Xylella fastidiosa is a plant-pathogenic bacterium that causes severe diseases in economically important crops, such as citrus and grapevine, thereby posing a significant threat to global agriculture. Although X. fastidiosa has not yet been reported in Korea, the increase in international trade and its presence in neighboring countries highlight the necessity of continued surveillance. The objective of this study was to verify the absence of X. fastidiosa in Korea and to establish a reliable diagnostic framework through a nationwide survey conducted in 2024 and 2025. The sampling design was generated using the RiBESS+ statistical model to ensure the reliability of the survey results. Host plants, including grapevines (Vitis vinifera), mandarin oranges (Citrus unshiu), and cherry blossoms (Prunus yedoensis), were selected and sampled from urban and agricultural areas throughout the country for a nationwide survey. Genomic DNA was extracted from plant petioles and analyzed using real-time PCR with an optimized primer set (XF16S-F/R). Over a period of two years, a total of 2,314 samples were collected, exceeding the required sample size of 843 per year. X. fastidiosa was not detected in any of the collected and tested samples. These results confirm the absence of X. fastidiosa in Korea throughout the study period with high statistical confidence. This study provides evidence confirming the absence of X. fastidiosa in Korea and proposes a standardized methodology for future surveillance and early detection of other invasive prohibited quarantine pests.
Fusarium asiaticum and Fusarium graminearum, belonging to the Fusarium sambucinum species complex (FSAMSC), are primary causal agents of Fusarium head blight (FHB) and associated mycotoxin contamination in cereal crops worldwide. In this study, we performed a nationwide survey of Fusarium populations in rice, a staple crop in Korea, and examined the distribution of trichothecene genotypes and the mycological characteristics of dominant species. A total of 1,008 Fusarium isolates were obtained from rice (375) and plants surrounding rice paddy fields, including maize (133) and gramineous weeds (500). FSAMSC members accounted for the majority (59-70%) of Fusarium isolates from the three plants, with F. asiaticum predominating in both rice (57%) and weeds (44%), whereas F. graminearum was dominant in maize (41%). Trichothecene genotype analysis revealed that the nivalenol (NIV) type of F. asiaticum predominated in rice (82%) and weeds (70%), whereas the 15-acetyldeoxynivalenol (15ADON) type of F. graminearum was more common in maize (83%). A comparison of the mycological traits of two dominant species highlighted that F. asiaticum NIV type strains exhibited significantly higher pathogenicity in rice than F. graminearum 15ADON type strains (P = 0.01), despite lower growth and reproductive capacity (P < 0.05). By integrating this largescale distribution survey with mycological analyses, we showed that F. asiaticum is a major contributor to FHB and trichothecene risks in the rice cultivation system in Korea.
Fungi are major phytopathogens that have a strong impact on agricultural productivity. Recently, biological control has gained attention for managing plant pathogenic fungi due to its eco-friendly characteristics. Hence, using biological agents to replace chemical fungicides is a viable alternative approach in sustainable agriculture systems. In this study, we demonstrated the potentiality of Streptomyces sp. VNUA24 as a promising biocontrol agent. The strain strongly inhibited mycelial growth of several common pathogenic fungi. Its culture filtrate also altered fungal morphology, restricted hyphal elongation, inhibited spore germination, and suppressed fungal virulence. Biochemical assays and genomic analysis revealed the productions and encoding genes for several hydrolytic enzymes. The antiSMASH analysis identified 38 biosynthetic gene clusters in the genome. Interestingly, many of these exhibited strong homologies to clusters responsible for producing established antifungal metabolites such as ε-poly-L-lysine, concanamycin A, informatipeptin, and humidimycin. These findings highlight the strong antifungal potential of Streptomyces sp. VNUA24 and suggest that it is a promising candidate for developing microbial control agents in sustainable fungal disease management.
