Comprehensive analysis of downstream transcriptomic features in the competitive relationships between BEH3 and other BES/BZR transcription factors

Members of a plant-specific BES/BZR transcription factor (TF) family including regulate various developmental processes and environmental responses. Recently, we reported that BES1/BZR1 Homolog 3 (BEH3) exhibited a competitive effect toward other BES/BZR TFs. In this study, we analyzed transcriptome profiles in BEH3-overexpressing plants and compared them with those of BES1 and BZR1 double gain-of-function mutants. We identified 46 differentially expressed genes (DEGs), which were downregulated in the gain-of-function mutants of BES1 and BZR1 but upregulated upon BEH3 overexpression. In these DEGs, putative BES1 and BZR1 direct-targeted genes were highly enriched. In addition, these DEGs contained not only known brassinosteroid biosynthetic enzymes, but also some NAC TFs, which negatively regulate brassinosteroid-inactivating enzymes. Moreover, the iron sensor and the iron-deficient response-related bHLH TFs were also included. Taken together, our findings indicate that a competitive relationship between BEH3 and other BES/BZR TFs exists in various BES/BZR binding target genes.

Automated summary

Members of the plant-specific BES/BZR transcription factor family play roles in regulating various developmental processes and environmental responses. In this study, we found that BEH3 has a competitive effect on other BES/BZR TFs. Transcriptome analysis identified 46 differentially expressed genes (DEGs), which were downregulated in BES1 and BZR1 gain-of-function mutants but upregulated in BEH3-overexpressing plants. These DEGs not only contained known brassinosteroid biosynthetic enzymes but also NAC TFs and iron-related bHLH TFs. Our findings reveal a competitive relationship between BEH3 and other BES/BZR TFs in the regulation of target genes.