Mycoremediation effect of Trichoderma harzianum strain T22 combined with ozonation in diesel-contaminated sand

Lessons from the field: Trichoderma in agriculture and human health

The use of Trichoderma in agriculture as both a biocontrol agent and biofertilizer hinges on its ability to colonize the rhizosphere, promote plant growth, endure adverse environments, compete for space and nutrients, and produce enzymes and secondary metabolites to mycoparasitize and infect other fungus. In humans, Trichoderma exhibits the capacity to infect various bodily tissues, leading to Trichodermosis. There has been a notable increase in cases ranging from superficial to fatal, invasive, and disseminated infections, particularly among immunocompromised individuals. Trichoderma species employ diverse strategies to colonize and survive in various environments, infecting phytopathogens; however, the mechanisms and virulence factors contributing to human infections remain poorly understood. In this mini review, we provide a brief overview and contextualization of the virulence mechanisms employed by Trichoderma in parasitizing other fungi, as well as those implicated in modulating plant immunity and inducing human infections. Furthermore, we discuss the similarity of these virulence factors capable of modulating the mammalian immune system and their potential implications for human infection.

Indigenous fungi with the ability to biodegrade hydrocarbons in diesel-contaminated soil are isolated and selected using a simple methodology

Soil contamination by hydrocarbons is a problem that causes severe damage to the environment and public health. Technologies such as bioremediation using native microbial species represent a promising and environmentally friendly alternative for decontamination. This study aimed to isolate indigenous fungi species from the State of Rio de Janeiro, Brazil and evaluate their diesel degrading capacity in soils contaminated with crude oil. Seven filamentous fungi were isolated after enrichment cultivation from soils collected from contaminated sites and subjected to growth analysis on diesel nutrient media. Two fungal species were pre-selected and identified by morphological genus analysis and molecular techniques as Trichoderma asperellum and Penicillium pedernalense. The microdilution test showed that T. asperellum presented better fungal growth in high diesel concentrations than P. pedernalense. In addition, T. asperellum was able to degrade 41 and 54% of the total petroleum hydrocarbon (TPH) content present in soil artificially contaminated with diesel (10 g/kg of soil) in 7 and 14 days of incubation, respectively. In higher diesel concentration (1000 g of diesel/kg of soil) the TPH degradation reached 26%, 45%, and 48%, in 9, 16, and 30 d, respectively. The results demonstrated that the selected species was suitable for diesel degradation. We can also conclude that the isolation and selection process proposed in this work was successful and represents a simple alternative for obtaining native species with hydrocarbon degradation capacity, for use in the bioremediation process in the recovery of contaminated areas in an ecologically acceptable way.

Counter-attack of biocontrol agents: Environmentally benign Approaches against Root-knot nematodes (Meloidogyne spp.) on Agricultural crops

Root-knot nematodes (Meloidogyne spp.) are obligate sedentary endoparasites, considered severe crop-damaging taxa among all plant-parasitic nematodes globally. Their attacks through parasitic proteins alter the physiology and machinery of the host cells to favour parasitism and reduction in crop yield. Currently, the use of excessive pesticides as a fast remedy to manage this pest is hazardous for both the environment and humans. Keeping this view in mind, there is an urgent need for developing efficient eco-friendly strategies. Bio-control as an eco-friendly is considered the best approach to manage nematodes without disturbing non-target microbes. In bio-control, living agents such as fungi and bacteria are the natural enemies of nematodes and the best substitute for pesticides. Fungi, including nematode-trapping fungi, can sense host signals and produce special trapping devices viz., constricting rings and adhesive knobs/loops, to capture nematodes and kill them. Whereas, endo-parasitic fungi kill nematodes by enzymatic secretions and spore adhesion through their hyphae. Bacteria can also control nematodes by producing antibiotic compounds, competing for nutrients and rhizosphere, production of hydrolytic enzymes viz., chitinases, proteases, lipases, and induction of systemic resistance (ISR) in host plants. Scientists throughout the world are trying to evolve environmentally benign methods that sustain agricultural production and keep nematodes below a threshold level. Whatever methods evolve, in the future the focus should be on important aspects like green approaches for managing nematodes without disturbing human health and the environment.

