Abstract
Plant-associated microbial communities have diverse phenotypic effects on their hosts that are only beginning to be revealed. We hypothesized that morpho-physiological variations in the tropical tree Tabebuia heterophylla, observed on different geological substrates, arise in part due to microbial processes in the rhizosphere. We characterized the microbiota of the rhizosphere and soil communities associated with T. heterophylla trees in high and low altitude sites (with varying temperature and precipitation) of volcanic, karst and serpentine geologies across Puerto Rico. We sampled 6 areas across the island in three geological materials including volcanic, serpentine and karst soils. Collection was done in 2 elevations (>450m and 0-300m high), that included 3 trees for each site and 4 replicate soil samples per tree of both bulk and rhizosphere. Genomic DNA was extracted from 144 samples, and 16S rRNA V4 sequencing was performed on the Illumina MiSeq platform. Proteobacteria, Actinobacteria, and Verrucomicrobia were the most dominant phyla, and microbiomes clustered by geological substrate and elevation. Volcanic samples were enriched in Verrucomicrobia; karst was dominated by nitrogen-fixing Proteobacteria, and serpentine sites harbored the most diverse communities, with dominant Cyanobacteria. Sites with similar climates but differing geologies showed significant differences on rhizobiota diversity and composition demonstrating the importance of geology in shaping the rhizosphere microbiota, with implications for the plant’s phenotype. Our study sheds light on the combined role of geology and climate in the rhizosphere microbial consortia, likely contributing to the phenotypic plasticity of the trees.
Highlights
Plant phenotypic plasticity–the capacity to produce more than one phenotype from a single genotype–represents a plant’s response to environmental conditions [1,2,3,4,5], including nutrient availability and climatic conditions such as temperature and moisture [6]
The 18 trees used to characterize T. heterophylla’s rhizosphere microbiome yielded ~13.8 million non-chimeric 16S ribosomal RNA (rRNA) sequence reads with an average of 383,640 sequences per sample
We found less species richness in low elevation sites, where temperature was higher and precipitation was lower (Table 1), especially for bulk soil compared to rhizosphere (Fig 2A, Site 2 (S2) Fig)
Summary
Plant phenotypic plasticity–the capacity to produce more than one phenotype from a single genotype–represents a plant’s response to environmental conditions [1,2,3,4,5], including nutrient availability and climatic conditions such as temperature and moisture [6]. Rhizobiota of the tropical tree Tabebuia heterophylla (project title “Microbial community contributions to stress adaptation and plasticity in the tropical tree Tabebuia heterophylla”, to FGV). Additional support was provided by PR-INBRE (NIH/NIGMS- award number P20 GM103475) (to FGV), a CREST Grant (NSF-HRD 0734826) to the University of Puerto Rico-Rıo Piedras Campus (to ESV), and a NIMHDRCMI grant U54 MD007600 from RCMI. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
