The microalgae-bacteria symbiotic inoculation

干旱地区的土地退化，表现为沙质土壤结构崩解和功能衰退，限制了可持续发展。虽然微生物接种剂提供了恢复途径，但单株应用通常受限于环境适应性较差。设计上功能互补的微藻-细菌共生群落，利用其代谢协同和生态位互补的核心优势，展现出超越单一菌株的土壤修复潜力。它在促进生物土壤地壳形成、增强土壤稳定性和强化生态功能方面尤为有效。 然而，该联盟通过调控本土微生物网络的结构和稳定性来推动生态系统功能恢复的根本机制尚不清楚。在这里，我们构建了一个微藻-细菌共生群落，并通过微观实验结合风洞试验、高通量测序和分子生态网络分析来测试其效果。该联盟产生了协同效应，使植物地面生物量增加了110%，并增强了生物地壳的形成。因此，临界阈值风速从5.5米提升至11.9米s⁻¹，土壤多功能性较对照组提升了205%。胞外聚合物质（EPS）与土壤骨团稳定性呈强正相关（R² ≥ 0.66）。关键是，接种增强了确定性环境过滤（例如，将蓝藻的均匀选择提升至39.8%），并塑造了一个更简洁、更稳定的微生物共出现网络。 结构方程建模指出，网络稳定性而非复杂性是推动土壤多功能性及最终生态系统抗性的核心枢纽。我们的研究展示了理性设计的微生物联盟在生态恢复中的潜力，并为可预测微生物组工程的机制提供了新见解。Land degradation in arid regions, manifested as the disintegration of sandy soil structure and functional decline, restricts sustainable development. While microbial inoculants offer restoration pathways, single-strain applications are often limited by poor environmental adaptability. A rationally designed microalgae-bacteria symbiotic consortium, leveraging its core advantages of metabolic synergy and niche complementarity, exhibits greater soil remediation potential than single strains. It is particularly effective in promoting biocrust formation, enhancing soil stability, and strengthening ecological functions. However, the fundamental mechanism by which this consortium drives ecosystem functional recovery via regulating the structure and stability of indigenous microbial networks remains unclear. Here, we constructed a microalgae-bacteria symbiotic consortium and tested its effects through microcosm experiments combined with wind tunnel experiments, high-throughput sequencing, and molecular ecological network analysis. This consortium generated synergistic effects, increasing plant aboveground biomass by 110% and enhancing biocrust formation. Accordingly, the critical threshold wind speed increased from 5.5 m s⁻¹ to 11.9 m s⁻¹, and soil multifunctionality improved by 205% compared to the control group. Extracellular polymeric substances (EPS) showed a strong positive correlation with soil aggregate stability (R² ≥ 0.66). Importantly, inoculation enhanced deterministic environmental filtering (e.g., increasing the homogeneous selection of cyanobacteria to 39.8%) and shaped a more compact and stable microbial co-occurrence network. Structural equation modeling (SEM) indicated that network stability, rather than complexity, is the core hub driving soil multifunctionality and ultimately ecosystem resistance. Our study demonstrates the potential of rationally designed microbial consortia in ecological restoration and provides new insights into the mechanisms underlying predictable microbiome engineering.