板栗人工林根际土壤微生物及环境因子特征

Characteristics of soil microorganisms and environmental factors in the rhizosphere of Castanea mollissima plantation

为板栗人工林科学施肥和土壤改良提供理论依据,对广西东兰县、天峨县、林科院、隆安县以及平乐县的板栗人工林根际土壤微生物进行高通量测序及生物信息学分析,研究根际土壤微生物群落结构、多样性差异及与土壤环境因子之间的关系。结果表明:广西5个地区板栗人工林根际土壤环境因子、微生物群落结构与多样性存在较大的差异,整体而言,东兰县板栗人工林根际土壤环境质量表现最差。板栗人工林根际土壤微生物群落优势细菌在门分类水平上均以酸杆菌门和变形菌门为主(>50%),优势真菌均以担子菌门和子囊菌门为主(>95%),而优势菌属在不同地区差异较为明显。Pearson相关性和冗余分析表明,板栗人工林根际土壤微生物群落结构、丰富度和多样性与土壤环境因子有关。土壤脲酶活性与微生物群落Shannon、Chao1、ACE指数显著正相关(P<0.05)。同时土壤脲酶活性与细菌群落优势类群酸杆菌门、Rhizomicrobium及真菌群落优势类群担子菌门、子囊菌门、红菇属、圆孢牛肝菌属、丝盖伞属、锁瑚菌属的相对丰度显著相关(P<0.05)。土壤有效磷、速效钾含量与细菌群落ACE指数显著正相关(P<0.05),并且土壤速效钾含量也是影响板栗人工林根际土壤微生物群落结构变化的重要因子。土壤脲酶活性是影响广西板栗人工林根际土壤微生物群落结构、多样性和优势菌群相对丰度变化的关键驱动因子。

This study aimed to provide a theoretical basis for the scientific fertilization and soil improvement of Castanea mollissima plantation.High-throughput sequencing and bioinformatic analysis were employed in the rhizosphere soil microorganisms of Castanea mollissima plantations in Donglan County,Tiane County,the Institute of Forestry,Long’an County,and Pingle County in Guangxi,to determine soil bacterial and fungal community structures,diversity,and relationships with soil environmental factors.The results showed that the soil environmental factors,microbial community structures,and diversity differ in different regions in Guangxi.Overall,the worst soil environmental quality performance was observed in the Donglan County Castanea mollissima plantation.The dominant bacterial phyla across the regions included Acidobacteriota and Proteobacteria with more than 50%of the relative abundance of the bacteria,whereas the dominant fungal phyla were Basidiomycota and Ascomycota which made up over 95%of the relative fungal abundance,and the dominant microbial genera varied significantly in different Castanea mollissima plantations.Pearson and redundancy analysis correlation analysis indicated that soil microbial community structure,species richness,and diversity were associated with soil environmental factors,whereas soil urease activity as the primary factor significantly and positively affected the microbial community Shannon,Chao1 and ACE indices(P<0.05).Meanwhile,soil urease activity showed a significant correlation with the relative abundance of the dominant groups of the bacterial communities including Acidobacteria and Rhizomicrobium,and the dominant groups of the fungal communities including Basidiomycota,Ascomycota,Russula,Gyroporus,Inocybe and Clavulina(P<0.05).In addition,soil available phosphorus and potassium content were significantly and positively correlated with the bacterial community ACE index(P<0.05).Soil available potassium content was also an important factor affecting the change of microbial community structure in the rhizosphere soil of Castanea mollissima.In summary,soil urease activity was a key driver influencing the changes in microbial community structure,diversity and relative abundance of dominant microflora in the rhizosphere soil of Castanea mollissima in Guangxi.