Trichoderma Asperellum Research Articles

Characterization and evaluation of bioformulation from antagonistic and flower inducing Trichoderma asperellum isolate UCRD5

Trichoderma species due to their fungal plant pathogen suppression and ecofriendly nature are Trichoderma species due to their fungal plant pathogen suppression and ecofriendly nature are deployed in agriculture as biocontrol agents for the management of plant diseases in agricultural crops since a long-time. The potential biocontrol species/strains of Trichoderma from native geographic locations are often used for the effective management of various abiotic and biotic stresses in plants. Furthermore, bioformulation of biocontrol strains are often prepared using different carriers and evaluated for their effectiveness. Therefore, the isolates of Trichoderma were evaluated against plant fungal pathogens such as Fusarium oxysporum, Sclerotinia sclerotiorum, Alternaria solani and Phytophthora sp. suppression. The pot experiments carried in tomato plants inoculated with a combination of pathogens and one of the most effective Trichoderma asperellum isolate UCRD5 revealed that beside disease suppression, the biocontrol strain led to the significantly early induction of flowering in plants, compared to control. Further, characterization of talc powdered and calcium alginate based bioformulation of Trichoderma asperellum isolate revealed better shelf-life for calcium alginate based bead bioformulation. Keeping in view the difference in the biocontrol potential of Trichoderma isolates from different geographic locations, the present study explores the native isolates of Trichoderma from the agricultural fields of Punjab region, for the effective management of various abiotic and biotic stresses in agricultural crops. Further, efforts were made to enhance the shelf-life and biocontrol efficacies using sodium alginate based beads. The ability of the indigenous Trichoderma isolated to suppress plant fungal pathogens and induce flowering in tomato, coupled to encapsulated formulations with better shelf-life indicates its potential in enhancing the agricultural productivity.

Structural Elucidation and Total Synthesis of Trichodermotin A, A Natural α‐Glucosidase Inhibitor from Trichoderma asperellum

Comprehensive SummaryA pair of alkaloid enantiomers possessing a novel 1‐oxaspiro[4.4]non‐3‐ene‐2,7‐dione skeleton, trichodermotin A (1), was obtained from the fungus Trichoderma asperellum. Spectroscopic data, X‐ray diffraction, and ECD calculations were used to establish its structure and absolute configuration. (−)‐1 showed significant α‐glucosidase inhibitory activity (IC50 = 10.1 μmol/L vs. 60.1 μmol/L of positive control). A plausible biosynthetic pathway originating from L‐β‐phenylalanine was proposed, and a facile total synthesis was further accomplished. The key reaction of our synthetic strategy was a domino aza‐Michael/lactonization in one pot, leading to the pivotal 4‐amino‐oxaspiro[4.4]octane scaffold.

Efficacy of native Trichoderma asperellum in managing Alternaria solani causing early blight of Solanum lycopersicum Mill

The biocontrol efficacy of Trichoderma asperellum strain M23 (bioagent) was tested against early blight pathogen (Alternaria solani strain NO4) of tomato. These fungi were co-inoculated on tomato plants (variety UC82B and Ibadan local) at different spore concentrations, viz., 1.0 × 105, 1.0 × 107 and 1.0 × 109 while untreated plant served as control. The effect of these treatments was studied based on growth parameters, biomass and symptoms observed on disease incidence scale of 1–7. The pathogen exerted varying effects on the tomato plants as Ibadan local was more susceptible compared to UC82B. The bioagent M23 exhibited significant growth stimulatory effect (p < 0.05) on the two varieties of tomato. The antagonistic effect of M23 against NO4 was confirmed on the growth, biomass accumulation (phytomass) and fruit weight of tomato plants co-inoculated with the pathogen and the antagonist. This study demonstrated the potentials of Trichoderma asperellum not only as biocontrol agent against early blight of tomatoes but also as growth stimulatory agent for the crop.

