College of Life Sciences, Ritsumeikan University.
Graduate School of Science, Kobe University.
Genes Genet Syst. 2023 Sep 5;98(2):89-92. doi: 10.1266/ggs.23-00029. Epub 2023 Jun 16.
Members of a plant-specific BES/BZR transcription factor (TF) family including BRI1-EMS-SUPPRESSOR 1 (BES1) and BRASSINAZOLE-RESISTANT 1 (BZR1) 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.
植物特异性 BES/BZR 转录因子（TF）家族成员，包括 BRI1-EMS-SUPPRESSOR 1（BES1）和 BRASSINAZOLE-RESISTANT 1（BZR1），调节各种发育过程和环境响应。最近，我们报道了 BES1/BZR1 Homolog 3（BEH3）表现出对其他 BES/BZR TF 的竞争效应。在本研究中，我们分析了 BEH3 过表达植物的转录组谱，并将其与 BES1 和 BZR1 双功能获得突变体进行了比较。我们鉴定了 46 个差异表达基因（DEGs），这些基因在 BES1 和 BZR1 的功能获得突变体中下调，但在 BEH3 过表达时上调。在这些 DEGs 中，推测的 BES1 和 BZR1 直接靶向基因高度富集。此外，这些 DEGs 不仅包含已知的油菜素内酯生物合成酶，还包含一些 NAC TF，它们负调控油菜素内酯失活酶。此外，还包括铁传感器和缺铁响应相关的 bHLH TF。综上所述，我们的研究结果表明，BEH3 和其他 BES/BZR TF 之间存在竞争关系，存在于各种 BES/BZR 结合靶基因中。
