Harzianum Strain Research Articles

Effects of Below-Ground Microbial Biostimulant Trichoderma harzianum on Diseases, Insect Community, and Plant Performance in Cucurbita pepo L. under Open Field Conditions.

Agrochemicals are generally used in agriculture to maximize yields and product quality, but their overuse can cause environmental pollution and human health problems. To reduce the off-farm input of chemicals, numerous biostimulant products based on beneficial symbiont plant fungi are receiving a great deal of attention. The evolution of plant diseases and the performance of insects are influenced by plant chemical defences, both of which are, in turn, influenced by below-ground symbionts. Direct and indirect plant defences mediated by belowground symbionts against plant diseases and insect herbivores were demonstrated in greenhouses experiments. However, little attention has been paid to the use of Trichoderma under open field conditions, and no data are available for zucchini (Cucurbita pepo L.) plants in the field. To determine the effects of a commercial Trichoderma harzianum strain T22 on plant viruses, powdery mildew, the arthropod community, and on the agronomic performance associated with zucchini plants, an experiment was conducted in 2022 under open field conditions in South Italy. Our results indicate that T. harzianum T22 makes zucchini plants more attractive to aphids and to Hymenoptera parasitoid but failed to control zucchini pathogens. The complex plant-disease-arthropod-microorganism interactions that occurred in the field during the entire plant cycle are discussed to enrich our current information on the possibilities of using these microorganisms as a green alternative in agriculture.

Evaluation of Sclerotinia sclerotiorum MTCC 8785 as a biological agent for the synthesis of silver nanoparticles and assessment of their antifungal potential against Trichoderma harzianum MTCC 801

IntroductionOwing to loads of industrial development and advancements, there is an unmet need for green-ecosystem support as well as safe technologies. For cost-cutting and eco-friendly applications, biosynthetic pathways for nanoparticle synthesis from microbes like bacteria, and fungi have attracted the global attention of researchers. MethodsIn the present research work, silver nanoparticles (AgNPs) from fungus (mycogenic) were extracellularly synthesized with cell-free filtrates of fungal phytopathogen Sclerotinia sclerotiorum MTCC 8785 harvested from broth culture in Potato dextrose broth (CFF-PDB) and Amylase production media (CFF-AMP). The synthesis was carried out at pH 7, 28 °C under dark conditions. The synthesized AgNPs were characterized using UV spectrophotometer and transmission electron microscopy (TEM). Furthermore, the antifungal efficacy of AgNPs was evaluated against the Trichoderma harzianum MTCC 801 strain by radial inhibition assay. ResultsPrimarily, the process of biosynthesis was inferred by the characteristic change of color and spectral peak at 420 nm recorded with UV spectrophotometer further approved the nano silver production in CFF-AMP which approves the role of amylases in reduction mediated capping process. TEM analysis revealed that the AgNPs synthesized using S. sclerotiorum MTCC 8785 grown in PDB were spherical with variable size ranges from 10 to 50 nm in diameter whereas, the AgNPs synthesized using S. sclerotiorum MTCC 8785 grown in APM were in the size ranges from 40 to 50 nm. ConclusionsThis is the first investigatory concern where nano-silver from fungal phytopathogen S. sclerotiorum MTCC 8785 has been prospected as new age antifungal alternatives against evolving threats from T. harzianum strain.

Microplastic-Induced Oxidative Stress in Metolachlor-Degrading Filamentous Fungus Trichoderma harzianum.

