Trichoderma Polysporum Research Articles

Production and partial purification of an innovative heat resistant α-keratinase with some remarkable medical and industrial applications

Background and objectives Keratinase has ultimate practical importance in industry, medicine, food industry and waste management fields. Their applications in wool and silk are as good cleaners and in leather industry as the best ever green dehairing agents providing high leather quality, as well they are used as crucial components of sophisticated detergents. Their medical prospective applications are in prion degradation and human callus removal. They convert keratinaceous wastes to valuable products saving the environment from hard keratin waste pollution. Bacteria, fungi and actinomycetes are effective keratinase producers and they are considered the most suitable sources. This study aims to formulate the production medium and to pinpoint the proper physiological conditions for the potent microorganism producing an efficient α-keratinase enzyme. The partial purification of the crude enzyme was successfully performed. The effect of the reaction temperature on both the crude and the partially purified enzyme (PPE) was duly studied with the thermostability of PPE. Some important applications have been implemented on PPE and these include leather dehairing, cloth stain removal, and topical treatment of human callus. Materials and Methods Thirteen recommended microbial strains were screened for effective and applicable α-keratinase productivity. Optimization of the cultural conditions for extracellular enzyme production and also the partial purification of the crude enzyme by ammonium sulphate salting out or by ethanol or acetone precipitation were carried out. The effect of reaction temperature on the enzyme and its thermostability were studied. Finally, the efficiency of the PPE on leather dehairing, stain removal, and human callus treatment was explored. Results and conclusion Among the 13 organisms screened, the fungal strain Trichoderma polysporum HZ-31 was the most potent producer of an influencial α-keratinase. The maximum α-keratinase activity of 58.2 UmL−1 was obtained by the previous-mentioned strain after 5-days fermentation medium containing (%, w/v): whole chicken feathers 0.5, glucose 0.2, peptone 0.5, yeast extract 0.5, K2HPO4 0.1, KH2PO4 0.3, CaCl2 0.1, MgSO4 0.1, and pH 7.0. Acetone fractionation of the crude keratinase was the most proper and offered the most promising keratinase fraction PPE at 80–90% acetone. This fraction had high thermostability and was kept at 55°C for more than 98% of its original activity after 60 min heating and this temperature (55°C) was also the optimum for 2 h enzymatic reaction. Conclusively, the present study succeeded in the achievement of a constitutive extracellular alkaline α-keratinase, which successfully proceeded to complete leather unhairing after 12–16 h at 37°C, afforded high performance to cloth blood stain removal with Arial detergent after 2 h at 50°C and complete degradation of the human callus after 4 h at 50°C.

Whole genome sequencing and analysis of the weed pathogen Trichoderma polysporum HZ-31

In order to resolve the key genes for weed control by Trichoderma polysporum at the genomic level, we extracted the genomic DNA and sequenced the whole genome of T. polysporum strain HZ-31 on the Illumina Hiseq platform. The raw data was cleaned up using Trimmomatic and checked for quality using FastQC. The sequencing data was assembled using SPAdes, and GeneMark was used to perform gene prediction on the assembly results. The results showed that the genome size of T. polysporum HZ-31 was 39,325,746 bp, with 48% GC content, and the number of genes encoded was 11,998. A total of 148 tRNAs and 45 rRNAs were predicted. A total of 782 genes were annotated in the Carbohydrase Database, 757 genes were annotated to the Pathogen-Host Interaction Database, and 67 gene clusters were identified. In addition, 1023 genes were predicted to be signal peptide proteins. The annotation and functional analysis of the whole genome sequence of T. polymorpha HZ-31 provide a basis for the in-depth study of the molecular mechanism of its herbicidal action and more effective utilization for weed control.

