Search Results (65)

Villosiclava virens (anamorph: Ustilaginoidea virens), the causal fungal pathogen of rice false smut, has been found to produce various secondary metabolites. The albino strain LN02 is a natural albino phenotype mutant of V. virens due to its inability to produce ustilaginoidins. The fermentation of V. virens LN02 was performed in solid rice medium to obtain fungal cultures, which were chemically investigated. After removing the known metabolites, two new dimeric sorbicillinoids, namely ustisorbicillinols G (1) and H (2), were isolated from the ethyl acetate extract. Their structures were elucidated using spectroscopic data analyses and quantum chemical calculations. Compounds 1 and 2 displayed antibacterial activity towards Ralstonia solanacearum, Agrobacterium tumefaciens and Bacillus subtilis, with median inhibitory concentration (IC₅₀) values of 19.76–25.43 μg/mL for 1 and 25.35–45.48 μg/mL for 2. The discovery of new sorbicillinoids will increase the diversity of the secondary metabolites of V. virens and provide candidates for the creation of new antimicrobials as well. Full article

Significant wastes such as bagasse, molasses, and vinasses are produced during sugarcane processing. Due to their high sugar content, these wastes are commonly used as low-cost substrates for biofuel production. However, these substrates are also suitable for the microbial synthesis of high-value biochemicals like biosurfactants. Sporisorium scitamineum, a smut fungus capable of growing on sugarcane residues and producing mannosylerythritol lipids (MELs) and cellobiose lipids (CBLs), was identified as a promising candidate for valorizing sugarcane wastes. This study investigated MEL and CBL co-production from pure sugars and sugarcane molasses using an S. scitamineum strain isolated from sugarcane residues originating from KwaZulu-Natal, South Africa. Among the sugars tested, sucrose supported the highest glycolipid production, yielding 0.24 g/L MELs and 2.73 g/L CBLs. Lower titers were achieved with fructose, and no production occurred with glucose. Sugarcane molasses also proved to be an effective substrate, yielding 1.46 g/L CBLs—the highest reported titer from an industrial waste to date. However, all titers remained far below those of other glycolipids, which consistently exceed 50 g/L. Future efforts should focus on enhancing CBL production through process optimization or genetic engineering. 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

Ustiloxins are a kind of cyclopeptide mycotoxins produced by rice false smut pathogen Villosiclava virens, which seriously threatens the safe production of rice and health of humans and animals. Hydroxylation, a biotransformation reaction that regio- and stereoselectively introduces a hydroxyl group into the molecule catalyzed by the hydroxylase produced by organisms, has been considered an efficient way to detoxify mycotoxins. In this study, the endophytic fungus Petriella setifera Nitaf10 was found to be able to detoxify ustiloxin A, the main toxic component in V. virens. In addition to the two main transformed products previously identified, ustiloxins A1 and A2, an additional transformed product was obtained by using cell-free extract (CFE) of P. setifera Nitaf10 prepared with 5 mmol/L of pH 9.0 carbonate-buffered solution (CBS). It was structurally characterized as a novel ustiloxin analog named 13-hydroxy ustiloxin A (1) by analysis of the 1D and 2D NMR and HRESIMS spectra as well as by comparison with known ustiloxins. Biotransformation reaction of ustiloxin A was found to proceed via hydroxylation, and was possibly catalyzed by the intracellular hydroxylase in the CFE. The cytotoxic and phytotoxic activities of 13-hydroxy ustiloxin A (1) were much weaker than those of ustiloxin A. Detoxification of ustiloxin A by hydroxylation of P. setifera will be an efficient strategy. Full article

The cyanogenic glucoside dhurrin is found in sorghum and has been reported for its role in defense against biotic and abiotic stresses, both involving hydrogen cyanide (HCN) release. The fungus Sporisorium reilianum f. sp. reilianum (SRS) causes sorghum head smut and the infection occurs at the seedling stage, later resulting in panicle loss. Here, the focus was to determine the role of dhurrin in sorghum’s reaction against SRS infection. We investigated the genomic basis of HCN potential (HCNp) variation and its relationship with seedlings’ response to SRS inoculation, along with other sorghum traits, and the expression of dhurrin biosynthetic genes in SRS-inoculated young sorghum. Genome-wide association studies (GWAS) using HCNp scores showed significant single nucleotide polymorphisms (SNPs) on chromosomes harboring the dhurrin biosynthetic and catabolic genes but not in proximity. Significant hits were also detected in or near genes encoding proteins involved in plant defense/resistance against biotic stresses. Correlation analyses showed a strong positive relationship between average HCNp scores and latent period in SRS-inoculated sorghum seedlings. RT-qPCR revealed that the dhurrin biosynthetic genes were upregulated in the leaves of the head smut resistant line BTx635 up to two days after SRS inoculation. Our results suggest the involvement of dhurrin in sorghum’s protection against SRS. Full article

