Title page, table of contents and abstract only. The complete thesis in print form is available from the University of Adelaide Library. / Cotton fibre growth and development are regulated by the expression of several thousand genes in the fibre cell. These genes are often expressed in both cotton fibres and other plant tissues, although a proportion are 'fibre-specific' (expressed predominantly or exclusively in the fibre). Many fibre-specific genes have important functions in fibre development, and their expression is generally regulated at the level of transcription. However, the mechanisms that restrict gene expression to the cotton fibre have not been well characterised. An understanding of these mechanisms is central to a molecular model of fibre development, and may be important in the generation of improved cotton varieties with fibre-specific trans gene expression. The aim of this project was to identify the promoter sequences and transcription factors involved in regulating the fibre-specific expression of FSltp6, a gene encoding a cotton lipid transfer protein (LTP). The FSltp6 gene is abundantly and specifically transcribed in elongating cotton fibres. In this project, the fibre-specificity of the FSltp6 promoter was analysed using constructs containing the FSltp6 promoter sequence driving expression of the reporter gene -glucuronidase (GUS). Cotton fibres and other cotton tissues were transiently transformed with an FSltp6::GUS construct and analysed for GUS expression. The FSltp6 promoter restricted GUS expression primarily to the cotton fibre. Successive 5' deletions of the FSltp6 promoter were then used to isolate the regions necessary for fibre-specific expression. An 84 bp fibre-specificity region (FSR) was found to be essential for GUS expression exclusively in the cotton fibre, while a 49 bp region was necessary for expression in any of the tissues tested. The fibre-specificity of the FSltp6 promoter was also analysed by the stable transformation of tobacco with FSltp6::GUS. The transgenic tobacco plants demonstrated strong GUS expression in the leaf trichomes. This result provided further support for the fibre-specificity of the FSltp6 promoter and (in line with previous studies) suggested the utility of tobacco trichomes as a model for cotton fibre development. A yeast one-hybrid assay was used to identify transcription factors that may regulate fibre-specific expression by interacting with the FSR. This experiment identified three novel classes of cotton protein with potential roles in fibre specificity: HMGA-like proteins, Mutator transposase-like proteins and an AT -hook protein. The full-length cDNA of the AT -hook protein was isolated and analysed for its potential function as a transcription factor and regulator of fibre-specificity. This project has identified a promoter region and several novel transcription factors with a potential role in the regulation of fibre-specific gene expression. These results provide further insight into the molecular regulation of gene transcription in cotton fibres. Application of these results in the generation of transgenic cotton may produce varieties with enhanced gene expression in the cotton fibre. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1188821 / Thesis (Ph.D.) -- University of Adelaide, School of Molecular and Biomedical Science, 2005

Putative cotton cDNA clones and cognate genomic clones for a palmitoyl-acyl carrier protein (ACP) thioesterase (PATE) and an osmotin-like pathogenesis-related 5 (PR5) protein have been isolated and characterized. PATE is a class B fatty acid thioesterase with specificity for saturated long-chain fatty acids such as palmitate, and is implicated as a key enzyme to be targeted for regulation of fatty acid synthesis in order to alter cotton seed oil profiles. A nearly full-length 1.7-kb cDNA clone was isolated using a hybridization probe derived from an Arabidopsis PATE cDNA clone designated TE 3-2. A 17-kb genomic segment encompassing the PATE gene was also isolated, which has six exons and five introns with high sequence identity with other FatB cDNA/gene sequences. The deduced PATE preprotein amino acid sequence of 413 residues has putative signal sequences for targeting to the chloroplast stroma. PR5 proteins called osmotins are made in response to fungal pathogen stress or osmotic stress (water deprivation or salt exposure). Osmotins may actually form pores in fungal membranes, leading to osmotic rupture and destruction of the fungal cells. A cotton osmotin-like PR5 cDNA insert of 1,052 base-pairs was isolated and shown to encode a preprotein of 242 amino acids and is predicted to be secreted to the extracellular matrix as a neutral isoform. The deduced amino acid sequence has 16 cysteine residues that are highly conserved in osmotin-like proteins and are important in stabilizing the three-dimensional structure seen in thaumatin, zeamatin, and PR5-d. The intronless cognate cotton genomic clone has two putative ethylene response elements (GCC boxes) found in other PR5 gene promoter regions, as well as several tentative promoter/enhancer elements possibly involved in spatial/temporal gene expression.

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This item was digitized as part of the Million Books Project led by Carnegie Mellon University and supported by grants from the National Science Foundation (NSF). Cornell University coordinated the participation of land-grant and agricultural libraries in providing historical agricultural information for the digitization project; the University of Arizona Libraries, the College of Agriculture and Life Sciences, and the Office of Arid Lands Studies collaborated in the selection and provision of material for the digitization project.

This item was digitized as part of the Million Books Project led by Carnegie Mellon University and supported by grants from the National Science Foundation (NSF). Cornell University coordinated the participation of land-grant and agricultural libraries in providing historical agricultural information for the digitization project; the University of Arizona Libraries, the College of Agriculture and Life Sciences, and the Office of Arid Lands Studies collaborated in the selection and provision of material for the digitization project.

This item was digitized as part of the Million Books Project led by Carnegie Mellon University and supported by grants from the National Science Foundation (NSF). Cornell University coordinated the participation of land-grant and agricultural libraries in providing historical agricultural information for the digitization project; the University of Arizona Libraries, the College of Agriculture and Life Sciences, and the Office of Arid Lands Studies collaborated in the selection and provision of material for the digitization project.

This item was digitized as part of the Million Books Project led by Carnegie Mellon University and supported by grants from the National Science Foundation (NSF). Cornell University coordinated the participation of land-grant and agricultural libraries in providing historical agricultural information for the digitization project; the University of Arizona Libraries, the College of Agriculture and Life Sciences, and the Office of Arid Lands Studies collaborated in the selection and provision of material for the digitization project.

This item was digitized as part of the Million Books Project led by Carnegie Mellon University and supported by grants from the National Science Foundation (NSF). Cornell University coordinated the participation of land-grant and agricultural libraries in providing historical agricultural information for the digitization project; the University of Arizona Libraries, the College of Agriculture and Life Sciences, and the Office of Arid Lands Studies collaborated in the selection and provision of material for the digitization project.