Co-infection with two novel mycoviruses affects the biocontrol activity of Trichoderma polysporum

This study reports the whole genome sequence of two double-stranded RNA viruses (mycoviruses) that co-infected an isolate of Trichoderma polysporum NFCF205 and the interactions between fungus and virus. Based on genome size, organization, sequence similarity, and phylogenic analysis, one of these is best characterized as a new member of the proposed family “Fusagraviridae”, and accordingly suggest that it be referred to as Trichoderma polysporum fusagravirus 1 (TpFGV1). The other is best classified as a new strain of the genus Alphapartitivirus in the family Partitiviridae, and should be designated Trichoderma polysporum partitivirus 1 from T. polysporum NFCF205 (TpPV1). By single spore isolation, virus-free or singly-infected isogenic strains were obtained and compared to determine the biological functions of the viruses. The colony morphology of the co-infected parental strain showed the characteristic spiraled hairy and fluffy mycelia, while both the singly-infected and virus-free strain rarely showed the conspicuous aerial mycelia. The growth rate of the co-infected strain was slightly, but nevertheless statistically significantly, higher on PDA. Interestingly, conidia production was observed to have significantly increased in the co-infected strain while no difference was seen in the others. Growth inhibition measured by dual-culturing with Rhizoctonia solani revealed a significant difference between the co-infected strain and a TpPV1-infected strain. However, the secreted soluble compounds in the co-infected strain showed the least antimicrobial activity. Moreover, antimicrobial activities via volatile organic compounds (VOCs), which signify strong biocontrol activity by Trichoderma spp., was the lowest in the co-infected strain. The profiles and amount of representative VOCs in the assessed strains, as measured by gas chromatography-mass spectrometry (GC/MS/MS), were affected by virus-infection. Virus infection affected colony morphology, conidia production, and biocontrol activities of T. polysporum. Most interestingly, virus-virus interaction was observed and measured in the co-infected strain, as their symptoms differed from those of the singly-infected strains.

Comparative assessment of indoor and outdoor air environment of poultry farms in Edo State, Nigeria

Intensive poultry farming creates the ideal environment for pathogen concentration and transmission. The presence of thousands of birds in an enclosed, warm, and dusty atmosphere is ideal for the transmission of infectious diseases from birds to humans. This study was conducted to assess the indoor and outdoor air quality of different poultry types in Edo State, Nigeria. The physicochemical conditions of the air around the poultry environments differed with location and poultry types. The concentrations of carbon dioxide (CO2,), nitrous oxide (N2O), hydrogen sulphide (H2S) as well as particulate matter (PM10) were all within recommended limits established by the World Health Organization. However, significant elevations in Ammonia (NH3) and sulphur dioxide (SO2) levels were observed in substandard poultry farms across the locations. Total bacterial counts ranged from 1.38CFU/m5 – 90.35 x105CFU/m3 irrespective of location and poultry type. Within the poultry types, bacteria count inside the poultry environment (3.11 x105CFU/m3) significantly differed from concentrations outside the poultry environment (22.58 x105CFU/m3, p<0.05). The Lowest microbial counts were obtained in the standard poultry farms. Molecular identifications revealed the presence of Escherichia coli, Streptococcus pyogenes, Staphylococcus aureus, Pseudomonas aeruginosa, Klebsiella pneumonia, Bacillus subtilis as the bacterial isolates whereas Fusarium oxysporum, Aspergillus niger, Rhizopus stolonifer, Trichoderma polysporum, Aspergillus fumigatus were the fungal isolates. Staphylococcusaureus was the most predominant bacterial species (25%) while Aspergillus niger was the most predominant fungal species (30%).

Biological elicitor potential of endospheric Trichoderma and derived consortia against pepper (Capsicum annuum L.) leaf curl virus

Pepper leaf curl virus (PeLCV), transmitted by whitefly is a cosmopolitan plant viral disease hampering a wide range of crops. Chemical elicitors have been used to curb the trend regardless of their setbacks on environment and human kind. Herein, we report the suppressive effects of Trichoderma Polysporum T1, Atroviridae T2 and Harzianum T8 and their consortia against PeLCV. They endophytically colonised pepper tissue with significant shift in auxin leading to accumulated biological yield. Likewise, Trichoderma-induced innate host immunity priming and stress tolerance may be mediated by the triggered phenylpropanoid biosynthesis (183% more phenolic content). The capability of Trichoderma bioagents to release salicylic acid under in vitro conditions appear to have prominent role in orchestrating PeLCV suppression (up to 50%). Interestingly, no difference was recorded in the specific activity of the destressing enzymes indicating a likely early ROS accumulation at infection sites leading to restricted virus spread. Overall, Trichoderma could help to counteract viral diseases. Highlights • T. harzianum T8, Atroviridae T2 and Polysporum T1 have the capability to reduced PeLCV in peppers plants • These Trichoderma showed a best capacity in consortia than single against PeLCV • These Trichoderma produce some phytohormones and help plant for growing and plant defence against biotic attack.