While there has been intensive research on the influence of microplastics (MPs) on aquatic organisms and humans, their effect on microorganisms is relatively little-known. The present study describes the response of the Trichoderma harzianum strain to low-density polyethylene (LDPE) microparticles. MPs, either separately or with metolachlor (MET), were added to the cultures. Initially, MP was not found to have a negative effect on fungal growth and MET degradation. After 72 h of cultivation, the content of fungal biomass in samples with MPs was almost three times higher than that in the cultures without MPs. Additionally, a 75% degradation of the initial MET was observed. However, due to the qualitative and quantitative changes in individual classes of phospholipids, cell membrane permeability was increased. Additionally, MPs induced the overproduction of reactive oxygen species. The activity of superoxide dismutase and catalase was also increased in response to MPs. Despite these defense mechanisms, there was enhanced lipid peroxidation in the cultures containing the LDPE microparticles. The results of the study may fill the knowledge gap on the influence of MPs on filamentous fungi. The findings will be helpful in future research on the biodegradation of contaminants coexisting with MPs in soil.

Optimization, purification, and characterization of xylanase production by a newly isolated Trichoderma harzianum strain by a two-step statistical experimental design strategy

Xylanases are hydrolytic enzymes with a wide range of applications in several industries such as biofuels, paper and pulp, food, and feed. The objective of this study was to optimize the culture conditions and medium components for maximal xylanase production from a newly isolated Trichoderma harzianum strain using the Plackett–Burman Design (PBD) and Box Behnken Design (BBD) experimental strategies. Xylanase production was enhanced 4.16-fold to 153.80 U/ml by BBD compared to a preliminary one-factor-at-a-time (OFAT) activity of 37.01 U/ml and 2.24-fold compared to the PBD (68.70 U/ml). The optimal conditions for xylanase production were: 6 days of fermentation, incubation temperature of 70 °C, pH 5.0, agitation of 160 rpm, and 1.2% wheat bran and ammonium sulphate. The experimental design effectively provided conditions for the production of an acidic-thermostable enzyme with exciting potential for application in animal feed improvement. The acidic-thermostable xylanase was purified from the submerged culture and SDS-PAGE analysis revealed a molecular weight of 72 kDa. This protein had maximum xylanolytic activity at pH 6.0 and 65 °C and was stable for 4 h retaining > 70% activity and exhibited substrate specificity for beechwood xylan with a Km of 5.56 mg/ml and Vmax of 1052.63 µmol/min/mg. Enzyme activity was enhanced by Fe2+, Mg2+, and Zn2+. There was an absence of strong inhibitors of xylanase activity. Overall, these characteristics indicate the potential for at least two industrial applications.

Characterization and antagonistic potentials of selected rhizosphere Trichoderma species against some Fusarium species.

Trichoderma fungi have been proved as efficient bioagents with great antifungal properties while many species in the plant’s rhizospheres have been characterized as plant growth-promoting agents. However, many rhizosphere Trichoderma are yet to be fully explored for plant disease management. In this study, Trichoderma species were isolated from the rhizosphere of maize, banana, and cassava, and their biocontrol potentials were screened against some Fusarium species from oak leaves (F2B and F3) and laboratory cultures (Fus 296 and Fus 294). The isolated rhizosphere Trichoderma were identified as Trichoderma virens 1 (TCIV), T. virens 2 (TCVII), T. virens 3 (TMSI), T. hazianum strain 1 (TCVI), T. harzianum strain 2 (TCVIII), T. erinaceum (TMZI), and T. koningiopsis (TMZII). The dual culture experiment recorded the highest percentage inhibition in TMZII against OakF2B (31.17%), TCVIII against Fus 294 (45.18%), TMZI against Fus 296 (47.37%), while TCIV was most effective against Oak F3 (44.15%). Among the Trichoderma culture filtrates evaluated, TCIV showed the highest percentage inhibition against Oak F3 (52.39%), Oak F2B (48.54%), Fus 294 (46.65%), and Fus 296 (44.48%). All the Trichoderma isolates demonstrated expressed varying levels of antagonism against the Fusarium pathogens in vitro.

