The unconventional G-protein AtYchF1 interacts with the ribosomal protein AtRPS7 to modulate selective translation for balancing plant growth and stress response in Arabidopsis

Plants must balance normal growth with stress responses by interpreting environmental signals. This balancing act relies on key regulatory mechanisms, including post-transcriptional regulation, translational control, and protein degradation, which help maintaining appropriate cellular protein levels. Here, we investigated the role of the unconventional GTPase YchF1, a known negative regulator of stress responses, in resource allocation in Arabidopsis thaliana. Overexpressing AtYchF1 in the atychf1 mutant background improved growth under nutrient-deficient conditions but increased salt sensitivity, and these phenotypes were dependent on the interaction between AtYchF1 and the ribosomal protein AtRPS7. Proteomic and translatomic analyses revealed that AtYchF1 inhibited the translation of transcripts featuring a CUCU motif in their 3' untranslated regions, which is a predominant feature among stress-responsive genes, and this repression was AtRPS7 binding-dependent. By preventing the overproduction of stress-related proteins, AtYchF1 directs resources toward the production of translation- and photosynthesis-related proteins, especially under suboptimal nutrient conditions. Our findings established a novel physiological role for AtYchF1 in modulating stress protein production in the absence of abiotic/biotic stress, allowing plants to thrive, particularly in nutrient-deficient environments.