scholarly journals Invitro Screening of Antifungal Activity of Rhizospheric Bacteria and Possible Role of Chitinase in Antifungal Activity

2012 ◽  
Vol 12 ◽  
pp. 304-311 ◽  
Author(s):  
Hari K Devkota ◽  
Bijaya L Maharjan ◽  
Bikash Baral ◽  
Anjana Singh ◽  
Kayo D Yami

The use of biocontrol agents is becoming an increasingly important alternative to chemical crop protection against weeds, insects and plant diseases in the field of agriculture. The success of biocontrol and yield increase depends on the nature of antagonistic properties and mechanisms of action of the biocontrol agent against the phytopathogens. In this study, 103 macroscopically different bacterial isolates (62 from Kirtipur and 41 from Khumaltar) from 21 different rhizosphere soil samples (11 from Kirtipur and 10 from Khumaltar) were screened for antagonism against five fungal phytopathogens, viz, Fusarium oxysporum, Alternaria solani, Sclerotium rolfsii, Exserohilum turcicum and Phytophthora infestans by dual culture technique on Potato dextrose agar. Out of 18 different active isolates two of them showed the chitinolytic potential and the most active fungal antagonist was identified as Bacillus subtilis on the basis of colonial, morphological, physiological and biochemical characteristics based on Bergey’s Manual of systemic bacteriology. The isolate produced maximum chitinase in colloidal chitin broth at pH7 and temperature 37oC after four days of inoculation. The corresponding culture filtrate supposed to contain chitinase showed maximum % inhibition of 53.29% with Fusarium oxysporum and no inhibition to Phytophthora infestans in agar well diffusion assay. Furthermore, chitinase was best fractionated at 40% ammonium sulphate salt fractionation which has almost similar inhibition potential as the crude culture filtrate. The 40% salt fraction of the enzyme showed the maximum chitinolytic potential at pH8 and temperature 40oC. Among the phytopathogens tested, sensitivity of Bacillus subtilis to fungi containing chitin on their cell wall demonstrates the possible role of chitinase in the antifungal activity.DOI: http://dx.doi.org/10.3126/njst.v12i0.6517 Nepal Journal of Science and Technology 12 (2011) 304-311 

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.


Agronomy ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1398
Author(s):  
Vishal Gupta ◽  
Krishna Kumar ◽  
Kausar Fatima ◽  
Vijay Kumar Razdan ◽  
Bhagwati Charan Sharma ◽  
...  

Saffron (Crocus sativus L.) is considered as one of the most expensive spices. Fusarium corm rot of saffron, caused by Fusarium oxysporum, is known to cause severe yield losses worldwide. In the present study, efficacy of biocontrol agents (Trichoderma asperellum, Pseudomonas fluorescens, Pseudomonas aeruginosa, Pseudomonas putida, Bacillus stratosphericus, Bacillus pumilus, and Bacillus subtilis) along with a chemical fungicide, carbendazim, was evaluated for managing the corm rot of saffron. Under in vitro conditions, using dual culture and poison food techniques on potato dextrose agar, T. asperellum and carbendazim significantly reduced the mycelial growth of the pathogen F. oxysporum, with the inhibition of 62.76 and 60.27%, respectively, compared with control. Under field conditions, dipping of saffron corms in carbendazim and T. asperellum exhibited maximum reduction of 82.77 and 77.84%, respectively, in the disease incidence, during the first year of experiment. However, during the second year, maximum reduction in the incidence of corm rot (68.63%) was recorded with the T. asperellum. Moreover, the population density of F. oxysporum was also significantly reduced by 60 and 80.19% while using T. asperellum after 75 and 260 days of sowing of saffron corms, compared to its population before planting of corms. In case of growth promotion traits, such as sprouting and flowering, biocontrol treatments reduced the number of days (average) of sprouting and flower emergence after sowing, compared to control.


2007 ◽  
Vol 53 (2) ◽  
pp. 207-212 ◽  
Author(s):  
Naveen Kumar Arora ◽  
Min Jeong Kim ◽  
Sun Chul Kang ◽  
Dinesh Kumar Maheshwari

A study was conducted to investigate the possibility of involvement of chitinase and β-1,3-glucanase of an antagonistic fluorescent Pseudomonas in growth suppression of phytopathogenic fungi, Phytophthora capsici and Rhizoctonia solani . Fluorescent Pseudomonas isolates GRC3 and GRC4 were screened for their antifungal potential against phytopathogenic fungi by using dual culture technique both on solid and liquid media. The percent inhibition was calculated. Various parameters were monitored for optimization of enzyme activities by fluorescent Pseudomonas GRC3. The involvement of chitinases, β-1,3-glucanases, and antifungal metabolites of nonenzymatic nature was correlated with the inhibition of P. capsici and R. solani. The results provide evidence for antibiosis as a mechanism for antagonism. The study also confirms that multiple mechanisms are involved in suppressing phytopathogens as evidenced by the involvement of chitinase and β-1,3-glucanase in inhibition of R. solani but not P. capsici by isolate GRC3.


