Fusarium Species Research Articles

Identification and biological characteristics of Fusarium tobaccum sp. nov., a novel species causing tobacco root rot in Jilin Province, China.

Fusarium wilt of tobacco (FWT), caused by Fusarium spp., has emerged as a severe threat to tobacco production in China. In all, 132 isolates of Fusarium were isolated from tobacco and pathogenic to tobacco-causing FWT in Jilin Province, China. In this study, we identified 7 of 132 isolates as a novel species Fusarium tobaccum sp. nov. Zhao Xie & Jie Gao, using multi-gene phylogenetic analyses of translation elongation factor (tef1), β-tubulin (tub2), calmodulin (cmdA), and RNA polymerase II second largest subunit (rpb2) genes, along with subtle morphological differences. Isolates of F. tobaccum sp. nov. were clustered in a distinct branch in the maximum parsimony phylogenetic tree generated from the sequences of tef1-rpb2-tub2-cmdA and can be distinguished from closely related species F. cugenangense, F. callistephi, and F. elaeidis. The morphological characteristics of F. tobaccum sp. nov. are distinct from other Fusarium species. F. tobaccum sp. nov. exhibits abundant aerial mycelia and pigment production on potato dextrose agar (PDA), microconidia with 0-1 septa, and macroconidia with 2-5 septa on carnation leaf-piece agar (CLA), and produces abundant chlamydospores on Spezieller Nährstoffarmer agar (SNA) and CLA. The mycelia of F. tobaccum exhibited optimal growth at a pH of 7.1 and a temperature of 23.6°C. Sucrose and NaNO3 significantly promoted the mycelial growth of F. tobaccum. PD medium was optimal for total sporulation. However, the sporulation ratios of the macrospores of F. tobaccum in PD, SN, and CMC were relatively low (0.48%, 2.51%, and 2.16%, respectively). These findings provided valuable insights into the morphological and biological characteristics of F. tobaccum.IMPORTANCEFusarium wilt of tobacco (FWT) is a prevalent issue in tobacco-growing regions globally, leading to significant losses in yield and quality. This study identified F. tobaccum sp. nov., a novel species of Fusarium causing FWT in China. The identification was based on multi-gene phylogenetic analyses and morphological characteristics. The effects of temperature, pH, carbon source, nitrogen source, medium, and light on the mycelial growth of F. tobaccum sp. nov. were determined. These findings might contribute to future research on the pathogenic mechanisms of this novel species and the development of strategies to control FWT.

Investigating the Structure of the Components of the PolyADP-Ribosylation System in Fusarium Fungi and Evaluating the Expression Dynamics of Its Key Genes

Poly(ADP-ribose) polymerase (PARP) is the key enzyme in polyADP-ribosylation, one of the main post-translational modifications. This enzyme is abundant in eukaryotic organisms. However, information on the PARP structure and its functions in members of the Fungi kingdom is very limited. In this study, we performed a bioinformatic search for homologs of PARP and its antagonist, PARG, in the genomes of four Fusarium strains using their whole-genome sequences annotated and deposited in databases. The F. graminearum PH-1, F. proliferatum ET-1, and F. oxysporum Fo47 strains were shown to possess a single homolog of both PARP and PARG. In addition, the F. oxysporum f. sp. lycopersici strain 4287 contained four additional proteins comprising PARP catalytic domains whose structure was different from that of the remaining identified homologs. Partial nucleotide sequences encoding the catalytic domains of the PARP and PARG homologs were determined in 11 strains of 9 Fusarium species deposited in all-Russian collections, and the phylogenetic properties of the analyzed genes were evaluated. In the toxigenic F. graminearum strain, we demonstrated up-regulation of the gene encoding the PARP homolog upon culturing under conditions stimulating the production of the DON mycotoxin, as well as up-regulation of the gene encoding PARG at later stages of growth. These findings indirectly indicate involvement of the polyADP-ribosylation system in the regulation of the genes responsible for DON biosynthesis.

