Rhizosphere bacterial and fungal communities during the growth of seedlings cultivated in an Alpine uncultivated meadow soil.

Background: seedlings are grown in alpine uncultivated meadow soil with rainfed agroecosystems to ensure the quality of after seedling transplantation. The aim was to investigate the rhizosphere bacterial and fungal communities during the growth stages of seedlings.

Methods: The bacterial and fungal communities were investigated by HiSeq sequencing of 16S and 18S rDNA, respectively.

Results: Proteobacteria and Bacteroidetes were bacterial dominant phyla throughout growth stages. Fungal dominant phyla varied with growth stages, dominant phyla Ascomycota and Chytridiomycota in AM5, dominant phyla Basidiomycota, Ascomycota and Zygomycota in BM5, and dominant phyla Basidiomycota and Ascomycota in CM5. There was no significant variation in the alpha-diversity of the bacterial and fungal communities, but significant variation was in the beta-diversity. We found that the variation of microbial community composition was accompanied by the changes in community function. The relative abundance of fungal pathogens increased with plant growth. We also identified the core microbes, significant-changing microbes, stage-specific microbes, and host-specific microbes. Plant weight, root length, root diameter, soil pH, rainfall, and climate temperature were the key divers to microbial community composition.

Conclusions: Our findings reported the variation and environmental drivers of rhizosphere bacterial and fungal communities during the growth of seedlings, which enhance the understanding of the rhizosphere microbial community in this habitat.