Interplay between TOR and SnRk1 in the accumulation of Proline under salt stress

LANDO A; BARBIERI G; MARTÍNEZ NOËL G; RODRIGUEZ M

Congreso; SAIB 2023; 2024

Plants are subjected to a diverse array of abiotic stressors and respond with metabolic changes that negatively impact their growth and development. Thus, the kinases TOR and SnRK1 form the core of a complex and intricate regulatory network to coordinate metabolic activities. However, the interplay of TOR and SnRK1 signaling on the accumulation of stress-regulated metabolites is poorly understood. Thus, we studied proline (Pro) which is a multifunctional amino acid that also functions as a protector compound and participates in cell redox regulation. Besides, Pro acts as a metabolic signal to many cellular responses under various stress conditions. The aim of this work was to evaluate the role between TOR and SnRk1 in the accumulation of Pro in Arabidopsis plants with different subcellular localization of SnRK1α-subunit (nuclear or cytosolic) under salt stress. We evaluated Pro accumulation in transgenic plants with forced SnRK1α-subunit localization (NLS- nuclear localization or MYR- cytosolic localization) and Wild-Type (Col-0) subjected to inhibition of TOR activity (AZD) under NaCl treatment. We also analyzed the expression of genes that encode key enzymes of Pro metabolism (P5CS and ProDH). Results showed that under salt stress conditions with TOR inhibition, the cellular localization of SnRK1 influenced Pro accumulation. MYR-plants accumulated significantly less Pro relative to Col-0 and NLS plants. This was reflected in the levels of transcripts related to Pro catabolism which significantly increased in MYR-plants. Overall, our results suggest that TOR would be negatively regulating ProDH1 transcription under salt stress conditions, especially when SnRK1 is found in cytosol.