Piu Wong. / Thesis submitted in: July 2002. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2003. / Includes bibliographical references (leaves 126-146). / Abstracts in English and Chinese. / Thesis committee --- p.i / Statement --- p.ii / Abstract --- p.iii / Acknowledgement --- p.viii / General abbreviations --- p.xi / Abbreviations of chemicals --- p.xiii / List of figures --- p.xv / List of Tables --- p.xvii / Table of contents --- p.xviii / Chapter 1 --- Literature review / Chapter 1.1 --- Overviews --- p.1 / Chapter 1.1.1 --- Nutritional and economical significance of aspartate family amino acidsin human and animal nutrition --- p.1 / Chapter 1.1.2 --- Synthesis of aspartate family amino acids in plants --- p.2 / Chapter 1.2 --- Regulation of aspartate family amino acids between sink and source organs --- p.6 / Chapter 1.2.1 --- Co-ordination of genes/enzymes involved in amide amino acid metabolism to channel aspartate for aspartate family amino acid synthesis --- p.6 / Chapter 1.2.2 --- Sink-source regulation as a general mechanism in plants --- p.9 / Chapter 1.3 --- Source regulation at free amino acid level --- p.11 / Chapter 1.3.1 --- Regulation of free methionine synthesis --- p.11 / Chapter 1.3.1.1 --- Competition for OPHS between TS and CGS --- p.11 / Chapter 1.3.1.2 --- Turnover of CGS mRNA --- p.12 / Chapter 1.3.1.3 --- Post-translational regulation of CGS enzyme --- p.13 / Chapter 1.3.2 --- Regulation of lysine synthesis and catabolism --- p.15 / Chapter 1.3.2.1 --- Feedback regulation loop --- p.15 / Chapter 1.3.2.2 --- Possible intracellular compartmentalization of enzymes and metabolitesin regulating lysine level --- p.21 / Chapter 1.3.2.3 --- Co-ordination of gene/enzyme in aspartate kinase pathway in regulating flux to Lys --- p.21 / Chapter 1.3.3 --- Significance of lysine catabolism in mammals and plants --- p.24 / Chapter 1.3.3.1 --- Complex developmental regulation and stress response of LKR/SDH gene expression --- p.28 / Chapter 1.3.3.2 --- Regulation through a novel composite locus LKR-SDH --- p.28 / Chapter 1.3.3.3 --- Post-translational control of LKR-SDH activity --- p.31 / Chapter 1.3.3.4 --- Implication of two metabolic flux in Lys catabolism --- p.34 / Chapter 1.4 --- Source (free lysine) enhancement in transgenic plants --- p.36 / Chapter 1.4.1 --- Expression of feedback insensitive enzyme in transgenic plants to enhance free lysine supply in transgenic plant --- p.36 / Chapter 1.4.2 --- Reducing or eliminating lysine catabolism to enhance free lysine poolin transgenic plants --- p.40 / Chapter 1.5 --- Sink regulation --- p.41 / Chapter 1.5.1 --- Engineering transgenic plants through expression of seed storage protein (sink) --- p.41 / Chapter 1.5.2 --- "Dynamic relationship between sink protein, nitrogen metabolism and sulphur metabolism" --- p.45 / Chapter 1.6 --- Transgenic plants with improved source or enhanced sinks related to aspartate family amino acids available for our research --- p.47 / Chapter 1.6.1 --- Enhanced source: ASN1 over-expressers --- p.47 / Chapter 1.6.2 --- Enhanced source: metL transgenic plants --- p.47 / Chapter 1.6.3 --- Altered source: RNAi line --- p.47 / Chapter 1.6.4 --- Effective sink: LRP transgenic plants --- p.48 / Chapter 1.7 --- Overall concept of this study --- p.48 / Chapter 2 --- Materials and methods --- p.50 / Chapter 2.1 --- Materials and growth conditions --- p.50 / Chapter 2.1.1 --- "Plants, bacterial strains and vectors" --- p.50 / Chapter 2.1.2 --- Chemicals and reagents used --- p.53 / Chapter 2.1.3 --- Solutions used --- p.53 / Chapter 2.1.4 --- Commercial kits used --- p.53 / Chapter 2.1.5 --- Equipment and facilities used --- p.53 / Chapter 2.1.6 --- Growth condition --- p.53 / Chapter 2.1.7 --- Tagging of A. thaliana