Author(s):  
Akhilesh Kumar Kulmitra ◽  
Neha Sahu ◽  
V.B. Sanath Kumar ◽  
Thejesha A. G. ◽  
Amlan Ghosh ◽  
...  

The five different bio-agents viz., Trichoderma viride, T. harzianum, T. virens, Pseudomonas fluorescens and Bacillus subtilis were evaluated against Pyricularia oryzae at four and eight days after incubation through dual culture technique. Among the five different bio-agents, highest per cent inhibition of mycelial growth of fungus was recorded in T. virens i.e. 67 per cent and 70 percent after four and eight days after incubation respectively with mean of 68.5 per cent followed by Trichoderma viride with the inhibition of 61 and 63 per cent respectively with mean of 62 per cent. The Pseudomonas fluorescens did not show any inhibition of mycelial growth of P. oryzae as the pathogen over grew the bio-agents.


2003 ◽  
Vol 49 (4) ◽  
pp. 253-262 ◽  
Author(s):  
Yiu-Kwok Chan ◽  
Wayne A McCormick ◽  
Keith A Seifert

Bacteria were isolated from a cultivated soil and screened for antagonistic activity against Fusarium graminearum, a predominant agent of ear rot and head blight in cereal crops. Based on its in vitro effectiveness, isolate D1/2 was selected for characterization and identified as a strain of Bacillus subtilis by phenotypic tests and comparative analysis of its 16S ribosomal RNA gene (rDNA) sequence. It inhibited the mycelial growth of a collection of common fungal phytopathogens, including eight Fusarium species, three other ascomycetes, and one basidiomycete. The cell-free culture filtrate of D1/2 at different dilutions was active against macroconidium germination and hyphal growth of F. graminearum, depending on the initial macroconidium density. It induced the formation of swollen hyphal cells in liquid cultures of this fungus grown from macroconidia. A bioassay also demonstrated that D1/2 offered in planta protection against the damping-off disease in alfalfa seedlings caused by F. graminearum, while the type strain of B. subtilis was ineffective. Hence, B. subtilis D1/2 or its culture filtrate has potential application in controlling plant diseases caused by Fusarium.Key words: antifungal activity, Bacillus subtilis, biological control, biopesticide, Fusarium species.


Author(s):  
R. C. Osaro-Matthew ◽  
F. S. Ire ◽  
N. Frank-Peterside

Aim: The present study was carried out to isolate actinomycetes from rhizospheric soil of Curcuma longa and Zingiber officinale and evaluate their antifungal potential. Methods: Actinomycetes were isolated from the rhizosphere soil of two Zingiberaceae plants (Curcuma longa and Zingiber officinale), using four different culture media. Isolates were screened for antifungal activity using dual culture technique against two reference strains Colletotrichum coccodes (DSM 2492) and Alternaria pimpriana (DSM 62023). The most potent strain was identified based on 16S rRNA gene sequence and the bioactive components of the strain were identified using GC-MS chromatography. Results: Fifteen strains of actinomycetes were isolated, SCA (starch casein agar) was found best for cultivation of actinomycetes. The 15 strains were grouped into three genera Norcadia 8(54%), Streptomyces 5(33%) and Janibacter 2(13%) based on morphological, biochemical and physiological identification. Among the 15 isolates 6(40%) strains showed activity against either of the test organisms, while 1(6.7%) was active against the both test organisms. Comparative analysis of the 16S rRNA gene sequences identified the potent isolates as Janibacter sp. strain RC18. GC-MS analysis revealed the presence of 20 compounds with 10 identified as potent antimicrobial metabolites. Conclusion: This study has revealed that rhizosphere of ginger and turmeric harbours rare actinomycetes that are valuable tool for sustainable agriculture.


2021 ◽  
Vol 21 (no 1) ◽  
Author(s):  
K. Vignesh ◽  
K. Rajamohan ◽  
P. Balabaskar ◽  
R. Anandan

Tomato (Solanum lycopersicum L.) is one of the most important, commercial and widely grown vegetable crop in the world. Tomato plays a critical role in nutritional food requirements, income and employment opportunities for the people. However, its production is threatened by the Fusarium wilt caused by Fusarium oxysporum f.sp. lycopersici and production losses between 30%to40%. In the present investigation an attempt has been made to study the in vitro efficacy of Pseudomonas fluorescens against Fusarium oxysporum f.sp. lycopersici. The antagonistic effect of Pseudomonas fluorescens were observed by the Dual culture technique and Agarwell method under the in vitro conditions.Among the ten isolates of Pseudomonas fluorescens, isolate Pf5 found to show the maximum percent inhibition over control (58.75%) and least mycelial growth (37.12mm) in dual culture technique against Fusarium oxysporum f.sp. lycopersici. In Agar well method isolate Pf5 proved out the maximum inhibition zone (17.47mm)against Fusarium oxysporumf.sp. lycopersici and percent inhibition over control (80.97%) at 30% concentration level.


