Plant species within Streptanthoid Complex associate with distinct microbial communities that shift to be more similar under drought

• Published in: Ecology and evolution Vol. 14; no. 3; pp. e11174 - n/a
• Main Authors: Igwe, Alexandria N., Pearse, Ian S., Aguilar, Jessica M., Strauss, Sharon Y., Vannette, Rachel L.
• Format: Journal Article
• Language: English
• Published: England John Wiley & Sons, Inc 01.03.2024; John Wiley and Sons Inc; Wiley
• Subjects: Affinity; Bacteria; Biodiversity; Community structure; Drought; Drought resistance; Flowers & plants; Gene sequencing; Global Change Ecology; Gram-negative bacteria; Gram-positive bacteria; Microbial activity; Microbial Ecology; Microbiomes; Microbiomics; Microorganisms; Phylogeny; Plant species; Plants (botany); plant–microbe interaction; Precipitation; Rain; Relative abundance; Rhizoplane; rRNA 16S; Seeds; Serpentine; Serpentine soils; Soil environment; Soil structure; Soils; Species; Species diversity; Streptanthus; Water shortages; Water stress; United States > US; plant–microbe interaction; streptanthus; drought; serpentine; rhizoplane
• ISSN: 2045-7758; 2045-7758
• DOI: 10.1002/ece3.11174

Prolonged water stress can shift rhizoplane microbial communities, yet whether plant phylogenetic relatedness or drought tolerance predicts microbial responses is poorly understood. To explore this question, eight members of the Streptanthus clade with varying affinity to serpentine soil were subjected to three watering regimes. Rhizoplane bacterial communities were characterized using 16S rRNA gene amplicon sequencing and we compared the impact of watering treatment, soil affinity, and plant species identity on bacterial alpha and diversity. We determined which taxa were enriched among drought treatments using DESeq2 and identified features of soil affinity using random forest analysis. We show that water stress has a greater impact on microbial community structure than soil affinity or plant identity, even within a genus. Drought reduced alpha diversity overall, but plant species did not strongly differentiate alpha diversity. Watering altered the relative abundance of bacterial genera within Proteobacteria, Firmicutes, Bacteroidetes, Planctomycetes, and Acidobacteria, which responded similarly in the rhizoplane of most plant species. In addition, bacterial communities were more similar when plants received less water. Pseudarthrobacter was identified as a feature of affinity to serpentine soil while Bradyrhizobium, Chitinophaga, Rhodanobacter, and Paenibacillus were features associated with affinity to nonserpentine soils among Streptanthus. The homogenizing effect of drought on microbial communities and the increasing prevalence of Gram‐negative bacteria across all plant species suggest that effects of water stress on root‐associated microbiome structure may be predictable among closely related plant species that inhabit very different soil environments. The functional implications of observed changes in microbiome composition remain to be studied. Prolonged water stress has a significant impact on rhizoplane microbial communities in various plant species within the Streptanthus clade. This study found that the influence of water stress on microbial community structure is more pronounced than the effect of soil affinity or plant species identity. Drought reduced overall microbial diversity and led to similar changes in the relative abundance of certain bacterial genera across different plant species.