Harzianum Isolates Research Articles

Molecular characterization of plant growth-promoting Trichoderma from Saudi Arabia.

Fungi in the genus Trichoderma are widespread in the environment, mainly in soils. They are used in agriculture because of their mycoparasitic potential; Trichoderma have the ability to increase plant health and provide protection against phytopathogens, making them desirable plant symbionts. We isolated, identified, and characterized Trichoderma from different regions of Saudi Arabia and evaluated the ability of Trichoderma to promote plant growth. Morphological and molecular characterization, along with phylogenetic studies, were utilized to differentiate between Trichoderma species isolated from soil samples in the Abha and Riyadh regions, Saudi Arabia. Then, plant growth-promoting traits of the isolated Trichoderma species were assessed. Eight Trichoderma isolates were characterized via morphological and molecular analysis; six (Trichoderma koningiopsis, Trichoderma lixii, Trichoderma koningii, Trichoderma harzianum, Trichoderma brevicompactum, and Trichoderma velutinum) were from Abha and two (T. lixii and T. harzianum) were from Riyadh. The isolated Trichoderma strains belonged to three different clades (Clade 1: Harzianum, Clade 2: Brevicompactum, and Clade 3: Viride). The Trichoderma isolates varied in plant growth-promoting traits. Seeds treated with most isolates exhibited a high percentage of germination, except seeds treated with the T3-T. koningii isolate. 100% germination was reported for seeds treated with the T4-T. harzianum and T6-T. brevicompactum isolates, while seeds treated with the T1-T. koniniopsis and T5-T. lixii isolates showed 91.1% and 90.9% germination, respectively. Seeds treated with the T8-T. velutinum, T2-T. lixii, and T7-T. harzianum isolates had germination rates of 84.1%, 82.2%, and 72.7%, respectively. The Trichoderma isolate T5-T. lixii stimulated tomato plant growth the most, followed by T7-T. harzianum, T8-T. velutinum, T4-T. harzianum, T1-T. koniniopsis, T2-T. lixii, and T6-T. brevicompactum; the least effective was T3-T. koningii. A maximum fresh weight of 669.33mg was observed for the T5-T. lixii-treated plants. The Abha region had a higher diversity of Trichoderma species than the Riyadh region, and most isolated Trichoderma spp. promoted tomato growth.

The effects of EDTA and Trichoderma species on growth and Cu uptake of maize (Zea mays) plants grown in a Cu-contaminated soil.

Metal contamination in soil poses a significant environmental concern worldwide, necessitating effective remediation strategies such as phytoremediation. The present study investigated the effects of EDTA dosage (1.5 and 3mmolkg-1) and two Trichoderma species (T. harzianum and T. aureoviride) on copper (Cu) content and growth of maize plants grown in a Cu-contaminated soil, as well as Cu fractionation in the soil. In the absence of EDTA, only inoculation with T. harzianum led to a significant increase in shoot biomass. Combining fungal inoculum with EDTA only yielded a significant increase in shoot biomass when using T. aureoviride at a low EDTA rate, highlighting the interplay between fungal species and EDTA rates on plant growth. Results also indicated that EDTA application increased Cu bioavailability, enhancing Cu dissolution and root (not shoot) Cu concentrations. Conversely, inoculation with both Trichoderma species reduced Cu mobility and bioavailability in soil, thereby decreasing the shoot Cu concentrations of plants. When combined with EDTA, only application of T. harzianum resulted in an enhanced shoot Cu concentration, whereas combined application of T. aureoviride and EDTA did not make a significant change compared to the corresponding control (no fungal inoculation, no EDTA), possibly due to a lower compatibility of the T. aureoviride isolate with EDTA. Our results demonstrated that EDTA application, in both non-inoculated and inoculated treatments, increased Cu availability by facilitating its redistribution and transformation from less plant-available fractions (residual, Fe/Mn oxide-bound, and carbonate-bound) to the more readily plant-available forms (water-soluble and exchangeable fractions). In conclusion, although individual Trichoderma application proved beneficial for phytostabilization by reducing Cu content and mitigating Cu toxicity in plants, the combined application of EDTA and a compatible Trichoderma isolate (here, the T. harzianum isolate) holds promise for enhancing the phytoextraction capacity of plants. Although using maize has the advantage of being a food crop, to optimize phytoextraction, plant species with superior metal tolerance and phytoextraction capabilities should be selected, exceeding those of maize.

