Biocontrol Fungus

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  • Topic: Plant pathogens and diseases, Trichoderma, Fungus
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Mal.J. Microbiol. Vol 4(1) 2008, pp. 30-39

Fungal Control of Pathogenic Fungi Isolated From Some Wild Plants in Taif Governorate, Saudi Arabia Abou-Zeid A.M.*, Altalhi, A. D. and Abd El-Fattah, R.I Biology department, Faculity of Science, Taif University, Saudi Arabia. P.B. (888) E-mail: abouzeid_alaa@hotmail.com

ABSTRACT Twenty two plants were collected from Taif Governorate and identified as: Aerva lanata, Arnebia hispidissima, Artemisia judaica, Artemisia monosperma, Asphodelus aestives, Avena barbata, Capparis dcidua, Eucalyptus globulus, Euphorbia glomerifera, Foeniculum vulgare, Forsskaolea tenacissima, Juniperus procera, Launaea mucronata, Launaea sonchoides, Medicago sativa, Opuntia ficus, Phagnalon sinaicum, Prunus persica, Pulicaria crispa, Punica granatum, Rumex dentatus and Trichodesma calathiforme. Pathogenic fungi were isolated from some of these plants and identified as Alternaria alternata, Cephalosporium madurae, Cladosporium herbarum, Fusarium oxysporum, Humicola grisea, Penicillium chrysogenum and Ulocladium botrytis. Four antagonistic isolates were tested, 2 from Gliocladium fungus and 2 from Trichoderma fungus. We found that all the four antagonistic isolates (G. deliquescens, G. virens, T. viride and T. hamatum) significantly inhibited the radial growth of the pathogenic fungi tested, with different ratios. The results indicated that the antibiotics produced by the antagonists were more effective than the fungus itself and differ with different fungi. Coating plant stems with antagonists or with antagonist extracts reduce the severity of the disease but not prevent it in all tested pathogens. Keywords: pathogen, antagonist, antibiotic

INTRODUCTION Plant diseases play a direct role in the destruction of natural resources in agriculture. In particular, pathogens cause important losses, fungi being the most aggressive. Chemical compounds have been used to control plant diseases (chemical control), but abuse in their employment has favored the development of pathogens resistant to fungicides (Tjamos et al., 1992). By contrast, the use of microorganisms that antagonize plant pathogens (biological control) is risk-free when it results in enhancement of resident antagonists (Monte, 2001). Biological control of fungal plant pathogens appears as an attractive and realistic approach, and numerous microorganisms have been identified as biocontrol agents. A considerable role in limiting the populations of these pathogenic fungi inhabiting the aboveground parts of plants is played by antagonistic microorganisms. Such properties are first of all exposed by the fungi Trichoderma and Gliocladium (Massart and Jijakli, 2007; Sempere and Santamarina, 2007; Bartmanska and Dmochowska-Gladysz, 2006; El-Katatny et al., 2006; Patkowska, 2003; McQuilken et al., 2001; Roco and Perez, 2001; Ahmed et al., 2000; Harman, 2000; Kredics et al., 2000; Elad and Kapat, 1999; Gupta et al., 1999; Yedidia et al., 1999; Lumsden et al., 1992; Lifshitz et al., 1986). A general description of the vegetation of the western Saudi Arabia has been given by VeseyFitzgeraid (1957) and recognized a number of

vegetational and ecological types including littoral marshes, coastal desert plain, coastal foothills, mountain ranges and wadies. Batanouny (1979); Fayed and Zayad (1989); Mahmoud and El-Tom (1985) and Montealegre et al. (2000) described the vegetation of the Makkah-Taif roads and recognized a number of vegetational and ecological types mostly organized in zones. Referring to the western provinces (Saudi Arabia) flora. Batanouny and Baeshin (1978 and 1982) gave lists of 135 species belonging to 108 genera and 43 families of angiosperms along Jeddah-Makkah road. The distribution of species composition of each in specific ecologically defined habitats would substantiate the fact that such community types are useful as indicators for their habitat characters (El-Shourbagy et al., 1987), even under adverse conditions of disturbance...
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