Distribution and diversity of endophytic fungi in and cytotoxic activities.

OBJECTIVE

In the present study, was screened for fungi communities to clarify their diversity and community assemblage in hosts. Meanwhile, the identification and activity assays of the strains were also conducted.

METHODS

By culture-dependent (endophytic fungi isolations from plant sections) and culture-independent (metagenomic library and cloning from plant sections) techniques, fungi communities were studied. The metagenomic library was generated using direct DNA isolation of whole plants, plant radixes, plant stems, plant leaves, plant flowers and soils around the plant. Meanwhile, endophytes were isolated from all parts of plants. After fermentation of the fungi isolations, all the isolates were evaluated for their cytotoxicity against four kinds of human cancer cell lines (HCT116, BEL7404, A549, MDA-MB-231).

RESULTS

Eventually, 200 strains were isolated and 103 strains were further identified through the internal transcribed spacer (ITS, ITS1 and ITS2 regions) sequence by using the universal primers ITS5 and ITS4. A total of 59,106 fungal sequences corresponding to 374 putative operational taxonomic units (OTU) were identified by 454 pyrosequencing. Through 454 pyrosequencing, the main fungal genera were , , , and and the major fungal genera which were directly isolated were and . Activity assays showed strains 5-26 ( sp.) and 6-2 () had the outstanding cytotoxicity to all the tested cell lines with IC values <5 μg/mL.

CONCLUSION

This study revealed the abundance of endogenetic fungal resources and a variety of genetic information in by high-throughput 454 sequencing technology and fungi isolation methods. Activity assays indicated that endophytes were a promising natural source of potential anticancer agents.