Search Results (47)

Clonostachys rosea, an entomopathogenic fungus that infects Cephalcia chuxiongica, is highly pathogenic and has significant potential for controlling the damage this pest causes to pine forests. To investigate the role of C. rosea secondary metabolites in fungal pathogenicity, we conducted toxicity assays using crude metabolite extracts. These assays evaluated the effects of different concentrations, larval developmental stages, and exposure methods on larval mortality. Gas chromatography–mass spectrometry (GC–MS) was subsequently employed to identify the chemical constituents of the crude extracts, and the toxicity of the identified compounds was assessed. The results showed that the crude extract at a concentration of 7.5 μg/mL exhibited the highest toxicity. Two hours post-treatment, the mortality rate of non-diapause larvae reached 65%, which was significantly higher than that of the diapause group. Moreover, contact toxicity was more lethal to C. chuxiongica larvae than oral exposure. A total of 23 compounds were identified from the crude extract, of which nine exhibited toxicity: 2-piperidone, hydrocinnamic acid, phenethyl alcohol, oleic acid, tryptophol, stearic acid methyl ester, myristic acid, dodecanoic acid, and benzeneacetic acid. Except for 2-piperidone, which showed low toxicity, the other eight compounds demonstrated notable contact toxicity against C. chuxiongica larvae. These findings confirm the insecticidal potential of C. rosea secondary metabolites and provide a valuable reference for the biological control of C. chuxiongica and other chewing insect pests. Full article

The undefined microbial ecology of Aconitum carmichaelii root rot in western Yunnan constrains the advancement of eco-friendly control strategies. The identification of potential pathogenic determinants affecting A. carmichaelii growth is imperative for sustainable cultivation and ecosystem integrity. High-throughput sequencing was employed to profile microbial communities across four critical niches, namely rhizosphere soil, tuberous root epidermis, root endosphere, and fibrous roots of healthy and diseased A. carmichaelii. The physicochemical properties of corresponding rhizosphere soils were concurrently analyzed. Putative pathogens were isolated from diseased rhizospheres and tubers through culturing with Koch’s postulates validation, while beneficial microorganisms exhibiting antagonism against pathogens and plant growth-promoting (PGP) traits were isolated from healthy rhizospheres. Highly virulent strains (2F14, FZ1, L23) and their consortia were targeted for suppression. Strain DX3, demonstrating optimal PGP and antagonistic capacity in vitro, was selected for pot trials evaluating growth enhancement and disease control efficacy. Significant disparities in rhizosphere soil properties and bacterial/fungal community structures were evident between healthy and diseased cohorts. Fifteen putative pathogens spanning eight species across four genera were isolated: Fusarium solani, F. avenaceum, Clonostachys rosea, Mucor racemosus, M. irregularis, M. hiemalis, Serratia liquefaciens, and S. marcescens. Concurrently, eight PGP biocontrol strains were identified: Bacillus amyloliquefaciens, B. velezensis, B. subtilis, B. pumilus, and Paenibacillus polymyxa. Pot trials revealed that Bacillus spp. enhanced soil physiochemical properties through nitrogen fixation, phosphate solubilization, potassium mobilization, siderophore production, and cellulose degradation, significantly promoting plant growth. Critically, DX3 inoculation elevated defense-related enzyme activities in A. carmichaelii, enhanced host resistance to root rot, and achieved >50% disease suppression efficacy. This work delineates key pathogenic determinants of Yunnan A. carmichaelii root rot and identifies promising multifunctional microbial resources with dual PGP and biocontrol attributes. Our findings provide novel insights into rhizosphere microbiome-mediated plant health and establish a paradigm for sustainable disease management. Full article

