Isolation and expression analysis of genes induced by water deficit stress in loblolly pine (Pinus taeda L.) /
Water deficit stress (WDS) is one of the most important
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| Format: | Thesis Book |
| Language: | English |
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[Place of publication not identified] :
[publisher not identified] ;
1996.
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| Subjects: | |
| Online Access: | http://proxy.library.tamu.edu/login?url=http://proquest.umi.com/pqdweb?did=739669111&sid=1&Fmt=2&clientId=2945&RQT=309&VName=PQD |
| Summary: | Water deficit stress (WDS) is one of the most important factors affecting survival and growth of loblolly pine (Pinus taeda). A study was undertaken in order to isolate and characterize WDS-responsive genes for genetic engineering of loblolly pine trees for marginal and semi-arid regions. During this study period, four WDS-responsive cDNAs (1p3, 1p8, 1p15, 1p20) were isolated and characterized. These clones show distinct patterns of gene expression under WDS conditions. Sequence analysis revealed that 1p3 is homologous to a stress related gene. The putative LP8 protein is a calcium-binding protein. The 1p15 is proposed to code for an H2A component of histones. The predicted LP20 protein is similar to Wilm's tumor suppresser protein. Southern blot and RT-PCR analysis revealed that 1p3 belongs to a small multigene family. The genomic clone of 1p3 (1p3- 1) was isolated, characterized and sequenced. The sequence comparison showed that 1p-3-1 is a related member of 1p3 gene family. RT-PCR using common primers led to the identification of two additional members of the gene family. All the four members of the gene family show distinct patterns of expression under WDS situations. The transcription start site for the 1p3-1 genomic clone was mapped. The genomic clone had 1026 bases of promoter region with 591 bases in the 31 untranslated region. It has a putative intron, spanning a region of 275-452 bp. The promoter region of the 1p3-1 genomic clone was translationally fused to a uidA reporter gene. Transient expression studies using the P. ellioti cell suspension cultures revealed that 1p3(P) was induced in response to WDS. Exo-deletion analysis of 1p3(P) suggested the presence of a negative regulatory element between the -1026 and -745 region. The activity of 1p3(P) was observed in various tissues in transgenic tobacco in the T0 generation. This study is another step towards understanding the WDS-response in loblolly pine in achieving our long term goal of genetically engineered tree species for increased WDS tolerance. |
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| Item Description: | Vita. "Major Subject: Plant Physiology". |
| Physical Description: | xiv, 144 leaves : illustrations ; 28 cm. Issued also on microfiche from University Microfilms Inc. |
| Bibliography: | Includes bibliographical references: pages 118-143. |