Degree Type

Thesis

Date of Award

2008

Degree Name

Master of Science

Department

Theses & dissertations (Interdisciplinary)

Major

Genetics

First Advisor

David J. Hannapel

Second Advisor

Yanhai Yin

Third Advisor

Gustavo MacIntosh

Abstract

Although numerous RNAs have been detected in the phloem, few have been confirmed to move long distances. In potato, full-length mRNA of the BEL1-like transcription factor, StBEL5, moves from leaf veins through the phloem to stolon tips to activate tuber formation. BEL1-like transcription factors are ubiquitous in plants and interact with KNOTTED1-types to regulate numerous developmental processes. To explore the range of KNOTTED1- and BEL1-like mRNAs present in phloem, an analysis of the transcript profile of phloem sap was undertaken. Using a modified technique for the collection of phloem-enriched exudate from excised stems, numerous RNAs encoding these transcription factors were detected in the phloem sap from several solanceous species. All seven known BEL1-like RNAs of potato were detected in the phloem-enriched exudates of stem whereas, several stolon-abundant RNAs were not. After refining the technique to minimize contamination from wounded cells, KNOTTED1-like RNAs were detected in phloem-enriched sap of potato and BEL5 RNA was detected in sap collected from two closely related nontuber-bearing potato species and tomato. BEL5 RNA was also detected in RNA extracted from leaf veins of tobacco. The detection of these full-length mRNAs from the KNOTTED1- and BEL1-like families in phloem sap indicates that their potential role as long-distance signals seems to be much more extensive than previously known.

Publisher

Digital Repository @ Iowa State University, http://lib.dr.iastate.edu/

Copyright Owner

Brian Anthony Campbell

Language

en

Proquest ID

AAI1454640

OCLC Number

263681641

ISBN

9780549685173

File Format

application/pdf

File Size

42 pages

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