Angular leaf spot, caused by the phytopathogenic bacterium Xanthomonas fragariae, results in considerable yield losses in strawberry production. This pathogen is designated as a quarantine pest in several countries, including South Korea. Therefore, early identification of this pathogen in young plants is essential for preventing disease spread and ensuring rapid eradication. However, intraspecific genetic variation among isolates from different geographic origins imposes challenges for the accurate diagnosis of X. fragariae. In this study, we developed a novel gene marker and primer set (XF-212F/R) through comparative genomic analysis of X. fragariae strains and related bacterial species for pathogenspecific detection. As a result, the XF-212F/R primer set amplified only X. fragariae strains without cross-reactivity to other Xanthomonas spp. or related bacteria. The detection limits of the SYBR Green real-time PCR assay were 1.41 × 10² plasmid copies/μL, 500 fg of genomic DNA, and 1.52 × 10³ CFU/mL of bacterial cells. The assay also accurately detected the pathogen from cells directly extracted from infected strawberry leaves, enabling rapid detection without the need for DNA extraction. This diagnostic method showed improved coverage for X. fragariae strains and is suitable for early detection and disease surveillance in strawberry plants.
The Global Plant Health Assessment is a collaborative project involving approximately one hundred scientists across the world, addressing the global state of plant health as a common good. The project is unusual in that it relies entirely on voluntary contributions from scientists, operates without dedicated funding, and incorporates internal collaboration mechanisms for peer review and publication. Plant Health Reports have been developed by teams of scientists for more than 30 cases, each focusing on a purposely selected keystone plant species representing plant systems in multiple world ecoregions. These plant systems encompass forests, field crops, perennial crops, household and periurban systems, as well as urban forests, in both the Global North and the Global South. Despite this necessarily fragmented information, an overall view however emerges on the current state and recent evolution of world plant health, as well as on the consequences of declining plant health on three categories of ecosystem services generated by healthy plants: provisioning, regulating, and cultural-spiritual. Additional reports are being developed to improve this view, along with new developments where the future of plant health and its consequences will be addressed. As a project structure and organisational model, the Global Plant Health Assessment could serve as a template for future collective scientific efforts addressing major questions about global common goods.
Volatile organic compounds (VOCs) are valuable compounds in diverse microbial interactions with certain biotic stimuli, yet pivotal roles of any VOCs derived by the rice blast fungus, Magnaporthe oryzae, in intra- and interspecies communications have been poorly understood. Therefore, in this study, we investigated that how certain VOCs by M. oryzae affect the fungal growth of the same species and other species. Using a partitioned I-plate assays, the result showed that pre-inoculated fungal colony (sender) significantly suppressed the late arriving colony (receiver) in a time- and mediadependent manner, suggesting that VOCs may function as self-inhibition agents in regulation of fungal growth. A total of eleven compounds were identified by the gas chromatography-mass spectrometry, among which four VOCs (1-hexanol, 2-ethylhexanoyl chloride, 1-octen- 3-ol, and 3-octanol) exhibited strong self-inhibition effects. Further analysis revealed that the self-inhibition mediated by M. oryzae VOCs was enhanced under light conditions compared with darkness. Genetic approaches revealed that deletion of the MoCPKA and MoPMK1 genes reduced the self-inhibitory effects, suggesting that both genes are required for growth inhibition and that VOCs play a pivotal role in regulating turgor pressure generation and appressorium formation. In addition to self-inhibition effects, M. oryzae-mediated VOCs contributed to the interspecific antagonistic interactions with other fungal species (Aspergillus nidulans, Fusarium oxysporum f.sp. conglutinans, and Sclerotinia sclerotioum). Our data clearly demonstrated that VOCs produced by the M. oryzae under light conditions are the key factors in enhancing growth inhibition both within a species (intraspecific) and among different species (interspecific).
