Antimicrobial Activity and Biodiversity of Endophytic Fungi in Dendrobium devonianum and Dendrobium thyrsiflorum from Vietman

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.

Antimicrobial activity of metabolites extracted from Zanthoxylum gilletii, Markhamia lutea and their endophytic fungi against common bean bacterial pathogens

“…Of all the Ascomycetes obtained, 71% of the fungal endophytes belonged to the genus Fusarium. These results correlate with those obtained from a study by Bai et al (2009), Chen et al (2010 and Xing et al (2011) which demonstrated that the dominant fungal endophyte strains isolated so far belong to the genus Fusarium. Although, Fusarium spp.…”

Cultural Endophytic Fungi Associated with <i>Dendrobium Officinale</i>:Identification, Diversity Estimation and their Antimicrobial Potential

“…Fungal diversity and richness in different tissues were measured and quantified using a variety of indices 14,18 , including species richness and evenness, Shannon's diversity and Simpson's diversity, dominance and Fisher's alpha diversity.…”

“…For the molecular identification, fungal genomic DNA was extracted from the mycelia using peqGOLD Fungal DNA Mini Kit (Peqlab, Erlangen, Germany). The internal transcribed spacer (ITS) region of rDNA genes was amplified using universal eukaryotic primers 14 : ITS1 (5-TCC GTA GGT GAA CCT GCG G-3) and ITS4 (5-TCC TCC GCT TAT TGA TAT GC-3). Standard PCR reactions were performed following the routine protocol and PCR products were directly sequenced.…”

In Vitro Multiplication of Aromatic and Medicinal Plants and Fungicide Activity

“…Drug resistance in fungi is increasing and is becoming a serious concern and the high use and misuse of antifungal as probably the main cause of this situation. Therefore, there is an urgent need to search for effective new antifungal agents in treatment of infectious diseases at present (Xing et al, 2011).…”