Transcriptional activator (PubMed:26586833). Acts redundantly with PHR1 as a key 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). Homo- and heterodimers (PubMed:26586833). Interacts with PHL3, but not with PHR1 (PubMed:26586833). Up-regulated in roots by low Pi. Belongs to the MYB-CC family.