Search Results (171)

Aspergillus flavus is a globally distributed filamentous fungus of major agricultural and medical importance, capable of producing carcinogenic aflatoxins and forming two specialized developmental structures, conidia and sclerotia. While the molecular framework governing conidiation has been well characterized in Aspergillus nidulans, the corresponding mechanisms in A. flavus remain somewhat unelucidated. In this study, we identified and functionally characterized AfldrnA, a gene encoding a basic helix–loop–helix (bHLH) transcription factor. Targeted deletion of AfldrnA resulted in an aconidial phenotype accompanied by a significant increase in sclerotia formation, whereas complementation with the intact AfldrnA gene restored conidiation and reduced sclerotia development. Phenotypic assays revealed that the ΔAfldrnA mutant exhibited normal vegetative growth, unchanged antifungal susceptibility, and unaffected aflatoxin B₁ production, indicating that AfldrnA primarily regulates developmental rather than metabolic differentiation. Additionally, observed differences between standard and dark incubation conditions suggest that AfldrnA may be involved in environmentally responsive regulation of fungal development. Overall, this study identifies AfldrnA as a pivotal transcriptional regulator essential for coordinating conidiation and sclerotia formation in A. flavus, providing new insights into the genetic and environmental regulation of fungal developmental programs. Full article

White mold caused by Sclerotinia sclerotiorum (Lib.) de Bary continues to threaten yield and quality and remains a stubborn, sometimes unpredictable constraint in many cropping systems. The pathogen’s broad host range and its capacity to persist for years as sclerotia mean that fields can carry risk long after visible symptoms fade. Disease development is often driven by short windows of favorable temperature and moisture that promote germination and ascospore release and dispersal, while myceliogenic infection from soil-borne sclerotia can also initiate disease directly. Yet dependable control is still undermined by durable inoculum, limited stable host resistance, variable biocontrol performance, and shrinking chemical options together with fungicide resistance risk. Here we consolidate current understanding and ongoing uncertainties around sclerotial formation and germination cues, the environmental drivers that shape epidemic onset, and the processes governing host colonization, including the roles of cell wall-degrading enzymes, oxalic acid, and redox regulation, as well as the continuing debate over necrotrophic versus hemibiotrophic phases. Management is considered from a practical perspective, covering cultural risk reduction, forecasting-guided fungicide programmes supported by resistance-management principles, and biological control strategies targeting sclerotia. Across systems, the evidence points to the same lesson: single tactics rarely remain reliable under field variability, whereas integrated packages that reduce soil inoculum and align interventions with risk are more durable. Future priorities include resolving early infection events, improving prediction of carpogenic germination under changing climates, increasing the consistency of biocontrol, and accelerating resistance breeding supported by genomic resources. Full article

Aspergillus flavus (A. flavus) is a common contaminant of food and feed due to the production of aflatoxin B₁, which is susceptible to environmental signals. Nevertheless, how red light plays a role in A. flavus remains unclear. Here, we identified the uncharacterized hypothetical protein G4B84_010091 as a red-light sensor, defined as fungal phytochrome A (FphA), in A. flavus. The fphA knockout strain (ΔfphA) and complementary strain (fphA-com) were successfully constructed to characterize the function of FphA. Our results indicated that aflatoxin B₁ biosynthesis was promoted, while the development of conidia and sclerotia as well as the infection of peanuts were impaired in ΔfphA when compared with WT or fphA-com. The FphA^ΔRR domain deletion mutant exhibited all the phenotypes observed in the ΔfphA strain, indicating that the RR domain is indispensable for the function of FphA. In summary, FphA is involved not only in the formation of spores and sclerotia, but also in aflatoxin B₁ biosynthesis and the pathogenicity of A. flavus, which offers a potential target for novel approaches to controlling the dispersal and toxin production of this fungus. Full article

