Showing papers on "Trichoderma harzianum published in 2014"

Phytohormone Profiles Induced by Trichoderma Isolates Correspond with Their Biocontrol and Plant Growth-Promoting Activity on Melon Plants

Abstract: The application of Trichoderma strains with biocontrol and plant growth-promoting capacities to plant substrates can help reduce the input of chemical pesticides and fertilizers in agriculture. Some Trichoderma isolates can directly affect plant pathogens, but they also are known to influence the phytohormonal network of their host plant, thus leading to an improvement of plant growth and stress tolerance. In this study, we tested whether alterations in the phytohormone signature induced by different Trichoderma isolates correspond with their ability for biocontrol and growth promotion. Four Trichoderma isolates were collected from agricultural soils and were identified as the species Trichoderma harzianum (two isolates), Trichoderma ghanense, and Trichoderma hamatum. Their antagonistic activity against the plant pathogen Fusarium oxysporum f. sp. melonis was tested in vitro, and their plant growth-promoting and biocontrol activity against Fusarium wilt on melon plants was examined in vivo, and compared to that of the commercial strain T. harzianum T-22. Several growth- and defense-related phytohormones were analyzed in the shoots of plants that were root-colonized by the different Trichoderma isolates. An increase in auxin and a decrease in cytokinins and abscisic acid content were induced by the isolates that promoted the plant growth. Principal component analysis (PCA) was used to evaluate the relationship between the plant phenotypic and hormonal variables. PCA pointed to a strong association of auxin induction with plant growth stimulation by Trichoderma. Furthermore, the disease-protectant ability of the Trichoderma strains against F. oxysporum infection seems to be more related to their induced alterations in the content of the hormones abscisic acid, ethylene, and the cytokinin trans-zeatin riboside than to the in vitro antagonism activity against F. oxysporum.

Evaluation of plant growth promoting activities of microbial strains and their effect on growth and yield of chickpea (Cicer arietinum L.) in India

Abstract: The aims of our study were to enhance growth, yield and disease control of chickpea by various combinations of microbial strains ( Mesorhizobium , Azotobacter chroococcum , Pseudomonas aeruginosa and Trichoderma harzianum ). Pseudomonas and Trichoderma showed positive IAA (indole-3-acetic acid) production, phosphate solubilisation and antagonistic activities against Fusarium oxysporum and Rhizoctonia solani as compared to other strains. In two year investigations, tetra-inoculants have shown significant growth attributes, yield and phytopathogen growth inhibition followed by tri-inoculants than control. Therefore, tetra-inoculants ( Mesorhizobium - Azotobacter-Pseudomonas-Trichoderma ) may be used as efficient biofertilizer and bio-control agent for chickpea production ( Cicer arietinum L.) in eastern Uttar Pradesh.

Colonization of onions by endophytic fungi and their impacts on the biology of Thrips tabaci.

Abstract: Endophytic fungi, which live within host plant tissues without causing any visible symptom of infection, are important mutualists that mediate plant–herbivore interactions. Thrips tabaci (Lindeman) is one of the key pests of onion, Allium cepa L., an economically important agricultural crop cultivated worldwide. However, information on endophyte colonization of onions, and their impacts on the biology of thrips feeding on them, is lacking. We tested the colonization of onion plants by selected fungal endophyte isolates using two inoculation methods. The effects of inoculated endophytes on T. tabaci infesting onion were also examined. Seven fungal endophytes used in our study were able to colonize onion plants either by the seed or seedling inoculation methods. Seed inoculation resulted in 1.47 times higher mean percentage post-inoculation recovery of all the endophytes tested as compared to seedling inoculation. Fewer thrips were observed on plants inoculated with Clonostachys rosea ICIPE 707, Trichoderma asperellum M2RT4, Trichoderma atroviride ICIPE 710, Trichoderma harzianum 709, Hypocrea lixii F3ST1 and Fusarium sp. ICIPE 712 isolates as compared to those inoculated with Fusarium sp. ICIPE 717 and the control treatments. Onion plants colonized by C. rosea ICIPE 707, T. asperellum M2RT4, T. atroviride ICIPE 710 and H. lixii F3ST1 had significantly lower feeding punctures as compared to the other treatments. Among the isolates tested, the lowest numbers of eggs were laid by T. tabaci on H. lixii F3ST1 and C. rosea ICIPE 707 inoculated plants. These results extend the knowledge on colonization of onions by fungal endophytes and their effects on Thrips tabaci.

