Biocontrol efficacy of Trichoderma spp. against sesame wilt caused by Fusarium oxysporum f. sp. sesami

Sesame (Sesamum indicum L.) is one of the most important oilseed crops in Egypt and worldwide. It is being infected with many pathogens, among these pathogens Fusarium oxysporum f.sp. sesami (Zap.) Cast is causing severe economic losses on sesame. In this study, antagonistic capability of 24 isolates of Trichoderma spp. was assessed in vitro against F. oxysporum f.sp. sesami. Two strains; T. harzianum (T9) and T. viride (T21) were revealed to have high antagonistic effect against F. oxysporum f.sp. sesami in vitro with inhibition percentage about 70 and 67%, respectively. These two isolates proved to have high ability to control Fusarium wilt disease under greenhouse conditions. The highest reduction in disease severity was achieved with T. viride followed by T. harzianum with reduction in disease severity about 77 and 74%, respectively. This study revealed that the time of application of bioagents is a decisive factor in determining the efficacy of Trichoderma isolates to control Fusarium wilt of sesame. It was revealed that the highest reduction in the disease severity was achieved when either Trichoderma viride or T. harzianum were applied 7 days before challenging with the F. oxysporum f.sp. sesami.     

Antagonistic assessment of Trichoderma spp. by producing volatile and non-volatile compounds against different fungal pathogens

Trichoderma spp. are well-known biological agents that have significant antagonistic activity against several plant pathogenic fungi. In the present study, Trichoderma spp. were tested in vitro for their antagonistic activity against different spp. of Fusarium and Alternaria viz. Alternaria alternata, A. brassicae, A. solani, Fusarium oxysporum and F. solani using dual plate assay and by the production of volatile and non-volatile compounds. The results obtained revealed that Trichoderma harzianum and T. viride effectively inhibited the growth and spore production of different spp. of Fusarium and Alternaria. The highest growth inhibition was found in A. alternata 62.50% and 60.00% by non-volatile compounds of T. harzianum and T. viride, respectively. Similarly, the volatile compounds inhibit the maximum growth of A. alternata 40.00% and 35.00% by T. harzianum and T. viride, respectively. Volatile and non-volatile compounds of Trichoderma spp. were analysed by GC-MS technique and the properties of distinguished compounds showed antifungal, antimicrobial and antibiotic activities. Volatile compounds of T. harzianum and T. viride showed highest percent abundance for glacial acetic acid (45.32%) and propyl-benzene (41.75%), respectively. In case of non-volatile compounds, T. harzianum and T. viride showed D-Glucose, 6-O-α-D-galactopyranosyl- (38.45%) and 17-Octadecynoic acid (36.23%), respectively. The results of present study confirmed that T. harzianum can be used as a promising biological control agent against Alternaria and Fusarium spp. that cause diseases in various vegetables and crops.     

Biocontrol potential of Trichoderma species against mango malformation pathogens

Malformation disease of Mango (Mangifera indica L.) caused by Fusarium moniliforme var. subglutinans is one of the most destructive diseases, which is a major production constraint in the mango-growing regions of India. In this study, The bioagents Trichoderma viride (Tr1), Trichoderma virens (Tr2) and Trichoderma harzianum (Tr3) were evaluated in culture with the pathogens to monitor the antagonistic effect and their volatile compound and culture filtrates (non-volatile compound). It was found that all the three isolates of bioagents significantly checked the growth of F. moniliforme var. subglutinans. In dual culture, the best result was obtained with T. harzianum followed by T. virens and T. viride. A similar result was also observed in the case of culture filtrates ofTrichoderma spp. The results clearly showed that inhibition of the growth of the fusaria isolates by T. harzianum was significantly superior to T. viride andT.virens. In case of antifungal activity of volatile compounds released by Trichoderma isolates, it was also observed that T. virens was more superior to T.harzianum and T. viride.     

