Molecular Pathogens, 2025, Vol.16, No.2, 77-86 http://microbescipublisher.com/index.php/mp 83 dependence on chemical control. In addition, molecular technologies such as CRISPR-Cas9 and RNA interference have also begun to be used to study how to block the replication of viruses in the grape body. Early greenhouse experiments show that genetic engineering is expected to become an effective means of disease resistance. For example, in South Africa and California, some pilot projects combine "viral-free materials" and "resistant varieties", and the incidence of GLRaV has decreased significantly, and both production and economic benefits have also improved (Koledenkova et al., 2022). 7.3 Lessons from field trials across regions Field experiments from all over the world provide a lot of valuable experience. For example, there have been research on using oligostyrene extracted from vine by-products to prevent and treat downy mildew. This substance can prevent the movement and formation of bacterial spores and can also stimulate the grapes’ self-defense ability (Taillis et al., 2022). Another example is the transcriptome study of Shanxi Grape. The study found that when encountering bacteria, grapes activate some important defense genes and pathways, such as MAPK and ROS signals. These pathways are particularly critical when the disease begins (Li et al., 2015). These experiments show that if the molecular-level research results can be applied to field practices, the grapes can better improve their disease resistance. 8 Breeding Strategies for Disease Resistance 8.1 Marker-assisted breeding for enhanced resistance Marker-assisted selection (MAS) is a very practical tool in grape breeding. It can help us find seedlings with disease-resistant genes in the early stages. This approach is particularly useful for localizing some important resistance sites, such as Rpv, Ren, and Run. These sites have a lot to do with resistance to downy mildew and powdery mildew. To save time and cost, researchers have developed a new approach. It does not require purifying DNA, but only multiple PCR technology can detect multiple samples at the same time. This method is efficient and inexpensive and has been successfully applied in thousands of samples (Agurto et al., 2017). It has become a reliable method for improving disease resistance in many breeding programs. 8.2 Integrating resistance traits into high-yielding varieties To make grapes both high yield and disease resistant, multiple resistance genes need to be used together. For example, adding two anti-powder mildew genes, RUN1 and REN1, to the same variety, will have a very good effect. This “superposition” approach can strengthen the grape’s defense capabilities and reduce the chances of pathogens’ evolution of drug resistance. Such grape plants usually produce more reactive oxygen species and can also activate some defense genes. This approach is particularly worth considering for those who want to cultivate varieties that are both yielding and disease-resistant (Possamai et al., 2024). 8.3 Role of genome editing and CRISPR in developing resistant cultivars Now, gene editing technology is changing the way grape breeding is being bred. In particular, the CRISPR/Cas9 system, which uses it to transform certain “susceptible genes” of grapes, such as VvMLO3, has been used to enhance resistance to powdery mildew. The advantage of this technology is that it can accurately modify the target gene without introducing foreign DNA. This means that we can only change where we want to change, and it will not affect other traits. Experiments show that these edited grapes can produce reactive oxygen species faster and can also initiate cell death programs to prevent the spread of bacteria. All of these changes make grapes more resistant to disease (Wan et al., 2020; Pirrello et al., 2022). Therefore, CRISPR not only improves disease resistance, but also retains the original good traits of grapes, which is very promising. Acknowledgments Thanks Ms. Chen from the Hainan Institution of Biotechnology for her assistance in references collection and discussion for this work completion. Conflict of Interest Disclosure The author affirms that this research was conducted without any commercial or financial relationships that could be construed as a potential conflict of interest.
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