Tomato SlARF5 participate in the flower organ initiation process and control plant height.

Plant height is a critical agronomic trait closely linked to yield, primarily regulated by Gibberellins (GA) and auxins, which interact in complex ways. However, the mechanism underlying their interactions remain incompletely understood. In this study, we identified a tomato mutant exhibiting significantly reduced plant height. Through gene cloning and bulked segregant analysis (BSA) sequencing, we found that the mutant gene corresponds to the tomato auxin response factor gene SlARF5/MP. Here, we show that overexpression of SlARF5/MP significantly enhances plant height. Additionally, treatment with GA₃ restored the plant height of the mutant to wild-type (WT) levels, indicating that GA content is a key factor influencing plant height. We also observed significant upregulation of GA-biosynthesis genes, including GA2-oxidases GA20ox3 and GA20ox4, as well as the GA₃ biosynthesis gene GA3ox1, in SlARF5-overexpressing plants. Furthermore, we demonstrated that SlARF5 directly binds to SlGA2ox3, which mediates the conversion of GA₃ to inactive GA, therebyregulating its expression. Our findings suggest that SlARF5 modulates GA₃ metabolism by regulating GA synthesis genes, ultimately leading to alterations in plant height.