Fungal Pathogens Research Articles

Strain variation in the Candida albicans iron limitation response.

Iron acquisition is critical for pathogens to proliferate during invasive infection, and the human fungal pathogen Candida albicans is no exception. The iron regulatory network, established in reference strain SC5314 and derivatives, includes the central player Sef1, a transcription factor that activates iron acquisition genes in response to iron limitation. Here, we explored potential variation in this network among five diverse C. albicans strains through mutant analysis, Nanostring gene expression profiling, and, for two strains, RNA-Seq. Our findings highlight four features that may inform future studies of natural variation and iron acquisition in this species. (i) Conformity: In all strains, major iron acquisition genes are upregulated during iron limitation, and a sef1Δ/Δ mutation impairs that response and growth during iron limitation. (ii) Response variation: Some aspects of the iron limitation response vary among strains, notably the activation of hypha-associated genes. As this gene set is tied to tissue damage and virulence, variation may impact the progression of infection. (iii) Genotype-phenotype variation: The impact of a sef1Δ/Δ mutation on cell wall integrity varies, and for the two strains examined the phenotype correlated with sef1Δ/Δ impact on several cell wall integrity genes. (iv) Phenotype discovery: DNA repair genes were induced modestly by iron limitation in sef1Δ/Δ mutants, with fold changes we would usually ignore. However, the response occurred in both strains tested and was reminiscent of a much stronger response described in Cryptococcus neoformans, a suggestion that it may have biological meaning. In fact, we observed that the iron limitation of a sef1Δ/Δ mutant caused recessive phenotypes to emerge at two heterozygous loci. Overall, our results show that a network that is critical for pathogen proliferation presents variation outside of its core functions.IMPORTANCEA key virulence factor of Candida albicans is the ability to maintain iron homeostasis in the host where iron is scarce. We focused on a central iron regulator, SEF1. We found that iron regulator Sef1 is required for growth, cell wall integrity, and genome integrity during iron limitation. The novel aspect of this work is the characterization of strain variation in a circuit that is required for survival in the host and the connection of iron acquisition to genome integrity in C. albicans.

A high-quality genome assembly and annotation of Thielaviopsis punctulata DSM102798

Black scorch disease (BSD), caused by the fungal pathogen Thielaviopsis punctulata (Tp) DSM102798, poses a significant threat to date palm cultivation in the United Arab Emirates (UAE). In this study, Chicago and Hi-C libraries were prepared as input for the Dovetail HiRise pipeline to scaffold the genome of Tp DSM102798. We generated an assembly with a total length of 28.23 Mb comprising 1,256 scaffolds, and the assembly had a contig N50 of 18.56 kb, L50 of three, and a BUSCO completeness score of 98.6% for 758 orthologous genes. Annotation of this assembly produced 7,169 genes and 3,501 Gene Ontology (GO) terms. Compared to five other Thielaviopsis genomes, Tp DSM102798 exhibited the highest continuity with a cumulative size of 27.598 Mb for the first seven scaffolds, surpassing the assemblies of all examined strains. These findings offer a foundation for targeted strategies that enhance date palm resistance against BSD, and foster more sustainable and resilient agricultural systems.

The spliceosome impacts morphogenesis in the human fungal pathogen Candida albicans.

At human body temperature, the fungal pathogen Candida albicans can transition from yeast to filamentous morphologies in response to host-relevant cues. Additionally, elevated temperatures encountered during febrile episodes can independently induce C. albicans filamentation. However, the underlying genetic pathways governing this developmental transition in response to elevated temperatures remain largely unexplored. Here, we conducted a functional genomic screen to unravel the genetic mechanisms orchestrating C. albicans filamentation specifically in response to elevated temperature, implicating 45% of genes associated with the spliceosome or pre-mRNA splicing in this process. Employing RNA-Seq to elucidate the relationship between mRNA splicing and filamentation, we identified greater levels of intron retention in filaments compared to yeast, which correlated with reduced expression of the affected genes. Intriguingly, homozygous deletion of a gene encoding a spliceosome component important for filamentation (PRP19) caused even greater levels of intron retention compared with wild type and displayed globally dysregulated gene expression. This suggests that intron retention is a mechanism for fine-tuning gene expression during filamentation, with perturbations of the spliceosome exacerbating this process and blocking filamentation. Overall, this study unveils a novel biological process governing C. albicans filamentation, providing new insights into the complex regulation of this key virulence trait.IMPORTANCEFungal pathogens such as Candida albicans can cause serious infections with high mortality rates in immunocompromised individuals. When C. albicans is grown at temperatures encountered during human febrile episodes, yeast cells undergo a transition to filamentous cells, and this process is key to its virulence. Here, we expanded our understanding of how C. albicans undergoes filamentation in response to elevated temperature and identified many genes involved in mRNA splicing that positively regulate filamentation. Through transcriptome analyses, we found that intron retention is a mechanism for fine-tuning gene expression in filaments, and perturbation of the spliceosome exacerbates intron retention and alters gene expression substantially, causing a block in filamentation. This work adds to the growing body of knowledge on the role of introns in fungi and provides new insights into the cellular processes that regulate a key virulence trait in C. albicans.

