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Dissertation/Thesis Abstract

Potential Involvement of Arabidopsis thaliana’s Berberine Bridge-Like Enzyme (Bbe-L) Family in Leaf Development and Stress Response
by Grawe, Jordyn, M.S., Southern Illinois University at Edwardsville, 2020, 69; 27957665
Abstract (Summary)

Although Berberine Bridge Enzymes (BBEs) are not well characterized, phylogenetic analysis has revealed their prevalence across many eukaryotic and bacterial species. Arabidopsis thaliana contains a family of 28 Berberine Bridge Enzyme–Like genes (BBE-Ls) of mostly unknown function, named for their structural relationship to the Berberine Bridge Enzyme from Berberis vulgaris. In the Berberis genus, these enzymes are involved in the synthesis of the secondary metabolite berberine, which is generated in response to plant stress. A. thaliana does not produce the compound berberine itself, but exogenous application results in alterations to leaf development. In addition, 12 of the 28 BBE-Ls are mis-regulated in the methylerythritol 4-phosphate (MEP) pathway mutant ggpps11-1. This isoprenoid precursor pathway mutant displays altered chlorophyll production as well as leaf margin abnormalities. The goal of this work is to address the hypothesis that BBE-Ls are involved in leaf patterning and development in A. thaliana. T-DNA insertion mutations have been obtained and confirmed for 27 of the BBE-Ls. Mutant leaf shape was examined using the LAMINA imaging program to determine if loss of individual BBE-L activity impacts leaf architecture. One bbe-l was found to be significantly smaller and radialized compared to the other mutants. Quantitative Reverse Transcriptase PCR (qRT-PCR) was performed to examine the transcript levels of the known abaxial polarity-determining gene, YABBY5, in bbe-l mutants compared to wild type. Two of the mutants tested resulted in increased relative expression of YAB5 compared to wild-type. Bioinformatic perturbation analysis of AtBBE-Ls indicate that all BBE-Ls are differentially regulated in response to biotic and abiotic stress. Also discovered through bioinformatics, AtBBE-Ls may be involved in the plant stress response, as they are co-expressed and physically interact with genes that function in stress response pathways.

Indexing (document details)
Advisor: Luesse, Darron R.
Commitee: Fowler, Thomas, Barry, Kelly
School: Southern Illinois University at Edwardsville
Department: Biological Sciences
School Location: United States -- Illinois
Source: MAI 81/12(E), Masters Abstracts International
Subjects: Biology, Bioinformatics, Biochemistry
Keywords: Arabidopsis thaliana, BBE-Like, LAMINA, Leaf development, qRT-PCR, Stress
Publication Number: 27957665
ISBN: 9798645498818
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