scholarly journals Influence of chitinase production on the antagonistic activity of Trichoderma against plant-pathogenic fungi

2020 ◽  
Vol 41 (6) ◽  
pp. 1501-1510
Author(s):  
Y.S. Mazrou ◽  
◽  
A.H. Makhlouf ◽  
M.M. Hassan ◽  
A. Baazeem ◽  
...  

Aim: The present study aimed to investigate the antagonistic activity of Trichoderma strains with high chitinase production against some plant pathogenic fungi. Methodology: A total of twenty-four Trichoderma isolates were extracted from soil samples collected at different geographical locations in Egypt and Saudi Arabia. These isolates were screened for their chitinase production ability using colloidal chitin media. Six isolates with high chitinase ability were identified as T. harzianum by internal transcribed spacer (ITS) region sequencing. These strains were tested for their ability to degrade chitin into N-acetyl-β-D-glucosaminidase. Finally, the biocontrol activities of these Trichoderma strains against pathogenic fungi were tested by dual culture technique. Results: The maximum activity among the chitinolytic enzymes was 0.051 units ml-1 in Trichoderma strain ABSA19, which showed an activity comparable to the control: pure enzyme, (0.047 units ml-1). The lowest activity (0.014 units ml-1) was found in Trichoderma strain MEG2. In dual culture, Trichoderma strain ABSA19 exerted the highest antagonistic activity in addition to hyphal intertwining and degradation using scanning electron microscopy. Finally, 11 inter simple sequence repeats (ISSR) primers were used to evaluate the genetic polymorphism among Trichoderma strains, which yielded 133 bands with fragment sizes of 130-3400 bp, 47 (35.3%) of which were polymorphic. Interpretation: The current study confirms the existence of several useful Trichoderma strains with the highest chitinase activity and antagonistic activity against some pathogenic plant fungi that may have a super potential for application in biological control of plant diseases.

2010 ◽  
Vol 10 ◽  
pp. 760-765 ◽  
Author(s):  
S. C. Sati ◽  
P. Arya

The antagonistic activity of five aquatic hyphomycetes, viz.,Heliscus lugdunensis,Tetrachaetum elegans,Tetracladium breve,T. marchalianum, andT. nainitalense, against seven plant pathogenic fungi was studied using a dual culture technique. Inhibitory activity of tested aquatic hyphomycetes was determined by measuring the radial growth of plant pathogenic fungi on dual culture plates.Tetrachaetum elegansshowed antagonistic activity againstColletotrichum falcatum,Fusarium oxysporum,Pyricularia oryzae,Sclerotium sclerotiorum, andTilletia indicaHeliscus lugdunensisshowed antagonism against only two plant pathogenic fungi,Rhizoctonia solaniandColletotrichum falcatum.Tetracladium breve,T. marchalianum, andT. nainitalenseshowed no response towards tested plant pathogenic fungi.


Author(s):  
H.V. Parmar ◽  
N.M. Gohel

Background: Chickpea wilt complex caused by several soil-borne pathogens is the major yield-reducing malady worldwide. Biological control is one of the best, low-cost and ecologically sustainable method for managing plant diseases caused by soil-borne pathogens. Methods: In this present investigation Panchagavya and Trichoderma spp. were evaluated by following poisoned food technique and dual culture technique against wilt complex causing pathogens i.e. Fusarium oxysporum f. sp. ciceri, Fusarium solani and Macrophomina phaseolina. Result: Among the different isolates of Trichoderma spp. evaluated, Trichoderma viride (AAU isolate) was highly antagonistic to F. oxysporum f. sp. ciceri (52.78%) and F. solani (65.37%) whereas, Trichoderma asperellum (AAU isolate) was highly antagonistic to M. phaseolina (65.93%). Panchagavya at the highest concentration (50%) showed significantly higher efficacy (80.74, 66.62 and 49.67%) in inhibiting the mycelial growth of all three pathogens and at the lowest concentration it was moderately effective.


