Search Results (364)

Tree diseases affecting Camellia japonica have emerged as a significant threat to the health and longevity of this ornamental tree, particularly in countries where this tree species is widely distributed and cultivated. Among these, Pestalotiopsis spp. have been frequently reported and are considered one of the most impactful fungal pathogens, causing leaf blight or leaf spot, in multiple countries. Understanding the etiology and distribution of these diseases is essential for effective management and conservation of C. japonica populations. The traditional methods based on pathogen isolation and pure culture cultivation for diagnosis of tree diseases are labor intensive and time-consuming. In addition, the frequent coexistence of the major pathogens with other endophytes within a single C. japonica tree, coupled with inconsistent symptom expression and the occurrence of pathogens in asymptomatic hosts, further complicates disease diagnosis. These challenges highlight the urgent need to develop more rapid, accurate, and efficient diagnostic or monitoring tools to improve disease monitoring and management on trees, including C. japonica. To address these challenges, we applied a metagenomic approach to screen fungal communities within C. japonica trees. This method enabled comprehensive detection and characterization of fungal taxa present in symptomatic and asymptomatic tissues. By analyzing the correlation between fungal dominance and symptom expression, we identified key pathogenic taxa associated with disease manifestation. To validate the metagenomic approach, we employed a combined strategy integrating metagenomic screening and traditional fungal isolation to monitor foliar diseases in C. japonica. The correlation between dominant taxa and symptom expression was confirmed. Simultaneously, traditional isolation enabled the identification of a novel species, Pestalotiopsis, as the causal agent of leaf spot disease on C. japonica. In addition to confirming previously known pathogens, our study led to the discovery and preliminary characterization of a novel fungal taxon with pathogenic potential. Our findings provide critical insights into the fungal community of C. japonica and lay the groundwork for developing improved, rapid diagnostic tools for effective disease monitoring and management of tree diseases. Full article

Brown spot, caused by Alternaria alternata, is the most important leaf fungal disease threatening kiwifruit production in China, and it is typically controlled through the application of fungicides, such as procymidone and difenoconazole. To date, fungicide resistance development has not yet been systematically reported for the pathogen of kiwifruit. A total of 135 single-conidium A. alternata isolates were collected from different cities in Zhejiang Province, China. Alternaria alternata developed prevailing resistance to procymidone and initial resistance to difenoconazole, with resistance frequencies of 60.7 and 13.3%, respectively. Positive cross-resistance was observed between procymidone and iprodione but not between procymidone and difenoconazole, tebuconazole, prochloraz, pydiflumetofen, pyraclostrobin, or thiophanate-methyl. Moreover, no cross-resistance was observed between difenoconazole and all other tested fungicides, including the two other demethylation inhibitors, tebuconazole and prochloraz. A fitness penalty was not detected in procymidone-resistant (Pro^R) or difenoconazole-resistant (Dif^R) isolates. However, double-resistant (Pro^R Dif^R) isolates had a fitness penalty, showing significantly decreased sporulation, germination, and pathogenicity. The P894L single point mutation, caused by the change from CCA to CTA at the 894th codon of Os1, was detected in Pro^R isolates. Molecular dynamic simulation showed that the P894L mutation significantly decreased the inhibitory activity of procymidone against AaOs1 in A. alternata. These results provide insight into the development and characteristics of fungicide resistance, offering guidance for the study and management of kiwifruit diseases. Full article

Weeds compete with crops for resources, posing multiple negative impacts for agricultural production systems and triggering degradation of ecosystem services (e.g., alterations in the soil microbial community structure). Under the guidance of green plant protection, the development of efficient biocontrol strains with environmentally friendly characteristics has become a crucial research direction for sustainable agriculture. This study aimed to develop a fungal bioherbicide by isolating and purifying a pathogenic fungal strain (JZ-5) from infected redroot pigweed (Amaranthus retroflexus L.). The strain exhibited pathogenicity rates ranging from 23.46% to 86.25% against six weed species, with the most pronounced control efficacy observed against henbit deadnettle (Lamium amplexicaule L.), achieving a pathogenicity rate of 86.25%. Through comprehensive characterization of cultural features, morphological observations, and molecular biological identification, the strain was taxonomically classified as Fusarium oxysporum. Scanning electron microscopy revealed that seven days post-inoculation, F. oxysporum JZ-5 formed dense mycelial networks on the leaf surfaces of cluster mallow (Malva verticillata L.), causing severe tissue damage. Safety assessments demonstrated that the spore suspension (10⁴ spores/mL) had no adverse effects on three crops: hulless barley (Hordeum vulgare var. coeleste L.), wheat (Triticum aestivum L.), and potato (Solanum tuberosum L.). These findings suggest that F. oxysporum strain JZ-5 warrants further investigation as a potential bioherbicide for controlling three problematic weed species—Chenopodium album L. (common lambsquarters), Elsholtzia densa Benth. (dense-flowered elsholtzia), and Lamium amplexicaule L. (henbit deadnettle)—in cultivated fields of hulless barley (Hordeum vulgare var. coeleste L.), wheat (Triticum aestivum L.), and potato (Solanum tuberosum L.). This discovery provides valuable fungal resources for ecologically sustainable weed management strategies, contributing significantly to the advancement of sustainable agricultural practices. Full article