Watermelon (Citrullus lanatus Thunb.) and melon (Cucumis melo L.) are globally important horticultural crops, cultivated widely for their economic and dietary value. However, their productivity is increasingly threatened by Fusarium wilt, which causes substantial yield losses. The genus Fusarium comprises over 400 phylogenetically distinct species, classified into multiple species complexes (SCs). Many of these species are soilborne and resilient in agroecosystems, complicating accurate identification and disease management. While Fusarium oxysporum formae speciales–f. sp. niveum (FON) and f. sp. melonis (FOM)–have long been considered the main causal agents of Fusarium wilt in watermelon and melon, an increasing number of regional studies suggest that diverse Fusarium spp. may also be involved. In this study, we examined the diversity and pathogenicity of Fusarium spp. causing wilt in watermelon and melon across key cultivation regions in Korea. Thirty-three Fusarium isolates were initially identified using internal transcribed spacer (ITS) sequencing and further characterized through multilocus phylogenetic analysis of the translation elongation factor 1-alpha (EF-1α) and the RNA polymerase second largest subunit (RPB2) genes. The isolates were classified into five distinct SCs: F. oxysporum (FOSC), F. nisikadoi (FNSC), F. fujikuroi (FFSC), F. incarnatum–equiseti (FIESC), and F. solani (FSSC). Morphological and microscopic features were examined to support SC-level classification. Pathogenicity assays confirmed that representative isolates from each SC induced wilt symptoms in both watermelon and melon. These results broaden the understanding of Fusarium diversity in cucurbits and underscore the needs for phylogenetically informed diagnostics and disease management strategies.
Pepper anthracnose, a devastating and economically important disease in Korea, is caused by diverse Colletotrichum species that differ significantly in their pathogenicity and environmental adaptation. In a three-year study from 2022 to 2024, pathogens were isolated and species characteristics were investigated. Using multilocus phylogenetic analysis and species-specific PCR, seven species were identified: C. scovillei, C. nymphaeae, and C. fioriniae in the C. acutatum species complex; C. fructicola, C. aenigma, and C. gloeosporioides in the C. gloeosporioides species complex; and C. truncatum. C. scovillei remained dominant, but species diversity increased in 2024, with non-dominant species such as C. fructicola and C. truncatum increasing in specific regions. Temperature-dependent assays revealed distinct ecological niches, showing that while C. scovillei prefers a moderate 25°C, high temperature-adapted species like C. fructicola and C. truncatum exhibit enhanced growth and pathogenicity at 30°C. Fungicide sensitivity tests showed that tebuconazole and fluazinam remained effective against all species of Colletotrichum, whereas pyraclostrobin (QoI) resistance was widespread. The mycelial growth inhibition of C. scovillei by pyraclostrobin ranged from 29.5% to 43.3% during 2022–2024, indicating reduced sensitivity. All C. truncatum isolates were resistant, consistently associated with the G143A mutation in the cytb gene. These findings indicate that climate warming and fungicide selection pressure are driving shifts toward more resilient populations, highlighting the need for climate-adaptive disease management through monitoring and fungicide rotation.
Numerous fungicides are essential for controlling phytopathogens, enabling modern industrial agriculture to maximize productivity and profitability. However, the extensive use of widely employed fungicides, such as tebuconazole and carbendazim, has led to reduced efficacy due to the emergence of resistant plant-pathogenic fungi. Accordingly, in this study, we synthesized a 2‑pyrone chemotype bearing a ynone substituent, designated as ynone 6 and evaluated its potential as an antifungal scaffold. This representative lead compound exhibited broad-spectrum antifungal activity against five major phytopathogens, including Fusarium graminearum and Botrytis cinerea. Ynone 6 demonstrated potent in planta control efficacy across various host tissues, including wheat spikes, fruits, and leaves, with inhibitory effects comparable to those of tebuconazole. Sensitivity screening using six knockout mutants targeting well-established antifungal pathways revealed that the sensitivity profiles of the mutants differed significantly between conidial germination and hyphal growth, suggesting that the mode of action of ynone 6 is stage-dependent and may involve multiple targets. Collectively, the potent in vitro activity of ynone 6 and its consistent in planta efficacy across multiple host-pathogen systems highlight the ynone-tethered 2-pyrone scaffold as a promising lead scaffold for the development of effective antifungal agents.
