Search Results (92)

Avicennia germinans, a representative of the marine coastal mangrove ecosystem, vital in the Colombian Caribbean, harbors a unique microbial diversity that could contain microorganisms with the potential to promote plant growth of agricultural species such as maize. The objective of this research was to evaluate A. germinans endophytes at different sampling sites and in diverse plant organs in order to identify the growth-promoting role of the most sodium chloride-tolerant endophyte found. These were then inoculated in maize seeds under drought stress conditions simulated by polyethylene glycol (PEG) in vitro. To this end, samples of adult A. germinans plants were collected from four mangrove ecosystems in the Colombian Caribbean. Several isolates were able to tolerate up to 15% NaCl (w/v), produce indole-3-acetic acid (IAA), show proteolytic activity, and inhibit phytopathogenic fungi. The best-performing strain, C1T-KM1901-B, was genomically identified as Bacillus paralicheniformis and evaluated as a bioinoculant in maize seeds under PEG-induced drought stress. Inoculation with B. paralicheniformis significantly increased germination potential and germination index of drought-resistant seeds compared to non-inoculated controls under severe drought stress conditions (40% PEG). In addition, inoculated seedlings exhibited significantly higher roots and shoot fresh and dry biomass at moderate to severe drought stress levels (15% and 20% PEG). These results are position B. paralicheniformis C1T-KM1901-B, isolated from Avicennia germinans, as a promising bioinoculant to enhance maize establishment under drought conditions. Full article

In Japan, strawberries are produced in the off-season (June to November) in cool regions; however, the high temperatures and strong sunlight limit fruit production. Dark septate endophytic fungi (DSEs) support growth and flower bud formation of plants grown in environments unsuitable for plant growth. In this study, we investigated the effects of DSE on dry matter production and flower bud formation in strawberry plants grown in the summer and autumn. The seeds were sown in soil mixed with DSE on 5 February 2024. The DSEs used were Cladophialophora chaetospira SK51 (S) and Cc. MNB12 (M), and Veronaeopsis simplex Y34 (Y). Plants were planted in a plastic house on April 18. The total dry weight was significantly increased by DSEs. This is because S and Y-cultured plants did not show a significant decrease in leaf emergence under high temperatures, unlike those grown with M; however, its leaf area was larger than that of the control. This resulted in a larger leaf area for receiving light and higher cumulative light reception and light-use efficiency. Although the DSEs increased cumulative fruit yield, the harvest period was limited to July because of the extreme summer heat. In addition, there was no difference in the budding date or flowering date between the treatments. These results suggest that DSEs improve light use efficiency, thereby increasing total dry matter weight and contributing to increased fruit yield in summer-autumn cultivation. Full article

Priestia megaterium is a maize endophyte that may help the plant defend itself against bacterial and fungal pathogens. This study aimed to identify antimicrobials produced by two P. megaterium endophytes (FS10 and FS11) from maize and determine if seed coating with either strain could increase resistance to pathogens. Volatiles emitted by both isolates reduced the hyphal growth of fungi by 17–76%. Gas chromatography analysis found that each strain emitted isovaleric acid (IVA) and 3-methyl-1-butanol (3MB). Volatiles produced by each isolate inhibited bacterial growth, especially Clavibacter michiganensis ssp. michiganensis (Cmm). IVA killed all Cmm cells at 208 µL L⁻¹, while 3MB inhibited Cmm growth by 51% at 208 µL L⁻¹. Diluted cell-free extracts from FS10 and FS11 cultures stopped growth of Cmm, Erwinia amylovora and Ustilago maydis but did not arrest growth of Fusarium verticillioides. The treatment of corn seeds with FS10 or FS11 reduced leaf damage by 38–84% in young plants caused by Bipolaris maydis, Colletotrichum graminicola (Ces.) G.W. Wilson 1914, Exserohilum turcicum and Pythium sylvaticum. FS10 and FS11 isolates exuded volatile and soluble compounds that were more effective in slowing growth of bacteria than fungi. It is likely that corn seed treatment with FS10 and FS11 triggers induced systemic resistance, which mitigates leaf damage caused by maize pathogens. Full article

