Trichoderma Asperellum Research Articles

Impact of Trichoderma asperellum on Chilling and Drought Stress in Tomato (Solanum lycopersicum)

The acceleration of climate change is necessitating the adoption of shifts in farming practices and technology to ensure the sustainability of agricultural production and food security. Because abiotic stresses such as drought and chilling represent major constraints on agricultural productivity worldwide, in this study, the mitigation of such stresses by the fungus Trichoderma asperellum HK703 was evaluated. The fungus was grown on whole grain oats, kaolin and vermiculite for 5 days and then the formulation was mixed with the potting soil to colonize the roots of the plants. The effect of the bioinoculant on tomato under drought or chilling was analyzed in tomato (Solanum lycopersicum) plants. Leaf, stem and root succulence, electrolyte leakage, the relative growth rate of plant height, stem thickness and leaf area, as well new leaf emergence and chlorophyll content were determined. The results showed that drought or chilling increased electrolyte leakage and reduced plant growth and development traits and chlorophyll (a,b) content. However, inoculation with T. asperellum eliminated or reduced most of the negative impacts of drought compared to the non-stressed plants, with the exception of chlorophyll b content. Furthermore, inoculation with T. asperellum improved some of the evaluated features in chilling stressed plants but had no effect on plant height or chlorophyll (a,b) content. The results of this study indicate that T. asperellum was more effective in alleviating drought than chilling stress in tomato plants.

Induced reprogramming of oxidative stress responses in cucumber by Trichoderma asperellum (Iran 3062C) enhances defense against cucumber mosaic virus

Cucumber mosaic virus (CMV), with the widest host range among viruses, causes drastic yield losses in hosts. Due to the lack of appropriate and efficient control methods, development of new strategies to control CMV are necessary. The study of the host-pathogen-antagonist interaction from a biochemical and molecular perspective is of crucial importance for understanding the dynamics of infectious processes. Herein, we demonstrate the activity of the fungus Trichoderma asperellum (Iran 3062C) against CMV in cucumber plants. T. asperellum had the ability to control CMV infection in cucumber by inhibiting the virus, as assessed by the absence of the CMV amplification using Q-PCR. Molecular mechanisms underlying mediated resistance induced by T. asperellum were investigated by Q-PCR and the results confirmed that transcription levels of resistance-related genes (pr1, pal1, etr1, sod, rip and lox1), increased effectively in the presence of T. asperellum against CMV. Evaluation of reactive oxygen species (ROS) and ROS scavenging enzymes (SOD, LOX1, POX, CAT) level showed significantly different increase in the hydrogen peroxide (H2O2) content in plants infected by CMV alone or in the presence of T. asperellum, confirming the involvement of ROS in plant defense responses. In conclusion, the Q-PCR and enzymatic assay results illustrated a significant increase in the JA/ET/SA related genes and enzymes, which suggested that T. asperellum (Iran 3062C) was able to induce systemic resistance against CMV, involving JA/ET/ SA signaling pathway.

Isolation and Selection of some Antagonizing Fungal Strains of Trichoderma And Chaetonium that can Inhibit the Growth of Pathogenic Fungi on Orange Trees

Decline disease has been discovered for a long time but infection is more extensively increasing. It is difficult to detect because the disease is originated from roots. Among the causes, soil fungi have been widely determined. Using fungicides is not an effective way to control the disease. In this case, biocontrol with suitable microbial strains is a potential approach. This study aims to investigate in vitro the possibility of using Trichoderma and Chaetonium to control the causing fungi. Two Chaetonium strains and 1 Trichoderma asperellum strain were isolated from diseased-root samples. Six strains of Trichoderma (isolated strains T1, T2, T3, T4, T5, T6) and three strains of Chaetonium (isolated strains C1, C2, C3) showed a reasonably antagonistic ability to Phytophthora, Fusarium, Rhizoctonia. Base on the PCR identification method, 6 strains of Trichoderma was isolated belonging to Trichoderma asperellum species, and 3 strains of Chaetonium belonging to 2 species Chaetomium globosum and Chaetomium cichlids.