2014 ◽  
Vol 40 (3) ◽  
pp. 212-220 ◽  
Author(s):  
Sinar David Granada García ◽  
Antoni Rueda Lorza ◽  
Carlos Alberto Peláez

Microorganisms for biological control are capable of producing active compounds that inhibit the development of phytopathogens, constituting a promising tool toob tain active principles that could replace synthetic pesticides. This study evaluatedtheability of severalpotentialbiocontrol microorganismsto produce active extracellular metabolites. In vitro antagonistic capability of 50 bacterial isolates from rhizospheric soils of "criolla" potato (Solanum phureja) was tested through dual culture in this plant with different plant pathogenic fungi and bacteria. Isolates that showed significantly higher antagonistic activity were fermented in liquid media and crude extracts from the supernatants had their biological activities assessed by optical density techniques. Inhibitory effecton tested pathogens was observed for concentrations between 0.5% and 1% of crude extracts. There was a correlation between the antimicrobial activity of extracts and the use of nutrient-rich media in bacteria fermentation. Using a bioguided method, a peptidic compound, active against Fusarium oxysporum, was obtained from the 7ANT04 strain (Pyrobaculum sp.). Analysis by nuclear magnetic resonance and liquid chromatography coupled to mass detector evidenced an 11-amino acid compound. Bioinformatic software using raw mass data confirmed the presence of a cyclic peptide conformed by 11 mostly non-standard amino acids.


2021 ◽  
Vol 12 (2) ◽  
pp. 1143-1150
Author(s):  
Lavanya J ◽  
Chanthosh S ◽  
Reshma Shrii ◽  
Viknesh V ◽  
Deepika S ◽  
...  

The study was aimed to find an alternate approach for chemicals used in agriculture to avoid microbial infections. Fungal pathogens cause different types of plant diseases and affect a majority of edible crops by destroying the tissues of the plant in a direct or indirect mechanism. So, an alternative approach led to the development of biocontrol agents using endophytic  bacteria. A total of 8 endophytic bacteria were isolated from the root, stem, and leaves of radish (Raphanus sativus). The antagonistic activity of these bacteria against the 2 isolated plant pathogenic fungi was determined in vitro. Two out of eight bacteria showed more than 50% inhibitory activity against one fungus, were further characterized using the 16s rRNA sequencing method. On the basis of the phylogenetic tree of the 16s rRNA method, the endophytic bacterial samples were identified as Tonsilliphilus suis  and Exiguobacterium aurantiacum against plant pathogenic Aspergillus flavus  isolated from Raphanus sativus, which makes them highly suitable as an alternative for chemical fertilizers to provide resistance to plant pathogenic fungi. The cell wall degrading activities such as protease activity, amylase activity, and plant growth-promoting properties such as Hydrogen cyanide (HCN), Indole acetic acid (IAA), ammonia production of these endophytic bacteria were evaluated. The results show that T. suis  is the most effective strain for radish growth development.


Plant Disease ◽  
2009 ◽  
Vol 93 (10) ◽  
pp. 1037-1043 ◽  
Author(s):  
Young-Ki Jo ◽  
Byung H. Kim ◽  
Geunhwa Jung

Silver in ionic or nanoparticle forms has a high antimicrobial activity and is therefore widely used for various sterilization purposes including materials of medical devices and water sanitization. There have been relatively few studies on the applicability of silver to control plant diseases. Various forms of silver ions and nanoparticles were tested in the current study to examine the antifungal activity on two plant-pathogenic fungi, Bipolaris sorokiniana and Magnaporthe grisea. In vitro petri dish assays indicated that silver ions and nanoparticles had a significant effect on the colony formation of these two pathogens. Effective concentrations of the silver compounds inhibiting colony formation by 50% (EC50) were higher for B. sorokiniana than for M. grisea. The inhibitory effect on colony formation significantly diminished after silver cations were neutralized with chloride ions. Growth chamber inoculation assays further confirmed that both ionic and nanoparticle silver significantly reduced these two fungal diseases on perennial ryegrass (Lolium perenne). Particularly, silver ions and nanoparticles effectively reduced disease severity with an application at 3 h before spore inoculation, but their efficacy significantly diminished when applied at 24 h after inoculation. The in vitro and in planta evaluations of silver indicated that both silver ions and nanoparticles influence colony formation of spores and disease progress of plant-pathogenic fungi. In planta efficacy of silver ions and nanoparticles is much greater with preventative application, which may promote the direct contact of silver with spores and germ tubes, and inhibit their viability.


