Fungus Trichoderma Longibrachiatum Research Articles

Synergistic Effect of Two Peptaibols from Biocontrol Fungus Trichoderma longibrachiatum Strain 40418 on CO-Induced Plant Resistance.

Trichoderma longibrachiatum is a filamentous fungus used as a biological control agent against different plant diseases. The multifunctional secondary metabolites synthesized by Trichoderma, called peptaibols, have emerged as key elicitors in plant innate immunity. This study obtained a high-quality genome sequence for the T. longibrachiatum strain 40418 and identified two peptaibol biosynthetic gene clusters using knockout techniques. The two gene cluster products were confirmed as trilongin AIV a (11-residue) and trilongin BI (20-residue) using liquid chromatography coupled with tandem mass spectrometry. Further investigations revealed that these peptaibols induce plant resistance to Pseudomonas syringae pv tomato (Pst) DC3000 infection while triggering plant immunity and cell death. Notably, the two peptaibols exhibit synergistic effects in plant-microbe signaling interactions, with trilongin BI having a predominant role. Moreover, the induction of tomato resistance against Meloidogyne incognita showed similarly promising results.

A novel polycyclic quinazoline and three quinolines alkaloids from marine-derived fungus trichoderma longibrachiatum QD01 with anti-bacterial and anti-quorum sensing activities

A novel polycyclic quinazoline alkaloid (1) along with one new natural quinoline alkaloid (2) and two known quinoline alkaloids (3,4) were isolated from the marine-derived fungus Trichoderma longibrachiatum QD01. Structural determinations of those isolates were established by comprehensive spectroscopic analyses and literature comparison. Single-crystal X-ray diffraction analysis of novel compound verified its structure and stereochemistry, representing the first characterised crystal structure of a trimeric-type of tetrahydroquinazoline. Compound 4 exhibited potential antibacterial and anti-quorum sensing activity against C. violaceum and C. violaceum CV026. The sub-MIC of 4 observably decreased the violacein production in C. violaceum CV026 by 55% on 15 μg/mL. Furthermore, molecular docking results revealed that 4 has stronger binding interactions with CviR receptor than ligand C6-HSL with lower binding energy of −8.68 kcal/mol. Hydrogen bond and π–π interactions formed by Trp84, Tyr88, Trp111, and Phe126 were predicted to play an important role in the inhibition against C. violaceum CV026.

Secondary Metabolite Profiling of the Endophytic Fungus Trichoderma longibrachiatum L2D2 Isolated from Anaphalis contorta

In the last few decades, research on endophytic fungi has been increasing due to its applications in agriculture, medicine, and the pharmaceutical industry. Many studies indicate that fungal endophytes produce various types of bioactive compounds. In this study, the endophytic fungus Trichoderma longibrachiatum L2D2 was isolated from the leaf of the medicinal plant Anaphalis contorta and secondary metabolites were collected. The crude extract was analyzed for the presence of seven phytochemicals, and it was observed that alkaloids, flavonoids, phenolics, steroids, tannins, and terpenoids were produced. It was also found that the endophyte extract had a total flavonoid content of 126.07 (µg of quercetin equivalent/mg) and a total phenolic content of 43.97 (µg of gallic acid equivalent/mg). The Gas Chromatography–Mass Spectrometry (GC-MS) analysis reveals the presence of the major compound Dithiooxamide, which has a retention time (RT) of 50.030%, and the Liquid Chromatography–Mass Spectrometry (LC-MS) study shows the most abundant compounds as Hexanal (RT of 3.687 min) in positive ionization and Rosamultin (RT of 24.387 min) in negative ionization. Fourier-Transform Infrared (FTIR) Spectroscopy analysis also shows the presence of alcohol, aldehyde, aliphatic ether, aliphatic primary amine, alkene, alkyl halide, amine, aromatic amine, aromatic compound, carboxylic acid, ketone, phenol, and sulfoxide as functional groups. Further studies, like the purification of bioactive compounds and their biological activities, will reveal the applicability of T. longibrachiatum L2D2 in industries.

