A proposed role for selective autophagy in regulating auxin-dependentlateral root development under phosphate starvation in Arabidopsis

摘要

Plants respond to limited soil nutrientavailability by inducing more lateralroots (LR) to increase the root surfacearea. At the cellular level, nutrient starva-tion triggers the process of autophagythrough which bulk degradation of cellu-lar materialsis achieved to facilitatenutrient mobilization. Whether there isany link between the cellular autophagyand induction of LR had remainedunknown. We recently showed that theS-Domain receptor Kinase (ARK2) andU Box/Armadillo Repeat-Containing E3ligase(PUB9) module is required for lat-eral root formation under phosphate star-vation inArabidopsis thaliana.1We alsoshowed that PUB9 localized to autopha-gic bodies following either activation byARK2 or under phosphate starvation andark2–1/pub9–1 plantsdisplayed lateralroot defects with inability to accumulateauxin in the root tips under phosphatestarvation.1Supplementing exogenousauxin was sufficient to rescue the LRdefects inark2–1/pub9–1 mutant. Block-ing of autophagic responses in wild-typeArabidopsis also resulted in inhibition ofboth lateral roots and auxin accumula-tion in the root tips indicating the impor-tance of autophagy in mediating auxinaccumulation under phosphate starvedconditions.1Here, we propose a modelfor ARK2/AtPUB9 module in regulationof lateral root development via selectiveautophagy.