Search Results (856)

The fungal pathogen Colletotrichum jiangxiense has a broad host range and high destructive potential. It is a major causal agent of brown spot disease in diverse plants. Antifungal mechanisms used by biocontrol fungi against plant pathogens include disruption of cellular structures and cell wall damage, which can lead to protoplast leakage and hyphal lysis. In this study, we investigated the antifungal mechanism of the endophytic fungus Diaporthe novem DJ13 against C. jiangxiense, the causal agent of rhododendron brown spot. DJ13 is an effective biocontrol strain previously isolated by our research group from healthy leaves of Rhododendron pulchrum. Physiological assays showed that treatment with DJ13 fermentation broth increased membrane permeability, elevated MDA content, reduced TCA cycle enzyme activities, and increased AKP activity. These findings suggest impaired membrane integrity, disrupted energy metabolism, and cell wall damage. Transcriptomic analysis of the treated pathogen identified 1680 significantly differentially expressed genes (DEGs), including 961 up-regulated and 719 down-regulated genes. Among these genes, ABC transporter genes were significantly up-regulated, whereas genes involved in membrane structure metabolism were significantly down-regulated. Chitinase genes were up-regulated, whereas α-glucanase genes were down-regulated. DASH family cryptochrome genes were significantly down-regulated, while genes related to reactive oxygen species (ROS) production, including xanthine dehydrogenase, were significantly up-regulated. In addition, FAD-dependent oxidoreductase genes were up-regulated, while respiratory-metabolism-related genes, including trimethyllysine dioxygenase, were down-regulated. Together, the physiological and transcriptomic data provide a correlative framework supporting the hypothesis that the antifungal mechanism of DJ13 fermentation broth may involve the coordinated action of four processes: cell membrane damage, cell wall disruption, oxidative stress, and inhibition of energy metabolism. These findings also identify candidate genes for future functional validation. Full article

Rusty root rot of ginseng (Panax ginseng) caused by Ilyonectria spp. infection is a devastating soil-borne disease restricting the sustainable production of garden-cultivated ginseng (GCG) in Northeast China and causes severe yield and economic losses; GCG is far more susceptible to this pathogen than forest-cultivated ginseng (Lin-Xia-Shan-Shen, LXSS). Ginsenosides, the signature triterpenoid saponin defensive metabolites of ginseng, are characteristic dammarane-type triterpenoid defensive saponins represented by Re, Rg₂, Rb₁, Rd, and Rg₁. These compounds are continuously secreted into the rhizosphere and widely participate in plant–microbe interactions, yet their functional roles in mediating Ilyonectria infection remain poorly clarified. This study aimed to clarify how rhizospheric ginsenosides regulate the infection process of pathogenic Ilyonectria strains. Two pathogenic strains, Ilyonectria sp. SYM-1 and Ilyonectria sp. SYM-2, were found isolated from diseased GCG roots and verified as causal agents via morphological observation, molecular ITS identification and artificial inoculation infection experiments. Interestingly, the concentrations of five ginsenosides, Re, Rg₂, Rb₁, Rd, and Rg₁, in the rhizospheric soil of GCG with rusty root rot were significantly higher than those in the rhizospheric soil of healthy LXSS plants. In addition, the concentrations of ginsenosides in the LXSS rhizospheric soils decreased with increasing age of plants. Non-nutritive suspension co-culture assays showed that high concentrations of the ginsenosides Rg₁ and Rd significantly promoted spore germination of the strains SYM-1 and SYM-2. However, Rb₁ had a certain inhibitory effect on the growth of Ilyonectria sp. SYM-2. Host inoculation experiments further indicated that infection with either fungus significantly reduced the concentrations of ginsenosides produced in ginseng roots. These results demonstrate that the pathogenic fungi SYM-1 and SYM-2 of Ilyonectria can adapt to and utilize ginsenosides. Collectively, these findings prove that the two pathogenic Ilyonectria strains have evolved the capacity to adapt to and exploit rhizospheric ginsenosides to facilitate their infectivity. From an application perspective, reducing rhizospheric ginsenoside release may represent a promising theoretical strategy for ginseng cultivation and germplasm improvement, which warrants further verification by field or greenhouse experiments for validation. Full article

