5.6. Reintroduction of Bacteria in T. rotula FE80 Cultures

The axenic T. rotula FE80 culture was provided by CNR-ICB (Pozzuoli, NA, Italy) laboratory. A total of 100 μL of FL bacteria prepared from a xenic S. marinoi FE7 culture and stored in a cryovial with 40% glycerol were inoculated in a 30 mL axenic T. rotula FE80 culture at exponential growth phase. The culture was maintained at a temperature of 20 °C, at 12:12 h light:dark cycle, and with a photon flux of 100 μmol photons m² s⁻¹ for 3 days, which was then refreshed by a 1:30 dilution with fresh F/2 medium. When stabilized, the culture was refreshed weekly in the same manner and the presence of the bacteria was periodically checked with PCR on the SA-FL fraction gDNA preparations (see “DNA extraction, primer design and PCR” paragraph for details).