关键词: 烟草, 内生真菌, 分类鉴定, 乙酸乙酯提取物, 甲醇提取物, 抗细菌活性

Abstract: A total of 38 endophytic fungal isolates were separated from the healthy roots and stems of tobacco (Nicotiana tabacum), and 23 representative fungal isolates were selected for further identification by morphology features and ITS-rDNA analysis.Among 18 genera obtained, Acremonium (isolates Nitaf01 and Nitaf02), Fusarium (isolates Nitaf07,Nitaf08 and Nitaf09), Plectosphaerella (isolates Nitaf11 and Nitaf12) and Penicillium (isolates Nitaf18 and Nitaf20) were dominant genera.13 genera,namely Acremonium, Cladosporium, Clonostachys, Ilyonectria, Mortierella, Myriodontium, Petriella, Plectosphaerella, Podospora, Purpureocillium, Rhizopycnis, Stephanonectria and Thielavia were isolated from N.tabacum for the first time.Both mycelia and filtrate extracts of five fungal isolates (Colletotrichum sp.Nitaf05, Fusarium sp.Nitaf07, Purpureocillium sp.Nitaf13, Penicillium sp.Nitaf20 and Rhizopycnis sp.Nitaf22) showed strong antibacterial activity.The results demonstrated a diversity of the endophytic fungi in N.tabacum. These endophytic fungi had potential to produce antimicrobial compounds as well as to be used as the biocontrol agents.

Key words: Nicotiana tabacum, endophytic fungi, taxonomic identification, ethyl acetate extracts, methanol extracts, antibacterial activity