Luciferase activity in transformed B73, W23 and Mishca protoplasts. Protoplasts were isolated from etiolated maize leaves from B73, W23 and Mishca (MIS) genotypes. P1 promoter fusions (~1.1kbp upstream +1) from W23 and Mishca were fused to the reporter gene Luciferase (pP1MIS::LUC and pP1W23::LUC, respectively), and protoplasts were transformed with the different constructs using Renilla luciferase vector as transformation control. Samples were then irradiated (UV- B) or not (control) during 8 h, and the luminescence of each sample was determined. The means of the results obtained from biological triplicates are shown; the error bars indicate the SDs of the samples. Asterisks denote statistical differences applying Student’s t test (P < 0.05).