Molecular Pathogens, 2025, Vol.16, No.2, 61-68 http://microbescipublisher.com/index.php/mp 63 3.2 Genomics of rapeseed and discovery of resistance genes Now, great progress has been made in genome research on rapeseed. Scientists can use genome-wide association analysis (GWAS) and other technologies to find genes related to disease resistance. For example, GWAS helped find several molecular markers related to resistance to black tibia, which are also related to immune function in Arabidopsis (Ding et al., 2019). Among rapeseed varieties in China and Canada, researchers have also found genolos to resist black shin, which is useful for future breeding efforts (Fu et al., 2020). There are also some genes like BnaC4.PR2, which are also related to the salicylic acid pathway, are helpful in fighting diseases and are a good reference gene resource for breeding. 3.3 Signal transduction pathways and regulatory networks of resistance genes The initiation and regulation of rapeseed disease-resistant genes cannot be separated from the help of signaling. Among them, the salicylic acid (SA) pathway is very critical. It can trigger system acquired resistance (SAR) and is the core part of the plant defense response. Experiments have found that if rapeseed is allowed to overexpress the GDSL1 gene of Arabidopsis, it will increase the SA level and reactive oxygen species (ROS) content in the body, thereby enhancing its resistance to sclerotinia stem rot (Ding et al., 2019). In addition, a gene called PGIP (polygalacturonidase inhibitor) from rice, such as OsPGIP6, can also help genetically modified rapeseed to resist sclerotinia stem rot. This protein protects plant cell walls from being decomposed by pathogens (Yin et al., 2022). These signaling pathways and regulatory networks are very important for cultivating rapeseed varieties that are resistant to multiple diseases. 4 Development and Utilization of Genetic Resources for Resistance in Rapeseed 4.1 Genetic diversity of rapeseed varieties and resistance gene pools Now, researchers have found many rapeseed varieties and disease-resistant genes that are useful for breeding. For example, a genome-wide association study (GWAS) found many SNP sites related to resistance to black tibia, which are distributed on multiple chromosomes (Fu et al., 2020). This shows that rapeseed has great genetic diversity and has many resources that can be used for disease-resistant breeding. In addition, by comparing disease-resistant and non-resistant rapeseed varieties, some genes that express different expressions (called DEGs) when the disease occurs. The differences in these genes can help us understand how rape resists bacteria and further improves its resistance to disease (Li et al., 2020). 4.2 Value of wild relatives in resistance breeding Some wild close relatives of rapeseed also contain many useful disease-resistant genes. These genes are of great help to improve the disease resistance of rapeseed. For example, after introducing the GDSL1 gene in Arabidopsis into rapeseed, it can significantly increase its resistance to sclerotinia stem rot. This shows that the genes of relative plants are very valuable resources. There are also researches that use the PGIPgene in rice (a protein that can inhibit the decomposition of bacteria into cell walls) to make genetically modified rapeseed. It was found that this rapeseed is also more resistant to sclerotinia stem rot (Zhou, 2024). Therefore, not only are wild close relatives, but other species' genes can also be used to help rapeseed enhance its disease resistance. 4.3 Application of gene editing technologies (e.g., CRISPR-Cas9) for improving resistance genes Now, there is also a gene editing technology called CRISPR-Cas9, which can also help us improve the disease resistance of rapeseed. By accurately modifying the homologous copies of certain key genes, researchers have created a new rapeseed variety that is more resistant to sclerotinia stem rot and grey mold (Zhang et al., 2021). Moreover, these modifications will not affect other important traits of rapeseed, such as yield or quality. This gene editing method is relatively flexible and can accurately tamper with the target gene. It is a promising method to improve rapeseed's disease resistance. 5 Strategies and Practices in Resistance Breeding 5.1 Application of marker-assisted selection (MAS) in resistance breeding Marker-assisted selection (MAS) is an important method in rapeseed disease-resistant breeding nowadays, especially when fighting stem rot like sclerotinia stem rot. Simply put, this method is to use some “molecular
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