Effects of different fertilizers on bacterial-viral co-encoding of carbon cycle-related genes in paddy soil

Viruses play a crucial role in influencing bacterial survival and metabolism across various environments by encoding auxiliary metabolism genes , thereby impacting biogeochemical cycles. This study aims to investigate the abundance of carbon cycle-related functional genes jointly encoded by viruses and bacteria in long-term differently fertilized paddy soil, providing insights into viral-bacterial interactions and informing efficient fertilization and management strategies for paddy soils in the red soil region. Soil samples were collected from a long-term fertilization positioning experiment involving four treatments: control CK with no fertilizer input, chemical fertilizer application NPK, returning green manure Astragalus smicus application to early rice M1,and returning Astragalus smicus to early rice field and straw to late rice field M2. We employed Metagenomic and Virome sequencing technologies to analyze the structural composition of bacterial and viral communities, compared the distribution of viral and bacterial functional genes related to the carbon cycle based on the KEGG carbon metabolism pathway, and identified phage and bacterial species corresponding to shared carbon cycle genes from the sequencing data.ResultsThe bacterial community in paddy soil was predominantly composed of Proteobacteria, Acidobacteria and Chloroflexi , compared to CK, the abundance of Proteobacteria, Actinobacteria was increased and Chloroflexi, Actinobacteria was decreased in M2 treatment. The most abundant viral taxa included Microviridae,Circoviridae and Siphoviridae in the paddy soil, and the relative abundance of dominant populations of viral communities in CK was higher than that in the fertilization treatments. The relative abundance of Microviridae in M2 treatment was higher than that of other fertilization treatment.