Production of lytic enzymes byTrichoderma spp. and their effect on the growth of phytopathogenic fungi

2002 ◽  
Vol 47 (3) ◽  
pp. 279-282 ◽  
Author(s):  
D. Witkowska ◽  
A. Maj
2018 ◽  
Vol 44 (3) ◽  
pp. 323-331
Author(s):  
Ozlem Oztopuz ◽  
Nermin Sarigul ◽  
Fakhra Liaqat ◽  
Ro-Dong Park ◽  
Rengin Eltem

Abstract Background Biological control of pathogenic fungi is a possible alternate to the chemical control, which is harmful to humans and environment. Soil-borne Bacillus strains can be potential biocontrol agents and a source of lytic enzymes. Aim This study aimed to examine biocontrol potential and lytic enzyme activities of a soil isolate Bacillus subtilis Ege-B-1.19. Materials and methods Strain was identified by biochemical and 16S rRNA gene analysis and its biocontrol activity was investigated against Aspergillus niger EGE-K-213, Aspergillus foetidus EGE-K-211, Aspergillus ochraceus EGE-K-217, Fusarium solani KCTC6328, Rhizoctonia solani KACC40111 and Colletotrichum gloeosporioides KACC40689. Chitinase, chitosanase, N-acetyl-β-hexosaminidase and protease activities of B. subtilis Ege-B-1.19 were also determined. Chitosanase was purified using Sephadex G-150 column and its molecular weight was determined by SDS-PAGE. Chitooligosaccharides production using chitosanase was carried out and analysed by TLC and HPLC. Results Results depicted that B. subtilis Ege-B-1.19 has shown inhibitory effects against all the test fungi. Chitinase, chitosanase, N-acetyl-β-hexosaminidase and protease activities were determined as 2.7 U mL−1, 7.2 U mL−1, 6.2 U mL−1 and 12.2 U mL−1, respectively. Molecular weight of purified chitosanase was 44 kDa. Chitosanase hydrolysed chitosan to glucosamine (GlcN), dimers (GlcN)2 and trimers (GlcN)3. Conclusion Bacillus subtilis Ege-B-1.19 can be anticipated as useful biocontrol agent and its chitosanase can be utilized for enzymatic synthesis of chitooligosaccharides.


2021 ◽  
Vol 10 (20) ◽  
pp. 32-38
Author(s):  
Oana-Alina Boiu-Sicuia ◽  
Vasilica Stan ◽  
Călina Petruța Cornea

Recycling the sewage sludge from treatment plants is a common activity. The resulting compost is usually rich in plant nutrients and beneficial microorganisms. However, compost properties greatly differ depending on the nature of the fermented biomass and fermentation processes. The aim of this study was to analyze the microbial load of three different composts, in order to detect new bacterial strains with plant protection properties. Isolated bacteria were microbiologically characterized and evaluated for their potential to reduce soil-borne phytopathogenic fungi. Results showed a microbial load of approximately 106 CFU/g of compost. In the analyzed samples it was revealed that as bacterial load increases, the fungal amount decreases. Analyzing some newly isolated bacteria obtained from these composts, a good biocontrol potential against soil-borne pathogenic fungi was revealed. Some of the isolated bacterial strains revealed antifungal activity against Rhizoctonia solani and Sclerotinia sclerotiorum. These bacteria showed good colonization capacity and lytic enzymes production, correlated to antimicrobial activity. These compost-originated bacteria reveal high potential in pathogens inhibition. Therefore, the analyzed composts are recommended not only as soil fertility improvers, but also as potential suppressors of soil-borne pathogens. Results revealed these composts as source of plant beneficial bacteria with biological control potential.


Author(s):  
Samah Abd El-Kader El-Debaiky ◽  
Anwer S.M. El-Badry

The antagonistic activity of Aspergillus piperis against Fusarium oxysporum f. sp. fabae (FOF) and Sclerotinia sclerotiorum were examined and showed multiple signs of hyphal interactions. Microscopic examination of contact regions among A. piperis and each pathogen revealed distinct enzymatic lysis of pathogenic hyphal cell walls. Therefore, it is important to estimate the lytic enzyme activity of A. piperis. Extracellular lytic enzymes are important offensive forces for A. piperis as a biological control agent. Chitinase, phospholipase, and protease recorded relatively high activity from a culture age of 10 days (82.3, 42.4, and 6.2 U/ml, respectively). Enzymatic persistence was measured at room temperature, recording relatively long periods, saving 54%, 46%, and 21% of their activity, respectively. The cytotoxicity of the crude culture filtrate of A. piperis was examined in MCF7 and WI38 human cell lines. The cell viability (IC50) value of the fungal filtrate was estimated after 24 h and 48 h. The results revealed that IC50 values against the MCF7 cell line were inoperative after 24 h and were recorded 80 μg/ml after 48 h. In contrast, IC50 values against the WI38 cell line were 85.69 and 69.8 μg/ml after 24 and 48 h, respectively.