[Ecological and biological benefits of the cosmopolitan fungus Trichoderma spp. in agriculture: A perspective in the Mexican countryside]

There is currently an extensive record of scientific studies on the general characteristics of filamentous fungus Trichoderma spp., which demonstrates its wide range of interrelation in ecosystems and its fungal activity that benefits the agricultural sector and agroindustry, as well as its importance in the preservation and restoration of the soil microbiota. The success of the biological and ecological benefits of Trichoderma is due to its reproductive capacity, as well as its efficiency in the use of soil nutrients; the efficacy of the genus has been reported against a variety of phytopathogenic fungi, as well as the potential to synthesize and release enzymes (cellulases, xylanases, and chitinases) that have been implemented in agroindustrial bioprocesses. It has also been reported that various species of Trichoderma spp. can produce auxins and gibberellin-type growth regulators, reported as growth promoters of some agricultural crops; however, their most relevant fact is their ability to prevail at certain doses of 'agrotoxic' active ingredients and contribute studies regarding processes for obtaining biofuel and bioremediation of the agricultural soil. In this overview, a general description of the current and relevant studies of the different subspecies of Trichoderma and their contribution in agriculture is made, presenting results obtained in vitro, in greenhouses and in the field. This analysis will serve as a starting point for future research in Mexico, specifically on the genus Trichoderma and its benefits for the Mexican countryside.

Fungal bioproducts for petroleum hydrocarbons and toxic metals remediation: recent advances and emerging technologies

Petroleum hydrocarbons and toxic metals are sources of environmental contamination and are harmful to all ecosystems. Fungi have metabolic and morphological plasticity that turn them into potential prototypes for technological development in biological remediation of these contaminants due to their ability to interact with a specific contaminant and/or produced metabolites. Although fungal bioinoculants producing enzymes, biosurfactants, polymers, pigments and organic acids have potential to be protagonists in mycoremediation of hydrocarbons and toxic metals, they can still be only adjuvants together with bacteria, microalgae, plants or animals in such processes. However, the sudden accelerated development of emerging technologies related to the use of potential fungal bioproducts such as bioinoculants, enzymes and biosurfactants in the remediation of these contaminants, has boosted fungal bioprocesses to achieve higher performance and possible real application. In this review, we explore scientific and technological advances in bioprocesses related to the production and/or application of these potential fungal bioproducts when used in remediation of hydrocarbons and toxic metals from an integral perspective of biotechnological process development. In turn, it sheds light to overcome existing technological limitations or enable new experimental designs in the remediation of these and other emerging contaminants.

Isolation of the Main Pathogens Causing Postharvest Disease in Fresh Angelica sinensis during Different Storage Stages and Impacts of Ozone Treatment on Disease Development and Mycotoxin Production

Angelica sinensis, a Chinese herbal medicine, is susceptible to molds during storage, reducing its quality, and even generating mycotoxins with toxic effects on human health. Fresh A. sinensis was harvested from Min County of Gansu Province in China and kept at room temperature. Naturally occurring symptoms were observed during different storage stages. Molds were isolated and identified from the diseased A. sinensis using morphological and molecular biology methods. The impact of ozone treatment on postharvest disease development and mycotoxin production was investigated. The results indicated that A. sinensis decay began on day 7 of storage and progressed thereafter. Nine mold species were isolated and characterized: day 7, two Mucormycetes; day 14, Clonostachys rosea; day 21, two Penicillium species and Aspergillus versicolor; day 28, Alternaria alternata and Trichoderma atroviride; and day 49, Fusarium solani. Ozone treatment markedly inhibited the development of postharvest disease and the mycotoxin production (such as, patulin, 15-acetyl-deoxynivalenol, and sterigmatocystin) in the rotten tissue of A. sinensis inoculated with the nine isolates.

