不同分布区胀果甘草原生境土壤微生物群落结构特征及其影响因素

胀果甘草（Glycyrrhiza inflata）主要分布于新疆、甘肃的荒漠区，是耐盐性最强的药用甘草，在改良盐碱地土壤中发挥着重要作用，其原生境土壤微生物群落结构特征是揭示种群分布影响因素及盐碱地修复机制的重要依据。从胀果甘草5个主产区采集原生境土壤，测定土壤理化指标，并采用高通量测序技术，结合Spearman、dbRDA等方法开展微生物群落组成及多样性特征研究，揭示不同分布区的优势微生物群落特征和影响因子。结果表明：真菌群落中曲霉属（Aspergillus）、地丝霉属（Geomyces）、镰刀菌属（Fusarium）和细菌群落中的寡养单胞菌属（Stenotrophomonas）、Marinimicrobium、Idiomarina是野生胀果甘草原生境土壤中的优势微生物类群。不同分布区的土壤真菌多样性和丰富度具有显著差异，但土壤细菌多样性和丰富度差异不显著；部分分布区土壤中的真菌和细菌种类差异较大。土壤理化因子中，土壤含水量和总含盐量对真菌和细菌的群落分布、丰富度有显著影响。原生境含水量与曲霉属（Aspergillus）、镰刀菌属（Fusarium）、链格孢属（Alternaria）、青霉属（Penicillium）真菌呈显著负相关；与Marinnimicrobium，Idiomarina、Aliifodinibius和需盐杆菌属（Salegentibacter）细菌呈显著正相关，与链霉菌属（Streptomyces）细菌呈显著负相关。原生境土壤总含盐量，与曲霉属（Aspergillus）、裸子囊菌属（Gymnoascus）、Aporospora真菌呈显著正相关，与镰刀菌属（Fusarium）、丝盖伞属（Inocybe）、硬皮马勃属（Scleroderma）真菌呈显著负相关；总盐含量与Marinimicrobium、Idiomarina、嗜盐单胞菌属（Halomonas）、Aliifodinibius、Salinimicrobium、需盐杆菌属（Salegentibacter）这6种细菌的丰富度存在显著正相关关系，与链霉菌属（Streptomyces）和鞘氨醇单胞菌属（Sphingomonas）细菌呈显著负相关。另外，土壤真菌和细菌的空间分布的异质性也与野生胀果甘草的生境类型和地理环境有关。原生境中丰富度高的嗜盐细菌可能与胀果甘草的盐适应和耐盐机制有密切关系。研究结果为野生胀果甘草的种群恢复、盐碱弃耕地的土壤功能修复研究提供理论依据。

Soil microbial community structure and its influencing factors in original habitat of Glycyrrhiza inflata in different distribution areas

Glycyrrhiza inflata is mainly distributed in the desert areas of Xinjiang and Gansu. It is the most salt tolerant medicinal Glycyrrhiza, and plays an important role in improving saline alkali soil. The soil microbial community structure of original habitat is an important basis to reveal the influencing factors of population distribution and the restoration mechanism of saline alkali soil of Glycyrrhiza inflata. In this study, the original habitat soil was collected from five main production areas of Glycyrrhiza inflata, the soil physical and chemical indexes were measured, and the microbial community composition and diversity characteristics were studied by high-throughput sequencing technology combined with Spearman, dbRDA and other methods, so as to reveal the characteristics and influencing factors of dominant microbial communities in different distribution areas. The results showed that Aspergillus, Geomyces, Fusarium in the fungal community, and Stenotrophomonas, Marinimicrobium, and Idiomarina in the bacterial community were the dominant soil microbial groups of the wild Glycyrrhiza inflata habitat. There were significant differences in soil fungal diversity and richness in different distribution areas, but there was no significant difference in soil bacterial diversity and richness. The species of fungi and bacteria in some distribution areas were quite different. Among the soil physical and chemical factors, soil water content and total salinity had significant effects on the community distribution and richness of fungi and bacteria. In original habitat water content was significantly negatively correlated with Aspergillus, Fusarium, Alternaria, Penicillium; significantly positively correlated with Marinnimicrobium, Idiomarina, Aliifodinibius and Salegentibacter, and significantly negatively correlated with Streptomyces. In original habitat soil total salt content was significantly positively correlated with Aspergillus, Gymnoascus, Aporospora, and significantly negatively correlated with Fusarium, Inocybe, Scleroderma; total salt content was significantly correlated with six species of Marinimicrobium, Idiomarina, Halomonas, Aliifodinibius, Salinimicrobium, and Salegentibacter. There was a significant positive correlation between bacterial abundance and a significant negative correlation with Streptomyces and Sphingomonas. In addition, the heterogeneity of the spatial distribution of soil fungi and bacteria was also related to the habitat type and geographical environment of wild Glycyrrhiza inflata. Halomonas, Aliifodinibius and Salegentibacter in this study are all halophilic bacteria in the habitat of Glycyrrhiza inflata. The high abundance of halophilic bacteria in the original habitat may be closely related to the salt adaptation and salt tolerance mechanism of Glycyrrhiza inflata. The results provide a theoretical basis for the population restoration of wild Glycyrrhiza inflata and the soil function restoration of saline alkali abandoned farmland.