Search Results (120)

Rice spikelet rot disease (RSRD) affects the production and market price of rice, and can be harmful to humans and livestock. In this study, 51 strains of Fusarium spp. were isolated from rice spikelets in the Lin’an, Yuhang, and Fuyang regions. The isolates comprised four composite species: Fusarium incarnatum-equiseti species complex (FIESC), Fusarium asiaticum species complex (FSAMSC), Fusarium fujikuroi species complex (FFSC), Fusarium commune species complex (FNSC), and five species of Fusarium spp. (F. luffae, F. sulawesiense, F. asiaticum, F. fujikuroi, and F. commune). The separation rate of F. sulawesiense was the highest (41.2%), followed by F. asiaticum at 37.3%. The results of this study, compared with those of other studies, found that the newly discovered species of Fusarium spp. associated with RSRD were FSAMSC (F. asiaticum) and FNSC (F. commune). Temperature is one of the important factors causing RSRD; the optimal growth temperature for F. sulawesiense and F. commune was 30 °C, and the optimal growth temperature for other species was 25 °C. A high temperature of 35 °C did not inhibit the growth of Fusarium, as F. commune and F. fujikuroi could grow at this temperature. At 20–30 °C, the growth rate of F. asiaticum was higher than those of other strains. To determine whether the occurrence of RSRD is related to the correlation between Fusarium and other fungi in rice spikelets under different health conditions, the genetic diversity of fungi in rice spikelets was analyzed by amplicon Internal Transcribed Spacer (ITS) sequencing, and the correlations between strains of Fusarium spp. were measured. The results showed that the fungal diversity of diseased rice spikelets (RD) was higher than that of relatively healthy rice spikelets (RH). Curvularia spp., which was affected by the condition of the spikelets, was negatively correlated with Fusarium spp. in RH and positively correlated with Fusarium spp. in RD. Therefore, Fusarium spp. and Curvularia spp. can jointly cause the occurrence of RSRD. The results of the study are significant for understanding the occurrence of RSRD and formulating prevention and control measures. Full article

Foshou yam (Dioscorea esculenta) is a tuber food crop in China. It is a rare species of the yam family and known for its high nutritional value. From 2019 to 2021, tuber rot was observed in Foshou yam in Wuxue, Hubei Province, China. Fungal strains were isolated from diseased tubers, and ten representative strains were identified based on microscopical characterization and multi-locus phylogenetic analysis. A total of five different species were identified, including Curvularia geniculata, Curvularia muehlenbeckiae, Fusarium commune, Penicillium oxalicum, and Penicillium sclerotigenum. Pathogenicity test revealed that these fungi are the pathogens of tuber rot in Foshou yam. Among them, P. oxalicum exhibited the strongest pathogenicity. To our knowledge, this is the first report of tuber rot in D. esculenta caused by these five species worldwide. This study provides important information for the future management of tuber rot in Foshou yam. Full article

Background: Acyl-CoA oxidase (ACX), a ubiquitous eukaryotic enzyme, catalyzes the initial steps of fatty acid β oxidation and plays an important role in the biosynthesis of jasmonic acid (JA). At present, no studies have been reported on ACX family members of maize and their function in disease resistance. Objectives: This study aims to lay a foundation for clarifying the functions of ACX family genes in maize growth, development, and stress response by conducting a genome-wide identification of ACX family genes in maize, analyzing the expression characteristics of these genes in maize growth and development, hormone treatment and response to biotic and abiotic stresses, and exploring the functions of key genes in the maize disease resistance process through the use of mutants. Methods: ProtParam, TBtools, MEME, MEGA, and IBS tools were used to identify maize ACX family genes and analyze the physicochemical properties of their proteins, chromosome location, phylogenetic relationships among family members, conserved domains, conserved motifs, and cis-acting elements. Meanwhile, the expression patterns of maize ACX family genes in different tissues and their expression patterns under abiotic and biotic stresses were studied by using the data from the maize GDB database and qRT-PCR technology. Moreover, the mutants of ZmACX1, ZmACX3, ZmACX4, and ZmACX5 genes were obtained, and the disease resistance of the mutants was detected to further determine the functions of ACX genes in the maize disease resistance process. This study identified maize ACX family genes using bioinformatics methods. Results: We discovered that six ACX genes in the maize genome are distributed across four different chromosomes. Cluster analysis further classified these genes into three subfamilies. All maize ACX genes possess a conserved ACOX domain, and their promoter regions are enriched with cis-acting elements associated with heat stress and the plant hormone response. Under various tissue, biotic, and abiotic stress conditions, as well as treatments with methyl jasmonate (MeJA) and salicylic acid (SA), the expression levels of maize ACX family genes exhibited significant differences. Notably, the expression levels of ZmACX1, ZmACX3, ZmACX4, and ZmACX5 were significantly up-regulated following stress and pathogen infection, suggesting their involvement in maize growth, development, and disease resistance. To elucidate the function of these genes in maize disease resistance, the resistance of ZmACX1, ZmACX3, ZmACX4, and ZmACX5 mutants to Cochliobolus heterostrophus, Curvularia lunata, and Fusarium graminearum were further examined. The results revealed that compared to the wild-type B73, the lesion area of the mutants was significantly increased after inoculation with pathogens. This directly demonstrated the crucial role of these genes in maize resistance to C. heterostrophus, C. lunata, and F. graminearum. Conclusions: In summary, this study systematically identified maize ACX family genes, and thoroughly investigated their expression patterns and functions in maize disease resistance. Our findings provide valuable insights into the comprehensive understanding of the function and mechanism of maize ACX family genes. Full article

