Biocontrol potential of Trichoderma Sp. against plant pathogens (original) (raw)
Related papers
Journal of Plant Protection and Pathology, 2014
Twenty-four fungi were isolated from five plant hosts collected from 15 governorates. The mean percentage of fungal recovery from hosts showed that Trichoderma spp. (35.98%) were the most dominant fungi. The other fungi occurred at frequencies ranged from 0.07 to 17.67%. Occurrence of Trichoderma spp. was negatively correlated with incidence of five pathogenic fungi. However, the significant correlation was observed between isolation frequency of Trichoderma spp. and isolation frequency of Fusarium spp. (r=-0.57, p= 0.03). Fifteen isolates of Trichoderma spp. were screened for their biocontrol capacity against soil-borne fungal pathogens under greenhouse conditions by using eight pathosystems. These isolates showed various levels of antagonism within each pathosystem. When the same isolates were in-vitro screened for chitinase activity, 20% of the isolates were high producers, 40% were medium producers, and 40% were low producers. Regression analysis was used to study the effect of chitinase activity (independent variable) on percentage of surviving seedlings (dependent variable) in each pathosystem. In most pathosystems, the in-vitro efficiency of Trichoderma isolates in producing chitinase was not significantly correlated with the percentage of surviving seedlings, which was used as a parameter for evaluating the antagonistic activity of Trichoderma isolates under greenhouse conditions. This finding may indicate that the in-vitro chitinase activity of Trichoderma isolates is of no practical value because it cannot be used as a criterion to predict their in-vivo performance. Grouping the isolates by cluster analysis, based on their biocontrol patterns, was not related to their chitinase activity. This result suggests that chitinase may not be involved in the biocontrol process of the tested isolates. Similarly, grouping the isolates by cluster analysis, based on their RAPD banding patterns, was not related to their chitinase activity. This result indicates that RAPD banding patterns were unable to differentiate among the isolates based on their chitinase activity.
2012
Abstrac t: Trichoderma is opportunistic, avirulent plant symbiont and pathogenic to other fungi. Chitinolytic enzyme producing Trichoderma species have long been recognized as an agent for controlling plant diseases caused by various phytopathogenic fungi. Chitin is the main structural component of fungi. Chitinase is an enzyme responsible to metabolize the chitin. Primary screening of chitinase producing fungus is essential to obtain an efficient and novel bio control agent. In this study, three Trichoderma species were isolated (Trichoderma harzianum, Trichoderma flavofuscum, Trichoderma viride ) and their macro- and microscopic observation was done. Furthermore, they were screened for its chitinase production, using Chitinase Detection Medium. The basic findings will be helpful to a mycologist for study and screening of chitinase overproducing fungi at the primary level.
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.
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.
The Journal of General and Applied Microbiology, 1997
Trichoderma harzianum is an effective biocontrol agent of several important plant pathogenic fungi. This Trichoderma species attacks other fungi by secreting lytic enzymes, including p-1,3-glucanase and chitinolytic enzymes. Superior biocontrol potential may then be found in strains having a high capacity to produce these enzymes. We have therefore evaluated the capacity of six unidentified Trichoderma spp. isolates to produce chitinolytic enzymes and a-1,3-glucanases in comparison with T. harzianum 39.1. All six isolates demonstrated substantial enzyme activity. However, while the isolates hereafter called T2, T3,, T5, and T7 produced lower amounts of enzymes, the activity of isolates T4 and T6 were 2-3 fold higher than that produced by T. harzianum 39.1. A chitinase produced by the T6 isolate was purified by a single ion-exchange chromatography step and had a molecular mass of 46 kDa. The N-terminal amino-acid sequence showed very high homology with other fungal chitinases. Its true chitinase activity was demonstrated by its action on chitin and the failure to hydrolyze laminarin and p-nitrophenyl-~i-N-acetylglucosaminide. The hydrolytic action of the purified chitinase on the cell wall of Sclerotium rolfsii was convincingly shown by electron microscopy studies. However, the purified enzyme had no effect on the cell wall of Rhizoctonia solani.