Spectroscopic Analyses and Antimicrobial Activity of Novel Ciprofloxacin and 7-Hydroxy-4-methylcoumarin, the Plant-Based Natural Benzopyrone Derivative

Coumarin is highly distributed in nature, notably in higher plants. The biological features of coumarin include antibacterial, anticancer and antioxidant effects. It is well known that metal ions present in complexes accelerate the drug action and the efficacy of organic therapeutic agents. The main aim of the current study is the synthesis of different complexes of the interaction between ciprofloxacin hydrochloride (CIP) and coumarin derivative 7-hydroxy-4-methylcoumarin (HMC) with Zr(IV). The chelates of CIP with Zr(IV) were prepared and characterized by elemental analysis, melting point, conductance measurements, spectroscopic techniques involving IR, UV-Vis, ¹H NMR, and thermal behavior (TG-DTG) in the presence of HMC, dimethylformamide (DMF), pyridine (Py), and triethylamine (Et₃N). Results of molar conductivity tests showed that the new synthesized complexes are electrolytes with a 1:1 or 1:2 electrolyte ratio, with the chloride ions functioning as counter ions. According to IR spectra, CIP acts as a neutral bidentate ligand with Zr(IV) through one carboxylato oxygen and the carbonyl group, HMC as a monodentate through the carbonyl group, and DMF through the oxygen atom of the carbonyl group and the N atom of Py and Et₃N. The thermal behavior of the complexes was carefully investigated using TG and DTG techniques. TG findings signal that water molecules are found as hydrated and coordinated. The thermal decomposition mechanisms proposed for CIP, HMC, and Zr(IV) complexes are discussed and the activation energies (E_a), Gibbs free energies (∆G*), entropies (∆S*), and enthalpies (∆H*) of thermal decomposition reactions have been calculated using Coats–Redfern (CR) and Horowitz–Metzeger (HM) methods. The studied complexes were tested against some human pathogens and phytopathogens, including three Gram-positive bacteria (Bacillus subtilis, B. cereus, Brevibacterium otitidis) and three Gram-negative bacteria (Escherichiacoli, Pseudomonas aeruginosa and Klebsiella pneumoniae), and compared to the free CIP and HMC parent compounds.

Rhizospheric Actinomycetes Revealed Antifungal and Plant-Growth-Promoting Activities under Controlled Environment

Actinomycetes has large habitats and can be isolated from terrestrial soil, rhizospheres of plant roots, and marine sediments. Actinomycetes produce several bioactive secondary metabolites with antibacterial, antifungal, and antiviral properties. In this study, some Actinomycetes strains were isolated from the rhizosphere zone of four different plant species: rosemary, acacia, strawberry, and olive. The antagonistic activity of all isolates was screened in vitro against Escherichia coli and Bacillus megaterium. Isolates with the strongest bioactivity potential were selected and molecularly identified as Streptomyces sp., Streptomyces atratus, and Arthrobacter humicola. The growth-promoting activity of the selected Actinomycetes isolates was in vivo evaluated on tomato plants and for disease control against Sclerotinia sclerotiorum. The results demonstrated that all bacterized plants with the studied Actinomycetes isolates were able to promote the tomato seedlings' growth, showing high values of ecophysiological parameters. In particular, the bacterized seedlings with Streptomyces sp. and A. humicola showed low disease incidence of S. sclerotiorum infection (0.3% and 0.2%, respectively), whereas those bacterized with S. atratus showed a moderate disease incidence (7.6%) compared with the positive control (36.8%). In addition, the ability of the studied Actinomycetes to produce extracellular hydrolytic enzymes was verified. The results showed that A. humicola was able to produce chitinase, glucanase, and protease, whereas Streptomyces sp. and S. atratus produced amylase and pectinase at high and moderate levels, respectively. This study highlights the value of the studied isolates in providing bioactive metabolites and extracellular hydrolytic enzymes, indicating their potential application as fungal-biocontrol agents.

