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Author

Li-Yun Chang

Document Type

Dissertation - University Access Only

Award Date

1993

Degree Name

Doctor of Philosophy (PhD)

Department / School

Plant Science

First Advisor

D.G. Kenefick

Abstract

Cold-regulated cDNA clones were selected from a barley cDNA library using differential screening. The library was generated from mRNA of an enriched membrane-bound (MB) polysomal fraction of 14-d cold-treated winter barley primary leaf tissue. Cold-regulated cDNA fragments were subcloned into either plasmid pUC19 or pGEM3Z. Characterization of cold-regulated cDNA clones was based on the degree of cross-homology in their DNA structure. Cross-hybridization among cDNA fragments of pGD2001, pUD8, pUD32, pUD31, pUD42, pUD12, and pGD41 arising from five distinct genes designated as HVCR1/HVCR8, HVCR2, HVCR3, HVCR4 and HVCR12/HVCR12.1. HVCR1 and HVCR8 have homologous DNA structure suggesting they may be from related but not identical genes. HVCR12 and HVCR12.1 may be identical. Results from identification of cDNA clones by transcripts and by acclimation duration showed four genes (HVCR1/HVCR8, HVCR12/HVCR12.1, HVCR2 and HVCR4) are up-regulated by cold. HVCR3 is a gene that is slightly down-regulated by cold. No detectable transcript was found for HVCR4, suggesting that the transcript may belong to a low abundant mRNA species. Additional data is required about HVCR4 to evaluate mRNA expression. The order of increased mRNA accumulation for up-regulated genes (HVCR2, HVCR12, HVCR8 and HVCR1) during tissue cold treatment was 2 1 d, 2 d, 4 d and 6 d at 2°C, respectively. After reaching this high level of expression each remained there for a 30-d cold period. From analysis of autoradiographs it appeared that HVCR3 was slightly down-regulated during cold treatment of tissue.

Library of Congress Subject Headings

Barley -- Frost resistance
Barley -- Genetics
DNA -- Synthesis
Molecular cloning

Format

application/pdf

Publisher

South Dakota State University

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