Cephus fumipennis, a significant pest of highland spring wheat, damages crops through larval boring and feeding within wheat stalks. This activity disrupts nutrient and water transport, causing severe yield reductions. To find microbial biocontrol agents targeting this pest, primary entomopathogenic microorganisms were isolated and identified from naturally infected, deceased C. fumipennis larvae. Morphological examination and ITS-based phylogenetic analysis tentatively identified the isolate as the entomopathogenic fungus Clonostachys sp. (strain CF01). Third-instar larvae of C. fumipennis were inoculated with conidial suspensions of the CF01 strain at concentrations of 1 × 10⁵, 1 × 10⁶, 1 × 10⁷, and 1 × 10⁸ spores/mL. Spore suspensions of different concentrations demonstrated pathogenicity against third-instar larvae of C. fumipennis. The optimal growth conditions for strain CF01 were identified as follows: PPDA medium, 25 °C, fructose as the carbon source, and yeast extract as the nitrogen source. Photoperiod exhibited no significant effect on either mycelial growth or sporulation. These findings indicate that the CF01 strain possesses considerable potential for the biocontrol of C. fumipennis. Full article

Pelleting seeds to enhance sowing conditions through the incorporation of pesticides or fertilizers has become a prevalent agricultural practice. This study sought to evaluate the effect of pelletized seeds and the substances they release in the form of an extract on four species of nematophagous fungi. The fungus Pleurotus ostreatus was the most sensitive to the presence of pelletized seeds; the growth of all three evaluated strains of P. ostreatus was inhibited from 42.84 to 94.33% compared to the control. In the case of the fungi Stropharia rugosoannulata and Orbilia oligospora, a statistically significant inhibition of the growth of all three evaluated strains was observed, though this inhibition was less pronounced than in the case of P. ostreatus. In contrast, the inhibitory effect on the fungus Clonostachys rosea exhibited a lower inhibition of mycelial growth (0.65–20.41%) compared to the control. The selection of suitable strains of nematophagous fungi tolerant to substances used for seed pelletization could assist in the management of nematodes. The inoculum of nematophagous fungi can be used in sugar beet sowing as a supplement, but fungi should not be used as part of the seed coatings because their viability is most inhibited in direct contact with fungicides. Full article

Viticulture is vital to Italy’s agricultural sector, since it significantly contributes to the global wine industry. Microflora and microfauna are considered important factors for soil quality, improving grapevine growth, and promoting resistance to biotic and abiotic stresses. This study examined the impact of selected Trichoderma strains (T. harzianum M10 and T. afroharzianum T22) and their secondary metabolite 6-pentyl-α-pyrone (6PP) on the soil microbiome, the metabolome, and physiological changes of grapevines. Before treatment application, low levels of plant-parasitic nematodes (Rotylenchulus spp., Xiphinema pachtaicum) were found in the soil, together with pathogens (Fusarium spp., Neonectria spp.) and beneficial microbes (Clonostachys rosea, Pseudomonas spp.). Metagenomic analysis revealed significant treatment impacts in the soil microbiome, with T22 and 6PP treatments increasing Proteobacteria abundance, while slight variations of fungal communities and no significant differences in nematofauna were found. Metabolomic analysis showed that treatments induced grapevines to produce antioxidant secondary metabolites able to boost plant defense against abiotic and biotic stresses and increase nutraceutical grapes’ value. Finally, T22 treatment increased the grapes’ winemaking value, raising their Brix grade. Our results demonstrate that microbial or metabolite-based treatments could affect the soil microbiome composition, grapevine health and resilience, and grapes’ oenological and nutraceutical properties. Full article

Transcription factors are extensively found in fungi and are involved in the regulation of multiple biological processes, including growth, development, conidiation, morphology, stresses tolerance, and virulence, as well as the production of secondary metabolites. Biocontrol is a complex biological process through which several biocontrol behaviors, such as the secretion of cell wall-degrading enzymes and the production of secondary metabolites, are regulated by transcription factors. To date, biocontrol-related transcription factors have been reported in several biocontrol fungi, such as Beauveria bassiana, Clonostachys rosea, Coniothyrium minitans, and different species in the genera Metarhizium, Trichoderma, and Arthrobotrys. However, comprehensive reviews summarizing and analyzing transcription factors with biocontrol potential in these fungi are scarce. This review begins by giving a basic overview of transcription factors and their functions. Then, the role of biocontrol-related transcription factors in biocontrol fungi is discussed. Lastly, possible approaches for further work on transcription factors in biocontrol fungi are suggested. This review provides a basis for further elaborating the molecular mechanisms of transcription factors in the context of biocontrol. Full article

