Search Results (103)

Plant pathogens pose a severe threat to global agricultural production, and their pathogenicity is closely linked to the biosynthesis of secondary metabolites. Basidiomycete within the family Ustilaginaceae represent significant plant pathogens, among which Ustilago maydis, as a model species, has been extensively studied for its secondary metabolites. However, the biosynthetic potential of other species within this family remains poorly understood. In this study, we conducted whole-genome bioinformatic analyses of 16 Ustilaginaceae species, including U. maydis, to systematically identify the distribution of biosynthetic gene clusters (BGCs), core gene domain compositions, and interspecies similarities. A total of 181 predicted BGCs were identified, averaging approximately 11 per species. BGCs for mannosylerythritol lipids (MELs), siderophores, and itaconic acid, as well as the melanin-associated genes pks1 and pks2, were widely distributed across most species. Conversely, an additional melanin biosynthetic gene cluster was found exclusively in U. maydis strain 521, indicating species-specific occurrence. Furthermore, this study identified a novel class of polyketide synthase (PKS) gene clusters with uncharacterized functions across 15 species, exhibiting high sequence and structural conservation between species. These findings reveal the rich metabolic diversity and species-specific biosynthetic potential of Ustilaginaceae, and by using U. maydis as a reference model, we highlight several BGCs (e.g., for MELs, siderophores, itaconic acid, and melanin) that are known to contribute to virulence or pathogenicity in plant hosts. This provides new insights into their pathogenic mechanisms. Full article

To explore the appropriate supplementation rate of yeast culture (YC) in Kazakh sheep during fattening, the effects of different YC supplementation rates on rumen fermentation parameters and microbial community were studied through in vitro rumen fluid fermentation experiments. A 0.40 g high-concentrate diet was used as the fermentation substrate, and five groups were added with YC at 0% (CK), 1.25% (YC1), 2.5% (YC2), 3.75% (YC3) and 5% (YC4) of dietary dry matter, respectively. Anaerobic fermentation was carried out for 48 h in 60 mL fermentation broth. The results showed that the 48 h GP and microbial crude protein (MCP) concentration in all YC supplementation groups were significantly higher than those in the CK group (p < 0.05). The concentrations of total volatile fatty acids (TVFA) and propionate in the YC1 and YC2 groups were significantly increased and the A/P ratio in the two groups was significantly decreased (p < 0.05). The Multi-factor Comprehensive Evaluation Index (MFAEI) calculation indicated that 1.25% was appropriate. The YC1 and YC2 groups significantly increased the richness and diversity of rumen bacterial communities (Chao1 and Shannon indices, p < 0.05), and significantly increased the relative abundance of Bacteroidota and NK4A214_group (p < 0.05), while significantly decreasing the relative abundance of the potential pathogenic bacterium Campylobacter (p < 0.05). Ustilago abundance was significantly suppressed in all the YC-supplemented groups (p < 0.05). The most effective YC supplementation rate among the tested doses was 1.25% according to the MFAEI and key microbial indicators. The results suggest that dietary supplementation of 1.25% YC (dry matter basis) may beneficially modulate rumen fermentation parameters under in vitro conditions, providing a reference for further in vivo studies on its application in fattening Kazakh sheep. Full article

To cope with the increasing pressure from diseases and pests under climate change, the effect of 6 maize sowing dates on the plant health of an ultra-early maize variety (Pyroxenia, FAO 130) was analyzed in studies conducted from 2016 to 2018. The assessment of the response of the ultra-early variety to climate change will contribute to the identification of its predisposition to cultivation in terms of health recognition. The extent of plant damage caused by the frit fly (Oscinella frit L.), the European corn borer (Ostrinia nubilalis Hbn.), and the cereal leaf beetle (Oulema melanopus L.), as well as the severity of plant infection by Fusarium ear rot (Fusarium spp.) and maize smut (Ustilago maydis (D.C.) Corda), was assessed. Air temperature, precipitation, and the length of the growing period at individual sowing dates were also analyzed. The lowest level of insect damage and the highest level of disease infection were recorded in the final year of the study (2018), which was dry and had higher mean air temperature. Precipitation and temperature during the sowing dates ranged between 110.5 and 146.1 mm and 17.5 and 19.9 °C, respectively. The optimal sowing date for reducing maize losses caused by insect pests and diseases was found to be the earliest time points, i.e., between April 12 and 26. Full article

Ustilago maydis is an economically significant biotrophic smut fungus, capable of infecting maize. This is a localized infection where tumors are formed, potentially in any of the aboveground parts of the plant. In extreme cases, maize plants may die. It is also dimorphic, i.e., it is capable of switching from yeast-like to filamentous forms. The switch can be induced by nitrogen sources, pH, and some lipids/oils. The active infectious form is the filamentous form which is capable of penetrating plant cells using the appressorium. This study focuses on understanding the mitochondrial genome diversity in U. maydis, the selection pressure on the genes encoded in the mitochondrial genome, and the phylogeny of the strains investigated. The results suggest that the strains maintained high consistency in genome architecture and synteny. The cox1 and cob genes in the genomes possessed different intron numbers, with the presence or absence of homing endonuclease genes (HEGs), which overall contributed to the differences in the genome sizes. Among the genes in the mitogenome, nad6 was the only gene that has a non-synonymous nucleotide change, but the overall changes within the mitogenomes suggest purifying selection. The study helped identify the different mitotypes using PCR, although further markers or whole-genome sequencing may be required to fully distinguish mitotypes. Full article