Fusarium species associated with naturally regenerated Fagus sylvatica seedlings affected by Phytophthora

AbstractFusarium diseases in forests, especially in naturally regenerated seedlings, are poorly recognized. Recently the rapid and severe decline of natural regeneration of European beech caused by Phytophthora spp. has been observed in Poland. The diseased beech seedlings were also co-infected by Fusarium species. The aim of this study was to isolate and identify the role of Fusarium species that may play a role in the decline of beech seedlings in Poland. A total of 487 Fusarium isolates were obtained from 450 symptomatic and asymptomatic beech seedlings: 466 from symptomatic plants and 21 from asymptomatic plants. Based on comparisons for two genes and phylogenetic analysis, all Fusarium strains were separated into 14 phylogenetically distinct species belonging to four Fusarium species complexes (SC), namely the F. incarnatum-equiseti species complex (FIESC), the F. nisikadoi species complex (FNSC), the F. sambucinum species complex (FSSC), and the F. tricinctum species complex (FTSC). Fusarium avenaceum and F. paeoniae were the most frequently isolated species from both above- and below-ground organs of seedlings affected by Phytophthora. In the pathogenicity trials, the most virulent species for beech seedlings were F. avenaceum and F. sporotrichioides. However, Fusarium isolates were significantly less aggressive compared to the P. × cambivora (positive control). Our results demonstrate that beech seedlings were frequently colonized by various Fusarium species. Fusarium species do not play an important role in the reduction of naturally regenerated European beech seedlings due to their low aggressiveness.

Molecular identification of Fusarium species in commercial vanilla and crop wild relatives in Colombia.

Vanilla is an economically important crop for low-lying humid tropical regions, but cultivated plants face serious phytosanitary problems. Fusarium wilt is a devastating disease affecting vanilla crops, caused by the fungal pathogens Fusarium oxysporum f. sp. vanillae (Fov) and F. oxysporum f. sp. radicis-vanillae (Forv), part of the F. oxysporum species complex (FOSC). We characterized 29 fungal isolates from a vanilla crop and crop wild relatives (CWR) using molecular (EF1-α and ITS-rRNA loci) and morphological traits. Fusarium was the predominant genus, followed by Colletotrichum and Clonostachys. Four Fusarium species were identified: F. oxysporum (37.9%), Fusarium solani (20.7%), Fusarium pseudocircinatum (13.8%) and Fusarium concentricum (10.3%). The latter three species were isolated only from CWR and may represent latent pathogens. Fov was isolated from both the crop and CWR, while a Forv-affiliated isolate was also found in a vanilla crop, marking the first report in the neotropical region. The EF1-α locus provided greater genotype resolution, as well as having reference sequences for Forv. However, the fungal barcode ITS locus is widely applied. We recommend the continued use of both loci for Fusarium diagnosis in vanilla to facilitate early detection and the development of effective integrated crop management strategies.

Recent Updates on the Secondary Metabolites from Fusarium Fungi and Their Biological Activities (Covering 2019 to 2024)

Fusarium species are commonly found in soil, water, plants, and animals. A variety of secondary metabolites with multiple biological activities have been recently isolated from Fusarium species, making Fusarium fungi a treasure trove of bioactive compounds. This mini-review comprehensively highlights the newly isolated secondary metabolites produced by Fusarium species and their various biological activities reported from 2019 to October 2024. About 276 novel metabolites were revealed from at least 21 Fusarium species in this period. The main metabolites were nitrogen-containing compounds, polyketides, terpenoids, steroids, and phenolics. The Fusarium species mostly belonged to plant endophytic, plant pathogenic, soil-derived, and marine-derived fungi. The metabolites mainly displayed antibacterial, antifungal, phytotoxic, antimalarial, anti-inflammatory, and cytotoxic activities, suggesting their medicinal and agricultural applications. This mini-review aims to increase the diversity of Fusarium metabolites and their biological activities in order to accelerate their development and applications.