Diversity analysis of antagonistic microbes against bacterial leaf and fungal sheath blight diseases of rice

BackgroundBiocontrol is an effective strategy in the integrated management of plant diseases, now more as a necessity than choice, in the present era of environmental and health awareness. Microbial diversity is a wonder by nature that inspires to explore and accordingly, the diversity analysis of the isolated microbes revealed their morphological and molecular differences. The DNA provides a common platform to store the microbial information in the form of databases in public domain that can be used by anyone from anywhere.ResultsExploration for native microbes in the present study resulted in isolation of different isolates of Trichoderma and Bacillus. The microbes were identified using morphological traits and molecular markers and the key conserved 18S and 16S gene sequences submitted with the appropriate repositories. Nucleotide analysis indicated a close phylogenetic relationship between BIK 2 and BIK 3 (Bacillus isolates) and within all the 5 Trichoderma isolates. The percent disease reduction of Rhizoctonia solani and Xanthomonas oryzae pv. oryzae (Xoo) was more in plants treated with consortia of the Trichoderma (61.13%) and Bacillus (53.59%) isolates, respectively. Screening of plant growth promotion activities, percentage increase in root (41.00%) and shoot length (44.77%) were found to be maximum in Trichoderma consortia treated plants.ConclusionsThree Bacillus and one Trichoderma strains, viz., B. velezensis, B. subtilis and B. paralicheniformis and Trichoderma asperellum, were identified and found to be effective against R. solani and Xoo pathogens of rice. In vitro and in vivo studies indicated that TAIK1 and BIK3 were found to be the most potential isolates among others isolated. Ability to improve plant growth was more pronounced by consortia of microbes.

Decolourization of malachite green dye by endolichenic fungi from the lichen Usnea sp.: A novel study on their dye removal potential

ObjectiveThis novel study explored the potential of two endolichenic fungi, Pseudopestalotiopsis theae (PT, accession number MG881833) and Astrocystis bambusae (AB, accession number MH370741) in decolorizing Malachite Green (MG). MethodsTheir efficacy in dye decolorization was compared to non-endolichenic fungus Trichoderma asperellum (TA, accession number KP792512). Decolorization test was performed using MG (100 ppm) for 14 days (absorbance at 617 nm) to determine decolorization efficiency (DE, %). The pellet was collected for FTIR analysis (4000 to 700 cm−1, 50-scan speed) while the supernatant was analysed with UV-spectral analysis (300–800 nm) to detect for biodegradation. ResultsP. theae demonstrated the highest decolorization efficiency (DE%) at 89.22%, followed by T. asperellum (76.19%) and A. bambusae (67.69%). Common functional groups (i.e., OH, COOH, NH, CH, CO, CH) were detected in all isolates and their roles in biosorption were evident by the shifts in peaks and peak intensity. Biodegradation of MG was concluded based on UV-spectra peaks at 617 nm, which were significantly reduced (or absent). ConclusionThis study is the first to reveal that endolichenic fungi P. theae and A. bambusae are capable of decolorizing the toxic dye malachite green.

Introduction of Trichoderma spp. biocontrol strains against Sclerotinia sclerotiorum (Lib.) de Bary change soil microbial community composition in common bean (Phaseolus vulgaris L.) cultivation

Biological control represents a promising alternative to maintain the viability and productivity of different agricultural crops. In this work, dry bean (Phaseolus vulgaris L.) was grown in a field contaminated with Sclerotinia sclerotiorum (Lib.) de Bary, the causal agent of white mold disease. We analyzed the impact of the application of antagonistic strains of Trichoderma harzianum ESALQ-1306 and Trichoderma asperellum BRM-29104 on the edaphic native microbiota and endophytic fungal community. The structure of the fungal and bacterial communities was evaluated by next generation sequencing of the 28S and 16S rRNA genes, respectively. The results showed that the introduction of the strains changed the composition of the community without significantly affecting the parameters of abundance and alpha diversity (Anova P > 0.05). Ascomycota (54.8%) and Actinobacteria (37.2%) were predominant in the analyzed communities. Hill's diversity profiles of the treatments were similar in terms of diversity and dominance, being higher in a 90-day period and in the control treatment. NMDS and UPGMA analysis show that treatments of different lengths have low similarity in their composition, however, treatments where Trichoderma spp. were inoculated were relatively similar to the control. T. harzianum ESALQ-1306 promoted a greater quantity of indicator OTUs, 17 in total. T. harzianum ESALQ-1306 and T. asperellum BRM-29104 alter the size (1140 and 449 nodes respectively), connectivity parameters such as average degree (79.28 and 22.29 links respectively) and predominant topological roles in co-occurrence networks, but they do not alter the richness or abundance of orthologous genes. Cultivation time and plant organs were the factors that most influenced the structure of the microbial community. Trichoderma harzianum ESALQ-1306 and T. asperellum BRM-29104 promote the biological control of white mold without deleterious effects on the edaphic and endophytic bean communities.

