NITRATE TRANSPORTER1/PEPTIDE TRANSPORTER FAMILY4 interacts with DENSE AND ERECT PANICLE1 and regulates grain number in rice

The grain number per panicle is a key agronomic trait of ideal plant architecture in rice (Oryza sativa L.). Here, we characterized and cloned OsNPF4, a member of the NITRATE TRANSPORTER 1/PEPTIDE TRANSPORTER (NPF) family that substantially alters rice yield. Overexpression of OsNPF4 significantly increased grain number per panicle but decreased panicle number. OsNPF4 was activated by IDEAL PLANT ARCHITECTURE1 (IPA1) via the SQUAMOSA promoter binding protein-like (SPL) binding sites in its promoter. Additionally, OsNPF4 interacted with DENSE AND ERECT PANICLE1 (DEP1), whose transcription is also induced by IPA1. Our findings indicate that OsNPF4 contributes to establishing ideal plant architecture in rice, and manipulating its expression could help produce elite super rice varieties.