Rice transcriptional repressor OsTIE1 controls anther dehiscence and male sterility by regulating JA biosynthesis
The coordination of pollen viability, stamen filament elongation and anther dehiscence is essential for the successful pollination and reproduction in angiosperms. The hormone jasmonic acid (JA) are crucial for these processes. However, the tight regulation of JA biosynthesis during stamen development is still largely unknown. Here, we demonstrate that the rice (Oryza sativa) ERF-associated amphiphilic repression (EAR) motif-containing protein TCP INTERACTOR CONTAINING EAR MOTIF PROTEIN1 (OsTIE1) tightly regulates JA biosynthesis by repressing TEOSINTE BRANCHED1/CYCLOIDEA/PROLIFERATINGCELLFACTORS (TCP) transcription factor OsTCP1/PCF5 during stamen development. The loss of OsTIE1 function in ostie1 mutants causes male sterility. The ostie1 mutants display inviable pollen, the early stamen filament elongation and the precocious anther dehiscence. JA biosynthesis is activated earlier and JA level is precociously increased in anthers of ostie1. The expression of OsTIE1 is developmentally regulated during stamen development. OsTIE1 is localized in nuclei and has transcriptional repression activity. We further show that OsTIE1 directly interacts with OsTCP1, and overexpression of OsTCP1 caused early anther dehiscence resembling that of ostie1. The expression of genes encoding key enzymes of JA biosynthesis including Oryza sativa lipoxygenase (OsLOX) genes is regulated by the OsTIE1-OsTCP1 complex. Our findings discover that the OsTIE1-OsTCP1 module plays critical roles in stamen development by finely tuning JA biosynthesis, and provides a new foundation to create male sterile plants for hybrid seed production. Overall design: To determine the molecular mechanisms that OsTIE1 affected the anther development, we collected anthers of stage 10 and stage 12 from ostie1-1 and WT control for RNA sequencing (RNA-Seq) analysis