Discover the Most Effective Disease Management Strategies for Fusarium Dry Rot of Potato through Comprehensive Bio-assay of Three Techniques (Chemical, Plant extracts, and Bio-control)

Potato (Solanum tuberosum) is a multicultural staple food and cash crop. Unfortunately, production of potatoes is predominantly constrained by diseases including dry rots. To evaluate management of dry rots, three in vitro sub-trials were set up using the completely randomized design with each treatment replicated thrice for each trial. Firstly, synthetic fungicides were assayed against Fusarium oxysporum f.sp. tuberosi. Secondly, plant extracts were assessed against F. oxysporum. Finally, the efficacy of Trichoderma harzianum applied against F. oxysporum was evaluated. The colony radii were measured. The inhibition of F. oxysporum by Ketoconazole (at 100% concentration) was significantly (p≤0.05) highest, followed by Ketoconazole (50% concentration), Itraconazole (100% concentration), Itraconazole (50% concentration), Sulphur (100% concentration), Ridomil (100% concentration), Sulphur (50% concentration), and finally Ridomil (50% concentration). Percentage inhibition of the growth of the Fusarium species by fungicides ranged from 39.5-95.7%. Blue gum (Eucalyptus globulus) (at 100% concentration) gave the highest inhibition, followed by blue gum (50% concentration), Sweet alligator-pepper (Aframomum melegueta) at 100% concentration, locust bean (Parkia biglobosa) at 100% concentration, Sweet alligator-pepper (50% concentration), candle bush (Senna alata) (100% concentration), locust bean (50% concentration), and Senna alata (50% concentration) in descending order of percentage inhibition. Plant extracts caused a percentage inhibition of the fungus between 20.6-100% inhibition with time. Inhibition of Fusarium by T. Harzianum isolate BGMZ4 was significantly (p≤0.05) highest, followed by T. Harzianum isolate NSBM then T. Harzianum isolate BGMZ3. Control of F. Oxysporum by T. Harzianum ranged from 23.5-94.1% inhibition. All the methods evaluated successfully inhibited the pathogen compared to the control.

Characterization and evaluation of native Trichoderma harzianum P39 for biocontrol potentials against five seed-borne fungal pathogens of rice

Plant seeds can harbour pathogens that limits crop growth and productivity. This study isolated, characterised and evaluated native Trichoderma harzianum for antagonism against five (Alternaria alternata, Aspergillus oryzae, Bipolaris oryzae, Curvularia lunata and Fusarium verticillioides) fungal pathogens isolated from rice seeds. Evaluation was through simultaneous inoculation, a pathogen against the biocontrol agent, using the dual culture method in a PDA growth medium. Results confirmed the T. harzianum isolate had 98.27% pairwise identity with T. harzianum P39 (KX381171.1. accession number). The isolate showed increasing percentage inhibition, against all the pathogens, with increasing days after inoculation. The highest values ranged from 53.02%, A. oryzae to 70.06%, F. verticillioides (the least and most susceptible respectively). The overall inhibition percentages of A. alterata and B. oryzae (12th day after inoculation) were not significantly different from that of F. verticillioides. Trichoderma harzianum P39 can be formulated as biological seed dressing agent.