Production of pectinases towards the extraction of natural pectin from orange peels using fungal sources

Pectin is a polysaccharide, which is present in middle lamella of cell wall of higher plants. Almost all fruits have a part of pectin in their cell walls. Pectinases are used in the degradation of the plant material and promptly extract juices from different fruits. For this purpose, identified fungi were screened qualitatively and quantitatively for the production of pectinase at 30 ºC for 92 hours of incubation time. In liquid state fermentation, identified strains of Trichoderma asperellum, Aspergillus niger and Thermomyces were treated in which Trichoderma asperellum produced maximum pectinase activities (9.2 U/ml) after 24 hours of incubation by using orange peels as a sole carbon source. Furthermore, pectinases produced from fungal strains were used to produce natural pectin from fruit waste like orange peels. During fermentation process, pectinase produced from fungal strains were inoculated to dried orange peels for 24 hours of incubation time at 30 ºC. The filtered extract was treated with 3 volumes of 80% ethanol for washing to extract pectin. Trichoderma asperellum gave maximum pectin yield [(11.7%)], Aspergillus niger and Thermomyces gave minimum pectin yield [(9.7%, 7.5%)] from orange peels respectively and the amount of pectin yield extracted from orange peels control was [(3.5%)]. Pectinases and pectin has found huge industrial applications in soft drinks, dairy products, pharmaceuticals and food industries, therefore, the present work has focused on the cost effective production of pectinase enzyme and extraction of natural pectin by using potential indigenous fungal strains.

Morphological characterization of Trichoderma spp. isolated from the oil palm rhizosphere in peat soils and its potential as a biological control for Ganoderma boninense in vitro

Trichoderma sp. is a saprophytic fungus found in various environments, one of which is in the rhizosphere of oil palm plants which can be used to control Ganoderma and increase the resistance of oil palm plants from stem rot disease. This study aimed to characterize the morphology of Trichoderma spp. origin of peat land in oil palm plantations in Kampar Regency and screening the potential in controlling Ganoderma sp. Trichoderma spp. from oil palm rhizosphere was collected from the smallholder oil palm plantations in Deli Makmur Village, Kampar, Indonesia. This research was conducted by several observations, such as the hypovirulence test; identification of the morphology of Trichoderma spp. fungus; growth and diameter test of Trichoderma spp. fungus; test of the inhibitory ability of Trichoderma spp. fungus against Ganoderma sp. LPTUNRI-Gan002 isolate; test for hyperparasitism of the fungus Trichoderma spp., which has high antagonistic power against Ganoderma sp. isolate. Six Trichoderma spp. isolates had morphological characteristics similar to two species, i.e., Trichoderma harzianum (LPTUNRI-Trc001, Trc004, Trc005, and Trc006 isolates) and Trichoderma asperellum (LPTUNRI-Trc002 and Trc003). LPTUNRI-Trc003 had the highest diameter (90 mm), growth rate (32.66 mm/day), and the highest ability to suppress Ganoderma sp. LPTUNRI-Gan002 (91.03%) compared to the other five isolates.

Management of Tomato Damping-off Disease in the Nursery Using of Trichoderma asperellum

The study was conducted during 2018−19 and 2019−20 to evaluate effectiveness of the Trichoderma asperellum liquid formulation for the management of tomato damping-off in the nursery. The experiment was conducted for two consecutive seasons in a randomized block design with seven treatments and three replications. T. asperellum formulation improved seed germination and controlled the damping-off diseases in tomatoes when compared with control. All the treatments performed better over control, in the first season, the antagonist’s application showed 75.75% seed germination; however, it was 60.13% in control. There was 10.93 to 20.38% seedling mortality due to disease which was comparatively lower than the control (26.98%). A similar trend of seed germination and disease incidence was observed in the second season. In addition to managing the disease, the antagonist certainly promoted vegetative growth which was reflected as increased shoot and root length in comparison to control during both seasons. During the first season, shoot length ranged 10.90–12.85 cm as compared to the control (8.72 cm) and root length ranged from 3.21–3.65 cm which was greater than the control. Almost a similar trend in the vegetative growth parameters of seedlings was observed during the second season. The present investigation showed that the tested antagonist’s formulation could efficiently manage the tomato damping-off as well as encouraged the vegetative growth of seedlings which ultimately ensured better and healthy seedling. This formulation can successfully be used through different methods to take care of tomato damping off.

Phytophthora cinnamomi causing root rot on Rhododendron lapponicum and control it using potential biocontrol agents.