Bioformulation development via valorizing silica-rich spent mushroom substrate with Trichoderma asperellum for plant nutrient and disease management

The present investigation was performed to valorize paddy straw (PS) based silica (Si) rich Spent Mushroom Substrate (SMS) of Pleurotus ostreatus for Plant Nutrient and Disease Management in wilt (caused by F. oxysporum f. sp. lycopersici) susceptible tomato plant F1 Hybrid King 180. Raw PS and SMS generated by P. ostreatus cultivated on PS only, and PS amended with 5% soybean cake (SC) were bio-fortified with Trichoderma asperellum (TA). SMS (PS+ 5% SC) was found supporting the growth of T. asperellum to an extent of 12.37 × 1013 conidia/g substrate. GC-MS analysis of SMS detected several bioactive metabolites like Palmitic acid, Oleic acid, Methyl linoleate, Stigmasterol, etc., known for plant health management. Bioformulations were developed employing Press Mud (PM) and Talcum Powder (TP) as carrier materials. Among the different bioformulations tested in pots study; SMS (PS+ 5% SC) SiTAPM, collectively named as TF-I, provided improved levels of morpho-biochemical and nutritional parameters, i.e., Plant Biomass (2.27 folds), Root Volume (1.75 folds), Chlorophyll (2.66 folds), Carotenoids (2.42 folds), Number of Fruits (1.76 folds), Fruit Biomass (2.02 folds), Total Soluble Sugars (2.32 folds), Total Soluble Proteins (1.70 folds), and nutraceutical parameters as Lycopene (1.42 folds), β-carotene (2.65 folds) and Ascorbic Acid (1.54 folds), along with significant (p < 0.05) reduction in the Disease Severity Index (84.34%–21.23%), over the pathogen affected plant taken as control. The fruits and leaves garnered under TF-I displayed Total Polyphenol Content (TPC) of 74.5 and 126.9 mg g−1 gallic acid, respectively, with 83.73% DPPH and 72.25% FRAP activity, indicating the elicitation of antioxidant properties in tomato fruits. EDS analyses showed 21.53% Si in SMS, and plant mapping investigation indicated a substantial accumulation of Si, which is well conceded to promote growth, disease resistance, and antioxidant parameters. The study also endorsed the use of PM over TP, as TF-I recorded an acceptable conidial count (2.22 × 108 cfu/g) towards the end of six months storage period over other bioformulations. Overall, the study envisages the development and application of innovative methodology (TF-I), offering an eco-friendly alternative for producing quality crops and a sustainable solution to waste management, thus delivering a holistic contribution towards the circular economy.

A novel Trichoderma asperellum isolate promoting the growth, detoxification, and antifungal abilities of Arabidopsis thaliana seedlings under Fusarium oxysporum toxin stress

A novel Trichoderma asperellum isolate promoting the growth, detoxification, and antifungal abilities of Arabidopsis thaliana seedlings under Fusarium oxysporum toxin stress

Interactive effect of biocontrol agents in the management of Fusarium rot in cardamom and its impact on plant defense mechanism

Cardamom plantations are subjected to constant threat due to the Fusarium rot disease caused by Fusarium oxysporum Schlecht which is pronounced during summer months. The current study deals with the identification of an effective and ecofriendly management practice for the disease through the use of biocontrol agents. Survey conducted between February and May 2019 revealed maximum disease severity and incidence in Pampadumpara panchayat of Nedumkandam block (84.40% and 100%) and minimum in Erattaar panchayat of Kattappanablock (50.40% and 60.00%). A pot culture experiment was conducted to study the effect of three bioagents (Glomus fasciculatum, Trichoderma asperellum and Pseudomonas fluorescens) individually as well as in combinations. Root inoculation of G. fasciculatum with basal application and spray with P. fluorescens as well as root inoculation of G. fasciculatum along with basal application of T. asperellum and P. fluorescens spray were identifiedto be effective against the disease. Disease suppression by the above bioagents was facilitated by reduced pathogen antagonist ratio in the soil, high level of mycorrhizal colonization in the roots and enhanced biochemical activity of defense enzymes like peroxidase, poly phenol oxidase and phenylalanine ammonia lyase in the plants.

