紫花针茅根际和体内真菌群落结构及与土壤环境因子的相关性研究

目的] 探究青藏高原不同地区高寒草原紫花针茅根际和体内真菌群落的组成、多样性等特征，及与土壤环境因子（理化性质和酶活性）间的相互关系。方法] 从青藏高原不同地区采集紫花针茅样品，应用土壤化学方法分析根际土壤理化性质和酶活性，并采用Illumina Miseq高通量测序技术，解析根际土壤和体内真菌群落组成和丰度、Alpha多样性和菌群结构，同时分析了紫花针茅根际真菌种群多样性与土壤环境因子的相关性，厘清了影响紫花针茅根际真菌区系的土壤环境因素。结果] 三个采样地的根际土壤呈中性偏碱，土壤理化性质和酶活性变化各异。高通量测序共得到314801条有效序列和4491个OTUs；XZ样地的紫花针茅真菌多样性和丰富度相对偏低，GS样地最高。在门分类水平上，子囊菌门Ascomycota和担子菌门Basidiomycota是主要内生真菌类群，占总菌群的88.28%。不同采样地区紫花针茅体内真菌群落结构存在明显差异，而根际土壤真菌群落结构差异不大。相关性分析表明，紫花针茅真菌多样性与土壤pH、有效钾、铁、钙、镁、多酚氧化酶、过氧化物酶和脱氢酶呈显著（P<0.05）或极显著（P<0.01）正相关，而与海拔、土壤酸性磷酸酶呈极显著负相关。RDA分析发现，紫花针茅根际土壤真菌不同，影响的土壤环境因子也不同。结论] 青藏高原高寒草地紫花针茅根际和体内栖息着丰富的真菌群落，其组成和多样性受多种土壤环境因子影响，且影响不同真菌群落的主要土壤环境因子也不同。本研究对于有益微生物资源的开发、利用及保护具有重要意义，并为紫花针茅草原保育和合理开发利用提供科学依据。

The structure of rhizosphere soil and endophytic fungal communities associated with Stipa purpurea and their correlation with soil environmental factors

Objective] The aim of this study is to explore the fungal community structures associated with rhizosphere soil, root and leaf of Stipa purpurea, and the relationship between rhizosphere soil fungal community structure and soil environmental factors. Methods] We collected soil and plant samples from three different sites which located in the Qinghai-Tibetan Plateau. Soil physiochemical properties and enzymatic activities were detected by using the methods of soil chemistry, and rhizospheric and endophytic fungal community structures were analysed by Illumina Miseq high throughput sequencing technology. Based on this, we resolved the composition and richness, Alpha diversity and the characteristics of fungal community structures. Meanwhile, we also analyzed the correlation between the diversity of rhizosphere fungi and the soil environmental factors, and clarified the soil environmental factors which effected the rhizosphere mycobiota structure of Stipa purpurea. Results] The results showed that rhizosphere soil pH were neutral or leaning alkalinity of three sampling sites, soil physiochemical properties and enzymatic activities changed differently in different sites. We obtained a total of 314801 effective sequences and 4611 OTUs by high throughput sequencing, the diversity and richness of fungal communities were the highest in GanSu site, and the lowest in XiZang site. The fungal communities'' dominant phyla of all samples were Ascomycota and Basidiomycota, accounting for 88.28% of the total. The endophytic fungal communities had significant variations in different sampling sites, while rhizosphere soil fungal communities had no obvious differences in three sites. Correlation analysis showed that the diversity of fungal community was significant positive correlated with soil pH, the contents of available K, Fe, Ca, Mg, and soil peroxidase, soil polyphenol oxidase, soil dehydrogenase, while significant negative correlated with altitude and soil acid phosphatase. Redundancy analysis indicated that different fungal communities corresponding different impact environmental factors. Conclusion] A wide variety of fungal communities are associated with the roots, leaves and rhizosphere soil of S. purpurea. The fungal assemblages are influenced by multiple soil environmental factors, and different fungal communities have different influencing factors. This study was significant to the exploitation of the beneficial microbial resource, and also providing a theoretical basis for the conservation and reasonable development these natural grasslands.