Priestia megaterium is a maize endophyte that may help the plant defend itself against bacterial and fungal pathogens. This study aimed to identify antimicrobials produced by two P. megaterium endophytes (FS10 and FS11) from maize and determine if seed coating with either strain could increase resistance to pathogens. Volatiles emitted by both isolates reduced the hyphal growth of fungi by 17–76%. Gas chromatography analysis found that each strain emitted isovaleric acid (IVA) and 3-methyl-1-butanol (3MB). Volatiles produced by each isolate inhibited bacterial growth, especially Clavibacter michiganensis ssp. michiganensis (Cmm). IVA killed all Cmm cells at 208 µL L⁻¹, while 3MB inhibited Cmm growth by 51% at 208 µL L⁻¹. Diluted cell-free extracts from FS10 and FS11 cultures stopped growth of Cmm, Erwinia amylovora and Ustilago maydis but did not arrest growth of Fusarium verticillioides. The treatment of corn seeds with FS10 or FS11 reduced leaf damage by 38–84% in young plants caused by Bipolaris maydis, Colletotrichum graminicola (Ces.) G.W. Wilson 1914, Exserohilum turcicum and Pythium sylvaticum. FS10 and FS11 isolates exuded volatile and soluble compounds that were more effective in slowing growth of bacteria than fungi. It is likely that corn seed treatment with FS10 and FS11 triggers induced systemic resistance, which mitigates leaf damage caused by maize pathogens. Full article

The main objective of this research was to evaluate the effect of extrusion temperature (ET), feed moisture content (FMC), and the proportion of huitlacoche relative to corn starch (HCP/Starch) on the physicochemical, techno-functional, and color properties of an extruded snack, using response surface methodology to optimize processing conditions and product quality. A Box–Behnken design and response surface methodology were used to model and optimize the process. The responses analyzed included residence time (RT), specific mechanical energy (SME), expansion index (EI), bulk density (BD), texture (Tex), water absorption index (WAI), water solubility index (WSI), pH, and color parameters (L*, a*, b*, C*, h°, and ΔE). Results showed that the huitlacoche proportion significantly affected BD, Tex, WSI, and color, while ET and FMC mainly influenced EI, SME, and other techno-functional traits. Multi-response optimization indicated that 150.4 °C, 15.8 g/100 g FMC, and 10–20 g/100 g HCP/Starch maximized EI (2.27) and minimized BD (0.40 g/cm³), Tex (17.5 N), and SME (347.6 J/g). The overall performance was summarized by global desirability (0.83–0.88), a metric that combines all responses into a single scale (0 = poor; 1 = is the most desired goal). The optimized conditions produced snacks with acceptable hydration capacity, pH, and color, supporting huitlacoche as a viable functional ingredient. These findings demonstrate the potential of this traditional resource for developing sustainable, value-added, and health-oriented extruded foods. Full article

Corn smut, caused by Ustilago maydis, significantly threatens maize production. This study evaluated 199 maize inbred lines at the seedling stage under greenhouse conditions for resistance to U. maydis, identifying 39 highly resistant lines. A genome-wide association study (GWAS) using the mrMLM model detected 19 significant single-nucleotide polymorphism (SNP) loci. Based on a linkage disequilibrium (LD) decay distance of 260 kb, 226 candidate genes were identified. Utilizing the significant loci chr1_244281660 and chr5_220156746, two kompetitive allele-specific PCR (KASP) markers were successfully developed. A PCR-based sequence-specific oligonucleotide probe hybridization technique applied to the 199 experimental lines and 60 validation lines confirmed polymorphism for both markers, with selection efficiencies of 48.12% and 43.33%, respectively. The tested materials were derived from foundational inbred lines of domestic and foreign origin. Analysis of 39 highly resistant lines showed that the advantageous alleles carrying thymine/cytosine (T/C) predominated at frequencies of 94.87% and 53.84%, respectively. The genotype TTCC conferred high resistance, while CCTT was highly susceptible. The resistance exhibited high heritability and significant gene-by-environment interaction. This work systematically dissects the genetic basis of common smut resistance in maize, identifies favorable alleles, and provides a novel KASP marker-based strategy for developing disease-resistant germplasm. Full article

