In recent years, we have witnessed transformative breakthroughs in plant disease resistance research, particularly in deciphering the intricate interplay between hosts and pathogens. Cutting-edge discoveries span pathogen recognition mechanisms, immune signaling cascades, and multi-layered interactions integrating plants, pathogens, vectors, and environmental variables. Notably, pioneering studies from domestic research institutions have driven progress across pathogen-sensing systems, secondary metabolite-mediated defense, immune module engineering in crops, and artificial intelligence (AI)-powered solutions for pathogen-resistant peptide design. The rapid development of CRISPR/ Cas9-based gene editing and AI technologies has further empowered researchers to engineer disease-resistant crop varieties with unprecedented precision. Such progress holds profound implications for ensuring national food security and advancing strategic priorities in disease-resistant crop breeding, marking a transformative era in agricultural biotechnology and sustainable agriculture.

Salicylic acid (SA) is a natural phenolic compound in plants that plays a crucial regulatory role in plant immune responses. Plants primarily synthesize SA through two pathways: the isochorismate synthase (ICS) pathway and the phenylalanine ammonia-lyase (PAL) pathway. The synthesized SA is perceived by receptors such as nonexpressor of pathogenesis-related genes 1 (NPR1), which subsequently activate immune responses. In Brassicaceae species like Arabidopsis thaliana, SA is mainly synthesized via the ICS pathway, whereas monocots and non-Brassicaceae dicots predominantly rely on the PAL pathway. For a long time, understanding of SA biosynthesis via the PAL pathway has been incomplete, hindering research on SA-mediated immunity in crops and significantly limiting progress in crop disease-resistant breeding. Recently, three research groups from China independently elucidated the PAL-mediated SA biosynthesis pathway in crops. Building on these breakthroughs, this review summarizes recent advances in the study of SA-mediated plant immune responses. We primarily focus on the biosynthetic pathways of SA within plants, the mechanisms by which SA is perceived and activates immune responses, and discuss current challenges and future directions in SA-mediated immunity research. We hope this review provides new insights and perspectives for both theoretical studies and practical applications in crop disease-resistant breeding.

The plant innate immune system serves as the primary defense against pathogen invasion, with well-established frameworks for receptor recognition and signal transduction mechanisms. This review highlights recent key breakthroughs in plant immunity research from Chinese institutions: (1) The discovery of novel mechanisms driving virulence evolution through asymmetric chromosome distribution in fungi and chromosome fusion in oomycetes; (2) Elucidation of the kinase MtLICK1/2-mediated molecular switch that precisely regulates the symbiosis-immunity trade-off via phosphorylation of MtLYK3 in legumes; (3) Identification of a “sensor-executor” paradigm where tandem kinases and NLR immune receptors cooperatively activate immunity in cereal crops; (4) Innovative strategies including co-transfer of sensor-helper NLR pairs to overcome taxonomic restrictions; and (5) Develop technology of autoactive NLR chimeras activated by pathogen protease cleavage for broad-spectrum resistance. These advances collectively deepen our understanding of plant-pathogen-environment interactions across three dimensions—pathogen adaptive evolution, sophisticated host immune regulation, and receptor engineering applications. Crucially, fundamental mechanistic insights have been successfully translated into crop genetic improvement practices. The integrated findings provide a robust theoretical foundation and actionable technological framework for designing novel crop varieties with durable, broad-spectrum disea- se resistance to address mounting agricultural biosecurity threats.