Soil-borne fungal pathogens such as Sclerotium spp., Rhizoctonia spp., and Macrophomina spp. pose significant threats to global agriculture, with soybean crops among the most severely affected due to damping-off disease. These pathogens cause substantial yield losses, making their management a critical concern. In this study, we investigated the potential of Bacillus siamensis BCL, a novel Neotropical strain, as an eco-friendly solution for managing Sclerotium, Rhizoctonia, and Macrophomina species. The strain exhibited strong antifungal activity, significantly inhibiting fungal growth in vitro, with the greatest suppression observed against Macrophomina spp., reaching up to 81%. In vivo assays further confirmed the biocontrol potential of B. siamensis. When applied at 10⁶ colony-forming units (CFU)/mL, the strain reduced disease symptoms and improved plant growth parameters—including root length, shoot biomass, and leaf number—compared to untreated, infected controls. The protective effect varied by pathogen, with the most significant recovery in root length observed against Macrophomina spp. (85%) and Sclerotium spp. (78%). In preventive treatments, fermentation extracts of the B. siamensis strain suppressed disease progression, although they did not promote seedling growth. A genomic analysis of B. siamensis BCL revealed genes encoding antimicrobial secondary metabolites, including terpenes, fengycins, and surfactins. These findings highlight B. siamensis BCL as a promising candidate for sustainable crop protection and a valuable resource for developing novel antimicrobial strategies in agriculture. Full article

C2H2 zinc finger (C2H2-ZF) transcription factors, characterized by the presence of a conserved ZnF-C2H2 domain, are widespread among plant-pathogenic fungi such as Magnaporthe oryzae, Fusarium graminearum, and Sclerotinia sclerotiorum and have critical roles in the regulation of fungal growth, development, stress adaptation, and secondary metabolism. However, little is known about the presence and roles of C2H2-ZF transcription factors in Setosphaeria turcica (syn. Exserohilum turcicum), the causal agent of northern corn leaf blight. To address this gap, we identified the complete set of C2H2-ZF transcription factors in the S. turcica genome and characterized their structural characteristics, physicochemical properties, and protein–protein interaction network. We then used RNA sequencing to profile their expression dynamics during fungal development and host infection. The 27 S. turcica C2H2-ZF proteins were classified into three major subfamilies and contained six conserved motifs. All 27 genes were transcribed during 5 stages of fungal development, and 24 were expressed during the infection of susceptible maize, suggesting that they function in both fungal growth and pathogenesis. This study represents the first systematic characterization of C2H2-ZF proteins in S. turcica, offering insight into their potential roles in pathogenicity and establishing a foundation for future functional studies of individual family members. Full article

Phosphonate-based fungicides are believed to control fungal diseases while also supplying nutrients to plants. However, opinions differ on whether they truly serve as nutrients for plants, and the residues of their transformation products have not yet been thoroughly evaluated or mathematically characterized. To address this gap, this study analyzed data from a two-factorial experiment investigating the effects of Agrifos 400 (potassium phosphonate) application. The experiment involved two soil types: red basalt soil and an organically enriched soil. Three-month-old pepper plants (Piper nigrum L.) were treated with Agrifos at application intervals of 10 and 20 days. The soils were inoculated with pathogenic Pythium spp., known to cause root rot diseases in plants. The soil chemical concentrations were analyzed every ten days, while plant growth parameters (height and leaf numbers) were recorded weekly. A mathematical model describing the fate of Agrifos transformation products was developed and parameterized using this experimental data. The results from the two-month experiment indicated that Agrifos did not enhance plant growth during this period. However, it led to a dramatic increase in soil phosphate (PO₄³⁻) levels, which could pose environmental risks. Despite this, the developed mathematical model demonstrated strong explanatory power, accurately capturing the observed data trends. Consequently, future research should consider integrating this model into broader biogeochemical cycle simulations, particularly those that incorporate chemical transport through soil water. Such integration would support more accurate predictions of the long-term environmental impacts of phosphonate-based products like Agrifos. Full article