Rhododendron lapponicum (R. lapponicum) is a dwarf Rhododendron species, which is severely infected with root rot and wilt in Yunnan province, China. However, the causal agent causing these symptoms was unknown. An isolate, Pci-1 was identified as Phytophthora cinnamomi, based on its morphology and the sequences of β-tubulin, internal transcribed spacer, and Ypt1 genes and verified according to the Koch's postulate. We found that this pathogen could infect 14 species of plants, including Althaea rosea, Viburnum cylindricum, and Brassica napus. Strain Pci-1 could cause R. lapponicum to wither and die; and it grows best in an oat medium with pH 7.0 - 8.0 and an optimum temperature of 27°C. We suggest that the rhizosphere of R. lapponicum treated with biocontrol strains Paenibacillus polymyxoides P2-5 and Trichoderma asperellum Tv-1 showed a significant inhibitory effect on pathogen Pci-1. The inhibitory effect of 70% dimethomorph + cymoxanil was significantly higher with EC50 and EC90 values of 0.1894 and 0.3618 a.i. µg/ml, respectively. Greenhouse experiments revealed that the pathogen load is decreased in the presence of potential antagonists. This study provides fundamentals on risk assessment and theoretical support for the management of P. cinnamomi pathogen and contributes significantly to the planting of forest and horticultural crops in a disease-free environment.

Microbial production of multienzyme preparation from mosambi peel using Trichoderma asperellum.

Fruit and vegetable wastes create unhygienic conditions and pose a environmental pollution. The utilization of such wastes as carbon sources for production of enzyme with microbial intervention could be an ecofriendly and profitable approach, apart from diminishing the waste load. The present investigation focused on the feasibility of using mosambi (Citrus limetta) peel as substrate for multienzyme production (pectinase, cellulase and amylase) through microbial intervention. Fifteen fungi were isolated from organic waste and screened in vitro their potential of biodegradation of mosambi peel through enzymes production. The best performing isolate was selected and identified as Trichoderma asperellum NG-125 (accession number-MW287256). Conditions viz. temperature, pH, incubation time and nutrient addition were optimized for efficient enzymes production. The maximum enzyme activity (U ml-1min-1) of pectinase (595.7 ± 2.47), cellulase (497.3 ± 2.06) and amylase (440.9 ± 1.44) were observed at pH 5.5, incubation temperature of 30°C after 10days of fermentation. Moreover, macro-nutrients such as ammonium sulfate (0.1%) and potassium-di-hydrogen-ortho-phosphate (0.01%) further also enhanced the production of enzymes. The SDS-PAGE analysis of purified pectinase, cellulase and amylase using showed molecular mass of 43, 66 and 33kDa, respectively. The enzyme retention activity (ERA) of aforesaid enzymes was also tested with four different natural fiber matrices viz., bagasse, rice husk, paddy straw and wheat straw. Among these, the maximum ERA was observed on bagasse matrix (pectinase-56.35%, cellulose-77.68% and amylase 59.54%). Enzymatic juice clarification yield obtained with test enzyme was 75.8%, as compared to 80.5% of commercial enzyme. The result indicates that T. asperellum may be exploited as multifaceted biocatalysis.

Efficiency of Trichoderma asperellum as a promoter of vegetable growth and soybean productivity

Aiming to achieve greater economic returns by increasing the biomass and productivity of strategic crops, such as soybeans, this article aimed to evaluate the efficiency of TrichoPlus (Trichoderma asperellum), as a promoter of plant growth in soybeans. Four independent experiments were carried out in the municipalities of Porto Nacional and Gurupi, Tocantins, Brazil, in the 2017/2018 and 2018/2019 harvests. Four experiments were conducted, each with four treatments with different doses of TrichoPlus (2, 3, 4 and 5 g kg-1 per seeds), plus two control treatments, one positive control with commercial product based on Trichoderma asperellum and one absolute control (without inoculation). For the treatment with the TrichoPlus product, the powder formulation was used, with active ingredient based on Trichoderma asperellum 201, formulated with a minimum concentration of 2 x 108 CFU g-1. The positive results for the biomass characteristics, stand maintenance and productivity were evidenced in the different doses of TrichoPlus, with emphasis on doses close to 5 g kg-1 of seeds, with gains in productivity above 23% for the 2017/2018 harvest and above 9% for the 2018/2019 harvest in Gurupi. In Porto Nacional the productivity gain for the 2017/2018 harvest was over 21% and for the 2018/2019 harvest it was over 27% in relation to the absolute control. Considering the different doses of TrichoPlus used in the experiments, there were differences between the doses with the best results for treatments with doses of 4 and 5 g kg-1 of seeds.

