Nuclear-SnRK1 localization improves salt stress tolerance responses

LANDO ANA PAULA; GIULIANO BARBIERI ; CLAUDIA NOME ; GISELLE MARTÍNEZ-NOËL ; RODRIGUEZ MARIANELA SOLEDAD

Rosario

Congreso; XXXIV Argentinian Meeting of Plant Physiology RAFV Conference 2023; 2023

Sociedad Argentina de Fisiología Vegetal

Salinization has long been known as a common environmental problem worldwide which directly affects photosynthesis and crop yield. Because of this, adaptation of metabolism and growth to adverse environmental conditions is essential to maintain cellular homeostasis and, therefore, organism survival. In this context, we studied the SnRK1 kinase which plays a central role to maintain energy and metabolism homeostasis, as a regulator of signaling networks for stress tolerance responses in plants. The aim of this work was to evaluate the impact of subcellular localization of SnRK1α-subunit (nuclear or cytosolic) in ultrastructure cell, chloroplast function, dry biomass in plants under salt stress. We evaluated cellular ultrastructure (TEM) and chlorophyll fluorescence (ChlF) in transgenic plants with forced SnRK1α-subunit localization (NLS- nuclear localization or MYR- cytosolic localization) and Wild-Type (Col-0) subjected to NaCl treatments. Results showed that NLS plants subjected to salt stress had cells with more organelles such as mitochondria and peroxisomes in relation to MYR-plants. NLS-mitochondria showed change in the morphology with shape cupped. MYR-chloroplasts presented structural distortion and possessed swollen thylakoids and poorly developed stroma. This phenotype was reflected in the ChlF analysis of MYR-plants, showing heat energy dissipation (NPQ, qL), changes in thylakoid electron transport with lower proton conductivity (LEF, gH+) in the principal components analysis. Interestingly, at the end of experiment, NLS-plants subjected to salt conditions maintained similar dry biomass to the ones without stress and showed Na/K decrease in relation to MYR-plants. Overall, the results reveal key roles for nuclear SnRK1 in response to tolerance to NaCl stress.