Probable transcription factor (By similarity). Involved in spikelet transition (Probable). Together with IDS1, controls synergistically inflorescence architecture and floral meristem establishment via the regulation of spatio-temporal expression of B- and E-function floral organ identity genes in the lodicules and of spikelet meristem genes (PubMed:22003982). Prevents lemma and palea elongation as well as grain growth (PubMed:28066457). Regulates the transition from spikelet meristem to floral meristem, spikelet meristem determinancy and the floral organ development (PubMed:17144896). May form homodimer (By similarity). Interacts with TPR2/ASP1 (PubMed:26631749). Highly expressed in seedlings and developing panicles (PubMed:17144896, PubMed:20017947, PubMed:22003982). Mostly expressed in newly emerging spikelet meristems and, at low levels, in shoots, roots, panicles, mature spikelets and sheaths (PubMed:17144896). First detected in the boundary region of the shoot apical meristem (SAM) and the surrounding sheath. Expressed at low levels in vegetative organs, mostly in the sheaths. In inflorescence tissues, observed in the branch meristem and spikelet meristem regions, as well as in their vasculature and surrounding sheath (PubMed:17144896). Accumulates in incipient rudimentary- and empty-glume primordia (PubMed:22003982). Highly abundant in young developing panicles, but becomes later present at low levels in developing panicles and seeds. Found primarily in the boundary region of glume primordia (PubMed:17144896). Target of miR172 microRNA mediated cleavage, particularly during floral organ development. Delayed transition from spikelet meristems to floral meristems, resulting in the production of multiple rudimentary glumes in an alternative phyllotaxy. Abnormal development of additional bracts leading to altered floral architecture, inculding lemma/palea-like organs in place of empty glumes and lodicules, altered number of stamens and carpels, and ectopic florets occurring in the axil of the rachilla (PubMed:17144896, PubMed:22003982). The snb osids1 double mutant, lacking both SNB and IDS1, exhibits a decreased number of branches and spikelets within a panicle, as well as a strongly delayed transition to a floral meristem, associated with abnormal spatio-temporal expression of B- and E-function floral organ identity genes in the lodicules and of spikelet meristem genes (PubMed:22003982). Belongs to the AP2/ERF transcription factor family. AP2 subfamily. Extended N-terminus.