苹果叶内生菌对山田胶锈菌侵染的时间响应

[Objective]By exploring the differences in the community structure of endophytic bacteria and fungi in different stages of apple leaf infection by Gymnosporangium yamadae,this study offers valuable insights for the development and exploitation of plant endophytic resources,thereby contributing to enhanced strategies for managing apple rust,establishing a foundation for comprehending the role of host endophytes in the interaction between pathogens and hosts.[Method]This study scrutinizes alternations in endophytic microbial communities within apple leaves at nine different stages after infection with G.yamadae through MiSeq high-throughput sequencing of the bacterial 16S rRNA amplicons and fungal ITS rRNA amplicons,at the same time,the uninfected leaves in the corresponding time period are also treated and analyzed,additionally,employing the PICRUSt2 platform,this study provides preliminary insights into the functions of microbial communities at specific disease timepoints.[Result]During the occurrence and development of rust disease,in addition to the visible leaves forming faded spots,spermogonia,nectar,and aecia,the endophytic microbiome has also changed.Even in the early stage of the disease that cannot be recognized by the naked eye,the endophytic microbial community has undergone huge fluctuations.In the leaves of infected and uninfected rust,the composition and structure of high-abundance microorganisms are similar.For endophytic bacteria,Proteobacteria,Firmicutes,Actinobacteriota,Bacteroidota and Acidobacteriota accounts for a relatively high proportion.Ascomycota and Basidiomycota are the most abundant groups in the fungal community.Further diversity analysis shows that a discernible pattern characterized by an initial increase and subsequent decrease in the alpha diversity of microbial communities in infected leaves,as the number of ASVs increased,the uniformity of the community also increased.A microbial co-occurrence network analysis reveals that the complexity of the bacterial community in infected leaves diminished initially and then rebounded.In terms of functional prediction of microbial communities,we find during the spermogonial stage,endophytic bacteria particularly exhibited heightened activity in genetic information processing,metabolism,and environmental information processing pathways.Endophytic fungi also significantly enriched a large number of metabolic pathways during the spermogonial stage and aecial stage,exhibiting abnormally active life activities.[Conclusion]Our research provides compelling evidence that the pathogen invasion disrupts the microbial community's diversity,aggregation,and networks,significantly impacting their ecological functions.The aggregation of the host endophytic bacterial community is profoundly affected by rust disease,while the fungal community is mainly affected by the development stage.The changes of the community explaines the immune regulation of the host in the face of pathogen invasion and the pathogenicity of pathogenic fungi from a new perspective,enhancing our understanding of disease-induced alterations in the assembly,co-occurrence,and functionality of plant microbiomes.