[Genetic diversity and antibacterial activity of endophytic fungi from Zanthoxylum nitidum]

In order to reveal the distribution and population characteristics of endophytic fungi from Zanthoxylum nitidum and the antibacterial potential,this study performed molecular identification and analyzed the genetic diversity and antibacterial activity of endophytic fungi from Z. nitidum in Guangxi. Through culture and molecular identification,35 strains,belonging to 15 genera,12 families,10 orders,4 classes,and 2 phyla,were isolated from various tissues of Z. nitidum,of which Colletotrichum and Fusarium were the dominant genera,respectively accounting for 20% of total strains. The diversity of endophytic fungi was significantly different among roots,stems,and leaves,as manifested by the significantly higher Shannon index( H') in stems( 1. 678) than in roots( 0. 882 1) and leaves( 0. 515 4). The antimicrobial activity analysis showed that 14. 28% of endophytic fungi inhibited at least one indicator pathogen. Among them,Fusarium sp. ZN-34 and Fusarium sp. ZN-26 separately demonstrated the strongest inhibitory effect on Escherichia coli and Staphylococcus aureus. In general,Fusarium sp. ZN-26 and Phialemoniopsis plurioloculosa ZN-35 were advantageous in suppressing the two bacteria owing to the broad spectrum and strong efficacy. In summary,Z. nitidum in Guangxi boasts rich endophytic fungi with the majority showing strong antibacterial activity,which can be used as candidates for the extraction and separation of basic antibacterial substances and the development of natural antibacterial agents.