The study investigates the impact of drought on soil microbial communities and their co-occurrence networks in grassland mesocosms. Key findings include: 1. **Stability of Networks**: Drought promotes destabilizing properties in soil bacterial networks but not in fungal networks. Bacterial networks show higher connectivity, centrality, and lower modularity compared to fungal networks, indicating less stability under disturbance. 2. **Community Response**: Drought significantly affects both bacterial and fungal communities, with bacterial communities experiencing more pronounced changes. Bacterial richness and evenness decrease during drought, while fungal richness and evenness increase and recover quickly after rewetting. 3. **Network Properties**: Bacterial networks have stronger correlations between OTUs, more negative correlations, and are more connected and less modular than fungal networks. Bacterial networks are more resilient to drought, with abundant indicator OTUs being highly central and connected. 4. **Plant Community Impact**: Drought-induced shifts in plant community composition, particularly the dominance of fast-growing grass species, have long-lasting effects on bacterial networks and communities. These changes influence the recovery of microbial networks and communities, with bacterial networks showing stronger links to ecosystem functions such as CO2 and N2O fluxes. 5. **Ecosystem Functioning**: Bacterial communities predict the abundance of denitrification and N2O reduction genes, and these genes are significantly increased after rewetting. However, once soil moisture returns to control levels, N2O production returns to baseline levels. 6. **Legacy Effects**: Changes in soil microbial communities resulting from drought can have long-lasting effects on plant community composition, potentially reinforcing the dominance of certain species and altering future plant community dynamics. These findings highlight the importance of understanding how complex soil microbial communities respond to climate extremes and the potential for long-term consequences on ecosystem functioning.The study investigates the impact of drought on soil microbial communities and their co-occurrence networks in grassland mesocosms. Key findings include: 1. **Stability of Networks**: Drought promotes destabilizing properties in soil bacterial networks but not in fungal networks. Bacterial networks show higher connectivity, centrality, and lower modularity compared to fungal networks, indicating less stability under disturbance. 2. **Community Response**: Drought significantly affects both bacterial and fungal communities, with bacterial communities experiencing more pronounced changes. Bacterial richness and evenness decrease during drought, while fungal richness and evenness increase and recover quickly after rewetting. 3. **Network Properties**: Bacterial networks have stronger correlations between OTUs, more negative correlations, and are more connected and less modular than fungal networks. Bacterial networks are more resilient to drought, with abundant indicator OTUs being highly central and connected. 4. **Plant Community Impact**: Drought-induced shifts in plant community composition, particularly the dominance of fast-growing grass species, have long-lasting effects on bacterial networks and communities. These changes influence the recovery of microbial networks and communities, with bacterial networks showing stronger links to ecosystem functions such as CO2 and N2O fluxes. 5. **Ecosystem Functioning**: Bacterial communities predict the abundance of denitrification and N2O reduction genes, and these genes are significantly increased after rewetting. However, once soil moisture returns to control levels, N2O production returns to baseline levels. 6. **Legacy Effects**: Changes in soil microbial communities resulting from drought can have long-lasting effects on plant community composition, potentially reinforcing the dominance of certain species and altering future plant community dynamics. These findings highlight the importance of understanding how complex soil microbial communities respond to climate extremes and the potential for long-term consequences on ecosystem functioning.