Ambient temperature perception in papaya for papaya ringspot virus interaction.

Temperature dramatically affects the host-virus interaction. Outbreaks of viral diseases are frequently associated with the ambient temperature required for host development. Using papaya as a host and Papaya ringspot virus (PRSV) as a pathogen, we studied the effect of temperature on the intensity of disease symptoms and virus accumulation. The phenotypic expression of symptoms and viral accumulation were found to be maximum at ambient temperature (26-31 degrees C) of papaya cultivation. However, there was a drastic difference, 10 degrees C above and below the ambient temperature. The underlying mechanism of these well-known observations are not yet understood completely; however, these observations might help find answers in RNA silencing mechanism of plants. Since viral-derived silencing suppressor proteins play a significant role in RNA silencing mechanism, here we show that PRSV-derived Helper component proteinase (HC-Pro) protein has an affinity for small RNAs in a temperature-dependent manner. This suggested the probable role of HC-Pro in the temperature-regulated host-virus relationship.