scholarly journals Antifungal activity, identification and biosynthetic potential analysis of fungi against Rhizoctonia cerealis

2021 ◽  
Vol 71 (1) ◽  
Author(s):  
Xingli Zhao ◽  
Peng Song ◽  
Dianyun Hou ◽  
Ziliang Li ◽  
Zhenjie Hu

Abstract Purpose Wheat sheath blight mainly infected by Rhizoctonia cerealis is one of the soil-borne fungal diseases of wheat worldwide and prevalent in major wheat growing areas in China at present. This study aimed to evaluate the antifungal activity of 163 endophytic fungi on R. cerealis. Antifungal strains were identified and their biosynthetic potential was analysed. Methods The antifungal activity of the strains was evaluated via dual-culture antagonism assay. The antifungal strains were identified on the basis of morphological characteristics and internal transcribed spacer gene sequencing. The polyketide synthases (PKSs) and nonribosomal peptide synthetase (NRPS) genes in antifungal strains were detected via specific amplification of chromosomal DNA. Result Twelve out of 163 fungal strains, including seven strains with matrix competition and five strains with antibiosis, were obtained. The twelve antifungal strains belonged to four genera: Alternaria, Ascochyta, Botryosphaeria, and Talaromyces. The inhibition rate of the seven strains with matrix competition was greater than 50%, with that of Botryosphaeria dothidea S2-33 being the highest at 84.6%. The inhibition zone of Talaromyces assiutensis R-03 amongst the five strains with antibiosis was the widest at up to 7 mm. Among the twelve antifungal strains, the strain S2-16 contained all the genes tested, five B. dothidea strains contained PKS-II and NRPS genes, two Alternaria alternata strains only contained PKS-II gene and the remaining four strains did not contain any. Conclusion Results demonstrated twelve potential strains for the biocontrol of wheat sheath blight. In particular, T. assiutensis R-03 was determined as a promising agent. The active substances secreted by antifungal strains may be produced by other biosynthetic pathways.

2021 ◽  
Author(s):  
Xing-li Zhao ◽  
Peng Song ◽  
Dianyun Hou ◽  
Ziliang Li ◽  
Zhenjie Hu

Abstract Purpose: Wheat sheath blight mainly infected by Rhizoctonia cerealis is one of the soil-borne fungal diseases of wheat worldwide and prevalent in major wheat growing areas in China at present. This study aimed to evaluate the antifungal activity of 163 endophytic fungi on R. cerealis. Antifungal strains were identified and their biosynthetic potential was analysed. Methods: The antifungal activity of the strains was evaluated via dual-culture antagonism assay. The antifungal strains were identified on the basis of morphological characteristics and internal transcribed spacer gene sequencing. The polyketide synthases (PKSs) and nonribosomal peptide synthetase (NRPS) genes in antifungal strains were detected via specific amplification of chromosomal DNA. Result: Twelve out of 163 fungal strains, including seven strains with matrix competition and five strains with antibiosis, were obtained. The 12 antifungal strains belonged to four genera: Alternaria, Ascochyta, Botryosphaeria and Talaromyces. The inhibition rate of the seven strains with matrix competition was greater than 50%, with that of Botryosphaeria dothidea S2-33 being the highest at 84.6%. The inhibition zone of Talaromyces assiutensis R-03 amongst the five strains with antibiosis was the widest at up to 7 mm. Among the 12 antifungal strains, the strain S2-16 contained all the genes tested, five B. dothidea strains contained PKS-II and NRPS genes, two Alternaria alternate strains only contained PKS-II gene and the remaining four strains did not contain any. Conclusion: Results demonstrated 12 potential strains for the biocontrol of wheat sheath blight. In particular, T. assiutensis R-03 was determined as a promising agent. The active substances secreted by antifungal strains may be produced by other biosynthetic pathways.


Horticulturae ◽  
2021 ◽  
Vol 7 (7) ◽  
pp. 198
Author(s):  
Hongbo Yuan ◽  
Bingke Shi ◽  
Tianxiang Huang ◽  
Zengqiang Zhou ◽  
Li Wang ◽  
...  