Trichoderma longibrachiatum TG1 increases endogenous salicylic acid content and antioxidants activity in wheat seedlings under salinity stress.

Several studies have reported the deleterious effects of excessive salt stress on Triticum aestivum L. seedlings. Seed pretreatment with exogenous salicylic acid (SA) enhances plants to tolerate salt stress. Herein, the present study aims to investigate the potential of plant-growth-promoting fungus Trichoderma longibrachiatum (TG1) to increase the plant growth and enhance the salicylic acid (SA) contents and antioxidants activity in wheat seedlings under different concentrations of salt stress. Wheat seeds were pretreated in TG1 spore suspension before exposure to different salt stresses. Compared with 0, 50, 100, 150 salt stresses, the TG1 and NaCl increased the wheat seeds germination rate, germination potential and germination index significantly; the shoot height and root length were increased by an average of 39.45% and 29.73%, respectively. Compared to NaCl stress across the four concentrations (0, 50, 100, and 150 mM), the TG1 treated wheat seedlings increased SA concentration and phenylalanine ammonia-lyase activity (PAL) by an average of 55.87% and 24.10% respectively. In addition, the TG1+NaCl-treated seedlings increased superoxide dismutase (SOD), peroxidases (POD), and catalase (CAT) activities in the shoot by an average of 47.68%, 23.68%, and 38.65% respectively compared to NaCl-stressed seedlings. Significantly, the genes, SOD, CAT, and POD were relatively up-regulated in the salt-tolerant TG1-treated seedlings at all NaCl concentrations in comparison to the control. Wheat seedlings treated with TG1+NaCl increased the transcript levels of SOD, POD and CAT by 1.35, 1.85 and 1.04-fold at 50 mM NaCl concentration, respectively, compared with 0 mM NaCl concentration. Our results indicated that seeds pretreatment with TG1 could increase endogenous SA of plants and promote seedling growth under salt stress by improving enzymatic antioxidant activities and gene expression.

Front Cover: Eleven‐Residue Peptaibols Isolated from Trichoderma longibrachiatum Rifai DMG‐3‐1‐1and Their Structure‐Activity Relationship (Chem. Biodiversity 9/2022)

Front Cover. Total 23 eleven-residue peptaibols, including five reported ones (1–5) in our previous work, were isolated from the fungus Trichoderma longibrachiatum Rifai DMG-3-1-1, which was obtained from the mushroom Clitocybe nebularis. The structures of the 13 new peptaibols (6–10 and 12–19) were determined by their NMR, MALDI-MS/MS, ECD data and Marfey's analyses. Comparison of the IC50s against the tested cell lines indicated that the 2nd (Gln2/Asn2), 3rd (Ile3/Val3) and 4th (Ile4/Val4) amino acid residues affected their cytotoxicities powerfully. Compounds 2, 5, 9, 11, 21 and 22 also showed moderate antibacterial activities against Staphylococcus aureus MRSA T144. This article analyzed the structure-activity relationship of eleven-residue peptaibols comprehensively, and further enriched the family of peptaibol, as reported by Zhang et al. in their research article at 10.1002/cbdv.202200627.

Eleven-Residue Peptaibols Isolated from Trichoderma longibrachiatum Rifai DMG-3-1-1and Their Structure-Activity Relationship.

