Screening of native isolates of Trichoderma spp. of Jammu for their biocontrol potential through hydrolytic enzyme activities (original) (raw)
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In vitro screening for enzymatic activity of Trichoderma species for biocontrol potential
A total of seven Trichoderma species were isolated from rhizosphere soils of brinjal on potato dextrose agar medium. Based on morphological and cultural characters, the isolates were assigned to different species viz., Trichoderma viride, T. harzianum, T. virens, T. atroviride, T. koningii, T. pseudokoningii and T. reesei. Trichoderma species were screened for the production of extracellular enzymes to identify the strain with high antagonistic potential against fungal pathogens. The screening was done following plate assay method on the respective solid media. These strains were positive for cellulase, amylase, pectinase, protease and chitinase activity. The excretion of extracellular lytic enzymes reveals their usefulness in the application of Trichoderma species as biocontrol strains in agricultural soils. The use of simple solid media permits the rapid screening of large populations of fungi for the presence or absence of specific enzymes
Turkish Journal of Biology, 2003
It is well known that Trichoderma spp. can be used as a biological control agent. In this study, Trichoderma isolates were obtained from 31 different Eskisehir soil samples. The biocontrol and antifungal effects of these isolates against various plant pathogen fungi were determined. We found that all filtrates of Trichoderma harzianum T9, T10, T15 and T19 were effective against plant pathogens Fusarium culmarum, F. oxysporum, F. moniliforme, Rhizoctonia solani, Sclerotium rolfsii, Gaeumannomyces graminis var. tritici and Drechslera sorokiniana. Among these isolates, T. harzianum T19 showed a wide range of inhibitory effects on plant pathogens. F. oxysporum was found to be the most resistant to the filtrates of the strains above. All isolates showed different behaviors depending on the physiological tests carried out such as growth in the presence inhibitory substrates, pH limits of growth and hydrolysis of gelatin. T. harzianum isolates were grown on the chitin, which is the sole carbon source. The chitinase activity determined from T. harzianum T15 by SDS-PAGE was nearly 73 kDa.
Extracellular Enzyme Activity of Trichoderma Strains Isolated from Different Soil Types
2016
Enzymatic characterization of 16 Trichoderma strains, grown in potato dextrose broth was carried out semi-quantitatively by API-ZYM test. Strains that were used for test were isolated from different soil types and belonged to T. harzianum species complex, T. koningiopsis, T. atroviride, T. brevicompactum, T. gamsii, T. citrinoviride and T. longibrachiatum. The activities of acid phosphatase and naphthol-AS-BI-phosphohydrolase were high in all examined strains and N-acetyl-β-glucosaminidase activity was detected in most of them. However, activities of β-glucuronidase, α-glucosidase, β-glucosidase were negative. Among all investigated Trichoderma isolates, T.brevicompactum showed moderate αgalactosidase and β-galactosidase enzymatic activity. Obtained results are in accordance with previous results on very good antagonistic properties of examined Trichoderma strains against fungal pathogens, indicating that extracellular enzymes are important part of their antagonistic mechanism of bi...
Microorganisms
Trichoderma is the most commonly used fungal biocontrol agent throughout the world. In the present study, various Trichoderma isolates were isolated from different vegetable fields. In the isolated microflora, the colony edges varied from wavy to smooth. The mycelial forms were predominantly floccose with hyaline color and conidiophores among all the strains were highly branched. Based on morphological attributes, all the isolates were identified as Trichoderma harzianum. The molecular identification using multilocus sequencing ITS, rpb2 and tef1α, genes further confirmed the morphological identification. The average chitinase activity varied from 1.13 units/mL to 3.38 units/mL among the various isolates, which increased linearly with temperature from 15 to 30 °C. There was an amplified production in the chitinase production in the presence of Mg+ and Ca2+ and Na+ metal ions, but the presence of certain ions was found to cause the down-regulated chitinase activity, i.e., Zn2+, Hg2+,...
Determination of lytic enzyme activities of indigenous Trichoderma isolates from Pakistan
Brazilian Journal of Microbiology, 2015
This study investigated lytic enzyme activities in three indigenous Trichoderma strains namely, Trichoderma asperellum, Trichoderma harzianum and Trichoderma sp. Native Trichoderma strains and a virulent strain of Rhizoctonia solani isolated from infected bean plants were also included in the study. Enzyme activities were determined by measuring sugar reduction by dinitrosalicylic acid (DNS) method using suitable substrates. The antagonists were cultured in minimal salt medium with the following modifications: medium A (1 g of glucose), medium B (0.5 g of glucose + 0.5 g of deactivated R. solani mycelia), medium C (1.0 g of deactivated respective antagonist mycelium) and medium D (1 g of deactivated R. solani mycelia). T. asperellum showed presence of higher amounts of chitinases, b-1, 3-glucanases and xylanases in extracellular protein extracts from medium D as compared to medium A. While, the higher activities of glucosidases and endoglucanses were shown in medium D extracts by T. harzianum. b-glucosidase activities were lower compared with other enzymes; however, activities of the extracts of medium D were significantly different. T. asperellum exhibited maximum inhibition (97.7%). On the other hand, Trichoderma sp. did not show any effect on mycelia growth of R. solani on crude extract.