Rice cadmium (Cd) contamination is a serious threat to global food security and human health. Plant-associated microbiomes are known to affect Cd accumulation in plants. However, the response of the rice microbiome to Cd contamination and its role in modulating grain Cd accumulation remain poorly understood. In the present study, the responses of the rhizospheric fungi (RF) community and seed endophytic fungi (SEF) community to the soil physiochemical properties of rice from moderately (MC) and severely (SC1 and SC2) Cd-contaminated paddies were investigated. Moreover, the effects of soil physiochemical properties, RF community and SEF community on grain Cd accumulation were analyzed through correlation analysis. The results showed that the Cd concentration in rice grains from SC2 exceeded the food safety standard of China and was higher than that of SC1 and MC. The Cd concentration in rice grains was positively correlated with the soil-available Cd concentration, while being negatively correlated with the available nutrient elements and pH value of soil. In addition, it was found that the diversity of RF increased with the soil-available Cd concentration, while the diversity and richness of SEF decreased with the soil-available Cd concentration. Moreover, the RF community was influenced by soil physiochemical properties. The Spearman correlation analysis showed that the soil-available Cd was positively correlated with RF Sebacina, Clonostachys, Acremonium, Talaromyces and Fusarium, and most of them were related to grain Cd concentration, while unclassified SEF Pleosporales and Xylariales were associated with grain Cd concentration. These results suggested that Cd stress triggered a niche-specific response of the rice fungal microbiome. The fungi related to soil Cd availability and rice grain Cd accumulation may have a great potential application in food safety production in Cd-contaminated soil. Full article

Maize (Zea mays L.) is a globally critical crop that faces numerous challenges, including contamination by mycotoxigenic fungi such as Aspergillus spp. The use of fungal endophytes as bioinoculants offers a sustainable strategy to improve plant resilience against biotic and abiotic stresses. Here, we evaluate the potential of Colletotrichum tofieldiae strain Ct0861 as a bioinoculant and its impact on maize-associated bacterial and fungal microbiomes. Field trials demonstrated that Ct0861 enhanced biomass and yield compared to controls, regardless of the application method (seed or foliar). Microbiome profiling showed that Ct0861 induced subtle, compartment-specific changes in microbial diversity and composition, while preserving the stability of core microbiome assemblages. Both microbiome data and qPCR quantification confirmed a significant reduction in Aspergillus spp. abundance in Ct0861-treated plants. Greenhouse assays corroborated these results: Ct0861 reduced A. flavus biomass by up to 90% and significantly lowered aflatoxin levels in infected grains. Dual-culture assays and the absence of Ct0861 in grain samples suggest an indirect biocontrol mechanism, potentially mediated by plant-induced resistance. This study provides the first evidence that Ct0861 acts as a biocontrol agent against mycotoxigenic Aspergillus spp. in maize. Beyond promoting plant growth, Ct0861 enhances food safety by reducing mycotoxin accumulation without disrupting the native microbiome, supporting its potential as a tool for sustainable crop protection. Full article

As an important complementation of plant genetic traits, seed endophytes (SEs) have garnered significant attention due to their crucial roles in plant germination and early seedling establishment. In this study, we employed both culture-dependent and amplicon sequencing-based approaches to characterize the endophytic microbiome in seed samples derived from different individual Panax notoginseng plants. Additionally, we evaluated the antagonistic activity of isolated culturable bacterial SEs against the root rot pathogens Fusarium solani and F. oxysporum. Our results demonstrated that a greater sampling quantity substantially increased the species richness (Observed OTUs) and diversity of seed endophytic microbiota, underscoring the importance of seed population size in facilitating the vertical transmission of diverse endophytes to progeny. The endophytic communities (including both fungi and bacteria) exhibited a conserved core microbiota alongside host-specific rare taxa, forming a phylogenetically and functionally diverse endophytic resource pool. Core bacterial genera included Streptococcus, Methylobacterium-Methylorubrum, Sphingomonas, Burkholderia-Caballeronia-Paraburkholderia, Pantoea, Halomonas, Acinetobacter, Pseudomonas, Vibrio, and Luteibacter, while core fungal genera comprised Davidiella, Thermomyces, Botryotinia, Myrothecium, Haematonectria, and Chaetomium. Among 256 isolated endophytic bacterial strains, 11 exhibited strong inhibitory effects on the mycelial growth of F. solani and F. oxysporum. Further evaluation revealed that two antagonistic strains, Bacillus cereus and B. toyonensis, significantly enhanced seed germination and plant growth in P. notoginseng, and effectively suppressed root rot disease in seedlings. These findings highlight the potential use of SEs as biocontrol agents and growth promoters in sustainable agriculture. Full article