An acidic shift in the pH profile of Clonostachys rosea zearalenone hydrolase (ZHD), the most effective and well-studied zearalenone-specific lactone hydrolase, is required to extend the range of applications for the enzyme as a decontamination agent in the feed and food production industries. Amino acid substitutions were engineered in the active center of the enzyme to decrease the pKa values of the catalytic residues E126 and H242. The T216K substitution provided a shift in the pH optimum by one unit to the acidic region, accompanied by a notable expansion in the pH profile under acidic conditions. The engineered enzyme demonstrated enhanced activity within the pH range of 3–5 and improved the activity within the pH ranging from 6 to 10. The D31N and D31A substitutions also resulted in a two-unit shift in the pH optimum towards acidic conditions, although this was accompanied by a significant reduction in the enzyme activity. The D31S substitution resulted in a shift in the pH profile towards the alkaline region. The alterations in the enzyme properties observed following the T216K substitution were consistent with the conditions required for the ZHD application as decontamination enzymes at acidic pH values (from 3.0 to 6.0). Full article

The Dubas bug is a serious and widespread pest of date palms in several countries in the Middle East. Chemical pesticides are widely used for managing this pest; however, most pesticides fail due to the continuous development of pesticide resistance. The primary goal of this research was to isolate endophytic fungi and test their entomopathogenic activity against Dubas bug nymphs and adults. A total of 27 fungal isolates were obtained and identified using the nuc rDNA internal transcribed spacer (ITS1-5.8S-ITS2 = ITS) region. These strains represent 16 species, belonging to 10 genera of seven different families, Ascomycota with six families and Basidiomycota with a single family, Quambalariaceae. Due to its remarkable biological control ability against insect pests, Clonostachys rosea was further studied for its entomopathogenic activity against Ommatissus lybicus nymphs and adults in comparison to a commercial strain of Beauveria bassiana. The concentration of 1 × 10⁸ conidia/mL of the selected endophytic isolate was used in lab experiments targeting Dubas bug healthy nymphs and adults. After 7 days of C. rosea treatment, the isolate caused significant mortality rates of 85% in the adult insects, while the mortality rates were moderate in the nymphs (33%). The commercial strain of B. bassiana resulted in 100% mortality levels in nymphs and adults of the Dubas bug. Scanning electron microscopy (SEM) of O. lybicus adults treated with C. rosea and B. bassiana showed mycelium growing on the eye, antenna, cuticle, and egg oviposition parts of O. lybicus. Mycelium growth of both fungi was also evident on the nymphs. This study reports for the first time the isolation of C. rosea from the Dubas bug, and its high entomopathogenic activity against an adult population of O. lybicus. Full article

Gastrodia elata, commonly known as Tian Ma, is a perennial mycoheterotrophic orchid. Qianyang Tian Ma (QTM), a geographical indication agricultural product from Hongjiang City, Hunan Province, China, is primarily characterized by the red variety, G. elata f. elata. A severe outbreak of tuber brown rot disease was documented in QTM during the harvesting season in Hunan. The fungal pathogen associated with the disease was isolated on potato saccharose agar (PSA) and identified through morphological and phylogenetic analyses. Pathogenicity tests were performed on healthy tubers of G. elata f. elata. The results showed that the representative isolate, named TMB, produced white hyphal colonies with a ring structure, broom-like phialides, partially curved ellipsoidal conidia, and orange–yellow spherical ascocarps on PSA. Phylogenetic analysis of the ITS, LSU, rpb2 and tub2 sequences using Bayesian and maximum-likelihood methods identified the isolate TMB as Clonostachys rosea, based on morphological and phylogenetic data. Pathogenicity tests revealed typical disease symptoms on healthy G. elata tubers 15 days post-inoculation with the isolate TMB. C. rosea is known to cause diseases in economically important crops, but there are no reports of its occurrence on G. elata f. elata in China. This study provides valuable insights into the occurrence, prevention, and control of brown rot disease in G. elata f. elata. Full article