Total 23 eleven-residue peptaibols, including five reported ones (1-5) in our previous work, were isolated from the fungus Trichoderma longibrachiatum Rifai DMG-3-1-1, which was obtained from the mushroom Clitocybe nebularis (Batsch) P. Kumm. The structures of the 13 new peptaibols (6-10 and 12-19) were determined by their NMR and MALDI-MS/MS data, their absolute structures were further determined by Marfey's analyses and their ECD data. Careful comparison of the structures of 1-23 showed that only seven residues varied including the 2nd (Gln2 /Asn2 ), 3rd (Ile3 /Val3 ), 4th (Ile4 /Val4 ), 6th (Pro6 /Hyp6 ), 8th (Leu8 /Val8 ), 10th (Pro10 /Hyp10 ) and 11th (Leuol11 /Ileol11 /Valol11 ) residues. Comparison of the IC50 s against the three tested cell lines of 1-23 indicated that 2nd, 3rd and 4th amino acid residues affected their cytotoxicities powerfully. Compounds 2, 5, 9, 11, 21 and 22 showed moderate antibacterial activities against Staphylococcus aureus MRSA T144, which also showed stronger cytotoxicities against BV2 and MCF-7 cells.

Longibrachiamide A, a 20-Residue Peptaibol Isolated from Trichoderma longibrachiatum Rifai DMG-3-1-1.

Longibrachiamide A (1), a new 20-residue peptaibol, along with three known ones (2-4), were isolated from the fungus Trichoderma longibrachiatum Rifai DMG-3-1-1, isolated from a mushroom Clitocybe nebularis (Batsch) P. Kumm, which was collected from coniferous forest of northeast China in our previous work. The structure of longibrachiamide A (1) was determined by its NMR and ESI-MS/MS data, the absolute configuration of 1 was further determined by Marfey's analyses. And the complete NMR data of 2-4 were also reported for the first time. The similar CD spectra of 1-4 showed that they all had mixed 310 -/α-helical conformations. Compounds 1-4 showed strong cytotoxicities against BV2, A549 and MCF-7 cells, and also showed moderate inhibitory effects against the tested Gram-positive bacteria, including MRSA T144 and VRE-10.

Sesquiterpene and Sorbicillinoid Glycosides from the Endophytic Fungus Trichoderma longibrachiatum EN-586 Derived from the Marine Red Alga Laurencia obtusa.

An unusual sesquiterpene glycoside trichoacorside A (1) and two novel sorbicillinoid glycosides sorbicillisides A (2) and B (3), together with a known compound sorbicillin (4), were isolated and identified from the culture extract of an endophytic fungus Trichoderma longibrachiatum EN-586, obtained from the marine red alga Laurencia obtusa. Trichoacorside A (1) is the first representative of a glucosamine-coupled acorane-type sesquiterpenoid. Their structures were elucidated based on detailed interpretation of NMR and mass spectroscopic data. The absolute configurations were determined by X-ray crystallographic analysis, chemical derivatization, and DP4+ probability analysis. The antimicrobial activities of compounds 1–4 against several human, aquatic, and plant pathogens were evaluated.

Low Virulence of the Fungi Escovopsis and Escovopsioides to a Leaf-Cutting Ant-Fungus Symbiosis.

Eusocial insects interact with a diversity of parasites that can threaten their survival and reproduction. The amount of harm these parasites cause to their hosts (i.e., their virulence) can be influenced by numerous factors, such as the ecological context in which the parasite and its host are inserted. Leaf-cutting ants (genera Atta, Acromyrmex and Amoimyrmex, Attini: Formicidae) are an example of a eusocial insect whose colonies are constantly threatened by parasites. The fungi Escovopsis and Escovopsioides (Ascomycota: Hypocreales) are considered a highly virulent parasite and an antagonist, respectively, to the leaf-cutting ants’ fungal cultivar, Leucoagaricus gongylophorus (Basidiomycota: Agaricales). Since Escovopsis and Escovopsioides are common inhabitants of healthy colonies that can live for years, we expect them to have low levels of virulence. However, this virulence could vary depending on ecological context. We therefore tested two hypotheses: (i) Escovopsis and Escovopsioides are of low virulence to colonies; (ii) virulence increases as colony complexity decreases. For this, we used three levels of complexity: queenright colonies (fungus garden with queen and workers), queenless colonies (fungus garden and workers, without queen) and fungus gardens (without any ants). Each was inoculated with extremely high concentrations of conidia of Escovopsis moelleri, Escovopsioides nivea, the mycoparasitic fungus Trichoderma longibrachiatum or a blank control. We found that these fungi were of low virulence to queenright colonies. The survival of queenless colonies was decreased by E. moelleri and fungus gardens were suppressed by all treatments. Moreover, E. nivea and T. longibrachiatum seemed to be less aggressive than E. moelleri, observed both in vivo and in vitro. The results highlight the importance of each element (queen, workers and fungus garden) in the leaf-cutting ant-fungus symbiosis. Most importantly, we showed that Escovopsis may not be virulent to healthy colonies, despite commonly being described as such, with the reported virulence of Escovopsis being due to poor colony conditions in the field or in laboratory experiments.

