Genetic and physiological analysis of ethylene signal transduction in tomato and identification of DNA markers for the tomato high-pigment (hp) mutant /
The tomato Epi and hp-1 mutations have distinct genetic effects, yet they have one common feature in that they regulates signal transduction systems, hormonal and light respectively. As such both mutations can serve as useful tools to study signal transduction mechanisms in plants. The tomato Epi mu...
| Main Author: | |
|---|---|
| Format: | Thesis Book |
| Language: | English |
| Published: |
[Place of publication not identified] :
[publisher not identified] ;
1999.
|
| Subjects: | |
| Online Access: | http://proxy.library.tamu.edu/login?url=http://proquest.umi.com/pqdweb?did=730293911&sid=1&Fmt=2&clientId=2945&RQT=309&VName=PQD |
| Summary: | The tomato Epi and hp-1 mutations have distinct genetic effects, yet they have one common feature in that they regulates signal transduction systems, hormonal and light respectively. As such both mutations can serve as useful tools to study signal transduction mechanisms in plants. The tomato Epi mutant displays a constitutive ethylene response phenotype in some ways similar to the Arabidopsis CTR1 (constitutive triple response) mutant. Others have shown that exogenous application of inhibitors of ethylene biosynthesis and perception did not revert the mutant to normal phenotype, indicating that Epi is likely to represent a lesion in ethylene signal transduction. Consequently, the EPI gene is an obvious candidate for a tomato homologue of CTR1 (TCTR1). The present study showed that the TCTR1 cDNA was isolated and mapped to chromosome 2 of the tomato genome. In contrast, Epi maps to tomato chromosome 4. This showed that EPI does not represent an allele of the tomato homologue of the Arabidopsis CTR1 gene. Nevertheless, it remains possible that Epi represents a related gene. An alternate possibility is that TCTR1 is not the functional homologue of CTR1. To begin to address this possibility, TCTR1 genomic sequence was analyzed. The genomic sequence of TCTR1 is composed of 18 exons. In addition, a high degree of sequence homology between TCTR1 and CTR1 gene was observed, suggesting that TCTR1 may play a similar role as a negative regulator of the ethylene signal transduction pathway in tomatoes. This hypothesis can ultimately verified by transgenic experiments modulating expression of the of TCTR1 gene. While the Epi locus regulates ethylene signal transduction, the high pigment-1 (hp-1) locus regulates light signal transduction. The HP-1 gene product ants as a negative regulator of the phytochrome and cryptochrome signaling pathways in tomatoes. As a first step in the isolation of HP-1 gene, one RAPD marker is tightly linked to hp-1 locus. In a contrast to previous reports, this marker resides on chromosome two of tomatoes rather than chromosome 12. Eventual HP-1 and EPI gene isolation will provide insights toward plant signal transduction mechanisms and will be useful for comparative analysis of these processes with additional plant species. |
|---|---|
| Item Description: | Vita. "Major Subject: Plant Physiology and Plant Biotechnology". |
| Physical Description: | x, 137 leaves : illustrations ; 28 cm. Issued also on microfiche from University Microfilm Inc. |
| Bibliography: | Includes bibliographical references (leaves 104-036). |