Biosynthesized selenium nanoparticles (SeNPs) have attracted much attention because of their unique physical, chemical, and biological properties. The microbial reduction of selenium salts to SeNPs has great potential, while there is a lack of elite strains. In this study, we explored the reduction of Na₂SeO₃ by Streptomyces avermitilis into SeNPs. The colonies and hyphae of the strain and the synthesized SeNPs were characterized by optical microscopy, scanning electron microscopy (SEM), transmission electron microscope (TEM), energy dispersive spectrometry (EDS), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR). At the same time, the inhibitory activity of SeNPs on Fusarium oxysporum, the main pathogen causing root rot of Lycium barbarum, was studied. The results showed that S. avermitilis converted Na₂SeO₃ into SeNPs and tolerated 300 mmol/L Na₂SeO₃, demonstrating strong tolerance. S. avermitilis synthesized spherical SeNPs in the cytoplasm, and most of SeNPs had a diameter of about 100 nm and were released by hyphal fracture. The SeNPs synthesized by S. avermitilis were amorphous, and their surfaces were dominated by C and Se, with the existence of O, N and other elements. SeNPs had functional groups such as -OH, C=O, C-N, and C-H, which were closely related to the stability and biological activity of SeNPs. The SeNPs synthesized by S. avermitilis showcased significant inhibitory activity on F. oxysporum, and 25.0 μmol/mL SeNPs showcased the inhibition rate of 77.61% and EC₅₀ of 0.556 μmol/mL. In conclusion, S. avermitilis can tolerate high Na₂SeO₃ stress and mediate the synthesis of SeNPs. The synthesized SeNPs have good stability and strong inhibitory activity, demonstrating the potential application value in the preparation of SeNPs and the control of L. barbarum root rot.
Streptomyces/metabolism* ; Fusarium/drug effects* ; Lycium/microbiology* ; Selenium/metabolism* ; Nanoparticles/chemistry* ; Plant Diseases/microbiology* ; Metal Nanoparticles/chemistry* ; Antifungal Agents/pharmacology*

Rice (Oryza sativa L.) is an important food crop. The appearance of lesion mimics in rice leads to phytohormone disorders, which affects rice adaptation to environmental stresses and ultimately reduces the yield and quality. To explore whether the changes in the adaptability of rice lesion-mimic mutants to stressful environments are caused by the disorder of phytohormone metabolism in plants. In this study, we screened an ethyl methane sulfonate-treated population of the japonica cultivar 'Taipei 309' for a mutant with rust-like spots on leaves at the early tillering stage and brown-red spots at maturity and named it rsl1 (rust spotted leaf 1). Compared with the wild type, rsl1 showed decreases in plant height, panicle length, primary branch number, secondary branch number, filled grains per panicle, seed-setting rate, and 1 000-grain weight, and an increase in number of effective panicles. Genetic analysis indicated that rsl1 was controlled by a single recessive nuclear gene. RSL1 was localized between two molecular markers, B7-7 and B7-9, on rice chromosome 7 by map-based cloning. PCR sequencing of the annotated genes in this interval revealed a mutation of C1683A on the eighth exon of SPL5 (LOC_Os07g10390) in rsl1, which resulted in premature termination of protein translation. Exogenous phytohormone treatments showed that rsl1 was less sensitive to salicylic acid (SA), abscisic acid (ABA), and indo-3-acetic acid (IAA) and more sensitive to methyl jasmonate (MeJA) and gibberellin acid (GA) than the wild type. In addition, the survival rate of rsl1 was lower than that of the wild type under salt, alkali, drought, and high temperature stresses, and it was higher than that of the wild type under cold stress. Quantitative real-time polymerase chain reaction (qRT-PCR) results showed that RSL1 was involved in the regulation of ABA, SA, MeJA, IAA, and GA-related genes under abiotic stresses. The present study showed that the RSL1 mutation led to the appearance of lesion mimics and affected the growth, development, and stress resistance of rsl1 under abiotic stresses. The study of the functional mechanism of this gene can provide theoretical guidance for the research on rice stress resistance.
Oryza/microbiology* ; Stress, Physiological/genetics* ; Plant Diseases/genetics* ; Cloning, Molecular ; Chromosome Mapping ; Plant Growth Regulators/metabolism* ; Plant Proteins/genetics* ; Mutation ; Cyclopentanes ; Genes, Plant ; Plant Leaves/genetics* ; Oxylipins

