民勤绿洲退耕地土壤微生物群落结构与功能多样性特征

为明确退耕阶段对土壤微生物群落结构和功能的影响，选取3个不同退耕阶段的荒漠绿洲区土壤为研究对象，通过宏基因组测序技术来研究不同阶段退耕地中土壤微生物群落的结构和功能多样性特征.结果表明，3个阶段退耕地土壤中放线菌门（Actinobacteria）、变形菌门（Proteobacteria）和芽单胞菌门（Gemmatimonadetes）的相对丰度存在显著差异，为优势菌门.与退耕前期相比，退耕修复后期增加了群体感应、卟啉与叶绿素代谢、泛酸盐和辅酶A生物合成以及苯乙烯降解的功能基因比例，且相对丰度存在显著差异（P<0.05），表明不同退耕阶段改变了土壤微生物群落营养循环与能量代谢的功能潜力.RDA结果表明电导率（EC）、速效钾（AK）和全氮（TN）对土壤微生物功能组成具有显著影响，其中EC对微生物功能组成的影响最大.不同退耕阶段对土壤微生物群落结构和功能组成多样性具有显著影响，在民勤绿洲退耕地生态修复中，微生物群落结构和功能组成对不同阶段的土壤修复敏感性可综合相关指标进行考虑.

Soil Microbial Community Structure and Functional Diversity Character of Abandoned Farmland in Minqin Oasis

To clarify the impact of the structure and function of soil microbial communities in the stage of abandoned farmland, three different stages of land abandoned in desert oasis areas were selected as the research objects. We used metagenomic sequencing technology to research soil microbial community structure and functional diversity characteristics of different stages of abandoned farmland. The results showed that there were significant differences in the relative abundance of the dominant phyla Actinobacteria, Proteobacteria, and Gemmatimonadetes in the soil of the three stages of returning farmland. Compared with that in the early stage of abandoned farmland, the later stage of abandoned farmland restoration increased the gene proportion involved in Quorum sensing, porphyrin and chlorophyll metabolism, pantothenate and CoA biosynthesis, and styrene degradation, and there was a significant difference in relative abundance (P<0.05), which indicated that different stages of abandoned farmland had changed the functional potential of the nutrient cycle and energy metabolism in soil microbial communities. The RDA results showed that EC, AK, and TN had a significant impact on the functional composition of soil microbes, and soil EC had the greatest impact on microbial functional composition. The results showed that different stages of abandoned farmland had a significant impact on the soil microbial community structure and functional composition. In the ecological restoration of abandoned farmland in Minqin Oasis, the sensitivity of microbial community structure and functional composition to soil restoration at different stages should be considered using comprehensive relevant indicators.