Root hair lifespan is antagonistically controlled by autophagy and programmed cell death

Root hairs are tubular tip-growing extensions of root epidermal cells that enhance root surface area for water and nutrient acquisition. While the mechanisms governing root hair fate, polarity and tip growth are well understood, the regulation of root hair longevity remains largely unknown. Here we show that root hair cells employ high levels of autophagy to maximize their lifespan in Arabidopsis thaliana. Loss-of-function mutations in the genes encoding the autophagy regulators ATG2, ATG5 or ATG7 induce a premature, cell-autonomous cell death program. This cell death is activated via a gene regulatory network promoted by the NAC transcription factors ANAC046 and ANAC087. Our findings uncover an antagonistic relationship between autophagy and senescence-controlled programmed cell death in root hair lifespan regulation, with potential implications for optimizing plant nutrient and water uptake in crop breeding.