Saponins from leaves of Quillaja lancifolia, a native species from southern Brazil, show potent immunoadjuvant activity in experimental vaccine formulations. The accumulation of the immunoadjuvant saponin fraction QB-90 is induced in cultured leaf disks and seedlings by several stresses and stress signaling molecules, such as osmotic agents, salicylic acid, jasmonic acid, mechanical damage, ultrasound, UV-C radiation, and high light irradiance. These observations suggest a role in plant defense. To further examine this possibility, an investigation of the potential inhibitory role of Q. lancifolia saponins on plant and human pathogenic fungi and two herbivore models was carried out. The screening tests showed that saponin-rich fractions, particularly QB-90, were able to significantly inhibit the growth of Bipolaris micropus, Curvularia inaequalis, Fusarium incarnatum, and Cryptococcus gattii R265. The same metabolites acted as deterrents against the generalist mollusk and insect herbivores Helix aspersa and Spodoptera frugiperda, respectively. Significant reductions in consumption of leaf area and larvae body weight were recorded. Taken together, these data indicate a role for Q. lancifolia saponins in plant defense against diverse herbivores and fungi, having potential as a natural pest control agent and/or as a molecular platform for the development of new environmentally friendly biocide molecules. Full article

Laccase production was evaluated in 108 fungal isolates recovered from the eastern coast of Saudi Arabia, a critical element in environmental biodegradation and biotransformation. The most active isolate was identified as Curvularia lunata MLK46 (GenBank accession no. PQ100161). It exhibited maximal productivity at pH 6.5, 30 °C, and incubation for 5 d, with 1% sodium nitrate and 1% galactose as the preferred nitrogen and carbon sources, respectively. Productivity was enhanced by NaCl, CuSO₄, and FeCl₃ supplementation, with a maximum at 0.3 mM, 0.2 mM, and 61.7 mM concentrations, respectively. Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) for the purified enzyme through diethylaminoethyl (DEAE)-Sepharose chromatography revealed a prominent band at 71.1 kDa with maximum activity at pH 6 and stability at pH 6–9. Furthermore, it was optimally active at 50 °C and thermally stable at 50–80 °C with a half-life time (T_1/2) of 333.7 min to 80.6 min, respectively. Its activity was also enhanced by many metallic ions, especially Fe³⁺ ions; however, it was inhibited by Hg²⁺ and Ag⁺ ions. The enzyme demonstrated significant degradation of specific substrates such as 2,2’-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), guaiacol, o-dianisidine, and 2,6-dichlorophenol, with a kinetic efficiency constant which ranged from 40.95 mM⁻¹ s⁻¹ to 238.20 mM⁻¹ s⁻¹. UV spectrophotometry confirmed efficient oxidation peaks by electron transition against guaiacol (at 300 nm), o-dianisidine (at 480 nm), ABTS (at 420 nm), and 2,6-dichlorophenol (at 600 nm). The results collectively demonstrate the potential of laccase from C. lunata MLK46 as a promising agent for the effective biodegradation of several industrial pollutants under extreme conditions. Full article