The Potential of Endophytic Fungi in Promoting Rice Plant Growth and Suppressing Blast Disease

Endophytic fungi are fungi that inhabit the internal tissues of plant and belong to a group of microorganisms reported to have beneficial effects on plants. In this study, three endophytic fungi isolated from rice plant tissue were identified as Trichoderma asperellum, Curvularia chiangmaiensis, dan Fusarium solani. These three fungi have the ability to produce IAA between 3.03 to 6.00 µg/mL. For phosphate solubility assay, all endophytic fungi showed a clear zone around the colonies in Pikovskaya medium and could dissolve phosphate in the range of 2.74 to 17.61 µg/mL. In addition, in vivo observations of the inoculation endophytic fungi can reduce the intensity of blast disease in rice plant. So that, it can be seen that the three fungal isolates can become plant growth promoting fungi and can also used as bicontrol agents for blast disease in rice plant.

The bud rot pathogens infecting cannabis (Cannabis sativa L., marijuana) inflorescences: symptomology, species identification, pathogenicity and biological control

Bud rot pathogens cause diseases on Cannabis sativa L. (cannabis, hemp) worldwide through pre- and post-harvest infections of the inflorescence. Seven indoor or outdoor cannabis production sites and three hemp fields were sampled for bud rot and stem canker presence during 2019–2020. Among 178 isolates recovered from diseased tissues, sequences of the ITS1-5.8S-ITS2 region of rDNA, the glyceraldehyde-3-phosphate dehydrogenase (G3PDH) gene and the heat shock 60 (HSP) gene identified the following: Botrytis cinerea (162 isolates), B. pseudocinerea (2), B. porri (1), Sclerotinia sclerotiorum (5), Diaporthe eres (3) and Fusarium graminearum (5). Pathogenicity studies conducted on fresh detached cannabis buds inoculated with spore suspensions or mycelial plugs showed that B. cinerea, S. sclerotiorum and F. graminearum were the most virulent, while B. pseudocinerea, B. porri and D. eres caused significantly less bud rot. Optimal growth of Botrytis species occurred at 15–25°C. In vitro antagonism tests showed that Bacillus spp., Trichoderma asperellum and Gliocladium catenulatum inhibited B. cinerea and S. sclerotiorum colony growth. When applied as a spray 48 h prior to B. cinerea inoculation, all biocontrol agents significantly (P < 0.01) reduced disease development on detached inflorescences. Prolific growth and sporulation of T. asperellum and G. catenulatum were observed on bud tissues. The pathogens B. porri, S. sclerotiorum, D. eres and F. graminearum are described for the first time as cannabis bud rot pathogens. Inoculum from neighbouring fields of diseased garlic, cabbage, blueberry and hay pasture, respectively, likely initiated infection of inflorescences. Several biological control agents show potential for disease reduction through competitive exclusion.

Larvicidal potential of cell wall degrading enzymes from Trichoderma asperellum against Aedes aegypti (Diptera: Culicidae).

