Authors: Ke Zhao Petri Penttinen Qiang Chen Tongwei Guan Kristina Lindström Xiaoling Ao Lili Zhang Xiaoping Zhang
Publish Date: 2012/01/28
Volume: 94, Issue: 5, Pages: 1321-1335
Abstract
Actinobacteria are a prolific source of antibiotics Since the rate of discovery of novel antibiotics is decreasing actinobacteria from unique environments need to be explored In particular actinobacterial biocontrol strains from medicinal plants need to be studied as they can be a source of potent antibiotics We combined culturedependent and cultureindependent methods in analyzing the actinobacterial diversity in the rhizosphere of seven traditional medicinal plant species from Panxi China and assessed the antimicrobial activity of the isolates Each of the plant species hosted a unique set of actinobacterial strains Out of the 64 morphologically distinct isolates half were Streptomyces sp eight were Micromonospora sp and the rest were members of 18 actinobacterial genera In particular Ainsliaea henryi Diels hosted a diverse selection of actinobacteria although the 16S ribosomal RNA rRNA sequence identity ranges of the isolates and of the 16S rRNA gene clone library were not congruent In the clone library 40 of the sequences were related to uncultured actinobacteria emphasizing the need to develop isolation methods to assess the full potential of the actinobacteria All Streptomyces isolates showed antimicrobial activity While the antimicrobial activities of the rare actinobacteria were limited the growth of Escherichia coli Verticillium dahliae and Fusarium oxysporum were inhibited only by rare actinobacteria and strains related to Saccharopolyspora shandongensis and Streptosporangium roseum showed broad antimicrobial activityThis research was supported by the foundation of National Science Program of China Project no 30570062 and Sichuan Provincial Science and Technology International Cooperative Project We sincerely acknowledge kind support from the Key Laboratory of Protection and Utilization of Biological Resources Tarim University and Key Laboratory of Marine Biogenetic Resources The Third Institute of Oceanography State Oceanic Administration when our laboratory was damaged by the 2008 Sichuan earthquake
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