Biofilm Formation in Clinical Isolates of Fusarium

Many microbial pathogens form biofilms, assemblages of polymeric compounds that play a crucial role in establishing infections. The biofilms of Fusarium species also contribute to high antifungal resistance. Using our collection of 29 clinical Fusarium isolates, we focused on characterizing differences in thermotolerance, anaerobic growth, and biofilm formation across four Fusarium species complexes commonly found in clinical settings. We investigated the role of carbon sources, temperature, and fungal morphology on biofilm development. Using fluorescence microscopy, we followed the stages of biofilm formation. Biofilms were screened for sensitivity/resistance to the antifungals voriconazole (VOR), amphotericin B (AmB), and 5-fluorocytosine (5-FC). Our findings revealed generally poor thermotolerance and growth under anaerobic conditions across all Fusarium species. VOR was more effective than AmB in controlling biofilm formation, but the combination of VOR, AmB, and 5-FC significantly reduced biofilm formation across all species. Additionally, Fusarium biofilm formation varied under non-glucose carbon sources, highlighting the species’ adaptability to different nutrient environments. Notably, early stage biofilms were primarily composed of lipids, while polysaccharides became dominant in late-stage biofilms, suggesting a dynamic shift in biofilm composition over time.

Antifungal Activity of Mexican Oregano (Lippia graveolens Kunth) Extracts from Industrial Waste Residues on Fusarium spp. in Bean Seeds (Phaseolus vulgaris L.)

Food security is essential to ensure everyone can access sufficient nutritious food. Cereals and legumes are fundamental foods worldwide. Phaseolus vulgaris L., the common bean, is an essential staple food in many nations worldwide. However, it is vulnerable to fusariosis, a disease caused by the fungus Fusarium spp. that can significantly decrease crop quality and yield. To combat plant diseases, industrial residues and plant residues are valuable due to their bioactive compounds with biotechnological applications. This study proposes using ethanolic extracts with phytochemical compounds, such as flavonoids, different from those reported in essential oils, to reduce the growth of Fusarium species both in vitro and in vivo. Industrial residues that are produced after extracting essential oils offer a promising alternative to develop organic biopesticides, promoting more sustainable and environmentally friendly agriculture.

Mycotoxigenic Fusarium species and zearalenone concentration in commercial maize kernels in northern Ghana.

The fungal genus Fusarium contains many toxigenic pathogens of maize with associated yield losses, reduction of grain quality, and accumulation of mycotoxins in harvested grains. To determine zearalenone (ZEN) concentration and identify the various Fusarium species in commercial maize grains, a survey of 75 maize samples, collected from 11 market centers in the five regions in northern Ghana was identified based on morphological characteristics, sequence analysis of the internal transcribed spacer region, and polymerase chain reaction using species-specific primers. ZEN levels were determined using HPLC. ZEN contamination was recorded in 33.3% of the maize samples, with concentrations ranging from 0.61 to 3.05µg/kg. Based on VERT1/2 and TEF 1-α sequencing, F. verticillioides was the most prevalent species in the studied samples: 40.35% from the Upper East Region, 28.07% from the North East Region, 19.30% from the Upper West Region, 10.53% from the Savannah Region, and 1.75% for the Northern Region. Other fungal species found were F. equiseti and F. solani. A higher number of the Fusarium isolates were found in white maize (609 isolates from 27 samples) compared to yellow maize (225 isolates from 23 samples).

Fusarium and Neocosmospora Species Associated with the Decline of Metasequoia glyptostroboides in China.

During surveys conducted in 2020, severe symptoms associated with death and decline were observed on >30-year-old Metasequoia glyptostroboides (Chinese redwood) trees in the shelter-forests along Yangtze River in Jingzhou city, Hubei province, China. A previous study showed that Phytophthora acerina was one of the causal agents of the decline of the Chinese redwood. In this study, a total of 147 fungal isolates were obtained from the diseased roots and xylem of trunks of declining M. glyptostroboides trees. Through morphology and multi-locus phylogenetic analysis, these isolates were identified as eight species belonging to the genera Fusarium and Neocosmospora including F. fujikuroi, F. irregulare, F. odoratissimum, F. reticulatum， N. falciformis, N. keratoplastica, N. solani, and N. tonkinensis. Single inoculation and co-inoculation with P. acerina assays of these Fusarium and Neocosmospora species were then performed to test pathogenicity on three-year-old seedlings of M. glyptostroboides. Lesions (i.e., on seedling stems) caused by species of the genera Neocosmopora and Fusarium were smaller than those caused by P. acerina. Co-inoculation of F. fujikuroi and P. acerina, as well as the co-inoculation of F. reticulatum and P. acerina caused larger lesions than inoculations with P. acerina alone. All these species of Fusarium and Neocosmospora were shown to have the potential to be pathogenic to M. glyptostroboides. This study provided evidence that the decline of M. glyptostroboides in Jingzhou is a disease complex.

