Degradation of the wild fruit forest infulences the diversity of soil bacterial and fungal communities in the Tianshan Mountains

Abstract

Background and aims: The wild fruit forest in the Tianshan Mountains is a vital reservoir of germplasm resources for improving the genetic diversity of temperate fruit trees worldwide. In recent years, however, this forest ecosystem has been seriously threatened by outbreaks of diseases and insect pests as well as climate change. Analyses of soil microbial community diversity following degradation of the forest could provide insights into its impact on soil quality and the ecosystem. Methods In this study, we applied 16S rRNA and ITS gene sequencing to analyze the microbial community composition of soil samples surrounding healthy and degraded Malus sieversii and also recorded soil physiochemical variables. Results we found that degradation of the wild fruit forest due to M. sieversii decline significantly reduced the beta diversity of topsoil bacterial communities and fungal symbiotic groups. The decline in M. sieversii loosened connections among bacterial and fungal co-occurrence networks. Analysis of community assemblies revealed that migration rates of bacteria and fungi were both higher in the topsoil around degraded M. sieversii, thus suggesting that dispersal restriction affects microbial species in the degraded wild fruit forest. Narrow niche-breadth bacterial species were preferentially selected by the decline in M. sieversii, leading in turn to more variation in fungal functional diversity (i.e., increased beta diversity of pathogenetic fungi but decreased diversities of symbiotic and saprotrophic fungi). Conclusions Our results show that degradation of M. sieversii lead to variations in microbial diversity and in the underlying function of forest microorganisms. The study offers the inclusion of microbial information during soil quality monitoring is crucial to gain a better, more accurate understanding of how degradation of M. sieversii impacts soil quality and the ecosystem.