Screening the Potential f Fungal Derived Bioherbicide in Weed Management

Synthetic herbicides have long been a cornerstone of modern agriculture, providing effective weed control but often at significant environmental and health costs. These chemicals can persist in the environment, leach into groundwater, and harm non-target organisms, including humans. Additionally, the overuse of synthetic herbicides has led to the development of herbicide-resistant weeds, further complicating weed management strategies. In response to these challenges, researchers and farmers alike are increasingly turning to bioherbicides derived from fungi as a sustainable alternative. Fungal bioherbicides harness the natural antagonistic properties of fungi to target weeds. Unlike synthetic herbicides, which are chemically synthesized and often broad-spectrum in action, fungal bioherbicides utilize either the fungi themselves as pathogens or their metabolites to disrupt weed growth. This approach offers several distinct advantages:Target Specificity: Fungal bioherbicides can be highly specific to certain weed species or even to specific stages of weed growth. This specificity reduces collateral damage to non-target plants and organisms, making them particularly suitable for environmentally sensitive areas such as organic farms, riparian zones, and protected ecosystems. Environmental Friendliness: Unlike synthetic herbicides that can persist in the environment and accumulate in soil and water bodies, fungal bioherbicides generally have lower persistence. They degrade more rapidly and often have minimal impact on non-target organisms, thereby preserving biodiversity and ecosystem health. Reduced Risk of Resistance: Synthetic herbicides often face the challenge of herbicide-resistant weeds, which evolve due to continuous and widespread use. Fungal bioherbicides, by contrast, pose a lower risk of resistance development. This is because they typically act through multiple modes of action or biochemical pathways within the weed, making it harder for weeds to develop resistance mechanisms. Research into fungal-derived bioherbicides is actively exploring and harnessing these advantages. Scientists are screening diverse fungal species to identify potent pathogens or metabolites that effectively inhibit weed growth. Moreover, advances in biotechnology and genetic engineering allow for the enhancement of fungal strains to optimize their bioherbicidal properties while ensuring safety and efficacy. One promising example is the use of fungal pathogens like Phomamacrostoma and Colletotrichum truncatum, which have demonstrated efficacy against various weed species including common agricultural weeds like velvetleaf and pigweed. These fungi infect weeds through mechanisms such as spore attachment, penetration of plant tissues, and secretion of phytotoxic metabolites that inhibit weed growth. In addition to their direct impact on weed management, fungal bioherbicides contribute to sustainable agricultural practices by reducing reliance on synthetic chemicals. They align with principles of integrated pest management (IPM) by offering a biological control method that complements cultural and mechanical weed control strategies. Moving forward, continued research and development efforts are essential to refine fungal bioherbicides, optimize application techniques, and expand their practical use in diverse agricultural settings. Challenges such as formulation stability, cost-effectiveness, and regulatory approvals also need to be addressed to facilitate widespread adoption by farmers.