Valsa canker caused by Valsa pyri is one of the most destructive diseases of commercial pear. For the present analysis, 29 different endophytic fungal strains were isolated from the branches of a healthy pear tree. In dual culture assays, strain ZZ1 exhibited robust antifungal activity against all tested pathogens including Valsa pyri. Microscopic analyses suggested that following co-culture with ZZ1, the hyphae of V. pyri were ragged, thin, and ruptured. ZZ1 also induced significant decreases in lesion length and disease incidence on detached pear branches inoculated with V. pyri. ZZ1 isolate-derived culture filtrates also exhibited antifungal activity against V. pyri, decreasing mycelial growth and conidium germination and inhibiting V. pyri-associated lesion development on pear branches. These results suggest that the ZZ1 isolate has the potential for use as a biological control agent against V. pyri. The strain was further identified as Penicillium citrinum based on its morphological characteristics and molecular analyses. Overall, these data highlight a potentially valuable new biocontrol resource for combating pear Valsa canker.


2009 ◽  
Vol 14 (2) ◽  
pp. 219-255
Author(s):  
Alimuddin Ali

Actinomycetes are one of the most attractive sources of antibiotics and other biologically active substances of high commercial value. Actinomycetes have proved to be capable of biosynthesizing secondary metabolites bearing conspicuous structural diversity, which could be further enlarged by structure modification. The objective of this work was to isolate and characterize of actinomycetes were responsibility to biosynthesis of a compound as antifungal agent and parsial identifying of these substances based on TLCbioautography. The study was done by some steps activities i.e: Isolation of actinomycete, antifungal assay, extraction and examination of MIC and TLC-bioautography using fungal test.The result of these research revealed that a genera Streptomyces spp has majority of actinomycetes was obtained from sources of microbia (decompozing sagoo solid waste). Isolate AS0827 has two a different spots which as antifungal activity based on Rf values. MIC of antifungal subtances was obtained from the actinomycetes about 200 µg/mL.The genera was shown highest of inhibition zone from of all the genera was named isolate AS0827.


2021 ◽  
Vol 25 (1) ◽  
pp. 64
Author(s):  
Yeyet Nurhayati ◽  
Suryanti Suryanti ◽  
Arif Wibowo

Trichoderma spp. is a fungus widely used to control soil-borne pathogens, such as Rhizoctonia solani which is plant pathogenic fungi in widely host range, especially on rice. This research aimed to evaluate the ability of Trichoderma asperellum isolate UGM-LHAF against R. solani causing sheath blight disease of rice in vitro condition. Trichoderma sp. used in this research was obtained from The Biological Laboratory of Pakem, Yogyakarta, Indonesia, and Rhizoctonia sp. was obtained through isolation of diseased rice obtained from rice fields in Yogyakarta. The two isolates were characterized base on morphology and molecular identification based on ITS rDNA. The pathogenicity test of Rhizoctonia sp. was evaluated by adding four sclerotia of Rhizoctonia sp. near rice roots at 6 days after sowing. The in vitro test used dual culture and antifungal activity (0%, 10%, 25%, 50% culture filtrate of Trichoderma sp.) with three replicates of each treatment. Two isolates were identified as T. asperellum and R. solani. Sheath blight symptoms appeared after 12 days inoculation. In the in vitro test, T. asperellum isolate UGM-LHAF was able to inhibit the mycelial growth of R. solani (64.23% on dual culture and 68.5% on antifungal activity). This study suggests that T. asperellum isolate UGM-LHAF able to inhibit the growth of R. solani and can be a further potential candidate as a biocontrol agent against R. solani causing sheath blight disease of rice.


Author(s):  
Carmen Emilia PUIA ◽  
Daniela Andreea GRIGORESCU ◽  
Raluca Vasilica MICLEA

