Regulation of P1 expression by UV-B. (A) P1 transcript analysis was performed by nested RT-PCR in leaves of W23 and maize landraces after an 8 h-UV-B-treatment or under control conditions in the absence of UV-B. The non-UV-B regulated transcript thioredoxin-like transcript was used as a control. (B) Western-blot analysis of nuclear leaf protein extracts of W23 and maize landraces after an 8 h-UV-B-treatment or under control conditions in the absence of UV-B using antibodies against P1. 10 μg of nuclear proteins were loaded in each lane. The relative protein levels obtained from the quantification of the western blot bands by densitometry were compared between UV-B and control conditions. MIS: Mishca; CFT: Confite Puneño; ARR: Arrocillo Amarillo; CCH: Cacahuacintle; CNC: Conico Norteño. All experiments were done in triplicate using biological replicates.