Impact of Harvest Delay and Barley Variety on Grain Nutritional Composition and Mycotoxin Contamination

This study investigated the effects of delayed harvesting, varying meteorological conditions, and barley variety on Fusarium spp. infection rates, nutritional composition, and mycotoxin contamination in barley grains. Field experiments were conducted from 2020 to 2022 and involved two barley varieties: ‘Laureate’ for malting and ‘Luokė’ for feed. The results indicated that the dominant Fusarium species isolated were F. avenaceum, F. culmorum, F. poae, F. sporotrichioides, F. tricinctum, and F. equiseti. These tended to increase in number with delayed harvest times and were more prevalent during harvest periods of higher precipitation (p < 0.05). Malting barley had higher starch and lower protein content compared to feed barley (p < 0.05). Delayed harvesting generally increased dry matter, crude fat, and crude ash contents while decreasing crude protein, zinc, and iron contents (p < 0.05). Mycotoxin analysis revealed significant differences under specific weather conditions. HT-2 toxin levels were higher under slightly warmer and wetter conditions during flowering, with harvest conditions similar to the long-term average. Zearalenone levels increased with dry, warm growing seasons followed by rainy harvests. Nivalenol and enniatin levels increased with rainy growing seasons and dry, warm harvests. Deoxynivalenol concentrations did not reach the limit of quantification throughout the study. No consistent trend was observed for higher contamination in any specific barley variety (p > 0.05). The strongest correlations between mycotoxins and nutritional value indicators were observed with less-studied mycotoxins, such as nivalenol and enniatins, which exhibited negative correlations with crude protein (p < 0.01), crude fat (p < 0.05), and zinc (p < 0.01), and positive correlations with crude ash (p < 0.05) and phosphorus (p < 0.01).

A Diagnostic Guide for Fusarium Fruit Rot of Pumpkin and Winter Squash

Fusarium fruit rot caused by Fusarium solani f. sp. cucurbitae is an important postharvest disease impacting the global production and storage of pumpkins and winter squash ( Cucurbita spp.). The pathogen infects fruit through wounds, causing water-soaked lesions that may become sunken, coalesce, and be covered by fine mycelial growth. F. solani is soilborne and can survive long term in soil and plant debris. Storage rots impact several Cucurbita spp. grown for long-term storage. F. solani f. sp. cucurbitae has two races and is the most commonly found Fusarium species infecting cucurbits. Identification includes morphologic and PCR-based methods. This guide outlines taxonomy, symptoms, isolation, and epidemiology and provides methods to identify the pathogen.

Comparative genomics of Fusarium species causing Fusarium ear rot of maize.

Fusarium ear rot (FER), caused by the fungal pathogen Fusarium verticillioides, stands as one of the most economically burdensome and pervasive diseases affecting maize worldwide. Its impact on food security is particularly pronounced due to the production of fumonisins, toxic secondary metabolites that pose serious health risks, especially for livestock. FER disease severity is complex and polygenic, with few resistance (R) genes being identified for use in breeding resistant varieties. While FER is the subject of several breeding programs, only a few studies have investigated entire populations of F. verticillioides with corresponding virulence data to better understand and characterize the pathogenomics. Here, we sequenced and compared the genomes of 50 Fusarium isolates (43 F. verticillioides and 7 other Fusarium spp.) that were used to inoculate a diverse maize population. Our objectives were to elucidate the genome size and composition of F. verticillioides, explore the variable relationship between fumonisin production and visual disease severity, and shed light on the phylogenetic relationships among the isolates. Additionally, we conducted a comparative analysis of the nucleotide variants (SNPs) and the isolates' effectoromes to uncover potential genetic determinants of pathogenicity. Our findings revealed several promising leads, notably the association of certain gene groups, such as pectate lyase, with disease severity. These genes should be investigated further as putative alleles for breeding resistant maize varieties. We suggest that, beyond validation of the alleles identified in this study, researchers validate each phenotypic dataset on an individual basis, particularly if considering fumonisin concentrations and when using diverse populations. Our study underscores the importance of genomic analysis in tackling FER and offers insights that could inform the development of resilient maize cultivars. By leveraging advances in genomics and incorporating pathogen populations into breeding programs, resistance to FER can be advanced.

