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ISOLATION AND IDENTIFICATION OF TRICHODERMA SPECIES FROM SOILS FOR USING AGAINST SOME SOILBORNE FUNGAL PATHOGENS
2019
Nada Abd El-Aziz | A. Abd El-Razek | S. Ibrahem
Hydrolytic enzyme producing Trichoderma species have long been recognized as an agent for controlling plant diseases caused by various phytopathogenic fungi. A study was done to characterize four isolates of Trichoderma isolated from the rhizosphere of different crop plants to characterize and identify certain biocontrol related enzymes (β1,3-glucanase and chitinase). Morphological and molecular characterize action of antagonistic ability of Trichoderma species were studied. On the basis of morphological and culture characteristics, the Trichoderma isolates were identified as T. harizanum (1 isolate), T. viride (3 isolates). These isolates were tested against plant pathogens (Rhizoctonia solani, Pythium and Fusarium oxysporum). The best isolate producing chitinase (overproduction) was T. harizanum from (160 to 0.64) mg/ml. On the other hand the best isolate gave over production β-1; 3-glucanase over production was T. viride from (2250 to 2.20 mg/ml)
Afficher plus [+] Moins [-]BIOLOGICAL CONTROL OF SOIL -BORNE FUNGAL PATHOGENS
2019
Magdy Madkour | M. Afifi | E. Metry | I. Ismail
Seventeen bacterial isolates have been successfully isolated and purified from soil rhizosphere samples collected from different agricultural areas Buhayra, Sharqia and Alqilyubia of Egypt, and screened for production of chitinase enzymes had the highest chitinolytic activities amongst those investigated. Isolate S3-C and S1-C were Identified by biochemical, physiological tests and 16s rRNA gene primer as Bacillus cereus S3C, Gene Bank NCBI accession MK185696 and Bacillus cereus S1C accession MK185697. The production of chitinase by B.cereus S3C and Bacillus cereus S1C was optimized using colloidal chitin medium amended with 1% colloidal chitin at 30°C after five days of incubation. B.cereus S3C had potential for cell wall lysis of many phytopathogenic fungi tested such as Fusarium oxysporum and Rhizoctonia solani Potato phytopathogenic fungi by in vitro antagonistic test. The addition of B. cereus S3C chitinase was more effective than that of B.cereus S1C in increasing the resistance of Potato plants infected with various Soil- borne phytopathogenic fungi.
Afficher plus [+] Moins [-]ENDOPHYTIC BACTERIA ASSOCIATED WITH SUGARCANE AND ITS POTENTIAL TO SUPPRESS SPORISORIUM SCITAMINEUM, THE CAUSAL FUNGAL PATHOGEN OF SMUT DISEASE
2019
Shadia Taghian | Afaf El-Meneisy | A. Esh | N. Abdel-Ghaffar
Bacterial endophytic ubiquitously colonize the internal tissues of the plant. The purpose of this study was to isolate and identify the endophytic bacteria from sugarcane stalks which have antagonistic activity against Sporisorium scitamineum, the causal pathogen of sugarcane smut disease, and to study their activity to produce some secondary metabolites i.e. enzymes and growth-promoters. Sugarcane samples were collected from five governorates in Upper-Egypt namely, Giza, Beni-Suef, Sohag, Qena, and Luxor. A total of 240 isolates of endophytic bacteria were isolated from 160 samples of healthy sugarcane stalks (variety GT-54-9). Isolated endophytes were screened for its antagonistic activity against S. scitamineum, in vitro, using dual culture method. Only, 62 isolates showed different degrees of antagonistic activity. Ten isolates of endophytic bacteria were selected to study their potential to produce enzymes (chitinase, β 1,3 glucanase, phenylalanine ammonia lyase) and growth-promoters (siderophores, indole acetic acid (IAA), salicylic acid (SA)). These isolates were pre-identified using the morphological and physiological properties according to Bergy's manual as Pseudomonas sp., Serratia sp., Enterobacteria sp., Herbaspirillium sp., Gluconacetobacter sp. Anabaenopsis sp. and Azospirillumsp. All endophetic bacteria produced β 1,3gluconase and indole acetic acid (IAA), while Pseudomonas sp. produced salicylic acid and phenylalanine ammonia lyase, Ana baenopsis sp. produced phenylalanine ammonia lyase, Gluconacetobacter sp. produced chitinase and Herbaspirillium sp. produced siderophore. Meanwhile, isolates of Anabaenopsis sp. and Pseudomonas sp. were the most effective to produce β 1,3glucanase and indole acetic acid compared with other entophytic bacteria.
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