Analysis of Molecular Mechanisms of Chronic Irradiation Effects on Electrical Signals in Wheat Plants

The effect of ionizing radiation (IR) on plants is mainly realized by altering the status of signaling systems and modifying stress signals. Variation potential (VP) is one of the types of electrical signals in plants. IR contributes to an increase in the amplitude of the VP, but the mechanisms of such influence are practically unknown. A possible way to implement changes arising from the action of IR is the regulation of gene expression. In the present work, the changes in the gene expression of participants in the generation and propagation of VP in irradiated plants are investigated. The experiments were performed on 14–15-day-old wheat plants (Triticum aestivum L.) grown under chronic irradiation (source ⁹⁰Sr–⁹⁰Y) with a dose rate of 31.3 μGy/h. The maximum accumulated dose was about 11.3 mGy. The irradiated plants showed no changes in the expression of calcium (TPC1), anionic (ALMT1 and CLC1), potassium (AKT1) channels, H⁺-ATPase (HA1), and NADPH oxidase (RBOHs) genes. A decrease in the expression of the SKOR potassium channel gene was revealed. The potassium channel blocker, tetraethylammonium chloride, caused an increase in response amplitude in control plants comparable to the increase in amplitude in the irradiated group. The obtained results indicate that one of the ways IR influences the electrical signals of plants is to inhibit the expression of the potassium channel.