Study On Diversity Of Fungi Community Associated With Three Corals In Xuwen And Antimicrobial Activities

Coral reefs exist as one of the most diverse ecosystems, but little information has beenknown about the microbes communities associated with corals. The complex of themicrobial communities are recognized to be important to the ecosystems and influence thecomposition of the ecosystems.Marine microbes have been proved to produce lots of novelbioactive products and take part in the biosyntheses of some marine secondary metabolitesisolated from marin organism hosts. Xuwen coral nature reserve is one well-reserved areafor corals reproducing and also the only one reserved completely area for corals growth.Little knowledge is known about the diversity of fungi associated with the corals in Xuwen.In this paper, we collected three samples of corals, isolated fungi from the coral andidentified the taxa of these fungi. Two medium was used for isolation of fungi associatedwith three corals samples, and with the agar diffusion method, the antimicrobial activitiesof these isolates were investigated.Cultivation of fungi from the tissue of the three sxleractinian corals yielded a total of54strains. All the isolates are under observation on morphological characteristics.Penicillium sp.and Aspergillus sp.are dominant morphotypes accounting for18.52%and29.63%of the total isolates respectively. And these two taxa are common on three corals,but the others are distinguish genera among the samples.All the strains were cultured for genomic DNA extracts and sequencing analysis.With the ITS-rDNA gene sequences, the NJ tree was built and all the strains from sampleswere analysed and compared with the ralated sequences from GenBank.54strains areclassified into3orders16families. Beside the dominent genera, few proportion of fungibelonged to Basidiomycete sp., Ttritirachium sp., Rigidoporus vinctus, Phellinus noxius,Lentinus sp., Didymellaceae sp. and Curvularia sp.. Of54isolates, there is one strain thesimilarity of one strain named as C1-23sequence to the most closed related sequences inGenBank was only90%, which is propably a new species.With two media of fermentation, antibacterial activities of all the strains wereinvestigated by agar difusion method to four pathogens.13strains displayed differentlevels of antibacterial activities, most of which showed growth inhibition to tested bacterialSarcina luteu and Staphylo-coccus aureus. The crude extracts of ethylacetate of fungishowed rather high antibaterial activities. Several fungi in the Aspergillus sp.,Hypocreaceae sp. and Acremonium sp.with strong inhibitory activities provide potentialfor further research on secondary metobolites.