Date of Award

5-2015

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Biology

First Advisor

Dr. ynan Abu Qamar

Second Advisor

Dr. Rabah Iratni

Third Advisor

Dr. Esam Uddin Mohammed Saeed

Abstract

Signaling pathways controlling biotic and abiotic stress responses may interact synergistically or antagonistically. To identify the similarities and differences among responses to diverse stresses, we analyzed previously published microarray data on the transcriptomic responses of Arabidopsis thaliana to infection with Botrytis cinerea (a biotic stresses). Our analyses showed that at least at early stages B. cinerea inoculation, 1498 genes were up-regulated (B. cinerea up-regulated genes; BUGS) and 1138 genes were down-regulated (B. cinerea down-regulated genes; BUGS). We showed a unique program of gene expression was activated in response each biotic and abiotic stress, but that some genes were similarly induced or repressed by all of the tested stresses. Of the identified BUGS, 25%, 6% and 12% were also induced by cold, drought and oxidative stress, respectively; whereas 33%, 7% and 5.5% of the BUGS were also down-regulated by the same abiotic stress. Coexpression and protein-protein interaction network analyses revealed a dynamic range in the expression levels of genes encoding regulatory proteins. Analysis of gene expression in response to electrophilic oxylipins suggested that these compounds are involved in mediating responses to B. Cinerea infection and abiotic stress through TGA transcription factors. Our results suggest an overlap among genes involved in the responses to biotic and abiotic stresses in A. thaliana. Changes in the transcript levels of genes encoding components of the cyclopentenone signaling pathway in response to biotic and abiotic stresses suggest that the oxylipin signal transduction pathway plays a role in plant defense. Identifying genes that are commonly expressed in response to environmental stresses, and further analyzing the functions of their encoded products, will increase our outstanding of the plant stress response. This information could identify targets for genetic modification to improve plant resistance to multiple stresses.

Included in

Biotechnology Commons

Share

COinS