The Impact of Cd Pollution on Arbuscular Mycorrhizal Fungal Communities in Paddy Fields

Arbuscular mycorrhizal fungi (AMF) demonstrate considerable potential for remediating soils contaminated with heavy metals. However, comprehensive research examining the effects of cadmium (Cd) contamination on AMF communities in paddy fields remains scarce, constraining their broader application in such environments. In this study, high-throughput sequencing was utilized to assess AMF community structure in paddy soils subjected to five distinct levels of Cd contamination. The study also explored the effect of different soil properties on AMF community dynamics. A total of 188 AMF taxa were identified across all soil samples, spanning four families. The Claroideoglomeraceae family emerged as the predominant group, exhibiting notable Cd tolerance. While elevated Cd concentrations inhibited the AMF community structure, lower concentrations increased the α-diversity of the community. Furthermore, soil-available phosphorus, calcium levels, and pH were found to be critical factors driving shifts in AMF community structure. Redundancy analysis explicitly quantified the relative strength of environmental factors, demonstrating that phosphorus and pH directly influenced the AMF community structure through significant effects, while Cd and calcium exerted their influence via indirect or nonlinear pathways. Given the relative abundance advantage of Claroideoglomeraceae in Cd-contaminated environments and its positive correlation with Cd concentration, we hypothesize that this group may exhibit Cd tolerance. Therefore, it could be considered a potential candidate species for prioritization in future field inoculation trials, and its practical application potential should be further validated.