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Author ORCID Identifier

N/A

AccessType

Open Access Dissertation

Document Type

dissertation

Degree Name

Doctor of Philosophy (PhD)

Degree Program

Plant, Soil & Insect Sciences

Year Degree Awarded

2015

Month Degree Awarded

September

First Advisor

Om Parkash

Subject Categories

Agricultural Science | Agriculture | Agronomy and Crop Sciences | Biotechnology | Plant Biology

Abstract

Environmental stresses are the one of the main reasons for the decline of crop production worldwide. In the past years, a major focus has been on improving plant species and their tolerance towards these stresses but not much has been achieved because of the limited knowledge of the gene/network of genes that might be involved in providing tolerance to such multiple abiotic stresses. Recently, members of Stress Associated Protein (SAP) family in plants have been shown to impart tolerance to multiple abiotic stresses. There are 14 SAP genes in Arabidopsis thaliana and these proteins contain A20, AN1 and C2H2 zinc finger domains. AtSAP13, a member of the SAP family, carries two AN1 zinc finger domains and an extra Cys2-His2 domain. AtSAP13 showed differentially regulation in response to multiple abiotic stresses such as toxic metals arsenic (As), cadmium (Cd), and zinc (Zn), drought, and salt. When overexpressed in Arabidopsis and Brassica juncea, it showed strong tolerance to these stresses. However, the mode of action of this SAP member in providing tolerance to multiple abiotic stresses is largely unknown. In-silico analysis of the promoter sequences upstream of ATG start codon of AtSAP13 using PLACE database predicted the presence of various abiotic stress related cis regulatory elements. We hypothesized that the expression of AtSAP13 gene might be regulated via the interaction of cis-elements present in the AtSAP13 promoter with abiotic stress related trans factors via protein-DNA interactions under different abiotic stresses. Through yeast one hybrid assay (Y1H), we have proved this hypothesis and identified several transcription factors such as DREB, ERE, ZIP, HSE etc that are interacting with the AtSAP13 promoter. These interactions were analyzed through Electrophoretic mobility shift assay (EMSA) to understand the molecular and biochemical functioning of AtSAP13. Further, Camelina sativa, a member of Brassicaseae family and closely related with Arabidopsis, has been proposed as an ideal biofuel crop. In order to improve it’s adaptability to wider geographical ranges and marginal land, we have characterized and overexpressed endogenous SAP13 in C. sativa in providing tolerance to various stresses. We have identified and cloned CsSAP13 in C. sativa. Resulting transgenic plants showed enhanced biomass and seed yield under multiple abiotic stresses. The knowledge and information gained here will not only be applied on agricultural crops that will be better able to withstand such abiotic stresses and still produce sustainable yield but will also help to grow crops for food and biomass production on barren lands, thus making them more cultivable over time. Therefore, the proposed research could have a significant impact on global food security, biofuel production, and human and environment health enhancement.

DOI

https://doi.org/10.7275/7461767.0

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