Bioscience Evidence 2025, Vol.15, No.6, 303-312 http://bioscipublisher.com/index.php/be 309 7 Risk assessment of Genetically Modified potatoes resistant to Late blight 7.1 Pathogen evolution risk and resistance persistence A core concern in promoting genetically modified (GM) potatoes with late blight resistance is the possible evolution of the pathogen Phytophthora infestans (late blight pathogen). With the advancement of genetic engineering technology, researchers can "stack" multiple R genes from wild potatoes, which can recognize the key effectors of pathogens. Because pathogenic bacteria must simultaneously break through multiple defense mechanisms, the probability of this situation occurring in natural populations is extremely low (Berindean et al., 2024). Transgenic potatoes carrying two to three superimposed R genes exhibited complete or near-complete resistance in multiple seasons and different environments, and showed no signs of resistance failure even under conditions of high disease stress. However, the evolutionary ability of late blight bacteria remains a potential risk, especially in areas with high diversity of pathogenic bacteria or inadequate resistance management strategies. 7.2 Ecological risk: impact on non-target organisms and soil microorganisms The environmental safety assessment of genetically modified late blight resistant potatoes mainly focuses on whether they will affect non-target organisms, including beneficial insects, other pests and soil microbial communities. Multiple trials and biosafety assessments have shown that Introducing disease-resistant genes (such as the RB gene fromSolanum bulbocastanum) does not affect non-target pests (such as Alternaria) Adverse effects are caused by solani, leaf miners, potato borer, aphids, mites, etc. Or beneficial soil microorganisms (such as nitrogen-fixing bacteria, phosphorus-solubilizing bacteria, soil fungi) (Ambarwati et al., 2022). There was no significant difference in the quantity and diversity of soil bacteria and fungi between GM potato and non-GM varieties. These results were verified in multiple locations and multiple years (Krause et al., 2020). The use of fungicides has a more significant impact on certain soil microbial indicators than genetic modification itself, but this effect is not unique to GM varieties. 7.3 Gene mobility and biosecurity issues The genes of genetically modified potatoes do not transfer at a distance of more than 10 meters, and agricultural measures such as crop rotation, isolated planting, and mechanical cleaning further reduce the risk (Forbes et al., 2023). Through fine molecual-level analysis of transgenic events, it can be ensured that only the target genes are transferred in, and there will be no accidental insertions such as vector skeleton fragments (Zarka et al., 2021). 8 Future Prospects and Breeding Strategies Searching for new resistance genes (R genes) remains a core task, and many wild Solanum plants provide rich genetic diversity for gene sources. Nowadays, effectoromics technology and genome-wide association analysis (GWAS) have greatly accelerated the discovery of resistance genes and quantitative resistance loci (QRLs). GWAS has identified resistance hotspots on chromosome 11 and screened out excellent materials that can be used for backcrossing breeding, helping to broaden the genetic basis of disease-resistant breeding. Unlike traditional genetic modification, gene editing can achieve precise alterations, such as knocking out susceptibility genes (S genes) or repairing unfavorable mutations, and it does not require the introduction of exogenous DNA. Editing S genes such as StDMR6-1 and StCHL1 can endow potatoes with strong resistance without affecting plant growth and yield. Therefore, it is very suitable for breeding. Editing metabolic pathway genes such as StCCoAOMT can also enhance resistance by strengthening the cell wall or increasing the accumulation of defense metabolites. RNA interference (RNAi) and host-induced gene silencing (HIGS) have further enriched the means of controlling Phytophthora infestans, providing more options for disease-resistant breeding. A large number of field trials have shown that potatoes carrying two or more R genes simultaneously exhibit broad-spectrum and persistent resistance, maintaining good performance even when the local P. infestans population is complex and variable. The advantage of modular stacking lies in that breeders can combine different
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