Bes1 brassinosteroid

  • Brassinosteroids (BRs) are essential plant hormones regulating various developmental processes.
  • BRs show structures similar to animal steroidal hormones.
  • Brassinolide is the final product of the BR biosynthetic pathway and the most active BR.
  • BRs are perceived by transmembrane receptor complexes including the receptor BRI1 and co‐receptor BAK1.
  • BRs cannot be transported in a long distant manner.
  • BES1 and BZR1 are the critical downstream transcription factors regulating the expression of thousands of BR response genes.

Brassinosteroids (BRs) are important regulators for plant growth and development. BRs signal to control the activities of the BES1 and BZR1 family transcription factors. The transcriptional network through which BES1 and BZR regulate large number of target genes is mostly unknown. By combining chromatin immunoprecipitation coupled with Arabidopsis tiling arrays (ChIP-chip) and gene expression studies, we have identified 1609 putative BES1 target genes, 404 of which are regulated by BRs and/or in gain-of-function bes1-D mutant. BES1 targets contribute to BR responses and interactions with other hormonal or light signaling pathways. Computational modeling of gene expression data using Algorithm for the Reconstruction of Accurate Cellular Networks (ARACNe) reveals that BES1-targeted transcriptional factors form a gene regulatory network (GRN). Mutants of many genes in the network displayed defects in BR responses. Moreover, we found that BES1 functions to inhibit chloroplast development by repressing the expression of GLK1 and GLK2 transcription factors, confirming a hypothesis generated from the GRN. Our results thus provide a global view of BR regulated gene expression and a GRN that guides future studies in understanding BR-regulated plant growth.

Bes1 brassinosteroid

bes1 brassinosteroid

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