Search Results (1,463)

Amorphophallus spp., valued as both crops and medicinal plants, are highly susceptible to soft rot disease, causing substantial yield and economic losses during cultivation and storage. Calcium nanoparticle (CaNP) fertilizer not only has the potential to enhance crop yields but also plays a crucial role in the control of crop pests and diseases. However, its application in the control of soft rot disease in konjac has not yet been investigated. In this study, the antibacterial efficacy of CaNP fertilizer against the typical soft rot pathogen P. aroidearum MY11 in Amorphophallus konjac (A. konjac) was investigated. It was found that CaNP fertilizer significantly inhibited the growth, motility ability and the activity of cell wall-degrading exoenzymes of P. aroidearum MY11. Transmission electron microscopy revealed that the morphology of bacterial cells treated with CaNPs did not change significantly, but significant particle deposition was observed within the cells. Furthermore, CaNPs pretreatment could reduce the reactive oxygen species (ROS) content, activate the antioxidant enzyme system, and enhance the photosynthetic capacity of A. konjac plants. qRT-PCR analysis revealed that CaNPs pretreatment might enhance the resistance of A. konjac plants to the soft rot pathogen MY11 by activating the jasmonic acid (JA), salicylic acid (SA) signaling pathway and the cell wall stress response pathway. This research provides a new candidate for nanopesticides that can be used to control the bacterial soft rot disease of konjac. Full article

Eucalyptus bacterial wilt in China, caused predominantly by Ralstonia pseudosolanacearum, severely threatens Eucalyptus plantation management in China and demands plant-derived alternatives to conventional bactericides. This study evaluated the in vitro antibacterial activities and underlying molecular mechanisms of two differentially substituted coumarin derivatives, daphnetin (DAP) and 6-methylcoumarin (MC), against a eucalyptus-derived R. pseudosolanacearum strain. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were determined using broth microdilution assays. Quantitative phenotypic assays were conducted to evaluate the effects of sub-lethal concentrations on biofilm formation, swimming motility, and extracellular polysaccharide (EPS) accumulation. Furthermore, high-throughput RNA sequencing integrated with GO and KEGG enrichment analyses was employed to characterize the genome-wide transcriptomic responses. Antimicrobial susceptibility testing demonstrated that DAP possessed superior bactericidal efficacy, yielding lower MIC (62.5 μg/mL) and MBC (250 μg/mL) values than MC. Conversely, sub-lethal MC exhibited a more pronounced, early-stage suppression of flagellum-dependent swimming motility and biofilm maturation. Both compounds consistently attenuated EPS production. Transcriptomic analysis revealed distinct yet partially convergent regulatory networks: DAP primarily exerted metabolic strangulation by downregulating genes governing aerobic respiratory chains and peripheral carbon/nitrogen pathways, whereas MC targeted collective behavior and active pathogenesis, systematically downregulating the expression of genes associated with flagellar assembly, quorum sensing, and Type III and VI secretion systems. Notably, both pathways converged downstream to repress the master virulence regulator xpsR and the epsA-P operon. These findings provide valuable insights into the potential molecular pathways affected by DAP and MC, offering a useful reference for future exploration of botanical formulations for ecologically responsible forest disease control. Full article

Soil salinity and bacterial spot of tomato (BST), caused by Xanthomonas perforans, are major abiotic and biotic stresses limiting tomato production, particularly in Florida. While their individual effects are well documented, the impact of soil salinity on BST has not yet been investigated. This greenhouse study evaluated how increasing irrigation water salinity (electrical conductivity [EC] = 0.5, 3, 5, or 7 dS m⁻¹) affected tomato growth, physiology, BST severity, fruit quality, and transcriptomic responses. Salinity reduced plant growth and BST severity but did not directly affect X. perforans populations. Results indicated that reduced plant physiological activity (net CO₂ assimilation [A], transpiration [E], and stomatal conductance [g_s]) contributes to lower disease levels. Increased salinity led to more solute concentrations, altered sugar metabolism, and improved perceived taste, as supported by taste panel, osmolality, and transcriptomic analyses. They also showed that transcriptional responses to salinity (EC = 7 dS m⁻¹) and X. perforans infection were strongly time-dependent. Salt-treated plants exhibited fewer differentially expressed genes following inoculation, whereas comparisons between EC 7-treated and control plants revealed extensive salinity-induced reprogramming. KEGG analysis indicated enrichment of photosynthesis, carbon metabolism, amino acid biosynthesis, and ribosome pathways, while defense-related pathways, including MAPK signaling and plant–pathogen interaction, were downregulated, suggesting that tomato prioritized adaptation to salinity over pathogen defense. Full article

