MYB83 plays an important negative role in ethylene-mediated root hair growth and involves in plant tolerance three...

Root hairs are important for plant growth, development, and tolerance of environmental stresses such as nutrient deficiencies. Ethylene (ET) is required for root hair growth in response to nutrient deficiencies. However, the related molecular mechanisms are largely unknown. Here, MYB83, a MYB transcription factor, was highly expressed in root hairs. Two independent myb83 mutant alleles displayed increased root hair growth, and overexpression of MYB83 led to the inhibition of root hair growth in Arabidopsis. Further, ethylene signaling reduces MYB83 transcript accumulation and protein levels in root hairs. ET pharmacology experiments illustrated that the loss of MYB83 led to the insensitivity of root hair growth in response to ET signaling, suggesting that MYB83 plays an important negative role in ET-mediated root hair growth. It has been proved that ETHYLENE INSENSITIVE3 (EIN3) is crucial in ET-mediated root hair growth. Our results showed that MYB83 directly bound to the promoter of EIN3 and inhibited its expression in root hairs and its role in root hair growth. Further, the inhibition of the MYB83-EIN3 module was key for root hair growth, nutrient absorption, and plant tolerance to three nutrient deficiencies, including nitrogen (N), phosphorus (P), or potassium (K⁺) deficiencies. In summary, this study demonstrated that MYB83 plays an important negative role in ET-mediated root hair growth by directly regulating EIN3, and the MYB83-EIN3 module is involved in plant tolerance three major nutrient stresses.