Internal Transcribed Spacers (ITS) Based Identification of Trichoderma Isolates and Biocontrol Activity against Fusarium oxysporum and Chitinase Activity

Twelve Trichoderma spp. isolated from different locations in Uttar Pradesh, India. Internal transcribed spacer (ITS) amplification and sequencing were used to identify isolates of Trichoderma that showed 99–100% identification with Trichoderma harzianum, Trichoderma asperellum, and Trichoderma longibrachiatum, the three species of Trichoderma. Tests were conducted in Vitro to evaluate the biocontrol potential of Trichoderma isolates against Fusarium species. After seven days of incubation, the isolate TBT6 (T. harzianum) exhibited the greatest antagonism against Fusarium oxysporum, with inhibition rates of 87.1%) by TBT7 (82.2%), and the least amount of inhibition (59.7%) by T. longibrachiatum isolate TBT10. Under field conditions, the antagonistic T. harzianum isolate TBT6 can be employed as a bio-control agent against Fusarium oxysporum. and for the development of formulations based on Trichoderma. Using the dual plate approach, twelve highly antagonistic Trichoderma isolates were selected for chitinolytic activity. Observing the breakdown of chitin substrates, Trichoderma isolates TBT6 was shown to have strong chitinolytic enzyme activity, making it a good candidate for endochitinase gene isolation. Using two particular primers, the genomic DNA of the Trichoderma isolate TBT6 was isolated and amplified.

Population dynamics of Trichoderma harzianum in bio- fortified compost against soil-borne potato diseases

Soil-borne diseases pose significant challenges to global potato cultivation, resulting in yield losses and economic implications. Utilizing biological control agents offers a sustainable and environmentally and friendly approach to manage these diseases. Before implementing the experiment in the field, a series of in-vitro tests were conducted to select a virulent isolate of the tested pathogens and an effective antagonistic isolate of Trichoderma harzianum. In the pathogenicity test, isolate RS-1 of Rhizoctonia solani and isolate SR-8 of Sclerotium rolfsii exhibited the highest virulence against two pathogens in potato variety ‘Cardinal’ in regard to seedling mortality (44.44-88.88%). During in vitro screening, T. harzianum isolate Tri 7 displayed the greatest ability to inhibit the mycelium growth of all tested pathogens. In the field trial, the highest seedling mortality (69.06%) was observed in T2 (Fresh seeds+ Soil inoculated with R. solani and S. rolfsii). However, the highest seedling mortality (86.94%) was reduced by treatment T7 (Fresh seeds+ Soil inoculated with R. solani and S. rolfsii +500g wheat grain colonized with Trichoderma fortified poultry compost). Treatment T7 also recorded the lowest incidences of stem canker (7.83%) and stem rot (8.64%), whereas the highest disease incidences occurred in the T2 treatment plot. Notably, treatment T7 gave the highest yield of 30.94 tons/ha, while the control plot T2 yielded the lowest at 12.17 tons/ha. Initially, Trichoderma population was minimal prior to the application of Trichoderma- fortified compost. However, populations gradually increased over time, peaking at 3 months across all treatments except the control, where no Trichoderma was applied. However, a decline in T. harzianum population was noted one month after potato harvesting. This approach offers a potential solution for managing potato soil-borne diseases in a sustainable and environmentally friendly manner. Ann. Bangladesh Agric. (2023) 27 (1): 81-92

Comparison of the Efficacy of Trichoderma and Bacillus Strains and Commercial Biocontrol Products against Grapevine Botryosphaeria Dieback Pathogens

