甘肃省野生羊肚菌根际细菌群落与土壤环境因子相关性研究

Relationship between the bacterial community and environmental factors in the rhizosphere soil of wild morels in Gansu

摘要:

【背景】羊肚菌是全球广泛分布的物种，具有重要的经济和科研价值，其根际微生态系统各要素间的相关性研究相对较少。【目的】探究甘肃省不同地区野生羊肚菌根际土壤中细菌群 落-土壤理化性质及细菌群落-酶活性相关性。【方法】采用Illumina MiSeq高通量测序技术，对细菌群落组成进行测量，进而分析其多样性，最终揭示细菌群落-土壤理化性质及细菌群落-酶活性相互关系。【结果】根际土壤pH值随海拔升高而降低，然而土壤中大量元素含量、微量元素含量及酶活性随采样点呈现无规则变化。变形菌门(Proteobacteria)和放线菌门(Actinobacteria)在所有的采样点中都属于羊肚菌根际的优势细菌类群。LX采样点的细菌OTU数量和Shannon多样性指数均高于其他8个采样点。冗余分析(redundancy analysis，RDA)表明，变形菌门、拟杆菌门和疣微菌门与土壤含水量、养分和海拔呈正相关，与pH值、Ca、Mg含量呈负相关；放线菌门、酸杆菌门、扁平菌门与Mg含量、土壤脲酶和芳基硫酸酯酶呈正相关，与Fe、Se、速效钾含量、土壤脱氢酶和碱性磷酸酶呈负相关；芽单胞菌门和绿弯菌门与土壤pH值、Ca含量呈正相关；厚壁菌门与Fe、Se含量呈正相关。【结论】揭示了甘肃羊肚菌根际微生态系统各要素间的相互关系，为羊肚菌的高效种植提供了理论指导。

关键词:野生羊肚菌;根际土壤;环境因子;细菌群落;高通量测序

Abstract:

[Background] Morel (Morchella spp.), a worldwide species, has important scientific and economic value. However, there are few studies on the correlation among elements of its rhizosphere microecosystem. [Objective] We explored bacterial community-soil physico-chemical property and bacterial community-enzyme activity relationships in rhizosphere soil of wild morels in different areas of Gansu Province. [Methods] With Illumina MiSeq technology, the bacterial community structure in the rhizosphere soil was measured and then bacterial diversity was analyzed. On this basis, the above relationships were elucidated.[Results] The pH of rhizosphere soil decreased with the rise of elevation, but the major and minor elements and enzyme activity varied irregularly with sampling site. Proteobacteria and Actinobacteria dominated at all the sampling sites. The bacterial operational taxonomic units (OTUs) and Shannon's diversity index at LX were more higher than those at other sites. Redundancy analysis (RDA) showed that Proteobacteria, Bacteroidetes, and Verrucomicrobia were positively correlated with soil nutrients, soil water content, and elevation, but negatively correlated with soil pH and content of Ca and Mg. Actinobacteria, Acidobacteria, and Planctomycetes were in positive correlation with Mg content, soil urease, and arylsulfatase, but in negative correlation with the content of Fe, Se, and available potassium, soil dehydrogenase, and alkaline phosphatase. Gemmatimonadetes and Chloroflexi were positively correlated with soil pH and Ca content, whereas Firmicutes showed positive correlation with the content of Fe and Se. [Conclusion] We clarified the correlation among elements in the rhizosphere soil microecosystem of wild morels in Gansu, laying a theoretical foundation for efficient cultivation of morel.

Key words:wild morels;rhizosphere soil;environmental factors;bacterial community;high-throughput sequencing