Molecular Pathogens, 2025, Vol.16, No.5, 207-216 http://microbescipublisher.com/index.php/mp 212 some antiviral genes also show linked evolution. For example, pvr1 and pvr6 in peppers are located at adjacent loci and inherited together, suggesting functional differentiation that may be caused by gene duplication. Another perspective on the evolution of resistance genes is the correspondence with pathogenic mutations. For example, since the Tm-22 gene of tomato was used in TMV in the 20th century, although the virus has produced breakthrough strains, the overall resistance has been maintained for a long time. This may be attributed to the functional importance of the target recognized by Tm-22, which is difficult for the virus to circumvent through mutation without losing its pathogenicity (Rivera-Márquez et al., 2022). 5.3 Application potential of cross-species resistance genes The genetic relationship between different Solanaceae crops gives some resistance genes the potential to be transferred and exert effects across species. In fact, there has been a long history of attempts to apply antiviral genes from one crop to another. A classic example is the tobacco N gene, which was originally derived from cigarette tobacco and is resistant to TMV. It was later successfully transferred to tomatoes to create TMV-resistant tomato varieties. On the one hand, the use of transgenic means can break through the barrier of conventional hybrid incompatibility and realize the introduction of distant genes. If the potato Rx1 gene is transferred into tobacco that is highly susceptible to PVX, complete immunity to PVX can be obtained in Nicotiana benthamiana. This experiment has been verified under laboratory conditions (Richard et al., 2020). On the other hand, emerging gene editing and cross-species expression regulation technologies are also being explored. A research team from the Chinese Academy of Agricultural Sciences recently successfully activated resistance to cucumber mosaic virus (CMV) in tobacco by constructing a chimeric NLR receptor and inserting antiviral elements from Arabidopsis into the tobacco background. This result shows that immune modules of different species can be recombined and integrated to create new interdisciplinary disease resistance pathways (Du et al., 2024). 6 Resistance Regulatory Network and Signaling Pathways 6.1 Hormone signaling interactions Phytohormones play a central role in regulating disease resistance immunity, and crosstalk often occurs between different hormone pathways, which jointly determine the outcome of resistance. In the antiviral response, the salicylic acid (SA) and jasmonic acid (JA) pathways are regarded as the two dominant signals. It is generally believed that the SA pathway mediates resistance to biological infections, especially rust fungi, viruses, etc., while the JA/ethylene (ET) pathway mainly deals with chewing insects and necrotic pathogens. However, research on viral immunity has found that this binary division is not absolute. In many cases, the SA and JA pathways are involved and influence each other. For example, when TMV infects tobacco, HR triggered by the N gene is accompanied by a substantial increase in SA levels, which is necessary to establish systemically acquired resistance (SAR) (Zhu et al., 2014). Inhibiting SA synthesis makes plants more susceptible to TMV at high temperatures. In potato, reports indicate that abscisic acid (ABA) signaling may be involved in the regulation of extreme resistance responses. When comparing PVY-resistant varieties, it was found that the ABA levels and related genes of the resistant varieties changed significantly after infection. It is speculated that ABA may promote the nuclear translocation process required for resistance. In fact, one mechanism of wheat resistance to stripe rust under high temperature is the intervention of ABA signaling, indicating that ABA can play an active role in some immunity (Qian and Huang, 2025). 6.2 Transcription factors and downstream regulatory modules After resistance signals are initiated, plants coordinate defense gene expression through multiple transcription factors (TFs). Studies have shown that TFs such as WRKY, bZIP, and NAC play a central role in antiviral immunity. For example, tobacco WRKY8 and WRKY28 are induced by SA to activate PR genes, and pepper CaBP60a promotes SA synthesis to enhance disease resistance. Some TFs are also pathogenic targets. For example, the TSWV effector NSs can bind to pepper TCP21 and interfere with the JA/auxin pathway, and the Tsw gene can recognize and utilize this signal. The TF network also regulates cell wall reinforcement, programmed cell death, and accumulation of resistant metabolites. In systemic acquired resistance (SAR), NPR1 interacts with TGA factors to activate defense genes and achieve long-lasting resistance of the whole plant (Chen et al., 2019).
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