Pigeonpea (Cajanus cajan) shoot tip dieback was recently observed in Danzhou, Hainan Province, China, with disease incidence of 30–100% in affected fields, but its causal agent and management options remained unclear. This study aimed to isolate and identify the fungal agent associated with the disease, verify its pathogenicity, characterize its biological traits and effects on host growth, and screen candidate fungicides. Fungal isolates were obtained from symptomatic shoot margins and purified by hyphal-tip and single-spore isolation. Representative isolates LYZ0717, LYZ0718, and LYZ0719 were characterized by colony morphology, pycnidial and conidial traits, and combined phylogenetic analysis of ITS and TEF1-α sequences. These analyses identified the isolates as Lasiodiplodia theobromae. Spray inoculation of 20-day-old pigeonpea seedlings reproduced typical shoot tip dieback symptoms within 6 days, and the inoculated fungus was reisolated from symptomatic tissues, fulfilling Koch’s postulates. The pathogen grew over a pH range of 3–11 and at temperatures of 5–35 °C, with optimal mycelial growth at 25–30 °C and maximum sporulation under acidic conditions. At 20 days after inoculation, infection reduced plant height, dry weight, and total flavonoid content by 45.21%, 75.88%, and 42.19%, respectively. Among the seven fungicides tested, trifloxystrobin–tebuconazole and thiophanate-methyl showed the strongest in vitro inhibition, with EC₅₀ values of 0.0270 and 0.0614 ppm, respectively. In greenhouse pot experiments, thiophanate-methyl achieved the highest disease control efficacy, reaching 64.35% after the second application. These findings demonstrate that L. theobromae is the causal agent of pigeonpea shoot tip dieback in China and provide a basis for disease diagnosis, biological understanding, and fungicide-based management. Full article

Sclerotinia sclerotiorum is a formidable soilborne fungus that wreaks havoc on numerous crops globally. While the role of ADP-ribosylation factor-like 1 (Arl1) small GTPases in vesicular trafficking and fungal development is well-documented, their specific impact on S. sclerotiorum remains unclear. Through reverse genetic techniques, we identified and characterized SsArl1, a typical Arl small GTPase conserved across fungi. Deleting SsArl1 hampers the hyphal growth of S. sclerotiorum, but leads to higher oxalic acid buildup and boosts cellulase activity. This speeds up the infection of host plants, yet increases their sensitivity to certain environmental stresses, particularly ionic and cell wall-related stress. Our results reveal that SsArl1 acts as a negative regulator of oxalic acid accumulation and virulence, while playing a positive role in enhancing resistance to environmental stresses in S. sclerotiorum. Full article

Chinese Cordyceps (Ophiocordyceps sinensis) and Xinjiang Cordyceps (Paraisaria gracilis) are related entomopathogenic fungi that occupy different elevations and habitats. Whether their holobiont architectures have diverged accordingly is unknown. In this hypothesis-generating study based on samples from single locations (Altai Mountains for Xinjiang Cordyceps and Nagqu, Tibet for Chinese Cordyceps), we compared the two species using amplicon sequencing, untargeted metabolomics, and comparative genomics. Chinese Cordyceps from the sampled site comprises a specialized parasitic fungus and host-adapted bacteria for nutrient acquisition. Xinjiang Cordyceps from the Altai site contains diverse saprotrophic fungi and a rhizosphere-like bacterial consortium enriched in oxidative defense and biofilm genes, a finding that may explain why its sclerotia remain intact for 3–5 years in this population. Metabolomic profiles distinguish the two species at these sites. Xinjiang Cordyceps shows upregulation of tyrosine and porphyrin pathways, and its bacterial community shows functional enrichment in the same pathways, suggesting cross-kingdom coordination. P. gracilis has lost many gene families, and the retained species-specific genes are linked to cell adhesion and acyltransferase activity. Xinjiang Cordyceps is not a simple substitute for Chinese Cordyceps but appears to represent a different ecological strategy shaped by genome streamlining and host–microbe coadaptation. Our findings generate testable hypotheses for future large-scale, multi-population investigations. Full article

Following the elucidation of the fungal bioluminescence pathway (FBP), it was quickly adopted as a reporter system in plants; however, no such application has been documented in fungi to date. In this study, we established for the first time a luminescent reporter in the commercially important mushroom Hypsizygus marmoreus by expressing the luciferase gene from the luminous fungus Neonothopanus nambi. Using an established Agrobacterium-mediated transformation method, we separately introduced the wild-type luciferase gene nnLuz and the previously reported optimized variant nnLuz-v4 that can enhance bioluminescence expression into H. marmoreus arthroconidia. Both genes were stably integrated into the genome and expressed under the control of the H. marmoreus Glycerol 3-phosphate dehydrogenase (GPD) gene promoter. Upon addition of exogenous luciferin, transformants carrying the wild-type nnLuz produced clear, readily detectable bioluminescence signals, whereas no luminescence was observed in untransformed controls. Unexpectedly, the wild-type luciferase consistently exhibited substantially higher luminescence intensity than the optimized nnLuz-v4 variant. This finding suggests that codon optimization may be unnecessary or even detrimental when the donor and host are phylogenetically close basidiomycetes. The successful deployment of the fungal luciferase gene in H. marmoreus provides a sensitive and non-invasive genetic tool that does not require external excitation. This system opens new avenues for promoter characterization, real-time gene expression monitoring during mushroom development, and molecular breeding efforts aimed at improving agronomically important traits. Full article

