Yeasts are distributed in all environments and have been reported as potential biocontrol agents against various phytopathogenic fungi. To investigate their enzymatic and biological activities, 32 yeasts were isolated from 15 date vinegar samples. Evaluation of the antagonistic activities of isolated yeasts against the plant pathogens Fusarium oxysporium, Sclerotinia sclerotiorum, and Macrophomina phaseolina indicated that there are two yeasts had the highest inhibitory effect against plant pathogens, these yeasts identified as Kluyveromyces marxianus and Torulaspora delbrueckii using traditional and molecular methods. These yeast isolates were tested for fungal cell wall degrading enzymes (in vitro), and results indicated that the yeasts had strong protease and amylase enzyme activity and moderate chitinase and cellulase enzyme activity. The antagonistic activities of each yeast were evaluated using a dual culture technique. The results showed that K. marxianus inhibited the mycelial growth of F. oxysporium, S. sclerotiorum, and M. phaseolina by 70.5, 57.5, and 75.5%, respectively, whereas T. delbrueckii inhibited mycelial growth of F. oxysporum, S. sclerotiorum, and M. phaseolina by 55.3%, 66.2%, and 31.11%, respectively. The biofilm production assay indicated that the tested yeast could form biofilms as a mechanism of antagonistic activity against phytopathogenic fungi.
Twenty one isolates of lactose fermenting yeast were obtained from local yoghurt by using Davis's Yeast Salt agar which contained only the lactose as a carbon and energy source by following some initial cultured and microscopic tests. They had been subjected to qualitative and quantitative screening to choose the best isolate in biomass production. It was clear that isolates D1,D3,E3,F1,F2,F3 were have grown very slowly so they were ignored. The most rapid isolates have been selected for quantitative screening. Presence of lactose as the only carbon source had supply a selective pressure in reject yeasts that couldn’t consume lactose. Diagnostic results showed that the best isolate was Kluyveromyces marxianus, and marked with (A1)
... Show MoreResults showed that the optimum conditions for production of inulunase from isolate Kluyveromyces marxianus AY2 by submerged culture could be achieved by using inulin as carbon source at a concentration of 2% with mixture of yeast extract and ammonium sulphate in a ratio of 1:1 in a concentration of 1% at initial pH 5.5 after incubation for 42 hours at 30ºC.
The antiphytopathogenic effects of the crude methanol extract of Cladophora glomerata (Lin.) Kützing (Cladophoraceae) which isolated from Al Rashidiya region at north of Baghdad was investigated against two type of plant fungi (Pythium altimum and Rhizoctonia solani) which causes damping off disease where isolated from covered cucumber field in Al-Alyosifia region. Hot methanol extract showed antifungal activity against the two species of fungi in different concentrations(10,25,50 mg/ml) of extract to Cladophora glomerata as percentage inhibition (51.63 ,72.8 ,83.71) and (56.18 ,77.41 ,100)comparing with Pythium altimum and Rhizoctonia solani respectively .primary detection of active compounds showed that macroalgae (Cladoph
... Show MoreThis study was conducted in the College of Agriculture fields /University of Baghdad, during Autumn 2013. This study was aimed to examine the mortality rate on the all black fly stages of Acaudalerodes rachipora Singh) by the biotic fungus Beuveria bassiana. The results of a preliminary survey showed that the samples of Ziziphus spaina christi were infested by blakflies in Agriculture collage during Autumn seasons of 2013 , the presence of species of black flies A. rachipora on the lower surface of the leaf, the study aimed to study and research the effects of fungus B. bassiana on black fly A. rachipora. After six days of treatment results showed the continued superiority 106 spore / ml trends in the western, southern and
... Show MoreThe environment in Mosul city is very rich, containing a wide variety of microorganisms which have not been recognised for a long time. Five new fungal genes were identified and registered for the first time in the gene bank. These included Fusarium falciforme 2020-06-MIK-F1 genes for 5.8S rRNA with Accession no. LC555741, Nectriaceae sp. 2020-06-MIK-F2 genes for ITS1 with Accession no. LC555742, Trichoderma asperellum MIK3 genes for 5.8S rRNA with Accession no. LC575020, Penecillum sp. MIK4 genes for 5.8S rRNA with Accession no. LC575021, and Neurospora crassa MIK5 genes for 5.8S rRNA with Accession no. LC575022. These fungal genes were isolated from wastewater of Khosr river in Mosul city/ Iraq, whi
... Show MoreThis study was conducted to isolate and identify killer yeast Hanseniaspora uvarum from dates vinegar and measurement the ability of this yeast to produce killer toxin. The antimicrobial activity of the concentrated supernatant containing partially purified concentrated killer toxin was also detected against several pathogenic bacteria and yeast species, which includes two types of yeast Rhodotorula mucilaginosa and Candida tropicalis and four human pathogenic bacteria Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae and Pseudomonas aeurginosa. In addition, the antagonistic activity of examined yeast have been studied toward four types of fungi, where two are pathogenic
... Show MoreThe study aims to biosynthesized of sliver nanoparticle from aqueous extract of olive leave and evaluate the effectiveness of the synthesis AgNPs against isolated fungi. The study mediating fifty samples were taken from various tools in laboratory from five hospitals in Baghdad. Four species of fungi were identified depending on the morphological and microscopic characteristics. The most common isolated fungi based on their frequency ratio were as follows Aspergillus niger 87.5%, Aspergillus flavus 62.5%, Aspergillus fumigatus 53.5% and Aspergillus nidulans 37.7%.The Biosynthesis of silver nanoparticle developed a rapid, eco-friendly and convenient green method for the stable silver nanoparticles (AgNP
... Show MoreThis study is conducted to determine the effect of pathogenicity of the fungus Lecanicillium lecanii in some aspects of life of the insect saw toothed beetle Oryzaephilus surinamensis L. (Coleoptera: Silvanidae) under laboratory conditions with three concentrations of spores and mildew commentator (1 × 103, 1 × 105, 1 × 107) spore / ml , on eggs and larvae second phase of the insect .The study also includs the effect of the fungus concentrations of germination on rice (jasmine) by using direct spray treatment. The results show great fungus efficiency in the control of some aspects of life of the insect, where varied efficiency depends on the concentration of spores, The highest percentage loss of eggs is 63.33% at a concentration
... Show MoreThe current study aimed to assess the biological efficacy of the triple arbuscular mycorrhiza (AM) mixture of fungi Glomus etunicatum, G. leptotichum and Rhizophagus intraradices, and mix it with organic matter (O) and pathogenic fungi Fusarium oxysporum f.sp.lycopersici by using voyeurism in the plastic house in the growth of the tomato plant after four and eight weeks of cultivation. The results were shown after the treatment of the tomato plant in agriculture with the mixture of mycorrhiza and the pathogenic fungi and organic matter were treated with the mixture of mycorrhiza, organic matter and pathogenic fungi together. The effect of mycorrhiza and organic matter interference on the increase in the percentage of the lignin afte
... Show MoreThe present study was conducted to reveal the effect of crude oil on some fungal species isolation from soil in order to evaluate the role of these fungi in environmental balance of soil . The results showed a variation in numbers and percentage of the fungal isolates Aspergillus fumigatus dominated over all isolates with a frequency of (32.47) . In respect of the effect of different concentrations of the crude oil, low concentrations (0.05, 0.1) % showed no effect on radial growth ( mean colony diameter) of the isolated fungi grown &nbs
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