Screening of Potato Germplasm through ELISA against Potato Virus X (PVX)

Abstract

Ten varieties / lines of potato germplasm were screened out against PVX to find the resistant source. Out of 10, four varieties were susceptible, three moderately susceptible and three were moderately resistant. DAS-ELISA detected the PVX in leaves samples of different Potato varieties. Mechanical transmission produced the local lesion and insect transmission through aphid (Myzus Persicae) was failed due to unknown reasons. th in production after wheat, rice and maize. Pakistan has been divided into eight agro ecological zones for potato production. The main hub for seed production is northern areas from where seed is provided rest of the country (5). In Pakistan, average yield is low as compared to other countries in the world, due to under attack of various pathogens like bacteria, nematode, fungi and viruses (11). Among them viral diseases caused by viruses such as; Potato virus X (PVX), Potato leaf roll virus (PLRV) and Potato virus Y (PVY) are most devastating pathogens prevail in potato field in Pakistan. Losses due to these viruses are upto 83% (10). PVX is widely distributed not only in Pakistan but worldwide with wide host range. It belongs to Potexvirus, family Alphaflexiviridae virus. It is rod shaped, filamentous, monopartite +ve sense ssRNA virus. PVX alone can cause yield loss in the range of 5-20% depending upon the potato genotype, virus strain and the simultaneous infection with other viruses like PVY and PVA (2). The major symptoms of PVX are inter venial mosaic, rugosity, stunting, mottle on upper leaves and small sized tubers. It is also called mild mosaic virus due to mild or no symptom in most potato varieties but has synergistic effect with PVY resulting in severe symptoms. Because of latent infection PVX is difficult to be characterized. PVX is transmitted mechanically. Insect transmission is not known yet. It is immunogenic and easily detected by different serological tests as ELISA and time-resolved fluoroimmunoassay (13). In Pakistan PVX has been reported and detected through ELISA (6). Because of latent nature of PVX, ELISA is a reliable, quick and cheap method for its detection. Insect transmission of PVX is still a question mark. Hence this research was carried out to find out the resistant source from germplasm, its transmission and detection through ELISA.