Diversity,antifungal and antibacterial activity of endophytic fungi from Thespesia populnea
[Objective]To provide a reference for finding eco-friendly antibacterial agents,the diversity of endophytic fungi in the medicinal plant Thespesia populnea in mangroves and their antifungal and antibacterial activities were studied.[Method]Endophytic fungi were isolated and purified from the stem,leaf and bark tissues of the medicinal plant T.populnea in Guangxi Beibu Gulf mangroves,and identified by a combination of morphology and molecular biology.Colletotrichum from Diospyros kaki,Juglans regia,Litchi chinensis,and Fusarium oxyspo-rum f.sp.cubense 1(FOC1),Fusarium oxysporum f.sp.cubense 4(FOC4),and Alternaria cucumerina from Cucumis sativus,as well as en-dophytic fungus Alternaria alternata from Avicennia marina,and Streptococcus iniae from Oreochromis niloticus,were selected as indicator or-ganisms.The antifungal and antibacterial activities of endophytic fungal extracts were screened by plate confrontation method and filter paper method.[Result]A total of 60 strains of endophytic fungi were isolated and purified from T.populnea,belonging to 5 genera and 25 species.Among them,the genera Colletotrichum and Diaporthe were dominant,with the isolation rates of 48.33%and 26.67%,respectively.The rest were Botryosphaeria,Didymella and Cryptosporella,with isolation rates of 15.00%,6.70%and 3.33%respectively.The most strains were isolated from the bark tissue of T.populnea,with a total of 4 genera and 23 strains,accounting for 38.33%of the total isolation a-mount,followed by leaf tissue(31.67%)and stem tissue(30.00%).In addition,12 endophytic fungi were found to have ITS rDNA se-quence similarity of less than 95.00%with NCBI database,indicating that they might be potential new species.The results of antifungal and antibacterial activities indicated that J1-20 had strong antifungal and antibacterial activities against the 8 selected indicator organisms.The an-tifungal rates against Colletotrichum of D.kaki,Colletotrichum of J.regia,Colletotrichum of L.chinensis,FOC1 and FOC4,A.cucumerina from C.sativus,A.alternata from A.marina,were 39.39%,25.00%,19.10%,32.43%,28.20%,89.00%and 74.19%,respective-ly.Meanwhile,the inhibitory zone of Jl-20 against S.iniae was 21.00 mm.[Conclusion]The endophytic fungi in T.populnea have rich di-versity and relatively uniform distribution.Among them,J1-20 has broad-spectrum antifungal and antibacterial activities against 8 indicator organisms and has good development potentials.
Thespesia populneaEndophyte fungiDiversityAntifungal and antibacterial activity