Isolation and identification of a taxol-producing endophytic fungus from Podocrapus
一株产紫杉醇罗汉松内生真菌的分离和鉴定

OBJECTIVE: Endophytic fungi can produce beneficial active components during symbiosis with host plants. We isolated a taxol-producing endophytic fungus strain from Podocrapus. METHODS: The anti-tumor activity of the endophytic funguswas detected by Methyl Thiazolyl Tetrazolium (MTT) method with Vero cells. The production of taxol by one fungus was confirmed by thin layer chromatography (TLC) and high performance liquid chromatography (HPLC). This strain was classified by morphology together with similarity of internal transcribed spacer (ITS) sequence by Clustal W method. The deduced apoptosis of taxol produced from the strain was detected by fluorescent staining method with Vero cells. RESULTS: A total of 155 endophytic fungi were isolated from the tissue of Podocrapus. The result showed that 28 strains inhibited the growth of Vero cell (inhibitory ratio > or = 10%), and 7 strains had high activity (inhibitory ratio > or = 70%). The taxol-producing ability of strain A2 was confirmed by TLC and HPLC. Therefore, we recognized strain A2 as an endophytic fungus capable of producing taxol from Podocrapus-1 and named it EPTP-1. Its output of taxol was 0.56 mg/L when growing in liquid potato dextrose medium. EPTP-1 was classified as Aspergillus fumigates. Taxol extracted from strain EPTP-1 resulted in significant apoptosis of Vero cells at concentration of 5.553 microg/L for 24h. The activity of anti-Vero growth by extracts from strain EPTP-1 was similar to that of the purchased standard taxol (P > 0.05). CONCLUSION: The identified endophytic fungus, strain EPTP-1, can be a candidate for taxol production.