Effects of <i>Bacillus thuringiensis</i> 0271 on individual indicators of nonspecific resistance of <i>Origanum vulgare</i> L. to stressful conditions

Abstract

In this paper, we aim to study the effect of the Bacillus thuriengiensis strain var. darmstadiensis 0271 on the biochemical parameters of Origanum vulgare L., which determine its nonspecific resistance to unfavourable environmental conditions. The research materials were a liquid spore culture of B. Thuringiensis 0271 and the following oregano samples: 100.1 with 75.5% of carvacrol, g-4 with 52.0% of carvacrol, No. 2 with 59.85% of а -terpineol, No. 1 with 21.5% of germacrene D and 19.4% of в -caryophyllene. The preservation of the strain spores on the leaf surface of Origanum vulgare was determined using A.G. Kolchevskys method. The proline content was determined by V.A. Khramov’s and E.M. Ageeva’s method, while the pigment content was measured spectrophotometrically. The total content of phenolic compounds, ascorbic acid and water-soluble carbohydrates was established according to the methods by M.N. Zaprometov, M.M. Okuntsov and M. Dubois, respectively. Ten days after treating the leaves of the 100.1 and No. 1 oregano varieties with the spore culture of B. Thuringiensis 0271, the amount of chlorophylls decreased by 27.1 and 15.2% compared to the control, respectively. At the same time, the amount of chlorophylls increased by 91.4 and 72.7% in the leaves of the g-4 and No. 2 varieties, respectively. On the 10th day of the experiment, the amount of proline and phenolic compounds decreased by 4 times in the leaves of the g-4 sample. Compared to the control, the 100.1 variety demonstrated a decrease in the amount of soluble carbohydrates and phenolic compounds by 1.76 and 2.0 times, respectively. On the 10th day of the experiment, the treatment of O. vulgare plants with B. Thuringiensis 0271 promoted the accumulation of antioxidants in the leaves of the g-4 sample by 14.5% compared to the control.