Bioscience Evidence 2025, Vol.15, No.6, 303-312 http://bioscipublisher.com/index.php/be 304 through mutation or recombination (Rakosy-Tican et al., 2020). This study examines the field performance of transgenic potato materials resistant to late blight obtained by introducing and superimposing Rpi genes from wild Solanum species, including multi-year field trials, molecular identification of resistance gene integration, and environmental and economic impact assessment. By integrating the latest advancements in genetic engineering, discovery of resistance genes and field validation, this study aims to provide references for future breeding plans and policy formulation, and promote more sustainable strategies for the prevention and control of late blight in potatoes. 2 Literature Review: Resistance Genes and Genetic Improvement Strategies 2.1 Major Rpi resistance genes and their sources In the long-term search for potatoes' persistent resistance to late blight, researchers have discovered and utilized a variety of resistance (Rpi) genes, most of which are derived from wild Solanum plants. Among them, the more important genes include RB (also known as Rpi-blb1), Rpi-blb2, Rpi-vnt1.1 and Rpi-amr1. RB and Rpi-blb2 are from the Mexican wild species Solanum bulbocastanum, which has broad-spectrum resistance to Phytophthora infestans. Rpi-vnt1.1 is derived from the wild species Solanum venturii in South America and has shown strong resistance in both laboratory and field trials. The newer Rpi-amr1 and Rpi-amr3 were cloned from Solanum americanum. The main mechanism of action of these genes is to recognize the effector of pathogenic bacteria and then activate the immune response of plants. Through conventional breeding or biotechnological means, these genes have been successfully introduced into cultivated potato varieties (Witek et al., 2020). 2.2 Theoretical basis and advantages of polygene stacking Due to the rapid variation and high genetic diversity of P. infestans, single resistance genes in commercial potato varieties are often broken through. Multi-gene stacking (pyramiding) is the combination of multiple Rpi genes that recognize effectors of different pathogenic bacteria into the same variety. Materials with stacked two or more Rpi genes have stronger resistance and are more stable than those with only a single gene (Wang et al., 2025). After the simultaneous introduction of RB, Rpi-blb2 and Rpi-vnt1.1 into some African highland potato varieties, complete disease resistance was demonstrated in the field for many consecutive years even without the use of fungicides. Multi-gene stacking can activate plant defense pathways more comprehensively and strongly (Zhao et al., 2025). 2.3 Comparison of transgenic, cisgenic and molecular marker-assisted selection (MAS) breeding transgenic (transgenic) can introduce Rpi genes from unrelated species into potatoes, with the widest range of gene sources. However, this method often encounters problems such as strict supervision and low public acceptance. cisgenic genes only use genes from "hybridizable potato relatives" and are more likely to be recognized in terms of safety and consumer acceptance. Meanwhile, it still retains the advantages of genetic engineering, such as precise stacking of multiple R genes and short breeding cycle, etc. Marker-assisted selection (MAS) utilizes molecular markers closely linked to disease-resistant genes to accelerate the screening of resistant offspring in conventional breeding. MAS has a low cost and is relatively easy to be accepted. However, it is limited by the fact that donors and recipients must be genetically compatible, and it requires a long backcrossing and selection time (Meade et al., 2020; Beketova et al., 2021; Angmo et al., 2023). 2.4 Genetic diversity of late blight bacteria Phytophthora infestans and the challenges of resistance breeding P. infestans have a large genetic diversity and strong adaptability, which is one of the biggest challenges faced by resistance breeding. Pathogenic bacteria can rapidly produce new pathogenic types, rendering many single Rpi genes (such as those fromS. demissum) ineffective. Studies on pathogen populations from Africa, Europe and the Americas have shown that in some regions, the single clone type is dominant, but in some regions, the microbiota is very diverse (Rogozina et al., 2023). The dynamic changes in pathogenic bacteria populations indicate that continuous monitoring, the constant discovery of resistance genes, and the integration of multiple resistance mechanisms in breeding are of great significance. Combining Rpi gene stacking with pathogen monitoring and integrated pest and disease management is an effective approach to addressing the evolving P. infestans.
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