Isolation of Trichoderma and Evaluation of their Antagonistic Potential against Alternaria porri

Abstract: Nine isolates of Trichoderma were collected from Assiut Governorate,Egypt, as leaf surface and endophytic fungi associated with onion florastalks. Four isolates were identified as Trichoderma harzianum, while fiveisolates were belonging to Trichoderma longibrachiatum. The antagonisticactivity of these isolates against onion purple blotch pathogen Alternariaporri was studied in vitro using dual culture assay. All tested Trichodermaisolates showed mycoparasitic activity and competitive capability againstthe mycelial growth of A. porri. Mycoparastic activity of Trichoderma wasmanifested morphologically by the overgrowth upon the mycelial growthof the pathogen and microscopically by production of coiling hyphaearound pathogen hyphae. Isolates of T. harzianum exhibited high abilityto compete on potato dextrose agar (PDA) medium causing the maximumrate of pathogen inhibition (73.12%), while isolates of T. longibrachiatumshowed inhibition rate equalling 70.3%. Chitinase activity of Trichodermawas assayed, and T. harzianum Th-3013 showed the maximum value con-tributing 2.69 U/min. Application of T. harzianum Th-3013 to control pur-ple blotch disease in vivo under greenhouse conditions caused diseasereduction up to 52.3 and 79.9% before and after 48 h of pathogen inocu-lation, respectively, while the fungicide Ridomil Gold Plus caused diseasereduction comprising 56.5 and 71.7%, respectively. This study proved thatT. harzianum Th-3013 as a biocontrol agent showed significant reductionin onion purple blotch disease compared with the tested fungicide.IntroductionPurple blotch disease, caused by Alternaria porri (Ellis)Cif., is one of the most serious diseases that wide-spread in many parts of the world, restricted to Alliumspp. and more prevalent in warm and humid environ-ments (Cramer 2000; Suheri and Price 2000). Purpleblotch disease caused significant reduction in bulband seed yield of the onion crop (Gupta and Pathak1988). The disease is more severe on seed crop ascompared to bulb crop causing sometimes 100% loos-ing of the seed production (Singh et al. 1992;Schwartz 2004). Although chemical control of onionblotch had been practised and its success depends lar-gely on high frequency of spraying, but today, thereare strict regulations on chemical fungicide use due tocarcinogenic effects, residual toxicity problems, envi-ronmental pollution and development of fungicide-resistant strains (Benitez et al. 2004; Rial-Otero et al.2005). Therefore, there are a large number of studiesthat have been devoted to apply a biological control asnature-friendly alternative method (Siameto et al.2010; Soria et al. 2012). The potential of Trichodermaspecies as biocontrol agents of plant diseases was firstrecognized in the early 1930s (Weindling 1932), andsince then, there have been extensive efforts in thecommercial production of them for disease control ina number of crops (Harman 1996; Gardener and Frav-el 2002). Recently, several investigation proved thatTrichoderma have been used to control many foliar

Systemic resistance to gray mold induced in tomato by benzothiadiazole and Trichoderma harzianum T39.

Abstract: Gray mold (Botrytis cinerea) is an important disease of tomato (Solanum lycopersicum). This study examined defense-related gene expression involved in the resistance to B. cinerea that is ...

Identification of mycoparasitism-related genes against the phytopathogen Sclerotinia sclerotiorum through transcriptome and expression profile analysis in Trichoderma harzianum

Abstract: The species of T harzianum are well known for their biocontrol activity against plant pathogens However, few studies have been conducted to further our understanding of its role as a biological control agent against S sclerotiorum, a pathogen involved in several crop diseases around the world In this study, we have used RNA-seq and quantitative real-time PCR (RT-qPCR) techniques in order to explore changes in T harzianum gene expression during growth on cell wall of S sclerotiorum (SSCW) or glucose RT-qPCR was also used to examine genes potentially involved in biocontrol, during confrontation between T harzianum and S sclerotiorum Data obtained from six RNA-seq libraries were aligned onto the T harzianum CBS 22695 reference genome and compared after annotation using the Blast2GO suite A total of 297 differentially expressed genes were found in mycelia grown for 12, 24 and 36 h under the two different conditions: supplemented with glucose or SSCW Functional annotation of these genes identified diverse biological processes and molecular functions required during T harzianum growth on SSCW or glucose We identified various genes of biotechnological value encoding proteins with functions such as transporters, hydrolytic activity, adherence, appressorium development and pathogenesis To validate the expression profile, RT-qPCR was performed using 20 randomly chosen genes RT-qPCR expression profiles were in complete agreement with the RNA-Seq data for 17 of the genes evaluated The other three showed differences at one or two growth times During the confrontation assay, some genes were up-regulated during and after contact, as shown in the presence of SSCW which is commonly used as a model to mimic this interaction The present study is the first initiative to use RNA-seq for identification of differentially expressed genes in T harzianum strain TR274, in response to the phytopathogenic fungus S sclerotiorum It provides insights into the mechanisms of gene expression involved in mycoparasitism of T harzianum against Ssclerotiorum The RNA-seq data presented will facilitate improvement of the annotation of gene models in the draft T harzianum genome and provide important information regarding the transcriptome during this interaction