siliques of different developmental stage --- p.54 / Chapter 2.2 --- Methods --- p.55 / Chapter 2.2.1 --- Expression pattern analysis --- p.55 / Chapter 2.2.1.1 --- RNA extraction --- p.55 / Chapter 2.2.1.2 --- Generation of single-stranded DIG-labelled ASN1 DNA probes --- p.55 / Chapter 2.2.1.3 --- Testing the concentration of DIG-labelled probes --- p.56 / Chapter 2.2.1.4 --- Northern blot --- p.57 / Chapter 2.2.1.5 --- Hybridization --- p.58 / Chapter 2.2.1.6 --- Stringency washes --- p.58 / Chapter 2.2.1.7 --- Chemiluminescent detection --- p.58 / Chapter 2.2.2 --- Amino acid analysis and nitrogen determination --- p.60 / Chapter 2.2.2.1 --- Free amino acids in A. thaliana --- p.60 / Chapter 2.2.2.2 --- Phloem exudates collection from A. thaliana --- p.60 / Chapter 2.2.2.3 --- Soluble Protein quantitation --- p.61 / Chapter 2.2.2.4 --- Extraction of salt and water soluble protein from A. thaliana seeds --- p.61 / Chapter 2.2.2.5 --- Purification and amino acid analysis of protein extracts from A. thaliana seeds --- p.62 / Chapter 2.2.2.6 --- Total amino acid determination in mature dry seeds --- p.63 / Chapter 2.2.3 --- Generation of crossing progenies --- p.64 / Chapter 2.2.3.1 --- Artificial crossing of A. thaliana --- p.64 / Chapter 2.2.3.2 --- CTAB extraction of genomic DNA --- p.64 / Chapter 2.2.3.3 --- PCR screening for successful crossing --- p.65 / Chapter 2.2.4 --- Generation of transgenic plants --- p.67 / Chapter 2.2.4.1 --- Cloning of E.coli dapA gene --- p.67 / Chapter 2.2.4.2 --- Preparation of recombinant plasmid --- p.68 / Chapter 2.2.4.3 --- Gene sequencing --- p.68 / Chapter 2.2.4.4 --- Homology search of differentially expressed genes --- p.69 / Chapter 2.2.4.5 --- Construction of chimeric dapA genes (TP-Phas-dapA) --- p.69 / Chapter 2.2.4.6 --- Transformation of electro-competent Agrobacterium cell --- p.73 / Chapter 2.2.4.7 --- Transformation of A. thaliana through vacuum infiltration --- p.73 / Chapter 2.2.4.8 --- Selection of hemizygous and homozygous transgenic plants --- p.74 / Chapter 2.2.4.9 --- Expression analysis of homozygous LRP/dapA transgenic plants --- p.75 / Chapter 3 --- Results --- p.77 / Chapter 3.1 --- Characterization of ASN1 over-expressers --- p.77 / Chapter 3.1.1 --- Overexpression of the ASN1 gene enhances the sink-source relationship of asparagine transport under regular daylight cycle --- p.88 / Chapter 3.1.2 --- Spatial distribution of total free amino acids under normal daylight cycle --- p.88 / Chapter 3.1.3 --- Over-expression of the ASN1 gene affects free amino acid level quantitatively under normal daylight cycle --- p.89 / Chapter 3.1.4 --- Over-expression of the ASN1 gene affects composition of total amino acid under normal daylight cycle --- p.89 / Chapter 3.2 --- Construction of dapA transgenic Arabidopsis --- p.91 / Chapter 3.2.1 --- Construction of chimeric gene for expression of the dapA gene --- p.91 / Chapter 3.2.2 --- Transformation of p1300/Phas-dapA into Arabidopsis and selection of homozygous progenies --- p.91 / Chapter 3.3 --- Generation of transgenic plants with altered sink-source relationship through crossing and in-planta transformation --- p.96 / Chapter 3.3.1 --- Rationale in methods for generating transgenic plants with different combination of sources and sinks --- p.96 / Chapter 3.3.2 --- Screening for double homozygous progenies through crossing --- p.98 / Chapter 3.3.3 --- Screening for F1 progenies of successful crossing --- p.100 / Chapter 3.3.4 --- Selection of homozygous crossing progenies --- p.102 / Chapter 3.3.5 --- Screening for homozygous dapA/LRP transgenic plants --- p.104 / Chapter 3.4 --- Amino acid composition analysis --- p.109 / Chapter 3.4.1 --- The change of aspartate family amino acids in mature seeds of transgenic