ARF5/MONOPTEROS directly regulates miR390 expression in the Arabidopsis thaliana primary root meristem (Plant Direct)

Previous studies have indicated that auxin controls gene expression via regulatory transcriptional networks, mediated by a family of DNA-binding auxin response factors (ARFs) that bind to auxin response DNA elements (AuxREs) in the promoters of genes. In this study, Dastidar et al. investigated the localization of the microRNA miR390 expression and how it is regulated in response to auxin at the root meristem in Arabidopsis. After the analysis of mutants using transcriptional reporters and ChIP-qPCR assays, the authors localized miR390 expression in the in “the transit‐amplifying compartment of the root meristem where it modulates response to exogenous auxin”. The results show a single enhancer and an specific AuxRE in the miR390 promoter responsible for its expression in this region and identify ARF5/MONOPTEROS as an upstream regulator of miR390, interacting directly with this enhancer via the AuxRE. Studying the signalling circuits of the miR390 network is important to understand the foundations of morphological diversity in plants. (Summary by Ana Valladares) Plant Direct 10.1002/pld3.116