Molecular Microbiology Research 2024, Vol.14, No.4, 162-170 http://microbescipublisher.com/index.php/mmr 163 recent studies (Tsers et al., 2021). The susceptibility of rye to this pathogen has led to substantial crop losses, highlighting the need for improved disease resistance. Another significant fungal disease in rye is powdery mildew, caused by Blumeria graminis f. sp. tritici. The introgression of resistance genes from rye into wheat, such as the Pm17 gene, has been a common strategy to combat this disease. However, the effectiveness of these resistance genes can be limited by the ancient variation of the corresponding fungal effector genes, which predate the introgression and can lead to rapid resistance breakdown. The historical context of rye diseases also includes the impact of climate change, which has been shown to exacerbate the emergence and spread of fungal pathogens. Environmental pressures resulting from climate change can lead to the adaptation of fungi to new conditions, increasing their pathogenicity and geographic range (Nnadi and Carter, 2021). This has been observed with various fungal species, which have become more problematic in recent decades due to changing climate conditions. 2.2 Evolution of disease resistance in rye The evolution of disease resistance in rye has been a critical area of research, particularly in the context of breeding programs aimed at enhancing phytoimmunity. Studies have identified several rye genotypes with non-specific resistance to multiple fungal diseases. For instance, research conducted on winter rye genotypes has revealed varieties with slow rusting traits and high resistance to septoria and other fungal infections (Shchekleina and Sheshegova, 2023). These resistant varieties, such as 'Rossiyanka 2', have been crucial in breeding programs to develop new rye cultivars with improved disease resistance. The identification and characterization of resistance genes have also played a significant role in the evolution of disease resistance in rye. The Pm17 and Pm8 resistance genes, originally introgressed from rye into wheat, demonstrate the ancient diversity and evolutionary divergence of resistance genes in cereal crops (Singh et al., 2018). These genes have been isolated and functionally validated, providing valuable insights into the genetic basis of disease resistance and guiding future breeding efforts. The development of novel translocation lines, such as the wheat-rye 1RS·1BL translocation lines, has contributed to the enhancement of disease resistance in rye. These lines exhibit high resistance to stripe rust and other fungal pathogens, offering new genetic resources for wheat and rye improvement programs (Ren et al., 2022). 3 Fungal Diseases Affecting Rye 3.1 Ergot disease Ergot disease, caused by fungi in the genus Claviceps, is a significant concern for rye cultivation. The most notable species, Claviceps purpurea, infects the ovaries of rye flowers, replacing seeds with toxic sclerotia. This disease has been documented in Europe since the early Middle Ages and poses severe health risks due to the alkaloids produced by the fungus, which can affect both humans and animals. In Canada, ergot is a grain-grading factor, impacting grain quality and safety due to the presence of ergot alkaloids (Walkowiak et al., 2022). Breeding efforts have identified several winter rye cultivars with moderate resistance to ergot, which can be utilized to develop more resistant varieties. 3.2 Rusts and smuts Rusts and smuts are other significant fungal diseases affecting rye. Rust diseases, such as stripe rust caused by Puccinia striiformis, have historically been a major threat to cereal crops. Although primarily a concern for wheat, rust fungi can also affect rye. The management of rust diseases often involves the use of fungicides and the development of resistant cultivars (Cook et al., 2021). Smut diseases, caused by fungi like Ustilago species, can also impact rye, leading to significant yield losses. 3.3 Modern fungal disease management 3.3.1 Fungicide application strategies Fungicide application remains a critical component of managing fungal diseases in rye. However, the efficacy of fungicides can be limited and weather-dependent, particularly for diseases like ergot (Miedaner and Geiger, 2015).
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