Aedes aegypti is a mosquito vector of arboviruses such as dengue, chikungunya, zika and yellow fever that cause important public health diseases. The incidence and gravity of these diseases justifies the search for effective measures to reduce the presence of this vector in the environment. Bioinsecticides are an effective alternative method for insect control, with added ecological benefits such as biodegradability. The current study demonstrates that a chitinolytic enzyme complex produced by the fungus Trichoderma asperellum can disrupt cuticle formation in the L3 larvae phase of A. aegypti, suggesting such biolarvicidal action could be used for mosquito control. T. asperellum was exposed to chitin from different sources. This induction of cell wall degrading enzymes, including chitinase, N-acetylglucosaminidase and β-1,3-glucanase. Groups of 20 L3 larvae of A. aegypti were exposed to varying concentrations of chitinolytic enzymes induced with commercial chitin (CWDE) and larvae cell wall degrading enzymes (L-CWDE). After 72 h of exposure to the CWDE, 100% of larvae were killed. The same percent mortality was observed after 48 h of exposure to L-CWDE at half the CWDE enzyme mixture concentration. Exoskeleton deterioration was further observed by scanning and electron microscopy. Our findings indicate that L-CWDE produced by T. asperellum reflect chitinolytic enzymes with greater specificity for L3 larval biomolecules. This specificity is characterized by the high percentage of mortality compared with CWDE treatments and also by abrupt changes in patterns of the cellular structures visualized by scanning and transmission electron microscopy. These mixtures of chitinolytic enzymes could be candidates, as adjuvant or synergistic molecules, to replace conventional chemical insecticides currently in use.

Trichoderma asperellum alters fungal community composition in saline–alkaline soil maize rhizospheres

AbstractThe Songnen Plain is an important agricultural region in China with an abundance of saline–alkaline soil that significantly restricts maize growth. Trichoderma spp., free‐living fungi, are commonly used biofertilizers. The effects of Trichoderma asperellum on the fungal community in saline–alkaline soils remain unclear; hence, in this study, three T. asperellum conidium suspension concentrations were used: 0 g (control), 0.7 g (low dose), and 1.4 g (high dose) over three consecutive years, following which high‐throughput sequencing was conducted to analyze the effect of T. asperellum on fungal diversity in the rhizosphere soil. Changes in crop yield, soil salt ion content, and pH were also monitored. T. asperellum treatment effectively regulated the soil salt ion balance, lowered the pH, and improved the crop yield by 4.88–20.26%. Additionally, the T. asperellum treatment significantly increased the relative abundance of T. asperellum and Ceratobasidium sp and inhibited that of the pathogenic fungi Neonectria and Fusarium. Changes in the soil fungal community composition were closely associated with soil properties and yield. Our findings suggest that long‐term T. asperellum exposure can alleviate saline–alkaline stress for maize growth by decreasing soil pH and salt ion content and regulating the fungal microbial community, thereby increasing crop yield.

Transformation of calcite (CaCO3) into earlandite [Ca3(C6H5O7)2·4H2O] by the fungus Trichoderma asperellum BDH65

Biotransformation of amorphous calcium carbonate into calcite and other inorganic calcium minerals is a worldwide phenomenon in the bacterial kingdom. In this study, it showed that calcite (CaCO3) could be transformed into an organic mineral earlandite [Ca3(C6H5O7)2·4H2O], through the dissolution of calcite and subsequent crystallization by the fungus Trichoderma asperellum BDH65. Observations by light microscopy showed that the fungal induced crystal particles were deposited as irregularly granular accumulations of micro globular particles. Scanning and transmission electron microscopy revealed that each micro globular particle consists of numerous needle-like crystals with domed end assembling radially with their ends pointing outside from its centers. This is clearly different from the shapes of microsheets formed by the chemical method. The mineral phase of the fungal catalyzed crystals is identified as earlandite, which is chemically identical to calcium citrate tetrahydrate. Structure and properties of the fungal formed crystals are further characterized by Fourier transform infrared spectroscopy and thermogravimetry, showing a similar pattern with those observed for chemically synthesized calcium citrate tetrahydrate. The current result may useful for understanding bioweathering of minerals and rocks, and insight into the calcium cycling driven by fungi.

In Vitro Antagonistic Study of Maize Root Colonizing Fungal Isolates Against Fusarium moniliforme Causing Ear Rot Disease of Maize

