Multifaceted Roles of SPL9 in Plant Growth, Development, and Stress Responses: A Review

The SQUAMOSA PROMOTER BINDING PROTEIN-LIKE (SPL) family, a group of plant-specific transcription factors, plays a key role in plant growth and development through complex regulatory networks. Within this family, SPL9 has been identified as a key regulator of diverse biological processes. In this review, we summarize the current knowledge on SPL9, focusing on its expression regulatory mechanisms and roles in plant development, such as morphogenesis, reproductive processes, and crop yield determinations. We further describe its role in plant responses to abiotic and biotic stresses and its integration into broader regulatory networks. We also outline future research priorities and discuss potential applications of SPL9-based strategies in molecular design breeding to increase crop productivity and stress resistance.