Pathogen infection is a serious threat to plant growth and development, causing severe crop yield reduction. The plant immune system, which is mainly composed of PTI (pattern-triggered immunity) and ETI (effector-triggered immunity), plays an essential role in resistance against pathogen infection. A large amount of research focused on resolving the key immune receptors/co-receptors, the components and regulation mechanisms of the PTI and ETI signaling pathways, and the biosynthesis and signaling pathways of the plant immune hormones salicylic acid and jasmonic acid. The major events during plant immune responses include pathogen recognition, the outburst of reactive oxygen species, Ca²⁺ influx, MAPK cascade signaling, and the induced expression of downstream defense genes. Recent studies have revealed that the expression of plant immune-related genes is not only regulated at the transcriptional level. The stability, translation efficiency, and translation products of their mRNAs are affected by a variety of post-transcriptional regulatory mechanisms, including alternative splicing, m⁶A modification, small RNAs, uORFs, and R-motifs. Here, we summarized the present understanding of the plant immune system and mainly introduced the latest studies of the post-transcriptional regulation of plant immunity. This review also covered some findings that showed how pathogen interferes with the host post-transcriptional regulatory machinery. Some post-transcriptional regulatory elements have been successfully applied in crops. This application provides new molecular tools for improving diseases resistance and contribution to food security, as well as useful components for molecular breeding.

Systemic acquired resistance (SAR) is a crucial defense mechanism in plants, which can significantly enhance the plant’s resistance to pathogenic microorganisms. SAR has systemic, persistent, and broad-spectrum characteristics, whose transcriptional regulation plays a central role in the process. Here, the research progress on transcriptional regulation of SAR from the synthesis of salicylic acid (SA), Pip/NHP, transcriptional regulation of NPR1, NPR3/NPR4 receptors and Pip/NHP mobile signals, as well as TGA, WRKY transcription factor family regulation was reviewed, providing a reference for a deeper understanding of plant immune regulatory networks, and systematic exploration of the mechanisms by which plants balanced growth and defense in complex environments.

Rice (Oryza sativa) is one of the most vital food crops globally, and its yield plays a crucial role in ensuring food security. However, various diseases affecting rice pose significant threats to this security. Among these, rice blast, bacterial blight, and sheath blight are the three predominant diseases impacting global rice production. Consequently, there is an urgent need to breed and cultivate rice varieties with broad-spectrum disease resistance. In recent years, substantial advancements have been made in understanding the regulatory mechanisms underlying disease resistance in rice. This paper reviews these mechanisms from multiple perspectives, including the plant’s intrinsic immune responses and the functional dynamics of resistance genes. Furthermore, it highlights pressing issues that require immediate attention to facilitate broad-spectrum disease-resistant breeding efforts for rice.

SUMOylation is a crucial post-translational modification in plants, playing a pivotal role in plant immune regulation by mediating substrate protein functions, the activation and transduction of immune signals, and hormonal signaling networks. This review systematically summarizes recent research advances in SUMOylation during plant-pathogen interactions, focusing on the enzymatic cascade mechanisms of the SUMOylation system, the involvement of SUMOylation in plant immune regulation, and the interference/activation of the SUMOylation system by pathogen effector proteins. We highlight the SUMOylation-mediated regulatory networks of plant immunity and provide a reference for developing novel disease resistance strategies in crops based on SUMO modification.

Rice bacterial leaf streak (BLS), caused by Xanthomonas oryzae pv. oryzicola (Xoc), is a significant quarantine disease. The pathogen exhibits both high genetic diversity and strong transmission capabilities. Driven by agricultural intensification and global warming, BLS has been progressively expanding across major indica rice-producing regions in southern China. This review systematically summarizes recent advances in Xoc-rice interaction mechanisms: (1) Pathogen perspective: elucidating pathogenic mechanisms of virulence factors (including T2SS, T3SS, and extracellular polysaccharides (EPS)) and pathovar differentiation patterns; (2) Host perspective: clarifying advances in PTI/ETI-mediated immunity signaling pathways, resistance (R) gene cloning, and susceptibility (S) gene editing; and (3) Future directions: proposing multi-omics approaches to decode Xoc pathogenicity networks, leveraging pan-genomics for large-scale mining of durable and broad-spectrum R genes, and constructing synergistic systems integrating S gene editing with immune activation to establish systematic solutions for sustainable BLS management.