Chili pepper (Capsicum annuum) is a major horticultural commodity in Indonesia whose productivity is constrained by viral diseases, particularly pepper yellow leaf curl virus (PepYLCV). This study investigated the spatial distribution, symptomatology, incidence, severity, and genetic diversity of PepYLCV in seven primary chili‑producing districts of Lampung Province, namely North, Central, South, and West Lampung, Pesawaran, Pringsewu, and Tanggamus. Field surveys combined with molecular diagnostics demonstrated widespread PepYLCV infection, with disease incidence reaching 91% and 85% and disease severity 79% and 77% in Tanggamus and West Lampung, respectively. Symptom expression, including leaf curling, yellow mosaic, leaf size reduction, and stunting, varied among agroecosystems. Infection by PepYLCV was confirmed through PCR using begomovirus‑specific primers, and partial nucleotide sequences of the replication‑associated (AC1/AC2) and coat protein (AV1) genes showed 86-94% identity with PepYLCV isolates in GenBank, indicating close relatedness within the Indonesian PepYLCV complex. Phylogenetic analyses grouped all Lampung isolates in a well‑supported clade (bootstrap 99-100%) distinct from foreign begomoviruses, and the pronounced genetic homogeneity is consistent with efficient regional spread mediated by the whitefly Bemisia tabaci. Collectively, these findings demonstrate that PepYLCV constitutes a serious constraint to chili production in Lampung and poses a risk of further dissemination to other production centers, underscoring the need for integrated disease management through vector suppression, deployment of PepYLCV‑resistant cultivars, and strategic development of mild strain cross‑protection.
While cinnamon essential oil (CEO) is increasingly recognized as a potent natural antimicrobial, its precise multi-target mechanisms against the destructive agricultural pathogen Xanthomonas euvesicatoria remain unclear. This study comprehensively elucidated the physiological, biochemical, and transcriptomic responses of X. euvesicatoria 173 to CEO-induced stress. We investigated its antibacterial efficacy and specific modes of action using microdilution assays, scanning electron microscopy, biochemical viability tracking, and RNAseq. CEO exhibited robust dose-dependent antibacterial activity, with a minimum inhibitory concentration of 400 mg/L and a half-maximal effective concentration (EC50) of 164 mg/L. Analyses revealed that CEO severely compromised cell membrane integrity, leading to a rapid 100-fold increased hypersensitivity to osmotic stress and significant suppression of biofilm formation. Furthermore, sub-lethal CEO exposure induced a severe energy crisis by disrupting membrane-dependent ATP synthesis—measured as a significant reduction in F1F0-ATPase activity—and caused abnormal cellular elongation, indicating cell division arrest. These distinct phenotypes were supported by comparative transcriptomics at the sub-lethal EC50 dose, which revealed 209 highly significant differentially expressed genes (|log2FC| > 3.321). CEO massively downregulated genes associated with the electron transport chain and core energy metabolism (nuo, ndh, cyd, and cyo operons), the ftsZ divisome network, and biofilm-associated type IV pilus and chemotaxis. Conversely, oxidative stress defense genes (kat and ahpD) were upregulated. In conclusion, CEO exerts its bactericidal activity through a synergistic, multi-target action—simultaneously dismantling membrane energetics, inducing severe metabolic suppression, and repressing vital developmental architectures. These findings highlight the significant potential of CEO as a sustainable, resistance-breaking biopesticide for crop protection.
