Soil chemical properties and geographical distance exerted effects on arbuscular mycorrhizal fungal community composition in pear orchards in Jiangsu Province, China

Abstract

Arbuscular mycorrhizal fungi (AMF) are considered to be natural biofertilizers because they provide the host with mineral nutrients, particularly phosphorus. However, there is insufficient information on AMF community compositions and their determining factors in pear orchard soils. In this study, hypotheses tested were that both soil characteristics and geographical distance influence the variation in AMF community composition. The community composition and diversity of AMF were examined using MiSeq sequencing in nine pear orchard soils in Jiangsu Province, China. Our data showed that a total of 108 operational taxonomic units (OTUs) were identified, with the majority belonging to Glomus (>90%). Nonmetric multidimensional scaling (NMDS) plots and PERMANOVA based on Bray-Curtis distance showed a clear separation of soil samples, suggesting significant dissimilarities in the AMF communities among the nine sampling sites. Distance-decay relationship (DDR) curves revealed that both geographical distance and soil chemical properties affect AMF community composition. Canonical correspondence analysis (CCA) and forward selection were used to examine the significance of environmental factors in more detail, and found that soil chemical properties and geographical distance correlated with AMF community composition. Particularly, pH, available phosphorus (AP) and Cu were the most significant soil properties that affected AMF communities. Partial CCA demonstrated that soil chemical properties exerted the primary influence on the assembly of the AMF communities in pear orchard soils, while geographical distance was less influential, which was supported by a partial Mantel analysis. Overall, we concluded that soil chemical properties and geographical distance were important parameters that affected AMF communities in Jiangsu Province, China, and the soils with moderate level of AP and low contents of heavy metals may preserve diverse AMF communities.