Transcriptome modulation by the beneficial fungus Trichoderma longibrachiatum drives water stress response and recovery in tomato

Trichoderma spp. are beneficial soil microorganisms used in sustainable agriculture for their ability to enhance plant performance under different environments. However, Trichoderma-activated mechanisms that help plants to cope with water stress are still not completely defined. We investigated morpho-physiological, biochemical and transcriptomic responses to PEG-induced short severe water stress in Trichoderma longibrachiatum-inoculated and non-inoculated Solanum lycopersicum. Trichoderma had significant biostimulation effects on the plant and, after stress, allowed recovery of growth and photosynthesis to the levels of unstressed plants. Whole-transcriptome analysis was carried out after 1 day of 15 % PEG treatment in 22-day Trichoderma-inoculated and non-inoculated plants. Under non-stress conditions, Trichoderma triggered an extensive transcriptional reprogramming, specifically modulating the expression of classes of transcription factors and of genes involved in photosynthesis, antioxidant defences and maintenance of a juvenile state. Though the effects of water stress were predominant, mainly boosting transcription of stress-responsive genes, pre-treatment with Trichoderma specifically affected genes involved in mitigation of stress damage. Our findings provide new insights into the plant interplay with Trichoderma, useful to further exploit rhizosphere fungi for the improvement of plant performance under limiting environments.

Longibramides A-E, Peptaibols Isolated from a Mushroom Derived Fungus Trichoderma longibrachiatum Rifai DMG-3-1-1.

Five new peptaibols, longibramides A-E (1-5) with 11 amino acid residues, were isolated from a fungus Trichoderma longibrachiatum Rifai DMG-3-1-1, which was isolated from a mushroom Clitocybe nebularis (Batsch) P. Kumm collected from coniferous forest in the subboreal area of northeast China. The structures of longibramides A-E were determined by their spectroscopic data (NMR and MS-MS spectra), their absolute configurations were determined by X-ray diffractions and Marfey's analyses. The X-ray diffractions of longibramides A, B, and the similar CD spectra of A-E showed that they all had α-helix conformations. Longibramides B and E showed moderate cytotoxicities against BV2 and MCF-7 cells and also showed some inhibitory effects against methicillin-resistant Staphylococcus aureus MRSA T144. L-trans-Hyp was not commonly found in natural peptaibols, which was the 6th or 10th amino acid residue in longibramides C-E. The X-ray diffractions of longibramides A and B afforded the accuracy conformations of their secondary structures, which maybe help to interpret the structure-activity relationships of the family of peptaibols in the future.

Antibacterial Activities of the Extracts of Sponge-Associated Fungus Trichoderma longibrachiatum against Pathogenic Bacteria

