Fig. 8
A current model showing that BES1 family members (or BES1 transcription factors, BES1 TFs) are essential downstream regulatory components in the TPD1-EMS1/SERKs pathway. In previous studies it was thought that BES1 family members play fundamental roles in regulating BR signaling pathway. A previous report proposed that EMS1 regulates tapetum development through interaction and activation of a group of beta carbonic anhydrases (β-CAs). In this study we suggest that BES1 family members can be activated by EMS1-mediated signaling to regulate tapetum formation. Our ChIP analyses suggest that BES1 and BZR1 can directly bind to the promoter regions of a number of tapetum developmental genes, such as SPL, DYT1, and TDF1. In addition, phenotypic similarity between the sextuple mutant and spl implies that BES1 family members may control SPL expression in earlier anther development. The detailed mechanism remains to be elucidated
