Variation of Arbuscular Mycorrhizal Fungi Communities Between Root and Rhizosphere Soil of Endangered Plant Heptacodium miconioides Along Elevation Gradient

Arbuscular mycorrhizal fungi (AMF) are considered crucial for the survival of many endangered plant species. However, the dynamics of AMF communities in the roots and rhizosphere soil of <i>Heptacodium miconioides</i>, particularly along elevation gradients, remain underexplored. This study investigates AMF colonization, spore density, and community structure in the root and rhizosphere soil of <i>H. miconioides</i> across an elevation range from 306 to 1028 m a.s.l., employing high-throughput sequencing. Our results show that AMF colonization and spore density in <i>H. miconioides</i> increased with elevation. <i>Glomus</i> was the dominant genus in both root and rhizosphere samples. Elevation significantly influenced the AMF community structure and diversity in the root, with alpha diversity decreasing linearly with elevation. In contrast, no significant elevation-related changes were observed in the rhizosphere soil alpha diversity. The difference in AMF beta diversity between the root and rhizosphere soil was lowest at the highest elevation. Compared to the rhizosphere soil, the degree and degree centralization of AMF community co-occurrence networks in the root showed a significant increase at higher elevations. Variations in soil properties, particularly soil pH, available phosphorus, and total nitrogen levels strongly influenced AMF communities in rhizosphere soil, while nitrate nitrogen, available potassium, and acid phosphatase were correlated with AMF communities in the root. These findings highlight the impact of elevation on AMF communities in both root and rhizosphere soil, providing valuable insights for the habitat restoration and conservation efforts for this species.