New approach for papaya latex storage without virus degradation

Papaya meleira virus (PMeV) is the causal agent of papaya (Carica papaya L.) sticky disease, which has been detected through analysis of its double-stranded RNA (dsRNA) genome from plant latex. In this work we demonstrate that PMeV dsRNA is protected during 25 days when latex is diluted in citrate buffer pH 5.0 (1:1 v/v) and maintained at -20ºC. At the same temperature, some protection was observed for pure latex or latex diluted in ultra-pure water. Conversely, the dsRNA was almost completely degraded after 25 days when maintained at 25ºC, indicating the need for freezing. The proper procedures to collect and store papaya latex described here will contribute to efficient and large scale use of molecular diagnosis of PMeV.