Trichoderma: An Eco-Friendly Source of Nanomaterials for Sustainable Agroecosystems

Traditional nanoparticle (NP) synthesis methods are expensive and generate hazardous products. It is essential to limit the risk of toxicity in the environment from the chemicals as high temperature and pressure is employed in chemical and physical procedures. One of the green strategies used for sustainable manufacturing is microbial nanoparticle synthesis, which connects microbiology with nanotechnology. Employing biocontrol agents Trichoderma and Hypocrea (Teleomorphs), an ecofriendly and rapid technique of nanoparticle biosynthesis has been reported in several studies which may potentially overcome the constraints of the chemical and physical methods of nanoparticle biosynthesis. The emphasis of this review is on the mycosynthesis of several metal nanoparticles from Trichoderma species for use in agri-food applications. The fungal-cell or cell-extract-derived NPs (mycogenic NPs) can be applied as nanofertilizers, nanofungicides, plant growth stimulators, nano-coatings, and so on. Further, Trichoderma-mediated NPs have also been utilized in environmental remediation approaches such as pollutant removal and the detection of pollutants, including heavy metals contaminants. The plausible benefits and pitfalls associated with the development of useful products and approaches to trichogenic NPs are also discussed.

The Antifungal Effects of Citral on Magnaporthe oryzae Occur via Modulation of Chitin Content as Revealed by RNA-Seq Analysis

The natural product citral has previously been demonstrated to possess antifungal activity against Magnaporthe oryzae. The purpose of this study was to screen and annotate genes that were differentially expressed (DEGs) in M. oryzae after treatment with citral using RNA sequencing (RNA-seq). Thereafter, samples were reprepared for quantitative real-time PCR (RT-qPCR) analysis verification of RNA-seq data. The results showed that 649 DEGs in M. oryzae were significantly affected after treatment with citral (100 μg/mL) for 24 h. Kyoto Encyclopedia of Genes and Genomes (KEGG) and a gene ontology (GO) analysis showed that DEGs were mainly enriched in amino sugar and nucleotide sugar metabolic pathways, including the chitin synthesis pathway and UDP sugar synthesis pathway. The results of the RT-qPCR analysis also showed that the chitin present in M. oryzae might be degraded to chitosan, chitobiose, N-acetyl-D-glucosamine, and β-D-fructose-6-phosphate following treatment with citral. Chitin degradation was indicated by damaged cell-wall integrity. Moreover, the UDP glucose synthesis pathway was involved in glycolysis and gluconeogenesis, providing precursors for the synthesis of polysaccharides. Galactose-1-phosphate uridylyltransferase, which is involved in the regulation of UDP-α-D-galactose and α-D-galactose-1-phosphate, was downregulated. This would result in the inhibition of UDP glucose (UDP-Glc) synthesis, a reduction in cell-wall glucan content, and the destruction of cell-wall integrity.

Chemical Composition and Antimicrobial Properties of Mentha × piperita cv. 'Kristinka' Essential Oil

Several economically important crops, fruits and vegetables are susceptible to infection by pathogenic fungi and/or bacteria postharvest or in field. Recently, plant essential oils (EOs) extracted from different medicinal and officinal plants have had promising antimicrobial effects against phytopathogens. In the present study, the potential microbicide activity of Mentha × piperita cv. ‘Kristinka’ (peppermint) EO and its main constituents have been evaluated against some common phytopathogens. In addition, the cell membrane permeability of the tested fungi and the minimum fungicidal concentrations were measured. The antifungal activity was tested against the following postharvest fungi: Botrytis cinerea, Monilinia fructicola, Penicillium expansum and Aspergillus niger, whereas antibacterial activity was evaluated against Clavibacter michiganensis, Xanthomonas campestris, Pseudomonas savastanoi and P. syringae pv. phaseolicola. The chemical analysis has been carried out using GC-MS and the main components were identified as menthol (70.08%) and menthone (14.49%) followed by limonene (4.32%), menthyl acetate (3.76%) and β-caryophyllene (2.96%). The results show that the tested EO has promising antifungal activity against all tested fungi, whereas they demonstrated only a moderate antibacterial effect against some of the tested bacteria.

