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Ellyn Evans_Dissertation_7.11.22.pdf (9.08 MB)

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Characterization of Linum usitatissimum Plasticity and Soil Microbiome Communities: Insights from Salt and Nutrient Stress

Evans, Ellyn
http://orcid.org/0000-0003-3581-2802
http://rave.ohiolink.edu/etdc/view?acc_num=case1657544970458109

Abstract Details

2022, Doctor of Philosophy, Case Western Reserve University, Biology.
Flax is a dual-purpose crop for both the seeds and linseed oil; as with other major crops, abiotic stress imparted by both varying environmental conditions and climate change have significant effects on the plant’s viability. In particular, nutrient deprivation is well-characterized at both the phenotypic and molecular level in four varieties of flax (Bethune, Pl, S, and L). While, salt stress susceptibility and tolerance is much less understood in the aforementioned flax varieties. The primary aims of this project included: 1. characterize the phenotype and genotype of four flax varieties under salt stress to be compared to nutrient deprivation, 2. determine the transcriptomic changes of the four flax varieties under salt stress versus nutrient deprivation, and 3. characterize the flax soil microbiome (rhizosphere) to identify punitive plant growth promoting rhizobacteria (PGPR) and/or well-known PGPR. The first portion of the project focused on collecting data pertaining to several phenotypic metrics (height, branching, flowering, and seed setting/collection), as well as genotypic characteristics. Such genotypic regions of interested included LIS-1 to determine if this region was inserted under salt stress, as well as, characterize of several molecular markers (scaffold regions) to identify genotypic patterns specific to salt stress. While, the second portion consisted of RNA sequencing of Bethune, Pl, S and L under salt stress (0.08 M NaCl and 0.15 M NaCl). Additionally, RNA sequencing of S and L under nutrient deprivation was conducted. These data illustrated that many candidate transcripts are those implicated in general stress response, as there was not consistent differential expression per each stress condition within or between flax varieties. Finally, the third portion consisted of 16S ITS V4 sequencing which allowed for metagenomic analysis of the Bethune, Pl, S, and L soil microbiomes under 0.08 M NaCl, 0.015 M NaCl, and nutrient deprivation. This allowed for us to identify any novel microbes, those specific to either salt stress or nutrient deprivation, along with the impact of the flax genotype on the soil microbiome composition. Such analyses led to the discovery that the nutrient deprived samples for all four flax varieties have strong similarities in microbial diversity and abundance, but such a pattern was not observed for either salt stress condition. Collectively, all aspects of the project described above, allowed for identification of unique changes to each flax variety and support the notion that response to the abiotic stresses studied are dependent on the flax variety. The genomic analysis illustrated that there are noteworthy differences for salt stress versus nutrient stress for each variety. Transcriptomic profiling highlighted the fact that there are shared differentially expressed genes, indicative of general stress response. While, there is not a specific set of transcripts pertaining to each of the three stress conditions. Finally, the soil rhizosphere composition is dependent on both the stress condition and flax genotype. As some microbes are specific to only one flax variety, but the compositions are not synonymous per each stress across the four varieties.
Christopher Cullis (Advisor)
218 p.
Agriculture; Biochemistry; Bioinformatics; Biology; Botany; Developmental Biology; Environmental Science
flax; abiotic stress; nutrient stress; salt stress; plasticity; soil microbiome; PGPR; transcriptomics; genomic rearrangements; 5S rDNA; phenotyping

Recommended Citations

Citations

  • Evans, E. (2022). Characterization of Linum usitatissimum Plasticity and Soil Microbiome Communities: Insights from Salt and Nutrient Stress [Doctoral dissertation, Case Western Reserve University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=case1657544970458109

    APA Style (7th edition)

  • Evans, Ellyn. Characterization of Linum usitatissimum Plasticity and Soil Microbiome Communities: Insights from Salt and Nutrient Stress . 2022. Case Western Reserve University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=case1657544970458109.

    MLA Style (8th edition)

  • Evans, Ellyn. "Characterization of Linum usitatissimum Plasticity and Soil Microbiome Communities: Insights from Salt and Nutrient Stress ." Doctoral dissertation, Case Western Reserve University, 2022. http://rave.ohiolink.edu/etdc/view?acc_num=case1657544970458109

    Chicago Manual of Style (17th edition)

case1657544970458109
410
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