A comprehensive review of integrated management strategies for damping-off disease in chili.

Damping-off disease in chili (Capsicum annum L.) cultivation is a significant global issue, severely affecting seeds, seedlings, and young plants, regardless of the location of cultivation, whether in greenhouses or open fields. Despite chili being a widely popular vegetable used in various cuisines globally, farmers face challenges in meeting the growing demand due to the extensive damage caused by this disease, ranging from 20 to 85%. The shelf life and quality of mature pods are also severely affected. Damping-off disease is mainly caused by soil-borne fungus from the Pythium species, with additional contributions from Phytophthora, Fusarium, and Rhizoctonia species. These pathogens' adaptability to diverse environmental conditions and resistance to synthetic fungicides make controlling damping-off on a commercial scale challenging. However, integrated disease management has shown promising results as a remedial approach. In this review, we discuss the current state of chili diseases, the nature of the pathogens causing damping-off, the epidemiology of the disease, and various control mechanisms. In this review, we broadly discuss the current state of chili diseases, the nature of the pathogens causing damping-off, the epidemiology of the disease, and various control mechanisms. Furthermore, we highlight the importance and efficacy of integrated disease management techniques, along with future prospects in unexplored areas, such as host-pathogen interaction and sustainable disease control measures. The information in this review aims to assist chili growers in understanding the epidemiology and management of damping-off in chili cultivation.

Stalks and roots are the main battlefield for the coevolution between maize and Fusarium verticillioides.

Fusarium species are the dominant cause of maize ear rot, but they also inflict serious damage to the roots and stalks. Theoretically, the organ where the host interacts with the pathogen most frequently should exhibit the highest degree of symptom-genotype correlation. Because that symptom-genotype correlation is an indicator reflecting the degree of coevolution between pathogen and its hosts. We wonder which organ is the main battlefield for the antagonism between maize and Fusarium. For this purpose, 43 isolates of Fusarium were isolated from infected maize ears. Fusarium verticillioides and F. graminearum are the two dominant pathogens, accounting for 44% and 30%, respectively. Furthermore, 14 elite maize inbreds were exposed to 43 Fusarium isolates and the symptoms of ear rot, stalk rot and root rot were investigated. In general, symptoms caused by F. graminearum were significantly more severe than those caused by other Fusarium species. Surprisingly, the genotype of F. verticillioides showed a strong correlation with stalk and root rot, but not with ear rot. Accordingly, our study may provide the first evidence that the stalk and root of maize, rather than the ear, is the main battlefield for the coevolution between maize and F. verticillioides.

Fusarium species associated with Bakanae Disease of Rice in Bangladesh.

Bakanae disease has become a serious threat for sustainable rice production in Asian countries including Bangladesh. Fusarium species are important seedborne pathogens that cause bakanae disease of rice. Typical bakanae symptomatic samples were collected through a series of sampling conducted in several districts of Bangladesh for 4 consecutive years from 2019 - 2022. The pathogens were confirmed using morphological characteristics, DNA sequences, and phylogenetic analyses of two genes, namely, translation elongation factor 1-alpha (TEF1-α), and RNA polymerase subunit II (RPB2). A total of 121 Fusarium isolates were recovered from diseased rice samples at different geographical locations. From the phylogenetics analyses of TEF1-α and RPB2 gene sequences coupled with morphological characterization revealed that the collected isolates belonged to five species viz. F. fujikuroi (75.2% isolation frequency), F. incarnatum (17.35%), F. commune (4.95%), F. verticillioides (1.65%), and F. proliferatum (0.82%). Phylogenetic analysis also showed that 28 representative strains were attributed to five species. Finally, four Fusarium spp. F. fujikuroi, F. commune, F. verticillioides and F. proliferatum were found to be pathogenic under virulence assays of the isolates. The pathogenicity test results demonstrated that F. fujikuroi caused typical symptoms of bakanae, leaf elongation and chlorosis, whereas F. proliferatum and F. verticillioides only caused stunting of seedlings and F. commune caused wilt and root rot. F. incarnatum was found to be associated with bakanae disease of rice, however their pathogenicity could not be established. This study provides insight into the diversity and pathogenicity of Fusarium populations associated with bakanae disease in Bangladesh, which will help in formulating effective strategies and policies for better control of the bakanae disease.