This study aims to explore the antibacterial potential of a sponge-associated fungus Trichoderma longibrachiatum isolated from Ternate waters, North Maluku, Eastern Indonesia. Various culture media were used to stimulate the production of secondary metabolites in T. longibrachiatum. The isolate was cultured in various media for 6-9 days. Then, the antibacterial activities of the ethyl acetate extracts were assayed against pathogenic bacteria of Multi-Drug Resistant (MDR) strain (Pseudomonas aeruginosa, Staphylococcus aureus, Klebsiella pneumoniae, and Bacillus cereus). The results showed that all extracts had similar profiles on the thin layer chromatography. However, two of the most potent extracts were produced from the PCA and MEA media for 9 days. These extracts inhibited methicillin-resistant S. aureus (MRSA) (12.48 mm and 12.27 mm); B. cereus (12.11 mm and 12.12 mm); K. pneumoniae (12.40 mm and 10.76 mm); and P. aeruginosa (11.59 mm and 8.69 mm) at concentrations 500 mg/disc. In conclusion, the fungus T. longibrachiatum that was cultured in PCA and MEA media had the potential to produce antibacterial compounds against MDR pathogens and both had similar compounds. Meanwhile, the ethyl acetate extracts from fungus cultured in the TPA and TA media were inactive against all tested bacteria

The Putative Methyltransferase TlLAE1 Is Involved in the Regulation of Peptaibols Production in the Biocontrol Fungus Trichoderma longibrachiatum SMF2.

The biocontrol fungus Trichoderma longibrachiatum SMF2 secretes a large quantity of peptaibols that have been shown to have a range of biological activities and therefore great application values. However, the mechanism of the regulatory expression of peptaibols is still unclear. The putative methyltransferase LaeA/LAE1 is a global regulator involved in the biosynthesis of some secondary metabolites in filamentous fungi. In this study, we demonstrated that the ortholog of LaeA/LAE1 in the biocontrol fungus T. longibrachiatum SMF2, TlLAE1, plays an important role in the regulation of peptaibols production. Deletion of Tllae1 resulted in a slight negative impact on mycelial growth, and a significant defect in conidial production. Deletion of Tllae1 also compromised the production of peptaibols to a large degree. Further analyses indicated that this defect occurred at the transcriptional level of the two synthetases-encoding genes, tlx1 and tlx2, which are responsible for peptaibols production. By contrast, constitutive expression of Tllae1 in T. longibrachiatum SMF2 led to 2-fold increased peptaibols production, suggesting that this is a strategy to improve peptaibols production in Trichoderma fungi. These results demonstrate the important role of LAE1 in the regulation of peptaibols production in T. longibrachiatum SMF2.

Aspergillus galactomannan detection: Trichoderma as a cause of positive results.

Aspergillus galactomannan immunoassay is a main diagnostic and monitoring tool in medical mycology. However, the specificity of the method can be skewered by the presence of several other fungi. Trying to diagnose a possible fungal infection of the lower respiratory tract in a haematology patient, it appeared that the fungus Trichoderma longibrachiatum is an additional probable cause of positive galactomannan results. Although, that Trichoderma is a rare but emerging pathogen in immunocompromised patients, the above information could be a caution point in the clinical evaluation of diagnostic results.

The Hydrophobin HYTLO1 Secreted by the Biocontrol Fungus Trichoderma longibrachiatum Triggers a NAADP-Mediated Calcium Signalling Pathway in Lotus japonicus.

Trichoderma filamentous fungi are increasingly used as biocontrol agents and plant biostimulants. Growing evidence indicates that part of the beneficial effects is mediated by the activity of fungal metabolites on the plant host. We have investigated the mechanism of plant perception of HYTLO1, a hydrophobin abundantly secreted by Trichoderma longibrachiatum, which may play an important role in the early stages of the plant-fungus interaction. Aequorin-expressing Lotus japonicus suspension cell cultures responded to HYTLO1 with a rapid cytosolic Ca2+ increase that dissipated within 30 min, followed by the activation of the defence-related genes MPK3, WRK33, and CP450. The Ca2+-dependence of these gene expression was demonstrated by using the extracellular Ca2+ chelator EGTA and Ned-19, a potent inhibitor of the nicotinic acid adenine dinucleotide phosphate (NAADP) receptor in animal cells, which effectively blocked the HYTLO1-induced Ca2+ elevation. Immunocytochemical analyses showed the localization of the fungal hydrophobin at the plant cell surface, where it forms a protein film covering the plant cell wall. Our data demonstrate the Ca2+-mediated perception by plant cells of a key metabolite secreted by a biocontrol fungus, and provide the first evidence of the involvement of NAADP-gated Ca2+ release in a signalling pathway triggered by a biotic stimulus.