Screening the Potential f Fungal Derived Bioherbicide in Weed Management

Synthetic herbicides have long been a cornerstone of modern agriculture, providing effective weed control but often at significant environmental and health costs. These chemicals can persist in the environment, leach into groundwater, and harm non-target organisms, including humans. Additionally, the overuse of synthetic herbicides has led to the development of herbicide-resistant weeds, further complicating weed management strategies. In response to these challenges, researchers and farmers alike are increasingly turning to bioherbicides derived from fungi as a sustainable alternative. Fungal bioherbicides harness the natural antagonistic properties of fungi to target weeds. Unlike synthetic herbicides, which are chemically synthesized and often broad-spectrum in action, fungal bioherbicides utilize either the fungi themselves as pathogens or their metabolites to disrupt weed growth. This approach offers several distinct advantages:Target Specificity: Fungal bioherbicides can be highly specific to certain weed species or even to specific stages of weed growth. This specificity reduces collateral damage to non-target plants and organisms, making them particularly suitable for environmentally sensitive areas such as organic farms, riparian zones, and protected ecosystems. Environmental Friendliness: Unlike synthetic herbicides that can persist in the environment and accumulate in soil and water bodies, fungal bioherbicides generally have lower persistence. They degrade more rapidly and often have minimal impact on non-target organisms, thereby preserving biodiversity and ecosystem health. Reduced Risk of Resistance: Synthetic herbicides often face the challenge of herbicide-resistant weeds, which evolve due to continuous and widespread use. Fungal bioherbicides, by contrast, pose a lower risk of resistance development. This is because they typically act through multiple modes of action or biochemical pathways within the weed, making it harder for weeds to develop resistance mechanisms. Research into fungal-derived bioherbicides is actively exploring and harnessing these advantages. Scientists are screening diverse fungal species to identify potent pathogens or metabolites that effectively inhibit weed growth. Moreover, advances in biotechnology and genetic engineering allow for the enhancement of fungal strains to optimize their bioherbicidal properties while ensuring safety and efficacy. One promising example is the use of fungal pathogens like Phomamacrostoma and Colletotrichum truncatum, which have demonstrated efficacy against various weed species including common agricultural weeds like velvetleaf and pigweed. These fungi infect weeds through mechanisms such as spore attachment, penetration of plant tissues, and secretion of phytotoxic metabolites that inhibit weed growth. In addition to their direct impact on weed management, fungal bioherbicides contribute to sustainable agricultural practices by reducing reliance on synthetic chemicals. They align with principles of integrated pest management (IPM) by offering a biological control method that complements cultural and mechanical weed control strategies. Moving forward, continued research and development efforts are essential to refine fungal bioherbicides, optimize application techniques, and expand their practical use in diverse agricultural settings. Challenges such as formulation stability, cost-effectiveness, and regulatory approvals also need to be addressed to facilitate widespread adoption by farmers.

Research Progress on Diseases Caused by the Soil-Borne Fungal Pathogen Rhizoctonia solani in Alfalfa

Rhizoctonia solani is a soil-borne fungal species with worldwide distribution and poses serious threats to a wide range of economically important crops such as grain and forage crops. This pathogen has survival capabilities within plants and soil, giving rise to sclerotia and persisting for several months or years. Alfalfa (Medicago sativa) is the most widely grown and important forage crop in China and worldwide. The unique characteristics of alfalfa, such as excellent forage quality, ruminant desirability, and substantial biomass output, distinguish it from other fodder crops, and it is also known as the “Queen of Forages”. However, the production of alfalfa is seriously affected by R. solani, with yield losses of 20% to 60% globally. This review firstly summarizes diseases such as seedling damping-off, root rot, crown rot, root cankers, stem cankers, blight, and stem rot caused by R. solani in alfalfa and the survival mechanism of this pathogen. The techniques for R. solani detection and quantification from plants and soils, as well as management through host resistance, cultural practices, fungicides, and biological control, were then overviewed. This review provides scientific knowledge to enable researchers to efficiently manage R. solani in alfalfa production.

A high-quality genome assembly and annotation of Thielaviopsis punctulata DSM102798

Black scorch disease (BSD), caused by the fungal pathogen Thielaviopsis punctulata (Tp) DSM102798, poses a significant threat to date palm cultivation in the United Arab Emirates (UAE). In this study, Chicago and Hi-C libraries were prepared as input for the Dovetail HiRise pipeline to scaffold the genome of Tp DSM102798. We generated an assembly with a total length of 28.23 Mb comprising 1,256 scaffolds, and the assembly had a contig N50 of 18.56 kb, L50 of three, and a BUSCO completeness score of 98.6% for 758 orthologous genes. Annotation of this assembly produced 7,169 genes and 3,501 Gene Ontology (GO) terms. Compared to five other Thielaviopsis genomes, Tp DSM102798 exhibited the highest continuity with a cumulative size of 27.598 Mb for the first seven scaffolds, surpassing the assemblies of all examined strains. These findings offer a foundation for targeted strategies that enhance date palm resistance against BSD, and foster more sustainable and resilient agricultural systems.

