科尔沁沙地不同林龄樟子松人工林土壤真菌-细菌共现模式

Aims The interactions between soil fungal and bacterial communities are crucial for maintaining microhabitat balance. However, the key factors regulating their co-occurrence patterns remain poorly understood. The study aims to reveal the interactions between fungal and bacterial communities in Pinus sylvestris var. mongolica plantations in Horqin Desert. Soil samples were collected from plantations of different stand ages (half-mature, near-mature, and mature forest) with a reference sandy grassland as control. Methods Based on the 16S rRNA high-throughput sequencing technology, molecular ecological network analysis was conducted to investigate the characteristics and driving factors of soil fungal-bacterial networks in Pinus sylvestris var. mongolica plantations. Important findings The results revealed that: (1) as stand age increased, the complexity of soil fungal-bacterial network decreased. The half-mature forest exhibited the most intense fungal-bacterial interactions, with the highest stability and resistance to disturbance. In contrast, the sandy grassland displayed a more complex network overall. The synergistic relationships predominated among bacterial communities in both the plantation and sandy grassland, indicating a more intensive interaction within bacterial communities. (2) Key nodes of the soil fungal-bacterial network varied across different stand ages, with all identified key nodes being bacterial operational taxonomic units (OTUs). The half-mature forest exhibited the highest number of key nodes, with Proteobacteria representing the largest proportion. Acidobacteria were identified as key nodes in the co-occurrence networks of both the half-mature and near-mature forests. These results suggest that Proteobacteria and Acidobacteria play crucial roles in maintaining the stability of the fungal-bacterial network, while no key nodes were identified in the sandy grassland. (3) The complexity of soil fungal-bacterial network was primarily influenced by soil available phosphorus and water content, while the network’s stability was significantly correlated with soil organic matter and available phosphorus content. These findings enhance our understanding of the soil fungal-bacterial co-occurrence network and provide valuable insights for the sustainable management of P. sylvestris var. mongolica plantations.