In the present study, different root colonizing fungal isolates were isolated from the rhizospheric soil of maize growing areas of Uttar Dinajpur, West Bengal. All the isolates including test pathogen were identified from Indian Type Culture Collection, New Delhi. Plant growth promoting maize root colonizing fungal isolates- Penicillium pinophilum (ITC NO. 11,201.19), Trichoderma harzianum (ITC NO.11,203.19), Trichoderma asperellum (ITC NO. 11,209.19), Aspergillus niger (ITC NO. 11,204.19) and Penicillum purpurogenum (ITC NO. 11,207.19) exhibited antagonistic activities against F. moniliforme (ITC NO. 11,208.19) in vitro. Two antagonistic isolates of T. harzianum and eleven strains of T. asperellum showed antibiosis mechanism for antagonism against F. moniliforme with the range of Percent Inhibition of Radial Growth from 62.41% to 88.57%. Competitive mode of antagonism against test pathogen by the isolates of P. pinophilum, P. purpurogenum and six isolates of A. niger were found. Percent of inhibition of radial growth ranged from 57.14% to 91.42%. In our finding, antagonistic isolates especially Trichoderma harzianum (ITC NO. 11,203.19), Trichoderma asperellum (ITC NO. 11,209.19) strains either single or in combination with rest maize root colonizing strains could be used as potent growth promoters as well as biocontrol (BCA) agents.

Screening of ligninolytic fungi for bioremediation of dyes

Water pollution is a growing concern worldwide. One of the main causes of water pollution includes the textile industry which produces a large amount of wastewater every day. This wastewater is known to contain dyes that are recalcitrant and hard to treat. In order to solve this problem, bioremediation using ligninolytic fungi is commonly used for the ligninolytic enzymes which are able to break down the dyes. In this study, samples were collected from decaying woods and soils in the vicinity of UiTM Puncak Alam forests. A total of 20 fungal isolates were tested for ligninolytic enzyme production. Out of the 20 isolates, 13 were found to produce lignin peroxidase and manganese peroxidase, but only one produced laccase. The isolate that produced all three enzymes was used for DNA isolation and identified using amplification of the ITS region by PCR. The isolate was identified as Trichoderma asperellum, a soft rot fungal species which is renowned for its role in bioremediation as a biosorbent.

Saline\u2013alkaline stress in growing maize seedlings is alleviated by Trichoderma asperellum through regulation of the soil environment

A significant proportion of the land area of Heilongjiang Province, China, is composed of saline–alkaline soil, which severely inhibits maize growth. Although Trichoderma treatment is widely regarded as a promising strategy for improving the soil environment and promoting plant growth, the mechanism through which Trichoderma asperellum enhances maize resistance to saline–alkaline stress is not clear. In this study, we explored the effect of T. asperellum application at different concentrations to soil saline–alkaline environment on the seedlings of two maize cultivars, assessing the biochemical parameters related to oxidation resistance. Increasing spore densities of T. asperellum suspension effectively regulated the soil ion balance in the rhizosphere of maize seedlings, reduced the soil pH by 2.15–5.76% and sodium adsorption ratios by 22.70–54.13%, increased soil nutrient content and enzyme activity, and improved the soil environment for seedling growth. Additionally, T. asperellum treatment increased the maize seedling content of osmo-regulating substances and rate of glutathione:oxidised glutathione (43.86–88.25%) and ascorbate:oxidised ascorbate (25.26–222.32%) by affecting the antioxidant enzyme activity in the roots, increasing reactive oxygen species scavenging, and maintaining the osmotic balance and metabolic homeostasis under saline–alkaline stress. T. asperellum also improved the saline–alkaline tolerance of maize seedlings by improving the root growth characteristics. Moreover, results showed that Trichoderma applied at high concentration had the greatest effect. In conclusion, improvement in the saline–alkaline tolerance of maize seedlings by T. asperellum under saline–alkaline soil conditions may be achieved through diverse effects that vary among maize cultivars.

The Microflora of Maize Grains as a Biological Barrier against the Late Wilt Causal Agent, Magnaporthiopsis maydis