Evaluation of Selected Biological and Chemical Treatments against Soil-Borne Diseases of Ginger in High Tunnel Production

With its multifaceted health benefits, ginger is one of the commonly consumed dietary condiments with continued demand worldwide leading to more importation into countries such as the U.S. The rhizome of ginger, the seed-piece but also the edible portion, is highly vulnerable to pathogen infections causing seed-piece and soil-borne diseases (SSDs). Laboratory and high tunnel (HT) studies were conducted between 2018 and 2020 to evaluate the effect of soil and transplant drenches of selected biocontrol agents (BCAs) and chemicals. In vitro dual-culture tests revealed that the Trichoderma harzianum strain T-22 (Th-22) grew significantly faster than Fusarium oxysporum f.sp. zingiberi (Foz), the fungus causing yellows and rhizome rot in ginger. Th-22 grew more than three times faster than Foz within 3 days and engulfed the pathogen within 7 days when incubated at 30 °C. The bioproducts (RootShield® Plus, LifeGard®), an insecticide/nematicide (Vydate®) and disinfectant (10% Clorox) tested against Foz and any pre-existing pathogens in a HT significantly reduced severity of yellowing and rhizome rot when compared with the non-treated control. Yield was significantly higher for RootShield® Plus compared to the control in one of the trials. Spatially, declining ginger growth but an increased incidence of SSDs were observed as one walked from the door towards the back of the HT. Phospho-lipid fatty acid analysis showed better microbial activity on soils that received drenches of BCAs than on soils sampled pre-treatment.

Identification of a Novel Lipase with AHSMG Pentapeptide in Hypocreales and Glomerellales Filamentous Fungi.

Lipases are enzymes that hydrolyze triglycerides to fatty acids and glycerol. A typical element in lipases is a conserved motif of five amino acids (the pentapeptide), most commonly G-X-S-X-G. Lipases with the pentapeptide A-X-S-X-G are present in species of Bacillus, Paucimonas lemoignei, and the yeast Trichosporon asahii; they are usually thermotolerant and solvent resistant. Recently, while searching for true lipases in the Trichoderma harzianum genome, one lipase containing the pentapeptide AHSMG was identified. In this study, we cloned from T. harzianum strain B13-1 the lipase ID135964, renamed here as ThaL, which is 97.65% identical with the reference. We found that ThaL is a lid-containing true lipase of cluster III that belongs to a large family comprising highly conserved proteins in filamentous fungi in the orders Hypocreales and Glomerellales, in which predominantly pathogenic fungi are found. ThaL was expressed in conidia, as well as in T. harzianum mycelium, where it was cultured in liquid minimal medium. These results—together with the amino acid composition, absence of a signal peptide, mitochondrial sorting prediction, disordered regions in the protein, and lineage-specific phylogenetic distribution of its homologs—suggest that ThaL is a non-canonical effector. In summary, AHSMG-lipase is a novel lipase family in filamentous fungi, and is probably involved in pathogenicity.

Promotion of Plant Growth in Arid Zones by Selected Trichoderma spp. Strains with Adaptation Plasticity to Alkaline pH.

Simple SummaryProductivity in agriculture is affected by nutrient-deficit soil, a phenomenon caused by anthropogenic activities or by geographical location, such as in arid zones. The pH affects the availability of chemical compounds, which is why it is an elementary parameter for the survival of organisms. These conditions on the soil cause the inhibition of microorganism growth. Trichoderma are filamentous fungi located in a great diversity of ecosystems. They are commonly associated with plants and carry out fundamental activities in the development, biological control, and nutrition of plants. The study of areas with extreme conditions represents a valuable source of new strains with adaptations to environmental demands; locating sites where there are fungi with tolerance, evolution events, and adaptations to biotic and abiotic conditions provides evidence that there are microorganisms with the potential to improve soils and generate a positive effect on vegetable crops.Trichoderma species are filamentous fungi that support plant health and confer improved growth, disease resistance, and abiotic stress tolerance. The objective of this study is to describe the physiological characteristics of the abundance and structure of Trichoderma model strains from arid zones and evaluate and describe their possible adaptation and modulation in alkaline pH. The presence of biotic factors such as phytopathogens forces farmers to take more actions such as using pesticides. In addition, factors such as the lack of water worldwide lead to losses in agricultural production. Therefore, the search for biocontrol microorganisms that support drought opens the door to the search for variations in the molecular mechanisms involved in these phenomena. In our case, we isolated 11 tested Trichoderma fungal strains from samples collected both from the rhizosphere and roots from two endemic plants. We probed their molecular markers to obtain their identity and assessed their resistance to alkaline conditions, as well as their response to mycoparasitism, plant growth promotion, and drought stress. The findings were worthy of being analyzed in depth. Three fungal taxa/species were grouped by phylogenetic/phenotypic characteristics; three T. harzianum strains showed outstanding capabilities to adapt to alkalinity stress. They also showed antagonistic activity against three phytopathogenic fungi. Additionally, we provided evidence of significant growth promotion in Sorghum bicolor seedlings under endemic agriculture conditions and a reduction in drought damage with Trichoderma infection. Finally, beneficial fungi adapted to specific ambient niches use various molecular mechanisms to survive and modulate their metabolism.

