腾格里沙漠东南缘藓结皮植物–土壤连续体不同粒径土壤微生物群落多样性

Microbial community diversity among different soil particle sizes of mossy biocrusts–soil continuum in the southeastern Tengger Desert

藓结皮作为干旱半干旱地区生物土壤结皮发育演替的稳定阶段,参与了荒漠生态系统的物质循环和能量流动,为微生物多样性的维持提供了微生境。了解藓结皮植物–土壤连续体不同粒径土壤微生物群落多样性对认识藓结皮的生态过程具有重要意义。本研究采用Illumina MiSeq技术对藓结皮植物–土壤连续体以及结皮下层不同粒径土壤微生物多样性和群落结构进行了分析。测序结果得到10,730个细菌变异序列(ASVs)和3,035个真菌ASVs。藓结皮附着土细菌群落α多样性指数低于结皮下层,而藓结皮附着土真菌群落α多样性指数显著高于结皮下层和结皮抖落土。藓结皮层常见的细菌门有放线菌门、变形菌门、绿弯菌门、酸杆菌门、蓝细菌门、拟杆菌门,结皮下层土壤常见的细菌门有放线菌门、变形菌门、绿弯菌门、酸杆菌门,藓结皮附着土细菌群落变形菌门和拟杆菌门相对多度高于不同粒径藓结皮抖落土及藓结皮下层土。藓结皮层和藓结皮下层常见的真菌门有子囊菌门和担子菌门。藓结皮附着土与不同粒径抖落土在细菌群落微枝形杆菌属(Microvirga)、红色杆菌属(Rubrobacter)、苔藓杆菌属(Bryobacter)、土壤红杆菌属(Solirubrobacter)、地嗜皮菌属(Geodermatophilus)、鞘氨醇单胞菌属(Sphingomonas)、芽生球菌属(Blastococcus)、诺卡氏菌属(Nocardioides)、Rubellimicrobium、贫养杆菌属(Modestobacter)相对多度存在显著差异,藓结皮附着土与不同粒径抖落土在真菌群落曲霉属(Aspergillus)、Knufia、Darksidea、粉褶蕈属(Entoloma)、Monosporascus、Bhatiellae、亚隔孢壳属(Didymella)、链格孢属(Alternaria)、Cladosporium、镰刀菌属(Fusarium)相对多度上存在显著差异。藓结皮附着土细菌和真菌共现性网络比不同粒径藓结皮抖落土和藓结皮下层土细菌和真菌共现性网络更复杂且连通性更好。这些研究结果有助于在微环境尺度探究生物土壤结皮参与荒漠生态系统生物地球化学循环的微生物多样性的变化规律。

Aims:Moss biocrust formation means the stable crust development of soils in arid and semiarid regions;the participate in the material cycle and energy flow of desert ecosystems and provide a microhabitat for the maintenance of microbial diversity.The microbial diversity of soil with different particle sizes in moss biocrusts–soil continuum is of great significance for understanding the ecological process of moss biocrusts.Method:In this study,we used Illumina MiSeq techniques to analyze the microbial diversity and community structure of different soil particle sizes in moss biocrusts–soil continuum and biocrust sublayer.Results:A total of 10,730 bacterial amplicon sequence variant(ASVs)and 3,035 fungal ASVs were obtained by sequencing.Theαdiversity index of the bacterial community was lower in the moss biocrust adhesion soil than in the biocrust layer,while theαdiversity index of the fungal community was significantly higher in the moss biocrust adhesion soil than in different soil particle sizes in moss biocrust sifting soil and biocrust sublayer.The common bacterial phyla of the moss biocrusts were Actinobacteria,Proteobacteria,Chloroflexi,Acidobacteria,Cyanobacteria and Bacteroidetes,while the common bacterial phyla of the biocrust sublayer soil were Actinobacteria,Proteobacteria,Chloroflexi and Acidobacteria.The common fungal phyla of the moss biocrust and biocrust layers included Ascomycota and Basidiomycota.The relative abundance of Proteobacteria and Bacteroidota was higher in the moss biocrust adhesion soil than in moss biocrust sifting soil and biocrust sublayer.Significant differences of relative abundance in the bacterial communities of Microvirga,Rubrobacter,Bryobacter,Solirubrobacter,Geodermatophilus,Sphingomonas,Nocardioides,Rubellimicrobium,Blastococcus and Modestobacter occurred between the moss biocrust adhesion soil and the moss biocrust sifting soil with different particle sizes.There were significant differences of relative abundance in the fungal communities of Aspergillus,Knufia,Darksidea,Entoloma,Monosporascus,Bhatiellae,Didymella,Alternaria,Cladosporium and Fusarium between the moss biocrust adhesion soil and the moss biocrust sifting soil with different particle sizes.The results of the cooccurrence network showed that there was more complex connectivity in the rhizosphere of the mossy biocrusts than in the bulk soil and mossy biocrust sublayer.Conclusion:These results are helpful to explore the changing rule of microbial diversity of biological soil crust participating in biogeochemical cycle of desert ecosystem at microenvironment scale.