Biological control strategies are increasingly being explored as sustainable alternatives for managing rice blast disease caused by Magnaporthe oryzae. In this study, we characterized three Bacillus pumilus isolates (DC01, DC09, and DC13) and evaluated their antifungal and plant-beneficial properties against M. oryzae. Whole-genome sequencing revealed multiple biosynthetic gene clusters associated with the production of antimicrobial metabolites. All three isolates inhibited fungal growth in dual-culture assays, whereas heat-stable diffusible antifungal activity was primarily associated with the cell-free supernatants of DC09 and DC13. Exposure to bacterial supernatants disrupted fungal development, inducing abnormal hyphal morphology in M. oryzae characterized by bulbous swelling, altered polarity, and increased branching. Volatile organic compound assays further revealed that the DC isolates suppress fungal growth in the absence of physical contact. The isolates additionally inhibited the growth of other phytopathogenic fungi and selected human bacterial pathogens. All strains exhibited plant growth-promoting traits, including indole-3-acetic acid production and osmotic stress tolerance, whereas DC09 also displayed phosphate-solubilizing activity. Importantly, soil inoculation with the DC isolates significantly reduced rice blast disease severity and induced expression of defense-associated genes involved in jasmonic acid/ethylene signaling and immune priming. Collectively, these findings identify the DC isolates, particularly DC09 and DC13, as promising multi-mechanistic biological control agents for sustainable rice blast management. Full article

Quorum sensing (QS) is critically involved in mediating microbial interactions and serves as a central regulatory mechanism in bacterial pathogenesis. As an emerging countermeasure, quorum quenching (QQ) suppresses QS-regulated virulence through enzymatic or chemical disruption of signal systems. N-acyl homoserine lactone (AHL), an evolutionarily conserved QS signal, coordinates the pathogenicity of multiple plant pathogens, particularly Dickeya zeae, which causes soft rot disease in various crops and leads to substantial agricultural losses. In this study, the QQ strain Acinetobacter schindleri XJ-10 was evaluated for its capacity to degrade AHL and attenuate the pathogenicity of D. zeae EC1 in host plants. Notably, strain XJ-10 exhibited efficient AHL degradation at 0.2 mmol/L within 24 h, achieving a degradation efficiency of 98.80%. Subsequently, gas chromatography–mass spectrometry (GC-MS) analysis identified N-hexanoyl-L-homoserine lactone and propanamide as key intermediates during AHL degradation, confirming complete mineralization to CO₂ and H₂O. Based on the structural characterization of AHL and its intermediates, the metabolic pathway within strain XJ-10 was proposed. The degradation pathway initiates with the hydrolysis of the ester ring of N-hexanoyl-L-homoserine lactone, generating N-hexanoyl-L-homoserine. Subsequent carbon–nitrogen bond scission is predicted to yield N-cyclohexyl-propanamide, which is further catabolized to produce hexanamide and propanamide. Furthermore, strain XJ-10 exhibited biocontrol activity against soft rot disease affecting potato (Solanum tuberosum), radish (Raphanus sativus), and Chinese cabbage (Brassica rapa subsp. pekinensis), as its crude enzyme extract effectively reduced disease incidence and severity in planta. While strain XJ-10 showed no detectable acylase activity, it exhibited significant degradation activity against AHL, suggesting a distinct QQ mechanism. Collectively, these findings broaden the scope of QQ-based biocontrol strategies and enhance mechanistic insights into managing bacterial diseases through QS modulation. Full article