Effective biofertilizer Trichoderma spp. isolates with enzymatic activity and metabolites enhancing plant growth.

Trichoderma species have been widely recognized as biofertilizer fungi for their ability to produce phytohormones and enhance plant growth. In our current study, fifteen strains of Trichoderma spp. (T1-T15) were screened for their capacity to produce phytohormones and metabolites eliciting plant growth. The stains were previously isolated from olive rhizosphere soil in northern Algeria. Plant growth promoting (PGP) potential of Trichoderma spp. was evaluated in vitro through the production of phosphatases, siderophores, hydrogen cyanide (HCN), and ammonia (NH3). Besides, plant growth phytohormones such as gibberellic acid and indole-3-acetic acid (IAA) were assessed quantitatively by a colorimetric assay. Results showed an effective potential of Trichoderma spp. in plant growth-promoting biomolecule production. Importantly, qualitative estimation of phosphate solubilization indicates that T10 gave the highest phosphate solubilization on medium Pikovskaya's with a solubilization index (SI) of 3, whereas, the high capacity nitrogen-fixing was related to T8. On the other hand, quantitative analysis of indole-3-acetic acid and gibberellic acid revealed a production varying between (1.30μgmL-1 to 21.15μgmL-1) and (0.53μgmL-1 to 7.87μgmL-1), respectively; the highest amount of both phytohormones was obtained by T11 isolate. Indeed, an analysis of ethyl acetate extracts of T11 isolate by high-performance liquid chromatography (HPLC) revealed a high amount (71.19mg L-1) of IAA. Overall, the results showed clearly that isolate T11 has promising plant growth-promoting properties. Hence, this native Trichoderma isolate (T11) identified as Trichoderma harzianum strain (OL587563) could be used later as biofertilizer for sustainable olive crop agriculture.

The Newly Identified Trichoderma harzianum Partitivirus (ThPV2) Does Not Diminish Spore Production and Biocontrol Activity of Its Host.

A new partititvirus isolated from a Trichoderma harzianum strain (T673), collected in China, was characterized and annotated as Trichoderma harzianum partitivirus 2 (ThPV2). The genome of ThPV2 consists of a 1693 bp dsRNA1 encoding a putative RNA-dependent RNA polymerase (RdRp) and a 1458 bp dsRNA2 encoding a hypothetical protein. In comparative studies employing the ThPV2-infected strain (T673) and a strain cured by ribavirin treatment (virus-free strain T673-F), we investigated biological effects of ThPV2 infection. While the growth rate of the virus-infected fungus differed little from that of the cured variant, higher mycelial density, conidiospore, and chlamydospore production were observed in the virus-infected strain T673. Furthermore, both the ThPV2-infected and the cured strain showed growth- and development-promoting activities in cucumber plants. In vitro confrontation tests showed that strains T673 and T673-F inhibited several important fungal pathogens and an oomycete pathogen in a comparable manner. Interestingly, in experiments with cucumber seeds inoculated with Fusarium oxysporum f. sp. cucumerinum, the ThPV2-infected strain T673 showed moderately but statistically significantly improved biocontrol activity when compared with strain T673-F. Our data broaden the spectrum of known mycoviruses and provide relevant information for the development of mycoviruses for agronomic applications.