The monoculture planting in terraced tea plantations has led to severe soil degradation, which poses a significant threat to the growth of tea plants. However, the mechanisms by which intercropping systems improve soil health through the regulation of soil microbial communities at the micro-topographical scale of terraced tea plantations (i.e., terrace surface, inter-row, and terrace wall) remain unclear. This study investigates the effects of intercropping Ophiopogon japonicus in a five-year tea plantation on the soil physicochemical properties, enzyme activities, and microbial community structure and functions across different micro-topographical features of terraced tea plantations in Wuyi Mountain. The results indicate that intercropping significantly improved the soil organic matter, available nutrients, and redox enzyme activities in the inter-row, terrace surface, and terrace wall, with the effects gradually decreasing with increasing distance from the tea plant rhizosphere. In the intercropping group, tea leaf yield increased by 13.17% (fresh weight) and 19.29% (dry weight) compared to monoculture, and the disease indices of new and old leaves decreased by 40.63% and 38.7%, respectively. Intercropping strengthened the modularity of bacterial networks and the role of stochasticity in shaping bacterial communities in different micro-topographic environments, in contrast to the patterns observed in fungal communities. The importance of microbial phyla such as Proteobacteria and Ascomycota in different micro-topographical features was significantly regulated by intercropping. In different micro-topographical zones of the terraced tea plantation, beneficial bacterial genera such as Sinomonas, Arthrobacter, and Ferruginibacter were significantly enriched, whereas potential fungal pathogens like Nigrospora, Microdochium, and Periconia were markedly suppressed. Functional annotations revealed that nitrogen cycling functions were particularly enhanced in inter-row soils, while carbon cycling functions were more prominent on the terrace surface and wall. This study sheds light on the synergistic regulatory mechanisms between micro-topographical heterogeneity and intercropping systems, offering theoretical support for mitigating soil degradation and optimizing management strategies in terraced tea agroecosystems. Full article

Zizania latifolia (Jiaobai) is an economically important aquatic crop characterized by unique gall formation through interaction with the smut fungus Ustilago esculenta. Understanding factors influencing this interaction is crucial for cultivation. This study investigates the non-target effects of the fungicide Fenaminosulf (FM) on Z. latifolia’s growth, physiology, and underlying molecular pathways. We demonstrate that FM exerts striking concentration-dependent effects, revealing its potential as a modulator of plant development and symbiosis. Physiological measurements showed that a moderate FM concentration (1.25 g/L) promoted key vegetative growth parameters, including plant height and leaf length, while maintaining chlorophyll content, suggesting a potential bio-stimulant effect. In contrast, higher FM concentrations (2.5 g/L and 5 g/L) inhibited vegetative growth but significantly enhanced gall formation, particularly at 2.5 g/L, indicating that FM can redirect plant resources or alter susceptibility to favor the fungal interaction under specific conditions. Transcriptomic analysis provided mechanistic insights, revealing extensive gene expression reprogramming, especially under high FM treatment (5 g/L). Key pathways related to plant-pathogen interaction, phenylpropanoid biosynthesis, and hormone signal transduction were significantly modulated. Notably, FM treatment suppressed key immune-related genes, including Xa21 and PBL19, potentially reducing plant resistance and facilitating gall formation. Hormone signaling analysis revealed inhibition of auxin, cytokinin, brassinosteroid, and jasmonic acid metabolism, indicating a comprehensive molecular recalibration of plant developmental processes. The study provides novel insights into the molecular mechanisms by which FM influences Z. latifolia growth and gall formation. The concentration-dependent effects of FM suggest its potential as a strategic tool for agricultural management, offering a nuanced approach to crop development. These findings contribute to understanding plant-chemical interactions and provide valuable directions for optimizing Z. latifolia cultivation strategies. Full article