Salicylic acid prevents Trichoderma harzianum from entering the vascular system of roots

Abstract: Trichoderma is a soil-borne fungal genus that includes species with a significant impact on agriculture and industrial processes. Some Trichoderma strains exert beneficial effects in plants through root colonization, although little is known about how this interaction takes place. To better understand this process, the root colonization of wild-type Arabidopsis and the salicylic acid (SA)-impaired mutant sid2 by a green fluorescent protein (GFP)-marked Trichoderma harzianum strain was followed under confocal microscopy. Trichoderma harzianum GFP22 was able to penetrate the vascular tissue of the sid2 mutant because of the absence of callose deposition in the cell wall of root cells. In addition, a higher colonization of sid2 roots by GFP22 compared with that in Arabidopsis wild-type roots was detected by real-time polymerase chain reaction. These results, together with differences in the expression levels of plant defence genes in the roots of both interactions, support a key role for SA in Trichoderma early root colonization stages. We observed that, without the support of SA, plants were unable to prevent the arrival of the fungus in the vascular system and its spread into aerial parts, leading to later collapse.

Trichoderma: Mass production, formulation, quality control, delivery and its scope in commercialization in India for the management of plant diseases

Abstract: Popularization of biopesticides is very slow as compared to chemicals and only 2% biopesticides are available. Among the different biopesticides, Trichoderma is most exploited and have many success stories. Trichoderma viride and Trichoderma harzianum have curved a niche for themselves in India as important biocontrol agents for management of various diseases. A number of successful products based on different species of Trichoderma have been commercialized in India. The potential Trichoderma isolates are formulated using different organic and inorganic carriers either through solid or liquid fermentation technologies. They are delivered either through seed treatment, bio-priming, seedling dip, soil application, and foliar spray. Application of Trichoderma formulations with strain mixtures perform better than individual strains for the management of pest and diseases of crop plants, in addition to plant growth promotion. Commercialization of the bioproducts is primarily hindered due to the poor shelf life. Hence, research should be concentrated to increase the shelf life of the formulation by developing superior strains that support the increased shelf life, or the organic formulations that support the maximum shelf life with low level of contaminants must be standardized for making biocontrol as a commercial venture. Whatever the limitations these Trichoderma products may have, it can be addressed by enhancing biocontrol through manipulation of the environment, accurate strain identification by molecular approach, using mixtures of beneficial organisms, physiological and genetic enhancement of biocontrol mechanisms, and manipulation of formulations. Of late, many small and large entrepreneurs have entered into the commercial production of bio control agents resulting into the entry of various bio- control products into the world market. Key words: Trichoderma, mass production, formulation, shelf-life, commercialization.

Phylogeny of the Clinically Relevant Species of the Emerging Fungus Trichoderma and Their Antifungal Susceptibilities

Abstract: A set of 73 isolates of the emerging fungus Trichoderma isolated from human and animal clinical specimens were characterized morphologically and molecularly using a multilocus sequence analysis that included the internal transcribed spacer (ITS) regions of the nuclear ribosomal DNA and fragments of the translation elongation factor 1 alpha (Tef1), endochitinase CHI18-5 (Chi18-5), and actin 1 (Act1) genes. The most frequent species was Trichoderma longibrachiatum (26%), followed by Trichoderma citrinoviride (18%), the Hypocrea lixii/Trichoderma harzianum species complex (15%), the newly described species Trichoderma bissettii (12%), and Trichoderma orientale (11%). The most common anatomical sites of isolation in human clinical specimens were the respiratory tract (40%), followed by deep tissue (30%) and superficial tissues (26%), while all the animal-associated isolates were obtained from superficial tissue samples. Susceptibilities of the isolates to eight antifungal drugs in vitro showed mostly high MICs, except for voriconazole and the echinocandins.

