The intensive cultivation of perennially grown Fritillaria pallidiflora Schrenk increases the complexity of bacterial-fungal cross-domain networks but reduces the evaluation of soil quality and ecological sustainability

Understanding how intensive continuous cultivation of perennial plants affects soil biological network complexity and community composition, as well as their relationship with soil quality and processes, is critical for sustainable agriculture development. However, our knowledge in this area remains limited. Here, we investigated the response of soil bacterial-fungal cross-domain networks to continuous cultivation by comparing the rhizosphere microbiome and functions of intensively cultivated Fritillaria pallidiflora Schrenk for 4 consecutive years (2, 3, and 4 years of continuous cultivation) with native ecosystems. Results showed that, unlike annual plant cultivation processes, intensive continuous cultivation increased the complexity of bacterial-fungal cross-domain networks, but reduced soil quality by 48.6 % and ecological sustainability by 77.3 % compared to the native environment. Fungi were found to dominate the microbial networks and tended to adapt to continuous cropping stress and control cross-domain networks through metabolic and ecological functions related to resource acquisition and competitive interactions, while bacteria tended to self-regulate, thereby influencing soil quality. Continuous cropping also led to strong bacterial and fungal impacts on soil nitrogen and sulfur cycling processes. Structural equation modeling revealed a reversal from positive feedback between microbial function and network complexity in native environments to negative feedback in continuous cropping systems. Therefore, our results suggest that intensive continuous cultivation of perennial plants drives changes in microbial community metabolism and interaction patterns that mediate increased complexity of soil bacterial-fungal cross-domain networks, resulting in severe negative impacts on soil quality and ecological sustainability.