A plant pathogen is a deterministic factor affecting the plant microbiome. However, whether the influence of different pathogen species on the plant microbiome is consistent is not well-known. In this study, mulberry leaves with similar spots caused by two diseases—mulberry brown spot (MBS, caused by Neophloeospora maculans) and mulberry snags rotten leaves disease (MSRL, caused by Boeremia exigua var. mori)—along with asymptomatic leaves, were collected. Their endophytic fungal and bacterial communities were sequenced. The occurrence of MSRL reduced leaf fungal richness and diversity (observed species from 329 to 203; Shannon diversity index from 3.6 to 2.6, p < 0.05; phylogenetic diversity index from 45.8 to 20.6, p < 0.05), along with leaf bacterial diversity; in contrast, the occurrence of MBS had little effect on both fungal and bacterial richness and diversity. Both diseases significantly altered the composition and structure of leaf fungal communities, whereas only MBS did so for bacterial communities. For the dominant genera, the fungal genera, except Cercospora, were differently affected by the occurrence of MBS and MSRL, while the bacterial genera Pseudomonas (from 8.3% to 30.6%, p < 0.05 for MBS; from 23.1% to 28.1% for MSRL), Massilia (0.2% to 7.7%, p < 0.05; 2.1% to 6.1%), Chryseobacterium (0.1% to 0.3%; 2.7% to 7%), Pantoea (2.6% to 3.7%; 0.4% to 1%), and Aureimonas (0.7% to 1.4%; 1.3% to 1.7%) were consistently enriched by both diseases. In addition, Chryseobacterium (LDA score = 4.6, p < 0.01) was detected as a biomarker after the occurrence of MSRL. Intriguingly, there were four times more significant fungi–bacteria positive associations induced by the occurrence of MSRL compared to MBS (10.2% to 2.5%). Taken together, the responses of mulberry leaf microbiome to pathogen infection vary in response to the pathogen species; although several bacterial genera were consistently enriched, whether their enrichment reflects their antagonistic roles in fungal—bacterial inter-kingdom interactions remains to be determined and should be interpreted with further experimental tests. Full article

Rice blast and bacterial blight are two major diseases that threaten rice production worldwide. Developing rice cultivars with both disease resistance and desirable grain quality is an important objective in modern rice breeding. In this study, R1179 carrying Pi2, Wx^b and Alk^b was crossed with IRBB7 carrying Xa7, Wx^b and Alk^b. Marker-assisted selection (MAS) was applied to an F₂ population of 1123 plants, and a line, G163, combining Pi2, Xa7, Wx^b and Alk^b, was developed. Disease resistance evaluation showed that G163 retained the blast resistance conferred by Pi2 and the bacterial blight resistance conferred by Xa7, exhibiting resistance to the tested isolates of both pathogens. Grain quality assessment indicated that G163 possessed favorable milling, appearance and eating quality traits. Rapid Visco Analyzer (RVA) profiling further indicated desirable starch pasting properties. In conclusion, the rice line G163 carrying Pi2, Xa7, Wx^b and Alk^b was successfully developed through MAS. The results provide a useful germplasm resource for breeding rice cultivars with combined disease resistance and desirable grain quality. Full article

Soybean diseases caused by fungal, bacterial, and viral pathogens represent a major constraint to global agricultural productivity. Although molecular phylogenetic analyses have advanced the understanding of pathogen evolution, the extent to which disease phenotypes reflect evolutionary relationships remains poorly understood. In this study, we developed an integrative framework combining deep learning-based phenotypic analysis with phylogenetic inference to investigate the relationship between soybean disease symptoms and pathogen evolution. An EfficientNet-B0 convolutional neural network (CNN) was trained to classify 10 soybean disease classes comprising 703 leaf images and achieved a mean cross-validation accuracy of 98.72 ± 1.17%, a weighted F1-score of 98.74 ± 1.16%, and a macro F1-score of 98.47 ± 1.74%. Evaluation on a held-out test set generated through image-level partitioning yielded an accuracy of 96.19%, a weighted F1-score of 96.28%, and a macro F1-score of 95.86%. Latent feature embeddings revealed a structured phenotypic space with clear separation among most disease classes and enabled quantitative analyses of phenotypic similarity. To provide biological context, taxonomy-derived distance matrices and sequence-based phylogenetic analyses of the fungal subset using 28S rRNA sequences were compared with CNN-derived phenotypic representations. A Mantel test identified a moderate and statistically significant association between phenotypic and phylogenetic distances (Spearman r = 0.3393, p = 0.0050), indicating that pathogen evolutionary history contributes to disease phenotype while explaining only part of the observed phenotypic variation. Overall, the results demonstrate that deep learning effectively captures biologically meaningful phenotypic information while highlighting that disease symptoms arise from the combined influence of pathogen evolution, host responses, and environmental conditions. This study provides an integrative framework for combining image-based phenotyping with phylogenetic analysis to support biologically informed interpretation of plant disease phenotypes. Full article