Brilacidin, a host defense peptide mimetic, potentiates ibrexafungerp antifungal activity against the human pathogenic fungus Aspergillus fumigatus.

Invasive fungal infections have a high mortality rate causing more deaths annually than tuberculosis or malaria. Aspergillus fumigatus causes a series of distinct invasive fungal infections have a high mortality rate causing more deaths annually than tuberculosis or malaria. A. fumigatus causes a spectrum of distinct clinical entities named aspergillosis, which the most severe form is the invasive pulmonary aspergillosis. There are few therapeutic options for treating aspergillosis and searching for new antifungal agents against this disease is very important. Here, we present brilacidin (BRI) as a synergizer o fibrexafungerp (IBX) against A. fumigatus. BRI is a small molecule host defense peptide mimetic that has previously exhibited broad-spectrum immunomodulatory/anti-inflammatory activity against bacteria and viruses. We propose the combination of BRI and IBX as a new antifungal combinatorial treatment against aspergillosis.

First report of Fusarium humuli causing stem spots in Nicotiana tabacum L in China.

Tobacco is one of the most important economic crops in China. Disease is one of the main factors affecting the quality of tobacco production (Cai et al. 2022). Stem spot disease of tobacco was observed in the Planting Demonstration Garden in Chang Ning (26°37N; 112° 31E), Hunan Province of China, from May to June 2023. The disease seriously retarded tobacco growth and the incidence rate was about 30-50% of the plants(Yun Yan 87). Most of infected tobacco had black spots on the stems, and the spots expanded and joined together quickly, while many stems turned black and withered. For pathogen isolation, symptomatic stem samples were collected and disinfected with 75% ethanol for 30 s and 2% sodium hypochlorite for 1 minute, followed by rinsing with sterile distilled water three times. Subsequently, small pieces (5 × 5 mm) of diseased tissues were placed on potato dextrose agar (PDA) and incubated in the dark at 25 °C for 24 h to 36 h. The emerging fungal hyphal tips were transferred to PDA and purified by the single-spore method(Yu et al. 2022). In total, 16 cultures with the same appearance were isolated from 30 disease spots on the stem. Strain coded as hnxryc2 was randomly selected for identification. After culturing in PDA for 7 days, white and dense colonies wereobserved with a mean radial growth rate of 6.4 mm/day. The strain cultured 10 days on SNA. Morphological observations were made on 10-day-old culture on SNA medium, and macroconidia were sickle-shaped and slightly curved, with 3-5 septa (2.32-7.00 µm × 0.53-1.17 µm, n = 50), neither microconidia nor chlamydospores were observed. These morphological characteristics were consistent with the description of Fusarium humuli (Wang et al. 2019, Li et al. 2023). Furthermore, primers ITS1/ITS4, EF728F/EF986R, RPB1-F5/RPB1-R8 and fRPB2-5F2/fRPB2-7cR(Xie et al. 2023) were used to amplify the ITS region, EF-1α, RPB1, and RPB2 from strain hnxryc2, respectively. The sequence alignment of hnxryc2 with the NCBI database and FUSARIOID-ID shows the following results: The sequence of ITS region(GenBank accession number PP543715) was 100% identical to these of Fusarium sp. (MN428026.1), the sequences of EF-1α, RPB1, and RPB2 of strain hnxryc2(GenBank accession numbersOR257586, OR326856 and OR257587 respectively) were 99% to 100% identical to these of F. humuli (GenBank accession numbers MK289578.1, MZ824672.1 and MZ824673.1, respectively). Then a phylogenetic tree based on ITS region, EF-1α, and RPB2 sequences was constructed (Kroon et al. 2004). The strain hnxryc2 was more closely related to F. humuli (CGMCC3.19374 GenBank accession nos. MK280845.1, MK289570.1 and MK289724.1, respectively), with bootstrap values 88%. Pathogenicity tests were performed on detached stems of tobacco and potted plants. Wounded stems were inoculated with conidial suspensions (100 μL, 1×107 spores/mL), and the controls were inoculated with sterile water (Xu et al. 2023). The inoculated detached stems were kept in humid chambers (Zhong et al., 2019), each treatment was given a 12h/12h light/dark cycle at 25°C. Deep black spots were observed for 3 days after inoculation. After 9 days, typical symptoms similar to the original diseased plants in the field were found on all inoculated stems, while the control stems did not exhibit any symptoms. Pathogenicity assays were repeated thrice. The pathogen F. humuli was successfully reisolated from the stem of inoculated samples showing symptoms. To our knowledge, this is the first report of F. humuli inducing stem spot on tobacco in China. Since F. humuli is a common pathogenic fungus that infects different plant species, more attention should be paid to its prevalence in tobacco, and the potential risk of a disease outbreak in other provinces of China.

