Fungal endophytes in Paeonia lactiflora and their secondary metabolites

Abstract:

[Objective] To explore the biosynthetic potential of endophytic fungi isolated from medicinal plants Paeonia lactiflora, we studied their population diversity and detected richness of their putative polyketide synthase (PKS) and nonribosomal peptide synthetase (NRPS) gene sequences.[Methods] Culture-dependent method was used to obtain endophytes from the surface-sterilized plant samples. Endophytes were identified based on morphological characteristics and ITS gene phylogenies. PKS and NRPS gene fragments were PCR amplified from genomic DNA with degenerate primers. The biosynthetic potential of endophytes was accessed by bioinformatic and phylogenetic analyses of PKS and NRPS gene sequences.[Results] A total of 105 endophytic isolates were isolated from P. lactiflora root tissues, yielding a total of 52 endophytic fungi through dereplication. The analysis results of endophtytic fungi ITS gene sequences showed that they affiliated to 15 genera of 13 families in seven orders, and Leptosphaeria, Ilyonectria and Fusarium were the predominant genera. Thirteen PKSs and eight NRPSs gene fragments were detected in a total of 52 endophytic fungi. Some fungi amino acid translated fragments were similar to sequences of PKS and NRPS involved in the biosynthesis of the antifungal compound in GenBank. Analysis of the detected endophyte gene fragments afforded consideration of the possible bioactivity of the natural products produced by endophytes from P. lactiflora.[Conclusion] This study demonstrated that the endophytic fungi from P. lactiflora roots had great significant diversity and potential to synthesize bioactive secondary metabolite, therefore, their natural products are worth of further research and development.