Transcriptional regulator essential for Nod-factor-induced gene expression (Probable) (PubMed:17244637, PubMed:17071642). Acts downstream of calcium spiking and a calcium/calmodulin-dependent protein kinase required for activation of early nodulation gene expression (PubMed:17244637, PubMed:17071642, PubMed:24329948). Transcription factor involved in the induction of NIN and ENOD40 genes, which are required for rhizobial infection and early nodule development (PubMed:17244637). Does not seem to contribute to the early steps of the arbuscular mycorrhizal fungus infection and colonization processes in roots (PubMed:23926062). Transcription factor involved in the positive regulation of the beta-carotene isomerase D27, which participates in a pathway leading to biosynthesis of strigolactones in roots (PubMed:23926062). Interacts with IPN2 (PubMed:24400899). Binds to RAD1 (PubMed:25560877). Interacts with RAM1 (By similarity). Mainly localized to the nuclear envelope. Also found in the endoplasmic reticulum. Upon Nod-factor application, the nuclear envelope localization disappears and the protein accumulates in the nucleus. Highly expressed in roots. Induced in roots after inoculation with Mesorhizobium loti (PubMed:17071642). Down-regulated in developmentally young regions of roots after inoculation with Mesorhizobium loti (PubMed:23335614). Roots of knockout plants form very few aborted and non-functional nodules under nitrogen limitation when inoculated with Mesorhizobium loti. Belongs to the GRAS family.