Oat (Avena sativa L.) is a widely cultivated cereal crop valued for both its nutritional benefits and agricultural versatility. However, oat production is increasingly challenged by powdery mildew, which is caused by Blumeria graminis f. sp. avenae (Bga) and can lead to considerable yield losses. Genetic resistance remains the most sustainable and environmentally friendly method of disease control. This study aimed to evaluate the effectiveness of 14 oat genotypes carrying known resistance genes (Pm1–Pm12) and Avena strigosa accessions against Bga populations collected across four regions of Poland between 2021 and 2023. Host–pathogen assays were used to assess resistance levels, virulence frequency, and pathotype diversity. Resistance genes were categorized into three groups based on performance: highly effective (Pm2, Pm4, Pm5, Pm7 in APR122 and A. strigosa), variably effective (Pm7 in ‘Canyon’ and Pm9–Pm12), and moderately effective (Pm1, Pm3, Pm6 and Pm3+8). Pathogen populations exhibited decreasing virulence complexity and diversity over time, with substantial regional variation. There were few dominant pathotypes, but most were rare and transient. This study confirms the long-term effectiveness of several resistance genes and the necessity of continuous resistance monitoring. It supports the use of gene pyramiding to ensure durable, regionally adapted protection. These results highlight the importance of combining resistance breeding with integrated disease management to ensure sustainable oat production under changing environmental conditions.

Climate change forces agriculture to face the rapidly growing virulence of biotrophic fungal pathogens, which in turn drives researchers to seek new ways of combatting or limiting the spread of diseases caused by the same. While the use of agrochemicals may be the most efficient strategy in this context, it is important to ensure that such chemicals are safe for the natural environment. Heterocyclic compounds have enormous biological potential. A series of heterocyclic scaffolds (1,3,4-thiadiazole, 1,3-thiazole, 1,2,4-triazole, benzothiazine, benzothiadiazine, and quinazoline) containing 2,4-dihydroxylaryl substituents were investigated for their ability to inhibit the growth and development of biotrophic fungal pathogens associated with several important cereal diseases. Of the 33 analysed compounds, 3 were identified as having high inhibitory potential against Blumeria and Puccinia fungi. The conducted research indicated that the analysed compounds can be used to reduce the incidence of fungal diseases in cereals; however, further thorough research is required to investigate their effects on plant–pathogen systems, including molecular studies to determine the exact mechanism of their activity.

Oat (Avena sativa L.) is one of the most important plant-based raw materials used in agriculture, yet its cultivation is threatened by various diseases, including powdery mildew (Blumeria graminis f. sp. avenae). Powdery mildew is a pathogenic fungus that infects oat leaves, leading to a reduction in both crop quality and yield. The fungus invades host plants by forming specialized infection structures that facilitate penetration of plant cells. As a result of infection, disturbances occur in plant metabolism, photosynthetic efficiency decreases, and tissue structure is altered. In response to pathogen invasion, the plant activates a range of defense mechanisms involving both physical and biochemical responses. Oat resistance to powdery mildew is governed by resistance (R) genes, which encode proteins responsible for pathogen recognition and the initiation of defense responses. These mechanisms include both genetic resistance and systemic reactions such as increased phytoalexin production and the activation of signaling pathways that restrict pathogen development. This article provides an overview of the current state of knowledge regarding the interactions between oat and powdery mildew, with a particular focus on the mechanisms underlying the plant’s response to infection.

Oat (Avena sativa L.) is a crop of significant economic and nutritional importance; however, its yield and quality can be substantially reduced by fungal diseases, including powdery mildew caused by Blumeria graminis f. sp. avenae (Bga). The aim of this study was to evaluate the phenotypic resistance of 110 genotypes of Lithuanian oat cultivars to powdery mildew using five pathogen isolates. Based on the results obtained, three genotypes with the highest level of resistance were selected. Among them, one cultivar—Delfin—carries the Pm7 resistance gene, as documented in the literature. The two remaining genotypes were subjected to detailed evaluation using 30 isolates for the purpose of resistance gene postulation, followed by molecular analysis employing STS (Sequence-Tagged Sites) and SCAR (Sequence Characterized Amplified Region) markers, aimed at identifying the presence of the Pm4, Pm5 and Pm7 genes, considered among the most desirable resistance genes against powdery mildew in oat. None of these genes were confirmed in the studied cultivars. The results obtained suggest that the observed resistance may be conferred by other as-yet-unidentified resistance genes. The studied genotypes may therefore represent a novel and valuable source of resistance to powdery mildew, useful in breeding programs aimed at improving disease resistance in oat.