Amomum villosum is an evergreen perennial herb widely distributed in tropical and subtropical regions, with significant economic and medicinal importance. Throughout the cultivation process, it faces severe fungal disease problems that significantly impact its yield and quality. In July 2025, leaf spot disease with a 56% incidence was observed on A. villosum in Wenshan, Yunnan, China. Affected leaves initially developed irregular grayish-white lesions surrounded by brown margins. As symptom development progressed, semi-submerged black spots formed on the lesion surfaces. Severe infections resulted in premature leaf abscission and, ultimately, death of the entire plant. To identify the pathogen responsible, we conducted isolation and pathogenicity studies. Through morphological characterization, phylogenetic analysis (ITS, LSU, and TUB), and pathogenicity tests, Pestalotiopsis microspora was determined as a pathogen. Koch’s postulates were fulfilled on attached leaves. After 15 days, typical necrotic lesions appeared on inoculated leaves, while controls remained symptom-free. This is the first report of A. villosum leaf spot caused by P. microspora in China. Biocontrol assays revealed that Trichoderma harzianum T15 and T. asperellum T16 exhibited significant antagonistic activity against P. microspora, with inhibition rates of 44.77% and 50.70%, respectively. In addition, Bacillus velezensis SWFU41, isolated from healthy A. villosum leaves, showed superior disease suppression, achieving a control efficacy of 60.52%. Compared with the fungal biocontrol agents, B. velezensis demonstrated greater inhibitory activity against the pathogen, suggesting that bacterial antagonists may provide a more effective biological control strategy for managing A. villosum leaf spot disease. This is the first report of P. microspora-caused leaf spot disease on A. villosum. Furthermore, the comparative evaluation of fungal and bacterial antagonists demonstrated that B. velezensis SWFU41 outperformed T. harzianum and T. asperellum in disease suppression, highlighting its potential as a promising biocontrol agent for sustainable disease management. These findings provide a scientific basis for pathogen monitoring, epidemiological studies, and the development of integrated biological control strategies for A. villosum cultivation. Full article

Soybean root rot caused by Fusarium oxysporum is an important soil-borne disease that affects soybean growth and disrupts rhizosphere microbial communities. However, how rhizosphere microbiomes respond to different levels of disease severity remains poorly understood. In this study, a five-level root rot severity gradient (F0–F4) was established using a carrier-matched inoculation design, and changes in soybean growth, rhizosphere soil properties, enzyme activities, microbial community composition, and functional potential were investigated using shotgun metagenomic sequencing. Increasing disease severity reduced soybean growth, with leaf area decreasing from 312.98 cm² in F0 to 32.45 cm² in F4. Root rot progression altered rhizosphere microbial communities, with fungal communities showing stronger responses than bacterial communities. The bacterial Chao1 richness index increased by 34.6% in F4 compared with F0, whereas fungal Shannon diversity decreased by 46.7%. Taxonomic analysis revealed clear shifts in microbial community composition, with Fusarium becoming strongly enriched under diseased conditions, increasing from 16.9% in F0 to maximum relative abundance of 68.8% in F2 and remaining highly abundant at 61.5% in F4, while Trichoderma decreased from 7.3% to 2.2% and Rhizophagus declined from 38.1% to nearly undetectable levels. Metagenomic functional profiling revealed disease-associated changes in microbial functional potential, particularly in pathways related to metabolism, membrane transport, signal transduction, and secondary metabolite biosynthesis. In addition, soil physicochemical properties and enzyme activities varied across the disease severity gradient, indicating changes in the rhizosphere environment during disease development. Overall, soybean root rot progression was associated with coordinated changes in plant performance, soil biochemical characteristics, microbial community structure, and functional potential, with fungal communities exhibiting stronger responses to disease-associated disturbance than bacterial communities. Full article