Aspergillus flavus Link, 1809 is a pathogenic fungus widely present in the environment. It can infect plants and also acts as an opportunistic pathogen affecting humans and other animals. The aflatoxins (AFs), it produces, can cause cancers such as liver cancer. Therefore, in-depth research into the pathogenic mechanisms of A. flavus is crucial. Arp8 (Actin-like protein Arp8) is a unique subunit within the chromatin remodeling complex INO80, regulating processes including chromatin remodeling. However, the biological function of Arp8 in A. flavus remains unclear. This study constructed A. flavus arp8 knockout (Δarp8) and complementation (Com-arp8) strains via homologous recombination. Subsequent research revealed that following the deletion of arp8, A. flavus exhibits a reduction of approximately 51% in conidia production, complete abrogation of sclerotia formation, and significantly impairment of aflatoxin B1 (AFB1) biosynthesis. Crop grain colonization and Bombyx mori Linnaeus, 1758 infection models demonstrated that Arp8 plays a crucial role in A. flavus ability to infect hosts. Environmental stress experiments identified Arp8 as a vital factor for A. flavus in response to various environmental stresses. Quantitative RT-PCR (qRT-PCR) analysis indicated Arp8 achieves its biological functions through corresponding regulatory factors. This study elucidates the biological functions of Arp8 in A. flavus growth and development, pathogenicity, and aflatoxin synthesis, laying a foundation to illuminate the mechanisms of A. flavus pathogenicity and AFs production. Full article

Sclerotium formation represents a critical transition phase in the life cycle of morel, shifting from vegetative growth to dormant structures. The capacity for sclerotium formation directly influences the yield and stability of artificial cultivation. To elucidate the molecular regulatory mechanisms underlying this process, a combined transcriptomics and metabolomics approach was employed to analyze gene expression and metabolite dynamics during sclerotium development of Morchella eximia. A total of 2567 differentially expressed metabolites (DEMs) and 2314 differentially expressed genes (DEGs) were detected, primarily enriched in amino acid metabolism, lipid synthesis, and energy metabolism pathways. Amino acid metabolism facilitates protein synthesis and supplies carbon skeletons, while lipid metabolic networks, particularly de novo fatty acid synthesis from acetyl-CoA precursors, glycerophospholipid metabolism, sphingolipid metabolism, and unsaturated fatty acid biosynthesis, play a central role in sclerotium formation. A regulatory model was constructed, focusing on signal response, transcriptional regulation, nutrient transport and metabolism, morphology transition, lipid accumulation, and membrane system remodeling, demonstrating that lipids not only provide energy storage and membrane structural components for sclerotia but also mediate developmental transitions and environmental adaptation through signaling molecules and regulation of membrane properties. These findings systematically reveal the regulatory network governing morel sclerotium formation at the multi-omics level, with particular emphasis on the central role of lipid metabolism and membrane remodeling. The results offer a theoretical foundation for improving morel cultivation yield and stability through targeted metabolic regulation strategies. Full article

Azole selenoureas exhibit diverse biological functions. However, the synthesis and biological activity of benzothiazole and benzoxazole selenones remained unexplored. Herein, we report the base-catalyzed synthesis of N-difluoromethyl benzothiazole (or benzoxazole) selenone derivatives, which demonstrated significant antifungal efficacy against Rhizoctonia solani, Phytophthora infestans, Botrytis cinerea, and Fusarium oxysporum. Compound 3b exhibited exceptional antifungal activity against R. solani, with an EC₅₀ of 2.10 mg/L. Moreover, it substantially inhibited sclerotia germination (81.5% at 9 mg/L) and formation (79.3% at 9 mg/L), surpassing octhilinone. The protective effect on detached rice leaves and rice seedlings was found to be 43.4% and 85.2% at 100 mg/L, respectively, and 64.4% and 89.4% at 200 mg/L. These findings suggest that benzothiazole and benzoxazole selenones represent promising lead compounds for sustainable plant disease management. Full article

Ergot alkaloids derived from lysergic acid have impacted humankind significantly as toxins in agriculture and as the foundations of several pharmaceuticals. Few fungi capable of producing lysergic acid derivatives have been found outside the family Clavicipitaceae. Based on its phylogenetic placement, we hypothesized the recently described fungus Aspergillus aspearensis (Aspergillaceae) would synthesize lysergic acid amides. Cultures of A. aspearensis produced abundant lysergic acid α-hydroxyethylamide (LAH) and lesser amounts of other lysergic acid derivatives. Conidia contained high concentrations of ergot alkaloids, whereas sclerotia contained significantly less. Approximately half of the ergot alkaloids produced were secreted into the culture medium. When spores of A. aspearensis were injected into larvae of the model insect Galleria mellonella, larvae died at a significantly faster rate than control larvae. The fungus produced ergot alkaloids during insect pathogenesis and later produced conidia and sclerotia on cadavers, indicating it can complete its life cycle in an insect. The genome of A. aspearensis contained two complete ergot alkaloid synthesis gene clusters, similar to those of A. leporis; however, unlike its sister species, none of the ergot cluster genes were pseudogenized. Aspergillus aspearensis is a newly discovered source of ergot alkaloids and may be useful for studying and producing these important chemicals. Full article

