Transcriptional activator that binds to the SBP-box DNA core binding motif 5'-GTAC-3' (PubMed:24170127). Can target the TCP motif 5'-TGGGCC/T-3' through interaction with PCF1 and PCF2 (PubMed:24170127). Key regulator of the plant architecture that controls shoot branching and panicle development (PubMed:20495565, PubMed:20495564, PubMed:22960246). Promotes panicle branching (PubMed:20495565, PubMed:20495564, PubMed:22960246, PubMed:26519999). Promotes high grain yield (PubMed:20495565, PubMed:20495564, PubMed:26519999). Binds to the promoters of TB1 and DEP1 (PubMed:24170127). Suppresses rice tillering mainly through positive regulation of TB1 (PubMed:24170127). Regulates plant height and panicle length through positive regulation of DEP1 (PubMed:24170127). Repressed by D53 in strigolactone (SL) signaling (PubMed:28809396). Acts with D53 to mediate the SL-regulated tiller development (PubMed:28809396). Functions as a direct downstream component of D53 in regulating tiller number and SL-induced gene expression (PubMed:28809396). Binds directly to the D53 promoter and plays a critical role in the negative feedback regulation of SL-induced D53 expression (PubMed:28809396). Involved in defense response against pathogens (PubMed:30190406, PubMed:30886331). Phosphorylated at Ser-163 in response to infection by the fungal pathogen Magnaporthe oryzae (PubMed:30190406). Phosphorylation reduces SPL14/IPA1 binding to the GTAC site in the DEP1 promoter and enhances binding to the TGGGCC site in the WRKY45 promoter (PubMed:30190406). Binding to the promoter of the pathogen defense gene WRKY45 activates its expression, leading to enhanced disease resistance (PubMed:30190406). Reduces gibberellin-mediated disease susceptibility by stabilizing SLR1 (PubMed:30886331). Possesses transactivation activity in yeast cells (PubMed:20495564). Interacts with PCF1 and PCF2 (PubMed:24170127). Interacts with IPI1 (PubMed:28298520). Interacts with D53 (PubMed:28809396). Interacts with SLR1 (PubMed:30886331). Interacts (via C-terminus) with SHI1 (PubMed:30914468). Expressed in young panicles (PubMed:16861571). Expressed in the shoot apex at both the vegetative and reproductive stages (PubMed:20495565, PubMed:20495564, PubMed:22960246). Highly expressed in the promordia of primary and secondary branches (PubMed:20495565, PubMed:22960246). Highly expressed in young panicles (PubMed:20495564). Negatively regulated by microRNA miR156. The SBP-type zinc finger is required for the binding to DNA. Phosphorylated at Ser-163 in response to infection by the fungal pathogen Magnaporthe oryzae. Ubiquitinated by IPI1, which leads to proteasomal degradation. Plants overexpressing SPL14/IPA1 exhibit enhanced disease resistance against the bacterial pathogen Xanthomonas oryzae pv oryzae (Xoo), and increased grain yield.