Tolerance of Trichoderma sp. to Heavy Metals and its Antifungal Activity in Algerian Marine Environment

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.

Trichoderma and Nanotechnology in Sustainable Agriculture: A Review

Due to their unique properties and functionalities, nanomaterials can be found in different activities as pharmaceutics, cosmetics, medicine, and agriculture, among others. Nowadays, formulations with nano compounds exist to reduce the application of conventional pesticides and fertilizers. Among the most used are nanoparticles (NPs) of copper, zinc, or silver, which are known because of their cytotoxicity, and their accumulation can change the dynamic of microbes present in the soil. In agriculture, Trichoderma is widely utilized as a safe biocontrol strategy and to promote plant yield, making it susceptible to be in contact with nanomaterials that can interfere with its viability as well as its biocontrol and plant growth promotion effects. It is well-known that strains of Trichoderma can tolerate and uptake heavy metals in their bulk form, but it is poorly understood whether the same occurs with nanomaterials. Interestingly, Trichoderma can synthesize NPs that exhibit antimicrobial activities against various organisms of interest, including plant pathogens. In this study, we summarize the main findings regarding Trichoderma and nanotechnology, including its use to synthesize NPs and the consequence that these compounds might have in this fungus and its associations. Moreover, based on these findings we discuss whether it is feasible to develop agrochemicals that combine NPs and Trichoderma strains to generate more sustainable products or not.

Isolation and Characterization of Nickel-Tolerant Trichoderma Strains from Marine and Terrestrial Environments

Nickel contamination is a serious environmental issue that requires immediate action. In this study, 23 strains of Trichoderma were isolated from terrestrial and marine environments and identified using a polyphasic approach of morphological characterization and ITS gene sequence analysis. The Trichoderma strains were tested for their tolerance and biosorption of nickel. Our results showed the growth of all Trichoderma strains on Trichoderma Selective Medium (TSM) with 50–1200-ppm nickel, indicating their tolerance of this heavy metal even at a relatively high concentration. Six Trichoderma strains (three isolated from terrestrial substrates and three from marine substates) had the highest radial growth on TSM with 50-ppm Ni. Among these fungal isolates, Trichoderma asperellum (S03) isolated from soil exhibited the best growth after 2 days of incubation. For the biosorption of nickel, the accumulation or uptake efficiency by the six selected Trichoderma was determined in Potato Dextrose Broth (PDB) supplemented with 50-ppm Ni using a Flame Atomic Absorption Spectrophotometer (AAS). The percent uptake efficiency of the three strains of T. asperellum (S03, S08, and LL14) was computed to be up to 66%, while Trichoderma virens (SG18 and SF22) and Trichoderma inhamatum (MW25) achieved up to 68% uptake efficiency. Observation of the Trichoderma strains with Scanning Electron Microscopy (SEM) before and after the absorption of nickel showed very minimal damage on the hyphal and conidial surface morphology, but changes in the colonial characteristics were observed. Our study highlighted the potential of terrestrial and marine strains of Trichoderma for the bioremediation of nickel pollution.

Arsenic Accumulation in Hydroponically Grown Schizachyrium scoparium (Little Bluestem) Amended with Root-Colonizing Endophytes

We integrated microscopy, spectroscopy, culturing and molecular biology, and aqueous chemistry techniques to evaluate arsenic (As) accumulation in hydroponically grown Schizachyrium scoparium inoculated with endophytic fungi. Schizachyrium scoparium grows in historically contaminated sediment in the Cheyenne River Watershed and was used for laboratory experiments with As(V) ranging from 0 to 2.5 mg L^-1 at circumneutral pH. Arsenic accumulation in regional plants has been a community concern for several decades, yet mechanisms affecting As accumulation in plants associated with endophytic fungi remain poorly understood. Colonization of roots by endophytic fungi supported better external and vascular cellular structure, increased biomass production, increased root lengths and increased P uptake, compared to noninoculated plants (p value <0.05). After exposure to As(V), an 80% decrease of As was detected in solution and accumulated mainly in the roots (0.82-13.44 mg kg^-1) of noninoculated plants. Endophytic fungi mediated intracellular uptake into root cells and translocation of As. Electron microprobe X-ray mapping analyses detected Ca-P and Mg-P minerals with As on the root surface of exposed plants, suggesting that these minerals could lead to As adsorption on the root surface through surface complexation or coprecipitation. Our findings provide new insights regarding biological and physical-chemical processes affecting As accumulation in plants for risk assessment applications and bioremediation strategies.

Bioprospecting of Rhizosphere-Resident Fungi: Their Role and Importance in Sustainable Agriculture

Rhizosphere-resident fungi that are helpful to plants are generally termed as 'plant growth promoting fungi' (PGPF). These fungi are one of the chief sources of the biotic inducers known to give their host plants numerous advantages, and they play a vital role in sustainable agriculture. Today's biggest challenge is to satisfy the rising demand for crop protection and crop yield without harming the natural ecosystem. Nowadays, PGPF has become an eco-friendly way to improve crop yield by enhancing seed germination, shoot and root growth, chlorophyll production, and fruit yield, etc., either directly or indirectly. The mode of action of these PGPF includes the solubilization and mineralization of the essential micro- and macronutrients needed by plants to regulate the balance for various plant processes. PGPF produce defense-related enzymes, defensive/volatile compounds, and phytohormones that control pathogenic microbes' growth, thereby assisting the plants in facing various biotic and abiotic stresses. Therefore, this review presents a holistic view of PGPF as efficient natural biofertilizers to improve crop plants' growth and resistance.

Dynamic interactions of Trichoderma harzianum TS 143 from an old mining site in Turkey for potent metal(oid)s phytoextraction and bioenergy crop farming

Despite high pollution risk, the termination of mining practices is not in question in the current era in line with the growing needs of beings. Instead, the rehabilitation by phytoremediation restores the economic and aesthetic values of the damaged locale. Here, potentially toxic elements (PTEs) tolerant 29 Trichoderma isolates from mining sites located foothills of Turkey`s NE Black Sea coast were isolated. The highest tolerant strain (As 1400 mg L^-1, Cd 1200 mg L^-1, Cu 2000 mg L^-1, Pb 2100 mg L^-1, Zn 3000 mg L^-1) was characterized with translation elongation factor1 alpha (tef-1α) barcode and deposited in the GenBank. The PTEs removal strength of novel Trichoderma harzianum TS143 was highest for Pb (58%) and the lowest for As (8.5%) in the order of Pb > Cd > Cu > Zn > As. While bioleaching capacity was highest in Cd with 30%, the lowest was for As (8%). TS143 was found remarkably effective on all the physicochemical parameters in the shoot and root tissues of maize. The increase in the carbohydrate content (33.50%) proves the potential usage of the contaminated maize plants in bioenergy production. Core sustainable agents with their mesh type robust hyphal structure enfolding PTEs such as TS143 contribute to the phytoremediation technology along with potential plant biomass management for the biodiesel industry.