Identification of the antifungal activity of Trichoderma longibrachiatum T6 and assessment of bioactive substances in controlling phytopathgens

Biological control with microbial antagonists is considered an alternative approach for controlling plant diseases. Trichoderma species are one of the potential fungal biocontrol agents in suppression of soil-borne pathogens. However, the mechanism and characterization of Trichoderma spp. in inhibiting different phytopathogenic fungi are largely unknown. In this study, we investigated the antagonistic potential of the endophytic fungus Trichoderma longibrachiatum T6 as a biocontrol agent against different phytopathogenic fungi and the associated antagonistic mechanism with bioactive substances. We found that the fermentation and crude extract of T. longibrachiatum T6 had a broad spectrum and potent activity inhibiting the growth of eleven phytopathogens evaluated, and of which, the inhibitory rate against Valsa mali reached 95% at 5 days after incubation. Ten fractions and six sub-fractions of bioactive substances were obtained on silica gel G chromatography and Sephadex LH-20 columns. One of the sub-fractions (coded sub-Fr.4f) exhibited highest inhibition against the pathogen V. mail, with the inhibitory rate of 80.64% at Day 5 of the treatment. Four key chemical inhibitors were identified: (i) 1, 2-Benzenedicarboxylicacid, bis (2-methylpropyl) ester (DIBP) (C16H22O4); (ii) (Z)-octadec-9-enoic acid (C18H34O2); (iii) 1, 2-Benzenedicarboxylic acid, mono (2-ethylhexyl) ester (MEHP) (C16H22O4); and (iv) (Z)-13-Docosenamide (C22H43NO), using spectroscopic and nuclear magnetic resonance data. Two fungicidal compounds DIBP and MEHP provided significantly greater antifungal activities than the other compounds in the inhibition of the V. mail growth. There was a significant linear relationship between the monomer compounds MEPH or DIBP and the inhibitory rates of V. mail; at the concentration of 200 μg mL−1, the inhibitory rate reached over 86% or 78%. We conclude that the strain of T. longibrachiatum T6 can serve as an effective biocontrol agent against V. mali and the mechanism for this function was due to the secondary metabolites with effective bioactive substance.

Purification and characterization of cellulase from a novel isolate of Trichoderma longibrachiatum

ABSTRACTIn the present study, the isolation, purification and characterization of a complex enzyme, cellulase, was carried out using a new local isolate of the fungus Trichoderma longibrachiatum (KM274866) from wood chips, with a view to explore its utility in the biofuel industry. The fungus was grown on a selected natural substrate, sugarcane bagasse, based on cost considerations for enzyme production. The enzyme was purified 14.82 fold with a yield of 25.8% and specific activity of 30 U/mg of protein. The molecular mass of the enzyme was found to be 67 ± 1 KDa. The optimum pH was 4.8, but the enzyme was stable at a pH range of 3–6. Optimum temperature was 45 °C, but the stability range of the enzyme was 30–55 °C. Metal ions such as Ca2+, Na+, Mg2+, Zn2+ and Fe2+ enhanced enzyme activity. Triton X100 in the medium resulted in a significant increase of enzyme activity compared to other group specific reagents. KM and Vmax for the enzyme were found to be 0.121 mg/ml and 0.421 μmol/min, respectively, against the substrate carboxy methyl cellulose. As the enzyme is from an inexpensive source, it will be most useful in the preparation of bioethanol for the biofuel industry.

