ENERGY AND GROWTH: CROSS-TALK BETWEEN CYTOCHROME C AND THE SNRK1-DEPENDENT GROWTH AND STRESS REGULATORY PATHWAY

CORONEL, MARÍA FLORENCIA; GRASS, DIANA; CANAL, M VICTORIA; WELCHEN, ELINA; GONZALEZ, DANIEL H

Congreso; LVIII Annual Meeting of the Argentine Society for Biochemistry and Molecular Biology Research; 2022

In eukaryotic organisms, respiration takes place in mitochondria and involves the transport of electrons through a series of protein complexes that oxidize reduced coenzymes and reduce oxygen. Cytochrome c (CYTc) is a small heme protein that participates in electron transport coupled with ATP synthesis. Mutants in CYTc-1, one of the Arabidopsis CYTc-encoding genes, have shorter roots, smaller rosettes and delayed growth. Under the hypothesis that an alteration in CYTc levels modifies the activity of growth regulatory pathways related with energy availability, we studied a possible connection between CYTc and the SNF1 (sucrose non-fermenting 1)-related protein kinases 1 (SnRK1) pathway, involved in adjusting cellular metabolism during starvation and stress conditions. Transcriptomic analysis of CYTc mutants showed that CYTc and SnRK1 affect the expression of a common set of genes. Then, we analyzed whether the decrease or overexpression of CYTc alters the SnRK1 pathway. We determined that changes in CYTc levels affect the phosphorylation state of SnRK1, which is related to its activation. In agreement, transcript levels of starvation marker genes regulated by SnRK1 were affected in cytc mutants. To further explore the connection between CYTc and the SnRK1 pathway, we made genetic crosses between CYTc and SnRK1 overexpressing and mutant lines. Our results suggest that CYTc levels affect the activity of the SnRK1 pathway, probably through changes in mitochondrial energy production, to adjust cellular metabolism and growth to changes in respiration.