Phenethoxy Derivatives with Anti-inflammatory Activities from the Betelnut Endophytic Trichoderma asperellum G10.

Eight new phenethoxy derivatives, trichoasperellins A-H (1-8), were isolated from the endophytic fungus Trichoderma asperellum G10 isolated from the medicinal plant Areca catechu L. The structures of these compounds were elucidated from spectroscopic data, J-based configurational analysis, and Mosher's methods. Compounds 1-4 and 6-8 bear one or two multioxidized C7 moieties with the same carbon skeleton. The carbon skeletons of compounds 6-8 are new, all containing three moieties connected via two acetal carbons similar to those of disaccharide glycosides. Compound 4 inhibited nitric oxide production with an IC50 value of 48.3 μM, comparable to that of the positive control indomethacin (IC50, 42.3 μM).

Effect of water content on conidia of Trichoderma spp., indole acetic acid content, electrical conductivity, and pH

Abstract. Purwanto B, Sumadi, Nuraini A, Setiawati MR. 2022. Effect of water content on conidia of Trichoderma spp., indole acetic acid content, electrical conductivity, and pH. Biodiversitas 23: 2553-2560. Trichoderma sp. is a soil-borne saprophytic fungus that can increase plant resistance to combat drought stress. However, some species are unable to survive in a low water environment. Therefore, this research aimed to determine the effect of water content on different species of Trichoderma with respect to total conidial growth, IAA content, electrical conductivity (EC), and the media’s pH. A factorial Completely Randomized Design (CRD) with 2 factors, namely the water content of the media consisting of 3 levels (5%, 25%, and 50%) and the inoculation of Trichoderma spp. which includes Trichoderma harzianum, Trichoderma asperellum, and Trichoderma viride. Furthermore, an experimental method was adopted by analyzing the total conidial growth, indole acetic acid content (IAA), electrical conductivity (EC), and acidity (pH) of the media. Incubation was carried out for 14 days, data were analyzed using one way ANOVA, and Duncan's Multiple Distance Test was applied to determine the parameters that have a significant effect. The results showed that the total conidia of T. harzianum at the lowest water content (5% of the dry weight of the media) showed an increase from 7th to 14th days after inoculation (DAI), the highest was 23.6%, followed by T. asperellum (12.6%) and T. viride (10.7%). Similarly, the total conidia of Trichoderma spp. positively correlated with the levels of IAA, EC, and pH of the media. This indicates that an increase in total conidia is followed by an increase in the IAA content, EC, and pH. The highest total of T. harzianum conidial growth at the lowest water content indicated that it had better resistance to drought stress than T. asperellum and T. viride.

Supplementation of Manure Compost with Trichoderma asperellum Improves the Nutrient Uptake and Yield of Edible Amaranth under Field Conditions

Manure composts can improve soil health and crop production, but their application with Trichoderma species has not been well evaluated in amaranth cultivation. This study aimed to determine the effects of manure compost (MC) and MC supplemented with Trichoderma asperellum CHF 78 (MC+CHF 78) on the yield and nutrient uptake of amaranth, as well as on soil properties, under field conditions. Four fertilization treatments, including a control without fertilization, chemical fertilization (CF), MC, and MC+CHF 78, were arranged in a randomized complete block design with six replications in the experimental field. MC and MC+CHF 78 significantly increased the yield of amaranth by 96.2–102% in comparison with CF. In addition, MC and MC+CHF 78 significantly increased the soil pH, soil organic matter, soil available P and exchangeable K, and soil microbial activity compared with those in the control and CF treatments. However, only amaranth plants applied with MC+CHF 78 showed a significantly greater P uptake than those with the control and CF treatments, which may be attributed to the phosphate-solubilizing ability of T. asperellum CHF 78. In conclusion, manure compost fortified with T. asperellum CHF 78 can be used as an alternative to chemical fertilizers for amaranth cultivation.

The Endophyte Trichoderma asperellum M2RT4 Induces the Systemic Release of Methyl Salicylate and (Z)-jasmone in Tomato Plant Affecting Host Location and Herbivory of Tuta absoluta.

