Date of Graduation

Summer 2016

Degree

Master of Science in Plant Science (Agriculture)

Department

College of Agriculture

Committee Chair

Wenping Qiu

Abstract

Stilbenic compounds are a group of phytoalexins that are produced by a limited number of plant species including grapevine to defend against diseases. Stilbene synthase (STS) is the key enzyme that catalyzes the biosynthesis of stilbenic compounds. Previous results indicated a significant increase in the abundance of transcripts of STS7 and STS22 genes in powdery mildew-infected Cabernet Sauvignon leaves. I isolated the promoter sequences of STS7 and STS22 from grapevine Vitis aestivalis "Norton"(Va) and Vitis vinifera "Cabernet Sauvignon"(Vv) and studied their activities in transgenic plants. The results showed high activity of VaSTS7 and VaSTS22 promoters in transgenic plant leaves at all developmental stages. VaSTS22 promoter was activated mainly along the veins, whereas VaSTS7 promoter was activated in leaf tissues in transgenic plants. Both VaSTS22 and VvSTS22 promoters showed higher activity than VaSTS7 promoter in transgenic plant leaves at 10 days post inoculation with powdery mildew, but neither VaSTS7 nor VvSTS22 promoter showed significant changes in transgenic plants after inoculation. These assays demonstrated that STS7 and STS22 promter differently regulated a reporter gene in roots, leaves, and also in response to salicylic acid and powdery mildew in transgenic plants. My results provided new knowledge on the involvement of STS genes in defense against biotic and abiotic factors.

Keywords

plant defense system, powdery mildew, Botrytis cinerea, stilbenic compounds, stilbene synthase, promoter

Subject Categories

Plant Sciences

Copyright

© Lianhua Lianhua Xu

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