Sugar and Free Amino Acid Contents in Winter Wheat Flour Under Fusarium Head Blight Treatment and Natural Infection

Abstract

Fusarium head blight (FHB) is one of the most devastating diseases in wheat. Besides its negative impact on grain yield, FHB also negatively influences quality. Changes in sugar and free amino acid content were analyzed in flour from Fusarium-infected and non-infected grains of six wheat varieties differing in Fusarium resistance. The concentrations of sugars and free amino acids were determined using a high-performance liquid chromatography device. In flour from FHB-infected grains, the average total amount of fructose, glucose, maltose, total sugars, and total reducing sugars was significantly increased, compared to non-treated flour from the Tika Taka variety, which was the most FHB-susceptible. The total content of free amino acids in flour from FHB-infected varieties increased in proportion to their susceptibility. In Tika Taka, there was a significant increase in free amino acid content of about 46%, while a significant decrease of 16% was observed in the highly resistant Vulkan variety. A highly significant correlation was established between the degree of FHB susceptibility and the content of aspartic acid, glutamic acid, glutamine and histidine, glycine, alanine, methionine, valine, tryptophan, phenylalanine, leucine, and threonine. Most amino acids had strong positive correlations with each other, but among the sugars, only fructose and glucose content showed a strong positive correlation with specific amino acids that were induced by Fusarium infection. Overall, it can be concluded that FHB-susceptible varieties have a high risk of FHB infection, which results in the hydrolysis of sucrose into fructose and glucose, together with an increase in free amino acids, which deteriorates the quality of wheat.

Keywords: Fusarium; free amino acids; sugars; wheat.

Figure 1

General (A) and type I (B) resistance in six winter wheat varieties (Vulkan, Kraljica, Galloper, Golubica, El Nino, and Tika Taka) as determined in terms of area under disease progress curve (AUDPC). Bars represent mean values of two independent biological replicates ± SD. Lowercase letters indicate significant difference among varieties (p < 0.05).

Figure 2

Content of fructose (A), glucose (B), sucrose (C), maltose (D), total sugars (E), and total reducing sugars (F) in flour from six winter wheat genotypes (Vulkan, Kraljica, Galloper, Golubica, El Nino, and Tika Taka) with natural infection and Fusarium inoculation. Bars represent means of four independent biological replicates ± SD. Lowercase letters indicate significant differences between treatments in each variety, while capital letters indicate significant differences between varieties in each type of treatment, i.e., natural and artificial infection (p < 0.05).

Figure 3

Total amino acid content in flour from six winter wheat genotypes (Vulkan, Kraljica, Galloper, Golubica, El Nino, and Tika Taka) with natural infection and Fusarium inoculation. Bars represent means of two independent biological replicates ± SD. Lowercase letters indicate significant differences between treatments in each variety, while capital letters indicate significant differences between varieties in each type of treatment, i.e., natural and artificial infection (p < 0.05).

Figure 4

The content of free amino acids—aspartic acid (A), glutamic acid (B), glycine (C), alanine (D), arginine (E), and asparagine (F)—in flour from six winter wheat genotypes (Vulkan, Kraljica, Galloper, Golubica, El Nino, and Tika Taka) with natural infection and Fusarium inoculation. Bars represent means of two independent biological replicates ± SD. Lowercase letters indicate significant differences between treatments in each variety, while capital letters indicate significant differences between varieties in each type of treatment, i.e., natural and artificial infection (p < 0.05).

Figure 5

The content of free amino acids—glutamine and histidine (A), methionine (B), valine (C), and tryptophan (D)—in flour from six winter wheat genotypes (Vulkan, Kraljica, Galloper, Golubica, El Nino, and Tika Taka) with natural infection and Fusarium inoculation. Bars represent mean values of two independent biological replicates ± SD. Lowercase letters indicate significant differences between treatments in each variety, while capital letters indicate significant differences between varieties in each type of treatment, i.e., natural and artificial infection (p < 0.05).

Figure 6

The content of free amino acids—phenylalanine (A), isoleucine (B), leucine (C), and threonine (D)—in flour from six winter wheat genotypes (Vulkan, Kraljica, Galloper, Golubica, El Nino, and Tika Taka) with natural infection and Fusarium inoculation. Bars represent mean values of two independent biological replicates ± SD. Lowercase letters indicate significant differences between treatments in each variety, while capital letters indicate significant differences between varieties in each type of treatment, i.e., natural and artificial infection (p < 0.05).

Figure 7

Correlation analysis of the investigated content of sugars and amino acids in flour with natural infection (A) and the investigated content of sugars, amino acids, and general and type I Fusarium resistance in the Fusarium treatment (B). *,**—significant correlation at 0.05 and 0.01.

Figure 8

Total monthly rainfall (mm) and average temperature (°C) during the growing season from October 2023 to June 2024, as well as during the growing season for the period 1990–2024 taken as the multi-year average.