Production of a generic microbial feedstock for lignocellulose biorefineries through sequential bioprocessing

Lignocellulosic materials, mostly from agricultural and forestry residues, provide a potential renewable resource for sustainable biorefineries. Reducing sugars can be produced only after a pre-treatment stage, which normally involves chemicals but can be biological. In this case, two steps are usually necessary: solid-state cultivation of fungi for deconstruction, followed by enzymatic hydrolysis using cellulolytic enzymes. In this research, the utilisation of solid-state bioprocessing using the fungus Trichoderma longibrachiatum was implemented as a simultaneous microbial pretreatment and in-situ enzyme production method for fungal autolysis and further enzyme hydrolysis of fermented solids. Suspending the fermented solids in water at 50°C led to the highest hydrolysis yields of 226mg/g reducing sugar and 7.7mg/g free amino nitrogen (FAN). The resultant feedstock was shown to be suitable for the production of various products including ethanol.

Deep RNA sequencing reveals a high frequency of alternative splicing events in the fungus Trichoderma longibrachiatum.

BackgroundAlternative splicing is crucial for proteome diversity and functional complexity in higher organisms. However, the alternative splicing landscape in fungi is still elusive.ResultsThe transcriptome of the filamentous fungus Trichoderma longibrachiatum was deep sequenced using Illumina Solexa technology. A total of 14305 splice junctions were discovered. Analyses of alternative splicing events revealed that the number of all alternative splicing events (10034), intron retentions (IR, 9369), alternative 5’ splice sites (A5SS, 167), and alternative 3’ splice sites (A3SS, 302) is 7.3, 7.4, 5.1, and 5.9-fold higher, respectively, than those observed in the fungus Aspergillus oryzae using Illumina Solexa technology. This unexpectedly high ratio of alternative splicing suggests that alternative splicing is important to the transcriptome diversity of T. longibrachiatum. Alternatively spliced introns had longer lengths, higher GC contents, and lower splice site scores than constitutive introns. Further analysis demonstrated that the isoform relative frequencies were correlated with the splice site scores of the isoforms. Moreover, comparative transcriptomics determined that most enzymes related to glycolysis and the citrate cycle and glyoxylate cycle as well as a few carbohydrate-active enzymes are transcriptionally regulated.ConclusionsThis study, consisting of a comprehensive analysis of the alternative splicing landscape in the filamentous fungus T. longibrachiatum, revealed an unexpectedly high ratio of alternative splicing events and provided new insights into transcriptome diversity in fungi.Electronic supplementary materialThe online version of this article (doi:10.1186/s12864-015-1251-8) contains supplementary material, which is available to authorized users.

Tomato Below Ground–Above Ground Interactions: Trichoderma longibrachiatum Affects the Performance of Macrosiphum euphorbiae and Its Natural Antagonists

Below ground and above ground plant-insect-microorganism interactions are complex and regulate most of the developmental responses of important crop plants such as tomato. We investigated the influence of root colonization by a nonmycorrhizal plant-growth-promoting fungus on direct and indirect defenses of tomato plant against aphids. The multitrophic system included the plant Solanum lycopersicum ('San Marzano nano'), the root-associated biocontrol fungus Trichoderma longibrachiatum strain MK1, the aphid Macrosiphum euphorbiae (a tomato pest), the aphid parasitoid Aphidius ervi, and the aphid predator Macrolophus pygmaeus. Laboratory bioassays were performed to assess the effect of T. longibrachiatum MK1, interacting with the tomato plant, on quantity and quality of volatile organic compounds (VOC) released by tomato plant, aphid development and reproduction, parasitoid behavior, and predator behavior and development. When compared with the uncolonized controls, plants whose roots were colonized by T. longibrachiatum MK1 showed quantitative differences in the release of specific VOC, better aphid population growth indices, a higher attractiveness toward the aphid parasitoid and the aphid predator, and a quicker development of aphid predator. These findings support the development of novel strategies of integrated control of aphid pests. The species-specific or strain-specific characteristics of these below ground-above ground interactions remain to be assessed.