Mannosyl erythritol lipids (MELs) are glycolipid biosurfactants produced by Ustilaginomycete yeasts. The MEL biosynthetic pathway has been characterized in Ustilago maydis where a putative transporter encoded by MMF1 is required for the secretion of the glycolipid surfactant to the extracellular space. The anamorphic yeast Moesziomyces antarcticus is a prolific producer of MELs, but the mechanism of MEL secretion is less well characterized than in U. maydis. Homologous recombination was employed to generate a disruption of the MMF1 gene in M. antarcticus JCM10317. This mutation did not prevent the intracellular accumulation of MEL species but did result in significantly reduced secretion of the conventional MEL-A, MEL-B and MEL-C species detectable by thin-layer chromatography. However, the mutant strain did secrete a glycolipid species that is distinct from conventional MEL-A/B/C and similar to a glycolipid secreted by MMF1 mutant strains of U. maydis and Pseudozyma tsukubaensis. Despite the defect in MEL secretion displayed by the M. antarcticus strain harbouring a disrupted MMF1 gene, these cells did not display a significant defect in growth or cell morphology. The findings of this investigation provide evidence that M. antarcticus MMF1 encodes a transporter required for the secretion of MELs but not required for MEL synthesis or cell growth. 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

Fungi produce dormant structures that are responsible for protection during adverse environmental conditions and dispersal (disease spread). Ustilago maydis, a basidiomycete plant pathogen, is a model for understanding the molecular mechanisms of teliospore dormancy and germination. Dormant teliospores store components required for germination including mRNAs which may be stored as dsRNAs. RNA helicases are conserved enzymes that function to modulate, bind, and unwind RNA duplexes, and can displace other proteins. We hypothesize that RNA helicases function during teliospore dormancy to stabilize and/or modulate stored mRNAs. We identified the U. maydis udbp3 and uded1 as encoding RNA helicases of interest as they are upregulated in the dormant teliospore and decrease during germination. Experimental results suggest that udbp3 may function as a negative regulator of osmotic stress-responsive genes and that uded1 modulates stress response by repressing translation. The altered expression of uded1 also results in slow growth, polarized growth, and the formation of dsRNA. Together, the data support a role for both helicases modulating gene expression, in response to stress, leading to teliospore dormancy and also modulating responses for teliospore germination. Increasing our molecular understanding of these processes will aid in developing novel strategies to mitigate disease spread. 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

Food security has been an essential priority for decades due to its direct impact on human development. Despite significant advances in meeting basic food needs, food security remains a global challenge. In Mexico, the sustainable traditional polyculture system known as milpa allows synergy among three or more food sources, increasing the economic income for peasants. We integrated the controlled production of huitlacoche (Ustilago maydis + Zea mays) galls, traditional food consumed since pre-Hispanic times, in a milpa from Las Ánimas community, Tecoanapa Municipality, Guerrero, Mexico, in order to improve food diversity, productivity, income, and food security. Two contiguous plots were evaluated: the traditional milpa system (TMS) and the milpa integrating controlled production of huitlacoche galls (TMS + Huitlacoche). Different variables were assessed including weight and size of maize ears and huitlacoche galls; degree of huitlacoche infection; production and income of maize (Zea mays), beans (Phaseolus spp.), squash (Cucurbita spp.), and huitlacoche; and sustainability indicators, maize grain sales, type of maize seed, huitlacoche sales, beans sales, and squash sales during the dry season. The integration of the controlled production of huitlacoche improved productivity and net incomes from the traditional milpa. The traditional milpa system (TMS) had an income of USD $111.00 from maize grains, while the milpa integrating controlled production of huitlacoche galls (TMS + Huitlacoche) had an income of USD $409.00 from galls. This is reflected in the cost/benefit ratio, in which milpa integrating controlled production of huitlacoche galls (TMS + Huitlacoche) was 1.48, while the traditional milpa system (TMS) was not profitable (0.91). Sustainability indicators show that the controlled production of huitlacoche galls contribute to food diversity, productivity, and income in the traditional milpa system, based on the association of maize, beans, squash, and huitlacoche, showing potential for improving food security in rural communities. Full article

Ustilago esculenta is a dimorphic fungus that specifically infects Zizania latifolia, causing stem swelling and the formation of an edible fleshy stem known as jiaobai. The pathogenicity of U. esculenta is closely associated with the development of jiaobai and phenotypic differentiation. Msb2 acts as a key upstream sensor in the MAPK (mitogen-activated protein kinase) signaling pathway, playing critical roles in fungal hyphal growth, osmotic regulation, maintenance of cell wall integrity, temperature adaptation, and pathogenicity. In this study, we cloned the UeMsb2 gene from U. esculenta (GenBank No. MW768949). The open reading frame of UeMsb2 is 3015 bp in length, lacks introns, encodes a 1004-amino-acid protein with a conserved serine-rich domain, and is localized to the vacuole. Expression analysis revealed that UeMsb2 is inducibly expressed during both hyphal growth and infection processes. Deletion of UeMsb2 did not affect haploid morphology or growth rate in vitro but significantly impaired the strain’s mating ability, suppressed filamentous growth, slowed host infection progression, and downregulated the expression of b signaling pathway genes associated with pathogenicity. Notably, the deletion of UeMsb2 did not influence the in vitro growth of U. esculenta under hyperosmotic, thermal, or oxidative stress conditions. These findings underscore the critical role of UeMsb2 in regulating the pathogenicity of U. esculenta. This study provides insights into the interaction between U. esculenta and Z. latifolia, particularly the mechanisms that drive host stem swelling. 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