Cross-domain microbial interactions mediate soil multifunctionality during crop growth stages
Crop cultivation substantially alters soil microbial environments, while microorganisms regulate crop growth through nutrient cycling. However, the responses of cross-domain microbial interactions to crop growth stages and their roles in shaping soil multifunctionality remain poorly understood. Here, corn-planted plots were established with bare land as the control, and soil samples were collected from the topsoil (0-2 cm) and subsoil (15-20 cm) across four corn growth stages (seeding, heading, flowering, and post-harvest). This study aimed to elucidate the dynamic changes in microbial community structure and association patterns across crop growth stages and identify the mechanisms through which these phenomena regulate soil multifunctionality. Results demonstrated that variations in the diversity and abundance of bacteria and protists across soil depths and growth stages were driven by environmental variables. Moreover, microbial abundance was more sensitive to environmental factors than diversity, and protists were more responsive in terms of abundance and diversity than bacteria. Cross-domain network indicators exhibited clear spatial stratification and nonlinear temporal responses. Specifically, association patterns in the topsoil increased during growth and declined after harvest, whereas those in the subsoil remained low and decreased. Although network indicators exhibited similar temporal trends across both treatments, the indicators were higher in the corn treatment. Structural equation modeling revealed that although the microbial community structure was associated with changes in soil multifunctionality, association patterns better explained variations in soil multifunctionality. Overall, this study demonstrates that cross-domain microbial interactions are key drivers of soil multifunctionality, thereby offering theoretical insights into microbial regulatory mechanisms under crop growth conditions.