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THE IDENTIFICATION AND ANALYSIS OF A NEW KNOTTED -LIKE HOMEOBOX GENE ISOLATED FROM LYCOPERSICON ESCULENTUM
| Title: | THE IDENTIFICATION AND ANALYSIS OF A NEW KNOTTED -LIKE HOMEOBOX GENE ISOLATED FROM LYCOPERSICON ESCULENTUM |
| Author: | SMITH, SHAWN PATRICK |
| Description: | The vegetative leaves of angiosperms have a diverse range of sizes and shapes, however the most distinctive characteristic of these leaves is whether the leaf is designated as being either simple or compound based upon the general features of its form. Simple leaves consist of a single leaf blade, whereas compound leaves have divided blades or leaflets. A number of leaf shape mutants have been identified in tomatoes that result in a variety of altered leaf shape phenotypes. One of these leaf shape mutants is lanceolate. Tomato plants heterozygous for the lanceolate mutation have a simple, lanceolate-shaped leaf. While the identity of the gene is unknown, previous studies suggest that members of a plant homeobox gene superfamily, the knotted-like homeobox knox) genes may be important for leaf development, and may account for the diversity of leaf form. The overexpression of knox genes under the control of a constitutive promoter causes changes in leaf morphology, including excessive compounding of tomato leaves. Furthermore, the misexpression of a previously identified tomato knox gene has been determined to cause two different leaf shape mutations. Therefore, I isolated a new tomato knox gene that may affect leaf form. The new partial tomato knox cDNA isolated from the young shoot tips of wild type tomato plants was designated as TKn4 (tomato knotted 4). The encoded homeodomain of TKN4 is 73% identical to the homeodomain of KN1 from maize, and thus TKn4 was classified as a class I knox gene. BLAST analysis determined that the peptide sequence of TKN4 shares 81% identity with the peptide sequence of NTH1 from Nicotiana tabacum. Furthermore, TKn4 mRNA transcripts were detected in young shoot tips and flowers of wild tomato plants, but absent from its mature leaves. A reduced level of TKn4 mRNA transcripts were detected in the young shoot tips of the lanceolate mutant tomato plants, suggesting that the TKn4 gene is altered in this particular mutation, and therefore may have a role in causing the lanceolate phenotype. |
| Permanent Link: |
http://rave.ohiolink.edu/etdc/view?acc_num=ucin1022589644
http://hdl.handle.net/2374.OX/12445 |
| Date: | 2002 |
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