Urochloa ruziziensis (R. Germ. and C.M. Evrard) Crins (synonym Brachiaria ruziziensis) Poales: Poaceae) pastures are often attacked by spittlebugs, compromising their biomass for livestock usage. A sustainable control method involves the use of entomopathogenic fungi. Therefore, the objective of this study was to evaluate the efficacy of controlling Mahanarva spectabilis Distant, 1909 (Hemiptera: Cercopidae), in greenhouse and field conditions via endophytic entomopathogenic fungi. In the greenhouse, the mortality of nymphs and adults was 100%, and more than 53% of the nymphs and 59% of the adults that fed on plants inoculated with Fusarium multiceps and Metarhizium anisopliae presented with these fungi in their cadavers. In the field, more than 45% of the insect cadavers that had fed on plants grown from fungus-treated seeds were found to contain the fungi. F. multiceps was found to be endophytic in more than 60% of the plants up to 90 days after seed treatment, and M. anisopliae was found in more than 70% of the plants up to 120 days after treatment. The damage scores of the control plants, both in the greenhouse and in the field, were greater than those of the plants inoculated with the fungi. F. multiceps and M. anisopliae in the endophytic pathway of U. ruziziensis are therefore efficient at controlling spittlebugs. Full article

Maize, one of the most widely cultivated crops globally, is highly susceptible to mycotoxin contamination. In this study, an endophytic strain Pseudomonas sp. HP-1, isolated from Peganum harmala L., demonstrated significant biocontrol potential. The culture extract of Pseudomonas sp. HP-1 (PHE) exhibited strong antifungal activity, with inhibition zones of 40.07 ± 0.21 mm against Penicillium italicum, 29.71 ± 0.25 mm against Aspergillus niger, and 23.10 ± 0.44 mm against A. flavus, along with notable antibacterial activity against Staphylococcus aureus (22.43 ± 0.55 mm). At a concentration of 16 mg/mL, PHE almost completely inhibited the mycelial growth of A. flavus. The antifungal mechanism of PHE was investigated through scanning electron microscopy (SEM) and propidium iodide (PI) staining analysis, which demonstrated that antifungal activity is primarily through the disruption of cellular membrane integrity. Furthermore, PHE significantly reduced the incidence of A. flavus contamination in agroecological maize seeds during storage, and treated PHE showed superior antifungal efficacy compared to non-treated PHE, highlighting its potential as an effective antifungal agent for seed protection. Through one- and two-dimensional NMR and MS analyses, the primary active compound of PHE was identified as 1-phenazinecarboxylic acid. These findings indicate that PHE can be utilized as a sustainable antifungal agent for protecting maize seeds against mycotoxin-producing fungi. Full article

Epichloë endophytic fungi are important microbial resources in agriculture and animal husbandry. Because of their stable symbiosis, species transmission, and positive effects on host plants, the use of endophytic fungi in grass breeding is of great significance. In this study, six inoculation methods were used, including the sterile seedling slit inoculation method, sterile seedling cut inoculation method, sterile seedling injection inoculation method, seed soaking inoculation method, seed piercing and then soaking inoculation method, and seed slit inoculation method. Spectrometry was used to construct new symbionts, and Liquid Chromatography–mass spectrometry was used to analyze the effects of endophytic fungi on the metabolism of new hosts. The physiological response of the new symbionts to salt and alkali stress was studied using a pot experiment. The results were as follows: In this study, Epichloë bromicola was successfully inoculated into Bromus inermis via the sterile seedling slit inoculation method, and new symbionts (EI) were obtained; the vaccination rate was 2.1%. Metabolites up-regulated by EI are significantly enriched in citrate cycle and ascorbate and aldarate metabolism, suggesting that the symbiosis of endophytic fungi indirectly triggers the production of reactive oxygen species (ROS) through multiple metabolic pathways. The saline–alkali stress test showed that the host antioxidant system was active after inoculation, and the total antioxidant capacity was significantly increased compared with non-symbionts (EF) under mild stress (p < 0.05), which provided important clues to reveal the complex mechanism of plant–fungus symbiosis. This study provides practical guidance and a theoretical basis for plant adaptation under climate change, health management of grass seeds, and soil improvement through endophytic fungi. Full article