Radiata pine is one of the most commonly planted tree species in Chile due to its fast growth and desirable wood and pulp properties. However, its productivity is hampered by several diseases. Pitch canker disease (PCC) caused by Fusarium circinatum, is considered the most damaging disease to the pine forest industry. Several control measures have been established, with biological control emerging as an environmentally friendly and effective way for F. circinatum control. Previous studies support the value of Clonostachys rosea in reducing PCC damage, with evidence suggesting a potential induced systemic resistance (ISR) triggered in radiata pines by this agent. Ten-month-old radiata pine plants were pre-treated with C. rosea on a substrate at 8 and 1 days before inoculation with F. circinatum on the stem tip, and expression levels were determined for DXS1, LOX, PAL, and PR3 genes 24 h later. Lesion length was 45% lower on plants pre-treated with C. rosea and infected with F. circinatum compared to non-pre-treated and infected plants. Additionally, LOX and PR3 were induced 23 and 62 times more, respectively, in comparison to untreated plants. Our results indicate that C. rosea causes an ISR response in pre-treated plants, significantly increasing the expression of resistance genes and reducing lesion length. Full article

Narrow-leaved ash (Fraxinus angustifolia Vahl), a highly valued European forest tree species, has been severely affected by a large-scale decline, which is most probably driven by a complex of multiple interacting factors including fungi, which contribute to and accelerate this process. Red deer (Cervus elaphus L.) can be considered as one of the contributing factors, as they inflict damage on the stems of young trees by stripping the bark. These wounds not only represent suitable entry points for fungi which can cause tissue necroses and decomposition, they can lead to changes in the wood structure as well. The aims of this research were to analyze chosen parameters of bark stripping wounds in narrow-leaved ash stands, identify fungi present in the tissue exposed by wounding, and inspect the effect of wounding on the wood structure. Bark stripping was observed on ash trees from 2 cm up to 18 cm of DBH and between 0.1 m and 1.9 m of stem height. The most susceptible trees were those with an average DBH of 5 ± 2.5 cm. On most of the ash trees (51%), one-third to two-thirds of the circumference was damaged. In wounded tissue, 174 fungal isolates were found, most of which belonged to known endophytic fungi from the genera Trichoderma, Fusarium, and Clonostachys. It was observed that earlywood cells in the wounding zone had narrower lumens compared to ones in adjacent healthy zone with regard to different trees and stem heights. Full article

Given their numerous positive characteristics, composts are widely used agriculturally in sustainable development and resource-saving technologies. The management of phytopathogen-suppressive potential and the fertilizing capacity of composts are of great interest. This study examines the impact of introducing the autochthonous compost species Bacillus subtilis, B. amyloliquefaciens, Pseudomonas aeruginosa, and Aspergillus corrugatus, both individually and in combination, to composts containing dry matter comprising 36% solid compost and 7% compost suspensions to study their phytopathogen-suppressive and phytostimulation activity. The test phytopathogens were Clonostachys rosea, Penicillium solitum, and Alternaria alternata. This is the first report on compost’s potential to biologically control C. rosea and P. solitum. Classical microbiological and molecular biological methods were used to evaluate the survival rate of microorganisms in compost and validate these results. Test plant (Raphanus sativus) germination indexes were determined to evaluate the phytotoxic/phytostimulation effects of the substrates. To assess the effectiveness of biocontrol, mycelial growth inhibition was measured using in vitro tests. The introduction of composition increased the composts’ fertilizing properties by up to 35% and improved antagonistic activity by up to 91.7%. Autochthonous bacterial–fungal composition can promote resistance to fungal root and foliar phytopathogens and raise the fertilizing quality of compost. Full article

