The use of quantitative PCR with high resolution melting (qPCR-HRM) analysis to distinguish the Polish mild and yellowing pathotypes of Pepino mosaic virus (PepMV)

Pepino mosaic virus (PepMV) is a highly infectious virus causing significant losses in tomato greenhouse production worldwide. One of the characteristic symptoms is yellowing discolorations of leaf blades, which is often accompanied by damage of the fruits. It has been found that, two independent point mutations in the gene encoding the coat protein (CP) are responsible for the formation of yellowing symptoms: G463AA/A463AA (155 aa) and GA497U/GG497U (166 aa), respectively. In our study, qPCR-HRM was used to distinguish mild and yellowing pathotypes. Appropriate primers, amplifying a fragment of the CP-encoding gene in which both yellowing mutations are located were designed. The analysis was carried out using 18 isolates originated from greenhouses in different region of Poland. Our experiments confirmed the effectiveness of the designed primers to differentiate the analyzed pathotypes. This technique is a valuable tool for detecting the diversity of PepMV.