Biological control of Fusarium oxysporum f. sp. phaseoli by Trichoderma harzianum and its use for common bean seed treatment

Abstract: Biological control of seed-borne pathogens has shown to enhance germination and physiological quality of seeds. The objectives of this study were to evaluate the in vitro antagonistic effect of five Trichoderma harzianum isolates (CEN287, CEN288, CEN289, CEN290, and CEN316) against Fusarium oxysporum f. sp. phaseoli (Foxy) and test its potential use in seed treatment. Initially, pathogen and antagonists were grown in paired cultures at 25oC, from which samples were assessed using scanning electron microscopy (SEM). Then, clean or Foxy-infected seeds were treated with conidial suspension of the antagonists. Percent of Foxy-infected seeds and normal seedlings were evaluated at seven and nine days of incubation, respectively. All but one Trichoderma isolate (CEN290) inhibited Foxy mycelial growth. SEM analysis revealed that only one Trichoderma isolate (CEN287) showed parasitic interaction with Foxy. Two isolates (CEN287 and CEN316) significantly reduced the Foxy incidence and enhanced seed germination, though less effective than the fungicide mixture (carboxin + thiram). A principal component analysis indicated the importance of volatile metabolites in reducing Foxy incidence on common bean seeds. CEN287 Trichoderma harzianum isolate formed a single group due to its increase in germination rate of Foxyinfected seeds.

Degradation of polyethylene by Trichoderma harzianum —SEM, FTIR, and NMR analyses

Abstract: Trichoderma harzianum was isolated from local dumpsites of Shivamogga District for use in the biodegradation of polyethylene. Soil sample of that dumpsite was used for isolation of T. harzianum. Degradation was carried out using autoclaved, UV-treated, and surface-sterilized polyethylene. Degradation was monitored by observing weight loss and changes in physical structure by scanning electron microscopy, Fourier transform infrared spectroscopy, and nuclear magnetic resonance spectroscopy. T. harzianum was able to degrade treated polyethylene (40 %) more efficiently than autoclaved (23 %) and surface-sterilized polyethylene (13 %). Enzymes responsible for polyethylene degradation were screened from T. harzianum and were identified as laccase and manganese peroxidase. These enzymes were produced in large amount, and their activity was calculated using spectrophotometric method and crude extraction of enzymes was carried out. Molecular weight of laccase was determined as 88 kDa and that of manganese peroxidase was 55 kDa. The capacity of crude enzymes to degrade polyethylene was also determined. By observing these results, we can conclude that this organism may act as solution for the problem caused by polyethylene in nature.

Fusarium oxysporum induces the production of proteins and volatile organic compounds by Trichoderma harzianum T-E5

Abstract: Trichoderma species have been used widely as biocontrol agents for the suppression of soil-borne pathogens. However, some antagonistic mechanisms of Trichoderma are not well characterized. In this study, a series of laboratory experiments were designed to characterize the importance of mycoparasitism, exoenzymes, and volatile organic compounds (VOCs) by Trichoderma harzianum T-E5 for the control of Fusarium oxysporum f. sp. cucumerinum (FOC). We further tested whether these mechanisms were inducible and upregulated in presence of FOC. The results were as follows: T-E5 heavily parasitized FOC by coiling and twisting the entire mycelium of the pathogen in dual cultures. T-E5 growing medium conditioned with deactivated FOC (T2) showed more proteins and higher cell wall-degrading enzyme activities than T1, suggesting that FOC could induce the upregulation of exoenzymes. The presence of deactivated FOC (T2') also resulted in the upregulation of VOCs that five and eight different types T-E5-derived VOCs were identified from T1' and T2', respectively. Further, the excreted VOCs in T2' showed significantly higher antifungal activities against FOC than T1'. In conclusion, mycoparasitism of T-E5 against FOC involved mycelium contact and the production of complex extracellular substances. Together, these data provide clues to help further clarify the interactions between these fungi.

