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Dissertation/Thesis Abstract

Contribution of 14-3-3λ in the Resilience to Drought Stress by Affecting the Biosynthesis of Anthocyanins in Arabidopsis Thaliana and the Resurrection Plant Selaginella Lepidophylla
by Nabbie, Fizal N., Ph.D., University of the Sciences in Philadelphia, 2017, 105; 10631482
Abstract (Summary)

Manipulating the phenylpropanoid (Pp) pathway has been of great focus to bio-engineers as this pathway is responsible for production of many compounds that are important to human health for their known antioxidant, anti-viral, anti-inflammatory, anti-allergenic and vasodilatory properties. The secondary by products of the Pp pathway are important for the physiological well-being of the plant as it contributes to plant’s ability to tolerate changing environment. Plant bio-engineering, involves manipulating gene expression of proteins that regulate functional proteins which are known to attribute to stress tolerance. Our research focused on one such regulatory protein called the 14-3-3 lambda (14-3-3λ) protein and its effects on anthocyanin production in two different plants: a plant model Arabidopsis thaliana (A. thaliana, Columbia-0), and a naturally drought tolerant resurrection plant Selaginella lepidophylla ( S. lepi). Due to their structural characteristics the family of 14-3- 3 proteins bind to many different client proteins and hence can function as signaling factors in eukaryotes. Anthocyanins are anti-oxidants produced in plants that alter plants physiology to resist stress. The goal of this study was to establish which nodes in the anthocyanin synthesis pathways are influenced by 14-3-3λ in both A. thaliana and S. lepi . Data from this study established the steps in the Anthocyanin pathway that 14-3-3λ affects to alter anthocyanin production during normal hydration and drought stress states. Based on our published studies and experimental data we have identified that the 14-3-3λ isoform is playing a significant role in the anthocyanin pathway during drought stress. Using a reverse genetics approach, the amounts of secondary anthocyanin metabolites produced in a 14-3-3λ knockout mutant were compared to the wild-type A. thaliana during normal hydration and drought conditions. Analytical techniques such as high performance liquid chromatography (HPLC) and liquid chromatography-Mass Spectrometry (LC-MS/MS) in combination with open access databases were used for metabolite profiling. The metabolite profile lead to candidate metabolites that differed between the drought-treated and hydrated groups in the knockout mutants and wild-type. Identification of these metabolites determined the nodes of Pp pathway that were affected by 14-3-3λ, namely the enzymes chalcone synthase and chalcone isomerase. These findings in A. thaliana were expanded in the naturally drought resistant plant S. lepi using similar analytical approaches employed in A. thaliana. The results proved that 14-3-3λ affects biosynthesis of anthocyanin during drought stress in A. thaliana and S. lepi in a similar manner, hence suggesting a similar role of 14-3-3λ in the production of anthocyanins in both the plants.

Indexing (document details)
Advisor: Peethambaran, Bela
Commitee: Charalampos, Papachristou, Heindl, Jason, Piccoli, Steven, Schaefer, Frederick
School: University of the Sciences in Philadelphia
Department: Biological Sciences
School Location: United States -- Pennsylvania
Source: DAI-B 78/11(E), Dissertation Abstracts International
Subjects: Molecular biology, Cellular biology
Keywords: 14-3-3 lambda, Anthocyanin Biosynthesis, Arabidopsis thaliana, Chalcone synthase, Drought stress, Phenylpropanoid pathway
Publication Number: 10631482
ISBN: 978-0-355-01704-5
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