First Report of Fusarium falciforme Causing Fusarium Wilt on pepper in Hainan, China.

Pepper (Capsicum annuum L.) is a significant vegetable crop, valued for its nutritional and economic importance (Pang et al. 2023). Pepper cultivation in China accounts for about 8-10% of the total vegetable planting area, contributing an output value of approximately 250 billion yuan. This makes pepper the leading vegetable in terms of both planting area and economic value. In December 2023, a total of 70% disease incidence of Fusarium wilt was observed in a 1200 m² pepper seed breeding base in Sanya City, Hainan Province, China (18°38'60″ N, 109°16'51″ E). Symptoms initially appeared as wilting on upper leaves. Subsequently, the base of the stem started to necrosis, browning, and gradually spreading upward along the stem. As the lesions expanded, the whole plant gradually wilted and died. Ten diseased plants were randomly selected from the most severely affected area (667 m²). Diseased tissues (5 mm²) were subsequently removed from the lesion edges of these plants, surface sterilized in 75% ethanol for 30 s, and rinsed with sterile distilled water three times, finally cultured on potato dextrose agar (PDA) at 25 °C. Six fungal isolates were obtained using the single-spore isolation method (HN-01 to HN-06). Colonies produced white aerial mycelia with apricot pigments in the PDA medium. The spore morphology and size were observed and measured using synthetic nutrient-poor agar (SNA) medium. Macroconidia were hyaline, slightly curved in shape with 3 or 4 septa, measuring 28.6 to 41.4 × 3.2 to 6.2 μm (av. = 34.8 ± 3.32 × 4.6 ± 0.85 um, n = 20). Microconidia were elongated, oval with 0 or 1 septum, and measured 11.2 to 16.8 × 2.6 to 5.8 μm (av. = 13.5 ± 1.47 × 4.12 ± 1.03 um, n = 20). Chlamydospores were spherical, terminal or intercalary, solitary or chain-forming, with diameters ranging from 2.8 to 10.5 um (av. = 5.8 ± 2.31 um, n = 20). For molecular identification, genomic DNA from all six isolates was extracted using the cetyl trimethyl ammonium bromide (CTAB) method, and the internal transcribed spacer of rDNA (ITS), translation elongation factor 1-α (EF1-α), and RNA polymerase II beta subunit (RPB2) regions were amplified and sequenced using the primers ITS1/ITS4, EF-1/EF-2, and RPB2-5F/7cR (White et al. 1990; O'Donnell et al. 2010). The sequences were deposited in GenBank (ITS: PP779839, PP779840, PP779841, PP779842, PP779843, PP779844; EF1-α: PP797138, PP797139, PP797140, PP797141, PP797142, PP797143; RPB2: PP797144, PP797145, PP797146, PP797147, PP797148, PP797149). The sequences of all three genes showed 99 to 100% similarity with Fusarium falciforme and other closely related Fusarium species (ITS: PP735125, EF1-α: OP163897 and RPB2: MF467484). A maximum likelihood phylogenetic tree was constructed based on the ITS, EF1-α, and RPB2 sequences of all isolates, along with other closely related Fusarium species. Based on morphological and phylogenetic characteristics, all isolates were identified as F. falciforme (Xu et al. 2023; Wang et al. 2023). Ten Pepper inbred line A23-41 (5 for the inoculation treatment and 5 for the control) were tested for pathogenicity using three representative isolates: HN-01, HN-02, and HN-03. A total of 20 ul of spore suspension with concentration 106 spores/ml was injected near the soil surface of the stem, while the control treatment was inoculated with 20 μl of sterile water. The plants were placed in a climatic chamber at RH80-90% and 25/20 °C (day/night) after inoculation. The experiment was repeated three times. After 10 days, Inoculated plants stem developed necrosis, browning, while the control group remained asymptomatic. The fungus reisolated from the artificially infected stems was identified through EF1-α and RPB2 sequence analysis as F. falciforme, thus fulfilling Koch's postulates. Fusarium falciforme has been previoulsy reported as causing various diseases on different hosts in several countries, including Korea (Kang et al., 2024), Malaysia (Balasubramaniam et al., 2023), and Mexico (Payán-Arzapalo et al., 2024). To the best of our knowledge, this is the initial report demonstrating that F. falciforme causes Fusarium wilt on peppers in China. The study results can provide the basis for future research on the occurrence, prevention, and management of this disease.