In recent years, potato scab caused by pathogenic Streptomyces spp. has become widespread globally, with increasing damage severely compromising the commercial value and storability of tubers. The pathogens are transmitted through the soil and seeds of potato, while existing control technologies have demonstrated limited efficacy in preventing the colonization and spread of pathogens, which pose a critical bottleneck in the sustainable development of the potato industry. This study systematically examines the pathogen characteristics and pathogenic mechanisms, evaluates the impacts of soil nutrients and microbial community structure on disease severity, and analyzes limitations in current chemical control, biological control, and disease-resistant variety breeding approaches. We propose an integrated control strategy of disease-resistant varieties, phosphorus fertilizer reduction, fertilizer efficiency enhancement, and phosphorus-soluble antagonistic fungicides, aiming to provide novel research perspectives for achieving effective prevention and control of potato scab.
Solanum tuberosum/microbiology* ; Plant Diseases/prevention & control* ; Streptomyces/pathogenicity* ; Disease Resistance ; Fungicides, Industrial/pharmacology* ; Fertilizers ; Soil Microbiology

Filamentous fungi represent an important group of eukaryotic microorganisms with diverse ecological functions and ubiquitous distribution in various ecosystems. Among them, many species are closely associated with agriculture, functioning as major plant pathogens that cause yield losses and produce mycotoxins to compromise both the quality and safety of agricultural products. In recent years, the CRISPR/Cas system has emerged as a powerful and programmable genome editing tool, and it has been extensively applied to the genetic study of plant pathogenic fungi. This technology has greatly facilitated the investigation of pathogenic mechanisms, mycotoxin biosynthetic pathways and key gene functions, antifungal resistance, and rapid pathogen detection. This review summarizes the development of CRISPR/Cas systems and the key strategies for their application in plant pathogenic fungi and makes an outlook on the practical deployment. With the continuous advancement of gene editing technologies, emerging fungal-adapted editing systems hold great promise for advancing functional genomics and enabling innovations in disease-resistant breeding and sustainable crop protection.
Gene Editing/methods* ; Fungi/pathogenicity* ; CRISPR-Cas Systems/genetics* ; Plant Diseases/microbiology* ; Plants/microbiology* ; Genome, Fungal/genetics*

Bacillus velezensis DJ1 exhibits broad-spectrum antagonistic activity against diverse phytopathogenic fungi, while its biocontrol mechanisms against Fusarium graminearum, the causal agent of maize stalk rot, remain poorly characterized. In this study, we integrated genomics and transcriptomics to elucidate the antifungal mechanisms of strain DJ1. The results demonstrated that DJ1 inhibited F. graminearum with the efficacy of 64.4%, while its polyketide crude extract achieved the control efficacy of 55% in pot experiments against this disease. Whole-genome sequencing revealed a single circular chromosome (3 929 792 bp, GC content of 47%) harboring 12 biosynthetic gene clusters for secondary metabolites, six of which encoded known antimicrobial compounds (macrolactin H, bacillaene, difficidin, surfactin, fengycin, and bacilysin). Transcriptomic analysis identified 243 differentially expressed genes (152 upregulated and 91 downregulated, P < 0.05), which were potentially associated with the antagonistic activity against F. graminearum. KEGG enrichment analysis highlighted activation (P < 0.05) of cysteine/methionine metabolism, pentose phosphate pathway, and polyketide biosynthesis pathways, indicating that DJ1 employed synergistic strategies involving antimicrobial compound synthesis, energy metabolism enhancement, and nutrient competition to suppress pathogens. This study provides a theoretical foundation for developing novel microbial resources and application technologies to combat phytopathogenic fungi.
Fusarium/drug effects* ; Bacillus/metabolism* ; Plant Diseases/prevention & control* ; Antifungal Agents/pharmacology* ; Genomics ; Zea mays/microbiology* ; Transcriptome ; Gene Expression Profiling ; Antibiosis ; Multigene Family ; Multiomics

