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A Role for Inositol Pyrophosphates in Arabidopsis Defense Against Herbivorous Insects

Inositol pyrophosphates (PP-InsPs) are a family of molecules recently discovered to be implicated in a number of plant pathways such as auxin regulation, phosphate (Pi) sensing, and jasmonate-(JA)-regulated plant defense. Transgenic plants that overexpress inositol tetrakisphosphate 1-kinase (ITPK1) and the kinase domain of the dual domain diphosphoinositol pentakisphosphate kinase 2 (VIP2KD) have been previously studied to display uniquely elevated PP-InsPs. Here it is reported that the JA defense pathway is constitutively upregulated in VIP2KD OX plants, resulting in a lower rate of herbivory on the transgenic plants. ITPK1 OX, although also having elevated PP-InsPs, was fed upon by insect larvae comparably to Wild-Type Arabidopsis (WT). The data implicate VIP2, InsP8, and possibly the PP-InsP biosynthesis as a whole. / Master of Science in Life Sciences / Plants and insects have been evolving defenses against each other since they first emerged together post-Cambrian explosion. They each have evolved targeted metabolic pathways to produce chemicals with which to repel, harm, or even trick one another. In Arabidopsis thaliana, one of the most widely studied defense mechanisms is the jasmonic acid defense pathway, which responds to the herbivory of insects like caterpillars by setting off an array of genetic switches. The plant enters a stressed state wherein it represses the genes focused on growth and development and encourages the expression of genes focused on protecting vital resources and thwarting the attacker. This work examines a connection between the phosphate-sensing pathways and the jasmonic acid defense pathways in plants, and the following data show that plants with elevated inositol pyrophosphates (a phosphate storage molecule) are resistant to the herbivory of common pest caterpillars.

Identiferoai:union.ndltd.org:VTETD/oai:vtechworks.lib.vt.edu:10919/118401
Date12 March 2024
CreatorsVanwinkle, Ashlynn Brook
ContributorsBiochemistry, Gillaspy, Glenda E., Tholl, Dorothea, Vinauger Tella, Clement
PublisherVirginia Tech
Source SetsVirginia Tech Theses and Dissertation
LanguageEnglish
Detected LanguageEnglish
TypeThesis
FormatETD, application/pdf
RightsIn Copyright, http://rightsstatements.org/vocab/InC/1.0/

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