1994 ◽  
Vol 24 (11) ◽  
pp. 2235-2239 ◽  
Author(s):  
P. Chakravarty ◽  
L. Trifonov ◽  
L.J. Hutchison ◽  
Y Hiratsuka ◽  
W.A. Ayer

Interactions between Sporormiellasimilis Khan & Cain and the blue-stain fungus Ophiostomapiliferum (Fr.) H. & P. Sydow, both isolated from Populustremuloides Michx. wood, were investigated. Sporormiellasimilis significantly reduced the growth of O. piliferum in vitro when grown in dual culture, in addition to inhibiting the growth of O. piliferum on agar media and in liquid culture when treated with a culture filtrate of S. similis. Ophiostomapiliferum failed to colonize P. tremuloides wood chips when they were preinoculated with S. similis. Ten known compounds were isolated and identified from the culture filtrate of S. similis. These compounds showed varied fungitoxic effect against O. piliferum at concentrations of 1 to 1000 μg/mL. The potential for S. similis as a biological control agent against O. piliferum on P. tremuloides is discussed.


2016 ◽  
Vol 1 (02) ◽  
pp. 138-144
Author(s):  
Rashmi Nigam ◽  
A. K. Sharma ◽  
Joginder Singh

Plant growth promoting rhizobacteria (PGPR) are a heterogeneous group of bacteria that are found in the rhizosphere and rhizoplane which can improve plant growth. Pseudomonas spp. is one of the most promising groups of PGPR which can control plant pathogenic microbes in the soil. In this study, an attempt was made to isolate Pseudomonas spp., a potent PGPR in the rhizosphere. Through appropriate microbiological and biochemical methods, the study demonstrated the presence of fluorescent and nonfluorescent Pseudomonads in the rhizosphere of pea. 12 different strains of Pseudomonas were isolated from pea rhizosphere and identified by biochemical tests. Out of these strains five were screened against wilt and root rot pathogens of pea. Antagonistic activity of Pseudomonas isolates were evaluated against wilt and root rots pathogens i.e. Fusarium oxysporum, Rhizoctonia solani and Pythium ultimum through dual culture technique. The study exhibited that all Pseudomonas strains significantly inhibited the growth of Fusarium oxysporum, Rhizoctonia solani and Pythium ultimum as compared to control. Among all the Pseudomonas isolates Ps5 showed maximum inhibition against Fusarium oxysporum, Rhizoctonia solani and Pythium ultimum. Augmentation of such PGPR will ensure a healthy micro climate for pea.


2021 ◽  
pp. 466-478
Author(s):  
Mileidy Cruz Martín ◽  
Liliana Leyva ◽  
Mayra Acosta Suárez ◽  
Tatiana Pichardo ◽  
Idalmis Bermúdez Caraballoso ◽  
...  

Introduction. Due to the absence of totally effective either economically viable chemical agents for the control of Fusarium wilt, the use of antagonistic microorganisms is of great interest since it could represent a more economically and ecologically sustainable alternative. Objective. To analyze the antifungal effect of the Bacillus amyloliquefaciens CCIBP-A5 strain against Fusarium oxysporum. Materials and methods. The work was carried out in the Laboratory of Applied Microbiology of the Instituto de Biotecnología de las Plantas, Cuba, between September 2017 and June, 2018. The in vitro and in vivo antifungal activity of its culture filtrate and cell against F. oxysporum has been assayed. Results. The results indicated that the metabolites present in the culture filtrate of B. amyloliquefaciens CCIBP-A5 significantly influenced the growth and morphology of the mycelium and the conidia. They also caused oxidative damage to the lipid molecules of F. oxysporum. In addition, this strain showed inhibitory effects on the development of the disease under controlled conditions. These aspects are key when selecting a bacterial candidate as a biological control agent. Conclusions. The results showed that the B. amyloliquefaciens CCIBP-A5 strain, isolated from Musa sp., had an in vitro antifungal effect against the vegetative and reproductive structures of Foc race 1 as well as on the Musa spp.-F. oxysporum interaction. This strain is suggested for the development of a bioproduct for Fusarium wilt management.


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