Harzianic Acid Research Articles

Lipids, proteins and extracellular metabolites of Trichoderma harzianum modifications caused by 2,4-dichlorophenoxyacetic acid as a plant growth stimulator

Strains of Trichoderma harzianum are well-known producers of bioactive secondary metabolites and have a beneficial effect on plants. However, to the best of our knowledge, the effect of the commonly used pesticides on the activity of this fungus is not yet investigated. Therefore, in the present study, the effect of the herbicide 2,4-dichlorophenoxyacetic acid (2,4-D) on the lipidome and selected extracellular compounds synthesized by T. harzianum IM 0961 was examined. It was observed that the herbicide 2,4-D caused changes in the lipid composition of the mycelium and that the herbicide exhibited lipophilic properties. In addition, the herbicide disturbed the phosphatidylcholine (PC)/phosphatidylethanolamine (PE) ratio and increased membrane permeability. The higher amount of cardiolipin CL 72:7 and the lower amount of CL 72:8 could have been associated with a decreased ratio of 18:2 and 18:1 fatty acids in the herbicide-treated samples. Moreover, in the presence of 2,4-D, an increased lipid peroxidation (twofold), as well as a higher content of oxylipin (9-HODE and 13-HODE) and phosphatidic acid (PA), was noted, confirming that 2,4-D induced lipid peroxidation in the mycelium. The herbicide also exerted its toxic effect on the production of 14-aminoacid peptaibols and two compounds, harzianic acid and t22-azaphilone, exhibiting antibiotic and plant growth-promoting activity. During proteomic analysis, the synthesis of some proteins, such as calcineurin-like phosphoesterase metallophosphatases (MPPs), which modulate the properties of cell walls, was found to be inhibited by the herbicide. These presented findings may be of significant value in understanding the effect of 2,4-D on the activity of T. harzianum.

NOVEL ROLE OF 6-N-PENTYL-6H-PYRAN-2-ONE PRODUCED BY Trichoderma harzianum IN HYDROPONIC SYSTEM

Secondary metabolites play a pivotal role in the antagonistic activities of some biocontrol species of Trichoderma sp. T. harzianum used previously as biological control agent against different pathogens. In this work, the effect of F. oxysporum f. sp. gladioli on the major secondary metabolites secreted by biocontrol strain of T. harzianum in Potato Dextrose Broth (PDB) cultures were investigated and quantified; followed by investigating the effect of the previous microorganisms on T. harzianumsecondary metabolites secreted in Gladiolus grandiflorus corms tissues under controlled conditions. Thin Layer Chromatography (TLC), Liquid chromatography Mass spectroscopy (LC/MS), and Nuclear Magnetic Resonance (NMR) techniques were used in this study to determine the major secondary metabolites. This is the first report recording the isolation, characterization and quantification of 6-n-pentyl-6H-pyran-2-one (6PP) and harzianic acid (HA) from the treated corms with T. harzianum. The secreted amounts from both metabolites were increased in the pre treated corms with T. harzianum followed by infection with F. oxysporum f. sp. gladioli. Results provided better understandings of the interaction mechanism between T. harzianum, F. oxysporum f. sp. gladioli which could be used in the future in different gene expression studies and will help in using them as bio fertilizers in biocontrol field.

Application of Trichoderma Strains and Metabolites Enhances Soybean Productivity and Nutrient Content.

Trichoderma fungi are effectively marketed worldwide as biocontrol agents and plant biostimulants on numerous crops due to their demonstrated effects in direct antagonism against fungal pathogens and plant growth promotion. Here, we examined the effects of single and combined applications of Trichoderma strains and their bioactive metabolites (BAMs) harzianic acid (HA), 6-pentyl-α-pyrone (6PP), and hydrophobin1 (HYTLO1) on the growth, yield, and nutrient uptake of soybean plants. Significant promotion of plant growth (up to 39%), as well as an increase in mineral content, was achieved with BAMs, used alone or combined with T. harzianum. Interestingly, the treatments also increased the level of fatty acids (oleic, linolenic, 11-eicosenoic, and stearic). This work demonstrates the usefulness of natural compound and microbe combinations to enhance oilseed productivity, and reports for the first time the ability of Trichoderma and/or its BAMs to increase the lipid content in harvested seeds.

