Abstract Detail



Symbioses: Plant, Animal, and Microbe Interactions

Dickey, Jonathan [1].

Rhizosphere microbiome disturbance due to seasonal monsoons and consequences for microbial mediated reproductive plant traits in the Sonoran Desert.

Introduction/Questions: While often overlooked, diffuse trophic interactions among plants and their soil microbiomes can have large effects on aboveground plant traits as they regulate nutrients for plant uptake. For example, variation in bacterial richness within soil surrounding the roots (i.e., rhizosphere) can have selective effects on photosynthetic biomass. However, the extent of microbial selection on floral traits and phenology is currently unknown. Host specific microbial composition is dynamic and can be dependent on environmental and biotic interactions. Therefore, the first step to understand the outcome of varying microbial selection on floral traits is to examine how annual changes in the abiotic environment affect the structure of rhizosphere microbial communities. Linking environmentally mediated shifts in microbial composition to changes in floral traits will give realistic insight on variation in plant fitness and how mutualisms respond to multiple selective agents. Salvia lemmonii, a native to the Sky Islands, provides a unique system for plant-microbiome studies due to an elongated flowering state and large fleshy root system. Here I address the following questions: How does microbial community structure associated with the plant rhizosphere correlate with plant phenology, reproductive traits, and relative fitness? Does the intensity of seasonal monsoonal rainfall alter community structure of plant rhizospheres and contribute to variation in phenological shifts and plant fitness?  Methods/Results: By examining S. lemmonii at different developmental stages (n=35 each), I will address how variation in rhizosphere microbial structure covaries with phenology, variation in floral abundance and corolla tube length. To directly test to what extent rhizospheric microbial structure changes due to monsoon events, I removed monsoon disturbance on a subset of plants by adding rainout shelters as protection. Abundance and diversity of soil microbiota will be quantified through bacterial 16S rRNA and AMF 18S sequencing using the Illumina MiSeq workflow. I predict that rhizosphere microbiomes with more diverse communities favoring nitrogen fixation will lead to a quicker response in flowering time of plants disturbed by heavy rainfall. Accordingly, plants that receive fewer resources from the rhizosphere microbiome will have fewer flowers, diminished corollas, and higher reproductive cost. Linking environmentally and biotically mediated shifts in microbial composition to changes in floral traits will help give realistic insight on variation in plant fitness and how plant soil feedback loops are further reinforced.


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1 - The University of Tennessee Knoxville, Ecology and Evolutionary Biology, 1416 Circle Drive , Knoxville, Tennessee, 37996, United States

Keywords:
Rhizosphere Microbiome
Evolutionary Ecology
Plant-Soil Feedbacks
Molecular Ecology
community ecology.

Presentation Type: Oral Paper
Number: 0001
Abstract ID:127
Candidate for Awards:None


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