Differential Effects of Wilt Disease on Arbuscular Mycorrhiza Fungi Communities in Roots and Rhizosphere Soil of Ammopiptanthus mongolicus

Ammopiptanthus mongolicus is a rare tertiary relic evergreen broad-leaved shrub that is seriously threatened by Fusarium wilt disease caused by Fusarium verticillioides. Mycorrhiza is a widely occurring symbiotic association of plant roots with arbuscular mycorrhizal fungi. To explore the relationship between wilt disease in A. mongolicus and arbuscular mycorrhiza, fungal communities in the roots and rhizosphere of healthy and diseased plants were analyzed using high-throughput sequencing technology based on specific primer amplicons. Arbuscular mycorrhizal fungal communities in roots were more strongly affected by Fusarium wilt disease than those in the rhizosphere. Wilt disease had no effect on α-diversity indices (Shannon and Simpson) in both the roots and rhizosphere soil, or on the phylogenetic diversity index (Pd) and richness indices (Chao, Ace and Sobs) in rhizosphere soil. However, it had a significant effect on the phylogenetic diversity index (Pd) and richness indices (Chao and Sobs) of arbuscular mycorrhizal fungal communities in the roots. Wilt disease increased the abundance of the genus Sclerocystis and decreased the abundance of Glomus. Arbuscular mycorrhizal fungal communities in diseased plants showed greater co-occurrence network complexity in both rhizosphere soil and roots. In terms of the ecological processes driving arbuscular mycorrhizal fungal community assembly, drift was intensified by wilt disease in both rhizosphere soil and roots. This study revealed the effect of wilt disease on arbuscular mycorrhizal fungal communities in the rhizosphere soil and roots of A. mongolicus. These findings provide important theoretical support and core AMF resources for the ecological prevention and control of A. mongolicus wilt disease.