Assembly of root‐associated bacteria communities: interactions between abiotic and biotic factors

• Published in: Environmental Microbiology Reports
• Main Authors: Dean, Sarah L, Farrer, Emily C, Porras‐Alfaro, Andrea, Suding, Katharine N, Sinsabaugh, Robert L
• Other Authors: National Science Foundation
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 2014
• Subjects: Tundra
• Online Access: http://dx.doi.org/10.1111/1758-2229.12194; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2F1758-2229.12194; http://onlinelibrary.wiley.com/wol1/doi/10.1111/1758-2229.12194/fullpdf

Summary Nitrogen ( N ) deposition in many areas of the world is over an order of magnitude greater than it would be in absence of human activity. We ask how abiotic ( N ) and biotic (plant host and neighborhood) effects interact to influence root‐associated bacterial ( RAB ) community assembly. Using 454 pyrosequencing, we examined RAB communities from two dominant alpine tundra plants, G eum rossii and D eschampsia cespitosa , under control, N addition and D . cespitosa removal treatments, implemented in a factorial design. We hypothesized that host would have the strongest effect on RAB assembly, followed by N , then neighbor effects. The most dominant phyla were P roteobacteria (mostly G ammaproteobacteria ), A ctinobacteria , B acteroidetes and A cidobacteria . We found RAB communities were host specific, with only 17% overlap in operational taxonomic units. Host effects on composition were over twice as strong as N effects. D . cespitosa RAB diversity declined with N , while G . rossii RAB did not. D . cespitosa removal did not influence G . rossii RAB community composition, but G . rossii RAB diversity declined with N only when D . cespitosa was absent. We conclude that RAB of both hosts are sensitive to N enrichment, and RAB response to N is influenced by host identity and plant neighborhood.