Oryza sativa LIGULELESS 2s determine lamina joint positioning and differentiation by inhibiting auxin signaling

Leaf angle affects architecture and grain yield, especially in cereal crops. The lamina joint (LJ) is a grass-specific organ that determines leaf angle; however, the mechanism that underlies LJ organogenesis in rice is unknown. Here, we identified two LIGULELESS 2 (LG2) genes in rice, OsLG2 and OsLG2L, and demonstrated that they were essential to determine LJ positioning; and the positioning determination-induced OsLG1 initiated the subsequent LJ tissue differentiation. Using OsLG2-cri OsLG2L-cri and OsLG1-cri lines for transcriptome analysis, we found that OsLG2/2L and OsLG1 initiated LJ through inhibiting auxin signaling. In addition, OsLG2/2L and OsLG1 function in a dose-dependent manner in LJ organogenesis and leaf angle formation. This study elucidates the mechanism of LJ organogenesis by LG genes in rice and provides a foundation for crop improvement.