Honors Program Theses


Open Access Honors Program Thesis

First Advisor

Tilahun Abebe


Barley--Effect of drought on; Barley--Genetics;


The following study analyzed the role of the gamma-aminobutyric acid transaminase (GABAT) gene in the response of barley plants to drought stress. Expression of GABAT in barley was suppressed using virus-induced gene silencing (VIGS). In VIGS, an RNA virus is used to replicate a small portion of the target RNA. In this study, barley stripe mosaic virus (BSMV), that carries a piece of the GABAT gene to infect barley, was used. As the virus replicates inside infected barley plants, it also makes RNA that is complementary to GABAT messenger RNA (mRNA) that is normally made by the host. The presence of this double-stranded RNA triggers the RNA interference (RNAi) pathway, which degrades GABAT, inhibiting its translation. The silenced plants were assessed for their response to drought stress. The amount of GABAT mRNA in the silenced plants was estimated using real-time PCR. The results showed that expression of GABAT was down-regulated by 65-77% in the silenced plants. The silenced plants exposed to drought conditions displayed more drought symptoms than those with a normal amount of GABAT enzyme. This indicates that the GABAT gene plays an important role in the drought tolerance of barley.

Year of Submission



Department of Biology

University Honors Designation

A thesis submitted in partial fulfillment of the requirements for the designation University Honors

Date Original


Object Description

1 PDF file (i, 25 pages)



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