plants with altered sources --- p.113 / Chapter 3.4.2 --- The change of aspartate family amino acids in mature seeds of transgenic plants with improved sink --- p.114 / Chapter 3.4.3 --- The change of aspartate family amino acids in mature seeds of transgenic plants with improved sink --- p.115 / Chapter 4. --- Discussion / Chapter 4.1 --- Characterization of ASN1 over-expressers --- p.116 / Chapter 4.1.1 --- Possible regulation of ASN1 mRNA stability through level of asparagine --- p.117 / Chapter 4.1.2 --- Over-expression of ASN1 gene may improve nitrogen remobilisation from source to sink tissues --- p.118 / Chapter 4.1.3 --- Over-expression of ASN1 gene has modified the composition of amino acidsin sink organs --- p.119 / Chapter 4.2 --- ASN1 RNAi transgenic plants increases the relative contents of lysine in the seeds --- p.122 / Chapter 4.2.1 --- Role of ASN1 in supplying or competing aspartate in developing seeds --- p.122 / Chapter 4.2.2 --- Possible role of glutamate receptor --- p.123 / Chapter 4.3 --- Lysine catabolism may strictly control the level of lysine --- p.123 / Chapter 4.3.1 --- Possible role of lysine-tRNA in protein synthesis --- p.124 / Chapter 5. --- Conclusion and prospective --- p.125 / References --- p.126 / Appendix --- p.147

Phang Tsui-Hung. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2002. / Includes bibliographical references (leaves 146-162). / Abstracts in English and Chinese. / Thesis committee --- p.i / Statement --- p.ii / Abstract --- p.iii / Acknowledgement --- p.vi / Abbreviations --- p.viii / Table of contents --- p.xii / List of figures --- p.xviii / List of tables --- p.xx / Chapter 1. --- Literature Review --- p.1 / Chapter 1.1 --- Salinity as a global problem --- p.1 / Chapter 1.2 --- Formation of saline soil --- p.1 / Chapter 1.3 --- Urgent need to reclaim saline lands --- p.2 / Chapter 1.4 --- Cellular routes for Na+ uptake --- p.2 / Chapter 1.4.1 --- Carriers involved in K+ and Na+ uptake --- p.2 / Chapter 1.4.2 --- Channels involved in K+ and Na+ uptake --- p.4 / Chapter 1.5 --- Adverse effects of high salinity --- p.5 / Chapter 1.5.1 --- Hyperosmotic stress --- p.5 / Chapter 1.5.2 --- Ionic stress --- p.6 / Chapter 1.5.2.1 --- Deficiency of K+ --- p.6 / Chapter 1.5.2.2 --- Perturbation of calcium balance --- p.7 / Chapter 1.5.3 --- Toxicity of specific ions --- p.7 / Chapter 1.5.4 --- Oxidative stress --- p.10 / Chapter 1.6 --- Mechanisms of salt stress adaptation in plants --- p.11 / Chapter 1.6.1. --- Maintenance of ion homeostasis --- p.12 / Chapter 1.6.1.1 --- Regulation of cytosolic Na+ concentration --- p.12 / Chapter 1.6.1.2 --- SOS signal transduction pathway --- p.15 / Chapter 1.6.2 --- Dehydration stress adaptation --- p.17 / Chapter 1.6.2.1 --- Aquaporins ´ؤ water channel proteins --- p.17 / Chapter 1.6.2.2 --- Osmotic adjustment --- p.20 / Chapter 1.6.2.2.1 --- Genetic engineering of glycinebetaine biosynthesis --- p.23 / Chapter 1.6.2.2.2 --- Genetic engineering of mannitol biosynthesis --- p.27 / Chapter 1.6.3 --- Morphological and structural adaptation --- p.28 / Chapter 1.6.4 --- Restoration of oxidative balance --- p.29 / Chapter 1.6.5 --- Other metabolic adaptation --- p.31 / Chapter 1.6.5.1 --- Induction of Crassulacean acid (CAM) metabolism --- p.34 / Chapter 1.6.5.2 --- Coenzyme A biosynthesis --- p.34 / Chapter 1.7 --- Soybean as a target for studying salt tolerance --- p.36 / Chapter 1.7.1 --- Economical importance of soybean --- p.36 / Chapter 1.7.2 --- Reasons for studying salt stress physiology in soybeans --- p.38 / Chapter 1.7.3 --- Salt tolerant soybean in China --- p.39 / Chapter 1.7.4 --- Exploring salt tolerant crops by genetic engineering --- p.41 / Chapter 1.8 --- Significance of this project --- p.47 / Chapter 