Expression stability of internal reference gene in response to Trichoderma polysporum infection in Avena fatua L.

Trichoderma polysporum was a pathogenic fungi which showed strong pathogenicity to Avena fatua L. in recent study. The stress response of A. fatua to T. polysporum is mediated by the regulation of gene expression. Quantification of the expression of genes requires normalizing RT-qPCR data using reference genes with stable expression in the system studied as internal standards. To construct a RT-qPCR system suitable for response of A. fatua to T. polysporum, and screen stable internal reference genes, GeNorm, NormFinder, BestKeeper and RefFinde were used to perform SYBR Green-based RT-qPCR analysis on eight candidate internal reference genes (18S, 28S, TUA, UBC, ACT, GAPDH, TBP and EF-1α) in A. fatua samples after inoculation of T. polysporum Strain HZ-31. The results showed that TBP, 18S and UBC were the most stable internal reference genes, TBP and TUA, TBP and GAPDH, 18S and TBP, UBC and 18S were the most suitable combination of the two internal reference genes, which could be used as internal reference genes for functional gene expression analysis during the interaction between T. polysporum and A. fatua. This is the first study describing a set of reference genes with a stable expression under fungi stress in A. fatua. These genes are also candidate reference genes of choice for studies seeking to identify stress-responsive genes in A. fatua.

Alkaline Pre-Treatment of Coal Fly Ash as Bio-Silica Fertilizer

This study deals with the pre-treatment of coal fly ash (CFA) by using alkaline substance to improve water solubility of Si which in turn readily available to the plants. Selected weight ratios of CFA/NaOH (s:s) were tested and the highest H4SiO4 yield ratio was selected for further study. X-ray diffraction and scanning electron microscopy analyses were performed to confirm the evidence of structural changes of the CFA upon alkaline treatment. To improve SiO2 dissolution, seven Si-solubilizing fungi, i.e., Aspergillus niger BCC194, A. niger K0909, A. niger A1601, Trichoderma polysporum, T. viride, T. pseudokoningii, and Trichoderma spp, were each inoculated onto pre-treated ash. The results indicated that the relationships between ratio of CFA/NaOH and total and soluble Si were linier (R2 = 0.97** and 0.96**, respectively). Total SiO2 values range from 10.43% to 13.02%, whereas soluble Si contents were 2.30% - 2.64% improved about 300 times compared to un-treated CFA. Both XRD and SEM analyses indicated that alkaline treatment to CFA caused particle damages resulting in increasing soluble Si. Inoculation of pre-treated CFA by T. polysporum up to twelve days of incubation yielded the highest soluble Si. Each fungal species grown on Bunt & Rovira solid media enriched with CFA as Si-source expressed significantly different ability in solubilizing Si from CFA. Citric acid was shown to be stronger compared to acetic and oxalic acids in solubilizing Si from CFA.

Screening of endophytic fungi against southern blight disease pathogen-Sclerotium delphinii in Dendrobium catenatum

In order to screen the endophytic fungi that can enhance the host(Dendrobium catenatum) resistance to Sclerotium delphinii, the antagonism between each of the 43 endophytic fungi and the pathogen S. delphinii were tested. The results showed that 6 endophytic fungi(DCR2, DCR5, DCR21, DCR22, DCR42, DCR43) have strong activities against the pathogen, the inhibition rates were 49.2%, 49.2%, 47.2%, 56.2%, 53.2%, 48.0%, respectively. Then D. catenatum plantlets were inoculated with both S. delphinii and each of these six endophytic fungi. As a result, the incidence rates of leaves and stems of the D. catenatum plantlets inoculated with DCR2 and the pathogen were both significantly lower than those with other treatments, and the plantlet death rate was 0. It showed that DCR2 Trichoderma polysporum could effectively inhibit the southern blight disease of D. catenatum. Through the endophytic fungal re-isolation test, it was found that DCR2 can colonize in the roots, stems, and leaves of D. catenatum. The research will provide new ideas for the prevention and treatment of the southern blight disease of D. catenatum. It is also significant for reducing pesticide use, ensuring food safety, and promoting the sustainable development of D. catenatum industry. Furthermore, it will provide a basis for the disease control in other crops.

