Metabolic Profiling Identifies Changes in the Winter Wheat Grains Following Fusarium Treatment at Two Locations in Croatia

Abstract

Fusarium head blight (FHB) is one of the most dangerous diseases of winter wheat, resulting in reduced grain yield and quality, and production of mycotoxins by the Fusarium fungi. In the present study, changes in the grain metabolomics of winter wheat samples infected with Fusarium spp. and corresponding non-infected samples from two locations in Croatia were investigated by GC-MS. A Mann-Whitney test revealed that 24 metabolites detected were significantly separated between Fusarium-inoculated and non-infected samples during the variety by treatment interactions. The results confirmed that in grains of six FHB-resistant varieties, ten metabolites were identified as possible resistance-related metabolites. These metabolites included heptadecanoic acid, 9-(Z)-hexadecenoic acid, sophorose, and secolaganin in grains of FHB-resistant varieties at the Osijek location, as well as 2-methylaminomethyltartronic acid, maleamic acid, 4-hydroxyphenylacetonitrile, 1,4-lactonearabinonic acid, secolaganin, and alanine in grains of FHB-resistant varieties at the Tovarnik location. Moreover, on the PCA bi-plot, FHB-susceptible wheat varieties were closer to glycyl proline, decanoic acid, and lactic acid dimer that could have affected other metabolites, and thus, suppressed resistance to FHB. Although defense reactions were genetically conditioned and variety specific, resulting metabolomics changes may give insight into defense-related pathways that could be manipulated to engineer plants with improved resistance to the pathogen.

Keywords: Fusarium head blight; GC-MS; biotic stress; metabolic profiling; winter wheat.

Figure 1

Tree diagram of agglomerative hierarchical clustering of 25 winter wheat varieties based on different grain metabolites and varietal resistance to Fusarium in two treatments (naturally infected or controlled treatment-C and inoculated or Fusarium treated-F) at both locations. Os—Osijek, Tov—Tovarnik, C1—cluster 1, C2—cluster 2.

Figure 2

Scree plot showing eigenvalues in response to number of components for the estimated variables of winter wheat varieties at both locations.

Figure 3

PCA bi-plot of 24 wheat metabolites in the grains and varietal resistance to Fusarium of 25 winter wheat varieties under controlled and Fusarium treatments at both locations.

Figure 4

Graphical Spearman correlation matrix of 24 wheat metabolites in grains and varietal resistance to Fusarium. Spearman correlation r values were determined using GraphPad Prism 9.4.1. Colors are added for better visualization. The colors span from dark blue to dark red, where dark blue denotes an r value of 1 and dark red indicates an r value of −1.