Exogenous alpha lipoic acid can stimulate photosystem II activity and the gene expressions of carbon fixation and chlorophyll metabolism enzymes in maize seedlings under drought
Citation
Sezgin, A., Altuntaş, C., Demiralay, M., Cinemre, S., & Terzi, R. (2019). Exogenous alpha lipoic acid can stimulate photosystem II activity and the gene expressions of carbon fixation and chlorophyll metabolism enzymes in maize seedlings under drought. Journal of plant physiology, 232, 65-73.Abstract
Protective compounds such as non-enzymatic antioxidants, osmolytes and signal molecules have been applied to
plants exposed to various environmental stresses to increase their stress tolerance. However, there are not enough records about the response of plants to alpha lipoic acid (ALA) application with antioxidant properties.
Therefore, this study was designed to evaluate the function of exogenous ALA on the photosynthetic performance of maize seedlings grown in hydroponic conditions under drought stress. Three weeks old seedlings were
treated with or without ALA (12 μM) and they were subjected to drought stress induced by 10% polyethylene
glycol (PEG6000) for 24 h. Chlorophyll content, gas exchange parameters, chlorophyll fluorescence and the expression levels of genes involved in CO2 fixation (ribulose-1,5-bisphosphate carboxylase (rubisco), phosphoenolpyruvate carboxylase (PEPc), Rubisco activase (RCA)) and chlorophyll metabolism (magnesium chelatase (MgCHLI) and chlorophyllase (Chlase)) were determined. The application of ALA increased chlorophyll content and
the activity of photosystem II in comparison to the untreated seedlings under drought stress. The relative expression levels of Rubisco, PEPc, RCA and Mg-CHLI significantly increased while the Chlase gene expression
decreased in seedlings to which ALA was applied in comparison those to which it was not applied under the
stress. These results suggest that exogenous ALA can enhance the photosynthetic performance of maize seedlings
exposed to drought by inducing photosystem II activity and the gene expressions of carbon fixation and
chlorophyll metabolism enzymes.