2. --- Materials and methods --- p.48 / Chapter 2.1 --- Materials --- p.48 / Chapter 2.1.1 --- Plant materials used --- p.48 / Chapter 2.1.2 --- Bacteria strains and plasmid vectors --- p.48 / Chapter 2.1.3 --- Growth media for soybean --- p.48 / Chapter 2.1.4 --- Equipment and facilities used --- p.48 / Chapter 2.1.5 --- Primers used --- p.48 / Chapter 2.1.6 --- Chemicals and reagents used --- p.49 / Chapter 2.1.7 --- Solutions used --- p.49 / Chapter 2.1.8 --- Commercial kits used --- p.49 / Chapter 2.1.9 --- Growth and treatment condition --- p.49 / Chapter 2.1.9.1 --- Characterization of salt tolerance of Wenfeng7 --- p.49 / Chapter 2.1.9.2 --- Samples for subtractive library preparations --- p.50 / Chapter 2.1.9.3 --- Samples for slot blot and northern blot analyses --- p.50 / Chapter 2.1.9.4 --- Samples for gene expression pattern analysis --- p.50 / Chapter 2.2. --- Methods --- p.52 / Chapter 2.2.1 --- Total RNA extraction --- p.52 / Chapter 2.2.2 --- Construction of subtractive libraries --- p.53 / Chapter 2.2.3 --- Cloning of salt-stress inducible genes --- p.53 / Chapter 2.2.3.1 --- Preparation of pBluescript II KS(+) T-vector for cloning --- p.53 / Chapter 2.2.3.2 --- Ligation of candidate DNA fragments with T-vector --- p.53 / Chapter 2.2.3.3 --- Transformation --- p.54 / Chapter 2.2.3.4 --- PCR screening --- p.54 / Chapter 2.2.4 --- Preparation of recombinant plasmid for sequencing --- p.55 / Chapter 2.2.5 --- Sequencing of differentially expressed genes --- p.55 / Chapter 2.2.6 --- Homology search of differentially expressed genes --- p.56 / Chapter 2.2.7 --- Expression pattern analysis --- p.56 / Chapter 2.2.7.1 --- Preparation of single-stranded DIG-labeled PCR probes --- p.56 / Chapter 2.2.7.2 --- Preparation of cRNA DIG-labeled probes --- p.57 / Chapter 2.2.7.3 --- Testing the concentration of DIG-labeled probes --- p.58 / Chapter 2.2.7.4 --- Slot blot --- p.58 / Chapter 2.2.7.5 --- Northern blot --- p.59 / Chapter 2.2.7.6 --- Hybridization --- p.60 / Chapter 2.2.7.7 --- Stringency washed --- p.60 / Chapter 2.2.7.8 --- Chemiluminescent detection --- p.60 / Chapter 3. --- Results --- p.61 / Chapter 3.1 --- Characterization of salt tolerance of Wenfeng7 --- p.61 / Chapter 3.2 --- Identification of salt-stress induced genes from Wenfeng7 --- p.70 / Chapter 3.2.1 --- Screening subtractive libraries of Wenfeng 7 for salt inducible genes --- p.70 / Chapter 3.2.1.1 --- Results of homology search for salt inducible genes --- p.71 / Chapter 3.2.1.2 --- Northern blot showing the salt inducibility of selected clones --- p.72 / Chapter 3.3 --- Genes expression pattern of selected salt inducible genes --- p.104 / Chapter 3.3.1 --- Expression of genes related to dehydration adjustment --- p.104 / Chapter 3.3.1.1 --- Dehydration responsive protein RD22 (Clone no.: HML806) --- p.104 / Chapter 3.3.1.2 --- Beta-amylase (Clone no.: HML767) --- p.104 / Chapter 3.3.2 --- Expression of genes related to structural modification --- p.105 / Chapter 3.3.3 --- Expression of genes related to metabolic adaptation --- p.105 / Chapter 3.3.3.1 --- Subgroup 1: Gene related to protein synthesis --- p.105 / Chapter 3.3.3.1.1 --- Translational initiation factor nsp45 (Clone no.: HML1042) --- p.105 / Chapter 3.3.3.1.2 --- Seed maturation protein PM37 (Clone no.: HML931) --- p.106 / Chapter 3.3.3.2 --- Subgroup 2: Genes related to phosphate metabolism (Clone no.: HML1000) --- p.107 / Chapter 3.3.3.3 --- Subgroup 3: Genes related to storage and mobilization of nutrient resources --- p.107 / Chapter 3.3.3.3.1 --- Vegetative storage protein A (Clone no.: HML762) --- p.107 / Chapter 3.3.3.3.2 --- Cysteine proteinase (Clone no.: HML928) --- p.107 / Chapter 3.3.3.4 --- Subgroup 4: Genes related to senescence --- p.109 / Chapter 3.3.4 --- Expression of genes encoding novel protein (Clone no.: HML782) --- p.109 / Chapter 4. --- Discussion --- p.125 / Chapter 4.1 --- Evaluation of salt tolerance of Wenfeng7 --- p.125 / Chapter 4.2 --- Isolation of salt inducible genes in Wenfeng7 --- p.127 / Chapter 4.2.1 --- Genes associated with dehydration adaptation --- p.129 / Chapter 4.2.1.1 --- Dehydration responsive protein RD22 --- p.129 / Chapter 4.2.1.2 --- Beta-amylase --- p.130 / Chapter 4.2.2 --- Genes associated with structural adaptation --- p.132 / Chapter 4.2.3 --- Genes associated with metabolic adaptation --- p.133 / Chapter 4.2.3.1 --- Subgroup 1: Genes related to protein synthesis --- p.133 / Chapter 4.2.3.2 --- Subgroup 2: Genes related to phosphate metabolism --- p.137 / Chapter 4.2.3.3 --- Subgroup 3: Genes related to storage and mobilization of nutrient resources --- p.138 / Chapter 4.2.3.4 --- Subgroup 4: Genes related to senescence --- p.140 / Chapter 4.2.4 --- Novel genes --- p.142 / Chapter 4.3 --- Brief summary --- p.142 / Chapter 5. --- Conclusion and perspectives --- p.144 / References --- p.146 / Appendix I: Screening for salt tolerant soybeans --- p.163 / Appendix II: Major equipment and facilities used --- p.165 / Appendix III: Major chemicals and reagents used in this research --- p.166 / Appendix IV: Major common solutions used in this research --- p.168 / Appendix V: Commercial kits used in this research --- p.170

by Chen Li. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2001. / Includes bibliographical references (p. 136-152). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Mode of access: World Wide Web. / Abstracts in English and Chinese.

Wong Lee. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2001. / Includes bibliographical references (leaves 152-169). / Abstracts in English and Chinese. / Thesis Committee --- p.i / Abstract --- p.ii / 摘要 --- p.iv / Acknowledgements --- p.v / Abbreviations --- p.vi / List of Figures --- p.vii / List of Tables --- p.ix / Table of Contents --- p.xi / Chapter 1 --- Literature Review --- p.1 / Chapter 1.1 --- GS-GOGAT cycle in plants and bacteria --- p.2 / Chapter 1.2 --- Roles of PII in regulation of glutamine synthetase in E. coli --- p.4 / Chapter 1.2.1 --- Regulation of GS in E. col --- p.4 / Chapter 1.2.2 --- Transcriptional regulation --- p.5 / Chapter 1.2.2.1 --- The glnALG operon / Chapter 1.2.2.2 --- Intracellular signal through PII and Utase-UR / Chapter 1.2.2.3 --- NRI/NRII as two-component system / Chapter 1.2.3 --- Post-translational regulation by adenylylation and deadenylylation --- p.11 / Chapter 1.2.3.1 --- Role of PII in adenylylation/deadenylylation / Chapter 1.2.4 --- Cumulative Feedback Inhibition --- p.15 / Chapter 1.3 --- PII in other bacteria --- p.15 / Chapter 1.4 --- PII in other higher organisms --- p.20 / Chapter 1.5 --- "PII protein is conserved in enteric bacteria, cyanobacteria, archaea, algae and higher plants" --- p.23 / Chapter 1.6 --- Nitrogen assimilation in higher plants --- p.25 / Chapter 1.6.1 --- Nitrogen uptake --- p.25 / Chapter 1.6.2 --- Primary nitrogen assimilation --- p.28 / Chapter 1.6.3 --- Nitrogen transport and interconversions --- p.28 / Chapter 1.6.4 --- Nitrogen flow --- p.29 / Chapter 1.6.5 --- Molecular regulation of nitrogen assimilation and possible roles of PII in plants --- p.30 / Chapter 1.7 --- Hypothesis of this study --- p.33 / Chapter 2. --- Materials and Methods --- p.35 / Chapter 2.1 --- Materials --- p.35 / Chapter 2.1.1 --- Plant materials --- p.35 / Chapter 2.1.2 --- Equipment and facilities used --- p.35 / Chapter 2.1.3 --- Growth media --- p.37 / Chapter 2.1.4 --- Buffers and solutions used in RNA extraction --- p.38 / Chapter 2.1.5 --- Buffers and solutions used in Northern blot analysis --- p.41 / Chapter 2.1.6 --- Molecular reagents and synthetic oligonucleotides used in the preparation of DIG-labeled probes --- p.45 / Chapter 2.1.7 --- Chemicals used in BioRad Protein Assay --- p.48 / Chapter 2.1.8 --- Chemicals and apparatus used in chlorophylls extraction and quantitation --- p.49 / Chapter 2.1.9 --- Buffers and solutions used in the glutamine synthetase enzyme extraction and assay --- p.49 / Chapter 2.2 --- Methods --- p.50 / Chapter 2.2.1 --- Plant growth --- p.50 / Chapter 2.2.2 --- RNA extraction --- p.52 / Chapter 2.2.3 --- Northern blot analysis --- p.54 / Chapter 2.2.4 --- Chlorophyll extraction and quantitation --- p.61 / Chapter 2.2.5 --- Root length measurement --- p.61 / Chapter 2.2.6 --- Total glutamine synthetase enzyme assay --- p.61 / Chapter 2.2.7 --- Measurement of total nitrogen in seeds --- p.64 / Chapter 2.2.8 --- Recording growth and development --- p.64 / Chapter 3. --- Results --- p.65 / Chapter 3.1 --- Overexpression ofPII and truncated PII mRNA in transgenic plants --- p.65 / Chapter 3.2 --- General growth characteristics of PII transgenic plants when grown on soil --- p.70 / Chapter 3.3 --- Physiological changes in the PII and truncated PII transgenic lines --- p.72 / Chapter 3.3.1 --- Fresh weight of the young seedlings --- p.73 / Chapter 3.3.2 --- Chlorophyll contents of shoots --- p.75 / Chapter 3.3.3 --- Root lengths --- p.88 / Chapter 3.3.4 --- Carbon and nitrogen status of seeds --- p.94 / Chapter 3.4 --- Expression of nitrogen assimilatory genes in PII and truncated PII transgenic lines --- p.96 / Chapter 3.4.1 --- Nitrate reductases --- p.96 / Chapter 3.4.2 --- Glutamine synthetases --- p.99 / Chapter 3.4.3 --- Asparagine synthetases --- p.107 / Chapter 3.5 --- Total glutamine synthetase enzyme activity --- p.117 / Chapter 4. --- Discussion --- p.126 / Chapter 4.1 --- Overexpressing PII and truncated PII in the transgenic plants --- p.126 / Chapter 4.2 --- The overall growth and development --- p.135 / Chapter 4.3 --- Chlorophyll --- p.135 / Chapter 4.4 --- Root length --- p.137 / Chapter 4.5 --- Expression of nitrogen assimilatory genes --- p.138 / Chapter 4.5.1 --- Genes encoding nitrate reductase --- p.138 / Chapter 4.5.2 --- Genes encoding glutamine synthetase --- p.140 / Chapter 4.5.3 --- Genes encoding asparagine synthetase --- p.141 / Chapter 4.6 --- Overall GS enzyme levels in the rosette leaves --- p.144 / Chapter 4.7 --- N/C ratio of the seed storage --- p.146 / Chapter 4.8 --- Proposed model for the roles of PII --- p.147 / Chapter 4.9 --- Conclusions --- p.149 / Chapter 4.10 --- Further studies --- p.150 / References --- p.152

Previous studies have shown that transcriptional differences in the orf224-atp6 mitochondrial gene region are correlated with fertility restoration of the pol CMS trait by the dominant nuclear Rfp gene in Brassica napus. Recently, the recessive rfp allele, or a tightly linked gene, was found to act as a dominant gene, designated Mmt, in controlling the production of additional, smaller transcripts of two other mitochondrial loci. The results presented in this thesis reveal that Mmt-specific transcripts lack sequences found at the $5 sp prime$ end of the full-length transcripts of these loci and contain a common sequence, UUGUGG, which maps immediately downstream of their $5 sp prime$ termini. A similar sequence, UUGUUG, is found within orf224 downstream of the major Rfp-specific $5 sp prime$ transcript terminus; these hexanucleotide sequences may serve as recognition motifs in the generation of Mmt- and Rfp-specific transcripts. These results suggest that Rfp/Mmt is a novel nuclear locus affecting the expression of multiple mitochondrial gene regions, with different alleles or haplotypes affecting different mitochondrial genes.

