Department of Botany and Nature Protection, University of Warmia and Mazury in Olsztyn Plac Łódzki 1, 10-727 Olsztyn, Poland.
Department of Chemistry, Poznan University of Life Sciences, Wojska Polskiego 75, 60-637 Poznan, Poland.
Toxins (Basel). 2018 Nov 24;10(12):492. doi: 10.3390/toxins10120492.
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 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 genes (4, 5, and 10), 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 -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.
杀菌剂的应用仍然是农业生态系统中防治真菌病的最广泛方法之一。然而，杀菌剂的广泛使用对人类健康和自然环境构成了危害，并且并不总是能确保有效减少食品和饲料中的真菌毒素。如今，由于真菌毒素污染主食而带来的威胁不断增加，这刺激了人们开发替代策略来控制植物病原菌。大量的工作都集中在鉴定抑制植物病原菌产生真菌毒素的植物源性化合物上。L-焦谷氨酸最近被认为在大麦对产毒镰刀菌的反应中发挥了作用。考虑到这一点，我们研究了不同水平的 L-焦谷氨酸对各种严格意义上的 sensu stricto 菌株在固体 YES（酵母提取物蔗糖）培养基上的反应。L-焦谷氨酸降低了所有被检测菌株中三萜烯的积累。针对诱导三萜烯生物合成的基因（4、5 和 10）的基因表达研究表明，L-焦谷氨酸在转录水平上抑制了真菌毒素的产生。除了对真菌毒素产生的抑制作用外，L-焦谷氨酸对真菌苯丙素类化合物的产生也表现出不同的、浓度相关的影响。在 100 和 400 µg/g L-焦谷氨酸的存在下，大多数真菌来源的酚酸的积累减少。然而，更高剂量（800 µg/g）的 L-焦谷氨酸增加了培养基中 -肉桂酸的积累。在 L-焦谷氨酸存在的情况下，真菌来源的柚皮素的积累增加。而对于槲皮素、芹菜素、木犀草素和山奈酚，得到了相反的结果，在 100 和 400 µg/g L-焦谷氨酸处理的样品中，它们的积累减少，而最高浓度的 L-焦谷氨酸（800 µg/g）似乎诱导了它们的生物合成。本研究的结果为参与研究抗镰刀菌的育种者提供了新的见解。