Antagonistic activity and hyphal interactions of Trichoderma spp. against Fusarium proliferatum and F. oxysporum in vitro

Trichoderma is a well-known antagonist against soilborne plant pathogens. However, the species and even various isolates have different biocontrol potential. To evaluate the antagonistic activities of Trichoderma harzianum, T. harzianum strain T100 (T100), T. viride and T. haematum against Fusarium oxysporum and F. proliferatum, we used dual culture and productions of volatile and non-volatile metabolites in three different phases in vitro. An analysis of the data in dual culture tests represented T. viride, T. haematum and T100 as effective antagonists of Fusarium while T100 was the only fungus being able to lyse the confronting mycelia. Similar results were obtained in the volatile metabolites tests also. In contrast with the two previous tests, the non-volatile metabolites produced by T. harzianum inhibited Fusarium mycelial growth the most, and T100 acted moderately. It was also clearly showed that the antagonistic effect of Trichoderma spp. was more on F. proliferatum than on F. oxysporum. Finally, because Trichoderma spp. was most effective in the second phase, we recommend to use T100 against F. proliferatum at the initial stages of infection as its mycoparasitism on F. oxysporum was observed microscopically through forming apressoria structures without any coiling around the pathogen.     

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

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 species on Agaricus bisporus farms in Serbia and their biocontrol

Twenty Trichoderma isolates were collected on 13 Serbian Agaricus bisporus farms and one in Bosnia and Herzegovina during 2006–2010. Twelve isolates were classified into five species by standard mycological studies and ITS1/ITS4 sequence analyses, namely Trichoderma atroviride, Trichoderma koningii, Trichoderma virens, Trichoderma aggressivum f. europaeum and Trichoderma harzianum. Eight isolates were not identified to the species level but were shown to be related to T. harzianum. The isolates of T. harzianum exhibited the highest virulence to the harvested A. bisporus pilei and T. virens and T. aggressivum f. europaeum the lowest. Antifungal activity of two biofungicides based on Bacillus subtilis and tea tree oil and the fungicide prochloraz manganese were tested in vitro to all Trichoderma isolates. Prochloraz manganese and B. subtilis were highly toxic to all tested Trichoderma isolates, their ED₅₀ values were below 0.3 and 1.3 mg L^?1, respectively. Tea tree oil did not exhibit a significant antifungal activity (ED₅₀ = 11.9–370.8 mg L^?1). The effectiveness of biofungicides was evaluated against T. harzianum in a mushroom growing room, and they were applied alone or in combination with the fungicide at a respective proportion of 20:80%. Prochloraz manganese showed higher effectiveness than both tested biofungicides or their respective mixtures. The biofungicide based on B. subtilis demonstrated greater effectiveness in preventing disease symptoms than tea tree oil. B. subtilis combined with the fungicide revealed less antagonism in effectiveness against pathogen than tea tree oil.     

Wyerone Acid Phytoalexin Synthesis and Peroxidase Activity as Markers for Resistance of Broad Beans to Chocolate Spot Disease

Infection of broad bean (Vicia faba L.) leaves with Botrytis fabae (Sard.) resulted in wyerone acid phytoalexin accumulation and increase in peroxidase activities in resistant and susceptible broad bean cultivars. Rapid wyerone acid accumulation was observed in leaves of resistant cultivars that reached levels greater than twofold of the susceptible cultivars. Following infection of broad bean cultivars, either resistant or susceptible to B. fabae, wyerone acid synthesis in resistant cultivars peaked at 5 days then declined, whereas in susceptible cultivars synthesis gradually decreased. While the ethanol‐extract of wyerone acid significantly reduced B. fabae spore germination with increased concentrations, the phytoalexin had no effect on in vitro B. fabae germ‐tube growth. Peroxidase activity in infected leaves of resistant was 10 times higher than the susceptible cultivars and eight times higher in uninfected leaves of the resistant than the susceptible cultivars. Peroxidase activity in infected leaves was greater than twofold in resistant cultivars and less than twofold in susceptible cultivars, when compared with uninfected leaves. The ratio of peroxidase activity in infected to uninfected leaves increased over time in susceptible cultivars but remained unchanged in resistant cultivars. Peroxidase activity in uninfected and infected leaves and wyerone acid biosynthesis in infected broad bean plants were successfully used to ascertain the resistance and susceptibility of four broad bean cultivars to B. fabae. Using wyerone acid synthesis and peroxidase activity as preliminary markers for resistance of broad bean to chocolate spot disease, caused by B. fabae, is suggested in this study.     

Biocontrol of onion white rot by application of Trichoderma species formulated on wheat bran powder

In vitro, Trichoderma album, Trichoderma harzianum, Trichoderma koningii, Trichoderma viride and Trichoderma virens showed antagonistic effect against the most pathogenic isolate (Sc2) of Sclerotium cepivorum, the cause of onion white rot disease. Five Trichoderma preparations of each Trichoderma sp. were prepared on wheat bran powder to be used for controlling white rot disease of onion. Greenhouse and field experiments followed the same trend where T. harzianum and T. koningii were the most effective in reducing the incidence and severity of white rot disease compared with the control. Trichoderma species preparations caused promotion to vegetative parameters of onion plants in pots and increase bulb productivity in filed. In this regard, T. harzianum and T. koningii were the most effective. A positive correlation was found between the biocontrol activity of Trichoderma species preparations and enhancement of peroxidase, polyphenoloxidase and chitinase enzymes in onion plants to resist infection with S. cepivorum.     