Metatranscriptome analysis and reverse transcription polymerase chain reaction (RT-PCR) were performed on 75 Narcissus to investigate viral disease, leading to the detection of Japanese iris necrotic ring virus (JINRV, Betacarmovirus iridis). RT-PCR detected JINRV in 22 of 75 samples, all collected from Shinan, with a regional infection rate of 55.0% (22/40). The complete genome sequence of JINRV isolate SA36 was 4,060 nucleotides long and contained five open reading frames. Sequence analysis revealed that Narcissus-derived JINRV isolates shared 98.0–100% coat protein amino acid identity among themselves, and 71.9–91.5% with previously reported Iris-derived isolates. Sap inoculations showed that JINRV was mechanically transmitted to Cucurbita pepo. JINRV was exclusively detected in plants co-infected with other viruses, reflecting the complex mixed infection status prevalent in Narcissus. This study is expected to contribute to the quarantine of Narcissus bulbs and to the production of high-quality Narcissus in Korea.
Fungicides have been a reliable and efficient option for controlling various fungal plant pathogens, and unmanned aerial vehicle (UAV) systems have improved the cost and labor efficiency of fungicide application. However, UAV-mediated disease control systems still have the potential to improve application efficiency and control efficacy. In this study, we evaluated the in vitro sensitivity of garlic leaf blight pathogens (Stemphylium spp.) to different fungicides and performed pot and field assays using mobile spraying equipment (MSE) and an agricultural UAV to select the appropriate fungicide and concentration for controlling garlic leaf blight. Recently isolated Stemphylium spp. showed reduced sensitivity to kresoxim-methyl and various sensitivity to boscalid, ipflufenoquin, mancozeb, and metconazole. In the pot assay using the MSE, metconazole and ipflufenoquin were the most effective among the five ficacy, respectively. Further concentration experiments showed high control efficacy of metconazole and ipflufenoquin at the labeled concentration, indicating that the MSE successfully simulated UAV spraying conditions. Under field conditions, UAV-mediated fungicide application showed higher control efficacy (45.54%) and a lower mean AUDPC value for metconazole at the labeled concentration. Consistent fungicide application was verified by calculating the surface coverage area of water-sensitive papers after application by the MSE or UAV. This study provides a basis for developing a more efficient and effective UAV-based fungicide application system.
Anthracnose disease caused by Colletotrichum species is one of the most economically important, frequently leading to substantial yield and quality losses. This study investigated the biocontrol potential of two rhizosphere-associated bacteria, Paenibacillus polymyxa GYUN-2285 and Pseudomonas protegens GYUN-2679 isolated from soil. GYUN-2285 and GYUN-2679 were evaluated separately, and the two strains were subsequently co-applied to examine whether their combined treatment improved pathogen suppression relative to individual applications. Dual culture assays showed that both strains inhibited a broad range of plant pathogenic fungi, including several Colletotrichum species. The combined application of the two strains significantly promoted plant growth, enhancing seedling vigor and development. In planta experiments on pepper fruits revealed that individual applications GYUN-2285 and GYUN-2679 significantly reduced disease serverity. Notably, the combined treatment showed greater numerical suppression than the individual treatments under the tested conditions. This improved performance may be associated with the complementary functional traits of the two bacteria, which may broaden their antagonistic activity against pathogens. These findings suggest that the integration of GYUN-2285 and GYUN-2679 into biocontrol strategies offers a promising, sustainable, and eco-friendly alternative for managing anthracnose in peppers.
