Potato Virus Detection and Epidemiology of Recombinant PVY Strains in Seed Plots through Multiplex RT PCR

Abstract Potato Virus Y(PVY) is the most important virus disease of potato (Solanum tuberosum L.) and ranked fifth in the world’s top ten most important plant viruses. PVY has five common strains and more than ten recombinant strains, derived mostly from a parental lineage of PVYN and PVYO. In Ireland, the recombinant strains PVYNTN, PVYN:O, and PVYNWi are more prevalent, which accounts for more than 90% of the PVY infections. The Teagasc potato breeding program produces seed lots in yearly trials and advanced clones are exported for further trials abroad. These clones must meet seed potato certification standards, and as many of the new recombinant strains of PVY induces mild symptoms, visual inspection is not always adequate and laboratory diagnosis is used to determine PVY infection. This study was conducted to identify, and symptom characterize the old and recombinant strains of PVY in the Teagasc breeding programs of potato in Oak Park. It was conducted through multiplex RT PCR and compared with the captured and categorized pictures of the symptoms. Moreover, the methodologies used in the Center for extraction of crude samples and the results of ELISA and RT PCR were compared. The results that were obtained from RT PCR on detection of PVY, PVS, and PVA, were found to be more sensitive than the ELISA technique. The recombinant strains PVYNTNa, PVYNTNb, and SYR III were found to be the more prevalent in the field. Moderate mosaic symptoms were observed to be common in most of the plants. PVYNTNa was found associated with mild to moderate mosaic; whereas SYR III was linked with moderate to severe mosaic and crinkling of the leaves. The identified recombinant strains further confirm the previous studies on their prevalence in Ireland. This study is the first to report the prevalence of SYR III recombinant strain in Ireland. Though the study was conducted on a small scale, the symptoms observed, and their associated links with the strains give a preliminary result for better management in the field. Moreover, the results give a strong starting point for understanding the symptomology associated with different PVY strains to support further in-depth study of the relationship between the strains, varieties and the symptoms. Finally, a genotyping of the SYR III recombinant strain of PVY reported in this study and wider study on its distribution in Ireland is recommended.