Screening of bread wheat genotypes for identification of novel stripe rust resistance genes using molecular markers

Stripe Rust, caused by Puccinia striiformis Westend f. sp. tritici , is an important fungal disease of wheat worldwide. In this study, 41 wheat genotypes from various institutes across India were screened for adult plant resistance (APR) in field trials, and the presence of effective stripe rust resistance genes was evaluated in the laboratory using ten molecular markers.The bread wheat variety Agra local was used as a susceptible control. Molecular characterization studies revealed that the gene Yr 2 was found in 29 entries, Yr5 in 15 entries, Yr9 in 7 entries, Yr10 in 18 entries, Yr15 in 18 entries, Yr17 in 12 entries, Yr18 in 29 entries, Yr36 in 21 entries, Yr40 in 31 entries while Yr65 was absent in all the entries. The genotypes PBW780 and High Rainfall Wheat Screening Nursery (HRWSN) line 2105 had seven Yr genes conferring resistant phenotypes, suggesting that these were excellent sources of effectual stripe rust resistance. The coefficient of infection showed adequate genotypic variations for rust severity, 41 genotypes showed year-specific responses, suggesting strong G × E interactions.

Validating genetic variants in innate immunity linked to infectious events in acute myeloid leukemia post-induction chemotherapy.

Infectious events, such as sepsis and invasive fungal disease (IFD), pose significant risks in patients with acute myeloid leukemia (AML). Previous studies, including our own, have suggested a potential role of single nucleotide polymorphisms (SNPs) within the innate immune system in influencing individual infection susceptibility. However, many of these associations lack validation in independent cohorts. This study sought to validate the impact of 11 candidate SNPs across 6 genes (TLR2, TLR4, Dectin-1, DC-SIGN, PTX3, L-Ficolin) in an independent cohort of patients. Two cohorts with newly diagnosed AML patients receiving intensive induction chemotherapy were analyzed: a stratification cohort comprising 186 patients and a validation cohort consisting of 138 patients. Multiple SNPs in each cohort were found to be associated to infectious complications, notably the DC-SIGN SNP rs4804800 demonstrated a significant association with sepsis in both cohorts. SNPs within the PTX3 and Dectin-1 genes were linked to IFD development in one cohort each. This study represents the first validation study of candidate genes associated with infectious events in AML patients after intensive induction chemotherapy. Identifying genetic predispositions to infections could significantly impact the management of antimicrobial prophylaxis and treatment in AML patients.

Screening of bread wheat genotypes for identification of novel stripe rust resistance genes using molecular markers

Stripe Rust, caused by Puccinia striiformis Westend f. sp. tritici , is an important fungal disease of wheat worldwide. In this study, 41 wheat genotypes from various institutes across India were screened for adult plant resistance (APR) in field trials, and the presence of effective stripe rust resistance genes was evaluated in the laboratory using ten molecular markers.The bread wheat variety Agra local was used as a susceptible control. Molecular characterization studies revealed that the gene Yr 2 was found in 29 entries, Yr5 in 15 entries, Yr9 in 7 entries, Yr10 in 18 entries, Yr15 in 18 entries, Yr17 in 12 entries, Yr18 in 29 entries, Yr36 in 21 entries, Yr40 in 31 entries while Yr65 was absent in all the entries. The genotypes PBW780 and High Rainfall Wheat Screening Nursery (HRWSN) line 2105 had seven Yr genes conferring resistant phenotypes, suggesting that these were excellent sources of effectual stripe rust resistance. The coefficient of infection showed adequate genotypic variations for rust severity, 41 genotypes showed year-specific responses, suggesting strong G × E interactions.

A single gene mutation underpins metabolic adaptation and acquisition of filamentous competence in the emerging fungal pathogen Candida auris.