Auxin production by plant-associated bacteria is increasingly recognized as a determinant of host colonization, yet its integration into virulence networks remains incompletely understood. Nitrilase-dependent auxin (IAA) biosynthesis contributes to virulence in Xanthomonas oryzae pv. oryzicola (Xoc), but whether this mechanism operates in X. oryzae pv. oryzae (Xoo) has remained unclear. Here, we identify two conserved nitrilases, NIT24 and NIT29, in the Xoo strain PXO99A and examine their contributions to IAA production and virulence. Deletion of either gene reduces IAA accumulation, and under the tested conditions ΔNIT29 tended to show a stronger reduction, together with attenuated virulence characterized by shorter lesions and decreased in planta bacterial growth. Hormone profiling indicates a shift from auxin toward salicylic acid (SA)-associated responses in nitrilase-deficient infections, accompanied by reduced expression of auxin-responsive genes and enhanced activation of SA-related defense markers. In addition, nitrilase mutants display defects in biofilm formation, cellulase activity, and chemotactic motility, and exhibit altered expression of type III secretion system regulators, transcription activator-like effectors, and diffusible signal factor quorum-sensing components. Together, these findings support that nitrilase-mediated auxin biosynthesis contributes to multiple aspects of Xoo virulence and bacterial fitness and is associated with modulation of host hormone balance, suggesting a conserved role for auxin in X. oryzae pathosystems and its involvement in the interplay between bacterial physiology and host immune responses.
Soybean (Glycine max) is an important legume crop worldwide. An emerging leaf spot was observed in soybean plants with obvious black necrotic spot symptoms during the disease survey in Changping District, Beijing, China. To confirm the causal agent, the pathogen was isolated from the diseased leaves. Three isolates were obtained and showed a morphology extremely similar to Paramyrothecium vignicola. The isolates were identified by morphological and molecular characteristics. Phylogenetic analyses were performed using multiple gene regions (ITS, cmdA, rpb2, and tub2). The result indicated that the three isolates showed a high similarity (100%) with the known P. vignicola strains. Pathogenicity and host range tests of the isolates were performed on soybean and other legume crops. Three isolates were strongly pathogenic to soybean, hyacinth bean, common bean, faba bean, pea, mung bean, and lentil; moderate pathogenicity on adzuki bean; mild pathogenicity on cowpea and peanut. To screen resistant germplasms for disease control, the screening experiment of inoculum concentration of P. vignicola were performed. The result showed the most suitable concentration of P. vignicola isolate is 1 × 105 spores/mL for evaluation of germplasms resistance. Paramyrothecium species have been frequently identified to cause leaf spot and blight disease on a wide range of vegetables, ornamental plants, and economic crops. To our knowledge, this is the first report of P. vignicolaa inducing leaf spot on soybean worldwide. This study indicates P. vignicola might pose a potential risk to legume crops in the future.
Topically applied double-stranded RNA (dsRNA) can trigger antiviral RNA interference in plants, but naked dsRNA is unstable and poorly taken up after foliar application. Here, we developed an eco-friendly chitosan– tripolyphosphate (CS-TPP) nanocarrier to enhance dsRNA delivery using turnip crinkle virus (TCV) as a model and tested it in Arabidopsis thaliana. A dsRNA targeting the TCV-coat protein (CP) gene was produced in Escherichia coli, and complexation with CS-TPP was induced by ionic gelation. Complete complexation occurred at a 1:1 CS-TPP:dsRNA ratio, producing cationic nanoparticles that protected dsRNA from RNase digestion and maintained its integrity during incubation at 37°C. Using Cy3 fluorescence imaging, we observed stronger epidermis-associated fluorescence in plants treated with the CS-TPP@dsRNA complex than in those treated with naked dsRNA, and RT-qPCR confirmed higher CP-target RNA fragment accumulation in planta. Small RNA sequencing revealed increased levels of TCV-derived, 21–24 nt siRNA molecules targeting the CP region, suggesting the applied dsRNA was processed in planta. Importantly, a CS–TPP@ TCV-dsRNA foliar spray application reduced systemic CP RNA levels at 7 and 14 days post-treatment and alleviated disease symptoms more effectively than naked dsRNA. These results demonstrate that CS–TPP nanocomplexation improves dsRNA stability and delivery, enabling improved and more durable antiviral protection.