Cordyceps militaris is a well-known edible and medicinal entomopathogenic fungus that can be cultivated using silkworm larvae as hosts. However, no reports have been found regarding the gut microbiota of silkworms (Bombyx mori) following C. militaris injection. Based on three biological replicates, illumina 16S rRNA gene sequencing was used to investigate the changes over time in the gut bacteria and fungi of silkworms injected with C. militaris. The results indicated that following inoculation with C. militaris, the abundance of Bacillales and Basidiomycetes increased, while that of Pseudomonadales and Ascomycetes decreased. The abundance of Mammaliicoccus increased by 78% and 26% in dying silkworms compared to their pre-inoculated counterparts and blank control group, respectively. The relative abundance of Rhodotorula in dying silkworms was 2.89-fold and 80.51-fold higher than that in the pre-inoculation group and blank control group, respectively. After inoculation with C. militaris, fungi showed the greatest community variations at day 2, while bacteria displayed the most distinct differences at day 4. Under C. militaris infection, the abundance of all four pathways of Genetic Information Processing in silkworm larvae’s gut microbiota significantly increased. Taken together, the results demonstrate that inoculation with C. militaris induced significant alterations in the composition, structure, assembly, and predictive functional profiles of gut bacteria and fungi in silkworms. This study provides a theoretical basis for exploring the production of C. militaris using silkworm larvae as insect hosts. Full article

Aspergillus nidulans, a model filamentous fungus endowed with well-established genetic tools and a repertoire of cryptic secondary metabolite biosynthetic gene clusters (BGCs), is extensively exploited as a microbial chassis for heterologous biosynthesis. Mining of its secondary metabolites facilitates the discovery of novel bioactive compounds and the development and application of chassis cells. In the course of heterologous expression of exogenous genes in A. nidulans, we unexpectedly observed the activation of cryptic host BGCs, which resulted in substantial alterations to its secondary metabolic profile. Four previously undescribed compounds (1–4), together with six known analogs (5–10), were isolated from three recombinant A. nidulans strains. Notably, compounds 1–3 are the first naturally occurring examples of diketopiperazine–isoindolinone hybrid alkaloids, while compound 4 is a previously unreported benzofuran carboxylic acid derivative. Their structures and absolute configurations were assigned by interpretation of a combination of spectroscopic data and electronic circular dichroism calculations. Compounds 4 and 5 exhibited potent DPPH radical scavenging activity (IC₅₀, 6.01 and 7.00 μg·mL⁻¹, respectively). This study uncovers a “metabolic perturbation” effect on the host metabolic network during heterologous expression and offers a new strategy for activating silent gene clusters and discovering novel natural products through genetic manipulation. Full article

Bombyx batryticatus is a traditional Chinese medicinal material derived from Bombyx mori infected by Beauveria bassiana; however, its formation mechanism remains poorly understood. This study compared infection processes in silkworms by two B. bassiana strains with markedly different virulence (highly virulent ZY027 and ARSEF2860). Integrated transcriptomic and proteomic analyses were employed to uncover, for the first time, the molecular basis of B. batryticatus formation at the systems biology level. The results demonstrated significant weight variations in B. batryticatus derived from different fungal strains. ZY027-induced stiff silkworms exhibited higher wet and dry weights than those infected by ARSEF2860. Large-scale gene reprogramming occurred in silkworm hemolymph post-infection, involving marked activation of Toll/Imd immune signaling pathways, ribosome biogenesis, and endoplasmic reticulum stress responses. A notable “uncoupling” between transcriptomic and proteomic profiles was identified, highlighting the critical role of post-translational regulation in host responses. The two strains triggered distinct metabolic reprogramming patterns: ZY027 notably suppressed oxidative phosphorylation and activated detoxification mechanisms, whereas ARSEF2860 presented characteristics of “immune–metabolic optimization.” These findings suggest that B. batryticatus formation involves complex fungus–silkworm molecular interactions in hemolymph, and that fungal strain characteristics are associated with significant differences in host molecular responses and product biomass. The study provides a theoretical foundation and innovative guidance for selecting strains with high B. batryticatus production potential and developing novel entomopathogenic fungal resources. Full article