Fungal spore calendars for Mexico are non-existent. This research represents the first fungal spore concentration data in the atmosphere of Hermosillo, Mexico, a city in the Sonoran Desert with high rates of allergies and public health problems. We used standardized sampling techniques frequently used by aerobiologists, including a Burkard spore trap to monitor airborne fungal spores daily for 2016–2019 and 2022–2023. Results are expressed as daily fungal spore concentrations in air (spores/m³ air). The most common fungal outdoor spores corresponded to Cladosporium (44%), Ascospora (17%), Smut (14%), Alternaria (12%), and Diatrypaceae (7%) of the total 6-year data. High minimum temperatures produce an increase in the most important spores in the air (Cladosporium and Alternaria), whereas precipitation increases Ascospore concentrations. The most important peak of fungal spore concentration in the air is recorded during summer–fall in all cases. Airborne fungal spores at Hermosillo had a greater impact on human health. These data will be of great help for the prevention, diagnostics, and treatment of seasonal allergies in the population and for the agricultural sector that has problems with some pathogens of their crops caused by fungus. Full article

The biotrophic fungus Ustilago maydis, which causes smut disease in maize, secretes numerous proteins upon plant colonization. Some of them, termed effectors, help to evade plant defenses and manipulate cellular processes within the host. The function of many proteins specifically secreted during infection remains elusive. In this study, we biochemically characterized one such protein, UMAG_00027, that is highly expressed during plant infection. We show that UMAG_00027 is a secreted protein with a lectin-like fold and therefore term it Llp1 (lectin-like-protein 1). Llp1 decorated the fungal cell wall of cells grown in axenic culture or proliferating in planta, which is in agreement with its potential sugar-binding ability. We were unable to identify the precise sugar moieties that are bound by Llp1. CRISPR/Cas9-mediated deletion of llp1 reveals that the gene is not essential for fungal virulence. A structural search shows the presence of several other lectin-like proteins in U. maydis that might compensate for the function of Llp1 in ∆llp1 mutants. We therefore speculate that Llp1 is part of a family of lectin-like proteins with redundant functions. Full article

Sugarcane is one of the most economically important crops, particularly in Brazil, which is the largest sugarcane producer globally. Sugarcane smut, caused by the fungus Sporisorium scitamineum (Syd.), is a major disease of this crop. This study investigated the response of 165 sugarcane genotypes to smut infection under greenhouse conditions using the needle-bud puncture method. The disease incidence, the Area Under the Disease Progress Curve (AUDPC), and the relative Area Under the Disease Progress Curve (rAUDPC) were calculated, along with broad-sense heritability (h²) and the genotype’s effects. Spearman’s correlation coefficient (r²) was used to determine the correlation between the number of corresponding genotypes with smut incidence in both the greenhouse and the field. The incidence of smut ranged from 0% to 88%, and AUDPC values varied from 0 to 500 for 131 of the 165 genotypes. Based on the rAUDPC, 54 genotypes were classified as highly resistant. The correlation between greenhouse and field disease expression was positive and moderately strong (r² = 61%), and the h² value in greenhouse conditions was 74%. The needle-bud puncture method combined with the rAUDPC values was promising for identifying susceptible genotypes and highlighting potential smut-resistant genotypes. Full article

Rice false smut (RFS), an emerging disease caused by the fungus Ustilaginoidea virens (Cooke), reduces rice grain yield and quality in rice-planting regions worldwide. The identification of the genes or quantitative trait loci (QTLs) associated with RFS resistance is vital to resistance breeding and the mitigation of RFS damage. In this study, RFS resistance QTLs were located in the resistant variety IR77298-14-1-2::IRGC117374-1. A total of 4 RFS resistance QTLs were detected on rice chromosomes 1, 3, 5, and 12 in the F₂ and F₄ mapping populations using 119 polymorphic simple sequence repeat (SSR) molecular markers. Of these QTLs, qRFS3.01 and qRFS12.01-1 were repeatedly detected in both populations. Interestingly, QTL qRFS3.01 on chromosome 3 is a novel resistance locus that exhibited the largest phenotypic effect. These results suggest that SSR markers linked to qRFS3.01 are valuable for marker-assisted breeding for RFS resistance in rice. The prediction of putative candidate genes within qRFS3.01 revealed three resistance-related proteins containing an F-box domain, Myb-like DNA-binding domain, and kinase protein. In summary, our findings provide new QTLs/genes for resistance to RFS and will promote rice disease resistance through molecular-marker-assisted breeding. Full article

