Russian Federation
Russian Federation
Russian Federation
The GABA shunt is an anaplerotic pathway of the tricarboxylic acid cycle (TCA) that plays a critical role in plant adaptation to abiotic stresses, including hypoxia. It comprises several key enzymes: glutamate decarboxylase (GAD, EC 4.1.1.15), GABA transaminase (GABA-T, EC 2.6.1.19), and succinic semialdehyde dehydrogenase (SSADH, EC 1.2.1.24). Glutamate dehydrogenase (GDH, EC 1.4.1.2) facilitates the coupling between the GABA shunt and the TCA cycle. The GABA shunt bypasses two reactions of the TCA cycle due to reduced activity of the 2-oxoglutarate dehydrogenase complex (EC 1.2.1.105), providing an alternative route for carbon utilization and maintaining cellular energy balance under oxygen-deficient conditions. Under hypoxia, activation of the GABA shunt promotes the stabilization of the redox state and supports oxidative phosphorylation. We investigated the effect of hypoxia on the activity and gene expression of GABA shunt enzymes (glutamate dehydrogenase, glutamate decarboxylase, GABA transaminase, and succinic semialdehyde dehydrogenase) in maize leaves. Our results demonstrate that hypoxia induces alterations in the activity and gene expression of GABA shunt enzymes, and also influences the methylation patterns of glutamate dehydrogenase genes. It was elucidated that plant cells adapt to oxygen deficiency at the transcriptional and epigenetic levels.
glutamate dehydrogenase, glutamate decarboxylase, GABA transaminase, succinic semialdehyde dehydrogenase, GABA shunt, hypoxia, expression, methylation
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