Molecular Microbiology Research, 2025, Vol.15, No.2, 82-92 http://microbescipublisher.com/index.php/mmr 83 In recent years, with the rapid development of plant molecular biology, genomics and molecular breeding technology, rice disease resistance breeding is gradually shifting from traditional empirical to precise design. Many disease resistance genes have been successfully cloned and their functions analyzed, such as Pita, Pi9, Pigm in rice blast, Xa21, Xa23, Xa5 in bacterial blight, and the genetic mechanisms and interaction patterns of these genes are gradually becoming clear (Yang et al., 2022; Younas et al., 2024). At the same time, advanced technologies such as molecular marker-assisted selection (MAS), genomic selection (GS) and CRISPR/Cas gene editing are gradually being applied to rice disease resistance breeding, accelerating the creation of new varieties (Molla et al., 2021). In particular, the widespread use of CRISPR/Cas technology has not only made it possible to accurately introduce disease-resistant genes, but also promoted the precise knockout of susceptible genes, providing a new way to improve rice disease resistance traits (Oliva et al., 2019; Huang et al., 2024). This study aims to systematically sort out the latest research progress and core characteristics of rice breeding for fungal and bacterial disease resistance, focusing on the pathogenic mechanism of rice blast and bacterial blight, the identification and regulation mechanism of disease resistance genes, and explore the role of signal pathways, transcription factors, miRNAs, etc. in disease resistance response, and introduce the practical application of molecular breeding technology in disease resistance trait improvement. The article will also demonstrate the creation path and field promotion effect of disease-resistant varieties through typical breeding cases, and look forward to the new trend of multi-disease joint resistance construction under the background of climate change. It is hoped that this review will provide theoretical support and technical reference for efficient and lasting rice disease resistance breeding in the future. 2 Research Progress on Fungal Diseases of Rice and Their Resistance 2.1 Research on the pathogenic mechanism and resistance inheritance of rice blast Rice blast is one of the most devastating diseases in global rice production, caused by the fungus Magnaporthe oryzae. The disease can occur throughout the growth period of rice, especially in the panicle neck blast stage from the booting stage to the heading stage, which is the most serious. In severe cases, it can lead to a significant reduction in yield or even a total crop failure (Younas et al., 2024). The pathogen invades the rice epidermis through appressorium, then forms infectious hyphae and infectious branches, and finally destroys cell tissues. Its pathogenic process is highly dependent on a series of secreted effector proteins, which can be recognized by disease resistance genes in the plant, thereby stimulating an immune response, namely the "effector-induced immunity" (ETI) mechanism (Koseoglou et al., 2022). For a long time, researchers have identified and cloned a large number of major effector resistance genes related to blast resistance in rice. As of 2024, more than 100 blast resistance loci have been reported, of which more than 30 genes have been successfully cloned (Pedrozo et al., 2025). Most of these genes encode typical NBS-LRR proteins, such as Pi9, Pita, Pib, Pik, Piz-t, etc., which can recognize specific pathogen effector proteins and activate downstream defense responses (Younas et al., 2024). Among them, Pi9 is a broad-spectrum resistance gene derived from wild rice, which can effectively resist multiple subspecies of rice blast fungi and has been widely used in multiple breeding programs (Sahu et al., 2022). In addition to major effect genes, some recessive genes also play an important role in rice blast. For example, the recessive disease resistance gene bsr-d1 encodes a C2H2-type zinc finger protein, which can upregulate peroxidase expression after mutation, increase the level of reactive oxygen in rice, and thus enhance resistance (Li et al., 2017). In addition, the application of high-throughput sequencing and whole-genome association analysis technology in recent years has enabled the precise positioning of multiple quantitative trait loci (QTLs) related to rice blast. Although this type of horizontal resistance is not as strong as the major effect gene, it is often more persistent and broad-spectrum, and is regarded as an important resource in blast-resistant breeding (Zhang et al., 2024). In the practice of resistance breeding, aggregating multiple disease-resistant genes into the same variety is an effective strategy to improve the resistance spectrum and extend the resistance period. For example, the Chinese
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