SOIL FUNGI PROMOTE VIGOR IN SEEDS FROM BRAZILIAN DRY SEASONAL FOREST

The Brazilian Dry Seasonal Forest (Caatinga Biome) is poorly studied about possible interactions between seeds, seedlings, and Trichoderma harzianum strains to promote vegetal vigor in seedlings. So, this research aims to study the T. harzianum strain promotion of vigor in different species from Caatinga Biome in nursery. For assays, we used: Aspidosperma pyrifolium, Cnidoscolus quercifolius, Handroanthus impetiginosus, Pseudobombax marginatum , and Tabebuia aurea species and the T. harzianum IBLF 006 based-product-inoculant. We tested these assays in nursery conditions. T. harzianum solution (0.5% v/V) was used in the nursery assay (applied over soil after the sowing). For this research, we evaluated variables of vigor and germination and there was a control treatment (non-inoculated). About nursery assay results, there was a positive interaction for all species between seeds and seedlings and T. harzianum , except for T. aurea and C. quercifolius . For all species tested in this research, we suggest that other seed or soil treatments can be tested in environmental Caatinga Biome conditions to expand this knowledge about the interaction between Trichoderma harzianum and seedlings and seeds from Caatinga biome.

Chitosan and Trichoderma harzianum a new Challenge for managing Fusarium crown and root rot in asparagus plant

Abstract Fusarium oxysporum f. sp. asparagi is one of the main problems associated with the roots of asparagus plants and inflicting serious losses worldwide. A novel and eco-friendly strategy to reduce pathogen resistance and management of the Fusarium crown and root rot is using chitosan and Trichoderma harzianum as a sustainable treatment approach to improve both disease resistance and yields, while also effectively managing the asparagus product. In this study, the effect of chitosan and Trichoderma harzianum on growth promotion and control of Fusarium crown and root rot in asparagus plants was investigated. diseased plants from the main production areas of Iran were surveyed. The in vitro antifungal properties of chitosan solutions (concentrations of 5, 10, 15 and 20 mg/mL) and T. harzianum strain were evaluated by the dual culture method. T. harzianum and chitosan solution (20 mg/mL) gave the largest inhibition zone against F. oxysporum and were selected for further studies in the greenhouse. Chitosan (20 mg/mL) and T. harzianum were applied as seed treatments and they significantly reduced disease incidence by 92% and 73% respectively, compared to the control.

Interference of bio-control Trichoderma to enhance physical and physiological strength of sugarcane during Pokkah boeng infection.

Tremendous benefits have been derived from the use of fungicides but excessive use of chemical fungicides not only posing threat to human and animal life but also contaminates the prevailing environment. Damage by pathogenic fungi alone causes significant damage to crops like maize, rice, wheat, soybeans, and potatoes. Therefore, it becomes imperative that these diseases are checked and controlled, for which chemical pesticides are being sprayed on plants extensively. Considering the devastating damage and toxicity, the global focus has taken a drift from synthetic chemicals to nature-friendly biological control agents. The present study focuses on the use of biological control agents particularly Trichoderma in sugarcane during Pokkah boeng infection. In the present experiment, twenty promising Trichoderma strains were evaluated for plant growth promotion, lytic enzymes, and physiological and biocontrol activity. Out of the twenty, four potential Trichoderma strains were assessed in the pot experiment viz. T. harzianum strain T28, T41 and T49 and T. aureoviride strain T38. The T. harzianum (T28) showed efficient plant growth-promoting traits as it produced IAA (20.67µg/ml), phosphorus solubilization (18.57µg/ml), and cell wall degrading enzymes such as chitinase (24.98µg/ml) and β-glucanase (29.98µg/ml). The interference of biocontrol agent T. harzianum (T28) controlled the disease by 73.55%. Apart from this, the inoculation of Trichoderma (T28) enhanced growth attributes including germination percentage (26.61%), mean tiller number (8.28 tiller/pot), individual cane length (241.5cm), single cane weight (1.13kg) and the number of milleable canes (6.00 cane/pot). Improvements in physiological activities at different growth stages of the sugarcane crop were observed based on the photosynthetically active radiation (PAR) on the leaf surface, transpiration rate, stomatal conductance, and photosynthetic rate. Further, improvement in juice quality parameters was also observed as it recorded the highest 0brix, sucrose, and commercial cane sugar by 21.26%, 19.28%, and 13.50%, respectively, by applying T. harzianum strain T28. Thus, results proved that T. harzianum strain T28 may be an effective eco-friendly biocontrol tool for managing Pokkah boeng disease in sugarcane. This is the first report of the biocontrol potential of Trichoderma spp. against Fusarium proliferatum causing Pokkah boeng disease in sugarcane.

