为研究设施生态系统丛枝菌根(Arbuscular mycorrhiza，AM)真菌群落变化的关键驱动过程，采集设施番茄不同生长季(休耕、花期、果期)土壤样品，利用Illumina MiSeq高通量测序技术分析AM真菌物种和谱系多样性及群落结构变化特征，并结合群落谱系分析方法探讨不同生长季随机性过程和确定性过程之间的相对贡献。结果表明，不同生长季 AM 真菌的物种多样性和谱系多样性均发生显著改变:相比于休耕期，番茄生育期(花期、果期)土壤中AM真菌丰富度、Shannon多样性、Pielou均匀度、谱系多样性(PD)和平均成对谱系距离(MPD)分别显著下降了42。82%～59。18%、43。25%～48。31%、17。46%～25。40%、57。14%～67。86%和50。00%;除球囊霉属相对多度显著增加，近明球囊霉属和类球囊霉属相对多度均显著下降，原囊霉属相对多度先增加后降低。置换多元方差分析(PERMANOVA)和非度量多维度分析(NMDS)结果表明休耕期基于物种组成和谱系组成的 AM 真菌群落结构显著差别于番茄生育期，但花期和果期之间差异不显著。谱系分析结果显示，休耕期净亲缘关系指数NRI = 0，表明AM真菌在谱系结构上是随机的，花期和果期NRI>0，表明谱系聚集，暗示了AM真菌群落构建由随机性过程主导向确定性过程主导的转变，中性群落模型(NCM)结果也支持该推断。Mantel检验结果显示，土壤 pH、养分(有机碳、全量氮磷钾和有效磷)、盐分含量以及土壤温湿度作为确定性因素显著影响 AM 真菌群落的季相变化。综上所述，设施生态系统高集约化生产方式促进了 AM 真菌群落构建从随机性过程主导向确定性过程主导转变，导致多样性降低和群落结构变化，研究结果对揭示设施蔬菜栽培条件引起的土壤质量退化及其过程中的微生物组演变规律具有重要意义。
Variations in the Diversity and Community Assembly of Arbuscular Mycorrhizal Fungi in Greenhouse Soils During the Growing Season
[Objective]This study aimed to understand the key processes that drive the changes in diversity and community assembly of arbuscular mycorrhizal(AM)fungi in greenhouse ecosystem.[Method]Soil samples were collected during different growth stages(i.e.,fallow period,flowering stage,fruiting stage)of tomatoes in a greenhouse.Illumina MiSeq high-throughput pyrosequencing was performed to investigate the changes in taxonomic and phylogenetic diversity and community structure of AM fungi.The relative importance of stochastic and deterministic processes in structuring AM fungal community at different growth stages was analyzed by phylogenetic structure analysis.[Result]Results showed that both taxonomic and phylogenetic diversity of AM fungi varied significantly across different growth stages.Compared with the fallow period,OTU richness,Shannon diversity,Pielou evenness,phylogenetic diversity(PD)and mean pairwise phylogenetic distance(MPD)of AM fungi significantly decreased by 42.82%—59.18%、43.25%—48.31%、17.46%—25.40%、57.14%—67.86%and 50.00%,respectively,during the flowering and fruiting stages.In addition,the relative abundance of Glomus was promoted in the growing period,whereas the relative abundance of Claroideoglomus and Paraglomus decreased.Also the relative abundance of Archaeospora followed a unimodal pattern.Results of permutational multivariate analysis of variance(PERMANOVA)and non-metric multidimensional scaling analysis(NMDS)showed that,based on both taxonomic and phylogenetic data,the community structure of AM fungi in tomato soils during the fallow period was significantly different from that of the growing period,while the difference in community composition between the flowering and fruiting stage was not significant.According to the phylogenetic structure analysis,we found that the mean net relatedness index(NRI)across all samples was equal to zero at the fallow period,indicating phylogenetic random of AM fungal community,whereas the mean NRI was significantly greater than zero in both the flowering and the fruiting stages,indicating phylogenetic clustered.These results suggest that the primary ecological process structuring communities shifted from a stochastic process at early succession to a deterministic process at the tomato growing stage when local environmental filtering increased,which inference was also supported by the neutral community model(NCM)results.Mantel test showed that soil pH,soil nutrients(SOC,total NPK,and Olsen-P)and salt content,as well as soil temperature and humidity,significantly affected the seasonal changes of AM fungal community.[Conclusion]The highly intensive production stress in the greenhouse vegetable ecosystem promoted the transformation of the primary ecological process of AM fungal community assembly from a random process to a deterministic process,leading to a decrease in diversity and a change in community structure.Our results reveal the degradation of soil quality and the evolution of the microbiome in the process of greenhouse vegetable cultivation.
万方数据
维普