To develop biocontrol agents for the control of kiwifruit bacterial canker, we isolated a strain CXG2-5 with inhibitory activity against Pseudomonas syringae pv. actinidiae (Psa), the pathogen of kiwifruit bacterial canker, from the rhizosphere soil of kiwifruit by the plate confrontation test. The strain was identified by morphological observation, physiological and biochemical tests, and molecular biological methods. The indoor control efficacy of the strain was determined by the inoculation of the strain into detached branches with wounds and into leaf discs by vacuum infiltration. The ability of the strain to expand and colonize leaf veins was determined by fluorescent labeling and scanning electron microscopy. Subsequently, the strain was prepared into microcapsules, the field control efficacy of which was evaluated. The strain CXG2-5 was identified as Pseudomonas benzenivorans. It demonstrated good antagonistic activity against Psa, with an inhibition zone diameter of 22 mm and an inhibition rate of 72.7%. The preventive effects of the strain on kiwifruit bacterial canker were better than the therapeutic effects on both detached branches and leaves, with the preventive effects reaching 65% and 92.4%, respectively. The control effect of microcapsules of this strain in the field reached 60.89%, which was slightly lower than that of 20% kasugamycin and higher than that of Bacillus subtilis wettable powder. In conclusion, strain CXG2-5 serves as a candidate for the control of kiwifruit bacterial canker, and the prepared microcapsules have good value for development and application.
Actinidia/microbiology* ; Plant Diseases/prevention & control* ; Pseudomonas syringae ; Pseudomonas/isolation & purification* ; Capsules ; Antibiosis ; Biological Control Agents ; Pest Control, Biological/methods*

Fusarium head blight (FHB), caused by Fusarium graminearum, not only leads to severe yield losses but also poses a threat to food safety due to the mycotoxins produced by the pathogen. Since this disease is preventable but not curable, the current control mainly relies on chemical fungicides, the long-term use of which may lead to pathogen resistance and environmental pollution. To develop green control methods, we screened 13 biocontrol strains from the rhizosphere soil of wheat, among which strain No. 12 (identified as Pythium aphanidermatum) showed significant antifungal effects. In the plate confrontation test, this strain reduced the colony diameter of the pathogen by 69.2% (1.47 mm vs. 4.78 mm in the control group), with an inhibition rate of 77% (P < 0.01). Microscopic observation revealed obvious deformations in the pathogen hyphae, suggesting a lysing effect. The coleoptile experiment further confirmed that the pre-treatment with this strain reduced the incidence rate to 0. These findings provide new candidate strains for the biocontrol of FHB and offer a scientific basis for reducing the use of chemical fungicides and promoting sustainable agricultural development.
Triticum/growth & development* ; Fusarium/growth & development* ; Plant Diseases/prevention & control* ; Soil Microbiology ; Pest Control, Biological/methods* ; Pythium/physiology* ; Biological Control Agents ; Rhizosphere ; Fungicides, Industrial

Small RNAs (sRNAs), the key components of RNA interference (RNAi) or RNA silencing, can mediate cell-autonomous gene silencing and function as signaling molecules across species. Microbe-induced gene silencing (MIGS), which is based on interspecies RNAi, is an effective approach for controlling fungal diseases in crops. The enolase gene VdEno is essential for the growth and development of the fungal pathogen Verticillium dahliae, which causes cotton Verticillium wilt. In this study, we engineered Trichoderma harzianum (Th) to express the double-stranded RNA (dsRNA) targeting VdEno. The engineered strain Th-VdEnoi successfully generated VdEno-specific small interfering RNA (siVdEno). We further confirmed that Th-VdEnoi effectively induced VdEno silencing at the translational level. The results of crop protection assays revealed that the cotton plants co-inoculated with V. dahliae (strain V592) and Th-VdEnoi presented significantly reduced disease severity and lower fungal biomass in their roots than the control plants inoculated with V. dahliae alone or with V. dahliae and Th-GFPi (a control strain expressing GFP-targeting dsRNA). Collectively, our findings demonstrate that VdEno is an effective target for controlling cotton Verticillium wilt and confirm that MIGS is a promising strategy for managing soil-borne fungal pathogens in crops. MIGS provides strong technical support for reducing the application of conventional chemical pesticides, developing eco-friendly biopesticides, and facilitating the sustainable development of agriculture.
Gossypium/microbiology* ; Plant Diseases/prevention & control* ; Gene Silencing ; Ascomycota/genetics* ; RNA Interference ; RNA, Double-Stranded/genetics* ; Hypocreales/genetics* ; RNA, Small Interfering/genetics* ; Verticillium/genetics* ; Fungal Proteins/genetics*

