• hypoxic stress
• submergence
• fermentative mutants
• Arabidopsis thaliana

Hypoxia is a condition characterized by a deficiency of O2 concentration in cells and tissues. Many causes can trigger this phenomenon, including – in plants – naturally occurring flooding events. This can negatively affect oxygen levels throughout the organism.
For this reason plants, which are sessile, have evolved responses to abiotic stresses. They can be perceived, and as a result, complex responses are elicited at different levels. Metabolic reactions are also affected by this condition, particularly energy pathways. More specifically, limited O2 availability for respiration results in a shift to metabolic fermentation, where pyruvate obtained from glycolysis can be converted into different metabolites in order to sustain energy metabolism and replete NAD+ supplies for glycolysis.
In this study, for the first time, we generated multiple mutant lines for different combinations of pyruvate-consuming pathways. We also assessed the impact of abolishing the enzymatic activity on Arabidopsis thaliana performance during hypoxic stresses. To this end, we used newly-obtained ldh1/adh1, ldh/pdc1,2 and alaat1/alaat2 A. thaliana mutants. We evaluated them in terms of gene expression, transient expression of luciferase reporter gene and tolerance to submergence.
The results point to the need for further research in order to acquire a better understanding of the contribution of distinct pyruvate converting pathways in Arabidopsis.