Quantitative profile of phenolic acids and antioxidant activity of wheat grain exposed to stress

Abstract

In the case of biotic and abiotic stresses, natural defence mechanisms are triggered in plants. The mechanisms are based mainly on enzymatic or non-enzymatic intracellular reactions. Changes in the quantitative profile of 12 phenolic acids, total bound phenolic acids, total free phenolic acids and antioxidant activity in grain of 23 winter wheat genotypes exposed to stress (artificial inoculation with spores of fungi from the genus Fusarium or chemical protection) were analysed. Concentrations of ergosterol confirm significantly higher levels of contamination with microscopic fungi in inoculated wheat samples in comparison to the control and chemically protected samples. The highest concentrations of bound phenolic acids were recorded in inoculated samples while the control and chemically protected samples did not differ significantly. Chromatographic analysis of contents of 12 bound phenolic acids showed that significant differences were found for contents of ferulic, synapic, t-cinnamic and 4-hydroxybenzoic acids in experimental variants. Stepwise discriminatory analysis based on the contents of selected bound phenolic acids antioxidant activity and free phenolic acids led to a complete separation of the investigated populations of the experimental groups. The statistical analysis confirmed that free phenolic acids are the most significant factors in resistance mechanisms as the first line of defence together with their antioxidant action, followed by the synergistic effect of exogenous bound phenolic acids: ferulic, synapic, t-cinnamic and 4-hydroxybenzoic acids.

Application of Artificial Neural Networks to Analyze the Concentration of Ferulic Acid, Deoxynivalenol, and Nivalenol in Winter Wheat Grain

“…The influence of the variety on the ferulic acid content is confirmed by numerous studies; however, differences in the examined content of this acid are observed [60][61][62]. Stuper-Szablewska et al [21] showed that the average content of ferulic acid under control conditions was 844 mg/kg, 780 mg/kg, and 771 mg/kg in the years of the study. After inoculation, these values increased to 2248 mg/kg, 2574 mg/kg, and 3145 mg/kg, respectively [21].…”

“…Stuper-Szablewska et al [21] showed that the average content of ferulic acid under control conditions was 844 mg/kg, 780 mg/kg, and 771 mg/kg in the years of the study. After inoculation, these values increased to 2248 mg/kg, 2574 mg/kg, and 3145 mg/kg, respectively [21].…”

“…In turn, high correlations between field infestation and DON content in the grain were observed by Miedaner et al [52] and Mesterházy [51]. The content of DON and NIV has been presented in detail in the publication Stuper-Szablewska et al [21]. The content of DON was not dependent on the index disease calculated on the basis of the field observations.…”

“…The large range of variability of ferulic acid content in wheat varieties is also caused by the impact of environmental conditions and the interaction of the genotype with the environment [63]. An additional factor affecting the content of this acid is the occurrence of infection [21,64].…”

“…In addition to genetic studies on wheat resistance to Fusarium, research has also been conducted on the biochemical aspects of plant responses to a massive pathogen attack. Based on the literature sources [18,19] and our own [20,21] research, it was found that antioxidative processes based on the significantly increased biosynthesis of the low-molecular antioxidants of the plant have a significant impact on pathogenesis, and constitute the first line of defense against pathogens. Based on the concentration of the selected phenolic acids, including ferulic acid, it is possible to assess the degree of disease risk at an early stage of pathogenesis [20,22].…”