| Endophytic fungi are a group of fungi that colonize living,internal tissues of plants,of which an estimate of at least 1 million species.Because of what appears to be their contribution to the host plants,the endophytes may produce some a plethora of substances of potential use to the modern medicine,such as antimicrobial,antitumor and antioxidation compounds.Viola yedoensis Makino,a famous traditional Chinese medicine,has antibacterial and anti-inflammatory effect.However,study of the distribution characteristics of endophytic fungi from Viola yedoensis Makino were in the blank stage.The aim of this study was to investigate qualitatively and quantitatively the biodiversity of endophytic fungi from Viola yedoensis Makino.Furthermore,we explored and dicussed the antibacterial activity of endophytic fungi from Viola yedoensis Makino.The results obtained were as follows:1.1,058 strains of endophytic fungi were isolated from 1,532 tissue segments of Viola yedoensis Makino.1,058 strains finally were identified as 46 strains by morphological observation and 5.8S rDNA-ITS sequence analysis,which classified into 12 genera.Colletotrichum sp.and Fusarium sp.were dominant genera in endophytes from Viola yedoensis Makino,which occupied 36.86% and 25.05% of the all strains,respectively.2.556 endophytic fungi were isolated from roots,173 endophytic fungi were isolated from stems,268 endophytic fungi were isolated from leaves and 62 endophytic fungi were isolated from seeds.Nine genera were isolated from the root,eight genera were isolated from the leaves,and five genera were isolated from the stems and seeds,respectively.Fusarium sp.(43.88%)was dominant genus in the roots.Colletotrichum sp.was dominant genus in the the stems,leaves and seeds,which accounted for 60.69%,54.85% and 22.58%,respectively.Some fungi had tissue specificity,for example,Paramyrothecium sp.was isolated from the roots,Glomerella sp.was isolated from the leaves and Leptosphaerulina sp.was isolated from the seeds.188 strains were isolated from Viola yedoensis Makino in spring,462 strains were isolated in summer and 408 strains were isolated in autumn.Colletotrichum sp.was dominant fungi in spring,summer and autumn.3.The diversity indices of the endophytic fungi harvested in root were higher than those in the other three tissues,and the diversity indices in seeds were the lowest.Evenness index from roots,stems,and leaves were the similarity(0.95),evenness index from seeds was the lowest(0.79).The diversity analysis result of the fungi isolated from different seasons indicated that the difference of Shannon-Wiener diversity index and Margalef index in summer were the highest,followed by spring and autumn.While evenness index from autumn was the highest(2.07),followed by summer(1.90)and spring(0.28).4.10 strains of endophytic fungi had the remarkable inhibition to Bacillus cereus,with VM-32 high sensitivity.7 strains had antibacterial activity against S.agalactiae,with penicillin high sensitivity.11 strains had the inhibition to Staphylococcus aureus,with VM-8,VM-28 and VM-34 high sensitivity.VM-8,VM-9,VM-14,VM-25,and VM-33 had the inhibition to the three bacteria.But these endophytes were not against gram-negative bacteria. |