Cryphonectria parasitica  (Murr.) Bar [syn. Endothia parasitica (Murr. And.] (anamorf: Endothiella sp .) is the causal agent of chestnut bark disease or chestnut blight, disease which produced great damages throughout the world, for example, in Europe, the European chestnut tree ( Castanea sativa (P.) Mill) was heavily affected. Environmental concerns have focused attention on natural forms of disease control as an effective alternative to chemical pesticides. In the chestnut blight fungus, Cryphonectria parasitica deals with a natural form of biological control in which the virulence of a fungal pathogen is attenuated by an endogenous viral RNA genetic element- the hypovirulent strain. In our researches we picked samples of chestnut bark from different areas in Maramures county. We’ve isolated the fungus on PDA medium and we’ve studied the morphological characteristics of the usual virulent strain and we looked for a possible hypovirulent strain in order to study its capacity for biological control. The fungus develops in the bark and in cambium where forms a yellowish or brownish stroma and produces both conidia and ascospores. The pycnidia stromata break through the lenticels producing conidia and later in the same stroma develop the perithecia which produce ascospores. Both strains of the fungus were found in the research area. The hypovirulent strain had a slower development, showed no sporu lation and pigmentation “white cultural strain” and was tested in vitro for the capacity to convert the virulent isolates by dual culture tests.


2017 ◽  
pp. 201-207 ◽  
Author(s):  
Dragana Plavsic ◽  
Gordana Dimic ◽  
Djordje Psodorov ◽  
Dragan Psodorov ◽  
Ljubisa Saric ◽  
...  

Aromatic plants are one of the most important sources of biologically active secondary metabolites, which possess various antimicrobial characteristics. The aim of this work was to examine the effect of antifungal activities of mint and caraway essential oils against the selected fungi. Eight species of molds were selected for antifungal testing: Alternaria alternata, Aspegillus flavus, A. niger, A. versicolor, Eurotium herbariorum, Penicillium aurantiogriseum, P. chrysogenum and P. expansum. Testing of essential oils antifungal activity against the selected species was conducted using the disc diffusion method by adding mint and caraway essential oils (0.5, 1, 5, and 10 ?l per disc). Antifungal activity of essential oils was expressed by the diameter of inhibition zone (mm). The most powerful effect of mint essential oil was recorded against E. herbariorum, as its growth was completely inhibited by the quantity of 5 ?l. The weakest inhibitory effect was observed against P. chrysogenum (inhibition zone 13.67 mm) by the quantity of 10 ?l. The most powerful antifungal activity of caraway was observed against E. herbariorum as growth was completely inhibited by the quantity of 10 ?l. The weakest inhibitory effect was observed against A. niger (inhibition zone 28 mm) by the quantity of 10 ?l.


Author(s):  
ABDULAZIZ BASHIR KUTAWA ◽  
SALMAN SADA BAKORI ◽  
HABU MUSA

Objective: The present study was carried out to determine the antifungal activity of Mangifera indica leaves extract on fungi isolated from bread vended within Bakori. Methods: The powdered form of M. indica leaves was used to prepare the extract using ethanol, the leaves were air dried at room temperature for 10 days. Results: The chemical test was carried out to identify the secondary metabolites, some of the metabolites that were present include alkaloids, saponins, flavonoids, steroids, and tannins. Both fungal isolates were identified on the basis of morphological characteristics as Aspergillus niger, Aspergillus flavus, and Mucor spp. The antifungal activity of M. indica leaves extract was determined using agar well diffusion method on Aspergillus and Mucor spp. The results showed that the extract was found to inhibit A. niger at 100 mg/ml, 50 mg/ml, and 25 mg/ml with 13.9 mm, 11.5 mm, and 8.0 mm, respectively, and A. flavus at 100 mg/ml, 50 mg/ml, and 25 mg/ml with 13.6 mm, 11.2 mm, and 8.1 mm, respectively, while Mucor spp. was found to be resistant at 25 mg/ml while 100 mg/ml and 50 mg/ml showed an activity. Minimum inhibitory concentration result showed a promising activity against Aspergillus spp. at 25 mg/ml while Mucor spp. at 50 mg/ml. Conclusion: Therefore, M. indica leaf extracts can be used in the treatment of diseases or illness caused by Aspergillus and Mucor spp.


2020 ◽  
Vol 110 (2) ◽  
pp. 317-326 ◽  
Author(s):  
Ayaz Farzand ◽  
Anam Moosa ◽  
Muhammad Zubair ◽  
Abdur Rashid Khan ◽  
Muhammad Ayaz ◽  
...  