The effects of fumonisin B1 on intercellular communications and miRNA modulations: Non-genotoxic carcinogenesis mechanisms in human kidney cells

Fumonisin B1 (FB1), which is produced by Fusarium species, is one of the most prevalent mycotoxins known to exert several toxic effects, particularly nephrotoxicity. While its genotoxic carcinogenic mechanisms have been extensively studied, its influence on non-genotoxic pathways including intercellular communication and microRNA (miRNA) regulation remain underexplored. The present study investigates the effects of FB1 on gap junctions, miRNA expression profiles, and their relationship in human kidney cells (HK-2 and HEK293). Both cell lines showed increased apoptosis rates at 50 and 100 µM, while FB1 exposure significantly reduced gap junctional intercellular communication (GJIC) and decreased the expression levels of related genes, including Cx43, Cx45, e-cadherin, Cadherin-2, and β-catenin. After FB1 treatments alteration on the regulation of miRNAs including let-7a-5p, miR-125a-5p, miR-222–3p, miR-92a-3p, let-7b-5p, let-7e-5p, miR-21–5p, miR-155–5p, let-7i-5p, let-7d-5p, let-7f-5p, miR-181b-5p, miR-15b-5p, miR-23b-3p, miR-20b-5p, miR-196a-5p miRNAs have been shown. Let-7a-5p was selected among the altered miRNAs to elucidate the relationship between miRNAs and GJIC after FB1 exposure as it is one of the common miRNAs that changes in both cell lines and one of its target genes is Cx45, which is an important gene for GJIC. However, transfection analysis did not show any differences, resulting in Cx45 not being a direct target of let-7a-5p in HK-2 and HEK-293 cells. Through comprehensive analysis, we elucidated that FB1's impact on intercellular signaling cascades and its regulatory role on miRNA expression profiles, offering valuable insights into carcinogenesis beyond traditional genotoxic paradigms. Understanding these mechanisms is crucial for elucidating the mechanisms of FB1-induced toxicity.

Fusarium Species Shifts in Maize Grain as a Response to Climatic Changes in Poland

Maize, along with wheat and rice, is the most important crop for food security. Ear rots caused by Fusarium species are among the most important diseases of maize. The distribution of Fusarium species provides essential epidemiological information for disease management. The effect of weather conditions, climate change and geographic localization on the Fusarium population in Poland was evaluated between 2015 and 2018. Grain samples (n = 233) were collected from hybrids at 16 locations (L1–L16). The differences in altitude between locations ranged from 39 to 243 m above sea level, longitude varied between 15°55′ and 23°12′ E, and latitude spanned from 50°12′ to 54°01′ N. Isolates were identified using molecular techniques. The highest Fusarium species frequency was recorded for 2016 (30.70%) and 2017 (28.18%), and the lowest for 2018 (5.36%). F. verticillioides and F. temperatum were the most frequent. Altitude has an effect on F. vericillioides frequency: F. graminearum showed a negative correlation with both latitude and longitude. In Polish conditions, from silking to harvesting, the number of days with higher precipitation and lower temperatures is associated with an increased frequency of F. verticillioides, F. temperatum, F. graminearum and F. avenaceum. This suggests that the Fusarium presence in Poland is significantly influenced not only by climate change but also by extreme weather changes.