Indian Journal of Microbiology, 2012
Trichoderma, soil-borne filamentous fungi, are capable of parasitising several plant pathogenic fungi. Twelve isolates of Trichoderma spp. isolated from different locations of South Andaman were characterized for their cultural, morphological and antagonistic activity against soil borne and foliar borne pathogens. The sequencing of these isolates showed seven different species. The isolates revealed differential reaction patterns against the test pathogens viz., Sclerotium rolfsii, Colletotrichum gloeosporioides and C. capsici. However, the isolates, TND1, TWN1, TWC1, TGD1 and TSD1 were most effective in percentage inhibition of mycelial growth of test pathogens. Significant chitinase and b-1,3-glucanase activities of all Trichoderma isolates has been recorded in growth medium. T. viride was found with highest chitinase whereas T. harzianum was recorded with highest b-1,3glucanase activities.
Biocontrol potential of Trichoderma Sp. against plant pathogens
International Journal of Agriculture Sciences, 2009
Forty two strains of Trichoderma sp. were isolated from cultivated lands around Bangalore and analyzed for their antagonistic potential against Sclerotium rolfsii and Fusarium ciceri. The potential of biocontrol agents ultimately lies in their capacity to control pathogens in vivo. Bioefficacy studies were hence conducted using chickpea (Cicer argentums c.v. Annigeri) as an experimental plant by the roll paper towel method. Overall the isolates T40, T35, T30 and T25 showed better antagonistic potential in addition to enhancing plant growth. The production of chitinases to break down the mycelial cell walls of fungal plant pathogens has been implicated as a major cause of biocontrol activity (Inbar and Chet, 1995). In order to study the mechanism of biocontrol, ten better performing strains were plated on media, amended with colloidal chitin and Sclerotium rolfsii cell wall extract. All the isolates showed chitinolytic activity on day three as well as day five. Production of endochitinase and exochitinase were assayed in liquid media using colloidal chitin amended broth. Strains T35 and T6 displayed maximum endochitinase and exochitinase activity. Although all strains exhibited cellulase activity, the quantum of enzyme produced was higher in T35 and T6. The results also indicate a positive correlation between enzyme production and bioefficacy.
SpringerPlus, 2012
Chitin is the second most abundant polymer in nature after cellulose and plays a major role in fungal cell walls. As a producer of variety of chitinase enzymes Trichoderma has become an important means of biological control of fungal diseases. A simple and sensitive method based on the use of basal medium with colloidal chitin as sole carbon source supplemented with Bromo cresol purple (pH indicator dye) is proposed to evaluate large populations of Trichoderma for chitinase activity. The soluble substrate with pH indicator dye (Bromo cresol purple, BCP) for the assay of chitinase activity on solid media is sensitive, easy, reproducible semi-quantitative enzyme diffusion plate assay and economic option to determine chitinases. Colloidal chitin derived from Rhizoctonia cell wall and commercial chitin included as a carbon source in broth also allowed selection and comparison of chitinolytic and exochitinase activity in Trichoderma spectrophotometrically. Released N-acetyl-β-D-glucosamine (NAGA) ranged from 37.67 to 174.33 mg/ml and 37.67 to 327.67 mg/ml and p-nitrophenol (pNP) ranged from 0.17 to 35.78 X 10-3 U/ml and 0.62 to 32.6 X 10-3 U/ml) respectively with Rhizoctonia cell wall and commercial chitin derived colloidal chitin supplemented broth.
Ten species of Trichoderma were isolated from the rhizospheric soil, collected from the different locations of U.P. Both morphological and molecular characterization of the isolated species was done. All the ten isolated species were screened for chitinase enzyme production on solid agar medium using bromocresol purple for developing the clear zone around colonies, and characterized due to its antagonistic effect against mycelia growth of pathogenic fungi. The nucleotide sequences (submitted and retrieved from NCBI) of all ten Trichoderma species are analyzed through TrichOKEY 2 program for their validation post molecular identification. This has confirmed the selected sequences as specific strains of Trichoderma species.
Journal of Applied Biology & Biotechnology, 2020
In the present study, 20 fungal strains were isolated from tomato rhizosphere of Senegal. Of 20 strains, five showed the chitinolytic activity on chitin agar medium. Of the five strains, NG4 showed the maximum solubilization zone. This strain was identified by preliminary biochemical and 18S rRNA sequencing analysis. Enzyme production started after 3 days of incubation and maximum was observed after 5 days of incubation. Culture filtrate amended with 0.1% colloidal chitin was used in the production medium. The optimum conditions for maximum chitinase activity are-6 days of growth and temperature of 30°C at pH 6.0. The chitinase activity was also influenced by the addition of carbon and nitrogen sources in the production medium.