The plant cell wall, which is composed of cellulose, hemicellulose, pectin and lignin, is a dynamically changing network structure, that not only plays the role of a key line of defense in the process of plant resistance to external pressure and adaptation to environmental changes, but also plays the role of an information hub in the process of signal transmission. When the cell wall is damaged, cells sense cell wall changes and initiate early immune responses, such as hormonal changes, alterations in wall composition and modifications, and the production of disease-resistant secondary metabolites. Although the importance of the cell wall in plant immunity is widely recognized, the specific molecular mechanisms by which cell wall damage triggers immune responses remain poorly understood. The application of in situ unlabeled imaging techniques in plant cells is gradually increasing and has become an important tool for studying cell wall structure and function. This paper describes the interaction mechanism between the plant cell wall and the immune response to provide a scientific basis for a deeper understanding of plant life activities and improve crop disease resistance, and describes in situ non-labeled imaging of the cell wall to provide more technological options for advancing the study of the cell wall in the immune response.

Unraveling the mechanisms of plant disease resistance and immunity is crucial for breeding disease-resistant crops and safeguarding national food security. Photoreceptors, which are central for perceiving environmental signals, not only fine-tune plant growth and development, but also serve as key signaling hubs in plant-pathogen interactions. Studies have demonstrated that photoreceptor interact directly or indirectly with the COP1/SPA complex, HY5, PIFs, and other light-signaling components. By regulating the spatiotemporal expression of resistance-related defense genes and controlling the synthesis and response networks of defense-related hormones, photoreceptors precisely integrate light signals with pattern-triggered immunity (PTI) and effector-triggered immunity (ETI), thereby balancing plant growth and immunity. In recent years, research into the interaction between light signaling and plant immune systems has become a hot topic in the field of plant biology. Elucidating these underlying mechanisms offers new directions for breeding disease-resistant crops. This paper focuses on the molecular mechanisms of plant disease resistance regulated by photoreceptors, particularly the immune activation mechanisms mediated by photoreceptors and their spatiotemporal integration with immune-related hormone signals. Additionally, it delves into the potential application of optogenetic technology in studying this interaction. The aim is to provide new theoretical and technical avenues for future molecular breeding of disease-resistant crops, which will be based on photoreceptor modification and signal transduction pathways.

INTRODUCTION: The genetic diversity of common wheat (Triticum aestivum) has decreased sharply due to the domestication and modern breeding operations, making it more vulnerable to the threats from pests and pathogens. Leaf rust, caused by the fungal pathogen Puccinia triticina (Pt), is a devastating disease in wheat. Over 80 leaf rust resistance (Lr) genes have been identified, with nearly half originating from wheat wild relatives. However, the rapid evolution of Pt has rendered many Lr genes ineffective against prevalent Pt races. Consequently, identifying novel sources of resistance in wild relatives of common wheat remains an urgent priority for sustainable wheat breeding.

RATIONALE: As one of the most widely used relatives in the genetic improvement of wheat, decaploid Thinopyrum ponticum shows excellent resistance to multiple diseases including leaf rust. By distant hybridization and chromosome engineering, we created a wheat-Th. ponticum line WTS135. We evaluated its disease resistance with Pt race THTT, developed Th. ponticum specific markers by specific-locus amplified fragment sequencing technology and assessed its agronomic traits by phenotypic investigation. Genomic in situ hybridization (GISH)-fluorescence in situ hybridization analysis (FISH) and liquid chip analysis have been used to identify its chromosome composition.

