Date of Award

2016

Document Type

Thesis

Degree Name

Bachelors

Department

Natural Sciences

First Advisor

Ryba, Tyrone

Area of Concentration

Biology

Abstract

Studying the plant innate immune system is important to address hunger and malnutrition problems worldwide. Plants have two immune systems to defend themselves against pathogen attack. Initially, pattern-triggered immunity (PTI) is induced upon membrane receptor recognition of immunogenic ligands. Pathogenic bacteria deliver effector proteins into the plant cell that disturb this immune response to promote disease. Some plants express resistance proteins that detect the presence of specific effectors leading to effector-triggered immunity (ETI). Previous transcriptomic analysis monitored tomato gene expression changes in response to Pseudomonas syringae pv. Tomato infection to characterize differences between PTI and ETI. This study aimed to expand our understanding of plant immunity by characterizing PTI and ETI using high-throughput bottom-up global proteomics. Previous transcriptomic analysis also identified two genes as potential PTI reporter genes. Using these potential reporter genes, this investigation aimed to develop and validate promoter-β-glucuronidase (GUS) fusion constructs for PTI-specificity. Using TMTsixPlex quantitative proteomics approach, 5209 proteins were identified in tomato leaves and 562 of them were determined to be responsive to PTI, ETI, or both. Analogies between transcript and proteome expression data, GO term enrichment, and bibliographic references were used to provide information about the potential functions of differentially expressed proteins during immunity response and to characterize the mechanistic differences between ETI and PTI. Furthermore, this study identified multiple protein kinases whose expression and enrichment data suggest they play important signaling roles during PTI and ETI. Nicotiana benthamiana and Solanum lycopersicum leaves were transformed with Solyc02g0699960 and Solyc04g077180 promoter-GUS constructs. GUS was used as a histochemical readout of expression in response to PTI-inducing treatments. Expression profiles were analyzed to determine construct functionality as a PTI reporter. Results indicated successful cloning and functional promoters. However, non-PTI-specific expression of the reporters was observed and further experiments are necessary to determine PTI-specificity.

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