Enhanced solubilization of insoluble silicate from quartz and zeolite minerals by selected Aspergillus and Trichoderma species

Silicon (Si) is a major component of sand, silt and clay particles of soils. Available silica as silicic acid (H4SiO4) present in soil solution is considerably low, only in the range of 3.5–40.0 mg Si L-1. To improve plant-available Si in the soil, silicate-solubilizing fungi (SSF) are potentially important in solubilizing insoluble forms of silicate (SiO2). The objectives of this study were to determine silicate solubilizing capacity and organic acid produced by seven SSF isolates on Bunt and Rovira media by using 0.25% (w/v) magnesium trisilicate (Mg2O8Si3), quartz, and zeolite as a silica source. Determination of SSF isolates potential in Si solubilization was carried out in a completely randomized design with three silica sources and three replicates. The results indicated that all SSF were capable of producing acetic, citrate, and oxalic acids and enhancing the solubilization of insoluble silicates. Trichoderma polysporum and Aspergillus niger BCCF194 were the best isolates of SSF. Furthermore, there was significantly (p<0.05) positive correlation between solubilizing silicate capacity by using quartz or zeolite as a silica source on Bunt and Rovira media with incubation time (R2 = 0.79-0.99) and citric acid production (R2= 0.97-0.99) from T. polysporum and A. niger BCCF194

Biological weed control using Trichoderma polysporum strain HZ-31

To develop a potential bio herbicide, herbicide activity and crop safety of fungal strain HZ-31 isolated from naturally infected weed Cirsium arvense (L.) Scop. were investigated. The study was conducted in vitro and in vivo during the summers of 2017 and 2018. Strain HZ-31 showed broad-spectrum herbicidal activity, both in vitro and in vivo, when targeting Elsholtzia densa Benth., Polygonum lapathifolium L., Lepyrodiclis holosteoides (C.A. Mey.) Fenzl ex Fisch. & C.A. Mey., Avena fatua L., Chenopodium album L. and Polygonum aviculare L. Exposure to HZ-31 in vitro induced heavy levels of damage in the leaves of E. densa, A. fatua, and P. aviculare. Exposure to HZ-31 in vivo resulted in high mortality in E. densa, A. fatua, and P. lapathifolium. Although the exposure of various weeds to HZ-31 caused severe damage, the strain did not cause any deleterious effects in Vicia faba L. and Pisum sativum L., two of the five crops tested. Our results suggest that fungal strain HZ-31 could be a potential mycoherbicide candidate for weed control in V. faba and P. sativum fields. Based on its morphological characteristics and ITS nucleotide sequence analysis, the fungus was classified as Trichoderma polysporum (Louk:Fr.) Rifai. New perspectives for weeds control by T. polysporum and its use in V. faba and P. sativum crops were prospected, considering the bioherbicide selectivity described in this study.

Bioremediation of Spent Engine Oil Contaminated Soils Using Indigenous Fungi Species

Spent engine oil is derived from lubricating oil which has been used to lubricate various internal combustion engines and it is drained out for disposal during servicing of the engine. Spent engine oil causes great damage to soil and soil microflora when disposed indiscriminately. Thus, the bioremediation of spent engine oil contaminated soil was studied using indigenous degrading fungi isolated from hydrocarbon contaminated soils obtained from automobile mechanic workshops located at both Okpe and Uvwie Local Government Areas of Delta State, in the Niger Delta region of Nigeria. Three (3) fungi isolates with high engine oil biodegradability potential were used for the spent engine oil (SEO) bioremediation study. The fungi isolates used for the test were identified as, <em>Aspergillus glaucus</em>, <em>Trichoderma polysporum</em> and <em>Talaromyces flavus</em>using the API 20C method. The test microcosms were incubated for four weeks at 28 ± 2<sup>o</sup>C. Physicochemical parameters such as, Sulphate concentrations, Total petroleum hydrocarbon, Nitrate concentrations, Phosphate concentrations, Total organic carbon content, pH and Hydrocarbon utilizing fungi counts were monitored weekly using standard ASTM methods to assess the biodegradation of the spent engine oil. At the end of the test duration, <em>Talaromyces flavus </em>recorded the highest percentage spent engine oil biodegradation (69.66%) for the 5% SEO experimental set up. Similarly, <em>Aspergillus glaucus </em>recorded the highest percentage SEO biodegradation (66.16%) for the 10% experimental set up. Thus, <em>Talaromyces flavus </em>and <em>Aspergillus glaucus </em>could be used to effectively bioaugment the bioremediation process of spent engine oil contaminated soils to restore the soil to its original state within a short period of time.