The maize pathogen Magnaporthiopsis maydis causes severe damage to commercial fields in the late growth stages. This late wilt disease has spread since its discovery (the 1980s) and is now common in most corn-growing areas in Israel. In some fields and sensitive plant species, the disease can affect 100% of the plants. The M. maydis pathogen has a hidden endophytic lifecycle (developed inside the plants with no visible symptoms) in resistant corn plants and secondary hosts, such as green foxtail and cotton. As such, it may also be opportunist and attack the host in exceptional cases when conditions encourage it. This work aims to study the pathogen’s interactions with maize endophytes (which may play a part in the plant’s resistance factors). For this purpose, 11 fungal and bacterial endophytes were isolated from six sweet and fodder corn cultivars with varying susceptibility to late wilt disease. Of these, five endophytes (four species of fungi and one species of bacteria) were selected based on their ability to repress the pathogen in a plate confrontation test. The selected isolates were applied in seed inoculation and tested in pots in a growth room with the Prelude maize cultivar (a late wilt-sensitive maize hybrid) infected with the M. maydis pathogen. This assay was accompanied by real-time qPCR that enables tracking the pathogen DNA inside the host roots. After 42 days, two of the endophytes, the Trichoderma asperellum, and Chaetomium subaffine fungi, significantly (p &lt; 0.05) improved the infected plants’ growth indices. The fungal species T. asperellum, Chaetomium cochliodes, Penicillium citrinum, and the bacteria Bacillus subtilis treatments were able to reduce the M. maydis DNA in the host plant’s roots. Studying the maize endophytes’ role in restricting the invasion and devastating impact of M. maydis is an essential initial step towards developing new measures to control the disease. Such an environmentally friendly control interface will be based on strengthening the plants’ microbiome.

Isolation and Identification of Trichoderma asperellum, the Novel Causal Agent of Green Mold Disease in Sweetpotato.

Postharvest disease is an important limiting factor for sweetpotato production. Recently, a new green mold disease was found in sweetpotato storage roots. To investigate the mechanism underlying the pathogenesis of the disease, the pathogen was isolated and identified based on morphological and molecular features, and its characteristics were further analyzed by pathogenic and antagonistic evaluations. The results showed that the isolated pathogen (CRI-Ta1) was identified as Trichoderma asperellum based on the similar growth and morphological features with Trichoderma spp., 99% homology of internal transcribed spacer (ITS) sequence, and membership to the same phylogenetic group with the model strain of T. asperellum (CBS 433.97). The pathogenic analysis revealed that CRI-Ta1 could cause green mold disease through wound infection on the storage roots and the strains reisolated from infected storage roots could cause disease in different sweetpotato varieties, which was fulfilled in Koch's postulate. Moreover, CRI-Ta1 could also infect other common crop species, including chestnut, carrot, apple, pear, and others. It indicated that CRI-Ta1 was the pathogen to the storage roots of sweetpotato and had a wide host range. Additionally, in vitro antagonistic evaluation showed that CRI-Ta1 effectively inhibited the growth of common sweetpotato pathogens, including Fusarium solani and Rhizopus nigricans. However, further research is needed on the potential of CRI-Ta1 to control sweetpotato diseases in vivo. Collectively, our findings provided valuable insights into the characteristics of the T. asperellum CRI-Ta1 in sweetpotato and would be helpful to the prevention and control of sweetpotato green mold disease.

Metarhizium robertsii in combination with Trichoderma asperellum reduce the malathion doses used to control ambrosia beetles: the case of Xyleborus affinis

ABSTRACT Invasive ambrosia beetles and their symbiotic fungi are responsible for destructive diseases like Laurel Wilt and Fusarium Dieback. Some biological treatments and chemical pesticides (e.g. malathion) have been proposed as alternatives to control these pests, however, to date there are no effective treatments. Here we evaluated the susceptibility of the ambrosia beetle Xyleborus affinis Eichhoff to the entomopathogenic fungus Metarhizium robertsii strain Xoch 8.1, and the efficacy of the mycopathogenic fungus Trichoderma asperellum strain Th-T4 (3) to inhibit the growth of the pathogenic ambrosia fungus Fusarium euwallaceae strain 744. Also, we compared the efficacy of a combination of M. robertsii Xoch 8.1 and T. asperellum Th-T4 (3) against X. affinis, and examined the feasibility of using this combination as an alternative to reduce the malathion doses that have been proposed to control ambrosia beetles. The treatment of X. affinis with M. robertsii (1 × 107 con/mL) alone or in combination with T. asperellum (1 × 106 con/mL) resulted in an average mortality of 76% (±7.5), which was statistically similar to that obtained with malathion at 600 ppm (96% ± 4.0). The combination of a lower concentration of malathion (60 ppm or 200 ppm) and both fungi was as efficient as malathion at 600 ppm. Mortality in negative controls (without fungal conidia or malathion) resulted in an average of 16% (±7.5). The proposed combined treatment reduces by up to one order of magnitude the required amount of malathion, and thus represents a potential alternative to control ambrosia beetle pests.