Plant Gene and Traits 2024, Vol.15, No.4, 174-183 http://genbreedpublisher.com/index.php/pgt 177 develop wheat varieties with improved powdery mildew resistance through marker-assisted selection (MAS) and genetic engineering approaches (Zhang et al., 2015). 4 Application of the MlWE74Gene in Wheat Breeding 4.1 Marker-assisted selection breeding of the MlWE74 resistance gene Marker-assisted selection (MAS) is a powerful tool in modern plant breeding, allowing for the precise incorporation of desirable traits such as disease resistance (Yang et al., 2008; Miedaner and Korzun, 2012; Fang, 2024). The MlWE74 gene, derived from wild emmer wheat, has been identified as a key resistance gene against powdery mildew in wheat. Genetic analysis has shown that MlWE74 is controlled by a single dominant gene, making it an ideal candidate for MAS. The gene has been mapped to the terminal region of chromosome 2BS, flanked by markers WGGBD412 and WGGBH346 within a 0.25 cM genetic interval. The co-segregated marker WGGBD425 is particularly useful for the marker-assisted transfer of MlWE74 into elite wheat cultivars, facilitating the development of resistant lines with desirable agronomic traits (Zhu et al., 2021). 4.2 Application of transgenic and gene editing technologies in breeding Transgenic and gene editing technologies offer innovative approaches to enhance disease resistance in wheat. The functional validation of resistance genes like MlWE74 can be achieved through transgenic assays and gene editing techniques such as CRISPR/Cas9 (Mushtaq et al., 2019). For instance, the Pm5e gene, another powdery mildew resistance gene, was validated using transgenic assays and loss-of-function mutants, demonstrating the potential of these technologies in confirming gene function and facilitating their use in breeding programs (Xie et al., 2020). By applying similar methodologies, the MlWE74 gene can be precisely edited or introduced into susceptible wheat varieties, thereby conferring resistance to powdery mildew and improving overall crop resilience. 4.3 Innovative utilization of disease-resistant germplasm The utilization of disease-resistant germplasm is crucial for sustainable wheat production (Kumar et al., 2022). Wild emmer wheat, the source of the MlWE74 gene, represents a valuable genetic resource for breeding programs aimed at enhancing disease resistance (Zhu et al., 2021). The identification and characterization of resistance genes from diverse germplasm, such as the Pm10V-2 gene from a wheat breeding line, highlight the importance of exploring and utilizing genetic diversity (Ma et al., 2017). By incorporating genes like MlWE74 into breeding programs, it is possible to develop new wheat varieties with enhanced resistance to powdery mildew, thereby reducing the reliance on chemical fungicides and promoting sustainable agricultural practices. 5 Phenotypic Evaluation and Breeding Performance of the MlWE74Gene 5.1 Field performance of wheat varieties resistant to powdery mildew The field performance of wheat varieties carrying the MlWE74 gene has shown promising results in terms of resistance to powdery mildew. The gene, derived from wild emmer wheat (Triticum turgidumvar. dicoccoides), has been successfully transferred to hexaploid wheat line WE74, which exhibits strong resistance to the disease. This resistance is controlled by a single dominant gene, MlWE74, which has been fine-mapped to a specific region on chromosome 2BS. The geographical distribution of MlWE74 indicates its prevalence in regions with favorable conditions for powdery mildew, such as Rosh Pinna and Amirim in northern Israel, suggesting its potential effectiveness in similar environments globally (Zhu et al., 2021). Field trials have demonstrated that wheat varieties with the MlWE74 gene maintain high levels of resistance throughout various growth stages. This is consistent with findings from other studies where resistance genes derived from wild emmer wheat, such as MlIW39, have shown robust performance against multiple isolates of Blumeria graminis f. sp. tritici (Bgt) (Qiu et al., 2021). The use of marker-assisted selection (MAS) has facilitated the efficient transfer of MlWE74 into elite cultivars, enhancing their resistance profiles without compromising agronomic performance (Qiu et al., 2021; Zhu et al., 2021). 5.2 Correlation analysis between disease resistance and agronomic traits Correlation analysis between disease resistance conferred by the MlWE74 gene and various agronomic traits is crucial for understanding its overall impact on wheat cultivation. Studies have shown that the introduction of resistance genes like MlWE74 does not adversely affect key agronomic traits such as yield, plant height, and grain
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