Resistance-Related l-Pyroglutamic Acid Affects the Biosynthesis of Trichothecenes and Phenylpropanoids by F. graminearum Sensu Stricto

Abstract

Fungicide application remains amongst the most widely used methods of fungal control in agroecosystems. However, the extensive use of fungicides poses hazards to human health and the natural environment and does not always ensure the effective decrease of mycotoxins in food and feed. Nowadays, the rising threat from mycotoxin contamination of staple foods has stimulated efforts in developing alternative strategies to control plant pathogenic fungi. A substantial effort is focused on the identification of plant-derived compounds inhibiting mycotoxin production by plant pathogenic fungi. l-Pyroglutamic acid has recently been suggested as playing a role in the response of barley to toxigenic Fusaria. Considering the above, we studied the response of various strains of F. graminearum sensu stricto to different levels of l-pyroglutamic acid on solid YES (yeast extract sucrose) media. l-Pyroglutamic acid decreased the accumulation of trichothecenes in all examined strains. Gene expression studies addressing Tri genes (Tri4, Tri5, and Tri10), which induce the biosynthesis of trichothecenes, revealed the production of mycotoxins by l-pyroglutamic acid to be inhibited at the transcriptional level. Besides inhibitory effects on mycotoxin production, l-pyroglutamic acid exhibited variable and concentration-related effects on phenylpropanoid production by fungi. Accumulation of most of the fungal-derived phenolic acids decreased in the presence of 100 and 400 µg/g of l-pyroglutamic acid. However, a higher dose (800 µg/g) of l-pyroglutamic acid increased the accumulation of trans-cinnamic acid in the media. The accumulation of fungal-derived naringenin increased in the presence of l-pyroglutamic acid. Contrasting results were obtained for quercetin, apigenin, luteolin, and kaempferol, the accumulation of which decreased in the samples treated with 100 and 400 µg/g of l-pyroglutamic acid, whereas the highest l-pyroglutamic acid concentration (800 µg/g) seemed to induce their biosynthesis. The results obtained in this study provide new insights for breeders involved in studies on resistance against Fusaria.

Chemically Defined Lactobacillus plantarum Cell-Free Metabolites Demonstrate Cytoprotection in HepG2 Cells through Nrf2-Dependent Mechanism

“…In the present study, we identified the optimum growth parameter of L. plantarum against several biotic and abiotic stress conditions, grew the bacteria under such conditions and utilized the cell-free metabolome for cell-based assays. Among the highly abundant metabolites, the antioxidant effects of 5-oxoproline (aka pyroglutamic acid) [ 27 ], butanedioic acid (i.e., succinic acid) [ 28 ], N , N -dimethylglycine [ 29 ], etc. have already been established.…”

Design, Synthesis, and Evaluation of Novel L-Pyroglutamic Acid Derivatives as Potent Antifungal Agents

“…A recent investigation revealed that the synthetic L-pyroglutamic acid analogs have been proved to be novel fungicide candidates to fight F. solani and G. candidum, two strains that are known to pose health risks related to major barrier breaks among people with weak immune systems [8]. Previous studies stated that the application of pyroglutamic acid and its derivatives is capable of increasing lettuce yield [9], conferring protection to bread wheat against Zymoseptoria tritici [7], affecting the biosynthesis of trichothecenes and phenylpropanoids [10] stimulating DNA synthesis in rat primary hepatocytes [11], showing anti-HIV-1 and anti-HCV activity [12], exhibiting antioxidant activity and anti-inflammatory activity [13], showing selective Gram-negative antibacterial activity and antiplatelet activity [14,15], and acting as a new farnesyl transferase inhibitor [16]. In our previous research, it was found that L-pyroglutamic acid extracted from Disporopsis Aspera Engl.…”