Ustiloxins are a group of cyclopeptide mycotoxins produced by rice false smut pathogen Villosiclava virens (anamorph: Ustilaginoidea virens) which seriously threaten the safety production of rice and the health of humans and livestock. Ustiloxin A, accounting for 60% of the total ustiloxins, is the main toxic component. Biotransformation, a process of modifying the functional groups of compounds by means of regio- or stereo-specific reactions catalyzed by the enzymes produced by organisms, has been considered as an efficient way to detoxify mycotoxins. In this study, the endophytic fungus Petriella setifera Nitaf10 was found to be able to detoxify ustiloxin A through biotransformation. Two transformed products were obtained by using the cell-free extract (CFE) containing intracellular enzymes of P. setifera Nitaf10. They were structurally characterized as novel ustiloxin analogs named ustiloxins A1 (1) and A2 (2) by analysis of the 1D and 2D NMR and HRESIMS spectra as well as by comparison with known ustiloxins. The cytotoxic activity of ustiloxins A1 (1) and A2 (2) was much weaker than that of ustiloxin A. The biotransformation of ustiloxin A was found to proceed via oxidative deamination and decarboxylation and was possibly catalyzed by the intracellular amine oxidase and oxidative decarboxylase in the CFE. An appropriate bioconversion was achieved by incubating ustiloxin A with the CFE prepared in 0.5 mol/L phosphate buffer (pH 7.0) for 24 to 48 h. The optimum initial pH values for the bioconversion of ustiloxin A were 7–9. Among eight metal ions (Co²⁺, Cu²⁺, Fe³⁺, Zn²⁺, Ba²⁺, Ca²⁺, Mg²⁺ and Mn²⁺) tested at 5 mmol/L, Cu²⁺, Fe³⁺ and Zn²⁺ totally inhibited the conversion of ustiloxin A. In conclusion, detoxification of ustiloxin A through oxidative deamination and decarboxylation is an efficient strategy. Full article

Anthracocystis panici-leucophaei, causal agent of smut on Digitaria insularis (sourgrass), was evaluated as a biological control agent for this weed. Two types of inocula (teliospore and sporidia) were tested to assess its infectivity. The effects of teliospore and sporidia inoculations at different phenological stages of sourgrass were compared, as well as the potential of sporidia and teliospores in post-emergence sourgrass management. Virulence tests were conducted with the isolates obtained from D. insularis and evaluation of specificity of A. panici-leucophaei. Both teliospores and sporidia of A. panici-leucophaei are infective to D. insularis in three different phenological stages. Newly emerged plants with one pair of leaves are more sensitive to A. panici-leucophaei. Infection by A. panici-leucophaei inhibits the growth of sourgrass, decreasing several physiological parameters of D. insularis plants. The fungus produces systematic infection of sourgrass plants and may induce the formation of sori in a significant proportion of the plant panicles, partly castrating those plants. Among sixteen A. panici-peucophaei isolates tested, isolate 46 was the most virulent and inhibited the growth of sourgrass plants, and thus appears to have good potential as a biological control agent to be deployed against sourgrass. A. panici-leucophaei was demonstrated to be specific to D. insularis. Full article

In the future, the cultivation of maize will become more and more prominent. As the world’s demand for food and animal feeding increases, remote sensing technologies (RS technologies), especially unmanned aerial vehicles (UAVs), are developing more and more, and the usability of the cameras (Multispectral-MS) installed on them is increasing, especially for plant disease detection and severity observations. In the present research, two different maize hybrids, P9025 and sweet corn Dessert R78 (CS hybrid), were employed. Four different treatments were performed with three different doses (low, medium, and high dosage) of infection with corn smut fungus (Ustilago maydis [DC] Corda). The fields were monitored two times after the inoculation—20 DAI (days after inoculation) and 27 DAI. The orthomosaics were created in WebODM 2.5.2 software and the study included five vegetation indices (NDVI [Normalized Difference Vegetation Index], GNDVI [Green Normalized Difference Vegetation Index], NDRE [Normalized Difference Red Edge], LCI [Leaf Chlorophyll Index] and ENDVI [Enhanced Normalized Difference Vegetation Index]) with further analysis in QGIS. The gathered data were analyzed using R-based Jamovi 2.6.13 software with different statistical methods. In the case of the sweet maize hybrid, we obtained promising results, as follows: the NDVI values of CS 0 were significantly higher than the high-dosed infection CS 10.000 with a mean difference of 0.05422 *** and a p value of 4.43 × 10⁻⁵ value, suggesting differences in all of the levels of infection. Furthermore, we investigated the correlations of the vegetation indices (VI) for the Dessert R78, where NDVI and GNDVI showed high correlations. NDVI had a strong correlation with GNDVI (r = 0.83), a medium correlation with LCI (r = 0.56) and a weak correlation with NDRE (r = 0.419). There was also a strong correlation between LCI and GNDVI, with r = 0.836. NDRE and GNDVI indices had the correlation coefficients with a CCoeff. of r = 0.716. For hybrid separation analyses, useful results were obtained for NDVI and ENDVI as well. Full article

