Nuclear auxin signalling induces autophagy for developmental reprogramming
The phytohormone auxin is a central regulator of plant growth and development, traditionally known for mediating transcriptional reprogramming through the canonical TIR1/AFB-Aux/IAA signalling pathway. In this study, we reveal that auxin rapidly induces macroautophagy, a catabolic process critical for the removal and recycling of superfluous macromolecules. We demonstrate that natural auxin (IAA) triggers autophagy at physiological concentrations. Genetic and pharmacological analyses show that TIR1/AFB receptors and their adenylate cyclase activity are indispensable for autophagy induction. Furthermore, auxin-induced autophagy depends on transcription, highlighting its integration with the broader gene regulatory networks. Functionally, we show that auxin-induced autophagy is required for efficient developmental reprogramming and organogenesis in both root and shoots. Autophagy is induced at places of local auxin maxima and autophagy-deficient mutants exhibit delayed differentiation and retarded organ primordia progression at the meristematic zones. Together, our findings uncover a dual role for auxin in coordinating gene expression and autophagic clearance, thereby facilitating rapid and effective developmental transitions.