FIG 6.
Effect of bacterial communities on the light tolerance of cultured Symbiodiniaceae. Maximum quantum yield of photosystem II (PSII) (variable fluorescence divided by maximum fluorescence [Fv/Fm]) in cultured Symbiodiniaceae under non-stressful lighting (24°C, 50 μmol photons m−2 s−1) and stressful lighting (24°C, 400 μmol photons m−2 s−1). To analyze the effects of light stress on dinoflagellate cells, we compared the Fv/Fm of NIES-4077 and Abx-4077 cells under stressful and non-stressful lighting at the same time. All data are given as means ± standard error of the mean (n = 3). Statistical analysis was conducted using one-way analysis of variance followed by Tukey’s post hoc test for multiple-comparison tests. P values less than 0.05 were considered significant. Significant differences are represented by different letters. Colors of letters correspond to each sample (gray; Abx-4077 [Control], red; Abx-4077 [light stress], black; NIES-4077 [Control], yellow; NIES-4077 [light stress]). Abx-4077 was dominated by sequences affiliated with Maribacter, with a mean abundance of 100%, which had a relative mean abundance of 1.2% in the parent culture of NIES-4077.