Diversity and bioprospecting of cultivable fungal assemblages in sediments of lakes in the Antarctic Peninsula

We recovered 195 fungal isolates from the sediments of different lakes in the Antarctic Peninsula, which were screened to detect bioactive compounds. Forty-two taxa belonging to the phyla Ascomycota, Basidiomycota, and Mortierellomycota were identified. Thelebolus globosus, Antarctomyces psychrotrophicus, Pseudogymnoascus verrucosus, Vishniacozyma victoriae, and Phenoliferia sp. were found to be the most prevalent. The fungal assemblages showed high diversity and richness, but low dominance values. However, the diversity indices and fungal distribution ranged according to the different lake sediments. Sixty fungal extracts displayed at least one biological activity against the evaluated targets. Among them, Pseudogymnoascus destructans showed selective trypanocidal activity, Cladosporium sp. 1 and Trichoderma polysporum showed antifungal activity, and Pseudogymnoascus appendiculatus and Helotiales sp. showed high herbicidal activity. We detected a rich and diverse fungal community composed of cold cosmopolitan and psychrophilic endemic taxa recognized as decomposers, symbiotics, pathogens, and potential new species, in the sediments of Antarctic lakes. The dynamics and balance of this fungal community represents an interesting aquatic web model for further ecological and evolutionary studies under extreme conditions and potential climate changes in the regions. In addition, we detected fungal taxa and isolates able to produce bioactive compounds that may represent the source of prototype molecules for applications in medicine and agriculture.

Antifungal Potentiality and Physiological Characterization of Trichoderma Isolates from Port Said Governorate

A TOTAL of twenty Trichoderma isolates belonging to seven species were isolated from several locations at Port Said Governorate. Physiological characteristics of these isolates and their antagonistic effect against Sclerotinia sclerotiorum, the causative agent of white mold of Phaseolus vulgaris were evaluated. Trichoderma polysporum 2 showed the highest activity of total cellulase reached up to 2.95 filter paper unit ml-1. T. harzianum 2 had the highest endoglucanase activity (5.47 IU ml-1), whereas T. polysporum 1 had the highest chitinase activity (1.01 IU ml-1). Siderophores production was assayed using FeCl3, tetrazolium, Arnow’s and spectrophotometric tests. Most of the isolates were able to produce hydroxamate and carboxylate types of siderophores. The ability of Trichoderma to produce indole acetic acid (IAA) and gibberellic acid (GA3) were also investigated. Trichoderma harzianum 2 showed the highest concentration of IAA in broth medium reached up to 13.19μg/ml, whereas T. polysporum 1 showed the highest concentration of GA3 by 586.51μg/ml. The antagonistic potentialities of Trichoderma isolates against Sclerotinia sclerotiorum were tested in vitro by using dual culture, base to base assay and the crude liquid extract effect of the isolates. Percentages of inhibition of radial growth of the pathogen by T. polysporum 1 in dual culture and crude extract methods were 45.97% and 87.78%, respectively. Also, the volatiles of T. piluliferum 2 showed a reduction of the radial growth by 66.85%. So, some Trichoderma isolates collected from Port Said soil showed high biocontrol activity against S. sclerotiorum.

Trichoderma polysporum selectively inhibits white-nose syndrome fungal pathogen Pseudogymnoascus destructans amidst soil microbes