Grapevine trunk diseases (GTDs) cause significant yield losses worldwide and limit the lifespan of vineyards. In the last few years, using biological control agents (BCAs) for pruning wound protection has become a promising management strategy for the control of these pathologies. This study aimed to compare the antifungal activities of a grapevine-native Trichoderma harzianum isolate and a high-potential Bacillus velezensis strain against two pathogenic Botryosphaeriaceae species in artificially inoculated, potted, grafted plants under controlled greenhouse conditions, taking three commercial biocontrol products (based on T. atroviride I-1237, T. harzianum T-22, and Bacillus subtilis BS03 strains) as a reference. To reproduce certain field conditions more realistically, inoculation of the protective agents and the pathogens was conducted simultaneously immediately after pruning instead of allowing the BCAs to colonize the wounds before pathogen inoculation. Significant differences in necrosis lengths were detected for both Neofusicoccum parvum- and Diplodia seriata-infected plants, and a remarkable protective effect of Bacillus velezensis BUZ-14 was observed in all cases. Trichoderma-based treatments showed different efficacies against the two pathogenic fungi. While the three tested BCAs resulted in significant reductions in vascular necrosis caused by N. parvum, they did not significantly reduce D. seriata infection compared to the untreated inoculated control. The B. subtilis strain was not effective. The reported results provide support for the potential Bacillus velezensis may have for pruning wound protection against Botryosphaeriaceae fungi, encouraging its evaluation under natural field conditions.

Improvement of antagonism and fungicides tolerance in Trichoderma harzianum and T.viride local isolates by Ultra-Violet irradiation

Among 22 Iraqi Trichoderma harzianum and T.viride isolates, T3,T5,D5,S1 and S6 related to T. harzianum showed a higher antagonistic activity against the plant pathogenic fungi Fusarium oxysporum and Rhizoctonia solani. These isolates were selected for improvement their biocontrol activity by usi
 ng uv-irradiation. The optimum exposure time to ultraviolet irradiation is 30 min, in which, the percentage of kill was 98-99% .After UV-irradiation treatment (Quartz lamps 30W at 240-280 nm, peak 254nm, distance from the source was 20 cm), antagonistic capability against R. solani and F. oxysporum was improved in mutants MT3,MT5,MS1 and MS6, in which antagonistic reaction score were 3.6,3.9,3.2 and 3.6 against F. oxysporum and 3.7,4,3.4 and 4 against R. solani compared to 3.2, 2.8, 2.6 and 2.8 against F. oxysporum and 2.7, 2.9,3.1 and 3 against R. solani in the wild types T3, T5, S1 and S6,respectively. The growth of T. harzianum isolates (estimated as colony diameter) was significantly increased in all T. harzianum mutants except MT3 and MD5 mutants, CMCase activity was increased from 13.2, 16.2, 10 and 15.8 U/ml / mg protein in the wild isolates T3, T5, S1 and S6 to 18.6, 20.3, 17.7 and 22.5 U/ml / mg protein in the mutants MT3, MT5, MS1 and MS6, respectively. Chitinase activity was also increased in these mutants to 88.4,132.3,86.1 and 136.7 U/ml / mg protein, compared to 82.7, 93.2, 74.5 and 103.2 U/ml / mg protein in their wild, respectively. As comparison between wild types and mutants, the maximum growth was 5.2 and 4.8 cm (as colonies diameters) by MT5 in present of 25% of the recommended field rate of Topsin and Benomyl, compared to 3.3 and 2.2 cm in the wild type T5, respectively, followed by MS6,in which, the maximum growth in this mutant was 4.8 and 4.2 cm in the same concentration of these two fungicides, compared to 3.4 and 2.5 cm in the wild type S6, respectively. According to these results, the mutants MT5 and MS6 developed from UV-irradiation treatment, showed as promising T. harzianum mutants through their antagonistic activity (at mycoparasitism level) , fast growth, higher CMCase and chitinase activity and growth in 25% of the recommended field rate of Elsa , 25 and 50% of the recommended field rate of Diathen and Mizab and all concentrations of Topsin and Benomyl with complete inhibition of pathogenic fungi F. oxysporum and R. solani.

In vitro evaluation of the antagonistic activity of native strains of Trichoderma spp. against Fusarium spp.