The screening of exopolysaccharides (EPS) produced by 52 isolates of endophytic and basidiomycete fungi was studied on two different media, PDB and PYGM. There were five isolates that could produce dried exopolysaccharide of more than 4 g/L (S. commune LF01962, LF01001, LF01581, Pycnoporus sp. MMCR00271.1, Pestalotiopsis sp. PP0005). The molecular weights of these exopolymers were found to be in the range of 2.5–500 kDa. These five exopolysaccharides, produced by five different fungal isolates, showed non-cytotoxic activity against NCTC clone 929 and HDFn cell lines. The selected fungal isolate of S. commune LF01962 was used for further optimization of different medium compositions affecting exopolysaccharide production using statistical methods. Among four conditions tested in the first step (xylose + peptone, glucose + (NH₄)₂HPO₄, fructose + peptone, and mannose + yeast extract), mannose + yeast extract resulted in the highest exopolysaccharide production of 5.10 ± 2.00 g/L. In the second step using Plackett–Burman design, the optimal medium for S. commune exopolysaccharide production was found to consist of 40 g/L glucose, 5 g/L mannose, 20 g/L (NH₄)₂HPO₄, 5 g/L yeast extract, 3 g/L monosodium glutamate, 0.5 g/L KH₂PO₄, 0.5 g/L K₂HPO₄, 0.2 g/L MgSO₄, 1 mL/L trace elements, and 3 mL/L vitamin solution, which resulted in 8.16 g/L exopolysaccharide production. Exopolysaccharide production in a 5 L bioreactor using small pellets as seed inoculum was found to produce 18.28 g/L exopolysaccharide. Full article

Perennial ryegrass is an important temperate grass used for forage and turf worldwide. It forms symbiotic relationships with endophytic fungi (endophytes), conferring pasture persistence and resistance to herbivory. Endophyte performance can be influenced by the host genotype, as well as environmental factors such as seed storage conditions. It is therefore critical to confirm seed quality and purity before a seed is sown. DNA-based methods are often used for quality control purposes. Recently, near-infrared spectroscopy (NIRS) coupled with hyperspectral imaging was used to discriminate perennial ryegrass cultivars and endophyte presence in individual seeds. Here, a NIRS-based analysis of bulk seeds was used to develop models for discriminating perennial ryegrass cultivars (Alto, Maxsyn, Trojan and Bronsyn), each hosting a suite of eight to eleven different endophyte strains. Sub-sampling, six per bag of seed, was employed to minimize misclassification error. Using a nested PLS-DA approach, cultivars were classified with an overall accuracy of 94.1–98.6% of sub-samples, whilst endophyte presence or absence was discriminated with overall accuracies between 77.8% and 96.3% of sub-samples. Hierarchical classification models were developed to discriminate bulked seed samples quickly and easily with minimal misclassifications of cultivars (<8.9% of sub-samples) or endophyte status within each cultivar (<11.3% of sub-samples). In all cases, greater than four of the six sub-samples were correctly classified, indicating that innate variation within a bag of seeds can be overcome using this strategy. These models could benefit turf- and pasture-based industries by providing a tool that is easy, cost effective, and can quickly discriminate seed bulks based on cultivar and endophyte content. Full article

Endophytic fungi possess a unique ability to produce abundant secondary metabolites, which play an active role in the growth and development of host plants. In this study, chemical investigations on the endophytic fungus Aspergillus japonicus TE-739D derived from the cultivated tobacco (Nicotiana tabacum L.) afforded two new polyketide derivatives, namely japoniones A (1) and B (2), as well as four previously reported compounds 3–6. Their chemical structures were elucidated by detailed spectroscopic analyses and quantum chemical calculations. In the herbicidal assays on the germination and radicle growth of Amaranthus retroflexus L. and Eleusine indica seeds, compound 1 was found to inhibit the germ and radicle elongation. Notably, compound 2 showed potent herbicidal activity against A. retroflexus L. germ elongation, with an IC₅₀ value of 43.6 μg/mL, even higher than the positive control glyphosate (IC₅₀ = 76.0 μg/mL). Moreover, compound 4 demonstrated strong antibacterial effects against the pathogens Bacillus cereus and Bacillus subtilis, with a comparable MIC value of 16 μg/mL to the positive control chloramphenicol. These findings indicate that the endophytic fungus A. japonicus TE-739D holds significant metabolic potential to produce bioactive secondary metabolites, which are beneficial, providing survival value to the host plants. Full article