Tomato is a widely cultivated vegetable crop worldwide. It is susceptible to various phytopathogens, including fungi, bacteria, viruses, and nematodes. In 2024, an unknown leaf spot disease outbreak, characterized by distinct brown necrotic lesions on leaves, was observed in tomato plants in Yunnan Province, China. Through rigorous pathogen isolation and the fulfillment of Koch’s postulates, it was proved that the fungal isolate could infect tomato leaves and cause typical symptoms. The pathogen isolated from tomato leaves was identified as Nigrospora oryzae based on its morphology and using a multilocus sequence analysis method with the internal transcribed spacer gene (ITS1), beta-tubulin gene (TUB2), and translation elongation factor 1-alpha gene (TEF1-α). This represents the first documented case of N. oryzae infecting tomatoes in the world. Given the damage caused by N. oryzae to tomato plants, we explored biocontrol methods. Through a dual-culture assay on PDA plates, Bacillus velezensis B31 demonstrated significant biocontrol potential, exhibiting strong antagonistic activity toward N. oryzae. In addition, we developed a polyethylene glycol (PEG)-mediated transformation system that successfully introduced pYF11-GFP into the protoplasts of N. oryzae. This achievement provides a foundation for future genetic manipulation studies of N. oryzae. Full article

Litter decomposition dynamics are largely governed by microbial interactions. While the involvement of endophytic fungi in early-stage decomposition and microbial succession is well established, their species-specific contributions to decomposer community assembly remain insufficiently understood. This study investigated the effects of single-strain endophytic colonization using dominant species (Tubakia dryina, Tubakia dryinoides, Guignardia sp.) and rare species (Neofusicoccum parvum, Penicillium citrinum) on Quercus acutissima leaf decomposition through a controlled field experiment in a karst ecosystem. Endophytes accelerated decomposition rates across treatments but paradoxically reduced transient CO₂ emissions, linked to intensified microbial carbon and phosphorus limitations in late stages. Contrary to expectations, decomposition efficiency was governed by endophytic fungal species traits rather than colonization abundance, with rare species outperforming dominant taxa. Endophytes induced significant fungal community restructuring, reducing Ascomycota while enriching lignin-degrading Basidiomycota, but minimally affected bacterial composition. Co-occurrence networks revealed endophyte-driven fragmentation of microbial connectivity, with only two keystone fungal hubs (Trechispora sp. and Russula carmesina) identified compared to natural communities. Endophytic colonization improved fungal community assembly, mediated by an increase in lignin-degrading Basidiomycota and the suppression of pathogenic Leotiomycetes lineages. Our findings demonstrate that endophytes hierarchically regulate decomposer communities through phylogenetically conserved fungal interactions, prioritizing functional trait selection over competitive dominance, thereby stabilizing decomposition under nutrient constraints. This mechanistic framework advances predictions of litter decay dynamics in forest ecosystems undergoing microbial community perturbations. Full article

Stemphylium lycopersici is the causal pathogen of the devastating tomato gray leaf spot with a wide range of alternative plant hosts. To mitigate its potential endemic in facility-cultivated tomatoes, novel disease control strategies should be attempted to minimize the use of chemical fungicides. In this study, we identified a metalloprotease from S. lycopersici genome and designated it as SlMEP1, as it appears to be a typical zinc metalloproteinase containing a WLM (WSS1-like metalloprotease) domain and a characteristic HEXXH motif, which we determined by analyzing its transcriptional profile and enzymatic functions. The transcription level of SlMEP1 increased greatly during the fungal invasion of tomato leaves. The deletion of the SlMEP1 gene from S. lycopersici hindered its mycelial growth and reduced its pathogenicity. An assessment of the functional dissection indicated that SlMEP1 induced cell collapse and inhibited the expression of the host chitinases, which consequently made tomato cells more susceptible to S. lycopersici and other pathogenic fungi. Full article

Fusarium infections in Pisum sativum L. crops present a major constraint to cultivation, leading to substantial yield losses. However, effective disease management strategies, particularly the implementation of biological control methods, offer promising approaches for mitigating infection severity and limiting pathogen spread. In P. sativum cultivation, pathogen control is particularly challenging due to the limited penetration of pesticides into the leaves. This is attributed to the dense crystalline plate structure within the leaf cuticle, which acts as a barrier, reducing the efficacy of conventional chemical treatments. Therefore, optimizing the formulation of biopesticides and plant conditioning agents is essential to improve the absorption and bioavailability of active ingredients, ensuring more effective disease management in P. sativum cultivation. This study examined the exogenous effects of garlic extracts in different formulations, including EliceVakcina (liposomal formulation), Garlic-lipo (liposomal formulation), and Garlic-oil (oil-based formulation), which contained high concentrations of abscisic acid (ABA) at 6.3, 81, and 80.4 µg g⁻¹, respectively. Transcriptomic profiling, including the identification of Differentially expressed genes (DEGs) and KEGG pathway analysis of EliceVakcina-treated field samples, revealed a significant upregulation of stress- and defence-related genes, as well as pathways associated with thiamine metabolism and ABA signalling. Notably, key defence genes, including pathogenesis-related (PR1, PR2, PR4, PR5) and SnRK2, were overexpressed, indicating an enhanced stress response. HPLC-DAD analytical investigations confirmed the activation of the thiamine biosynthesis pathway, demonstrating a 14.3% increase in vitamin B1 content. Furthermore, the absence of Fusarium infection in the treated small-plot field cultures suggests that the tested garlic extracts formulation functions as a promising preventive biostimulant against plant fungal diseases. Full article