Five samples of agricultural soil and five samples of Aloe barbadensis (P. Mill., 1768) plants with symptoms of wilt and root necrosis were collected in five localities of the state of Tamaulipas, México. The aims of this study were the morphological identification, molecular identification and in vitro evaluation of the antagonistic activity of Trichoderma spp. on Fusarium spp. Four strains of Trichoderma asperellum, one strain of Trichoderma harzianum and five strains of Fusarium oxysporum were identified by morphological and molecular methods. The evaluation of the antagonistic activity of T. harzianum isolate (TP) showed the highest inhibition in Fusarium spp. (78.80%). The evaluation of the antagonistic activity of Trichoderma spp. extracts in Fusarium spp. did not show significant differences between treatments (P ≤ 0.05), with Trichoderma growth percentages that oscillated between 81.08 and 94.38%. The native isolate of T. harzianum (TP) showed significant competitive capability against the mycelial growth of F. oxysporum. Trichoderma species are promising agents of biological control in the central area of the State Tamaulipas, Mexico.

Genetic Diversity of Trichoderma harzianum Isolates in Sunflower Rhizosphere: The Application of the URP Molecular Marker

The genetic diversity of 77 Trichoderma harzianum isolates collected from sunflower rhizosphere soils in Urmia, Khoy, and Salmas in West Azerbaijan province, Iran, was evaluated by using the Universal Rice Primer (URP) molecular marker. The DNA band pattern of the isolates was developed using seven primers of this marker. These primers produced 186 gene loci, out of which 182 loci were polymorphic. Accordingly, the genetic diversity of the isolates was calculated, and their kinship relations were determined by cluster analysis using the NTSYS software package. URP-6R had the highest marker index among the studied primers, followed by URP-1F, URP-4R, and URP-25F, implying their higher efficiency in discriminating between the isolates. The results showed that the URP marker could discriminate between isolates using macroscopic morphological characteristics, such as color and colony type, potential of pigment production in the culture medium, and colony growth rate. Furthermore, there was no significant relationship between the geographical distribution of the isolates and the band patterns generated by the primers except for a few cases. The results generally revealed that the URP marker was an efficient tool for determining the genetic diversity of T. harzianum.

An eco-friendly approach of biocontrol of aphid (Aphis gossypii Glover) by Trichoderma harzianum.

Aphid (Aphis gossypii) is one of the important pests of papaya crop. In this work, applications of Trichoderma harzianum and Beauveria bassiana (biocontrol agents) and malathion (insecticide) were conducted in vitro and in agrifields for testing their anti-aphid efficacy and compared their efficacy. Furthermore, the enzymatic mechanism of T. harzianum with respect to biocontrolling the pest was unearthed. The LD50 dose of T. harzianum and B. bassiana was 1.2 × 105 spores mL-1 and 1.0 × 106 spores mL-1 respectively after 48h of administration. The LT50 of T. harzianum also exhibited a lower effective time (47.70h) than B. bassiana (57.53h) for the same concentration of spores applied (1 × 105 spores mL-1). The pooled data analysis of two years (2019-2020) showed that the application of T. harzianum spores in agrifields exhibited 31.75 ± 13.00a percentage of reduction of aphid population whereas malathion exhibited 23.93 ± 1.30a%, in comparison to control. The statistical analysis indicated that the application of malathion exhibited the same efficacy as T. harzianum isolate and placed in the same category. In plate detection assay, T. harzianum produced a higher hydrolytic zone for chitinase (8.0 ± 0.4cm diameter) and protease (7.0 ± 0.4cm diameter) enzymes, than B. bassiana (1.3 ± 0.2cm and 1.1 ± 0.2cm respectively). Quantitative estimation of enzymes exhibited that T. harzianum produced 299 ± 11a μg mL-1 of chitinase, 519 ± 19a μg mL-1 of protease, and 65 ± 12a μg mL-1 of PR1, and on the other hand, B. bassiana yielded 124 ± 12b, 361 ± 23b, and 29 ± 18b μg mL-1 of chitinase, protease, and PR1 respectively. It indicated that T. harzianum was superior over the B. bassiana in terms of production capacity of all three enzymes. In conclusion, all the above experimental results suggested that T. harzianum showed better aphid-killing efficacy than B. bassiana. It also suggested that T. harzianum should replace hazardous chemical pesticide (malathion) for eco-friendly biocontrol of aphids.