The use of endophytic fungi has dramatically increased plant performance through the enhancement of plant protection against abiotic and biotic stressors. We previously demonstrated that the endophytic fungus Trichoderma asperellum M2RT4 improves tomato defenses against the tomato leafminer Tuta absoluta through the reduction of oviposition, leafmining, pupation, and adult emergence. However, the underlying mechanism by which the presence of this endophytic fungus within tomato host plant affects T. absoluta host selection and life-history traits is unknown. We tested the behavioral responses of T. absoluta in Y-tube olfactometer bioassays and found that females preferred non-inoculated tomato plants against those inoculated by endophytes. Additionally, T. absoluta females were not attracted to non-inoculated infested nor to inoculated-infested tomato plants. Chemical analysis revealed the emission of methyl salicylate in inoculated tomato plant and an increase in the amounts of monoterpenes emitted from non-inoculated infested plants. Additionally, we found that upon herbivory, T. asperellum M2RT4 modulates tomato plant chemistry through the production of (Z)-jasmone thus activating both salicylic and jasmonic acid defense pathways. Further, T. absoluta females were attracted to monoterpernes including α-pinene, 2-carene, and β-phellandrene but repelled by methyl salicylate. Methyl salicylate could therefore be considered as a good semiochemical-based candidate for sustainable T. absoluta management using a “push-pull” approach. However, in dose-response bioassays, females of T. absoluta did not show any preference to the four component-blend (α-pinene, 2-carene, β-phellandrene, and methyl salicylate). (Z)-jasmone-treated tomato leaflets significantly reduced the leafmining activity of the pest at the concentration of 10 ng/μL and causing the highest larval mortality rate (83%) with the shortest LT50 (1.73 days) 7 days post-treatment. T. asperellum M2RT4 effect on herbivore performance was then (Z)-jasmone-mediated. These findings expand our understanding of how the endophytic fungus T. asperellum M2RT4 could mediate chemical interactions between T. absoluta and its host plant which are potentially important for development of environmentally friendly T. absoluta management programs.

Trichoderma asperellum (NST-009): A potential native antagonistic fungus to control Cercospora leaf spot and promote the growth of 'Green Oak' lettuce (Lactuca sativa L.) cultivated in the commercial NFT hydroponic system

Leaf spot caused by Cercospora lactucae-sativae is one of the most damaging diseases of ‘Green Oak’ lettuce in Thailand. This study was conducted to estimate the effectiveness of Trichoderma asperellum NST-009, a native strain in Thailand, to manage the leaf spot disease and enhance the growth of ‘Green Oak’ lettuce in a nutrient film technique (NFT) hydroponic system. In vitro tests showed that T. asperellum NST-009 significantly inhibited the mycelial growth of C. lactucae-sativae by 72.50%, and its antifungal metabolite from the culture filtrate of T. asperellum NST-009 inhibited the mycelial growth of C. lactucae-sativae by 93.26%. In the hydroponics experiment, T. asperellum NST-009 reduced the disease severity index by 67.51% compared to the inoculated control and significantly stimulated the growth of the ‘Green Oak’ lettuce in terms of the plant height (8.62%), canopy width (16.67%), leaf number (18.39%), shoot fresh weight (25.71%), root fresh weight (39.26%), and total P in the leaves (31.45%) compared to the control. In addition, T. asperellum NST-009 was found to survive in both the lettuce leaves and roots at 100.00%.

In silico and biochemical analysis on a newly isolated Trichoderma asperellum l-asparaginase

Microbial l-asparaginase enzyme has been considered as a good source of potential anticancer drugs. The enzyme purified from different microbes has been shown different biochemical and kinetics properties. Thus, our study aims to investigate l-asparaginase from Trichoderma asperellum (MN960163), including in silico characterization of the l-asparaginase encoding genes as well as the biochemical characters of the purified enzyme. In silico, analysis of the T. asp genome database revealed the presence of six protein encoding genes with N-terminal asparaginase domain that has asparaginase production potential as indicated from their physico-chemical properties, verification of three of them was confirmed. T. asperellum l- asparaginase with a specific activity of 200 U/mg and 61.7 fold purification was achieved by ammonium sulphate precipitation (60%) followed by DEAE-sepharose ion exchange and Sephacryl S-200 gel filtration chromatography. The purified enzyme has a molecular mass of 65 kDa and exhibited its maximum activity at pH 8 and 50 °C. The purified enzyme showed high thermal stability up to 50 °C and a high affinity to l- asparagine with a Km of 0.35 mM. The activity was significantly enhanced by Cu, K and Ca ions while Fe and EDTA was completely inhibited l-asparginase activity. In conclusion, the current data highlight new possible genes that could be employed as a promising source in asparaginase production for medical purposes. Additionally, the feature of the purified asparaginase enzyme could help to elucidate the unique properties of T. asp asparaginase.

