Transcriptome Profiling of the Potato Exposed to French Marigold Essential Oil with a Special Emphasis on Leaf Starch Metabolism and Defense against Colorado Potato Beetle

Glutathione Involvement in Potato Response to French Marigold Volatile Organic Compounds

To elucidate the involvement of glutathione in the mitigation of induced oxidative changes and the sequestration of perceived volatiles in cells, we exposed potato plants to French marigold essential oil. The formation of short-lived radicals, the determination of scavenging activity towards ascorbyl and DPPH radicals, and the assessment of the potato plants' overall intra/extracellular reduction status were performed using electron paramagnetic resonance spectroscopy (EPR). The results showed the presence of hydroxyl radicals in potatoes, with significantly reduced accumulation in exposed plants compared to the control group after 8 h. However, the kinetics of EPR signal intensity change for the pyrrolidine spin probe (3CP) in these plants showed very low reducing potential, suggesting that the antioxidant system acts lethargically and/or the probe has been reoxidized. Total glutathione and its reduced/oxidized form ratio, determined spectrophotometrically, showed that the exposed plants initially had lower glutathione levels with diminutive, reduced form compared to the control. Still, after 8 h, both characteristics were similar to those of the control. RT-qPCR analysis revealed that the volatiles altered the expression of glutathione metabolism-involved genes, especially that of glutathione-S-transferase, after 8 h. Glutathione metabolism was affected by volatiles in the initial response of potato plants exposed to French marigold essential oil, and glutathione molecules were involved in the mitigation of induced oxidative burst.