryopreserved through droplet-vitrification and encapsulation-vitrification using plant vitrification solution 2 (PVS2; 30% glycerol + 15% dimethyl sulfoxide + 15.0% ethylene glycol + 13.7% sucrose) and modified PVS2. Both cryogenic procedures produced similar rates of survival and regrowth, which were lower than those from shoot tip culture alone. The health status of plantlets regenerated from shoot tip culture alone and cryopreservation was checked by reverse transcription-polymerase chain reaction. The frequency of virus-free plants regenerated directly from highly proliferating shoot tips reached 42.3% and 48.6% for PVY and PLRV, respectively. In comparison, the frequency of PVY and PLRV eradication after cryopreservation was 91.3~99.7% following shoot-tip culture. The highest cryopreserved shoot tip regeneration rate was observed when shoot tips were 1.0~1.5 mm in length, but virus eradication rates were very similar (96.4~99.7%), regardless of shoot tip size. This efficient cryotherapy protocol developed to eliminate viruses can also be used to prepare potato material for safe long-term preservation and the production of virus-free plants.