Sclerotinia spp. are globally distributed, devastating plant pathogens with a broad host range, including lettuce, on which they cause lettuce drop disease. To investigate the geographical distribution of lettuce drop incidence and the population structure of Sclerotinia sclerotiorum and S. minor in Serbia, 27 commercial lettuce fields across 12 administrative districts were surveyed. Sclerotinia spp. were confirmed at 10 localities, with S. sclerotiorum occurring more frequently. Co-occurrence of both species within the same field was recorded at only one location. Clear phenotypic and physiological differences were found between Sclerotinia species, as well as among isolates within each species. The two species differed in colony appearance, sclerotia production, virulence, growth rate, oxalic acid production, and tolerance to elevated osmotic pressure. Haplotype analysis of S. minor revealed the existence of 9 haplotypes arranged in a star-shaped network. These findings highlight the importance of considering both inter- and intraspecific variability of Sclerotinia species when evaluating their impact on crops, improving our understanding of Sclerotinia populations in lettuce, and supporting the development of effective management strategies. Full article

White mold (Sclerotinia sclerotiorum) reduces potato yield and quality in Sinaloa, Mexico. This study first evaluated the in vitro efficacy of Trichoderma azevedoi, T. afroharzianum, T. asperellum and T. asperelloides in inhibiting S. sclerotiorum mycelial growth and sclerotia production. Field experiments then assessed a combination of these antagonists, their alternating application with synthetic fungicides, and a fungicide-alone treatment for disease control, sclerotia reduction and yield increase. In vitro, all four Trichoderma species significantly inhibited the pathogen, achieving 60.1–63.1% mycelial suppression in dual culture and 90.3–94.1% via volatile metabolites, with the latter also completely suppressing sclerotia formation. In the field, the Trichoderma combination significantly controlled white mold, reducing plant incidence and severity to 66.0 and 27.1% in 2021 and 55.6 and 18.8% in 2022, while lowering sclerotia production to 32.7 and 14.6 on ten plants, respectively. This control extended to tubers, where incidence and severity were reduced to 1.6% and 0.4% in 2021, and 1.3% and 0.3% in 2022. The alternating application of Trichoderma with synthetic fungicides proved statistically equivalent to the Trichoderma-alone treatment in disease control, while the fungicides-alone treatment was significantly less effective. Potato yield was highest in plots treated with the Trichoderma combination (46.0 and 52.9 t ha⁻¹ in 2021 and 2022, respectively). These results highlight the potential of using a mixture of these four Trichoderma species as a cornerstone of sustainable disease management in Sinaloa, offering effective control of potato white mold while significantly reducing dependence on synthetic fungicides. Full article

Colombia is the Latin American country with the second-largest area planted with OxG hybrid cultivars, covering more than 120,000 hectares Various health problems can affect yield, especially those affecting fruit. Since 2021, white fruit rot has been reported in the northern, central, and southwestern palm-growing areas. Therefore, the objective of this study is to identify associated symptoms and their causal agent. To this end, a total of six locations in the three palm-growing regions were visited, and 36 samples of affected fruits were collected to obtain microorganisms. These microorganisms were inoculated into detached fruits under in vitro conditions, and seven isolates were inoculated into bunches in the field. They were morphologically and molecularly characterized by partial sequencing of the ITS and TEF1 regions. Symptoms of white rot were observed, starting from the base of the fruit to the apex, with the development of a cottony mycelial mass, followed by the formation of sclerotia. A total of 33 organisms were obtained, 30 isolates identified as Agroathelia rolfsii, one Fusarium sp., one Rhizoctonia sp., and one Pestalotiopsis sp. isolate. The Agroathelia isolates exhibited white, cottony growth adhering to the surface of the PDA culture medium. After four days of growth, they developed globose to ellipsoid sclerotia (average 1.00 ± 0.26 (0.46–2.20 mm)). These were initially white and turned brown as they developed, with the average number of sclerotia per plate ranging from 4 to 449 (n = 6). In the in vitro pathogenicity test, only A. rolfsii isolates were pathogenic, with a 100% incidence, an average severity ranging from 10 to 40% infection, and a range of 10 to 100%. In field inoculations, 100% of the inoculated bunches exhibited symptoms similar to those observed under natural field conditions. In all cases, the pathogen was recovered, fulfilling Koch’s postulates and confirming that A. rolfsii is the causal agent of white fruit rot. This constitutes the first record of Agroathelia rolfsii in oil palm in Colombia. Full article