Ustilago crameri is a pathogenic basidiomycete fungus that causes foxtail millet kernel smut (FMKS), a devastating grain disease in most foxtail millet growing regions of the world. Carbohydrate-Binding Modules (CBMs) are one of the important families of carbohydrate-active enzymes (CAZymes) in fungi and play a crucial role in fungal growth and development, as well as in pathogen infection. However, there is little information about the CBM family in U. crameri. Here, 11 CBM members were identified based on complete sequence analysis and functional annotation of the genome of U. crameri. According to phylogenetic analysis, they were divided into six groups. Gene structure and sequence composition analysis showed that these 11 UcCBM genes exhibit differences in gene structure and protein motifs. Furthermore, several cis-regulatory elements involved in plant hormones were detected in the promoter regions of these UcCBM genes. Gene ontology (GO) enrichment and protein–protein interaction (PPI) analysis showed that UcCBM proteins were involved in carbohydrate metabolism, and multiple partner protein interactions with UcCBM were also detected. The expression of UcCBM genes during U. crameri infection is further clarified, and the results indicate that several UcCBM genes were induced by U. crameri infection. These results provide valuable information for elucidating the features of U. crameri CBMs’ family proteins and lay a crucial foundation for further research into their roles in interactions between U. crameri and foxtail millet. Full article

Sugarcane smut, a serious disease caused by the fungus Sporosorium scitamineum, can result in 30% to 100% cane loss. The most affordable and efficient measure of preventing and handling sugarcane smut disease is to select disease-resistant varieties. A comprehensive evaluation of disease resistance based on the incidence of smut disease is essential during the selection process, necessitating the rapid and accurate identification of sugarcane smut. Traditional identification methods, which rely on visual observation of symptoms, are time-consuming, costly, and inefficient. To address these limitations, we present the lightweight sugarcane smut detection model (YOLOv5s-ECCW), which incorporates several innovative features. Specifically, the EfficientNetV2 is incorporated into the YOLOv5 network to achieve model compression while maintaining high detection accuracy. The convolutional block attention mechanism (CBAM) is added to the backbone network to improve its feature extraction capability and suppress irrelevant information. The C3STR module is used to replace the C3 module, enhancing the ability to capture global large targets. The WIoU loss function is used in place of the CIoU one to improve the bounding box regression’s accuracy. The experimental results demonstrate that the YOLOv5s-ECCW model achieves a mean average precision (mAP) of 97.8% with only 4.9 G FLOPs and 3.25 M parameters. Compared with the original YOLOv5, our improvements include a 0.2% increase in mAP, a 54% reduction in parameters, and a 70.3% decrease in computational requirements. The proposed model outperforms YOLOv4, SSD, YOLOv5, and YOLOv8 in terms of accuracy, efficiency, and model size. The YOLOv5s-ECCW model meets the urgent need for the accurate real-time identification of sugarcane smut, supporting better disease management and selection of resistant varieties. Full article

Rice kernel smut caused by the biotrophic basidiomycete fungus Tilletia horrida causes significant yield losses in hybrid rice-growing areas around the world. Cytochrome P450 (CYP) enzyme is a membrane-bound heme-containing monooxygenase. In fungi, CYPs play a role in cellular metabolism, adaptation, pathogenicity, decomposition, and biotransformation of hazardous chemicals. In this study, we identified 20 CYP genes based on complete sequence analysis and functional annotation from the T. horrida JY-521 genome. The subcellular localization, conserved motifs, and structures of these 20 CYP genes were further predicted. The ThCYP genes exhibit differences in gene structures and protein motifs. Subcellular localization showed that they were located in the plasma membrane, cytoplasm, nucleus, mitochondria, and extracellular space, indicating that they had multiple functions. Some cis-regulatory elements related to stress response and plant hormones were found in the promoter regions of these genes. Protein–protein interaction (PPI) analysis showed that several ThCYP proteins interact with multiple proteins involved in the ergosterol pathway. Moreover, the expression of 20 CYP genes had different responses to different infection time points and underwent dynamic changes during T. horrida JY-521 infection, indicating that these genes were involved in the interaction with rice and their potential role in the pathogenic mechanism. These results provided valuable resources for elucidating the structure of T. horrida CYP family proteins and laid an important foundation for further research of their roles in the pathogenesis. Full article