Unveiling the SnRK1.1-mediated response in plants to non-optimal growth conditions

CALDO, A; FUSARI CM; CANTOIA, A; ROSANO, G; LIEBSCH, D; DENGJEL, J; BLANCO, NICOLAS E

Workshop; EMBO Workshop: Target of rapamycin (TOR) signaling in photosynthetic organisms; 2021

EMBO

In photosynthetic organisms, mounting evidence has confirmed the tight connection between TOR and SnRK1 -mediated signalling pathways to adjust cellular metabolism to energy status (1, 2). This crosstalk represents one of the central adaptive mechanisms deployed by plants to face highly variable external conditions, which affect photosynthetic yield and consequently energy status. In this scenario, the intracellular behaviour of SnRK1.1 is a fundamental aspect of the mechanism of restoring energy homeostasis (3, 4). Chloroplasts are one of the central intracellular hotspots where changes in growth conditions provoke energy imbalance in photosynthetic cells (5). To reveal how SnRK1 buffers this energy perturbations, we challenged photosynthetic yield and survey for SnRK1 interactors using a SnRK1.1 pull-down strategy in leaf extracts followed by MS protein identification. Our treatment mimics the induction of the “photosynthetic control” mechanism when external conditions decrease photosynthetic performance. In addition to well-known SnRK1.1 targets (e.g., nitrate reductase), we found a previously unreported set of potential SnRK1.1 interactors including components of the energy metabolism and metabolite transporters. The relevance of these results, their physiological and intracellular significance in the context of SnRK1-TOR cross-regulation and implications in the plant response to changing environmental conditions will be discussed in the presentation.