BackgroundPseudogymnoascus destructans (Pd), the causative fungal agent of white-nose syndrome (WNS), has led to the deaths of millions of hibernating bats in the United States of America (USA) and Canada. Efficient strategies are needed to decontaminate Pd from the bat hibernacula to interrupt the disease transmission cycle without affecting the native microbes. Previously, we discovered a novel Trichoderma polysporum (Tp) strain (WPM 39143), which inhibited the growth of Pd in autoclaved soil samples. In the present investigation, we used culture-based approaches to determine Tp-induced killing of native and enriched Pd in the natural soil of two bat hibernacula. We also assessed the impact of Tp treatment on native microbial communities by metagenomics.ResultsOur results demonstrated that Tp at the concentration of 105 conidia/g soil caused 100% killing of native Pd in culture within 5 weeks of incubation. A 10-fold higher concentration of Tp (106 conidia/g soil) killed an enriched Pd population (105 conidia/g soil). The 12,507 fungal operational taxonomic units (OTUs, dominated by Ascomycota and Basidiomycota) and 27,427 bacterial OTUs (dominated by Acidobacteria and Proteobacteria) comprised the native soil microbes of the two bat hibernacula. No significant differences in fungal and bacterial relative abundances were observed between untreated and Tp-treated soil (105Tp conidia/g soil, p ≤ 0.05).ConclusionsOur results suggest that Tp-induced killing of Pd is highly specific, with minimal to no impact on the indigenous microbes present in the soil samples. These findings provide the scientific rationale for the field trials of Tp in the WNS-affected hibernacula for the effective decontamination of Pd and the control of WNS.

Fungal endophytes inhabiting mountain-cultivated ginseng (Panax ginseng Meyer): Diversity and biocontrol activity against ginseng pathogens

Fungal endophytes isolated from mountain-cultivated ginseng (MCG, Panax ginseng Meyer) were explored for their diversity and biocontrol activity against ginseng pathogens (Alternaria panax, Botrytis cinerea, Cylindrocarpon destructans, Pythium sp. and Rhizoctonia solani). A total of 1,300 isolates were isolated from three tissues (root, stem and leaf) from MCGs grown in 24 different geographic locations in Korea. In total, 129 different fungal isolates were authenticated by molecular identification based on internal transcribed spacer (ITS) sequences. The fungal endophytes belonged to Ascomycota (81.7%), Basidiomycota (7.08%), Zygomycota (10%) and Unknown (1.15%), with 59 genera. Analysis of diversity indices across sampling sites suggested species abundance as a function of geographical and environmental factors of the locations. Shannon diversity index and richness in the different tissues revealed that root tissues are colonized more than stem and leaf tissues, and also certain fungal endophytes are tissue specific. Assessment of the ethyl acetate extracts from 129 fungal isolates for their biocontrol activity against 5 ginseng pathogens revealed that Trichoderma polysporum produces the antimcriobial metabolite against all the pathogens. This result indicates the promise of its potential usage as a biocontrol agent.

Communities of fungi in grass silage, corn-cob-mix silage and the whole crop corn silageZbiorowiska grzybów w sianokiszonce, kiszonce z ziarna oraz kiszonce z całych roślin kukurydzy

Summary Corn silage is one of the best roughage, for cattle feeding all year round. A high quality corn silage should be characterized by a pleasant sour smell, unchanged texture and colour of plant fragments, and the absence of pollution by fungi. In 2010 fungi colonizing three types of silage have been identified, with particular emphasis on: Penicillium spp., Aspergillus spp. and Fusarium spp. These three fungi species are known to produce mycotoxins toxic to humans and animals. The analysed substrates were: grass silage, corncob-mix (CCM) silage and the whole crop corn silage. The fungi were isolated most abundantly from the CCM silage and their species composition was most diverse there. In all three types of silage the yeast-like fungi predominated. Aspergillus spp. and Penicillium spp. were isolated most frequently from the CCM silage, whereas they were isolated in small numbers from the grass silage and the whole crop corn silage. Other fungi: Alternaria alternata, Trichoderma polysporum, Cladosporium herbarum, Rhizopus nigricans, Mucor hiemalis, Monascus spp. were isolated sporadically. The fungi of the genus Fusarium were not found in the tested silages.

Synthesis of New VO(II), Co(II), Ni(II) and Cu(II) Complexes with Isatin-3-Chloro-4-Floroaniline and 2-Pyridinecarboxylidene-4-Aminoantipyrine and their Antimicrobial Studies