Biochemical Characterization, Phytotoxic Effect and Antimicrobial Activity against Some Phytopathogens of New Gemifloxacin Schiff Base Metal Complexes

String of Fe(III), Cu(II), Zn(II) and Zr(IV) complexes were synthesized with tetradentateamino Schiff base ligand derived by condensation of ethylene diamine with gemifloxacin. The novel Schiff base (4E,4'E)-4,4'-(ethane-1,2-diyldiazanylylidene)bis{7-[(4Z)-3-(aminomethyl)-4-(methoxyimino)pyrrolidin-1-yl]-1-cyclopropyl-6-fluoro-1,4-dihydro-1,8-naphthyridine-3-carboxylic acid} (GMFX-en) and its metal complexes were identified and confirmed by elemental analyses, FT-IR, UV/VIS, ¹ H-NMR spectra, magnetic susceptibility, conductometric measurements and thermal analyses. The FT-IR spectral data showed the chelation behavior of GMFX-en toward the metal ions through oxygen of carboxylate group and nitrogen of azomethine group. In the light of all spectral data, these complexes presumably have octahedral geometry configurations. Thermal analysis specified that the decaying of the metal complexes exist in two or three steps with the final residue metal oxides. Antimicrobial activity of the new prepared metal complexes was screened against some common phytopathogens and their mode of action has been also discussed. The potential phytotoxic effectiveness of the new complexes was furthermore inspected on two commonly experimental plants. The complexes showed significant antimicrobial and phytotoxic effects against the majority of tested phytopathogens and the two tested plants, respectively. The potential antimicrobial activity of the complexes proved their possibility to be used successfully in agropharmacutical industry to control many serious phytopathogens. The phytotoxicity of the studied complexes also indicated their possibility as potential bio-based herbicides alternatives to weed control in crop fields.

Biological Activities of Some New Secondary Metabolites Isolated from Endophytic Fungi: A Review Study

Secondary metabolites isolated from plant endophytic fungi have been getting more and more attention. Some secondary metabolites exhibit high biological activities, hence, they have potential to be used for promising lead compounds in drug discovery. In this review, a total of 134 journal articles (from 2017 to 2019) were reviewed and the chemical structures of 449 new metabolites, including polyketides, terpenoids, steroids and so on, were summarized. Besides, various biological activities and structure-activity relationship of some compounds were aslo described.

Study of Bio-Pharmaceutical and Antimicrobial Properties of Pomegranate (Punica granatum L.) Leathery Exocarp Extract

Pomegranate (Punica granatum L.) fruits are important sources of vitamins and minerals and widely used in the dietary supplement industry. An aqueous extract of its leathery exocarp (LEP) was obtained by a solid-phase micro-extraction method. The antifungal activity was examined against the phytopathogenic fungi, Fusarium oxysporum, Phytophthora cinnamomi, Penicillium digitatum and Botrytis cinerea, and the antibacterial activity was evaluated against Escherichia coli, Xanthomonas campestris,Bacillus megaterium and Clavibacter michiganensis. The antimicrobial assays showed, in some cases, a promising antimicrobial effect compared to the synthetic drugs. The possible anti-acetylcholinesterase and antioxidant activities of the LEP extract were investigated by the Ellman’s assay and 2,2-diphenyl-1-picrylhydrazyl (DPPH) test, respectively, and their results showed that the LEP extract has an effective anti-acetylcholinesterase inhibitory effect and an antioxidant activity. Thus, the LEP extract could be valid as a candidate for further studies on the use of pomegranate in neurodegenerative diseases as a food preservative and a suitable substitute to control several phytopathogens.