SALTS · Selective autophagy links in plant response to stress

Increase in soil salinity is a major agricultural threat worldwide, therefor investigating plant molecular mechanisms for mitigation of salt-induced stress is necessary and timely. Salt stress triggers extensive proteome remodelling to maintain cellular proteostasis, a process relying on selective proteolytic pathways such as autophagy, which recycles cellular components via double-membraned vesicles. Although autophagy is known to be crucial for plant salt-stress responses, the molecular mechanisms underlying its selective activation remain elusive. The proposed project, SALTS, aims to close this gap by elucidating the principles of selective autophagy initiation during salt stress. Central to this effort is the poorly characterized plant protein ATG11. Conserved in other model systems, ATG11 is essential for initiation of autophagosome formation and recruitment of selective autophagy receptors (SAR). This makes ATG11 a prime candidate to uncover how selective autophagy is orchestrated in plants. SALTS will pursue three objectives: (i) define how Arabidopsis thaliana ATG11 engages with autophagy components, unravelling the molecular binding modes thanks to gold-standard methods supported by the host labs; (ii) characterize the subcellular regulation of AtATG11 during salt stress and its role in SAR recruitment using advanced live-cell imaging facility from the host institute; and (iii) exploit ATG11’s central function to develop a novel proximity-labelling tool enabling unprecedented resolution of the selective autophagy proteome under stress. SALTS will close fundamental gaps in our understanding of plant autophagy, clarifying its contribution to stress resilience and creating an innovative approach to investigate this process. Altogether, SALTS will deliver essential insights into plant stress biology with impacts extending beyond plant science while being a springboard for my development as an independent researcher.