Effect of mycosynthesized silver nanoparticles from filtrate of Trichoderma harzianum against larvae and pupa of dengue vector Aedes aegypti L

Abstract: Mosquitoes transmit dreadful diseases, causing millions of deaths every year. Therefore, screening for larvicidal and pupicidal activity of microbial extracts attributes could lead to development of new and improved mosquito control methods that are economical and safe for nontarget organisms and are ecofriendly. Synthetic chemical insecticides occupy predominant position in control strategies. These hazardous chemicals exert unwarranted toxicity and lethal effects on nontarget organisms, develop physiological resistance in target, and cause adverse environmental effect. For vector control, fungal-mediated natural products have been a priority in this area at present. In the current study, effective larvicidal and pupicidal effect of mycosynthesized silver nanoparticles (Ag NPs) using an entomopathogenic fungi Trichoderma harzianum against developmental stages of the dengue vector Aedes aegypti was investigated. An attractive possibility of green nanotechnology is to use microorganisms in the synthesis of nanosilver especially Ag NPs. The mycosynthesized Ag NPs were characterized to find their unique properties through UV-visible spectrophotometer, X-ray diffraction analysis, Fourier transform infrared, and surface characteristics by scanning electron microscopy. To analyze the bioefficacy, different test concentrations for extracellular filtrate (0.2, 0.4, 0.6, 0.8, and 1.0 %) and Ag NPs (0.05, 0.10, 0.15, 0.20, and 0.25 %) were prepared to a final volume of 200 mL using deionized water; 20 larvae of each instars (I–IV) and pupa were exposed to each test concentration separately which included a set of control (distilled water) group with five replicates. Characterization of the synthesized Ag NPs were about 10–20 nm without aggregation. Susceptibility of larval instars to synthesized Ag NPs was higher than the extracellular filtrate of T. harzianum alone after 24-h exposure, where the highest mortality was recorded as 92 and 96 % for first and second instars and 100 % for third, fourth instars, and pupa. Lethal concentration 50 values of 0.079, 0.084, 0.087, 0.068, and 0.026 % were recorded for I–IV instars and pupa, respectively, when exposed to Ag NPs at 0.25 % concentration. Toxicity was exhibited against first (1.076 %), second (0.912 %), third (0.770 %), fourth (0.914 %) instars larvae, and pupa (0.387 %) with extracellular filtrate at a concentration of 1 % that was three- to fourfold higher compared to Ag NPs; no mortality was observed in the control. The present study is the first report on effective larvicidal and pupicidal activity of Ag NPs synthesized from an entomopathogenic fungi T. harzianum extracellular filtrate and could be an ideal ecofriendly, single-step, and inexpensive approach for the control of A. aegypti.

Status of Trichoderma research in India: A review

Abstract: Species of Trichoderma are diverse fungal microbial community known and explored worldwide for their versatilities as biocontrol and growth promoting agents. They are also widely exploited in industries as sources of enzymes. A large number of research groups are working on various aspects of Trichoderma viz., diversity, ecology and their applications. In India, about 110 groups representing various universities and research institutes are working with about 15 different species and have published about 460 research papers. Trichoderma harzianum and Trichoderma viride are the widely used species and have been exploited on about 87 different crops and about 70 soilborne and 18 foliar pathogens, respectively. This review aims to give an overview of the status of usage of Trichoderma on important agricultural crops by different groups and organizations in the country.

Analysis of Phaseolus vulgaris response to its association with Trichoderma harzianum (ALL-42) in the presence or absence of the phytopathogenic fungi Rhizoctonia solani and Fusarium solani.

Abstract: The present study was carried out to evaluate the ability of Trichoderma harzianum (ALL 42-isolated from Brazilian Cerrado soil) to promote common bean growth and to modulate its metabolism and defense response in the presence or absence of the phytopathogenic fungi Rhizoctonia solani and Fusarium solani using a proteomic approach. T. harzianum was able to promote common bean plants growth as shown by the increase in root/foliar areas and by size in comparison to plants grown in its absence. The interaction was shown to modulate the expression of defense-related genes (Glu1, pod3 and lox1) in roots of P. vulgaris. Proteomic maps constructed using roots and leaves of plants challenged or unchallenged by T. harzianum and phytopathogenic fungi showed differences. Reference gels presented differences in spot distribution (absence/presence) and relative volumes of common spots (up or down-regulation). Differential spots were identified by peptide fingerprinting MALDI-TOF mass spectrometry. A total of 48 identified spots (19 for leaves and 29 for roots) were grouped into protein functional classes. For leaves, 33%, 22% and 11% of the identified proteins were categorized as pertaining to the groups: metabolism, defense response and oxidative stress response, respectively. For roots, 17.2%, 24.1% and 10.3% of the identified proteins were categorized as pertaining to the groups: metabolism, defense response and oxidative stress response, respectively.