2020 ◽  
Vol 14 (1) ◽  
pp. 70-77
Author(s):  
Ziyaul Haque ◽  
Mohammed S. Iqbal ◽  
Ausaf Ahmad ◽  
Mohd S. Khan ◽  
Jyoti Prakash

Objective: In the present investigation, Trichoderma spp., isolated from rhizospheric soil, has been identified by Internal Transcribed Spacer (ITS) region sequencing technique and its antagonistic activity was evaluated against A. niger. Methods: The sequencing analysis was done with its ITS1 region of the rRNA gene. Using the ITS1 amplified products for all isolated fungi, a bi-directional DNA sequencing was done with high quality bases (>98% - 100%). Antagonistic activity was done using dual culture technique. Results: All of the ITS1 nucleotide sequences obtained in this study matched 97% - 100% with the published sequence of Trichoderma spp. The results confirmed the strains as T. asperellum and T. viride with gene bank accession no. (ZTa); MK937669 and (ZTv); MK503705, respectively. When phylogenetic analysis was done for the isolates, the optimal tree with the sum of branch length = 0.69585023 and 0.10077756 for T. asperellum and T. viride, respectively, was observed. There were a total of 678 and 767 for T. asperellum and T. viride positions in the final dataset, respectively. Antagonistic activity was done for the isolated strains of Trichoderma spp. against A. niger, and it was found that T. asperellum showed maximum antagonistic activity (79.33±7.09%). Conclusion: The findings prolong the genome availability for relative investigations pointing out phenotypic variances to compare with Trichoderma genetic diversity. The present investigation delivered the Bases of future studies for better knowledge in understanding the complicated connections of Trichoderma spp. to be used as an effective biocontrol agent.


2020 ◽  
Vol 12 (12) ◽  
pp. 144
Author(s):  
M. E. N. Ferreira ◽  
C. F. Pinto ◽  
R. R. de Sena ◽  
J. G. de Mendoça Neto ◽  
C. R. Lobo ◽  
...  

Fungi are among the main agents of plant diseases, being responsible for major losses in agriculture. The control of these microorganisms carried out using chemical compounds and numerous cases of resistance have already been observed, which makes it necessary to search for alternative methods of management of these pathogens. Therefore, the aim of this study, to evaluate the antifungal potential in plants. Twenty-four (24) plant extracts were tested for their antifungal potential against five plant pathogenic fungi: Sclerotinia sclerotiorum (Ss), Stromatinia cepivora (Sc), Fusarium oxysporum (Fox), Colletotrichum gloesporioides (Cg) and Verticillium dahlia (Vd). For the evaluation of the fungicidal potential, plant extracts were prepared by liquefying the plants in distilled water. The extracts were incorporated into PDA (Potato-Dextrose-Agar) culture medium to a final concentration of 35% and autoclaved. Then, PDA discs colonized by the aforementioned fungi were added to the center of each plate with the respective treatments (plant extracts). When all control treatments (PDA medium without plant extract) had colonized the entire Petri dish, the diameters of the fungal colonies were measured to calculate the Mycelial Growth Inhibition Index (MGI). Tests showed that all these plant extracts have some antifungal activity, ranging from 0 to 100% inhibition. In general, extracts of basil, lavender, guaco, rue, toxic cassava and black plum were the ones that stood out, with MGIs above 50%. New studies are being conducted to evaluate the activity of plant extracts without autoclaving, inhibition of sclerotia formation, to determine the minimum inhibitory concentration, as well as other parts of plants like roots and seeds, mixtures of plant extracts and in vivo antagonism tests.


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