The unconventional G protein AtYchF1 interacts with ribosomal protein AtRPS7 to modulate selective translation for balancing plant growth and stress responses 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 maintain appropriate cellular protein levels. Here, we investigate the role of the unconventional GTPase YchF1, a known negative regulator of stress responses, in resource allocation in Arabidopsis thaliana. Overexpression of AtYchF1 in the atychf1 mutant background improves growth under nutrient-deficient conditions but increases salt sensitivity, and these phenotypes depend on the interaction between AtYchF1 and the ribosomal protein AtRPS7. Proteomic and translatomic analyses revealed that AtYchF1 inhibits the translation of transcripts containing a CUCU motif in their 3' untranslated regions, a feature prevalent among stress-responsive genes, and that this repression is AtRPS7-binding dependent. By preventing the overproduction of stress-related proteins, AtYchF1 redirects resources toward the production of translation- and photosynthesis-related proteins, particularly under suboptimal nutrient conditions. Our findings establish a novel physiological role for AtYchF1 in restraining stress protein production in the absence of abiotic or biotic stress, thereby enabling plants to thrive, especially in nutrient-deficient environments.