PhNAL1 Is Involved in Regulating Branch Development of Petunia

The branch number of plants is an important agronomic trait that directly influences the ornamental characters and production costs of ornamental plants. Shoot branching has always been a hot topic for Petunia hybrida. During our research, we isolated the homologous gene of narrow-leaf 1 (NAL1), denoted as PhNAL1. The expression level of PhNAL1 was higher in leaves and axils than in roots, stems, and flowers. Pertinent to shoot apex removal and 6-benzyladenine treatments, both interventions demonstrated a suppressive effect on the expression of PhNAL1. Through subcellular localization analysis, we found that PhNAL1 predominantly localized in the nucleus. By using RNA interference targeting PhNAL1, we induced a noticeable increase in branch number while concurrently reducing plant height of petunia. These findings demonstrate that PhNAL1 is involved in regulating branch development within petunia. This study provides genetic resources for the subsequent cultivation of new cultivars of petunia endowed with distinct branching characteristics.