Pseudomonas savastanoi pv. phaseolicola, the causal agent of halo blight of bean, is a useful model for studying bacterial adaptation to plant infection. Although its toxins, effectors, population dynamics, and epidemiology have been investigated for decades, these aspects have often been treated separately. This narrative synthesis reinterprets the available literature within a stage-based infection framework encompassing host-surface colonization, establishment of a compatible apoplastic habitat, evasion of host immune responses, multiplication, and spread to another compatible host. Particular attention was given to studies published after the last major review on this pathovar, whereas older studies were retained when they represented primary reports, classical experimental evidence, or information that has not been superseded. The review shows that successful infection is best understood as involving opportunistic entry, rapid transition from an epiphytic to a pathogenic lifestyle, effector-dependent immune suppression, phaseolotoxin-mediated manipulation of host primary metabolism, the exploitation or establishment of hydrated apoplastic conditions, and environmentally driven dissemination. It also distinguishes experimentally supported mechanisms from unresolved or hypothesis-generating areas, including stomatal reopening, micronutrient acquisition, population-level division of labor, alternative hosts, and symptomless reservoirs. The major synthesis emerging from this review is that the infection biology of P. savastanoi pv. phaseolicola cannot be reduced to individual virulence factors because disease development depends on how these factors are coordinated with host-derived resources, immune constraints, and environmental opportunities. Full article

Southern blight caused by Sclerotium rolfsii is a devastating soil-borne disease of Aconitum carmichaelii, a medicinal plant widely cultivated in China. Biological control using beneficial bacteria offers a sustainable alternative to chemical fungicides. This study investigated the influence of Bacillus subtilis FZ-7 on rhizosphere microbiome assembly and disease suppression in A. carmichaelii under field conditions. Four treatments were established: uninoculated control (C group), single inoculation with B. subtilis (B group), single inoculation with S. rolfsii (S group), and co-inoculation of S. rolfsii and B. subtilis (BS group). Plant biomass, soil physicochemical properties, and rhizosphere bacterial and fungal communities were analyzed using high-throughput sequencing of 16S rRNA and ITS genes, along with co-occurrence network analysis. Results showed that B. subtilis inoculation suppressed this growth suppression. B. subtilis alone enhanced both bacterial and fungal diversity. PCoA and LEfSe analyses revealed distinct microbial community structures among treatments, with biomarkers such as Lactobacillus, Candidatus Nitrosotalea, Rhodanobacter, and Sphingomonas for bacteria, and Trichocladium, Conocybe, Plectosphaerella, and Athelia for fungi. Co-occurrence network analysis indicated that co-inoculation of S. rolfsii and B. subtilis partially restored cooperative microbial associations. Soil organic matter, pH, and cation exchange capacity were the main environmental factors shaping microbial community composition. Shoot fresh weight in BS recovered to 2.98 kg and rhizome fresh weight to 3.72 kg, representing 73.0% and 41.2% increases over the S treatment. Additionally, the disease index was reduced by 55.26 in BS compared with the control group. Nay more, Bacillus, Chujaibacter, and Rhodanobacter taxa were significantly enriched in BS group. In conclusion, B. subtilis FZ-7 effectively mitigates southern blight in A. carmichaelii by modulating rhizosphere microbial assembly, enriching beneficial taxa, and stabilizing microbial co-occurrence networks, highlighting its potential as a biocontrol agent for sustainable medicinal plant production. Full article