RESULTS: WTS135 is immune to the Pt race THTT. Pedigree analysis showed that this resistance originated from the exogenous chromosome of Th. ponticum. GISH-FISH analysis revealed that the wheat chromosomes 7D were replaced by the Th. ponticum-derived chromosomes. Liquid chip analysis showed that the alien chromosomes belonged to the homoeologous group 7, and the density and abundance of the signals in the peri-centromeric region were significantly lower, which was consistent with the GISH results. Therefore, it is indicated that WTS135 is a 7St (7D) disomic substitution line. After detected by the molecular markers related to known Lr genes on wheat 7D chromosome, it is speculated that WTS135 probably carries a novel resistance gene that is different from genes Lr19 and Lr29. Ten primers specific to Th. ponticum were developed to rapidly trace the exogenous chromatin in WTS135. Phenotypic investigation showed that the yield of WTS135 was not significantly different from that of the recurrent parent Jimai 22, suggesting that this line can be useful for improving disease resistance in wheat.

CONCLUSION: Introducing resistance genes from wild relatives into wheat through distant hybridization can broaden the genetic base of wheat and provide new sources for breeding disease-resistant varieties. We developed a common wheat-Th. ponticum 7St (7D) substitution line, which possibly has a novel alien resistance gene and could be used in the breeding for enhancing wheat disease resistance.

Chromosome composition and leaf rust resistance evaluation of WTS135. (A) GISH analysis using Thinopyrum ponticum gDNA as a probe and Chinese Spring gDNA as a block; (B) Mc-FISH analysis using combined oligo probes; (C) The liquid chip analysis of WTS135; (D) Evaluation for leaf rust resistance in WTS135 and its parents (1: WTS135; 2: Xiaoyan 81; 3: Jimai 22, 4: Zhongnong 28, 5: Th. ponticum). The white arrows indicate exogenous chromosomes, purple frames indicate chromosome additions or deletions.

INTRODUCTION: Verticillium wilt (VW), caused by Verticillium dahliae, severely reduces cotton yield and fiber quality. Previous transcriptomic analysis in V. dahliae-inoculated Arabidopsis thaliana identified the pathogen-induced DIR1-like gene AT3G53980.2. In cotton, we discovered a homologous gene, GhDIR1 (Gh_A09G180700.1), encoding a lipid transfer protein. This study investigates its role in cotton resistance to V. dahliae.

RATIONALE: We characterized GhDIR1’s molecular features, expression patterns under pathogen stress, and functional impact using bioinformatics, subcellular localization, qRT-PCR, and virus-induced gene silencing (VIGS) analyses. Transcriptomic analysis of wild-type and GhDIR1-silenced plants were conducted to unravel downstream regulatory networks, focusing on metabolic pathways linked to plant immunity.

RESULTS: The results showed that GhDIR1 contains a 351 bp ORF encoding 116 amino acids. Subcellular localization confirmed its presence on the cell membrane. qRT-PCR showed rapid induction of GhDIR1 by V. dahliae. Silencing GhDIR1 increased cotton susceptibility to the pathogen. Transcriptomic data revealed that differentially expressed genes in silenced plants were enriched in flavonoid biosynthesis, sesquiterpene/triterpene biosynthesis, and α-linolenic acid metabolism. Key genes (GhCHS, GhDFR, GhCAD, GhSEQ, GhLOX, and GhAOC) in these pathways were downregulated, suggesting impaired synthesis of protective metabolites.

CONCLUSION: It is speculated that GhDIR1 positively regulates cotton resistance to VW by modulating flavonoid and terpenoid biosynthesis and jasmonic acid-related signaling. Its silencing disrupts critical defense pathways, highlighting its role in coordinating immune responses. These findings propose GhDIR1 as a potential target for enhancing disease resistance in cotton.

The induced expression pattern of GhDIR1 and related genes after inoculation with Verticillium dahliae.

INTRODUCTION: Bacterial blight is one of the three major diseases that threaten global rice production, seriously damaging the yield and quality of rice. The utilization of resistance genes is one of the most effective ways to control bacterial blight.