Filamentous cell growth is a vital property of fungal pathogens. The mechanisms of filamentation in the emerging multidrug-resistant fungal pathogen Candida auris are poorly understood. Here, we show that exposure of C. auris to glycerol triggers a rod-like filamentation-competent (RL-FC) phenotype, which forms elongated filamentous cells after a prolonged culture period. Whole-genome sequencing analysis reveals that all RL-FC isolates harbor a mutation in the C2H2 zinc finger transcription factor-encoding gene GFC1 (Gfc1 variants). Deletion of GFC1 leads to an RL-FC phenotype similar to that observed in Gfc1 variants. We further demonstrate that GFC1 mutation causes enhanced fatty acid β-oxidation metabolism and thereby promotes RL-FC/filamentous growth. This regulation is achieved through a Multiple Carbon source Utilizer (Mcu1)-dependent mechanism. Interestingly, both the evolved RL-FC isolates and the gfc1Δ mutant exhibit an enhanced ability to colonize the skin. Our results reveal that glycerol-mediated GFC1 mutations are beneficial during C. auris skin colonization and infection.

Structure and Function of Fungal Community in Channel Sediments of Different Sections of Jialing River

This study aimed to explore the effects of different disturbances on the fungal communities in the sediments of the Jialing River in order to provide scientific basis for the protection of the river ecosystem. The fungal community in the sediments of the main stream of the Jialing River was taken as the research object, and high-throughput sequencing and bioinformatics techniques were used to analyze the differences in the composition and function of fungal communities in river sediment of different types of disturbance （project disturbance, tributary disturbance, sand mining disturbance, and reclamation disturbance） and non-disturbance sections. The results showed that： ① The reclamation and project disturbances significantly inhibited the diversity and richness of fungal communities （P<0.05）. The tributary disturbance increased the richness of fungal communities, whereas the impact of sand mining disturbance on sediment fungal communities was not significant. ② The diversity and composition of fungal communities tended to be similar at the different sampling sites in the section with low input of exogenous substances （non-disturbance and sand mining disturbance）, whereas there were obvious differences in the diversity of fungal communities at the different sampling sites of high input of external substances （tributary disturbance, project disturbance, and reclamation disturbance） sections. ③ Ascomycota, Rozellomycota, and Basidiomycota were the main dominant fungal phyla in the sediments of the Jialing River. The relative abundance of Rozellomycota was the highest in the sand mining interference section, and the relative abundance of Basidiomycota was the highest in the tributary interference section. Project disturbance significantly increased the relative abundance of saprotrophs, animal pathogens, plant pathogens, and dung saprotrophs, whereas other disturbances inhibited the relative abundance of fungal parasitic fungi, plant pathogens, and plant saprophytes. In conclusion, human disturbance has caused changes in fungal diversity, community structure, and function in the sediment of the Jialing River, and xenobiotic input was a key factor contributing to this phenomenon. The results can provide a reference for predicting and evaluating the ecological quality of river sediments.

Gene-specific transcriptional activation by the Aspergillus fumigatus AtrR factor requires a conserved C-terminal domain.

Aspergillus fumigatus is the primary human filamentous fungal pathogen. The principal chemotherapeutic drug used to control infections associated with A. fumigatus is the azole compound. These drugs are well-tolerated and effective, but resistance is emerging at an alarming rate. Most resistance is associated with mutations that lead to overexpression of the azole target enzyme, lanosterol α-14 demethylase, encoded by the cyp51A gene. A key regulator of cyp51A gene expression is the transcription factor AtrR. Very little is known of the molecular mechanisms underlying the effect of AtrR on gene expression. Here, we use deletion and clustered amino acid substitution mutagenesis to map a region of AtrR that confers gene-specific activation on target genes of this transcription factor. This region is highly conserved across AtrR homologs from other pathogenic species arguing that its importance in transcriptional regulation is maintained across evolution.