Potential for Biocontrol of Lasiodiplodia theobromae (Pat.) Griff. & Maubl. in Banana Fruits by Trichoderma Species

Fifteen Trichoderma isolates were tested for their antagonistic ability against Lasiodiplodia theobromae. Trichoderma harzianum exhibited the greatest inhibition in dual culture. Microscopic investigation demonstrated direct parasitism and coiling of T. harzianum and T. viride around hyphae of L. theobromae, causing swollen, deformed, shortened, or rounded cells of the pathogen. Granulation of cytoplasm and disintegration of the hyphal walls of L. theobromae also were noted in dual culture. Trichoderma viride reduced rotting by 29.07 to 65.06% in artificially inoculated banana fruits. Treatment of banana fruits with T. viride 4 h prior to inoculation with L. theobromae provided better protection than simultaneous application or treatment 4 h after inoculation.     

Efficacy ofTrichoderma chitinases againstRhizoctonia solani, the rice sheath blight pathogen

Thirty-five strains ofTrichoderma viride andT. harzianum were screened for their antagonistic ability against the rice sheath blight pathogen,Rhizoctonia solani. The strains that inhibited/overgrew the phytopathogenic fungus were considered effective. Light microscopic studies showed the antagonism of the hyphae of effectiveTrichoderma strains towards their host hyphae. Chitinase activity ofTrichoderma culture filtrates was enhanced, when colloidal chitin was used as the sole carbon source, instead of glucose. Chitinase pattern differed among the four select strains. The chitinase isoforms are induced differentially by carbon sources. The chitin affinity column fraction ofTrichoderma culture filtrate inhibited,in vitro, the growth ofR. solani.     

Evaluating the promise of Trichoderma and Anabaena based biofilms as multifunctional agents in Macrophomina phaseolina-infected cotton crop

The influence of biofilmed formulations composed of Trichoderma viride and Anabaena torulosa as matrices was investigated in Macrophomina phaseolina (Tassi) Goid.-infected cotton crop, in terms of plant growth and biocontrol parameters. Trichoderma based biofilms were developed with Azotobacter chroococcum, Pseudomonas fluorescens and Bacillus subtilis, while A. torulosa biofilms were prepared using B. subtilis and T. viride as components. Scanning electron microscopy revealed significant colonisation of biofilms on the root surface, which could be correlated with lowest mortality of 5.67%, recorded using T. viride–B. subtilis biofilm. An increase of 4–7% in polyphenol oxidase enzyme activity was recorded in all biofilm-treated samples, particularly those in which B. subtilis was present. The highest value of 1360.22 µg microbial biomass carbon g^?1 soil was recorded in Anabaena–B. subtilis biofilm treatment. Significantly higher values of plant and soil nutrient parameters in treatments in which biofilms were used vis-à-vis individual cultures reveal their promise. Such novel biofilmed biofertilizers with multiple useful traits can be beneficial options for effective nutrient and pest management of cotton crop.     

Fusant Trichoderma HF9 with enhanced extracellular chitinase and protein content

Strain improvement was carried out to obtain higher chitinase and protein by inter-specific protoplast fusion between Trichoderma harzianum and Trichoderma viride. Fusant HF9 and parental strains of Trichoderma were compared for chitinase and protein production. 1% of glucose, sucrose and fungal cell wall (Rhizoctonia solani), were used as carbon source for cultivation of Trichoderma and fungal cell wall was the best to induce chitinase and protein. Usage of 0.5% colloidal chitin for the fungal growth under aerated conditions at pH 6.5 and 28°C led to higher chitinase and protein production. In these conditions fusant Trichoderma HF9 in comparison with parent strains had 3-, 2.5- and 1.5-fold increase of total chitinase, specific chitinase and protein, respectively. SDS-PAGE analysis revealed that it had 9 major protein bands with up-regulation compared to parent strains. Amino acid analysis showed that protein of culture filtrate of T. harzianum, T. viride and fusant Trichoderma HF9 had 8, 6 and 10 amino acids, respectively. The results obtained suggested that fusant HF9 could be an integration of T. harzianum and T. viride through protoplast fusion.     

