EIN3 and RSL4 interfere with an MYB–bHLH–WD40 complex to mediate ethylene-induced ectopic root hair formation in Arabidopsis

Significance Plant hormones widely regulate reprogramming of stereotypic cell specifications for plants to prevail in ever-changing environments. The well-known observation that ethylene (ET) specifically promotes root hair formation from the N-position epidermal cells provides an excellent model to dissect how such reprograming events are regulated at the molecular level. This work uncovers a molecular mechanism that wires the ET signaling with the root hair specification cascade. Unexpectedly, we found that a well-recognized master regulator of root hair elongation also participates in ET-regulated root epidermal cell specification, implying the internal robustness of root epidermal cell specification.