Antifungal potential of native Trichoderma isolates against Pythium aphanidermatum causing Chilli damping-off

Efficacy of 23 Trichoderma isolates was tested for their ability to reduce the growth of Pythium aphanidermatum causing damping-off of chilli. Studies revealed that locally isolated Trichoderma harzianum showed the highest inhibition (98.1%) followed by T. asperellum (88.8%), T. hamatum (86.6%), T. longibrachiatum (85.2%) and T. koningiopsis (84.3%) and other Trichoderma spp. against the growth of P. aphanidermatum. Highly potential five isolates of Trichoderma were selected for pot culture evaluation for germination %, pre and post-emergence damping-off and growth parameter of chilli seedlings. Among five Trichoderma isolates, seed treatment with T. harzianum at 2×108 CFU ml−1 recorded highest germination (93.7%), shoot length (10.03 cm) and root length (05.65 cm) and was also better in reducing the pre and post emergence damping-off (84.3% and 85.0%, respectively) followed by T. asperellum and rest of the treatments. The antimicrobial volatile compounds isolated from T. harzianum were 6 pentyl-α-Pyrone, Heneicosane, Harzianic acid and 1, 2 Benzene dicarboxylic acid.

Modulation of Tomato Response to Rhizoctonia solani by Trichoderma harzianum and Its Secondary Metabolite Harzianic Acid.

The present study investigated the transcriptomic and metabolomic changes elicited in tomato plants (Solanum lycopersicum cv. Micro-Tom) following treatments with the biocontrol agent Trichoderma harzianum strain M10 or its purified secondary metabolite harzianic acid (HA), in the presence or the absence of the soil-borne pathogen Rhizoctonia solani. Transcriptomic analysis allowed the identification of differentially expressed genes (DEGs) that play a pivotal role in resistance to biotic stress. Overall, the results support the ability of T. harzianum M10 to activate defense responses in infected tomato plants. An induction of hormone-mediated signaling was observed, as shown by the up-regulation of genes involved in the ethylene and jasmonate (ET/JA) and salicylic acid (SA)-mediated signaling pathways. Further, the protective action of T. harzianum on the host was revealed by the over-expression of genes able to detoxify cells from reactive oxygen species (ROS). On the other hand, HA treatment also stimulated tomato response to the pathogen by inducing the expression of several genes involved in defense response (including protease inhibitors, resistance proteins like CC-NBS-LRR) and hormone interplay. The accumulation of steroidal glycoalkaloids in the plant after treatments with either T. harzianum or HA, as determined by metabolomic analysis, confirmed the complexity of the plant response to beneficial microbes, demonstrating that these microorganisms are also capable of activating the chemical defenses.

Trichoderma and its secondary metabolites improve yield and quality of grapes

Trichoderma is one of the most studied and applied fungal biocontrol agents. The benefits of these microorganisms to the plant include: suppression of pathogens, growth promotion, enhanced nutrient availability and induction of resistance. The biological activity is related to the variety of metabolites that they produce. These metabolites have been found to directly inhibit the pathogens, increase disease resistance and enhance plant growth.In this study, we have examined the effect of two Trichoderma strains and their secondary metabolites on Vitis vinifera in terms of induction of disease resistance, plant growth promotion and increase of polyphenols or antioxidant activity in the grapes. Applications of T. harzianum M10 or T. atroviride P1, as well as their respective major secondary metabolites, harzianic acid (HA) and 6-pentyl-α-pyrone (6PP), have been conducted in greenhouse by foliar spray or drenching. The treatments suppressed the development of powdery mildew caused by Uncinula necator. In a field experiment, a spore suspension of T. harzianum strain T22 or a 6PP solution was applied until fruit harvest. The results indicated that both T. harzianum T22 and 6PP are able to improve crop yield and increase the total amount of polyphenols and antioxidant activity in the grapes. The effects of the isolated natural compounds were comparable with those obtained by using the living fungus.

Total synthesis and biological evaluation of the tetramic acid based natural product harzianic acid and its stereoisomers.

The bioactive natural product harzianic acid was prepared for the first time in just six steps (longest linear sequence) with an overall yield of 22%. The identification of conditions to telescope amide bond formation and a Lacey–Dieckmann reaction into one pot proved important. The three stereoisomers of harzianic acid were also prepared, providing material for comparison of their biological activity. While all of the isomers promoted root growth, improved antifungal activity was unexpectedly associated with isomers in the enantiomeric series opposite that of harzianic acid.

A novel fungal metabolite with beneficial properties for agricultural applications.

Trichoderma are ubiquitous soil fungi that include species widely used as biocontrol agents in agriculture. Many isolates are known to secrete several secondary metabolites with different biological activities towards plants and other microbes. Harzianic acid (HA) is a T. harzianum metabolite able to promote plant growth and strongly bind iron. In this work, we isolated from the culture filtrate of a T. harzianum strain a new metabolite, named isoharzianic acid (iso-HA), a stereoisomer of HA. The structure and absolute configuration of this compound has been determined by spectroscopic methods, including UV-Vis, MS, 1D and 2D NMR analyses. In vitro applications of iso-HA inhibited the mycelium radial growth of Sclerotinia sclerotiorum and Rhizoctonia solani. Moreover, iso HA improved the germination of tomato seeds and induced disease resistance. HPLC-DAD experiments showed that the production of HA and iso HA was affected by the presence of plant tissue in the liquid medium. In particular, tomato tissue elicited the production of HA but negatively modulated the biosynthesis of its analogue iso-HA, suggesting that different forms of the same Trichoderma secondary metabolite have specific roles in the molecular mechanism regulating the Trichoderma plant interaction.