Effective Biocontrol of Rice Blast through Dipping Transplants and Foliar Applications

Rice (Oryza sativa) is an increasingly popular food in Africa. As much as 30% of yields are lost due to blast disease caused by Magnaporthe oryzae. Several commercial biopesticides of Bacillus subtilis, Trichoderma asperellum, and Serratia sp. strains were evaluated under field conditions for their effects against rice blast and yield at one site in Kenya and three sites in Tanzania in 2020 and 2021. Each biopesticide was applied as a dipping treatment at transplanting, post-transplanting foliar spraying, or both. Using biopesticides not only achieved blast control but also increased grain yield, particularly in low-production regions in Tanzania, with a yield increase of &gt;100%. For higher-production sites with low disease pressure, the yield increase through biopesticides over the untreated control was limited, although significant disease suppression was achieved. Dipping alone was sufficient to suppress disease and improve yield unless disease pressure was high. The differences among the three biopesticides varied with site/year but generally were small. Improved yield using biopesticides is unlikely to result solely from reduced blast development, but also from improved plant development. The present study suggests that these commercial biopesticides should be applied in rice production, particularly in subsistence farming.

Trichoderma Asperellum strains as potential biological control agents against Fusarium verticillioides and Ustilago maydis in maize

ABSTRACT Globally, corn is the most economically important crop, surpassing crops such as wheat, rice and barley. However, the presence of pathogenic fungi associated with corn, have favoured the appearance of diseases that cause economic loss. Therefore, the aim of the present study is to assess the efficacy of treatments in vitro and in vivo with Trichoderma asperellum in controlling the disease severity and the yield reduction in corn plants caused by Fusarium verticillioides and Ustilago maydis. In vitro confrontation experiments demonstrated the high antagonistic capacity of the T. asperellum strains, which is able to reduce the radial growth of the pathogen’s colonies from 88.71% up to 100%. In the field experiments treatments 6 and 7, where T. asperellum was confronted with F. verticillioides and U. maydis, showed a significant reduction in the average damage of the disease by 8.3 ± 6.7 and 9.5 ± 3.0, and an increase in their grain yield by 4.43 ± 0.33 and 4.11 ± 0.15 t/ha, respectively. Similarly, the percentage of good ears of 66.75 ± 5.4 and 70.37 ± 5.4, obtained in treatments 6 and 7, was higher than those values obtained in treatments 2 and 3 without Trichoderma confrontation. These results indicate that the selected Trichoderma strains isolated from Zea mays could effectively control these phytopathogenic fungi in field.

Effects of Marine Antagonistic Fungi against Plant Pathogens and Rice Growth Promotion Activity

Ten marine-derived fungi crude extracts, namely Emericella stellatus KUFA0208, Eupenicillium parvum KUFA0237, Neosartorya siamensis KUFA0514, N. spinosa KUFA 0528, Talaromyces flavus KUFA 0119, T. macrosporus KUFA 0135, T. trachyspermus KUFA0304, Trichoderma asperellum KUFA 0559, T. asperellum KUFA 0559 and T. harzianum KUFA 0631 were determined for their fungicidal activity against five rice pathogens in vitro. The results showed that the extracts of E. stellatus KUFA0208 and N. siamensis KUFA0514 exhibited the best antifungal activity, causing complete cessation of the mycelial growth of Alternaria padwickii, Bipalaris oryzae, Fusarium semitectum, Pyricularia oryzae and Rhizoctonia solani at 10 g/L. The N. siamensis KUFA0514 extract was fractioned and antifungal compounds were found in the fractions derived from petroleum-ether and chloroform (7: 3) evidenced by inhibition zones against the mycelial growth of A. padwickii around the disc containing each fraction. Moreover, in rice growth promotion tests, diluted cultural broth of T. asperellum KUFA 0559 and T. harzianum KUFA 0631 were found to strongly promote rice shoot and root elongation; however, higher concentrations of all marine fungal broths resulted in significantly reduced rice seedling growth rather than promotion. Meanwhile, Trichoderma showed great indole-3-acetic acid (IAA) production leading to the optimum IAA values of 45.38 and 52.30 µg/ml at 11 and 13 days after inoculation, respectively. The results of this study indicated that marine fungi are promising agents having antagonistic mechanisms involving antibiosis production and plant growth promotion and may be developed as novel biocontrol agents for rice disease management.