Management of postharvest disease of mango anthracnose incited by Colletotrichum gleosporioides

Abstract

Among the seven fungal (Gliocladium virens, Trichoderma hamatum, T. harzianum, T. koningii, T. longibrachiatum, T. pseudokoningii and T. viride) and two bacterial (Bacillus subtilis and Pseudomonas fluorescens) antagonists screened against C. gloeosporioides under in vitro conditions, T. harzianum exhibited maximum inhibition followed by Pseudomonas fluorescens at 5 days after incubation. These fungal and bacterial antagonists were selected for application to fruits infected with pathogens. Fruits inoculated with C. gloeosporioides were dipped in spore/cell suspensions of fungal/bacterial antagonists and kept for different durations. The fungal antagonists T. harzianum and P. fluorescens were effective in checking the spread of pathogens on fruits compared with the pathogen-inoculated control.     

Biocontrol of yellow disease of Brassica campestris caused by Fusarium oxysporum with Trichoderma viride under field conditions

Trichoderma viride was selected from three species of Trichoderma and was applied to the soil for biocontrol of yellow disease of Brassica campestris caused by Fusarium oxysporum. The population density of F. oxysporum averaged 10³ to 10⁴ cfu/g of soil in eight greenhouses. Moreover, the results of application of T. viride showed that the yellow disease of the first, second, and third crops in greenhouse A was 33%, 48%, and 35% in control plot, while it was 1.4%, 11.5%, and 3.0% in T. viride plots, respectively. Also in greenhouse B, the yellow disease of the first crop was inhibited by T. viride compared with control. However, the suppressive effect of T. viride declined on the second crop. Therefore, the third crop was not cultured in greenhouse B. The population density of T. viride in greenhouse A, in which yellow disease was successfully controlled, was higher than that in greenhouse B.     

Ecological management of tropical sugar beet (TSB) root rot (Sclerotium rolfsii (Sacc.) by rhizosphere Trichoderma species

Trichoderma species are collected from different location of sugarbeet growing areas of Tamil Nadu and it is effective against Sclerotium rolfsii pathogen caused by sugarbeet ecosystems. Out of thirty-one isolates of Trichoderma viride and four isolates of Trichoderma harzianum collected and tested for their antagonistic activity against S. rolfsii by dual culture technique, one isolate was found to be effective T. viride (TVB1) that recorded the maximum (73.03%) inhibition on the mycelial growth recording only 2.40 cm growth as against 8.90 cm in the control. The isolates of T. harzianum THB-1 recorded 71.19% mycelial growth reduction over control. The colonisation behaviour of T. viride (TVB1) revealed that it completely over grew on pathogen within 48 h after interaction with the pathogen, and speed of growth on pathogen was also high and it possesses a higher level of competitive saprophytic ability. The best four isolates of TVB1, TVB-2, TVB-3 and TVB31 and two isolates of T. harzianum THB-1 and THB-2 were compared with other species of Trichoderma longibrachiatum, Trichoderma reesei, Trichoderma koningii and Chaetomium globosum and tested under in vitro condition. BA of neem cake at 150 kg ha^?1 + T. viride isolate (TVB1) at 2.5 kg/ha recorded least root rot disease incidence of 17.05% which accounted for 75.37% disease reduction over control and highest recorded maximum root yield 65.73 t ha^?1 and increasing sugar content.     

<i>Trichoderma</i>-Induced Improvement in Growth,Photosynthetic Pigments,Proline, and Glutathione Levels in <i>Cucurbita pepo</i> Seedlings under Salt Stress

Salt stress is one of the major abiotic stress in plants. However, traditional approaches are not always efficient in conferring salt tolerance. Experiments were conducted to understand the role of Trichoderma spp. (T. harzianum and T. viride) in growth, chlorophyll (Chl) synthesis, and proline accumulation of C. pepo exposed to salinity stress. There were three salt stress (50, 100, and 150 mM NaCl) lavels and three different Trichoderma inoculation viz. T. harzianum, T. viride, and T. harzianum + T. viride. Salt stress significantly declined the growth in terms of the shoot and root lengths; however, it was improved by the inoculation of Trichoderma spp. C. pepo inoculated with Trichoderma exhibited increased synthesis of pigments like chl a, chl b, carotenoids, and anthocyanins under normal conditions. It was interesting to observe that such positive effects were maintained under salt-stressed conditions, as reflected by the amelioration of the salinity-mediated decline in growth, physiology and antioxidant defense. The inoculation of Trichoderma spp. enhanced the synthesis of proline, glutathione, proteins and increased the relative water content. In addition, Trichoderma inoculation increased membrane stability and reduced the generation of hydrogen peroxide. Therefore, Trichoderma spp. can be exploited either individually or in combination to enhance the growth and physiology of C. pepo under saline conditions.     

