Research on the effect of straw returning on soil virus-bacteria interaction mediating soil nitrogen cycling in paddy field

Soil viruses in paddy fields play a key but underunderstood role in farmland soil ecosystems, and play a non-negligible role in regulating host communities and elemental biogeochemical cycles. Studying the interaction mechanism between soil viruses and hosts and the expression of auxiliary metabolic genes (AMGs) in paddy fields under straw returning is helpful to reveal the far-reaching effects of viruses on soil nitrogen cycling in paddy fields, and provides a new perspective for understanding the role of soil viruses in the process of soil element biogeochemical cycling.Based on the long-term straw returning positioning experiment, this study set up five treatments: no straw returning (CK), 1.1 times the amount of straw returning (S1), 1.2 times the amount of straw returning (S2), 1.3 times the amount of straw returning (S3) and total straw returning (S), and the community composition of soil viruses and bacteria, the interaction between viruses and bacteria, and the role of AMGs in the nitrogen cycle process were analyzed by metagenomic and metavirome sequencing technology.Straw return enhances the interaction between paddy soil viruses and bacteria, enabling the expression of more AMGs, which play a significant role in the soil nitrogen cycle. The Peduoviridae interacts with the Acinetobacter to encode the gene ncd2/npd, facilitating the conversion of nitriles into nitrite, which is then further transformed into ammonium and nitrate nitrogen, thereby enhancing the availability of nitrogen in the soil during the rice tillering stage.