Trichoderma harzianum and Trichoderma asperellum are potential biocontrol agents of Meloidogyne javanica in banana cv. Grande Naine

Biological control of plant-parasitic nematodes by Trichoderma has been widely studied, especially in annual crops such as soybean and cotton, but scarcely explored in the banana crop. Phytonematodes often attack banana plantations, and the species of Meloidogyne typically are the most frequent. Depending on the nematode population, they lead to yield losses or even plant death. Despite several Trichoderma commercial products registered in Brazil as biofungicides or bionematicides, there is a single one recommended to manage Meloidogyne incognita, with no approvals for M. javanica. The objective of this study was to evaluate two Trichoderma harzianum isolates (ALL42 and IBLF006) and the T. asperellum T00 strain as antagonists of M. javanica and as inducers of systemic resistance on bananas. Greenhouse experiments were conducted by treating seedlings of the Grande Naine susceptible cultivar with conidia suspension of the isolates. The enzymatic activity of CHId and GLUeon banana leaves was evaluated at 7, 14, and 21 days after inoculation (DAI). Plant growth and nematode population were evaluated at 60 DAI. T. harzianum ALL42 and T. harzianum IBFL006 reduced the M. javanica population on banana roots by up to 55.2 % and 67.9 %, respectively, in contrast to T. asperellum T00 that was inefficient. Enzymatic activity of CHI in plants non-inoculated with the nematode was higher at 14 DAI and decreased afterward. CHI and GLU activity were higher at 21 DAI in plants treated with isolate IBFL006 and grown in infested soil. The treatments did not promote plant growth. The effect of T. harzianum isolates was tested “in vitro” as filtrate or conidia suspension on mortality of J2 individuals. ALL42 and IFBL006 non-autoclaved filtrates promoted the highest M. javanica mortality rates of 59.6 %, and 68.8 % respectively.

Antagonism Of Trichoderma Species Against Major Soil Borne Plant Pathogens

In the current study, ten isolates of Trichoderma harzianum and T. hamatum collected from different agro climatic zones of Maharashtra were tested for antagonism against important soil borne phytopathogenic fungi (Fusarium ciceri, Rhizoctonia bataticola and Sclerotium rolfsii) using dual culture assay. In comparison to the controls, all T. harzianum isolates had a significant antagonistic effect on pathogen mycelial growth in dual cultures. T. harzianum (AkTr2) inhibited radial mycelial growth by 77.78%, 78.52% and 75.93% in Fusarium ciceri, Rhizoctonia bataticola and Sclerotium rolfsii respectively. Whereas T. hamatum (AkTm1) inhibited 75.93%, 75.56% and 73.70% growth of Fusarium ciceri, Rhizoctonia bataticola and Sclerotium rolfsii respectively. The isolate AkTr2 was the most promising and resulted in the greatest growth inhibition in R. bataticola, while AkTm1 resulted in the least growth inhibition in Sclerotium rolfsii (73.70 %).

Potency of two Trichoderma harzianum isolates in liquid and solid organic formula for controlling bacterial wilt on tomato in the field

This research aimed to determine the potency of two Trichoderma harzianum isolates in solid and liquid organic formulas to control bacterial wilt and on growth and yield of tomato in the field. This research was carried out at the Laboratory of Plant Protection and the tomato field at Banteran Village, Sumbang Sub-District, Banyumas Regency at altitude of 600 m above sea level for four months. A randomized block design was used with five replicates. The treatments were control, T. harzianum T10, T. harzianum T215, combination of T. harzianum T10 + T. harzianum T215, and bactericide (a.i. 20% streptomycin sulfate). Variables observed were pathosystem components (incubation period, infection rate, disease intensity, and late populations of the antagonists), growth components (plant height, plant fresh and dry weight, and root fresh and dry weight), yield components (number of fruits, fruit weight), and phenolic compounds analysis qualitatively. The results showed that T. harzianum T10 + T. harzianum T215 was effective to suppress the disease as 58.61%. The treatment of T. harzianum T10 + T. harzianum T215 was effective to increase crop height, fresh weight of plants, dry weight of plants, fresh weight of roots, dry weight of roots, number of fruits and fruit weight as 38.86, 35.37, 51.67, 24.78, 37.41, 40.61, and 53.22%, respectively. All treatments could increase phenolic compound content qualitatively.