Peach palm (Bactris gasipaes Kunth) is a long-lived tropical palm valued for its edible, nutritious fruits. The cultivation area of peach palm, which was introduced to Thailand for fruit production, has been steadily expanding. Small brown spots that expanded into irregular lesions with dark margins were first observed on B. gasipaes seedlings in commercial nurseries in Phetchaburi Province, southern Thailand. To identify the causal pathogens, ten fungal isolates were obtained from symptomatic leaves and subjected to pathogenicity tests, confirming their ability to cause the disease. Morphological and molecular analyses identified five isolates as Colletotrichum fructicola (BGC02.2, BGC03) and C. theobromicola (BGC01, BGC02.1, BGC04) and five isolates as Fusarium pernambucanum (BGF01, BGF02, BGF03, BGF04.1, BGF04.2). Phylogenetic analysis was based on act, cal, gapdh, ITS, and tub2 regions for Colletotrichum spp. and cal, rpb2, and tef1-α for Fusarium spp. In vitro fungicide assays revealed that C. fructicola and C. theobromicola were the most sensitive to carbendazim, mancozeb, and prochloraz, while F. pernambucanum was effectively inhibited by mancozeb and prochloraz. This study represents the first report of C. fructicola, C. theobromicola, and F. pernambucanum causing leaf spot disease on B. gasipaes in Thailand, providing essential insights for disease management strategies in the region. Full article

In recent years, Castanopsis carlesii, a keystone species in southern China’s forest ecosystems with high ecological and economic importance, has faced growing challenges from severe nut rot diseases. Gnomoniopsis (Gnomoniaceae, Diaporthales, Sordariomycetes, Ascomycota) represents a significant fungal genus that causes leaf spots, branch cankers, and fruit rot diseases. In this study, rotten nuts of C. carlesii were collected from Fujian Province, and fungal isolates were obtained using the tissue isolation method. Morphological characterization and molecular phylogenetic analysis, based on the combined sequences of the internal transcribed spacer region of rDNA (ITS), the translation elongation factor 1-alpha (tef1) gene, and the partial beta-tubulin (tub2) gene were used to identify these isolates. As a result, new isolates from diseased nuts of C. carlesii formed a distinct clade with Gnomoniopsis, and morphologically differentiated from the other species; hence, G. flava sp. nov. is proposed herein. Furthermore, pathogenicity tests involving three isolates of G. flava were conducted on healthy nuts of C. carlesii, confirming its role as the causal agent of this new plant disease. This study not only advances our understanding of species diversity within Gnomoniopsis but also lays the groundwork for developing control strategies for C. carlesii nut rot disease. Full article

Bacillus thuringiensis (Bt) is widely recognized as the most important microbial pesticide controlling various insect pests and diseases due to its insecticidal crystal proteins (ICPs) and antimicrobial metabolites. The current study investigates the biocontrol potential of B. thuringiensis GBAC46 against the fungal pathogen Fusarium verticillioides and the insect pest Spodoptera frugiperda through multiple mechanisms. Phenotypic experiments revealed that GBAC46 effectively inhibited F. verticillioides growth by inducing reactive oxygen species (ROS) accumulation and showed enhanced larvicidal activity against second instar S. frugiperda larvae. Pot experiments showed that feeding by S. frugiperda enhanced F. verticillioides infection in maize. The Bt strain GBAC46 effectively controlled both pests and diseases in greenhouse maize seedlings. Applying the Bt strain GBAC46 reduced feeding damage from S. frugiperda, decreased leaf yellowing and wilting caused by F. verticillioides, and improved growth indicators such as plant height, fresh weight, and dry weight. RT-qPCR results revealed that the Bt strain GBAC46 induced key defense genes in maize involved in activating salicylic acid, jasmonic acid, and ethylene pathways. The overall study demonstrated and confirmed the GBAC46 strain as a promising microbial agent for disease and pest management. Full article