A single-center study on the distribution and shifting trend of infectious keratitis pathogens from 2018 to 2022

Objective: To investigate the pathogen species, composition, and distribution characteristics of infectious keratitis pathogens in Shandong Province and its surrounding areas. Methods: In this cross-sectional study, patients with keratitis who underwent corneal sampling and microbiological culture at the Shandong Eye Hospital from January 1, 2018 to December 31, 2022 were included. Under topical anesthesia, the edge of the lesion was scraped by an experienced physician. The samples were inoculated on blood agar and Sabouraud dextrose agar plates, separately for bacterial and fungal culture and identification. If necessary, the samples were inoculated on a non-nutrient agar medium with Escherichia coli for Acanthamoeba culture. Bacterial isolates were identified using Vitek 2 compact or matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Fungal isolates were identified based on morphological characteristics or sent to a company for sequencing in cases of difficult identification. The epidemiological data of the patients, pathogen species and number (counting as 1 strain if the same strain was isolated from multiple corneal specimens of the same patient), culture positivity rate, and seasonal distribution were recorded. Differences in pathogen positivity rates among different seasons were analyzed using the chi-square test. Results: Among the 4, 024 patients with infectious keratitis during the study period, there were 2 510 males (62.3%) and 1 514 females (37.6%), aged from 46 days to 94 years. Positive microbial culture results were achieved in 2, 363 patients (58.7%), including 906 cases (38.3%) with bacterial positivity, 1 231 cases (52.1%) with fungal positivity, 28 cases (1.2%) with Acanthamoeba positivity, and 198 cases (8.4%) with mixed fungal and bacterial infections. A total of 2 561 strains were isolated, including 1 104 bacterial strains. The most common bacteria were coagulase-negative Staphylococcus spp. (623/1 104, 56.4%), followed by Streptococcus spp. (131/1 104, 11.9%) and Pseudomonas aeruginosa (68/1 104, 6.2%). The most common fungi were Fusarium spp. (634/1 429, 44.4%), followed by Aspergillus spp. (279/1 429, 19.5%) and Alternaria spp. (229/1 429, 16.0%). Bacterial keratitis was more common in summer and autumn, while fungal keratitis was more common in autumn and winter. Conclusions: Among infectious keratitis cases in Shandong Eye Hospital, Fusarium species were predominant fungal pathogens, while coagulase-negative Staphylococcus predominated in bacterial pathogens. Both fungal and bacterial corneal infections showed seasonal variations.

Susceptibility of Aphis craccivora (Hemiptera: Aphididae) to three entomopathogenic Fusarium species

The black aphid (Aphis craccivora) is an insect pest that can cause significant losses to different agricultural crops. Entomopathogenic fungi can be good options for controlling this insect. Fusarium species have shown promising results in the biological control of several agricultural pests, mainly of the order Hemiptera. This study investigated the susceptibility of A. craccivora to 27 Fusarium isolates, distributed among F. sulawesiense (4), F. pernambucanum (6) and F. caatingaense (17). The viability of the conidia of all isolates was assessed by measuring their germination rate. Pathogenicity tests were conducted at 10⁷ conidia/mL, and the best-performing isolate was further tested at different concentrations (10⁴ to 10⁸ conidia/mL). Data were analyzed using ANOVA, Tukey's test at 5 %, and R for calculating lethal times (LT50,90) and lethal concentrations (LC50,90). All isolates had viable conidia with germination rates between 92.67 % and 100 %. Mortality rates ranged from 17.22 % to 90.23 %. F. pernambucanum URM 7559 had the shortest lethal times (LT50 of 2.24 days and LT90 of 4.42 days), followed by F. sulawesiense URM 7555 (LT50 of 2.35 days and LT90 of 4.77 days) and F. caatingaense with LT50 of 3.93 days for URM 6784 and LT90 of 8.27 days for URM 6807. The three Fusarium species tested, especially F. pernambucanum, showed promise in the biological control of A. craccivora. Although the results are promising, additional studies are needed to evaluate the safety, field efficacy and environmental impacts of Fusarium use, focusing on the interaction with the agricultural ecosystem and the risks to non-target organisms.