天然高寒草地转变为混播人工草地对土壤微生物群落特征的影响

为了研究天然高寒草地转变为混播人工草地对土壤微生物群落的影响，采用高通量测序技术分析了青海省共和县的天然以及由天然转变为混播人工草地样地土壤中的微生物群落.结果表明，天然草地转变为混播人工草地后植被物种多样性和土壤有机质含量显著下降(P<0.05).在两块样地共检测到29个细菌门和11个真菌门的微生物.天然草地转变为人工草地后，土壤细菌的多样性显著升高，细菌的香农指数从9.51增加到9.89;土壤真菌的多样性降低但差异不显著.与天然草地相比，人工草地的土壤细菌与真菌群落结构、组成均发生了明显的变化，细菌群落结构与总有机质的含量、总氮含量和土壤含水量显著相关，真菌群落结构与总有机质含量和土壤含水量显著相关.线性判别分析(LEfSe)结果表明，暗黑菌门细菌(Atribacteria)和子囊菌门真菌(Ascomycota)可作为天然草地的指示微生物类群，出芽菌属细菌(Gemmata)和发菌科真菌(Trichocomaceae)可作为人工草地的指示微生物类群.利用Tax4Fun2对细菌群落功能的预测发现，天然草地向人工草地的转变影响了细菌群落对不同碳源的利用潜力.

Effects of the Transformation from Natural Alpine Grassland to Mixed Artificial Grassland on the Characteristics of Soil Microbial Community

This study aimed to analyze the effects of the transformation from natural alpine grassland (NAG) to mixed artificial grassland (MAG) on the characteristics of soil microbial community. We used Illumina Miseq high-throughput sequencing technology to investigate the soil microbial community of natural grassland and mixed artificial grassland. The results showed that plant diversity and the content of soil organic matter decreased significantly from NAG to MAG. In total, 29 and 11 phyla bacteria and fungi were detected, respectively. Compared with that in NAG, the Shannon indexes of the bacterial community increased significantly in MAG (from 9.51 to 9.89), whereas these differences were not significant between the NAG and MAG fungal community. The structure and composition of the soil microbial community showed significant differences between NAG and MAG. In addition, Mantel test results suggested that soil total organic matter, total nitrogen, and soil moisture were significantly correlated with variations in the bacterial community, and soil total organic matter and soil moisture were significantly correlated with variations in fungal community. The results of linear discriminant analysis (LEfSe) indicated that Atribacteria and Ascomycota microorganisms could be considered as the indicator groups for NAG, whereas Gemmata and Trichocomaceae microorganisms could be considered as the indicator groups for MAG. Tax4Fun2 results showed that the transition from NAG to MAG affected the utilization of different carbon sources by bacteria.