The antagonistic fungus Trichoderma harzianum is widely recognized as a potential biocontrol agent against several soil-borne plant pathogens. T. harzinum is rich source of chitinoltic enzymes. In vitro screening of 5 isolates of T. harzinum, one isolate of Chaetomium globosum and one isolate of Conetherium mentance, revealed that all of them had reduced growth area of Macrophomina phaseolina, Fusarium solaniand Rhizoctonia solani on PDA medium, significantly. The inhibition percentage ranged from 77.9 to 55.9 for M. phaseolina and 59.2 to 40.4 for R solani by T. harzinum and C. mentance, respectively. Inhibition for F. sol ani ranged from 76.5 to 55.7 by T. harzinum and C. globosum, respectively. Isozyme gel electrophoresis was used to assess chitinase activity secreted by selected isolates of T. harzinum under different pH degrees and temperatures. Obtained results indicated that activity of chitinase isozyme produced at 30 ·C was higher than 15-20 ·C for all tested isolates and activity of chitinase produced by isolates No.4 and 5 ofT. harzinum at pH (7-7.5) was higher than at pH 6, respectively.
Indian phytopathology, 2016
Trichoderma spp. are well described biocontrol fungi for its lytic activity and antagonistic properties against phytopathogens. The present studies were conducted to biochemically characterize Trichoderma spp. isolated from soils of Jammu. A total of fifty native isolates of Trichoderma spp. were screened on the basis of their antifungal activity using dual culture technique. Twenty promising isolates were evaluated for the secretion of extracellular hydrolytic enzymes viz . cellulases, chitinases and β-1, 3-glucanases. Enzyme activity detected in agar plates using their respective inducers as sole carbon sources and further tests for enzyme production in broth culture revealed that the majority of the isolates showed maximum specific enzyme activity up to 6 th day of incubation with few exceptions were FL322, OR26X and OR27 for cellulase; BR1, FL21 and CE32 for chitinase and 1CR2, AG20, FL41, FL322 and OR26X for glucanase which showed regular increasing trend up to 9 days. However,...
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.
Biocontrol Science and Technology, 2000
Biocontrol of foliar diseases is an alternative means of management of foliar pathogens. One of the most studied commercial biocontrol agents is isolate T39 of Trichoderma harzianum which can be regarded as a model to demonstrate biocontrol under commercial conditions and the mechanisms involved. This biocontrol agent (BCA) controls the foliar pathogens, Botrytis cinerea, Pseuperonospora cubensis, Sclerotinia sclerotiorum and Sphaerotheca fusca (syn. S. fuliginea) in cucumber under commercial greenhouse conditions. Control e$cacy was similar for three di!erent rates (covering a fourfold range). Involvement of locally and systemically induced resistance has been demonstrated. Cells of the BCA applied to the roots, and dead cells applied to the leaves of cucumber plants induced control of powdery mildew. The BCA suppressed enzymes of B. cinerea, such as pectinases, cutinase, glucanase and chitinase, through the action of protease secreted on plant surfaces. A combination of several modes of action is responsible for biocontrol. However, biocontrol is not achieved by means of antibiotics or by mycoparasitism, in spite of the fact that BCA has the potential to degrade cell-wall polymers, such as chitin.
Mycology, 2019
Trichoderma species were known as biological control agents against phytopathogenic fungi because they produce a variety of chitinases. Chitinases are hydrolytic enzymes that break down glycosidic bonds in chitin, a major component of the cell walls of fungi. The present study shows that extracellular chitinase activity reached a maximum value of approximately 22 U/mL after 96 h of T. asperellum PQ34 strain culture. The optimal temperature and pH of enzyme are 40°C and 7, respectively, whereas the thermal and pH stability range from 25°C to 50°C and 4 to 10, respectively. Chitinase at 60 U/mL inhibited nearly completely in vitro growth of Colletotrichum sp. (about 95%) and Sclerotium rolfsii (about 97%). In peanut plants, 20 U/mL of chitinase significantly reduced the incidence of S. rolfsii infection compared to controls. The fungal infection incidence of seeds before germination and 30 days after germination was only 2.22% and 2.38%, while the control was 13.33% and 17.95%. Besides, chitinase from T. asperellum PQ34 can also prevent anthracnose that is caused by Colletotrichum sp. on both mango and chilli fruits up to 72 h after enzyme pretreatment at 40 U/mL. In mango and chilli fruits infected with anthracnose, 40 U/mL dose of chitinase inhibited the growth of fungi after 96 h of treatment, the diameter of lesion was only 0.88 cm for mango and 1.45 cm for chilli, while the control was 1.67 cm and 2.85 cm, respectively.