Study On The Diversity Of Blueberry Endophytic Fungi Resources And The Selection And Application Of High-efficiency Strains

Blueberry,listed as one of the five major human healthy food by FAO,is a new small berry tree with high economic value and broad prospect because of its high nutritional value and special health function,but the production isn’t meet the needs of market yet.In recent years,the blueberry industry develops rapidly in China,and the commercial cultivation area increasingly moves to the south with Guangdong province as an representative,where the temperature is high and the soil is infertile,which seriously restricts the development of the blueberry industry.At present,the mycorrhizal technology is used more and more in agriculture and forestry,the ecological and physiological function of mycorrhizal fungi,like enhancing plant resistance and the success rate of introduction,are significant,indicating that using mycorrhizal technology is a good way to improve the conditions of blueberry cultivation in Southern China.Therefore,taking blueberry endophytic fungi as the core,the separation and screening of endophytic fungi were conducted to reveal the diversity and ecological characteristics of endophytic fungi in this research,and further high-efficiency strains were screened and their fermentation conditions were optimized,providing a theoretical basis for better use of blueberry endophytic fungi,and the main results of this thesis are as follows:1.To reveal the diversity and ecological characteristics of blueberry endophytic fungi,the High-throughput sequencing technology was applied,and the results showed that a variety of fungi OTUs were found in wild blueberry roots,including putative Ericoid mycorrhizal（ERM）fungi,Ectomycorrhizas mycorrhizal（ECM）fungi and common dark septate endophytes（DSE）.The advantageous phylums were Ascomycota and Basidiomycota,and the main genus were Russula and Sebacina.Through the analysis,two fungal communities in wild blueberry roots showed different responses to different altitudes,similarly,geographical and environmental factors also influenced the community structure and diversity of blueberry endophytic fungi,wherein soil pH was the most important in environmental factors.In addition,most of the dominant fungus（Tags>1000）in the wild blueberry roots had a preference to the altitude and host to some extent.2.540 strains of slow growing strains were isolated by pure culture,and then through using morphological methods and molecular identification,68 strains of different strains were found,which belonged to 21 fungal taxa,including common ERM fungi（Oidiodendron sp.）,DSE（Phialocephala fortinii）and many non-identified species in Helotiales.Additionally,the strain 14-16 and 1-28 could be new species.3.The cultivation of mycorrhizal fungal community in wild blueberry roots was affected by the host,geographical and environmental factors.By comparing the results of high-throughput sequencing and pure culture separation,endophytic fungi can be cultured was fewer in habitat of high altitude than in that of low altitude.4.In an open ecological system in the Sebacinales,Helotiales group and DSE Phialocephala fortinii are the dominant groups of the ERM fungal community,and are frequently isolated Oidiodendron and Rhizoscyphus typical ERM fungi just pure culture advantage conditions.5.By inoculating 10 selected representative isolates in blueberry cultivars,the blueberry endophytic fungi strain 3-41（Cryptosporiopsis ericae strain 3-41）and 14-16（Oidiodendron sp.strain 14-16）had significant effects on promoting the aboveground biomass of blueberry,and the strain of 3-41 also significantly increased the underground biomass.6.The results in the experiment of optimizing solid fermentation condition of high-efficiency strain showed that the optimum solid fermentation condition of the strain3-41 was as follows:wheat bran 79%,corn flour 15%,soybean flour 6%,KH₂PO₄ 0.03%,MgSO₄·7H₂O 0.02%,initial moisture content 80%,temperature 24°C and pH 7;the strain14-32（Rhizoscyphus aff.ericae strain 14-32）was wheat bran 87%,corn flour 10%,soybean flour 3%,KH₂PO₄ 0.03%,MgSO₄·7H₂O 0.02%,initial moisture content 80%,temperature 24°C and pH 6;and the strain 14-16 was 76%wheat bran,corn flour 15%,soybean flour 9%,KH₂PO₄ 0.03%,MgSO₄·7H₂O 0.02%,initial water content 40%,temperature 28°C and pH 6.