Harzianic acid: a novel siderophore fromTrichoderma harzianum

Agriculture-relevant microorganisms are considered to produce secondary metabolites during processes of competition with other micro- and macro-organisms, symbiosis, parasitism or pathogenesis. Many different strains of the genus Trichoderma, in addition to a direct activity against phytopathogens, are well-known producers of secondary metabolites and compounds that substantially affect the metabolism of the host plant. Harzianic acid is a Trichoderma secondary metabolite, showing antifungal and plant growth promotion activities. This report demonstrates the ability of this tetramic acid to bind with a good affinity essential metals such as Fe(3+) , which may represent a mechanism of iron solubilisation that significantly alters nutrient availability in the soil environment for other microorganisms and the host plant.

Induction of apoptosis against cancer cell lines by four ascomycetes (endophytes) from Malaysian rainforest

Endophytic fungi have been shown to be a promising source of biologically active natural products. In the present study, extracts of four endophytic fungi isolated from plants of the National Park, Pahang were evaluated for their cytotoxic activity and the nature of their active compounds determined. Those extracts exhibiting activity with IC50 values less than 17μg/ml against HCT116, MCF-7 and K562 cell lines were shown to induce apoptosis in these cell lines. Molecular analysis, based on sequences of the rDNA internal transcribed spacers ITS1 and ITS4, revealed all four endophytic fungi to be ascomycetes: three sordariomycetes and a dothideomycete. Six known compounds, cytochalasin J, dechlorogriseofulvin, demethylharzianic-acid, griseofulvin, harzianic acid and 2-hexylidene-3-methyl-succinic acid were identified from a rapid dereplication technique for fungal metabolites using an in-house UV library. The results from the present study suggest the potential of endophytic fungi as cytotoxic agents, and there is an indication that the isolates contain bioactive compounds that mainly kill cancer cells by apoptosis.

Chemotaxonomy of Trichoderma spp. Using Mass Spectrometry-Based

In this study, seven Trichoderma species (33 strains) were classified using secondary metabolite profile-based chemotaxonomy. Secondary metabolites were analyzed by liquid chromatography-electrospray ionization tandem mass spectrometry (LC-ESI-MS-MS) and multivariate statistical methods. T. longibrachiatum and T. virens were independently clustered based on both internal transcribed spacer (ITS) sequence and secondary metabolite analyses. T. harzianum formed three subclusters in the ITS-based phylogenetic tree and two subclusters in the metabolitebased dendrogram. In contrast, T. koningii and T. atroviride strains were mixed in one cluster in the phylogenetic tree, whereas T. koningii was grouped in a different subcluster from T. atroviride and T. hamatum in the chemotaxonomic tree. Partial least-squares discriminant analysis (PLS-DA) was applied to determine which metabolites were responsible for the clustering patterns observed for the different Trichoderma strains. The metabolites were hetelidic acid, sorbicillinol, trichodermanone C, giocladic acid, bisorbicillinol, and three unidentified compounds in the comparison of T. virens and T. longibrachiatum; harzianic acid, demethylharzianic acid, homoharzianic acid, and three unidentified compounds in T. harzianum I and II; and koninginin B, E, and D, and six unidentified compounds in T. koningii and T. atroviride. The results of this study demonstrate that secondary metabolite profiling-based chemotaxonomy has distinct advantages relative to ITSbased classification, since it identified new Trichoderma clusters that were not found using the latter approach.

Harzianic Acid, an Antifungal and Plant Growth Promoting Metabolite from Trichoderma harzianum

A Trichoderma harzianum strain, isolated from composted hardwood bark in Western Australia, was found to produce a metabolite with antifungal and plant growth promoting activity. The structure and absolute configuration of the fungal compound, harzianic acid (1), were determined by X-ray diffraction studies. Harzianic acid showed antibiotic activity against Pythium irregulare, Sclerotinia sclerotiorum, and Rhizoctonia solani. A plant growth promotion effect was observed at low concentrations of 1.

PP2A Inhibitors, Harzianic Acid and Related Compounds Produced by Fungus Strain F‐1531.

AbstractFor Abstract see ChemInform Abstract in Full Text.

PP2A inhibitors, harzianic acid and related compounds produced by fungus strain F-1531.

PP2A inhibitors, harzianic acid and related compounds produced by fungus strain F-1531.