The pathogenic fungus Tilletia foetida causes common bunt in wheat, replacing grains with black spores and consequently reducing yield and quality. To assess the impact of crop rotation on soil health and pathogen dynamics, we investigated the effects of Medicago sativa L. (alfalfa) rotation on common bunt-infected wheat fields, compared with Avena sativa L. (oat) rotation. Soil eukaryotic communities were analyzed using Illumina MiSeq 18S rDNA sequencing. Additionally, soil physicochemical properties, enzyme activities (urease, phosphatase, peroxidase, and sucrase), and the abundance of T. foetida DNA were measured. Results showed that alfalfa/wheat rotation increased soil eukaryotic communities in the soil rhizosphere. The most abundant phyla were Mucoromycota, Mollusca, and Basidiomycota. While total phosphorus (TP), total nitrogen (TN), and pH remained largely unchanged, NO3--N, NH4+-N, and available potassium (AK) levels varied, correlating with changes in enzyme activities and soil eukaryotic communities composition. Compared with diseased wheat monoculture, alfalfa rotation was associated with significantly lower soil T. foetida DNA abundance and enhanced soil enzyme activity. These findings indicate that alfalfa rotation substantially improves the soil eukaryotic community, and plays a crucial role in reducing the T. foetida DNA abundance in soil.
Bacterial pathogens employ a large array of type III-secreted effectors to manipulate host cell immunity and metabolism. Ralstonia solanacearum species complex, the causal agent of bacterial wilt disease in numerous plant hosts, deploy a conserved subset of RipG effectors containing leucine-rich repeats and an F-box motif that collectively contribute to virulence and host specificity. RipG effectors are proposed to hijack the eukaryotic ubiquitin-proteasome machinery through the recruitment of substrates to host Skp1-cullin-F-box ubiquitin-ligase complexes via RipG F-box/host Skp1 adaptor interactions. However, only few host proteins have been reported to interact with RipG effectors. Here, using a surrogate type III delivery and a heterologous expression systems, we show that RipG6 can suppress plant pattern-triggered immunity in an F-box-dependent manner. We further identified a tomato receptor-like cytoplasmic kinase (SlRLCK-VIII-6) as an interactor of RipG6 in yeast and plant cells. SlRLCK-VIII-6 stability was reduced when co-expressed with RipG6 but not with the RipG6 variant lacking the F-box motif. Lastly, we provide evidence that Nicotiana benthamiana and Arabidopsis thaliana homologs of SlRLCK-VIII-6 can act as positive regulators of plant immune signaling. Together, our work supports a model where RipG6 destabilizes RLCK-VIII-6 possibly via its recruitment in a host ubiquitin-ligase complex in order to suppress plant immunity. Further research into RLCK-VIII role will enhance our understanding of the manipulation of plant immunity signaling by pathogen effectors.
Plasmodesmata (PD) facilitate the continuity of plasma membrane and cytoplasm between plant cells. They are crucial for intercellular communication and signaling. Plant pathogens have developed a diverse array of mechanisms to exploit the PD. There is increasing evidence that PD is actively involved in plant defense responses. Viral movement proteins alter PD architecture, cytoskeletal organization, and associated protein complexes, facilitating intercellular movement of viral genomes. Similarly, bacterial and fungal effectors target PD to suppress defense signaling and enhance colonization. During pathogen recognition, PD undergo dynamic closure as part of pattern-triggered immunity, largely mediated by callose deposition at PD neck regions. Over the past few years, significant progress has been made in elucidating the functions of PD in plant-pathogen interaction. However, there are still numerous critical areas that require attention. The current review emphasizes the crucial role of pathogen-PD interactions in shaping PD-molecular flux and explores their impact on hormone signaling and different cell types during intercellular movement of pathogens. This review emphasizes the need for deeper insights into PD regulation during plant–pathogen interactions, focusing on molecular targets exploited by pathogens. Elucidating the molecular mechanisms underlying PD-mediated defense will advance our understanding of plant immunity and aid in developing innovative strategies for sustainable disease management.
