Using QPCR, we examined the mRNA expression levels of pebA, psbB and psaE genes in Synechococcus sp. Over 8 days of culture under different light sources (Fig. 3). In all of the experimental groups, the transcript levels significantly increased during the period of cultivation relative to that at day 8 of cultivation. Additionally, the mRNA expression levels of the pebA and psbB genes were significantly higher in the blue and green LED groups compared to those in the other groups (Figs. 3A and 3B). The psaE mRNA expression level, however, was significantly