Sclerotinia sclerotiorum is a devastating necrotrophic pathogen that infects multiple crops, and its control is an unremitting challenge. In this work, we attempted to gain insights into the pivotal role of lipopeptides (LPs) in the antifungal activity of Bacillus amyloliquefaciens EZ1509. In a comparative study involving five Bacillus strains, B. amyloliquefaciens EZ1509 harboring four LPs biosynthetic genes (viz. surfactin, iturin, fengycin, and bacilysin) exhibited promising antifungal activity against S. sclerotiorum in a dual-culture assay. Our data demonstrated a remarkable upsurge in LPs biosynthetic gene expression through quantitative reverse transcription PCR during in vitro interaction assay with S. sclerotiorum. Maximum upregulation in LPs biosynthetic genes was observed on the second and third days of in vitro interaction, with iturin and fengycin being the highly expressed genes. Subsequently, Matrix-assisted laser desorption/ionization-time of flight-mass spectrometry analysis confirmed the presence of LPs in the inhibition zone. Scanning electron microscope analysis showed disintegration, shrinkage, plasmolysis, and breakdown of fungal hyphae. During in planta evaluation, S. sclerotiorum previously challenged with EZ1509 showed significant suppression in pathogenicity on detached leaves of tobacco and rapeseed. The oxalic acid synthesis was also significantly reduced in S. sclerotiorum previously confronted with antagonistic bacterium. The expression of major virulence genes of S. sclerotiorum, including endopolygalacturonase-3, oxalic acid hydrolase, and endopolygalacturonase-6, was significantly downregulated during in vitro confrontation with EZ1509.


2011 ◽  
Vol 3 (1) ◽  
pp. 61-64
Author(s):  
Mohammad ANOWAR RAZVY ◽  
Ahmad Humayan KABIR ◽  
Mohammad AMINUL HOQUE

The antifungal activity of three varieties (red, green and wild) of water chestnut fruit extracts was studied against a number of fungal species. A strong antifungal activity of ethanol and petroleum extract was found against the treated fungi resulting remarkable inhibition zone in comparison to both Dithane-M45 fungicide and control. It has also been evident that wild variety of water chestnut was comparatively more efficient in respect to antifungal activity compared to the red and green variety of the same plant.


Toxins ◽  
2020 ◽  
Vol 12 (3) ◽  
pp. 152 ◽  
Author(s):  
Lucile Pellan ◽  
Noël Durand ◽  
Véronique Martinez ◽  
Angélique Fontana ◽  
Sabine Schorr-Galindo ◽  
...  

The aim of this study was to investigate the impact of commercialized biological control agents (BCAs) against two major mycotoxigenic fungi in cereals, Fusarium graminearum and Fusarium verticillioides, which are trichothecene and fumonisin producers, respectively. With these objectives in mind, three commercial BCAs were selected with contrasting uses and microorganism types (T. asperellum, S. griseoviridis, P. oligandrum) and a culture medium was identified to develop an optimized dual culture bioassay method. Their comportment was examined in dual culture bioassay in vitro with both fusaria to determine growth and mycotoxin production kinetics. Antagonist activity and variable levels or patterns of mycotoxinogenesis inhibition were observed depending on the microorganism type of BCA or on the culture conditions (e.g., different nutritional sources), suggesting that contrasting biocontrol mechanisms are involved. S. griseoviridis leads to a growth inhibition zone where the pathogen mycelium structure is altered, suggesting the diffusion of antimicrobial compounds. In contrast, T. asperellum and P. oligandrum are able to grow faster than the pathogen. T. asperellum showed the capacity to degrade pathogenic mycelia, involving chitinolytic activities. In dual culture bioassay with F. graminearum, this BCA reduced the growth and mycotoxin concentration by 48% and 72%, respectively, and by 78% and 72% in dual culture bioassay against F. verticillioides. P. oligandrum progressed over the pathogen colony, suggesting a close type of interaction such as mycoparasitism, as confirmed by microscopic observation. In dual culture bioassay with F. graminearum, P. oligandrum reduced the growth and mycotoxin concentration by 79% and 93%, respectively. In the dual culture bioassay with F. verticillioides, P. oligandrum reduced the growth and mycotoxin concentration by 49% and 56%, respectively. In vitro dual culture bioassay with different culture media as well as the nutritional phenotyping of different microorganisms made it possible to explore the path of nutritional competition in order to explain part of the observed inhibition by BCAs.


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