Rice (Oryza sativa L.) production is severely threatened by rice blast disease caused by the hemibiotrophic fungus Magnaporthe oryzae. Chemical fungicides, although effective, cause environmental pollution, disrupt soil microbiomes, and select for resistant pathogen populations, creating an urgent need for sustainable alternatives. In this study, we isolated Kitasatospora hibisci strain 21007 from mangrove soil and evaluated its biocontrol potential through integrated phenotypic and transcriptomic analyses. The cell-free culture filtrate (CFCF) extract showed potent antifungal activity, inhibiting M. oryzae mycelial growth and suppressing conidial germination as well as appressorium formation in a concentration-dependent manner via antibiosis. Fermentation optimization identified Gauze’s Synthetic Medium No. 1 as optimal for metabolite production. Both inoculation of M. oryzae spores with 21007 CFCF extract and pre-treatment of rice seedlings with 21007 CFCF significantly reduced disease severity under greenhouse conditions. Transcriptomic analysis revealed extensive reprogramming of gene expression in leaves of rice seedlings cultured with 21007 CFCF extract. KEGG pathway enrichment analysis indicated activation of the plant–pathogen interaction and MAPK signaling pathways in rice seedlings cultured with 5% and 10% CFCF extract, suggesting that 21007 CFCF induces host defense signaling. These results support the potential of K. hibisci 21007 as a candidate for sustainable biocontrol of rice blast disease and establish a foundation for future metabolomic and genomic investigations. Full article

Bark beetle–fungus associations are essential for nutrition, detoxification, and host colonisation, but their composition and function vary across developmental stages and environmental contexts. Hence, we characterised the fungal communities associated with two pine-feeding bark beetles, Ips sexdentatus (ISX) and Ips acuminatus (IAC), across developmental stages and compared wild-collected and laboratory-bred populations using ITS2 amplicon sequencing. Both beetle species maintained a stable core mycobiome dominated by Kuraishia, Ogataea, Ophiostoma, Graphilbum, and Cyberlindnera. These taxa have been earlier reported to be associated with nutrient provisioning, detoxification of host secondary metabolites, and chemical signalling. Adult beetles showed species-specific community differences, whereas wild-collected beetles, particularly IAC, harboured higher fungal diversity than laboratory populations, indicating a strong environmental effect. Beetles shared more fungal taxa with control wood than with gallery wood, suggesting possible fungal acquisition during feeding and concurrent restructuring of the wood mycobiome during infestation. Monoterpene bioassays with selected yeast symbionts showed differential growth responses to α-pinene, 3-carene, and terpinolene, and their mixture, with the mixture producing stronger inhibition than individual compounds. These yeast symbionts further displayed selective antagonistic activity in vitro against selected filamentous fungi, including entomopathogenic taxa, along with detectable lytic and digestive enzyme activities. Together, our findings highlight a link between community structure, predicted functions, and observed interaction phenotypes, providing a strong basis for future mechanistic studies of beetle–fungus–conifer interactions. Full article

Cotton Verticillium wilt (VW), caused by the soil-borne fungus Verticillium dahliae (V. dahliae), is a devastating disease that poses a serious threat to sustainable cotton production worldwide. Protein methylation plays a critical role in fungal adaptation to the host environment and manipulation of plant immunity. Protein arginine methyltransferases (PRMTs) are key enzymes catalyzing arginine methylation, yet their functions in V. dahliae pathogenicity remain largely unexplored. In this study, we identified VdPRMT4 in V. dahliae through homology-based screening. qRT-PCR analysis revealed that VdPRMT4 transcript levels were significantly increased during the early stages of V. dahliae infection in cotton. HIGS assays showed that silencing VdPRMT4 markedly alleviated cotton VW symptoms and reduced fungal biomass in cotton plants. Gene knockout and complementation experiments demonstrated that deletion of VdPRMT4 did not affect hyphal growth but significantly impaired sporulation capacity and severely attenuated pathogenicity on cotton. Transcriptomic analysis further indicated that loss of VdPRMT4 profoundly affected the metabolic pathways of V. dahliae, including protein processing in the endoplasmic reticulum, purine metabolism, and glycerolipid metabolism. Collectively, this study provides the first evidence that VdPRMT4 plays a critical role in stress adaptation and pathogenicity of V. dahliae, offering new insights into fungal pathogenesis and identifying potential targets for VW control. Full article

