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Actinomycetes isolated from medicinal plant rhizosphere soils: diversity and screening of antifungal compounds, indole-3-acetic acid and siderophore production

Khamna, Sutthinan, Yokota, Akira, Lumyong, Saisamorn
World journal of microbiology & biotechnology 2009 v.25 no.4 pp. 649-655
Actinomadura, Alternaria brassicicola, Corticium rolfsii, Curcuma mangga, Fusarium oxysporum, Microbispora, Micromonospora, Nocardia, Penicillium digitatum, Streptomyces, agar, antifungal agents, indole acetic acid, medicinal plants, plant pathogenic fungi, rhizosphere, screening, siderophores, soil
A total of 445 actinomycete isolates were obtained from 16 medicinal plant rhizosphere soils. Morphological and chemotaxonomic studies indicated that 89% of the isolates belonged to the genus Streptomyces, 11% were non-Streptomycetes: Actinomadura sp., Microbispora sp., Micromonospora sp., Nocardia sp, Nonomurea sp. and three isolates were unclassified. The highest number and diversity of actinomycetes were isolated from Curcuma mangga rhizosphere soil. Twenty-three Streptomyces isolates showed activity against at least one of the five phytopathogenic fungi: Alternaria brassicicola, Collectotrichum gloeosporioides, Fusarium oxysporum, Penicillium digitatum and Sclerotium rolfsii. Thirty-six actinomycete isolates showed abilities to produce indole-3-acetic acid (IAA) and 75 isolates produced siderophores on chrome azurol S (CAS) agar. Streptomyces CMU-PA101 and Streptomyces CMU-SK126 had high ability to produced antifungal compounds, IAA and siderophores.