Mycoparasitism studies of Trichoderma harzianum against Sclerotinia sclerotiorum : evaluation of antagonism and expression of cell wall-degrading enzymes genes

Abstract: Trichoderma spp. are known for their biocontrol activity against several plant pathogens. A specific isolate of Trichoderma harzianum, 303/02, has the potential to inhibit the growth of Sclerotinia sclerotiorum, an important agent involved in several crop diseases. In this study, the interaction between T. harzianum 303/02 and mycelia, sclerotia and apothecia of S. sclerotiorum was studied by scanning electron microscopy. RT-qPCR was used to examine the expression of 11 genes potentially involved in biocontrol. T. harzianum 303/02 parasitizes S. sclerotiorum by forming branches that coil around the hyphae. The fungus multiplied abundantly at the sclerotia and apothecia surface, forming a dense mycelium that penetrated the inner surface of these structures. The levels of gene expression varied according to the type of structure with which T. harzianum was interacting. The data also showed the presence of synergistic action between the cell-wall degrading enzymes.

Saccharification of rice straw by cellulase from a local Trichoderma harzianum SNRS3 for biobutanol production.

Abstract: Rice straw has shown to be a promising agricultural by-product in the bioconversion of biomass to value-added products. Hydrolysis of cellulose, a main constituent of lignocellulosic biomass, is a requirement for fermentable sugar production and its subsequent bioconversion to biofuels such as biobutanol. The high cost of commercial enzymes is a major impediment to the industrial application of cellulases. Therefore, the use of local microbial enzymes has been suggested. Trichoderma harzianum strains are potential CMCase and β-glucosidase producers. However, few researches have been reported on cellulase production by T. harzianum and the subsequent use of the crude cellulase for cellulose enzymatic hydrolysis. For cellulose hydrolysis to be efficiently performed, the presence of the whole set of cellulase components including exoglucanase, endoglucanase, and β-glucosidase at a considerable concentration is required. Biomass recalcitrance is also a bottleneck in the bioconversion of agricultural residues to value-added products. An effective pretreatment could be of central significance in the bioconversion of biomass to biofuels. Rice straw pretreated using various concentrations of NaOH was subjected to enzymatic hydrolysis. The saccharification of rice straw pretreated with 2% (w/v) NaOH using crude cellulase from local T. harzianum SNRS3 resulted in the production of 29.87 g/L reducing sugar and a yield of 0.6 g/g substrate. The use of rice straw hydrolysate as carbon source for biobutanol fermentation by Clostridium acetobutylicum ATCC 824 resulted in an ABE yield, ABE productivity, and biobutanol yield of 0.27 g/g glucose, 0.04 g/L/h and 0.16 g/g glucose, respectively. As a potential β-glucosidase producer, T. harzianum SNRS3 used in this study was able to produce β-glucosidase at the activity of 173.71 U/g substrate. However, for cellulose hydrolysis to be efficient, Filter Paper Activity at a considerable concentration is also required to initiate the hydrolytic reaction. According to the results of our study, FPase is a major component of cellulose hydrolytic enzyme complex system and the reducing sugar rate-limiting enzyme. Our study revealed that rice straw hydrolysate served as a potential substrate for biobutanol production and FPase is a rate-limiting enzyme in saccharification.

Application of benzothiadiazole and Trichoderma harzianum to control faba bean chocolate spot disease and their effect on some physiological and biochemical traits

Abstract: Chocolate spot disease is the most prevalent and important disease in the major faba bean growing regions in the world. Different concentrations of the abiotic inducer (0.3 and 0.5 mM benzothiadiazole) and the biotic inducer (1 × 107 and 2 × 107 spore/ml Trichoderma harzianum) were used alone or in combination to study their efficiency against faba bean chocolate spot disease caused by Botrytis fabae and Botrytis cinerea and their effect on some chemical analyses (phenylalanine ammonia lyase activity, total flavonoids and peroxidase isozymes, pectin and lignin content and total chlorophyll content). Application of the tested inducers as foliar treatment significantly reduced the severity of chocolate spot disease as compared with untreated infected plants. The reduction in disease severity was associated with a gradual increase in phenylalanine ammonia lyase activity. Maximum increase was recorded at 72 h after inoculation with B. fabae and B. cinerea. In addition, the levels of flavonoids in induced infected leaves recorded a sharp increase at 24 h after inoculation with B. fabae or B. cinerea. Also, pectin and lignin contents in the cell wall of induced infected plants were significantly increased as compared with untreated infected plants. Beside the induction of resistance, the tested inducers markedly increased total chlorophyll content in treated infected plants as compared with untreated infected plants. Isozymes analysis revealed that new peroxidase bands were induced only in treated faba bean leaves in response to infection with B. fabae or B. cinerea.