Effects of Trichoderma harzianum Strain T22 on the Arthropod Community Associated with Tomato Plants and on the Crop Performance in an Experimental Field.

Simple SummaryThere is currently a global research interest in reducing off-farm input of chemical pesticides and fertilizers by using green alternative practices. Fungi belonging to the genus Trichoderma colonize plant roots and activate systemic plant defenses against the attack of pests and pathogens. Trichoderma spp. have positive impacts on the environment and guarantee food security, which, in turn, offer important economic benefits in agriculture. The purpose of the present study was to investigate the effects of the inoculation of a commercial Trichoderma strain on the arthropod community, downy mildew, and the agronomic performance of tomato plants in an experimental field. Our results showed that inoculation with Trichoderma positively influenced tomato fruit yields and could reduce the abundance of specific pests under field conditions.Fungi belonging to the genus Trichoderma have received much attention in recent years due to their beneficial effects on crop health and their use as pest control agents. Trichoderma activates direct plant defenses against phytophagous arthropods and reinforces indirect plant defense through the attraction of predators. Although the plant defenses against insect herbivores were demonstrated in laboratory experiments, little attention has been paid to the use of Trichoderma spp. in open field conditions. In the present study, we investigated the effects of the inoculation of the commercial Trichoderma harzianum strain T22 on the arthropod community associated with tomato plants and on the crop performance in an experimental field located in South Italy. Our results showed that inoculation with T. harzianum could alter the arthropod community and reduce the abundance of specific pests under field conditions with respect to the sampling period. The present study also confirmed the beneficial effect of T. harzianum against plant pathogens and on tomato fruit. The complex tomato–arthropod–microorganism interactions that occurred in the field are discussed to enrich our current information on the possibilities of using Trichoderma as a green alternative agent in agriculture.

Novel culture chamber to evaluate in vitro plant-microbe volatile interactions: Effects of Trichoderma harzianum volatiles on wheat plantlets

The field of plant-microbe interactions mediated by Biogenic Volatile Organic Compounds (BVOCs) still faces several limitations due to the lack of reliable equipment. We present a novel device designed to evaluate in vitro plant-microbe volatile interactions, the plant-microbe VOC Chamber. It was tested by evaluating the effects exerted on wheat development by volatiles from three Trichoderma harzianum strains, a wild type and two genetically modified strains; one expressing the tri5 gene, which leads to the synthesis and emission of the volatile trichodiene, and the other by silencing the erg1 gene, impairing ergosterol production. The wild type and the erg1-silenced strain enhanced fresh weight and length of the aerial part, but reduced root dry weight. Interestingly, no differences were found between them. Conversely, the tri5-transformant strain reduced root and aerial growth compared to the control and the other strains. No differences were observed regarding chlorophyll fluorescence quantum yield and leaf chlorophyll content, suggesting that the released BVOCs do not interfere with photosynthesis. The plant-microbe VOC Chamber proved to be a simple and reliable method to evaluate the in vitro effects of microbial BVOCs on plant development, perfect for the screening of microorganisms with interesting volatile traits.