This study aimed to evaluate the suppressive potential of different soils on soybean cyst nematodes (SCN) and to estimate the suppressive mechanism. Fifteen soils (designated as soil A to O) from different agricultural fields with varying organic inputs were added with SCN-infested soil and grown with a green soybean variety. The SCN density in the soil at 6 weeks of soybean growth was markedly different depending on the soils used, indicating a different level of disease suppressiveness. No significant correlation was observed between the SCN density and any of the soil physicochemical and biological characteristics tested. Then, to estimate a suppression mechanism, F-soil that showed the lowest density of SCN was added to the SCN-infested soil with or without streptomycin to kill bacteria and grown with soybean. SCN density was not increased by the addition of streptomycin, indicating that soil bacteria may not be involved in the suppressiveness of F-soil. In total, 128 fungal strains were isolated from the rhizosphere of F-soil and inoculated in a combination or singly in the SCN-infested soil. After repeated screenings, five strains were selected since the SCN density was consistently decreased by them. Sequence analysis showed that they were closest to Clonostachys rosea, Aspergillus niger, Aspergillus fumigatus, Fusarium oxysporum, and Cylindrodendrum alicantinum. All five strains significantly reduced the mobility of second-stage juveniles (J2). Further, C. rosea a2, A. niger a8, and F. oxysporum a25 significantly decreased hatching. Overall, the present study demonstrated that soil fungi played an important role in SCN suppression in F-soil. Full article

Fusarium spp. are important pathogens on cereals, capable of causing considerable yield losses and significantly reducing the quality of harvested grains due to contamination with mycotoxins. The European Union intends to reduce the use of chemical-synthetic plant protection products (csPPP) by up to 50% by the year 2030. To realize this endeavor without significant economic losses for farmers, it is crucial to have both precise early detection of pathogens and effective alternatives for csPPP. To investigate both the early detection of Fusarium head blight (FHB) and the efficacy of selected biological control agents (BCAs), a pot experiment with spring wheat (cv. ‘Servus’) was conducted under semi-field conditions. Spikes were sprayed with different BCAs prior to inoculation with a mixture of F. graminearum and F. culmorum conidia. While early detection of FHB was investigated by hyperspectral imaging (HSI), the efficiency of the fungal (Trichoderma sp. T10, T. harzianum T16, T. asperellum T23 and Clonostachys rosea CRP1104) and bacterial (Bacillus subtilis HG77 and Pseudomonas fluorescens G308) BCAs was assessed by visual monitoring. Evaluation of the hyperspectral images using linear discriminant analysis (LDA) resulted in a pathogen detection nine days post inoculation (dpi) with the pathogen, and thus four days before the first symptoms could be visually detected. Furthermore, support vector machines (SVM) and a combination of LDA and distance classifier (DC) were also able to detect FHB symptoms earlier than manual rating. Scoring the spikes at 13 and 17 dpi with the pathogen showed no significant differences in the FHB incidence among the treatments. Nevertheless, there is a trend suggesting that all BCAs exhibit a diminishing effect against FHB, with fungal isolates demonstrating greater efficacy compared to bacterial ones. Full article

Clonostachys rosea is an excellent biocontrol fungus against numerous fungal plant pathogens. The cAMP signaling pathway is a crucial signal transduction pathway in fungi. To date, the role of the cAMP signaling pathway in C. rosea mycoparasitism remains unknown. An adenylate cyclase-encoding gene, crac (an important component of the cAMP signaling pathway), was previously screened from C. rosea 67-1, and its expression level was dramatically upregulated during the C. rosea mycoparasitization of the sclerotia of Sclerotinia sclerotiorum. In this study, the function of crac in C. rosea mycoparasitism was explored through gene knockout and complementation. The obtained results show that the deletion of crac influenced the growth rate and colony morphology of C. rosea, as well as the tolerance to NaCl and H₂O₂ stress. The mycoparasitic effects on the sclerotia of S. sclerotiorum and the biocontrol capacity on soybean Sclerotinia stem rot in ∆crac-6 and ∆crac-13 were both attenuated compared with that of the wild-type strain and complementation transformants. To understand the regulatory mechanism of crac during C. rosea mycoparasitism, transcriptomic analysis was conducted between the wild-type strain and knockout mutant. A number of biocontrol-related genes, including genes encoding cell wall-degrading enzymes and transporters, were significantly differentially expressed during C. rosea mycoparasitism, suggesting that crac may be involved in C. rosea mycoparasitism by regulating the expression of these DEGs. These findings provide insight for further exploring the molecular mechanism of C. rosea mycoparasitism. Full article