Characterization of an Auxin-Inducible Proteinase Inhibitor gene from Lycopersicon esculentum Mill cv VFN8 /
Phytohormones can affect major changes in the development of
| Main Author: | |
|---|---|
| Format: | Thesis Book |
| Language: | English |
| Published: |
[Place of publication not identified] :
[publisher not identified] ;
1994.
|
| Subjects: | |
| Online Access: | http://proxy.library.tamu.edu/login?url=http://proquest.umi.com/pqdweb?did=741966391&sid=1&Fmt=2&clientId=2945&RQT=309&VName=PQD |
| Summary: | Phytohormones can affect major changes in the development of plant tissues, such as increased cell division and elongation and specific developmental changes such as induction of new roots. Concomitant with such changes in plant morphology are alterations in expression levels of various transcripts. While the phenotypic effects of auxin have been well studied, the molecular basis of auxin action is not known. Incubation of detached tomato roots in 5 pM naphthalene acetic acid (NAA), a synthetic auxin, resulted in an approximately tenfold increase in the number of lateral root initials. A CDNA, corresponding to a transcript that displays increased levels in response to NAA, was identified by differential screening of a CDNA library constructed from RNA from auxin- treated roots. Induction of this transcript occurs on a time scale similar to the auxin-induced initiation of lateral roots. This CDNA clone (TR8) has sequence similarity to proteinase inhibitor II (PI-11) of tomato and potato and was used to identify a corresponding genomic clone. Sequence analysis of a cloned 4.3 kb Sall fragment (ARP19), revealed an open reading frame of 223 amino acids encoding a deduced protein of 24.7 kDa. Protein extracts from bacteria expressing this gene inhibited trypsin activity by approximately 50%. We have designated the TR8-related gene ARPI, for Auxin-Regulated-Proteinase-Inhibitor. The region 5' to the transcription start site contained a sequence with structural features similar to those of transposable elements. This putative element (Lyt]) is present in approximately 40 copies in tomato species that have red fruit and appears to reduce ARPI expression in a progenitor line of the cultivated tomato. A Inscriptional fusion gene consisting of 2875 hp of the 5' flanking DNA from ARPI, fused to the E coli B-glucuronidase (GUS) coding region, was expressed in tomato. GUS activity was primarily limited to root cortex tissue, lateral root initials and root meristems and increased in roots treated with NAA, abscisic acid, benzyl adenine and ethylene, but decreased in roots treated with gibberellic acid. The GUS message was not induced to the same extent as the endogenous ARPI message by auxin treatment, but showed a similar pattern of tissue specificity. |
|---|---|
| Item Description: | Vita. "Major Subject: Biology". In title, symbols and numerals are used. |
| Physical Description: | vi, 62 leaves : illustrations ; 28 cm. Issued also on microfiche from University Microfilms Inc. |
| Bibliography: | Includes bibliographical references. |