PhSLB1 Regulates Branch Development in Petunia

Abstract

F-box proteins play crucial roles in various developmental stages in plants, such as shoot branching. As an important ornamental and model plant, the branch development of petunia has always been a hot research topic. In our study, the homologous gene of SMALL LEAF AND BUSHY1 (SLB1) was isolated from Petunia ×hybrida cv. Mitchell Diploid. PhSLB1 contained a C-terminal WD40 repeat domain and an N-terminal F-box domain. An analysis of expression indicated that PhSLB exhibited the highest expression in roots, whereas expression levels were lowest in stems and leaves. Subcellular localization assays demonstrated that PhSLB1 was localized on the nucleus. Furthermore, RNA interference (RNAi) of PhSLB1 in petunia significantly increased the branch number. Quantitative real-time polymerase chain reaction showed that PhSLB1 not only regulated cytokinin and strigolactone pathway but also affected the expression of some key branching-related genes, such as PhBRC1, PhKNOX, PhH2A, and PhL27. Our research establishes a theoretical groundwork for revealing the mechanism by which SLB1 regulates branch development.

Keywords

• petunia
• shoot branching
• slb1
• subcellular localization
• rnai