Fungi Diversity In The Rhizosphere Of Rhizophora Stylosa And Construction A Composite Microbial System With Efficient Cellulose Degradation

Mangrove swamps are unique intertidal wetland ecosystems in tropical and subtropical shores, where contain diverse plant, animal and microorganisms resources. Mangrove ecosystem have three characteristic:high productivity, high decomposition rate and high return rate. There are many biomass resources,such as leaf litter. Special mangrove swamps niches possess valuable microorganisms. Many microbe can product cellulolytic enzyme, ligninolytic enzyme and other substances.In this research, the culture-dependent methods and culture-independent methods were constructed to investigate the fungi diversity in the rhizosphere of Rhizophora stylosa collected in Hongsha river,Sanya,Hainan Province and a congo red declocring method was also constructed to identify the cellulose degradation ability of the fungi. It will provide important information to some fields:such as the fungi’ distribution regularities in the mangrove swamps of our country, the function of fungi in biomass cycling, the effective using of microorganisms in the mangrove ecosystem and maintain the balance of biosphere.The PDA medium was used to isolate fungi from the sediment of Rhizophora stylosa, finally we got51colones of fung. Using the ITS gene sequencing method, they were classed as16well-known genera and1unknown genera, they are Nectria, Lecanicillium, Microsphaeropsis, Penicillium, Trichoderma, Hypocrea, Aspergillus, Fusarium, Eutypella, Colletotrichum, Arthrinium, Bipolaris, Trametes, Fomitopsis, Xylariaceae and Acremonium. The total DNA was isolated directly from sediment and a28S rDNA library was constructed to analyze the fungi diversity in the nature environment. According to the28S rDNA gene sequencing, we class the fungi to11known genera, such as Arachnomyces, Geomyces, Apiospora, Staninwardia, Aspergillus, Penicillium, Eupenicillium, Malassezia, Hypoxylon, Hamigera and Schizophyllum, while there are also9OTU that we can not class them to any know genus.Using the congo red declocring method, the cellulose degradation ability of all23species fungi were constructed.56.5%fungi can form clear zone on the congo red medium,them belong to10genera13species. The fungi whose CMCase activity above2.0, account for61.5%.The fungus Z-43has a hightest CMCase activity of3.79. Meanwhile, we also found4novel fungi, they are Xylariaceae sp.DPZ-SY43, Acremonium sp.DPZ-SYz-23, Hypoxylon.sp.DPZ-SYz-36and Aspergillus sp.Z-24.Finally, a composite microbial system with efficient cellulose-degrading capacity was constructed by the techniques of limitied and generation by generation cultivation.It was found that83.6%Bruguiera gymnorrhiza leaves,67.3%Rhizophora stylosa leaves and71.5%filter paper can be degraded by the composite microbial system at30℃within10days under static culture and the CMCase activity were102.2U/mL、110.7U/mL、126.3U/mL, respectively. The microorganism diversity of SYF was analysis by the plate screening method and clone library establishment method. Eight genera bacteria and3genera fungi were isolated from the composite microbial system. Meanwhile, six known genera and two unknown species microbial were detected by the16S rDNA libraries,5species fungi were detected by the ITS libraries. Only Just3genera were detected by the two methods. There were still many anaerobic and difficult culture bacterium existed in the composite microbial system. The composite microbial system expressed a higher bacteria diversity, so as to ensure its composite stability and collaborative cellulose-degrading capacity.