Mineral Biofortification and Growth Stimulation of Lentil Plants Inoculated with Trichoderma Strains and Metabolites

Biofortification of crops via agricultural interventions represents an excellent way to supply micronutrients in poor rural populations, who highly suffer from these deficiencies. Soil microbes can directly influence plant growth and productivity, e.g., by contrasting plant pathogens or facilitating micronutrient assimilation in harvested crop-food products. Among these microbial communities, Trichoderma fungi are well-known examples of plant symbionts widely used in agriculture as biofertilizers or biocontrol agents. In this work, eleven Trichoderma strains and/or their bioactive metabolites (BAMs) were applied to lentil plants to evaluate their effects on plant growth and mineral content in greenhouse or field experiments. Our results indicated that, depending upon the different combinations of fungal strain and/or BAM, the mode of treatment (seed and/or watering), as well as the supplementary watering with solutions of iron (Fe) and zinc (Zn), the mineral absorption was differentially affected in treated plants compared with the water controls. In greenhouse conditions, the largest increase in Fe and Zn contents occurred when the compounds were applied to the seeds and the strains (in particular, T. afroharzianum T22, T. harzianum TH1, and T. virens GV41) to the soil. In field experiments, Fe and Zn contents increased in plants treated with T. asperellum strain KV906 or the hydrophobin HYTLO1 compared with controls. Both selected fungal strains and BAMs applications improved seed germination and crop yield. This biotechnology may represent an important challenge for natural biofortification of crops, thus reducing the risk of nutrient deficiencies.

The Biocontrol Potential of Endophytic Trichoderma Fungi Isolated from Hungarian Grapevines. Part I. Isolation, Identification and In Vitro Studies

This paper reports on the identification and in vitro characterization of several Trichoderma strains isolated from the Tokaj Wine Region in North-East Hungary. Ten isolates were analyzed and found to consist of six individual species—T. gamsii, T. orientale, T. simmonsii, T. afroharzianum, T. atrobrunneum and T. harzianum sensu stricto. The growth potential of the strains was assessed at a range of temperatures. We also report here on the in vitro biocontrol properties and fungicide tolerance of the most promising strains.

Context-Dependent Effects of Trichoderma Seed Inoculation on Anthracnose Disease and Seed Yield of Bean (Phaseolus vulgaris): Ambient Conditions Override Cultivar-Specific Differences

Root colonizing Trichoderma fungi can stimulate plant immunity, but net effects are strain × cultivar-specific and changing ambient conditions further contribute to variable outcomes. Here, we used four Trichoderma spp. to inoculate seeds of four common bean (Phaseolus vulgaris) cultivars and explored in three different experimental setups the effects on fungal anthracnose after leaf inoculation with Colletotrichum lindemuthianum. Plants growing in pots with field soil under greenhouse conditions exhibited the highest and those in the open field the lowest overall levels of disease. Among 48 Trichoderma strain × bean cultivar × setup combinations, Trichoderma-inoculation enhanced disease in six and decreased disease in ten cases, but with the exception of T. asperellum B6-inoculated Negro San Luis beans, the strain × cultivar-specific effects on anthracnose severity differed among the setups, and anthracnose severity did not predict seed yield in the open field. In the case of Flor de Mayo beans, Trichoderma even reduced yield in anthracnose-free field plots, although this effect was counterbalanced in anthracnose-infected plots. We consider our work as a case study that calls for stronger emphasis on field experiments in the early phases of screenings of Trichoderma inoculants as plant biostimulants.

Optimization of Cadmium Ions Biosorption Onto Trichoderma Fungi

Cadmium (Cd) is one of the heavy metal ions and environmental pollutants that can harm humans and other organisms by eliminating serious toxic effects even at low concentrations. Nowadays, the use of this element in various industries has increased its concentration in the environment. Therefore, it is necessary to find appropriate and practical ways to remove it from the environment. The purpose of this study is to evaluate the efficiency of Trichoderma in the absorption of cadmium ions from an aqueous solution by a central composite design (CCD) to optimize the experimental conditions. Analysis of variance (ANOVA) was performed to study the importance and effectiveness of the model. Design specialist software reviewed four independent variables: pH, mixing rate, contact time, temperature, and initial cadmium concentration. A second-order quadratic model was developed to predict the reactions. An ANOVA of cadmium decay in solutions by Trichoderma shows an F-value of 6655.67 for the quadratic model, which indicates that the model is significant. CCD was able to provide a statistical model for predicting response with high accuracy and reliability. Under optimal conditions, the average cadmium decrease (pH = 6, contact time of 120 minutes, initial concentration of cadmium ions of 25° C and 25 mg/L) is approximately 98.8%.

