FIG 5.
RT-PCR showing relative expression levels of secondary metabolite biosynthesis genes mcyA (microcystin; A), mcnB (cyanopeptolin; B), mcaE (microcyclamide; C), aerJ (aeruginosin; D), and IPF47 (PKSI/PKSIII biosynthesis, presumably aromatic polyketide; E) in WT PCC 7806 and the ΔmcyB mutant (MT) without (co) and with (mc) MC-LR treatment under conditions of darkness (D; 0 μE m−2 s−1), low light (LL; 16 μE m−2 s−1), and high light (HL; 70 μE m−2 s−1). Expression rates were calculated as ratios to WT-LL-co levels. Statistical testing is indicated by error bars, representing standard errors, while the significance of MC-LR addition in relation to the control samples of the same genotype grown under the same light conditions and analyzed by two-tailed Student's t test is illustrated on respective bars as significantly upregulated (+) and significantly downregulated (−).