Local environment drives rapid shifts in composition and phylogenetic clustering of seagrass microbiomes

Abstract

Plant microbiomes depend on environmental conditions, stochasticity, host species, and genotype identity. Eelgrass (Zostera marina) is a unique system for plant–microbe interactions as a marine angiosperm growing in a physiologically-challenging environment with anoxic sediment, periodic exposure to air at low tide, and fluctuations in water clarity and flow. We tested the influence of host origin versus environment on eelgrass microbiome composition by transplanting 768 plants among four sites within Bodega Harbor, CA. Over three months following transplantation, we sampled microbial communities monthly on leaves and roots and sequenced the V4–V5 region of the 16S rRNA gene to assess community composition. The main driver of leaf and root microbiome composition was destination site; more modest effects of host origin site did not last longer than one month. Community phylogenetic analyses suggested that environmental filtering structures these communities, but the strength and nature of this filtering varies among sites and over time and roots and leaves show opposing gradients in clustering along a temperature gradient. We demonstrate that local environmental differences create rapid shifts in associated microbial community composition with potential functional implications for rapid host acclimation under shifting environmental conditions.

Impact of persistently high sea surface temperatures on the rhizobiomes of Zostera marina in a Baltic Sea benthocosms

“…As discussed before, two different sulfate reducer taxa (Desulfocapsaceae and Desulfobacteraceae) were found as the most abundant in summer WR which highlights a possible stronger sulfate reduction in samples from this treatment compared to the other treatments. These results are consistent to the ones from Kardish and Stachowicz (2023). They suggest that members of Desulfocapsaceae (with conserved sulfur metabolism), found associated with Z. marina roots in a warmer environment, are adapted to warmer temperatures and could be good indicators of environmental changes.…”

Taxonomic and functional β-diversity patterns reveal stochastic assembly rules in microbial communities of seagrass beds

“…Assembly processes, which encompass deterministic and stochastic components, provide insights into variations in community structure composition and diversity dynamics ( Prosser et al., 2007 ). Currently, the latter has garnered significant attention and research focus in seagrass habitats ( Crump et al., 2018 ; Liu et al., 2022 ; Kardish and Stachowicz, 2023 ). However, investigations into community assembly, particularly concerning microbial communities, remain relatively limited ( Leibold et al., 2017 ; Zhou and Ning, 2017 ; Fahrig, 2019 ).…”