RATIONALE: To cultivate rice varieties with both resistance to bacterial blight and high-yield characteristics, stable and efficient resistance genes need to be identified and used. To identify quantitative trait locus (QTL) related to bacterial blight resistance in rice, this study used the indica rice HZ, the japonica rice Nekken2 and their 120 recombinant inbred lines (RILs) as experimental materials. Four different races of bacterial blight pathogens were inoculated at the tillering stage of rice and the resistance phenotypes were evaluated.

RESULTS: Based on the high-density genetic map constructed previously, we identified 19 QTLs for resistance to rice bacterial blight, with the maximum limit of detection (LOD) value being 5.49. Candidate genes within the detected QTL intervals were screened based on their expression levels analyzed by qRT-PCR. LOC_Os04g01310 and LOC_ Os04g01320, which are related to the regulatory pathway of STK receptor protein, showed significant upregulated expression after inoculation treatment. Meanwhile, the expression levels of the MYB transcription factor family gene LOC_Os05g10690 and the gene LOC_Os01g12320 related to GDSL-like lipase/acylhydrolase showed an extremely significant increase after inoculation treatment. The expression levels of the candidate genes LOC_Os02g13270 (Mpv17/PMP22 family domain containing protein), LOC_Os02g13410 (leucine rich repeat family protein), LOC_ Os02g13420 (leucine rich repeat receptor protein kinase EXS precursor), LOC_Os02g13430 (receptor-like protein kinase 5 precursor) and LOC_Os01g12130 (enodulin MtN3 family protein) were significantly different between the two parents and were induced after inoculation with the bacterial blight pathogen.

CONCLUSION: By QTL mapping and gene expression analysis, we identified several candidate genes related to rice bacterial blight resistance. These results provide clues for further fine mapping and cloning of new bacterial blight resistance genes for future breeding of rice varieties with strong resistance to bacterial blight.

QTL mapping of resistance to bacterial blight in recombinant inbred lines of rice. QTLs can be used to reveal the structure of complex quantitative traits and identify candidate genes. Based on a high-density genetic map, a total of 19 QTLs were co-located and multiple candidate genes were screened out. To further locate and clone the related genes and lay a theoretical foundation for breeding new high-yield and disease-resistant rice varieties.

INTRODUCTION: The phytohormone salicylic acid (SA) plays multiple important roles in plants, such as disease resistance, seed germination, and leaf senescence. Among these, the role of SA in plant disease resistance is the most studied. Since SA promotes disease resistance at the cost of plant growth, plants need to dynamically regulate the content of SA to balance disease resistance and growth. Therefore, fast and accurate measurement of SA content is a critical basis for plant immunity research.

RATIONALE: High-performance liquid chromatography (HPLC)-fluorescence detector is the most popular method for the quantitative measurement of SA. In order to improve the efficiency and sensitivity of current methods, this study optimized the composition, ion concentration, and pH of the mobile phase, as well as the detection wavelength and detection procedure.

RESULTS: The baseline of the chromatogram was more stable when using acetonitrile instead of methanol in the mobile phase. When the pH of the mobile phase was 5.2, the retention time of SA was the shortest, without interference peak near the SA peak, which was preferred for minimizing the detection time. The higher concentration of sodium acetate (100 mmol∙L^-1) in the mobile phase was better than that of lower concentration (20-50 mmol∙L^-1). Wavelength scanning revealed that the optimal excitation wavelength was 300 nm and the optimal emission wavelength was 405 nm, under which the highest sensitivity for SA detection was obtained. At a flow rate of 2 mL∙min^-1, it took 3.5 min for elution, 3.5 min for column wash, and 3 min for column balance, shortening the measurement time per sample from 50 min to 10 min.

CONCLUSION: These optimizations greatly improved the sensitivity, stability, and efficiency of the SA measurement using HPLC, which will contribute to the plant immunity research.

Optimization of salicylic acid (SA) measurement. (A) SA detection procedure; (B) Chromatogram using the optimized condition. The samples are total SA in Arabidopsis without Psm ES4326 infection. EU: Emission units. The peak labeled in red indicates SA.