Mycoparasitism of Trichoderma spp. in biocontrol of fusarial wilt of tomato

Wilt of tomato caused by Fusarium oxysporum is one of the most serious diseases posing a threat to its cultivation. As such a thorough search was made to evaluate the mycoparasitic potentiality of three species of Trichoderma, T. harzianum, T. viride and T. hamatum towards minimising the effect of the pathogen on ravages of the crop. All the experimental species of Trichoderma were able to produce lytic enzymes, β-1,3 glucanase and chitinase efficiently but their activity could be hastened up in the presence of cell wall material of the pathogen where T. harzianum was recorded to be the best in rank. Lysis of mycelium of the pathogen was achieved by treatment with metabolic filtrate of the antagonistic fungi. SEM micrographs correspondingly showed lysis of pathogenic mycelium due to overgrowth and penetration through hyphal pegs and coiling produced by T. harzianum. Application of the antagonistic fungi in the field showed their ability to reduce the incidence of the wilt disease to a reasonable extent where the performance of T. harzianum happened to be superior over the others.     

Control of the bean rust fungus <Emphasis Type="Italic">Uromyces appendiculatus</Emphasis> by means of <Emphasis Type="Italic">Trichoderma harzianum</Emphasis>: leaf disc assays on the antibiotic effect of spore suspensions and culture filtrates

Several species of the fungal genus Trichoderma act as antagonists of other fungi. A number of strains from the Trichoderma species T. harzianum Rifai are used as biological control agents for the control of soilborne as well as foliar plant pathogens. Six T. harzianum strains, five of them isolated from commercial preparations, were evaluated for their capability to control the bean rust fungus Uromyces appendiculatus (Pers. ex Pers.) Unger. Different kinds of leaf disc assays were performed with conidial spore suspensions and sterile culture filtrates of the T. harzianum strains. Great differences were observed concerning the efficacy of the Trichoderma strains to reduce the number of the uredial pustules developing after rust inoculation which followed the application of the particular Trichoderma strains. Efficacy values ranged from 1 to over 50%. Increasing spore or culture filtrate concentrations of the two most effective isolates T12 and T_U led to decreases in the number of developing uredial pustules. Culture filtrate applications had a protective but no curative effect. T12 spore suspensions maintained their disease reducing activity even when autoclaved. This and some other evidence for an antibiotic interaction between T. harzianum and U. appendiculatus are discussed. Handling Editor: Reijo Karjalainen.     

Evaluation of β-1,3-glucanase and β-1,4-glucanase enzymes production in some Trichoderma species

Trichoderma species have become the important means of biological control for fungal diseases. This research was carried on to access the high β-1,3-glucanase and β-1,4-glucanase enzyme producer of Trichoderma species isolates using two different carbon sources for finding a method to obtain more concentrate culture filtrates. Therefore, 14 Trichoderma isolates belonging to species: Trichoderma ceramicum, T. virens, T. pseudokoningii, T. koningii, T. koningiosis, T. atroviridae, T. viridescens, T. asperellum, T. harzianum1, T. orientalis, T. harzianum2, T. brevicompactum, T. viride and T. spirale were cultured in Wiendling’s liquid medium plus 0.5% glycerol or 0.5% Phytophthora sojae-hyphe as the carbon source in shaking and non-shaking (stagnant) statuses. Enzyme activity rate and total protein were evaluated in raw, acetony and lyophilized concentrated culture filtrates and the specific enzyme activity of β-1,3-glucanase and β-1,4-glucanase were measured by milligramme glucose equivalent released per minute per milligramme total protein in culture filtrates. The results showed that using Phytophthora – hyphe in medium increased the enzyme activities as compared to glycerol at all Trichoderma species which suggested that these substrates can also act as inducer for synthesis of lytic enzymes, in addition the most enzymes activity was observed in the lyophilised concentrated culture filtrate. The most successful species in β-1,3-glucanase and β-1,4-glucanase enzymes activities were T. brevicompactum and T. virens and these species can be used for mass production of these enzymes which are supposed to be used in commercial formulation and also will be able to control P. sojae directly.