Occurrence and Incidence of Major Potato Viruses in Bangladesh and their Molecular Detection

Incidence of major potato viruses in eight major potato growing areas of Bangladesh, viz. Panchagarh, Thakurgaon, Nilphamari, Rangpur, Bogra, Chapainawabgonj, Pabna and Munshiganj were investigated in field samples. Overall, three upazilla (sub-districts) from each district (which were at least 20 km apart) were selected for samples collection and disease incidence monitoring. A total of 240 samples were collected on the basis of virus and viral like symptoms. Collected samples were storage at 40C and analyzed in Molecular Biology and Plant Virology lab, Central Research Laboratory of Sher-e-Bangla Agricultural University (SAU), Dhaka. Enzyme Linked Immunosorbent Assay (ELISA) tests revealed that Potato leaf roll virus (PLRV) was most predominant virus followed by Potato virus Y (PVY) and Potato virus X (PVX). During the year 2017-18, the relative frequency of infection by PLRV and PVY was 31 and 2% of infected samples respectively. Single, double and triple infections were 34, 45 and 2.0% respectively. Infection of detected potato viruses in all investigated districts with different percentage was almost similar. Major potato viruses' symptoms that appear at investigated areas are PLRV, PVY and PVX and their relative incidences level in random samples were severe to moderate. In all investigated areas, PLRV and PVY appeared in severe to moderate level and their % incidence was (18 & 41%) and (3 & 17%) respectively, while the PVX was appeared in moderate level and % incidence of PVX 18%. In this study, the sources of potato seed tubers was also studied and observed that in most of the cases farmers of selected areas are using continuously same field and used their own seed tubers that was kept in cold storage condition and % frequency was 67.6%. PLRV and PVY were also detected via reverse transcriptase polymerase chain reaction (RT-PCR). A 346 bp and 480 bp amplicon of PLRV and PVY- coat protein (CP) gene was amplified and the nucleotide sequences of amplified.