Myco-Synergism Boosts Herbivory-Induced Maize Defense by Triggering Antioxidants and Phytohormone Signaling.

BackgroundBiocontrol strategies are the best possible and eco-friendly solution to develop resistance against O furnacalis and improve the maize yield. However, the knowledge about underlying molecular mechanisms, metabolic shifts, and hormonal signaling is limited.MethodsHere, we used an axenic and a consortium of entomopathogenic Beauveria bassiana OFDH1-5 and a pathogen-antagonistic Trichoderma asperellum GDFS1009 in maize and observed that consortium applications resulted in higher chlorophyll contents and antioxidants activities [superoxide dismutase (SOD), peroxidase (POD), proline, protease, and polyphenol oxidase (PPO)] with a decrease in O. furnacalis survival. We performed a comprehensive transcriptome and an untargeted metabolome profiling for the first time at a vegetative stage in fungal inoculated maize leaves at 0-, 12-, 24-, 48-, and 72-h post insect infestation.ResultsThe consortium of B. bassiana and T. asperellum leads to 80–95% of O. furnacalis mortality. A total of 13,156 differentially expressed genes were used for weighted gene coexpression network analysis. We identified the six significant modules containing thirteen candidate genes [protein kinase (GRMZM2G025459), acyl-CoA dehydrogenase (GRMZM5G864319), thioredoxin gene (GRMZM2G091481), glutathione S-transferase (GRMZM2G116273), patatin-like phospholipase gene (GRMZM2G154523), cytochrome P450 (GRMZM2G139874), protease inhibitor (GRMZM2G004466), (AC233926.1_FG002), chitinase (GRMZM2G453805), defensin (GRMZM2G392863), peroxidase (GRMZM2G144153), GDSL- like lipase (AC212068.4_FG005), and Beta-glucosidase (GRMZM2G031660)], which are not previously reported that are highly correlated with Jasmonic acid - Ethylene (JA-ET) signaling pathway and antioxidants. We detected a total of 130 negative and 491 positive metabolomic features using a ultrahigh-performance liquid chromatography ion trap time-of-flight mass spectrometry (UHPLC-QTOF-MS). Intramodular significance and real time-quantitative polymerase chain reaction (RT-qPCR) expressions showed that these genes are the true candidate genes. Consortium treated maize had higher jasmonic acid (JA), salicylic acid (SA), and ethylene (ET) levels.ConclusionOur results provide insights into the genetics, biochemicals, and metabolic diversity and are useful for future biocontrol strategies against ACB attacks.

The effects of soil solarization and application of a Trichoderma biocontrol agent on soil fungal and prokaryotic communities

AbstractSoil solarization and biological control are two management strategies that have been used globally to manage soil‐borne plant pathogens. However, the broader effects of these strategies on soil microbial communities have not been well described. Soil prokaryotic and fungal communities were investigated by environmental DNA amplicon sequencing as part of field trials conducted in San Rafael, CA, and in Corvallis, OR. We examined microbial community changes following soil solarization, amendment with the biocontrol agent Trichoderma asperellum (TA), or solarization followed by application of the biocontrol agent. Soil solarization caused significant changes to prokaryotic and fungal communities by reducing species richness and diversity. Soil water potential was determined to be a significant factor affecting the prokaryotic community. Application of TA to solarized or nonsolarized soil did not significantly alter the microbial communities. However, solarization resulted in diminished microbial densities that appeared to enhance subsequent establishment of the biocontrol agent. This study revealed how specific environmental variables of heat intensity and soil moisture contribute to changes in the abundance of individual taxa and taxonomic groups.