Molecular Pathogens, 2025, Vol.16, No.5, 236-245 http://microbescipublisher.com/index.php/mp 242 recognized by different Pik alleles (Maidment et al., 2021). By analyzing the crystal structure of the Pik/AVR-Pik complex, scientists identified a series of amino acid sites whose mutations can enhance or broaden the binding ability of Pik to effectors (Devanna et al., 2014). These findings provide theoretical guidance for cultivating broad-spectrum Pik-mediated resistance. In addition, some newly discovered major anti-blastogenic genes have different modes of action from classic NLRs. The Pi54 gene encodes a unique membrane-localized protein that is not thought to directly recognize effectors, but instead inhibits the negative regulatory pathway of cell death at the site of bacterial invasion, thereby reducing lesion expansion. 6.2 Functional network of Xa series of bacterial blight resistance genes The resistance of rice to bacterial blight is mainly controlled by the Xa series of genes. Currently, more than 40 genes have been discovered, half of which have been cloned. They can be divided into three categories: NLRs (such as Xa1, Xa2, etc.) recognize effectors and trigger cellular defense; receptor kinases (such as Xa21) sense pathogenic signals and activate PTI immunity; execution factors (such as Xa10, Xa27) initiate cell death under the induction of effectors. Different Xa genes have diverse mechanisms but convergent downstream pathways, which are often accompanied by PR protein expression, reactive oxygen species burst and lignin deposition (Ji et al., 2020). There is synergy between some genes, such as Xa1 and Xa2 jointly recognizing dual effectors, and Xa4 and Xa10 complementary regulating early and late resistance. Functional genomics revealed core genes shared by multiple Xa resistances (such as OsPR1, OsHI-XIP), as well as durable resistance formed by the superposition of multiple QTLs (Wang et al., 2017). 6.3 Disease resistance-related transcription factors and regulatory networks In the process of plant disease resistance signaling, transcription factors play a bridge role from signal to response. A large number of studies have identified members of the transcription factor family related to disease resistance in rice, such as WRKY, NAC, bZIP, AP2/ERF, MYB, etc. These transcription factors globally determine the intensity and scope of immune responses by regulating the expression of downstream defense genes. Taking the WRKY transcription factor as an example, OsWRKY45 is an important regulator of the rice SA signaling pathway. Its overexpression plants have improved resistance to bacterial blight and rice blast, but it is also accompanied by a certain weakening of growth. OsWRKY45 itself is regulated by several upstream factors (Xu et al., 2019), such as NPR1 and PB1, so WRKY45 is regarded as a node of SA-mediated resistance. Another WRKY family member, OsWRKY13, is at the intersection of the JA and SA pathways and is believed to play a role in coordinating brown planthopper resistance and rice blast resistance. Among the NAC transcription factor family, OsNAC4 is a factor known to induce programmed cell death and is involved in the allergic response to rice blast. Its overexpression can enhance blast resistance, but plants are prone to premature aging, so it should be used with caution. 7 Research on Environmental Interaction and Disease Resistance Stability 7.1 Differences in the expression of disease resistance genes in different ecological environments The effect of rice disease resistance genes is often affected by ecological and environmental conditions. The resistance expression of the same gene sometimes differs in different locations and under different cultivation conditions. The main reasons include changes in climatic factors, soil conditions, and local pathogenic bacteria populations. For example, many rice blast resistance R genes have reduced resistance under high temperature conditions. A classic case is that of the broad-spectrum blast resistance gene Pi54, when the daytime high temperature exceeds 30 °C, the plant's resistance to ear blast is significantly weakened, but it becomes highly disease-resistant at around 25 °C. Similarly, the recessive gene xa13 that resists bacterial leaf blight has reduced resistance under high-temperature and high-nitrogen fertilizer conditions, presumably because the pathogen is more likely to expand when the host metabolism is strong (Naing et al., 2025). On the other hand, there are also a few genes that are more prominent in resistance in certain environments. For example, the Xa7 gene can still maintain strong resistance to bacterial blight at high temperatures (above 30 °C), even better than normal temperature conditions. Studies speculate that the defense response induced by Xa7 does not depend on SA signaling and therefore avoids the inhibition of the SA pathway by high temperature (Wang et al., 2017). These
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