Many endophytic fungi are approved as plant growth stimulants, and several commercial biostimulants have already been introduced in agricultural practice. However, there are still many species of fungi whose plant growth-promoting properties have been understudied or not studied at all. We examined the growth-promoting effect in spring barley (Hordeum vulgare) and Italian ryegrass (Lolium multiflorum) induced by three endophytic fungi previously obtained from the roots of Festuca/Lolium grasses. Surface-sterilized seeds were inoculated with a spore suspension of Cadophora fastigiata (isolate BSG003), Paraphoma fimeti (BSG010), Plectosphaerella cucumerina (BSG006), and their spore mixture. Before harvesting, the inoculated plants were grown in a greenhouse, with the barley being in multi-cavity trays for 30 days and ryegrass being placed in an original cylindric element system for 63 days. All three newly tested fungi had a positive effect on the growth of the barley and ryegrass plants, with the most pronounced impact observed in their root size. The fungal inoculations increased the dry shoot biomass between 11% and 26% in Italian ryegrass, but no such impact was observed in barley. The highest root increment was observed in barley. Herein, P. cucumerina and C. fastigiata inoculations were superior to other treatments, showing an increase in root dry weight of 50% compared to 20%, respectively. All fungal inoculations significantly promoted root growth in Italian ryegrass, resulting in a 20–30% increase in dry weight compared to non-inoculated plants. Moreover, a strong stimulatory effect of the fungi-emitted VOCs on the root development was observed in plate-in-plate arrays. In the presence of C. fastigiata and P. cucumerina cultures, the number of roots and root hairs in barley seedlings doubled compared to control plants. Thus, in our study, we demonstrated the potential of the grass root-derived endophytes C. fastigiata, P. fimeti, and P. cucumerina as growth promoters for spring barley and Italian ryegrass. These studies can be extended to other major crops and grasses by evaluating different fungal isolates. Full article

Microbial biostimulants that promote plant growth and abiotic stress tolerance are promising alternatives to chemical fertilizers and pesticides. Although Trichoderma fungi are known biocontrol agents, their biostimulatory potential has been scarcely studied in field conditions. Here, the mixture of two endophytic Trichoderma strains (Trichoderma afroharzianum TR04 and Trichoderma simmonsii TR05) was tested as biostimulant in the form of foliar spray on young (BBCH 15-16) maize (5.7 ha) and sunflower (5.7 and 11.3 ha) fields in Hungary. The stimulatory effect was characterized by changes in plant height, the number of viable leaves, and the chlorophyll content, combined with yield sensor collected harvest data. In all trials, the foliar treatment with Trichoderma spores increased photosynthetic potential: the number of viable leaves increased by up to 6.7% and the SPAD index by up to 19.1% relative to the control. In extreme drought conditions, maize yield was doubled (from 0.587 to 1.62 t/ha, p < 0.001). The moisture content of the harvested seeds, as well as sunflower height, consistently increased post-treatment. We concluded that foliar spraying of young plants with well-selected endophytic Trichoderma strains can stimulate growth, photosynthesis, and drought tolerance in both monocot maize and dicots sunflower crops in field conditions. Full article

Endophytic microbes in medicinal plants often possess beneficial traits for plant health. This study focuses on the bacterial endophyte strain B.L.Ns.14, isolated from Nigella sativa leaves, which demonstrated multiple plant growth-promoting properties. In vitro tests showed that B.L.Ns.14 supports plant growth, colonization, and tolerance to abiotic stress. The strain also exhibited antifungal activity against phytopathogens such as Rhizoctonia solani, Colletotrichum acutatum, Verticillium dahliae, and Fusarium oxysporum f. sp. radicis-lycopersici. Whole-genome analysis, supported by ANI and dDDH values, identified B.L.Ns.14 as Bacillus halotolerans. Genome mining revealed 128 active carbohydrate enzymes (Cazymes) related to endophytism and biocontrol functions, along with genes involved in phosphate solubilization, siderophore and IAA production, biofilm formation, and motility. Furthermore, genes for osmolyte metabolism, Na+/H+ antiporters, and stress response proteins were also identified. The genome harbors 12 secondary metabolite biosynthetic gene clusters, including those for surfactin, plipastatin mojavensin, rhizocticin A, and bacilysin, known for their antagonistic effects against fungi. Additionally, B.L.Ns.14 promoted Arabidopsis thaliana growth under both normal and saline conditions, and enhanced Solanum lycopersicum growth via seed biopriming and root irrigation. These findings suggest that Bacillus halotolerans B.L.Ns.14 holds potential as a biocontrol and plant productivity agent, warranting further field testing. Full article