The complexes of tailor made ligands with life essential metal ions may be an emerging area to answer the problems of multi drug resistance. The coordination complexes of VO(II), Co(II), Ni(II) and Cu(II) with the Schiff bases derived from isatin with 3-chloro-4-floroaniline and 2-pyridinecarboxaldehyde with 4-aminoantipyrine have been synthesized by conventional as well as microwave methods. These compounds have been characterized by elemental analysis, molar conductance, electronic spectra, FT-IR, FAB mass and magnetic susceptibility measurements. FAB mass data show degradation of complexes. Both the ligands behave as bidentate and tridentate coordinating through O and N donor. The complexes exhibit coordination number 4, 5 or 6. The Schiff base and metal complexes show a good activity against the bacteria; Staphylococcus aureus, Escherichia coli and Streptococcus fecalis and fungi Aspergillus niger, Trichoderma polysporum, Candida albicans and Aspergillus flavus. The antimicrobial results also indicate that the metal complexes are better antimicrobial agents as compared to the Schiff bases. The minimum inhibitory concentrations of the metal complexes were found in the range 10~40 μg/mL.

Effects of growing medium on the interactions between biocontrol agents and tomato root pathogens in a closed hydroponic system

SummaryThree commercial biocontrol agents [Trichoderma polysporum plus T. harzianum (Binab T), Gliocladium cantenulatum (Gliomix), and Streptomyces griseoviridis (Mycostop)] were evaluated for their ability to reduce root diseases caused by Pythium aphanidermatum, Phytophthora cryptogea, or Fusarium oxysporum f. sp. radicis-lycopersici in hydroponically-grown tomatoes. Studies were performed using two types of growing medium, peat or pumice, under controlled conditions in a closed irrigation system. The level of disease control varied depending on the biocontrol agent, growing medium, and pathogen. In pumice, amendment with Binab T, Gliomix, or Mycostop reduced the levels and disease incidence of all three pathogens. However, Mycostop had no significant effect on the level of any of the three pathogens in peat, although Binab T and Gliomix both achieved successful biocontrol. In both growth media, biocontrol of F. oxysporum f. sp. radicis-lycopersici was poor compared with that of P. aphanidermatum or P. cryptogea. Overall, tomato plant growth increased after the introduction of any of the biocontrol agents, in the presence of any of the three pathogens, compared with the untreated controls.

Microscopic fungi isolated from the Domica Cave system (Slovak Karst National Park, Slovakia). A review

A broad spectrum, total of 195 microfungal taxa, were isolated from various cave substrates (cave air, cave sediments, bat droppings and/or guano, earthworm casts, isopods and diplopods faeces, mammalian dung, cadavers, vermiculations, insect bodies, plant material, etc.) from the cave system of the Domica Cave (Slovak Karst National Park, Slovakia) using dilution, direct and gravity settling culture plate methods and several isolation media. Penicillium glandicola, Trichoderma polysporum, Oidiodendron cerealis, Mucor spp., Talaromyces flavus and species of the genus Doratomyces were isolated frequently during our study. Estimated microfungal species diversity was compared with literature records from the same substrates published in the past.

Trichoderma-based biological control agents are compatible with the pollinator Bombus terrestris: A laboratory study

The potential value of biofungicides for the control of important plant pathogens, such as the gray mold Botrytis cinerea, requires investigation due to the general requirement for very low pesticide residues in foodstuffs, and concerns over the increasing development of resistance to the different classes of chemical fungicides. Furthermore, the use of bumblebees as pollinators in agriculture and horticulture has become more widespread in recent years, which has generated the need to determine the potential risks of biological control agents against these insects. This study investigated the side-effects of two commercial Trichoderma-based biofungicides against the bumblebee Bombus terrestris. The two commercial compounds tested were Binab-TF-WP and Binab-TF-WP-Konc, both of which contain combinations of Trichoderma harzianum ATCC20476 and Trichoderma polysporum ATCC20475. The bumblebees were exposed to the biocontrol agents under laboratory conditions at their respective maximum concentration in the field (MFRC), and then exposed via three potential routes of exposure: dermal contact, orally via the drinking of treated sugar water, and via treated pollen. The treatments were evaluated through recording worker mortality (lethal effects) and any effects on the production of drones (sublethal effects). The laboratory tests demonstrated that the two Binab products did not cause worker mortality or adversely affect reproduction. In addition, we investigated whether the Trichoderma-based products could survive or grow on the bodies of the adult workers. In no case was survival or growth of the biofungicide observed on the workers. When the effects of these compounds were evaluated against bumblebee larvae (third and fourth instars), no entomopathogenic effects were found. Overall, the results obtained under laboratory conditions indicate that the two Binab products are safe for use in combination with B. terrestris.