Aspergillus flavus colonizes oil-seed crops, contaminating them with aflatoxins; highly carcinogenic mycotoxins that cause severe health and economic losses. Genetic studies may reveal new targets for effective control strategies. Here, we characterized a putative WOPR transcription factor gene, osaA, in A. flavus. Our results revealed that osaA regulates conidiation and sclerotial formation. Importantly, deletion of osaA reduces aflatoxin B₁ production, while, unexpectedly, transcriptome analysis indicated upregulation of aflatoxin biosynthetic genes, suggesting post-transcriptional or cofactor-mediated regulation. Cyclopiazonic acid production also decreased in the absence of osaA. In addition, the osaA mutant exhibited upregulation of genes in the imizoquin and aspirochlorine clusters. Moreover, osaA is indispensable for normal seed colonization; deletion of osaA significantly reduced fungal burden in corn kernels. Aflatoxin content in seeds also decreased in the absence of osaA. Furthermore, deletion of osaA caused a reduction in cell-wall chitin content, as well as alterations in oxidative stress sensitivity, which could in part contribute to the observed reduction in pathogenicity. Additionally, promoter analysis of osaA-dependent genes indicated potential interactions with stress-responsive regulators, indicated by an enrichment in Sko1 and Cst6 binding motifs. Understanding the osaA regulatory scope provides insight into fungal biology and identifies potential targets for controlling aflatoxin contamination and pathogenicity. Full article

Sclerotium rolfsii Sacc. is a soil-borne fungus that causes southern blight on many crops in the tropical and subtropical regions. In 2018, southern blight was reported as the most prevalent bean root rot in Uganda. Earlier studies ascertained the morphological and pathogenic diversity of S. rolfsii, but a limited understanding of its genetic diversity exists. Knowledge of S. rolfsii genetic diversity is a critical resource for pathogen surveillance and developing common bean varieties with durable resistance. A total of 188 S. rolfsii strains from infected common bean plants were collected from seven agro-ecological zones of Uganda in 2013, 2020 and 2021, and characterized morphologically and pathogenically. The genetic diversity of the strains was assessed using single-nucleotide polymorphisms (SNPs) obtained from whole-genome sequencing. The growth rate of the strains ranged between 1.1 and 3.6 cm per day, while the number of sclerotia produced ranged from 0 to 543 per strain. The strains had fluffy, fibrous, and compact colony texture. The strains were pathogenic on common bean and caused disease severity indices ranging from 10.1% to 93.3%. Average polymorphic information content across all chromosomes was 0.27. Population structure analysis identified five genetically distinct clusters. The results of analysis of molecular variance revealed that 54% of the variation was between clusters while 46% of variation was within clusters. Pairwise comparison of Wright’s fixation indices between genetic clusters ranged from 0.31 to 0.78. The findings of this study revealed moderate genetic diversity among S. rolfsii strains, which should be taken into consideration when selecting strains for germplasm screening. Full article

Rice production experiences significant losses due to fungal diseases, particularly rice sheath blight caused by Rhizoctonia solani. Despite the intensive and continuous use of synthetic fungicides, diseases severity has not reduced and control has become increasingly challenging; therefore, the search for environmentally friendly and sustainable products has intensified. Here, we conducted a chemical characterization of Xylopia frutescens and using in silico analysis evaluated the interaction of their two major compounds with lectin protein site of R. solani. In vitro tests using increasing concentrations of essential oil against R. solani were performed. Subsequently, in four varieties of rice, five concentrations of X. frutescens essential oils were applied and evaluated the phytotoxicity effect as well the potential of Xylopia frutescens essential oil for controlling, both preventively and curatively, rice sheath blight. We further investigate the selectivity of this essential oil towards the non-target organism, Trichoderma asperellum. Our analysis revealed that trans-pinocarveol and myrtenal are the main compounds of X. frutescens essential oil and interact with the lectin of R. solani, supporting the antifungal properties of X. frutescens essential oil. In in vitro conditions, the highest tested concentrations of X. frutescens essential oil inhibited the pathogen’s sclerotia and mycelial growth. Under greenhouse conditions, the treatments caused low phytotoxicity and effectively reduced disease severity when applied, both preventively and curatively. Furthermore, the biocontrol agent T. asperellum exhibited tolerance to X. frutescens essential oil. Collectively, our findings demonstrate the potential of X. frutescens essential oil for the development of botanical fungicides capable of controlling R. solani without harming beneficial non-target organisms such as T. asperellum. Full article

