Oxidative homeostasis of germinating wheat seeds depending on the ultrasonic effect’s duration

Abstract

Background. Ultrasound is actively used to influence living organisms, but its physiological effect remains not fully understoodIn connection with the ability of ultrasonic waves to generate reactive oxygen species in an aqueous medium, special attention, from our point of view, should be paid to oxidative homeostasis and primary proteolysis of a reserve nutrient in germinating seeds. As the main indicators, attention should be paid to the proteins’ oxidative modification (POM), since they are the main traps of bioradicals, but their turnover in plant tissues remains unexplored. The purpose of the research is to study the effect of different times of ultrasonic exposure on the level of POM, lipid peroxidation (LPO), cysteine proteinase activity and expression of its gene (CP) in germinating wheat seeds. Materials and methods. Wheat seeds (Triticum aestivum L.), “Ekada-70” variety, collected in 2018, were used as the object of the study. The seeds were placed in an aqueous medium of an ultrasonic bath “UNITRA – UNIMA” UM – 4. The treatment was carried out for 5, 10, and 20 minutes; seeds soaked but not sonicated served as a control. At the end, the level of lipid peroxidation was determined in the seeds by the level of malonic dialdehyde (MDA) concentration, OMB registration of 2,4 – denitrophenylhydrazones (2,4 – DNPH), cysteine proteinase activity and gene expression (CP). Results. The experiments revealed the dependence of the studied parameters on the time of ultrasonic exposure. An increase in MDA content in germinating wheat seeds was shown after ultrasonic exposure. The content of 2,4 – DNPH had a wave-like dynamics, did not statistically significantly change in germinating seeds exposed to ultrasound for 5 min, increased in samples that were exposed to ultrasound for 10 min, and decreased in seeds treated with ultrasound for 20 minutes. The activity of the studied proteinase was higher in the samples after 5 minutes of ultrasonic treatment and lower than the control values in the seeds after 20 minutes of sonication. Gene expression (SR) was higher in germinating seeds subjected to 5–10 minutes ultrasonic treatment, followed by a fall below the control. Conclusions. The intensification of LPO processes, the wave-like dynamics of POM and the primary activation of proteolysis with subsequent inhibition in germinating wheat seeds after ultrasound exposure were established; protein homeostasis is more tolerant to the action of ROS compared to lipids.

Keywords

• oxidative modification of proteins
• lipid peroxidation
• cysteine proteinases
• seeds of wheat
• seed germination
• ultrasound