Zingone A. , Biffali E., Forlani G., Natale F., Sarno D.
Stazione Zoologica 'A. Dohrn', Naples, Italy
An investigation on Micromonas pusilla virus has been started to assess the role of viral infection in the seasonal pattern of this species in the Gulf of Naples. The virus and its host have been quantified weekly at a coastal station around the spring bloom time over three consecutive years, using a serial dilution technique and epifluorescence microscopy, respectively. In some cases, we have observed that virus concentration increases once the host has attained a threshold concentration, whereas in other cases no relationships can be tracked.
A viral strain isolated from the gulf, MpV N1, was used to investigate virus-algal relationship. Recovery after massive lysis was often observed in infected cultures, which showed resistance to further infections with MpV N1. Resistance to MpV N1 was also observed in algal strains not previously infected in the lab. Southern Blot hybridization did not reveal the presence of viral genome in recovered M. pusilla DNA. The presence and relative importance of resistant strains in the natural environment should be assessed in order to understand the role of virus in the seasonal pattern of the species.