Cotton damping-off caused by Rhizoctonia solani restricts seedling establishment, and locally adapted biocontrol isolates are potential components of sustainable disease management. This study evaluated Pseudomonas chlororaphis-like isolate M6 and tested whether molecular profiles in M6-protected plants differed from those in Pathogen-infected plants in directions that moved toward Healthy Control levels. Culturable bacteria from root-associated soils were screened against R. solani by dual-culture assays, and M6 was evaluated in a greenhouse cotton damping-off assay. RNA sequencing (RNA-seq) and untargeted liquid chromatography–mass spectrometry (LC–MS) data from Healthy Control, Pathogen-infected, and M6-protected plants at 0 and 7 d were analyzed using the Pathogen-infected versus Healthy Control and M6-protected versus Pathogen-infected contrasts. M6 produced the highest inhibition among the candidate isolates (81.9%). Under greenhouse conditions, the M6-protected treatment had lower disease incidence (22.2% versus 88.9%) and disease index (16.4 versus 76.8) than the Pathogen-infected treatment. At 7 d, the primary false-discovery-rate-controlled analysis identified 4457 transcripts and 1620 LC–MS features for which the change between M6-protected and Pathogen-infected plants was opposite to the pathogen-associated change and the M6-protected group mean was closer to the Healthy Control mean. Additional nominal-p-value-only results were retained as exploratory. The two contrasts involved redox regulation, phenylpropanoid/benzenoid-related metabolism, hormone/defense signaling, protein synthesis and central metabolism. Antioxidant enzyme and quantitative reverse transcription PCR (qRT-PCR) data provided independent support for selected redox- and defense-associated differences. Because pathogen biomass, bacterial colonization and antagonism-deficient mutants were not assessed, the molecular profiles are interpreted as association-based features of the protected state rather than evidence that host recovery caused disease reduction. Most LC–MS annotations are putative and were not confirmed with authentic standards. Full article

Pre- and postharvest losses caused by fungal infections represent one of the greatest constraints in agricultural production worldwide. Due to increasingly stringent regulations, as well as environmental and health concerns associated with their use, synthetic fungicides have been restricted, driving the development and application of sustainable alternatives within the framework of integrated plant disease management. Among these, Actinobacteria (also referred to as Actinomycetota) have attracted considerable attention over the past decades due to their versatile metabolites and plant growth-promoting properties, supporting their potential application as bacterial biocontrol agents. Their activity against phytopathogenic fungi is largely associated with direct antagonistic mechanisms. Currently, special attention is paid to the excreted secondary metabolites, lytic enzymes, volatile organic compounds and their in vitro antifungal activity. Therefore, this review summarizes current knowledge on these direct mechanisms, aiming to support the future application of actinobacteria and their metabolites as part of biological plant disease management strategies. Full article

Cannabis sativa L. is a multipurpose plant widely cultivated for fiber, food, medicinal products, and the production of bioactive compounds, including psychoactive cannabinoids. Fungal endophytes are a promising source of antimicrobial compounds used for biological control and sustainable crop production. However, the fungal endophytes associated with C. sativa have been poorly investigated, and their biological activities are still largely unexplored. Thus, this study aimed to identify fungal endophytes from C. sativa (marijuana and hemp biotypes) and to screen for their antagonistic activities against some plant pathogens. Based on ITS sequence analysis, a total of 103 fungal endophyte isolates (21 genera) were preliminarily identified from both biotypes, including 62 isolates (13 genera) from hemp and 41 isolates (nine genera) from marijuana. Fusarium was the dominant genus found in hemp (45%), while Nigrospora was the dominant genus isolated from marijuana (32%). Ten selected fungal endophytes were evaluated for in vitro antagonistic activity against four bacterial pathogens, Pectobacterium spp. (PC 01 and PC 02) and Ralstonia solanacearum (RA 01 and RA 02), and four fungal pathogens, Fusarium solani (FU 01), F. oxysporum (FU 02), and Sclerotium sp. (SC 01 and SC 02), all of which are causal agents of potato diseases. Among the tested fungal endophytes, Colletotrichum sp. (SLLC-M24) and Nigrospora sp. (SLLC-H15) exhibited the strongest antifungal activity against Fusarium spp. (FU 01 and FU 02), with inhibition rates ranging from 56 to 64%. In addition, Pestalotiopsis sp. (SLLC-H5) demonstrated effective antibacterial activity against all tested bacterial pathogens, producing inhibition zones ranging from 19 to 23 mm. This finding represents an important step toward discovering novel and promising endophytes associated with Cannabis and their biological control potential for utilization in sustainable agriculture. Full article