2020 ◽  
Vol 27 (4) ◽  
pp. 329-336 ◽  
Author(s):  
Lei Xu ◽  
Guangmin Liang ◽  
Baowen Chen ◽  
Xu Tan ◽  
Huaikun Xiang ◽  
...  

Background: Cell lytic enzyme is a kind of highly evolved protein, which can destroy the cell structure and kill the bacteria. Compared with antibiotics, cell lytic enzyme will not cause serious problem of drug resistance of pathogenic bacteria. Thus, the study of cell wall lytic enzymes aims at finding an efficient way for curing bacteria infectious. Compared with using antibiotics, the problem of drug resistance becomes more serious. Therefore, it is a good choice for curing bacterial infections by using cell lytic enzymes. Cell lytic enzyme includes endolysin and autolysin and the difference between them is the purpose of the break of cell wall. The identification of the type of cell lytic enzymes is meaningful for the study of cell wall enzymes. Objective: In this article, our motivation is to predict the type of cell lytic enzyme. Cell lytic enzyme is helpful for killing bacteria, so it is meaningful for study the type of cell lytic enzyme. However, it is time consuming to detect the type of cell lytic enzyme by experimental methods. Thus, an efficient computational method for the type of cell lytic enzyme prediction is proposed in our work. Method: We propose a computational method for the prediction of endolysin and autolysin. First, a data set containing 27 endolysins and 41 autolysins is built. Then the protein is represented by tripeptides composition. The features are selected with larger confidence degree. At last, the classifier is trained by the labeled vectors based on support vector machine. The learned classifier is used to predict the type of cell lytic enzyme. Results: Following the proposed method, the experimental results show that the overall accuracy can attain 97.06%, when 44 features are selected. Compared with Ding's method, our method improves the overall accuracy by nearly 4.5% ((97.06-92.9)/92.9%). The performance of our proposed method is stable, when the selected feature number is from 40 to 70. The overall accuracy of tripeptides optimal feature set is 94.12%, and the overall accuracy of Chou's amphiphilic PseAAC method is 76.2%. The experimental results also demonstrate that the overall accuracy is improved by nearly 18% when using the tripeptides optimal feature set. Conclusion: The paper proposed an efficient method for identifying endolysin and autolysin. In this paper, support vector machine is used to predict the type of cell lytic enzyme. The experimental results show that the overall accuracy of the proposed method is 94.12%, which is better than some existing methods. In conclusion, the selected 44 features can improve the overall accuracy for identification of the type of cell lytic enzyme. Support vector machine performs better than other classifiers when using the selected feature set on the benchmark data set.


2019 ◽  
Vol 6 (02) ◽  
Author(s):  
AJAY KUMAR SINGH ◽  
AKHILESH KUMAR PANDEY

Natural phytotoxins of fungi are great source for the discovery of new herbicide and its offer a benign and eco-friendly alternative to manage weed. Thus, this study aimed to select potential fungi with potent herbicidal activity for control ofweeds. In the present study, various phytopathogenic fungi were isolated from infected tissues of various weeds and evaluated againstXanthium strumarium, a problematic monocotyledonous weed of open lands, agriculture, horticulture and forests. Herbicidal potential of Cell Free Culture Filtrate (CFCF) of strains ofPhoma herbarum (FGCCW#18, FGCCW#43) Fusariummonilifromecoded as FGCCW#35 and Fusarium roseum coded as FGCCW#55againstXanthium strumariumwere evaluated by seedling and shoot cut bioassays. Maximum mortalities of shoots, seedlings and phytotoxic damage were obtainedfrom28 day sold cell free culture filtrate (CFCF) of FGCCW#18 at 100% concentration. Significant reduction in biological contents i.e. photosynthetic pigment and protein was observed in the host weed on treatment with the CFCF as determined by detached leaf bioassay. Phytotoxic damage such as severe wilting, chlorosis, necrosis and complete collapse of the entire parts of the weed were also noticed due to CFCF application.