Investigating the synergistic effects of apple vinegar and deep eutectic solvent as natural antibiotics: an experimental and COSMO-RS analysis

ABSTRACT The present investigation examines the antimicrobial and antifungal characteristics of natural deep eutectic solvents (NADES) and apple vinegar in relation to a diverse array of bacterial and fungal strains. The clinical bacterial strains, including gram-negative and gram-positive, and the fungal pathogen Candida albicans, were subjected to solid medium diffusion to determine the inhibitory effects of these compounds. The results show that NADES has superior antimicrobial and antifungal action compared to apple vinegar. The observed inhibitory zones for apple vinegar and NADES varied in length from 16.5 to 24.2 and 16 to 52.5 mm, respectively. The results obtained indicate that no synergy is observed for this mixture (50% AV + 50% NADES). The range of values for bactericidal concentrations (MBC) and minimal inhibitory concentrations (MIC) was 0.0125 to 0.2 and 0.0125 to 0.4 µl/ml, respectively. Antibacterial and antifungal chemicals may be found in apple vinegar and NADES, with NADES offering environmentally safe substitutes for traditional antibiotics. Additional investigation is suggested to refine these compounds for a wide range of bacteria, which could create antimicrobial solutions that are both highly effective and specifically targeted, thereby offering extensive potential in medicine and the environment.

Powdery Mildew of Xanthium strumarium Caused by Podosphaera xanthii in central China.

Xanthium strumarium, known as cocklebur, is an annual herb and has been used in traditional Chinese medicine. In October 2020, powdery mildew-like disease signs and symptoms were observed on X. strumarium grown in a crop field, Xinxiang city, Henan Province, China (35.36076° N, 113.93467° E). The specimen (PX-XS2023) was stored in Xinxiang Key Laboratory of Plant Stress Biology. White colonies in irregular or coalesced circular shaped-lesions were abundant on both ad- and abaxial surfaces of leaves and covered up to 99 % of the leaf area. Some of the infected leaves were senesced. More than 70 % of plants (n = 130) exhibited these signs and symptoms. Conidiophores were straight or slightly curved, 55 to 160 × 11 to 13 μm composed of foot-cells, shorter cells and conidia. Conidia were ellipsoid to oval, 29 to 40 × 14 to 20 μm (n = 50), with a length/width ration of 2.0 to 2.5, containing fibrosin bodies. Dark brown to black chasmothecia were found on infected leaves. The appendages were mycelium-shaped and at the base of scattered or gregarious chasmothecia (n = 50, 70 to 120 μm in diameter). Asci were 55 to 80 × 50 to 65 μm (n=30). These morphological characteristics were consistent with those of Podosphaera xanthii (Braun and Cook 2012). The internal transcribed spacer (ITS) region and Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) region of the fungus (PX-XS2023) were amplified and sequenced with primers ITS1/ITS4 (White et al. 1990) and GAPDH1/GAPDH3R (Bradshaw et al. 2022) according to a previously reported method (Zhu et al. 2022). The resulting sequences were respectively deposited into GenBank (Accession No. MW300956 and PP236083). BLASTn analysis indicated that the sequences were respectively 99.82 % (564/565) and 100% (272/272) identical to P. xanthii (MT260063 and ON075658). The phylogenetic analysis indicated that the strain PX-XS2023 and P. xanthii were clustered into a same branch. Therefore, the causal agent of powdery mildew on X. strumarium was P. xanthii. To conduct pathogenicity assays, mature leaves of five healthy X. strumarium (height in 50 centimeters) were inoculated with fungal conidia by gently pressing surfaces of infested leaves onto leaves of healthy plants (Zhu et al. 2020). Five untreated plants served as controls. The controls and inoculated plants were separately maintained in greenhouses (humidity, 60%; light/dark, 16 h/8 h; temperature, 18°C). Eight days post-inoculation, signs of powdery mildew were detectable on inoculated plants, however, the controls were asymptomatic. Thus, the fungal pathogen was morphologically and molecularly identified and confirmed as P. xanthii. This powdery mildew caused by P. xanthii was previously reported on X. strumarium in Korea, Russia and India (Farr and Rossman, 2021). In addition, P. xanthii was recorded on X. strumarium in Xinjiang Province, China (Tai 1979). However, this is the first report of P. xanthii on X. strumarium in central China, where is around 3000 km away from Xinjiang Province with geographically differences. The sudden presence of powdery mildew caused by P. xanthii may adversely affect plant health and thus reduce medical value of X. strumarium. Therefore, the identification and confirmation of P. xanthii infecting X. strumarium enhance the knowledge on the hosts of this pathogen in China and will provide fundamental information for disease control in the future.