Efficacy of T harzianum isolates in plant growth promotion and BLB management in rice

Rice crop is highly vulnerable at all stages of growth to different pathogens that affect the quality and quantity of its yield. Among the different diseases, Bacterial blight of rice (Xanthomonas oryzae pv. oryzae), a deadly bacterial disease is among the most destructive affliction of cultivated rice (Oryza sativa and O. glaberrima). In severe epidemics, crop loss may be as high as 75 percent, and millions of hectares of rice are infected annually. Biological control based on antagonism is a potential, non-chemical and eco-friendly approach for managing plant diseases. Biocontrol agents like Trichoderma spp. are acclaimed as effective, eco-friendly and cheap, nullifying the ill effects of chemicals. The present study involved five different isolates of Trichoderma harzianum viz. IRRI-2, IRRI-3, IRRI-4, IRRI-5, IRRI-6 obtained from International Rice Research Institute. Variations were observed while comparing the efficacy of different Trichoderma harzianum isolates, IRRI-5 and IRRI-2 isolates exhibited superior anti-bacterial activities in vitro. Rice crop was raised from Trichoderma treated seeds and further challenge inoculates with Xoo to induce disease in plants. All the T. harzianum treated plants had lower incidence of diseases and higher yield than the untreated plant. Yield attributing characters like plant height, days of active tillering, panicle initiation and maturity, total number of grains per panicle, number of filled grains per panicle was positively influenced by Trichoderma harzianum application. However, there were variations among the treatment, isolate IRRI-5 was found most effective followed by IRRI-2, IRRI-4, IRRI-3 and IRRI-6 respectively.

Efficacy of T harzianum isolates in plant growth promotion and BLB management in rice

Efficacy of T harzianum isolates in plant growth promotion and BLB management in rice

BIODEGRADATION OF SOME ENVIRONMENTAL POLLUTANTS BY LACCASE PRODUCED FROM TRICHODERMA HARZIANUM USING SOLID STATE FERMENTATION

Trichoderma harzianum produced 5.383 U/mg of laccase in solid state fermentation (SSF) using 10gm of wheat bran as substrate with moisture content 1:0.7 w/v, using 4 plugs×5mm as inoculums size, for 7 days at 28C°. Laccase was partially purified with 7.260 fold and yield 84.01% by ion exchange chromatography DEAE-cellulose. Partially purified laccase had an optimum pH of 4 and was stable in pH range from 3.5 to 5.5. The optimum temperature for laccase activity was 35C° and stability was range from 15 to 35C° with 1h of incubation. The ability of T. harzianum isolate to decolorize textile dyes on solid media appears completely decolorization of Blue dye with concentrations 50,100 and partially decolorized with concentration 150,200 and 250 ppm, while the Yellow dye and Red dye were completely decolorized at 50 ppm concentration. The ability of partial purified laccase to degradation of phenol was completely occurs in concentration 5, 10 but at 20, 50 and 100 ppm about 90.94%, 93.93%and 36.78% respectively, while furfural degradation at 5 and 10 ppm was about 86.84% and 68.66% respectively which detected using HPLC technique.