2021 ◽  
Vol 7 (5) ◽  
pp. 337
Author(s):  
Daniel Peterson ◽  
Tang Li ◽  
Ana M. Calvo ◽  
Yanbin Yin

Phytopathogenic Ascomycota are responsible for substantial economic losses each year, destroying valuable crops. The present study aims to provide new insights into phytopathogenicity in Ascomycota from a comparative genomic perspective. This has been achieved by categorizing orthologous gene groups (orthogroups) from 68 phytopathogenic and 24 non-phytopathogenic Ascomycota genomes into three classes: Core, (pathogen or non-pathogen) group-specific, and genome-specific accessory orthogroups. We found that (i) ~20% orthogroups are group-specific and accessory in the 92 Ascomycota genomes, (ii) phytopathogenicity is not phylogenetically determined, (iii) group-specific orthogroups have more enriched functional terms than accessory orthogroups and this trend is particularly evident in phytopathogenic fungi, (iv) secreted proteins with signal peptides and horizontal gene transfers (HGTs) are the two functional terms that show the highest occurrence and significance in group-specific orthogroups, (v) a number of other functional terms are also identified to have higher significance and occurrence in group-specific orthogroups. Overall, our comparative genomics analysis determined positive enrichment existing between orthogroup classes and revealed a prediction of what genomic characteristics make an Ascomycete phytopathogenic. We conclude that genes shared by multiple phytopathogenic genomes are more important for phytopathogenicity than those that are unique in each genome.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Yujing Liu ◽  
Zhang Song ◽  
Hualong Zeng ◽  
Meng Lu ◽  
Weiyao Zhu ◽  
...  

AbstractPseudomonas are ubiquitously occurring microorganisms and are known for their ability to produce antimicrobials. An endophytic bacterial strain NP-1 T, isolated from Eucalyptus dunnii leaves, exhibits antifungal properties against five tested phytopathogenic fungi. The strain is a Gram-negative rod-shaped bacterium containing a single polar flagellum. It is strictly aerobic, grows at 4–37 °C, 2–5% NaCl, and pH 3–7. The 16S rRNA sequence analysis showed that NP-1 T belongs to the Pseudomonas genus. Phylogenetic analysis based on four concatenated partial genes (16S rDNA, gyrB, rpoB and rpoD) and the phylogenomic tree indicated that NP-1 T belongs to Pseudomonas fluorescens lineage but is distinct from any known Pseudomonas species. The G + C mol % of NP-1 T genome is 63.96, and the differences between NP-1 T and related species are larger than 1. The digital DNA-DNA hybridization and tetranucleotide signatures are 23.8 and 0.97, which clearly separates strain NP-1 T from its closest neighbours, Pseudomonas coleopterorum and Pseudomonas rhizosphaerae. Its phenotypic and chemotaxonomic features confirmed its differentiation from related taxa. The results from this polyphasic approach support the classification of NP-1 T as a novel species of Pseudomonas, and the name of Pseudomonas eucalypticola is thus proposed for this strain, whose type is NP-1 T (= CCTCC M2018494T = JCM 33572 T).


2021 ◽  
Vol 3 (4) ◽  
Author(s):  
Ilgin Akpinar ◽  
Muammer Unal ◽  
Taner Sar

AbstractFusarium species are the primary fungal pathogen affecting agricultural foodstuffs both in crop yield and economic loss. Due to these problems, control of phytopathogenic fungi has become one of the critical problems around the World. Nanotechnology is a new technology with potential in many fields, including agriculture. This study focused on determining potential effects of silver nanoparticles (AgNPs) with different nanosizes (3, 5, 8 and 10 nm) and at different concentrations (12.5–100 ppm) against phytopathogenic Fusarium oxysporum f. sp. radicis-lycopersici (FORL) strains. The maximum antifungal activity was achieved by decreasing nanosize and increasing concentration of AgNPs. Mycelium growth abilities were decreased about 50%, 75% and 90% by AgNPs treatment with 3 nm sizes at 25 ppm, 37.5 ppm and 50 ppm concentrations, respectively. The productivity of fungal biomass in the liquid growth media was found to be too limited at the 25–37.5 ppm of AgNPs concentrations with all sizes. In addition, both septation number and dimensions of micro- and macroconidia were found to be gradually decreased with the application of silver nanoparticles. This work showed that the low concentration of AgNPs could be used as potential antifungal agents and applied for control of phytopathogens.


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