Trichoderma spp. in growth promotion of Jacaranda mimosifolia D. Don

The low volume of information related to the interaction of Trichoderma fungi with seeds and seedlings represents a limitation to forest production, and it is important to carry out studies focusing on its effect on plant germinability and formation. The aim was to evaluate commercial products based on Trichoderma spp. in promoting growth of Jacaranda mimosifolia. For initial seedling growth assay, seeds were treated with Trichoderma spp. suspension and placed on germinating paper sheets. At 28 days after sowing (DAS) the following evaluations were: percentage germination (PG), root length (RL), shoot length (SL), total length (TL), fresh root mass (FRM), fresh shoot mass (FSM), fresh total mass (FTM), root dry mass (RDM), shoot dry mass (SDM) and total dry mass (BIO). To evaluate the development of Jacaranda mimosifolia plants, the experiment was conducted in a greenhouse, wherein the soil of each pot (10 L) was treated with five strains of the Trichoderma spp. (Trichoderma asperellum URM 5911; T. harzianum ESALQ 1306; T. harzianum IBLF 006 WP; T. harzianum SIMBI T5 and T. harzianum T-22 WG. Then, Jacaranda mimosifolia seeds were sown and the evaluations performed at 120 DAS. The variables were: PG at 120 DAS, shoot height (SH), stem diameter (SD), and Dickson quality index (DQI). The strains SIMBI T5, ESALQ 1306 and T-22 WG stood out in relation to RL; while ESALQ 1306 and SIMBI T5 stood out performed the RL and TL. In greenhouse, SIMBI T5 and ESALQ1306 presented higher values of ALT, CR, DC, MFT. Meanwhile, only the SIMBI T5 strain stood out for MSPA, MSR, BIO and DQI.

Trichoderma Strains and Metabolites Selectively Increase the Production of Volatile Organic Compounds (VOCs) in Olive Trees

Plants emit volatile organic compounds (VOCs) that induce metabolomic, transcriptomic, and behavioral reactions in receiver organisms, including insect pollinators and herbivores. VOCs’ composition and concentration may influence plant-insect or plant-plant interactions and affect soil microbes that may interfere in plant-plant communication. Many Trichoderma fungi act as biocontrol agents of phytopathogens and plant growth promoters. Moreover, they can stimulate plant defense mechanisms against insect pests. This study evaluated VOCs’ emission by olive trees (Olea europaea L.) when selected Trichoderma fungi or metabolites were used as soil treatments. Trichoderma harzianum strains M10, T22, and TH1, T. asperellum strain KV906, T. virens strain GV41, and their secondary metabolites harzianic acid (HA), and 6-pentyl-α-pyrone (6PP) were applied to olive trees. Charcoal cartridges were employed to adsorb olive VOCs, and gas chromatography mass spectrometry (GC-MS) analysis allowed their identification and quantification. A total of 45 volatile compounds were detected, and among these, twenty-five represented environmental pollutants and nineteen compounds were related to olive plant emission. Trichoderma strains and metabolites differentially enhanced VOCs production, affecting three biosynthetic pathways: methylerythritol 1-phosphate (MEP), lipid-signaling, and shikimate pathways. Multivariate analysis models showed a characteristic fingerprint of each plant-fungus/metabolite relationship, reflecting a different emission of VOCs by the treated plants. Specifically, strain M10 and the metabolites 6PP and HA enhanced the monoterpene syntheses by controlling the MEP pathway. Strains GV41, KV906, and the metabolite HA stimulated the hydrocarbon aldehyde formation (nonanal) by regulating the lipid-signaling pathway. Finally, Trichoderma strains GV41, M10, T22, TH1, and the metabolites HA and 6PP improve aromatic syntheses at different steps of the shikimate pathway.