Background/Objectives: Ergot alkaloids are mycotoxins produced mainly by fungi of the genus Claviceps, infecting a wide variety of plants, especially cereals. These toxins usually manifest as black, hardened sclerotia (ergots), though they may also be invisible when dispersed in grain. They pose a significant risk to animals and humans when present in contaminated cereals. They can cause ergotism, with vasoconstriction, ischemia, hallucinations, and in severe cases gangrene. This study was carried out in response to the European legislative actions which determine the permissible levels of ergot alkaloids in cereals. Historically, consumers manually removed visible sclerotia from grain, and farmers applied fertilizers or timed harvests to specific periods to mitigate contamination. However, these traditional methods have proven insufficient. We therefore explored advanced techniques for detecting and quantifying ergot-contaminated cereals, as well as methods for reducing ergot alkaloid concentrations. Methods: Searches were conducted in scientific databases including Google Scholar, PubMed, and Scopus to identify research articles, reviews, and experimental studies published mainly between 2012 and August 2025, including accepted or in-press manuscripts, with special attention to works from 2021 onward to capture the most recent advancements. Results/Conclusions: Ultra-high-performance liquid chromatography–tandem mass spectrometry (UHPLC-MS/MS) is the reference method for confirmatory, epimer-aware quantification of ergot alkaloids, and is already standardized. Recent QuEChERS-UHPLC-MS/MS workflows in cereal matrices, including oat-based products, routinely achieve limits of quantification of about 0.5–1.0 µg/kg with single-run analysis times of about 5–15 min. Rapid screening options complement, rather than replace, confirmatory mass spectrometry: magnetic bead-based immunoassays that use magnetic separation and a smartphone-linked potentiostat provide sub-hour turnaround and field portability for trained quality-assurance staff, although external validation and calibration traceable to LC-MS/MS remain prerequisites for routine use. In practice, operators are adopting tiered, orthogonal workflows (e.g., immunoassay or electronic-nose triage at intake followed by DNA-based checks on grain washings and LC–MS/MS confirmation, or hydrazinolysis “sum parameter” screening followed by targeted MS speciation). Such combinations reduce turnaround time while preserving analytical rigor. Biotechnology also offers potential solutions for reducing ergot alkaloid concentrations at the source. Finally, to enhance consumer safety, artificial intelligence and blockchain-based food traceability appear highly effective. These systems can connect all stakeholders from producers to consumers, allowing for real-time updates on food safety and rapid responses to contamination issues. This review primarily synthesizes advances in analytical detection of ergot alkaloids, while mitigation strategies and supply chain traceability are covered concisely as supporting context for decision making. Full article

Sclerotinia sclerotiorum (Lib.) de Bary, the causal agent of Sclerotinia stem rot (SSR) or white mold, is a soil-borne hemibiotrophic fungus that causes substantial soybean yield losses worldwide. This pathogen infects over 400 plant species and persists in soil for extended periods through melanized sclerotia, which can survive under extreme environmental conditions. The wide host range, environmental adaptability, and longevity of sclerotia make SSR a persistent challenge in soybean production. No single management tactic provides reliable control, which underscores the importance of integrated pest management (IPM). Cultural practices such as crop rotation with non-hosts, optimized row spacing, adjusted seeding rates, and targeted irrigation are fundamental to reducing inoculum and modifying canopy microclimates to slow infection. Although genetic resistance remains partial, the deployment of cultivars with stable performance across environments contributes to disease suppression, particularly when combined with fungicide applications. However, fungicide efficacy is inconsistent and limited due to environmental concerns and potential resistance. Advances in disease modeling have improved the timing and precision of chemical control, while biological control agents and RNA interference approaches offer promising future options. This review synthesizes current IPM strategies for SSR and explores emerging alternatives to support sustainable soybean production. Full article