Abundance, diversity, and structure of Geobacteraceae community in paddy soil under long-term fertilization practices

Abstract

Geobacteraceae is an important dissimilatory Fe(III) reducer that affects the cycles of multiple elements. However, the way in which different long-term fertilization regimes influence the Geobacteraceae community in paddy soils remains unknown. Therefore, the objective of this study was to explore the responses of Geobacteraceae community in paddy soil to long-term chemical (nitrogen, phosphorus, and potassium) and/or organic (manure) fertilization practices. Illumina sequencing results showed that the species richness and diversity of Geobacteraceae community were not significantly changed by fertilizer treatments. Geobacteraceae in the treatments consisted of Geobacter (accounting for 90%–95% of total reads) and Geothermobacter genera (5%–10%), and all fertilizer treatments induced a significant (P < 0.05) decline in Geobacter and a marked enrichment of Geothermobacter. The taxonomic (based on Bray-Curtis distance) and phylogenetic structures (weighted-UniFrac distance) of the Geobacteraceae communities in all fertilizer treatments were clearly different from those in the non-fertilizer treatment; however, there were no significant changes among the different fertilization treatments. The variations in the Geobacteraceae community induced by long-term fertilization were mainly determined by changes in soil pH, total carbon, and total nitrogen. These findings provide an insight into the biogeochemistry of paddy soils and pave the way for harnessing the microbiome to improve soil fertility and environmental quality.