Abstract
INTRODUCTION: Crown root is an important part of rice root system, and the development of crown root is regulated by a series of plant-specific transcription factors. As a significant plant-specific transcription factor family, the relationship between IDD and rice crown root development remains elusive. METHODS: Here the function of OsIDD9 in rice crown root development was identified by genetic, biochemical, and molecular evidence. RESULTS: OsIDD9 over-expression lines exhibited a defective crown root phenotype, while OsIDD9 knockout lines displayed vigorous crown roots, indicating that OsIDD9 is a negative regulator of crown root development. Further studies have shown that OsIDD9 affects crown root development by regulating the expression of downstream key genes such as OsWOX11, OsCRL5. In addition, the expression of OsIDD9 is regulated by the upstream open reading frame (uORF) at translation level. DISCUSSION: This study reveals the role of the OsIDD9-mediated genetic pathway in the development of rice crown roots, and provides theoretical support for clarifying the interactions among different transcription factors in rice crown root development.