Laccases are synthesized by a diverse range of fungi. Nevertheless, despite the industrial significance of laccases, the regulatory mechanism governing laccase production has been relatively understudied. This research aims to explore the regulatory function of the methyltransferase CcLaeA in laccase biosynthesis using the newly isolated fungal strain Curvularia clavata J1. Through CRISPR-Cas9-mediated gene disruption, the deletion of CclaeA led to a 1.5-fold increase in extracellular laccase activity in the ΔCclaeA mutant when compared to the wild-type strain. This finding indicates that CcLaeA functions as a transcriptional repressor of laccase biosynthesis. Transcriptomic analysis demonstrated that CcLaeA does not directly regulate the expression of laccase genes. Instead, it modulates genes associated with hydrolases and peptidases. This modulation potentially reduces the enzymatic degradation of laccase at the protein level. This study significantly enhances our understanding of fungal laccase regulation. By establishing a connection between the deletion of CclaeA and the improvement of enzyme stability and activity, this research offers practical insights for engineering fungal strains to optimize laccase yields for bioremediation and biofuel applications. Furthermore, the integration of targeted gene knockout with multi-omics validation sets up a methodological framework for investigating regulatory networks in non-model fungi. This framework is expected to accelerate the development of sustainable biocatalysts, thereby contributing to the advancement of biotechnology in various industrial sectors. Full article

Seven previously undescribed terpenoids, including five prenylaromadendrane-type diterpenes euphraticanoids N–R (1–5) and two aromadendrane-type sesquiterpenes, euphraticanoids S and T (6 and 7), were isolated from Populus euphratica resins. Their structures, including their absolute configurations, were elucidated by HRESIMS and spectroscopic analysis, ECD calculations, and crystallographic methods. In addition, an evaluation of the fungicidal activities of compound 1 was carried out, resulting in the discovery of 1 as a fungicidal candidate lead compound with an EC₅₀ of 15.7 and 68.6 mg/L against Curvularia mebaldsii and Fusarium graminearum, respectively. Full article

Stem blight is a significant disease affecting blueberries worldwide, caused by various pathogens. This study investigated stem blight disease in Ji’an, Jilin Province, China. Fungi isolated from diseased stems were identified as Colletotrichum temperatum, Curvularia austriaca, and Diaporthe unshiuensis based on morphological characters and multi-locus phylogenetic analyses using the internal transcribed spacer (ITS) region, glyceraldehyde 3-phosphate dehydrogenase (gapdh), chitin synthase (chs), actin (act), β-tubulin (tub2), the translation elongation factor 1-alpha (tef1-α), calmodulin (cal), and histone 3 (his3) regions. Pathogenicity test was conducted on detached green blueberry shoots, all shoots inoculated by mycelium plugs presented necrotic lesions with dark brown margins, while the control (PDA plugs) group did not show any symptoms. Koch’s postulates were confirmed by re-isolating the inoculated pathogen from the disease symptoms. The study provides three new host–pathogen records of fungi associated with blueberry stem blight. Full article

Corn (Zea mays L.) productivity is often compromised by phytosanitary challenges, with fungal disease like Curvularia leaf spot being particularly significant. While synthetic fungicides are commonly used, there is growing interest in exploring alternative compounds that are effective against pathogens, ensure food safety, and have low toxicity to non-target organisms. In this study, we examined the biochemical changes in corn plants treated with Lippia sidoides essential oil and its major compound, thymol. Both treatments serve as preventive measures for inoculated plants and induced resistance. We tested five concentrations of each product in in vivo experiments. After evaluating the area under the disease progress curve, we analyzed leaf samples for enzymatic activities, including superoxide dismutase, catalase, ascorbate peroxidase, and chitinase. Phytoalexin induction was assessed using soybean cotyledons and sorghum mesocotyls. Cytotoxicity tests revealed lower toxicity at concentrations below 50 µL/mL. Both essential oil and thymol stimulated the production of reactive oxygen species, with thymol primarily activating catalase and L. sidoides oil increasing ascorbate peroxidase levels. Both thymol and L. sidoides were also key activators of chitinase. These findings suggest that L. sidoides essential oil and thymol are promising candidates for developing biological control products to enhance plant defense against pathogens. Full article

