Transcriptional activator (PubMed:26586833). Probable component of the central regulatory system controlling transcriptional responses to Pi starvation (PubMed:26586833). Binds in a sequence-specific manner to phosphate starvation-regulated promoters (PubMed:26586833). Required for female gametophyte development and function (PubMed:15634699). Homo- and heterodimers (PubMed:26586833). Interacts with PHL2, but not with PHR1 (PubMed:26586833). Up-regulated in roots by low Pi. Embryo lethal. Belongs to the MYB-CC family. Intron retention.