Trichoderma harzianum elicits induced resistance in sunflower challenged by Rhizoctonia solani

Abstract: Aims To investigate the efficacy of Trichoderma harzianum NBRI-1055 (denoted as ‘T-1055’) in suppression of seedling blight of sunflower caused by Rhizoctonia solani Kuhn and their impact on host defence responses. Methods and Results T-1055 was applied as seed treatment, soil application and combined application (seed treatment + soil application). Higher protection afforded by combined application of T-1055 was associated with the marked induction of phenylalanine ammonia-lyase (PAL), polyphenol oxidase (PPO), peroxidase (PO) and cinnamyl alcohol dehydrogenase (CAD) activities. The activities of PAL and PPO reached maximum at 10 days after sowing (DAS), while PO and CAD levels reached maximum at 12 DAS. This was further supported by the accumulation of total phenolic content that showed an increase up to threefold at 14 DAS. In addition, HPLC analysis revealed that the contents of ferulic and p-coumaric acids increased by 6·3 and 4·6 times, respectively, at 14 DAS. Amount of gallic acid was also little more than double. Lignin deposition in sunflower root increased by 2·7, 3·4 and 3·7 times through combined application of T-1055 at 16, 18 and 20 DAS, respectively. Combined application also increased the accumulation of PR-2 and PR-3 proteins by 3·3 and 3·9 times, respectively, at 12 DAS in followed by seed treatment alone. Conclusions The combined application of T-1055 triggered defence responses in an enhanced level in sunflower than the soil and seed alone and provided better protection against Rhizoctonia seedling blight. Significance and Impact of the Study Rhizospheric fungal bioagent ‘T-1055’ can enhance protection in sunflower against the R. solani pathogen through augmented elicitation of host defence responses.

Nanoparticle-enhanced electrochemical biosensor with DNA immobilization and hybridization of trichoderma harzianum gene

Abstract: The genus Trichoderma is a soil-borne fungi which in numerous reports has been successfully used as a biological control agent against various plant pathogens. The identification of Trichoderma species worldwide is currently deduced from micro-morphological descriptions which are tedious and prone to error. Electrochemical approaches are currently being developed for the detection and analysis of DNA. In the present study, an electrochemical DNA biosensor was successfully developed based on ionic liquid (e.g., 1-ethyl-3-methylimidazolium trifluoromethanesulfonate ([EMIM][Otf])), ZnO nanoparticles and a chitosan (CHIT) nanocomposite membrane on a modified gold electrode (AuE). A single-stranded DNA probe was immobilized on this electrode. Methylene blue (MB) was used as the hybridization indicator to monitor the hybridization reaction of the target DNA. Under optimal conditions using differential pulse voltammetry (DPV), the target DNA sequences were detectable at concentration ranges of 1.0 A— 10−18–1.82 A— 10−4 mol L−1, and the detectable limit was 1.0 A— 10−19 mol L−1. The developed DNA biosensor enables the study of hybridization with crude DNA fragments and the results of this study confirm that this DNA biosensor provides a fast, sensitive and convenient way for the species level identification of Trichoderma harzianum.

Antimicrobial activity of Trichoderma harzianum against bacteria and fungi

Abstract: Trichoderma is a genus of fungi that is present in all soils, where they are the most prevalent culturable fungi. Many species in this genus can be characterized as opportunistic avirulent plant symbionts. Cultures are typically fast growing at 2530°C, but will not grow at 35°C. Colonies are transparent at first on media such as cornmeal dextrose agar (CMD) or white on richer media such as potato dextrose agar (PDA). Some species produce a characteristic sweet or coconut odour (Aneja, 2003). Trichoderma harzianum is a common soil, litter, and wood fungus. It possesses highly cellulolytic activity and is main agents of decomposition. Several strains of Trichoderma have been developed as biocontrol agents against fungal diseases of plants. The various mechanisms include antibiosis, parasitism, inducing host-plant resistance, and competition. Most biocontrol agents are ISSN: 2319-7706 Volume 3 Number 1 (2014) pp. 96-103 http://www.ijcmas.com

Immobilization of Trichoderma harzianum α-amylase on treated wool: optimization and characterization.