The taxane molecules extracted from the bark of trees from the Taxus genus demonstrate anticancer activity and are the main components of the drug paclitaxel. Even though a great deal of research has been carried out to produce them synthetically, this manufacturing is still dependent on Taxus cell culture. Furthermore, these processes are not suitable for steady taxane production. Therefore, the search for alternative sources of taxane production has generated growing interest amongst the scientific community. The use of endophytic fungi for the obtention of taxane constitutes an attractive alternative. Here, we present an analysis of the taxane production of several microorganisms through LC–QTOF MS/MS. We isolated 21 endophytic fungus strains, identified through sequencing of their internal transcribed spacer region (ITS). The phylogenetic analysis showed the presence of 11 different Fungus genera, namely Aspergillus, Trichoderma, Neurospora, Penicillium, Curvularia, Arcopilus, Biscogniauxia, Hypoxylon, Sordaria, Xylariales, and Gelasinospora. These fungi have been previously described to synthetize distinct metabolites of medical interest, hence supporting the study of their potential taxane production. Here, we report the production of taxadiene by some of these fungi, namely Aspergillus sp. (1.35 μg/L), TgO (0.7 μg/L), Trichoderma harzianum (0.13 μg/L), and Hypoxylon sp. (0.3 μg/L). Furthermore, we also detected the production of baccatin III, a crucial precursor component of the drug paclitaxel. This is the first report of taxane production by fungi phylogenetically related to the Arcopilus and Endoxyla genera. Full article

The Aloe barbadensis industry plays an important role in the economic development of Yuanjiang county of Yuxi city in Yunnan province, China. In order to reduce the harm of diseases and ensure the quality of products, the occurrence of A. barbadensis was investigated. The pathogenic fungi of wild and cultivated species of A. barbadensis were isolated by a tissue separation method, and DNA sequencing was carried out by using the sequence analysis of the ribosomal rDNA-ITS region, and the pathogenic fungi were classified and identified by finally combining morphological observations. The results showed that the main fungal diseases were root rot and leaf rot disease caused by Fusarium oxysporum, leaf spot disease caused by Curvularia lunata, anthracnose caused by Colletotrichum boninense, and brown spot disease caused by Alternaria alternata on A. barbadensis. Full article

Arid desert regions are among the harshest ecological environments on Earth. Halophytes, with their unique physiological characteristics and adaptability, have become the dominant vegetation in these areas. Currently, research on halophytes in this region is relatively limited, particularly concerning studies related to their root endophytic fungi, which have been rarely reported on. Therefore, investigating the diversity and composition of endophytic fungi in halophytes is crucial for maintaining ecological balance in such an arid environment. This study focuses on eight representative angiosperm halophytes from the West Ordos Desert in China (including Nitraria tangutorum, Salsola passerina, Suaeda glauca, Reaumuria trigyna, Reaumuria kaschgarica, Limonium aureum, Apocynum venetum, and Tripolium vulgare), utilizing Illumina MiSeq high-throughput sequencing technology combined with soil physicochemical factor data to analyze the diversity, composition, and ecological functions of their root-associated fungal communities. Ascomycota dominated the fungal composition in most halophytes, particularly among the recretohalophytes, where it accounted for an average of 88.45%, while Basidiomycota was predominant in Suaeda glauca. A Circos analysis of the top 10 most abundant genera revealed Fusarium, Dipodascus, Curvularia, Penicillium, and other dominant genera. Co-occurrence network analysis showed significant differences in fungal networks across halophyte types, with the most complex network observed in excreting halophytes, characterized by the highest number of nodes and connections, indicating tighter fungal symbiotic relationships. In contrast, fungal networks in pseudohalophytes were relatively simple, reflecting lower community cohesiveness. Redundancy analysis (RDA) and Mantel tests demonstrated that soil factors such as organic matter, available sulfur, and urease significantly influenced fungal diversity, richness, and evenness, suggesting that soil physicochemical properties play a critical role in regulating fungal–plant symbiosis. Functional predictions indicated that endophytic fungi play important roles in metabolic pathways such as nucleotide biosynthesis, carbohydrate degradation, and lipid metabolism, which may enhance plant survival in saline–alkaline and arid environments. Furthermore, the high abundance of plant pathogens and saprotrophs in some fungal communities suggests their potential roles in plant defense and organic matter decomposition. The results of this study provide a reference for advancing the development and utilization of halophyte endophytic fungal resources, with applications in desert ecosystem restoration and halophyte cultivation. Full article