Volatile-mediated interactions between Trichoderma harzianum and Acanthoscelides obtectus: A novel in vitro methodology to evaluate the impact of microbial volatile compounds on dry grain storage pests

Biological interactions mediated by Biogenic Volatile Organic Compounds (BVOCs) is a well-established field that has been researched for decades. Although extensive focus is currently given to the control of insect pests using natural molecules, the study of volatile interactions between microorganisms and insects has been largely neglected and has only begun to attract more attention in recent years. In this work, we developed a novel protocol to assess the effects of microbial BVOCs directly produced by growing microbial strains on dry grain insect pests and the seed damage they cause, using VOC Chambers to evaluate both sealed and unsealed conditions. Four Trichoderma harzianum strains were tested against Acanthoscelides obtectus, a wild type and three of its transformants. These had been previously obtained by introducing the tri5 gene and thus overproducing the volatile trichodiene, or by silencing the erg1 gene, which encodes for a squalene epoxidase, therefore reducing ergosterol levels and increasing squalene ones in the fungus. Results demonstrated that ventilation plays a key role in these interactions. All fungal strains significantly increased adult mortality in sealed conditions, while this effect was barely noticeable in unsealed ones. Nevertheless, subsequent insect emergence from bean seeds and bean damage were still significantly reduced in both conditions. The erg1 silenced strains caused significantly higher levels of adult mortality than the rest in sealed conditions and lower insect emergence in both sealed and unsealed ones. Bean damage produced by insects was lower also when exposed to BVOCs from these strains in sealed conditions. Conversely, trichodiene overproduction did not show enhanced toxicity or significant reduction of insect emergence and bean damage in the tested conditions. Therefore, T. harzianum BVOCs, especially those from erg1 silenced strains, should be further researched for their potential use in the biological control of A. obtectus infestation in dry grain storing facilities. VOC Chambers have shown themselves to be a reliable method in the screening of in vitro volatile mediated interactions between growing microbial strains and insect pests.

Network Analysis Reveals Different Cellulose Degradation Strategies Across Trichoderma harzianum Strains Associated With XYR1 and CRE1.

Trichoderma harzianum, whose gene expression is tightly controlled by the transcription factors (TFs) XYR1 and CRE1, is a potential candidate for hydrolytic enzyme production. Here, we performed a network analysis of T. harzianum IOC-3844 and T. harzianum CBMAI-0179 to explore how the regulation of these TFs varies between these strains. In addition, we explored the evolutionary relationships of XYR1 and CRE1 protein sequences among Trichoderma spp. The results of the T. harzianum strains were compared with those of Trichoderma atroviride CBMAI-0020, a mycoparasitic species. Although transcripts encoding carbohydrate-active enzymes (CAZymes), TFs, transporters, and proteins with unknown functions were coexpressed with cre1 or xyr1, other proteins indirectly related to cellulose degradation were identified. The enriched GO terms describing the transcripts of these groups differed across all strains, and several metabolic pathways with high similarity between both regulators but strain-specific differences were identified. In addition, the CRE1 and XYR1 subnetworks presented different topology profiles in each strain, likely indicating differences in the influences of these regulators according to the fungi. The hubs of the cre1 and xyr1 groups included transcripts not yet characterized or described as being related to cellulose degradation. The first-neighbor analyses confirmed the results of the profile of the coexpressed transcripts in cre1 and xyr1. The analyses of the shortest paths revealed that CAZymes upregulated under cellulose degradation conditions are most closely related to both regulators, and new targets between such signaling pathways were discovered. Although the evaluated T. harzianum strains are phylogenetically close and their amino acid sequences related to XYR1 and CRE1 are very similar, the set of transcripts related to xyr1 and cre1 differed, suggesting that each T. harzianum strain used a specific regulation strategy for cellulose degradation. More interestingly, our findings may suggest that XYR1 and CRE1 indirectly regulate genes encoding proteins related to cellulose degradation in the evaluated T. harzianum strains. An improved understanding of the basic biology of fungi during the cellulose degradation process can contribute to the use of their enzymes in several biotechnological applications and pave the way for further studies on the differences across strains of the same species.

