TEMPRANILLO is a direct repressor of the microRNA miR172

Summary In the age‐dependent pathway, micro RNA 156 (miR156) is essential for the correct timing of developmental transitions. miR156 negatively regulates several SPL genes, which promote the juvenile‐to‐adult and floral transitions in part through upregulation of miR172. The transcriptional repressors TEMPRANILLO 1 ( TEM 1) and TEM 2 delay flowering in Arabidopsis thaliana at least through direct repression of FLOWERING LOCUS T ( FT ) and gibberellin biosynthetic genes, and have also been reported to participate in the length of the juvenile phase. Levels of TEM mRNA and miR156 decrease gradually, allowing progression through developmental phases. Given these similarities, we hypothesized that TEM s and the miR156/ SPL /miR172 module could act through a common genetic pathway. We analyzed the effect of TEM s on levels of miR156, SPL and miR172, tested binding of TEM s to these genes using chromatin immunoprecipitation and analyzed the genetic interaction between TEM s and miR172. We found that TEM s played a stronger role in the floral transition than in the juvenile‐to‐adult transition. TEM 1 repressed MIR 172A , MIR 172B and MIR 172C expressions and bound in vivo to at least MIR 172C sequences. Genetic analyses indicated that TEM s affect the regulation of developmental timing through miR172.