Regeneration and shoot multiplication of common bean (Phaseolus vulgaris L. 'ICA Pijao') from half-cotyledonary nodes was achieved on modified Murashige and Skoog (1962) basal medium amended with 5 $ mu$M 6-benzylaminopurine. Histological studies confirmed the adventitious origin of the regenerated buds. Shoots were rooted ex vitro and developed into morphologically normal plants compared with seed-grown controls. The relative susceptibility of bean tissues to infection by a collection of wild-type Agrobacterium strains was tested. Positive transformation events were evaluated based on morphological and biochemical changes observed following Agrobacterium infection. The A. tumefaciens strain C58 was particularly virulent on greenhouse-grown plants, in vitro-derived stem sections, half-cotyledonary nodes and seedlings. A sensitive and rapid method was developed to detect opines using thin layer chromatography. Transient $ beta$-glucuronidase (GUS) gene expression was detected in 'ICA Pijao' bean buds regenerated from half-cotyledonary nodes following Agrobacterium-mediated gene transfer with the binary vector pGV1040 or p35SGUSINT. Four out of eight putative transformants contained the chimeric GUSINT gene following polymerase chain reaction (PCR) analysis. This was confirmed by Southern analysis of blotted PCR gels. However, there was no stable integration of the GUSINT gene as none of the R1 progeny showed an amplified GUSINT fragment with PCR.

No description available.

Cold-acclimation-specific (CAS) gene expression was examined by screening a cDNA library prepared from poly(A)$ sp+$ RNA of cold-acclimated seedlings of a freezing-tolerant variety of alfalfa (Medicago falcata cv Anik). Three distinct CAS cDNA clones, pSM784, pSM2201, and pSM2358 were isolated. The genes corresponding to all three clones are coordinately induced by cold. Expression of these genes is not triggered by other stress treatments such as heat shock, water stress, wounding, or treatment with exogenous ABA. A positive correlation was observed between the level of expression of each gene and the degree of freezing tolerance of four alfalfa cultivars. / A full-length cDNA clone for the most abundantly-expressed gene, cas18 was isolated and sequenced. The deduced polypeptide, CAS18, is relatively small (167 amino acids), is highly hydrophillic, rich in glycine and threonine, and contains two distinctive repeat elements. It exhibits homology with members of the LEA/RAB/Dehydrin gene family--proteins which accumulate in response to water stress or abscisic acid (ABA). The cas18 cDNA hybridizes to three transcripts of 1.6, 1.4 and 1.0 kb in cold acclimated seedlings and cell cultures. The clone described here, Acs784, corresponds to the 1.0 kb transcript. / Expression of this gene is 30-fold greater in cold-acclimated cells than in nonacclimated cells after one week of low temperature treatment. Return to room temperature (deacclimation) results in the rapid disappearance of the three transcripts within just 5 hours. Studies of nuclear "run-on" transcription and transcript stability show that low temperature regulates the expression of cas18 at both the transcriptional and post-transcriptional levels.

Thesis (M.S.)--Oregon State University, 2008. / Printout. Accompanied by zipped folders that include Excel and pdf files. Includes bibliographical references. Also available on the World Wide Web.

Thesis (MSc Natural and Agricultural Sciences (Genetics))--University of Pretoria, 2007. / Includes summary. Includes bibliographical references. Available on the Internet via the World Wide Web.