Effects of fertilization on the bacterial diversity and functions of potato roots

Abstract:

[Background] Fertilization is a common agronomic measure, while there are few studies about the effects of fertilization on the bacterial diversity and functions of potato roots. [Objective] To study the effects of non-fertilization and conventional fertilization on the community composition, structure, and function of bacteria in potato root samples collected from Zhangjiakou. [Methods] The 16S rRNA gene sequencing was employed to analyze the root bacteria of potato under fertilization and non-fertilization treatments. [Results] Fertilization affected the bacterial abundance of potato plants at the seedling stage and tuber formation stage. At the seedling stage, fertilization significantly reduced the abundance of Planctomycota, Cyanobacteria, and Firmicutes in the rhizosphere and significantly increased the abundance of Bdellovibrionota, Armatimonadota, Bacteroidota, and Patescibacteria on the root surface and the abundance of Chloroflexi and Planctomycetota in the roots, compared with non-fertilization treatment. At the tuber formation stage, fertilization significantly increased the abundance of Acidobacteriota, Firmicutes, Actinobacteriota, Bacteroidota, and Patescibacteria in the rhizosphere, Armatimonadota, Bacteroidota, and Bdellovibrionota on the root surface, and Armatimonadota and Hydrogenedentes in the roots. Meanwhile, it significantly decreased the abundance of Cyanobacteria in the rhizosphere, Gemmatimonadota, Cyanobacteria, and Myxococcota on the root surface, and Nitrospirota and RCP2-54 in the roots. In addition, fertilization affected the gene abundance of potato plants at the seedling stage and tuber formation stage. At the seedling stage, compared with non-fertilization treatment, fertilization significantly increased the abundance of genes involved in the biosynthesis of other secondary metabolites, glycan biosynthesis and metabolism, and replication and repair on the root surface and those for replication and repair in the roots. At the tuber formation stage, fertilization significantly increased the abundance of the genes associated with the metabolism of terpenoids and polyketides and lipid metabolism in the rhizosphere, replication and repair in the roots, and the metabolism of terpenoids and polyketides and lipid metabolism on the root surface. Meanwhile, it significantly reduced the abundance of genes involved in the energy metabolism, metabolism of cofactors and vitamins, metabolism of other amino acids in the rhizosphere and those participating in transcription, folding, sorting, degradation, and energy metabolism on the root surface. [Conclusion] Conventional fertilization could improve the root microbial structure and gene function abundance. That is, compared with the control group, fertilization increases the bacterial richness and diversity and the abundance of genes associated with the metabolism and energy conversion and utilization, thereby improving the potato yield.