To clarify the species, pathogenicity, and distribution of the pathogens causing the root rot of Atractylodes lancea in Hubei province, the tissue separation method was used to isolate the pathogens from root rot samples in the main planting areas of A. lancea in Hubei. Based on the preliminary identification of the Fusarium genus by the internal transcribed spacer(ITS) sequence, three housekeeping genes, EF1/EF2, Btu-F-FO1/Btu-F-RO1, and FF1/FR1, were amplified and sequenced. Subsequently, a phylogenetic tree was constructed based on these TEF gene sequences to classify the pathogens. The pathogenicity of these strains was determined using the root irrigation method. A total of 194 pathogen strains were isolated using the tissue separation method. Molecular identification using the three housekeeping genes identified the pathogens as F. solani, F. oxysporum, F. commune, F. equiseti, F. tricinctum, F. redolens, F. fujikuroi, F. avenaceum, F. acuminatum, and F. incarnatum. Among them, F. solani and F. oxysporum were the dominant strains, widely distributed in multiple regions, with F. solani accounting for approximately 54% of the total isolated strains and F. oxysporum accounting for approximately 34%. Other strains accounted for a relatively small proportion, totaling approximately 12%. The results of pathogenicity determination showed that there were certain differences in pathogenicity among strains. The analysis of the pathogenicity differentiation of the widely distributed F. solani and F. oxysporum strains revealed that these dominant strains in Hubei were mainly highly pathogenic. This study determined the species, pathogenicity, and distribution of the pathogens causing the root rot of A. lancea in Hubei province. The results provide a scientific basis for further understanding the root rot of A. lancea and its epidemic occurrence and scientifically preventing and controlling this disease.
Plant Diseases/microbiology* ; Atractylodes/microbiology* ; Phylogeny ; Plant Roots/microbiology* ; Fusarium/classification* ; China ; Virulence ; Fungal Proteins/genetics*

Aconitum kusnezoffii is a perennial herbaceous medicinal plant of the family Ranunculaceae, with unique medicinal value. Damping off is one of the most important seedling diseases affecting A. kusnezoffii, occurring widely and often causing large-scale seedling death in the field. To clarify the species of the pathogen causing damping off in A. kusnezoffii and to formulate an effective control strategy, this study conducted pathogen identification, research on biological characteristics, and evaluation of fungicide inhibitory activity. Through morphological characteristics, cultural traits, and phylogenetic tree analysis, the pathogen causing damping off in A. kusnezoffii was identified as Rhizoctonia solani, belonging to the AG5 anastomosis group. The optimal temperature for mycelial growth of the pathogen was 25-30 ℃, with OA medium as the most suitable medium, pH 8 as the optimal pH, and sucrose and yeast as the best carbon and nitrogen sources, respectively. The effect of light on mycelial growth was not significant. In evaluating the inhibitory activity of 45 chemical fungicides, including 30% hymexazol, and 4 biogenic fungicides, including 0.3% eugenol, it was found that 30% thifluzamide and 50% fludioxonil had significantly better inhibitory effects on R. solani than other tested agents, with EC_(50) values of 0.129 6,0.220 6 μg·mL~(-1), respectively. Among the biogenic fungicides, 0.3% eugenol also showed an ideal inhibitory effect on the pathogen, with an EC_(50) of 1.668 9 μg·mL~(-1). To prevent the development of resistance in the pathogen and to reduce the use of chemical fungicides, it is recommended that the three fungicides above be used in rotation during production. These findings provide a theoretical basis for the accurate diagnosis and effective control strategy for R. solani causing damping off in A. kusnezoffii.
Fungicides, Industrial/pharmacology* ; Plant Diseases/microbiology* ; Rhizoctonia/growth & development* ; Aconitum/microbiology* ; Phylogeny ; Mycelium/growth & development*