Take-out food enhances the risk of MPs ingestion and obesity, altering the gut microbiome in young adults

Young people are consuming large amounts of microplastics (MPs) due to the booming development of the take-out industry. To investigate the association between MPs exposure and obesity, 121 volunteers were divided into high MPs exposure (HME) and low MPs exposure (LME) according to the frequency of take-out food consumption. Fecal samples were collected for MPs detection using Raman spectra analysis, and identification of the gut microbiota was based on 16 S rDNA/ITS, while metabolite analysis was performed by LC-MS/MS. High levels of MPs and body mass index (BMI) were observed in the HME group (P < 0.05). Both the multiple linear regression (MLR) model and the binary logistic regression (BLR) (OR: 1.264, 95 % CI: 1.108–1.441, P < 0.001) analysis showed a positive correlation between MPs content and BMI. Microbial community analysis revealed that Veillonella, Alistipes and Dothideomycotes (pathogenic fungi) increased in HME participants, whereas Faecalibacterium and Coprococcus decreased. Meanwhile, analysis of stool metabolites showed that vancomycin resistance, selenocompound metabolism and drug metabolism pathways were enhanced in HME participants. These findings indicate that frequent consumption of take-out food may elevate the intake of microplastics, consequently modifying the gut microbiota and metabolites of young adults, and could represent a potential risk factor for obesity.

Alteration of β-glucan in the emerging fungal pathogen Candida auris leads to immune evasion and increased virulence

Candida auris is an emerging pathogenic yeast that has been categorized as a global public health threat and a critical priority among fungal pathogens. Despite this, the immune response against C. auris infection is still not well understood. Hosts fight Candida infections through the immune system that recognizes pathogen-associated molecular patterns such as β-glucan, mannan, and chitin on the fungal cell wall. In this study, levels of β-glucan and mannan exposures in C. auris grown under different physiologically relevant stimuli were quantified by flow cytometry-based analysis. Lactate, hypoxia, and sublethal concentration of fluconazole trigger a decrease in surface β-glucan while low pH triggers an increase in β-glucan. There is no inverse pattern between exposure levels of β-glucan and mannan in the cell wall architecture among the three clades. To determine the effect of cell wall remodeling on the immune response, a phagocytosis assay was performed, followed by quantification of released cytokines by ELISA. Lactate-induced decrease in β-glucan leads to reduced uptake of C. auris by PMA-differentiated THP-1 and RAW 264.7 macrophages. Furthermore, reduced production of CCL3/MIP-1⍺ but not TNF-⍺ and IL-10 were observed. An in vivo infection analysis using silkworms reveals that a reduction in β-glucan triggers an increase in the virulence of C. auris. This study demonstrates that β-glucan alteration occurs in C. auris and serves as an escape mechanism from immune cells leading to increased virulence.

Biocontrol of Botrytis cinerea by Streptomyces noursei C27 and preliminary identification of antimicrobial metabolites

A wide variety of soluble bioactive secondary metabolites and volatile organic compounds are produced by species of Streptomyces, making them potential candidates for controlling phytopathogenic microorganisms. In the present study, Streptomyces noursei C27, isolated from soil, was found to exhibit broad spectrum inhibitory activity against several phytopathogenic fungi. Furthermore, volatile organic compounds (VOCs) produced by S. noursei C27 exhibited total inhibition of Botrytis cinerea. An analysis of the complete genome sequence confirmed the identification of C27 as Streptomyces noursei. Liquid chromatography-tandem mass spectrometry analysis was used to characterize antimicrobial metabolites present in the fermentation broth of Streptomyces C27, that were identified as gougerotin, natamycin, nystatin, and anisomycin. Streptomyces C27 was shown to control gray mold on grape leaves and fruit in vitro, inhibiting infections by 72.5% and 71.9%, respectively. Gas chromatography-mass spectrometry analysis revealed that thirty alkenes, alcohols, esters, and alkanes were among the VOCs secreted by Streptomyces C27 and contributed to the inhibition of B. cinerea growth and development in inoculated grape leaves and fruit. The biocontrol efficacy of a wettable powder formulation of Streptomyces C27 against gray mold was tested on tomato seedlings in pot experiments and greenhouse experiment. Results indicated 61.86% and 67.25% control in the pot and field tests, respectively. In summary, Streptomyces noursei C27 has excellent potential to be a commercial biocontrol agent of plant diseases caused by pathogenic fungi, especially gray mold infections of vegetables and fruits caused by B. cinerea.