1. EIN3 and RSL4 interfere with an MYB-bHLH-WD40 complex to mediate ethylene-induced ectopic root hair formation in Arabidopsis .
- Author
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Qiu Y, Tao R, Feng Y, Xiao Z, Zhang D, Peng Y, Wen X, Wang Y, and Guo H
- Subjects
- Arabidopsis genetics, Arabidopsis metabolism, Arabidopsis Proteins genetics, Basic Helix-Loop-Helix Transcription Factors genetics, Cell Differentiation genetics, Gene Expression Regulation, Plant, Homeodomain Proteins genetics, Homeodomain Proteins metabolism, Multiprotein Complexes, Plant Epidermis cytology, Plant Epidermis genetics, Plant Epidermis growth & development, Plant Epidermis metabolism, Plant Roots genetics, Plant Roots growth & development, Plant Roots metabolism, Protein Binding, Signal Transduction, Arabidopsis growth & development, Arabidopsis Proteins metabolism, Basic Helix-Loop-Helix Transcription Factors metabolism, DNA-Binding Proteins metabolism, Ethylenes metabolism, Transcription Factors metabolism
- Abstract
The alternating cell specifications of root epidermis to form hair cells or nonhair cells in Arabidopsis are determined by the expression level of GL2 , which is activated by an MYB-bHLH-WD40 (WER-GL3-TTG1) transcriptional complex. The phytohormone ethylene (ET) has a unique effect of inducing N-position epidermal cells to form root hairs. However, the molecular mechanisms underlying ET-induced ectopic root hair development remain enigmatic. Here, we show that ET promotes ectopic root hair formation through down-regulation of GL2 expression. ET-activated transcription factors EIN3 and its homolog EIL1 mediate this regulation. Molecular and biochemical analyses further revealed that EIN3 physically interacts with TTG1 and interferes with the interaction between TTG1 and GL3, resulting in reduced activation of GL2 by the WER-GL3-TTG1 complex. Furthermore, we found through genetic analysis that the master regulator of root hair elongation, RSL4, which is directly activated by EIN3, also participates in ET-induced ectopic root hair development. RSL4 negatively regulates the expression of GL2 , likely through a mechanism similar to that of EIN3. Therefore, our work reveals that EIN3 may inhibit gene expression by affecting the formation of transcription-activating protein complexes and suggests an unexpected mutual inhibition between the hair elongation factor, RSL4, and the hair specification factor, GL2. Overall, this study provides a molecular framework for the integration of ET signaling and intrinsic root hair development pathway in modulating root epidermal cell specification., Competing Interests: The authors declare no competing interest.
- Published
- 2021
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