Photosynthetic responses and growth performance of virus-infected and noninfected Ectocarpus siliculosus (Phaeophyceae)

The marine brown alga Ectocarpus siliculosus (Dillwyn) Lyngbye can be infected by a double-stranded DNA virus, which is expressed tit the reproductive structures of the hose thalli. The rates of photosynthetic oxygen evolution in infected and uninfected gametophytes and sporophytes were measured at different carbon concentrations to assess a possible detrimental effect of the virus infection. No significant differences were found in photosynthetic and respiratory rates. In addition, biomass production by infected thalli was similar to that of uninfected parent culture. SDS-PAGE protein analysis of infected and uninfected thalli showed no differences in the proteins produced or in the amount of ribulose bisphosphate carboxylase/oxygenase. the key enzyme for CO2 fixation, that was present.