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Archaeal rhizosphere communities differ between the native and invasive lineages of the wetland plant Phragmites australis (common reed) in a Chesapeake Bay subestuary

Yarwood, S. A., Baldwin, A. H., Gonzalez Mateu, M., Buyer, J. S.
Biological invasions 2016 v.18 no.9 pp. 2717-2728
Archaea, Phragmites australis, bacteria, biogeochemistry, community structure, ecological invasion, fatty acid composition, fungi, genes, indigenous species, invasive species, methane, methanogens, microbial biomass, microbial communities, oxidants, phospholipid fatty acids, restriction fragment length polymorphism, rhizosphere, ribosomal RNA, soil, wetland plants, wetlands, Chesapeake Bay, North America
Phragmites australis is a common wetland plant species worldwide and best known in North America as a persistent invasive species. Only in recent decades was a native lineage, Phragmites australis subsp. americanus, confirmed in North American wetlands. This study investigated whether the two lineages support unique microbial communities in the rhizosphere. Paired stands of the native and invasive lineages were sampled at four locations across a Chesapeake Bay subestuary to assess differences in soil chemical parameters and the microbial community. Microbial characterization included quantification of genes coding for bacterial and archaeal 16S rRNA, archaeal ammonia-monooxygenase, methane co-enzyme A, and particulate methane-monooxygenase. These gene targets helped quantify bacterial biomass, archaeal biomass, ammonia-oxidizers, methanogens, and methane oxidizers, respectively. Bacterial and archaeal community composition was determined by creating terminal restriction fragment length polymorphism profiles of the 16S rRNA, and bacterial and fungal composition was assessed using phospholipid fatty acid profiles. Bacterial biomass and composition did not differ between the two lineages, but significant differences were observed in archaeal community composition. There were significantly more copies of archaeal 16S rRNA genes in invasive (1.8 × 10⁸ g⁻¹ soil) compared to native (7.2 × 10⁷ g⁻¹ soil) lineages (P = 0.04) and composition profiles were significantly different according to PerMANOVA (P = 0.006). Phospholipid fatty acid profiles also differed between invasive and native lineages (P = 0.023). These findings support other studies that have noted the ability of native and invasive Phragmites to differentially affect soil biogeochemistry and suggest that archaea in the rhizosphere of wetland plants may be more sensitive to plant variation than bacteria.