Testosterone (TS) and its 1(2)-dehydrogenated derivative boldenone (BD) are widely used in medicine, veterinary science and as precursors in organic synthesis of many therapeutic steroids. Green production of these compounds is possible from androstenedione (AD) enzymatically, or from phytosterol (PS) using fermentation stages. In this study, the ascomycete Curvularia sp. VKM F-3040 was shown to convert androstadienedione (ADD, 4 and 10 g/L) to yield 97% and 78% (mol/mol) of BD, respectively. Based on its high 17β-hydroxysteroid dehydrogenase (17β-HSD) activity, a novel cascade biotransformation of PS was developed for production of TS and BD. At the first stage, the strains of Mycolicibacterium neoaurum VKM Ac-1815D or M. neoaurum VKM Ac-1816D converted PS (5 or 10 g/L) into AD or ADD (each in a concentration of 2.5 or 5 g/L), respectively. At the second stage, mycelium of the fungus under the revealed optimal conditions reduced AD or ADD with more than 90% efficiency to form TS or BD, respectively. Based on transcriptome analysis, six candidate genes that might encode 17β-HSDs in the Curvularia sp. genome were revealed. Along with 17β-HSDs, the fungus possessed inducible P450_cur 7-monooxygenase, which led to the accumulation of 7α-hydroxytestosterone (7α-OH-TS) as a major product from AD (up to 83% within 24 h after mycelium addition at the second stage of cascade biotransformation). The presence of protein synthesis inhibitor cycloheximide (CHX) prevented 7α/β-hydroxylation due to inhibition of de novo synthesis of the enzyme in the fungal cells. The results demonstrate the high biotechnological potential of the Curvularia sp. strain and open up prospects for the synthesis of valuable 17β-reduced and 7-hydroxylated steroids by cascade biotransformations. Full article

The complex structure of the plant cell wall makes it difficult to use the biomass produced by biosynthesis. For this reason, the search for new strains of microorganisms capable of efficiently degrading fiber is a topic of interest. For these reasons, the present study aimed to evaluate both the microbiological and enzymatic characteristics of the fungus Curvularia kusanoi L7strain. For this, its growth in different culture media was evaluated. Wheat straw mineralization was evaluated by gas chromatography assisted by infrared spectroscopy. The production of endo- and exoglucanase, laccase, and peroxidase enzymes in submerged solid fermentation of wheat and sugarcane bagasse were characterized. The strain efficiently mineralized raw wheat straw, showing a significant decrease in signals associated with cellulose, hemicellulose, and lignin in the infrared spectra. High enzyme productions were achieved in submerged solid fermentation of both substrates, highlighting the high production of endoglucanases in sugarcane bagasse (2.87 IU/mL) and laccases in wheat (1.64 IU/mL). It is concluded that C. kusanoi L7 is an ascomycete with a versatile enzyme production that allows it to exhaustively degrade complex fibers such as raw wheat straw and sugar cane bagasse, making it a microorganism with great potential in the bioconversion of plant biomass. Full article

Colletotrichum species are the most common cause of maize anthracnose, which often manifests as leaf spots. However, field observations often reveal symptoms similar to those caused by other leaf spot pathogens, such as Curvularia and Bipolaris. In this study, 99 isolates were identified using tissue separation and single-spore isolation techniques. As preliminary measures of species diversity, all 99 isolates were identified morphologically, and the glyceraldehyde-3-phosphate dehydrogenase (GAPDH) gene sequences were phylogenetically analyzed. Furthermore, 48 representative strains were selected for molecular identification using multi-locus phylogenetic analyses based on five gene loci (ITS, TUB, ACT, GAPDH, and CAL). Finally, 10 species of Colletotrichum isolated from maize leaf spots were identified. Colletotrichum cliviicola was the most dominant species (24.2%), followed by C. fructicola (18.2%), C. karstii (16.1%), C. siamense (13.1%), C. boninense (7.1%), C. kahawae (7.1%), C. brevisporum (6.1%), C. truncatum (5.1%), C. gigasporum (2.0%), and C. gloeosporioides (1.0%). For the first time, pathogenicity tests revealed that C. cliviicola, C. fructicola, C. siamense, C. karstii, and C. truncatum are the causative agents of maize anthracnose. Additionally, C. boninense was identified as an endophytic fungus on healthy maize. In conclusion, this study is the first to identify the pathogen of maize anthracnose in Sichuan Province. It provides valuable insights for accurately diagnosing and managing maize anthracnose. Full article