title: Antimicrobial activity and biodiversity of endophytic fungi in Dendrobium devonianum and Dendrobium thyrsiflorum from Vietnam.
abstract: Endophytic fungi are rich in orchids and have great impacts on their host plants. 53 endophytes (30 isolates from Dendrobium devonianum and 23 endophytic fungi from D. thyrsiflorum) were isolated, respectively, from roots and stems of Dendrobium species. All the fungi were identified by way of morphological and/or molecular biological methods. 30 endophytic fungi in D. devonianum were categorized into 11 taxa and 23 fungal endophytes in D. thyrsiflorum were grouped into 11 genera, respectively. Fusarium was the dominant species of the two Dendrobium species in common. Antimicrobial activity of ethanol extract of fermentation broth of these fungi was explored using agar diffusion test. 10 endophytic fungi in D. devonianum and 11 in D. thyrsiflorum exhibited antimicrobial activity against at least one pathogenic bacterium or fungus among 6 pathogenic microbes (Escherichia coli, Bacillus subtilis, Staphylococcus aureus, Candida albicans, Cryptococcus neoformans, and Aspergillus fumigatus). Out of the fungal endophytes isolated from D. devonianum and D. thyrsiflorum, Phoma displayed strong inhibitory activity (inhibition zones in diameter >20 mm) against pathogens. Epicoccum nigrum from D. thyrsiflorum exhibited antibacterial activity even stronger than ampicillin sodium. Fusarium isolated from the two Dendrobium species was effective against the pathogenic bacterial as well as fungal pathogens. The study reinforced the assumption that endophytic fungi isolated from different Dendrobium species could be of potential antibacterial or antifungal resource.
authors.affiliation: Institute of Medicinal Plant Development, Chinese Academy of Medical Sciences & Peking Union Medical College, No. 151, Malianwa North Road, Haidian District, Beijing 100193, People's Republic of China.
authors.forename: Yong-Mei
authors.initials: YM
authors.lastname: Xing
authors.forename: Juan
authors.initials: J
authors.lastname: Chen
authors.forename: Jin-Long
authors.initials: JL
authors.lastname: Cui
authors.forename: Xiao-Mei
authors.initials: XM
authors.lastname: Chen
authors.forename: Shun-Xing
authors.initials: SX
authors.lastname: Guo
mesh_terms: D000900:Anti-Bacterial Agents / Q000378:metabolism* / Q000494:pharmacology; D001419:Bacteria / Q000187:drug effects; D044822:Biodiversity; D031667:Dendrobium / Q000382:microbiology* / Q000502:physiology; D005658:Fungi / Q000145:classification / Q000235:genetics / Q000302:isolation & purification / Q000502:physiology*; D008826:Microbial Sensitivity Tests; D008969:Molecular Sequence Data; D013559:Symbiosis; D014744:Vietnam
chemical_list: D000900:Anti-Bacterial Agents