Seed transmission of Papaya meleira virus in papaya (Carica papaya) cv. Maradol

Papaya meleira virus (PMeV), the causal agent of papaya sticky disease, was first reported in Brazil and more recently in Mexico. Yield losses in papaya (Carica papaya) orchards related to this virus can be considerable over relatively short time spans. To date, very little is known regarding the transmission mechanisms of PMeV, which has made it difficult to effectively control the virus and to prevent dissemination. A few published reports have claimed that PMeV is not seed-transmissible. However, in this study, evidence is presented for seed transmission of PMeV in papaya cultivar Maradol. Three seed materials (whole dry seed, seed coat and embryo-endosperm) from Maradol were analysed using reverse transcription-polymerase chain reaction. A seed transmission rate of c. 81% was observed, suggesting that this mechanism is an important route of virus dissemination. For the first time, this study shows that PMeV is seedborne and can be transmitted to the next generation through contaminated papaya seeds.