| By use of SSH (Suppression subtractive hybridization), a cold inducible expressing gene library was obtained from Dongxiang wild rice, which was considered to be the highest cold-tolerance rice in China. Some of the EST fragments from this library were found to be relative with the cold tolerance after they were sequenced. Three full-length cDNAs of choline kinase gene, glycine- and proline-rich protein and praline-rich extension-like receptor kinase were first isolated from indica rice. Characterizations and expression analysis of the three genes indicated that they were involved in cold-tolerance.Rice choline kinase gene encoded a predicted protein of 368 amino acids, sharing 74% similarity and 60% identity with choline kinase gene from Arabidopsis. There are two conserved motifs in the protein, The N-terminal presented in choline kinase of other plants and fungus, which maybe are not involved in the catalytic function. While the C-terminal of the choline kinase contained a phosphotransferase consensus sequence, which was presumed to be involved in catalytic function. A responsive element, DRE2 was found in the promoter region of the gene, which indicated that the choline kinase gene expression might be inducible by the dehydration. The expression analysis also showed that the gene expression level increased under the cold condition.The glycine- and praline- rich protein (GPRP) gene coding 197 amino acids was cloned in indica rice. Five kinds of amino acids-glycine, proline, histidine, alanine, tyrosine and lysine accounted for 79% of the total compositions. The analysis of the composition of amino acid, molecule weigh, isoelectric point and phylogenetic tree showed that the GPRP from rice was highly homology with the GPRP from Sporobolus stapfianus, which had been found to be inducible by the dehydration. There were a dehydration responsive element, DRE2 and two WRKY1 boxes, which was involved in adjusting the early-stage defense response. The expressing analysis also showed that the gene expressing level increased under the cold condition.The full-length cDNA of PERK gene encoding a predicted protein of 682amino acidswas, was first isolated from indica rice. Based on the overall structure, PERK was predicted to encode a novel receptor-like kinase with three distinct domains: an extracellular domain, a single membrane-spanning domain, and a kinase domain. The N-termial region contained four extension pentapeptide signature motifs, (Ser-Pro)4. In the promoter region, there was one EMBP1A.01 element involved in mediating ABA-responses and one WRKY.01 element associated with pathogen defense.The other three partial sequences of malic enzyme, 3-phosphoglycerate kinase, and an unknown function gene were obtained from the Dongxiang wild rice. Compared with the genome of the indica and japanica, the genes from Dongxiang wild rice were conservative, 'most of the differences were in the un-coding region. While there were many mutations in their coding regions. For most of the mutations, Dongxiang wild rice had the same base pair with indica but was different with the japanica, indicating that the Dongxiang wild ricewas much similar with the japanica. The mutation pattern in gene level among the three rice supported the theory that indica and japanica evolved respectively.A novel osClpD gene, encoding a highly conservative ClpD subfamily member, was first isolated and characterized from Oryza sativa. The full-length cDNA of osClpD gene was 3140bp and contained a 2884bp open reading frame encoding a 938 amino acid protein. The phylogenetic tree and blast search showed that OSClpD belonged to the ClpD subfamily of the Hsp100/Clp family, and contained all protein motifs characteristic for the ClpD subfamily of Hsp100/Clp proteins. The real-time quantitative PCR analysis proved that it was inducible by water deficit and temperature stress in vegetative tissues.
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