Biosurfactants from Trichoderma Filamentous Fungi—A Preliminary Study

Biosurfactants represent a structurally diverse group of secondary metabolites produced by bacteria, yeasts, and filamentous fungi. Their character is often associated with numerous additional properties. The observation of Trichoderma fungi of various species used as a source of bioinhibitors against pathogenic plants fungi focuses attention to the often quite specific behavior of preparations in contact with, among others, plant leaves, dependent on strain. Thus, an evaluation of the selected strains belonging to the species: T. atroviride, T. citrinoviride,T. reesei and T. harzianum was conducted towards their capability of the extracellular secretion of surfactants, with a simultaneous attempt to pre-determine their chemical nature. Two mineral-organic media were used for this purpose, and the culture fluid was extensively tested using a variety of methods. A decrease in surface tension was observed in culture fluid of each tested strain, especially T. citrinoviride HL and C1. The results strongly depended on medium composition, of which Saunders 1 and MGP 1 were most beneficial. The secreted compounds were further analyzed to pre-determine their chemical nature using IR, GC, and NMR. In the case of most efficient biosurfactant producers, a lipopeptide structure of the surfactants was concluded.

Antimicrobial activity in cultures of endophytic fungi isolated from Talinum triangulare

. Endophytic fungi colonize the interior of plants without causing damage and act in symbiosis with their host. They are also potential sources of compounds with potential applications in industry, agriculture, and medicine, Thus, this study aimed to isolate and identify the endophytic fungi medicinal plant Talinum triangulare and evaluate its potential for the production of antimicrobial substances using the disk diffusion technique and testing in liquid medium front of Staphylococcus aureus ATCC SA 6538, Pseudomonas aeruginosa ATCC PA 0030, and Corynebacterium diphtheria ATCC 27012. Corynebacterium diphtheria was isolated from 3 fungi of the genus Trichoderma and Penicillium, with only the genus Trichoderma fungi showing antimicrobial activity.

ASSESSMENT OF SEAFOOD PROCESSING SLUDGE AFTER COMPOSTING ON GROWTH OF TAGETES PATULA L.

Sludge of seafood processing factories discharged directly into the environment can lead to environmental pollution. Research on the use of seafood processing sludge as compost for agriculture in the Mekong Delta is encouraged. The objectives of this study were (1) to evaluate the chemical composition of seafood processingsludge after 60 days composting and (2) to evaluate the growth of Tagetes patula L planted with composted sludge. The sludge composting experiment was carried out with 3 treatments: sludge + Trichoderma fungi; sludge + chicken manure + Trichoderma fungi; sludge + straw + chicken manure + Trichoderma fungi. The results showed that the treatment of sludge + straw + chicken manure + Trichoderma fungi had a betterquality than the other two treatments. The pH, TC, TN, NH+ 4 , NO- 3 , TP, PO3 4- and heavy metal(Pb, Cd, Cr, Cu, Ni, Zn and Hg) contents of sludge meet the environmental standard of Viet Nam (10TCN526:2002). E. coli and Salmonella were not present at the end of the composting experiment. Tagetes patula L grew and flowered on all 4 treatments: control – composted straw; sludge + Trichoderma fungi; sludge + chicken manure + Trichoderma fungi; sludge + straw + chicken manure + Trichoderma fungi. However,Tagetes patula L grew best on the sludge + Trichoderma fungi experimental condition .

Study on Trichoderma Citrinoviride 31/4 – Antagonistic Activity and Jasmonic Acid

The genus Trichoderma was first identified by the German scientist Persoon in 1974, and there are currently 89 species in the genus. Trichoderma fungi often break down organic compounds in the soil into minerals and plays an important role in soil fertility formation. Trichoderma citrinoviride 31/4 isolated from the soil forms a colony with light yellow-green mycelium on the surface of the PDA medium, with spherical spore, septate hyphae, branched conidophores. Trichoderma citrinoviride 31/4 had antagonistic activity of 66.7% against Cladosporium fulvum, 77.5% against Alternaria alternata, and 59.1% against Fusarium oxysporium after 7 days. Experimental results showed that the progress of tomato alternariosis treated with Trichoderma citrinoviride 31/4 was neutralized from the 7th day, and the biological activity was averagely 74% on the 21st day. Trichoderma citrinoviride 31/4 contains 0.0135 mg / kg of jasmonic acid in plants treated with 109 cell / ml and 0.0076 mg/kg in plants treated with 108 cell / ml.