Abstract: α-Amylase from Trichoderma harzianum was covalently immobilized on activated wool by cyanuric chloride. Immobilized α-amylase exhibited 75% of its initial activity after 10 runs. The soluble and immobilized α-amylases exhibited maximum activity at pH values 6.0 and 6.5, respectively. The immobilized enzyme was more thermally stable than the soluble one. Various substrates were hydrolyzed by immobilized α-amylase with high efficiencies compared to those of soluble α-amylase. The inhibition of the immobilized α-amylase by metal ions was low as compared with soluble enzyme. On the basis of the results obtained, immobilized α-amylase could be employed in the saccharification of starch processing.

Transcriptome Profile of Trichoderma harzianum IOC-3844 Induced by Sugarcane Bagasse

Abstract: Profiling the transcriptome that underlies biomass degradation by the fungus Trichoderma harzianum allows the identification of gene sequences with potential application in enzymatic hydrolysis processing. In the present study, the transcriptome of T. harzianum IOC-3844 was analyzed using RNA-seq technology. The sequencing generated 14.7 Gbp for downstream analyses. De novo assembly resulted in 32,396 contigs, which were submitted for identification and classified according to their identities. This analysis allowed us to define a principal set of T. harzianum genes that are involved in the degradation of cellulose and hemicellulose and the accessory genes that are involved in the depolymerization of biomass. An additional analysis of expression levels identified a set of carbohydrate-active enzymes that are upregulated under different conditions. The present study provides valuable information for future studies on biomass degradation and contributes to a better understanding of the role of the genes that are involved in this process.

Trichoderma harzianum t22 induces in maize systemic resistance against fusarium verticillioides

Abstract: SUMMARY Fusarium verticillioides is one of the most common plant pathogenic fungi affecting maize causing ear and kernel rot. Nearly the totality of the fungal strains are able to produce mycotoxins known as fumonisins at very different levels. However, information on the ability of the biocontrol fungus Trichoderma harzianum to induce systemic resistance in maize against F. verticillioides is still lacking. We now show that, upon root colonization by T. harzianum, F. verticillioides consistently reduces maize disease symptoms. The enhanced activation of SA- and JA/ ET-dependent defence responses indicates that resistance in maize is caused by a better perception of the fungal pathogen due to the effect of Trichoderma inocula. Seed biopriming with T. harzianum could be a useful strategy to control F. verticillioides infection and fumonisin accumulation under field conditions.

Characterization of resistance mechanisms activated by Trichoderma harzianum T39 and benzothiadiazole to downy mildew in different grapevine cultivars

Abstract: Downy mildew, caused by Plasmopara viticola, is one of the most destructive diseases of grapevine and is controlled with intense application of chemical fungicides. Treatment with Trichoderma harzianum T39 (T39) or benzothiadiazole-7-carbothioic acid S-methyl ester (BTH) has been previously shown to activate grapevine resistance to downy mildew and reduce disease symptoms in the Pinot noir cultivar. However, enhancement of plant resistance can be affected by several factors, including plant genotype. In order to further extend the use of resistance inducers against downy mildew, the physiological and molecular properties of T39- and BTH-activated resistance in different cultivars of table and wine grapes were characterized under greenhouse conditions. T39 treatment reduced downy mildew symptoms, but the degree of efficacy differed significantly among grapevine cultivars. However, efficacy of BTH-activated resistance was consistently high in the different cultivars. Expression profiles of defence-related genes differed among cultivars in response to resistance inducers and to pathogen inoculation. T39 treatment enhanced the expression of defence-related genes in the responsive cultivars, before and after P. viticola inoculation. A positive correlation between the efficacy of T39 and the expression level of defence-related genes was found in Primitivo and Pinot noir plants, while different genes or more complex processes were probably activated in Sugraone and Negroamaro. The data reported here suggest that the use of a responsive cultivar is particularly important to maximize the efficacy of resistance inducers and new natural inducers should be explored for the less responsive cultivars.