Kai Han

Document Type

Thesis - University Access Only

Award Date

1997

Degree Name

Master of Science (MS)

Department / School

Plant Science

Abstract

The differential display technique established by Liang and Pardee (1992) was employed in the identification of genes associated with freeze resistance. Two near-isogenic mutant lines, SDm16029 (freeze resistant, FR) and SDm16169 (freeze susceptible, FS), of hard red winter wheat were used in this study. Partial cDNAs were generated from mRNA of crown tissue by RT-PCR (reverse transcription followed by polymerase chain reaction). The cDNA fragments from the two mutant lines, with or without four-week cold treatment, were compared side-by-side on a 6% polyacrylamide DNA sequencing gel. A majority of the cDNA bands were identical between two mutant lines and treatments as expected since they share near-isogenic background. However, a few distinct cDNA bands showed cold regulation. One fragment of around 360 bp showed up-regulation and was expressed at a higher level in the FR line compared with the FS line after four-week cold treatment. This cDNA band was cut from the gel, eluted and reamplified. The amplified product was inserted in the vector pCR-script, sequenced, and named CA304. Northern hybridization analysis showed that CA304 hybridizes with two transcripts, 1.1 kb and 2. 7 kb. Both transcripts accumulate in response to 4wk cold treatment (2°C) of FR and FS lines with higher levels in FR than in the FS line. Preliminary data suggests that gene ca304 is not induced by drought, salt or heat stresses. A database search showed no sequence having high homology with that of ca304. To my knowledge, pCA304 is the first cDNA clone that has been isolated for a cold -regulated gene during the epressed later stage of cold acclimation (4 wk), and that has putative association with freeze resistance. Therefore, this gene is a good candidate for further study of freeze resistance.

Library of Congress Subject Headings

Winter wheat -- Frost resistance

Winter wheat -- Genetics

DNA

Format

application/pdf

Number of Pages

63

Publisher

South Dakota State University

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