Efficiency and delivery methods of Trichoderma harzianum on biological control against southern blight in sweet pepper

Soilborne pathogens are difficult to control with limited options, and it is important to seek effective alternatives for management. The objective of this study was to evaluate the effect of Trichoderma harzianum on the biological control of southern blight. The commercial product Trichodermil, containing the antagonist, was used for in vitro antagonism evaluation, followed by in vivo assays, with different forms of biocontrol application in Capsicum annuum seedlings inoculated with Sclerotium rolfsii. The biocontrol conditions used in the tests were: 1) without inoculation of the pathogen; 2) furrow spraying; 3) foliar spraying; 4) immersion of roots in spore suspension; 5) without biocontrol. The T. harzianum isolate tested produces antifungal metabolites that reduce mycelial growth and germination of the pathogen. In the in vivo tests, an effect of the application in the sowing furrow on the root mass of the plants was observed. However, none of the treatments prevented plant mortality. The biocontrol agent T. harzianum does not work as a stand-alone strategy for management of southern blight, but has potential for use in integrated management programs.

Molecular Characterization of Sclerotinia sclerotiorum Sacc. Initiating White Mold Disease in French Bean (Phaseolus vulgaris L.) and its Biological Management

Background: White mold disease caused by S. sclerotiorum is a serious peril to the cultivation of french bean in India. The disease primarily spreads by spores and normally in forms of sclerotia, which can remain viable in soil for several years and under appropriate environmental conditions, germinate to form mycelium, leading to infectious hyphae or producing apothecia. Methods: In the present study, antagonistic activity of locally isolated bio-inoculants including four fungi and three bacteria were evaluated against white mold disease of french bean. In vitro efficacy of bio-inoculants was tested by dual culture method against S. sclerotiorum. Result: The molecular characterization of isolated pathogen was performed using ITS sequencing. The sequence length of the pathogen was 516 bp and approximately identical to publicly available S. sclerotiorum sequences on NCBI data base. In vitro study showed that, P. fluorescens isolate Pf008 was best causing 95.55 per cent mycelium growth reduction. In field experiment, the bio-inoculants were tested by various inoculation methods. Sclerotinia sclerotiorum infested soil treated with bio-inoculants as seed treatment and soil application. Results revealed that, seed treatment with formulation of T. harzianum isolate TS004 was best and enhance the growth promotion and increase the grain yield i.e. 13.93 q/ha and 12.10 q/ha during the year 2018-19 and 2019-20 respectively. Soil application with formulation of T. viride isolate TS006 was the utmost effective in reducing disease incidence by 83.91% during the year 2018-19 and seed treatment with formulation of T. viride isolate TS006 reducing disease incidence by 74.83% in the year 2019-20.

ISOLATION AND MOLECULAR DIAGNOSIS OF TRICHODERMA SPP. AND EVALUATION OF ITS EFFECTIVENESS AGAINST DERMATOPHYTES

Dermatophyte infection of the human is difficult to eradicate with drug treatment. An alternative approach to treat dermatophytes might be the application of biological control agents against fungal diseases. Trichoderma spp, were isolated from the soil in Adana province of Turkey. 4 species were identified based on DNA-ITS and ITS4 sequence. T. viride, T. virens, T. harzianum and T. lixii. We tested Trichoderma species against Trichophyton tonsurans and Microsporum canis. All isolates of Trichoderma showed promising results in reducing the growth of pathogens under in vitro conditions, with different concentrations and dual culture assay. However, antagonistic assessment of isolates of Trichoderma against pathogens T.tonsurans and M.canis by concentrations assay (5,10 and 15 ml/L) showed variation in inhibition of pathogens. The colony diameter growth values ranging in all concentrations and isolates from 0.46 to 5.40 cm, The best antifungal concentration was (15 ml/L) with T. harzianum isolate in inhibition for T. tonsurans and M. canis, which reached 0.50 and 0.46 cm respectively. For dual culture assay showed that all isolates of Trichoderma reduced growth T.tonsurans and M.canis. Moreover, the highest inhibition with T. harzianum isolate Which colony diameter reached 1.34 and 1.50 cm, respectively.