Mitochondrial Genome Resource of a Grapevine Strain of Trichoderma harzianum, a Potential Biological Control Agent for Fungal Canker Diseases

Trichoderma spp. are commonly used as bioremediation agents, biological controls, and for making biofuels. Herein, a Trichoderma harzianum strain PAR3 was isolated from grapevine roots in central California, USA. As part of a larger whole genome sequencing effort, the mitochondrial genome (mitogenome) sequence was obtained for the PAR3 strain. The mitogenome is 27,631 bp containing genes of 14 core mitochondrial proteins, 25 tRNA, and two rRNAs and a GC% content of 27.55%. BLAST search using the PAR3 mitogenome as query against GenBank sequence database showed mitogenome MUT3171 (29,791 bp) of Trichoderma lixii was the most similar (Query Coverage = 99%; Percentage Identity=100.00%) with two major deletions, 1,339 bp and 821 bp. The PAR3 mitogenome sequence will provide a useful reference for comparing different Trichoderma strains from US and around the world.

Trichoderma harzianum Suşlarının Domates Fide Kalitesine Etkileri

This study was conducted to determine the effects of Trichoderma harzianum on seedling growth and quality as two consecutive experiments during the spring months of 2018. In the first experiment, four different T. harzianum strains and a commercial preparate were used by adding into seed sowing substrate and compared with control group which had no treatment. The most promising strain (strain2), was used with and without foliar fertilizer (20:20:20) and foliar fertilizer itself was considered as control. Emergence period and rate were determined to observe the effects of treatments of germination of seeds. Regarding the seedling growth and quality, seedling length, root length, hypocotyl diameter, leaf thickness, fresh and dry weights of root and shoots, dry matter content, color, chlorophyll index, leaf macro and micro plant nutrient contents and seedling quality index were determined at the planting stage. Data obtained from the first experiment showed that the effects of T. harzianum strains on seedling morphology, physiology and nutrient content were different. Among the tested strains, strain2 showed better performance on seedling length, root and shoot dry matter contents, total fresh weight, chlorophyll, a color value and P, Ca, Mn, Cu and Zn contents of leaves and improved seedling quality. The second experiment result showed that the foliar fertilizer application increased the efficiency of T. harzianum strain2. T. harzianum strain2 without foliar fertilizer remained below the control treament in all measured parameters. When all the data were evaluated together, it was concluded that T. harzianum could be used to increase seedling quality due to its positive effects on seedling biomass, plant nutrition uptake and quality index. Moreover, it can be used in organic seedling production as alternative biostimulant.

Kinetic Study of Fungal Growth of Several Tanninolytic Strains Using Coffee Pulp Procyanidins

Procyanidins are bioactive molecules with industrial and pharmaceutical relevance, they are present in recalcitrant agro-industrial wastes that are difficult to degrade. In this study, we evaluated the potential consumption of procyanidins from Aspergillus niger and Trichoderma harzianum strains in submerged fermentations. For this purpose, a culture medium containing salts, glucose, and procyanidins was formulated, where procyanidins were added to the medium after the near-total consumption of glucose. The submerged cultures were carried out in amber flasks at 30 °C and 120 rpm. The addition of procyanidins to the culture medium increased the formation of micellar biomass for all the strains used. The use of glucose affected the growth of A. niger GH1 and A. niger HS1, however, in these assays, a total consumption of procyanidins was obtained. These results show that the consumption of procyanidins by fungal strains in submerged fermentations was influenced by the pH, the use of glucose as the first source of carbon, and the delayed addition of procyanidins to the medium. The study showed that A. niger and T. harzianum strains can be used as a natural strategy for the consumption or removal of procyanidins present in recalcitrant residues of risk to the environment and human health.