Induced resistance primes host immunity for enhanced protection; however, how pathogens respond to this primed state remains poorly understood. Here, we investigated the molecular responses of the rice blast fungus Magnaporthe oryzae during infection of benzothiadiazole (BTH)-primed rice. Seed priming with BTH conferred long-lasting resistance against M. oryzae at the four-leaf stage. Time-course transcriptomic analyses (12–48 hpi) identified 699 differentially expressed genes (DEGs) in M. oryzae, revealing a distinct temporal transition during infection of BTH-primed rice. The fungal transcriptional response shifted from early growth and environmental sensing to enhanced protein turnover, metabolic repression, energy depletion, and genomic instability, indicating progressive impairment of fungal fitness by host immunity. From these DEGs, eight BTH-suppressed candidate virulence genes (MoBVG1–8) were selected for functional characterization. Gene overexpression analyses showed that two genes, MoBVG2 and MoBVG6, significantly increased pathogenicity on BTH-primed rice, while knockout analyses confirmed that both are required for full pathogenicity on non-primed control plants. MoBVG2 encodes a reactive oxygen species (ROS)-scavenging effector, and MoBVG6 encodes an environmental sensor, highlighting the importance of ROS detoxification and environmental perception for successful host colonization. Functional analyses further revealed that MoBVG2 contribute to vegetative growth, while MoBVG6 is required for proper appressorium development. Together, these findings suggest that BTH-induced resistance restricts blast disease by impairing fungal metabolic fitness and suppressing key virulence genes, providing novel insights into the pathogen-side molecular mechanisms underlying chemically induced resistance in plants. Full article

An isolate of Peniophora lycii was obtained from grapevine, and its interactions with several grapevine-associated fungi and the plant host were examined. The fungus was not able to infect intact leaves, but necrotized the margins of foliar disks and caused necrosis and white rot in woody tissues. In dual cultures, P. lycii and Aureobasidium pullulans showed mutual antagonism. Mycoparsitism of P. lycii was observed on epiphytic Botrytis cinerea, Alternaria sp., and endophytic Botryosphaeria dothidea interaction partners. In contrast, P. lycii showed trophic growth towards endophytic Phaeomoniella chlamydospora without any signs of harmful interactions. Dual inoculations of foliar disks with epiphytic fungi revealed no effects of fungal interactions on necrosis development by pathogens and verified mycoparasitic interactions in planta. Co-infection assays of cuttings with endophytic pathogen fungi showed cumulative effects of fungal interactions on wood symptom expression, with the exclusive contribution of P. lycii to white rot development. In addition to providing the first isolation of P. lycii from grapevine and the description of its mycoparasitic behavior, the present study suggests that the fungus may act as an opportunistic grapevine pathogen, probably as a secondary colonizer in trunk diseases. The observed dual host preference may allow trunk disease pathogens to initially feed on fungi, followed by damage to the grapevine. This may be in connection with the exceptionally long latency of these syndromes. Full article

The appressorium is a specialized infection structure formed by Metarhizium anisopliae during host invasion. To investigate the correlation between appressorium formation and fungal pathogenicity, as well as its impact on insect cuticular metabolism, different concentrations of sulforaphane were used to inhibit the appressorium formation rate of M. anisopliae. The relationship between appressorium formation rate and pathogenicity against Opisina arenosella larvae was evaluated, and LC-MS-based metabolomics was employed to characterize changes in cuticular compounds during the appressorium formation stage, thereby elucidating the chemical responses of the insect cuticle to appressorium formation. The appressorium formation rate of M. anisopliae was significantly and positively correlated with its pathogenicity (p ≤ 0.05). As the appressorium formation rate increased, pathogenicity against O. arenosella larvae increased and the killing speed accelerated. LC-MS metabolomics revealed that after appressorium formation, 102 differential cuticular compounds unique to O. arenosella larvae were identified, mainly including benzenes and substituted derivatives, amino acids and derivatives, and heterocyclic compounds. In addition, metabolic pathways associated with immune defense (tyrosine metabolism), antifungal defense (histidine metabolism), and toxin degradation (flavonoid degradation) in the larval cuticle were activated. These results demonstrate that the appressorium plays an important role in host infection by M. anisopliae, markedly alters cuticular metabolism, and activates defense- and detoxification-related metabolic pathways in the host. This study provides a theoretical basis for further investigations into fungus–insect cuticle interactions. Full article