Soil Microsite Outweighs Cultivar Genotype Contribution to Brassica Rhizobacterial Community Structure

Type Article
Date 2021-04
Language English
Author(s) Klasek Scott A.1, 2, Brock Marcus T.2, Morrison Hilary G.1, Weinig Cynthia2, 3, 4, Maignien Lois1, 5
Affiliation(s) 1 : Josephine Bay Paul Ctr Comparat Mol Biol & Evolut, Marine Biol Lab, Woods Hole, MA 02543 USA.
2 : Univ Wyoming, Dept Bot, Laramie, WY 82071 USA.
3 : Univ Wyoming, Program Ecol, Laramie, WY 82071 USA.
4 : Univ Wyoming, Dept Mol Biol, Laramie, WY 82071 USA.
5 : Univ Bretagne Occidentale, Inst Europeen Mer, Lab Microbiol Extreme Environm, UMR 6197, Brest, France.
Source Frontiers In Microbiology (1664-302X) (Frontiers Media Sa), 2021-04 , Vol. 12 , N. 645784 , P. 13p.
DOI 10.3389/fmicb.2021.645784
Keyword(s) rhizosphere, soil microsites, bacterial communities, biomarkers, Brassica
Abstract Microorganisms residing on root surfaces play a central role in plant development and performance and may promote growth in agricultural settings. Studies have started to uncover the environmental parameters and host interactions governing their assembly. However, soil microbial communities are extremely diverse and heterogeneous, showing strong variations over short spatial scales. Here, we quantify the relative effect of meter-scale variation in soil bacterial community composition among adjacent field microsites, to better understand how microbial communities vary by host plant genotype as well as soil microsite heterogeneity. We used bacterial 16S rDNA amplicon sequencing to compare rhizosphere communities from four Brassica rapa cultivars grown in three contiguous field plots (blocks) and evaluated the relative contribution of resident soil communities and host genotypes in determining rhizosphere community structure. We characterize concomitant meter-scale variation in bacterial community structure among soils and rhizospheres and show that this block-scale variability surpasses the influence of host genotype in shaping rhizosphere communities. We identified biomarker amplicon sequence variants (ASVs) associated with bulk soil and rhizosphere habitats, each block, and three of four cultivars. Numbers and percent abundances of block-specific biomarkers in rhizosphere communities far surpassed those from bulk soils. These results highlight the importance of fine-scale variation in the pool of colonizing microorganisms during rhizosphere assembly and demonstrate that microsite variation may constitute a confounding effect while testing biotic and abiotic factors governing rhizosphere community structure.
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