Application Of Biotechnology To Plant Material, Resistance To Cold Stress

With the development of economy, environment living beings depend on has had a huge change since Industrial Revolution. Heat island effect, greenhouse effect, environmental pollution, saline and alkaline desert, hunger soil and so on have a serious adverse impact on growth and development of corps, economic plants and vegetation. One of the important restrictive factors to interfere growth of plant is change of temperature. Gusty cold harm and freezing harm badly impede growth of many of economic plants especially of intertropical plants. Exploitation of novel botanical idioplasm materials by bioengineering technology not only has very important social significance, but also become a hot point of study of modern bioengineering technology and area of plant improving. Macroscopical ecological principle combines to the microcosmic genengineering technology have been a new area of research. Our study will improve the antistress hereditary characteristic of botanical materials by bioengineering technology including molecular cloning and gentransformation. And try to search after mechanism of gene expression-regulated to improve the ability against the cold stress, and solw the adverse effect of urban stress to distribution, growth and econimic benefit of plants.Many plants have an in-built ability to adapt the low temperture and drought, and this ability is cortroled by hereditary genotype of phylo evolution. In this study, a novel cold-regulate gene Cbcorl5b and its up-stream transcriptional activator Cbcbf and Cbcbf s up-stream transcriptional factor Cbice53 and a regultor of other cold-responsive gene CbLos2 have been cloned. All of these attested that there is CBF gene expression-regulated pathway and transcriptional cascade leading to the expression of cold-responsive genes under cold stress in Capsella bursa-pastoris, which ICE1 activate the expression of CBF by binding its promotor and CBF bind the DRE/CRT element in the promoter of the cold-regulated genes and activate transcription of them. Thereby increase piants' freezing tolerance. We also construct univalent vector of gene expression, which constitutive expression CamV35S activate theCor gene such as 1. P CamV35S-CbcorlSb cds-T Nos. At the same time, construct two kinds of vector, which CBF regulate the expression of cor suchas 2. P CamV35S- Cbcbf cds--T Nos , 3. P cold-induced promoter---CbcorlSb*cds--T Nos. And tranfer 1,3 and cotranfer 2,3 to the tobacco. In the futurewe could find out the offspring holding the increasing freezing tolerance and have a much better method to understand the freezing tolerance mechanism in plants.A novel cor gene was cloned from Capsella bursa-pastoris (designated CbcorlSb) (Genbank accession no. : AY437888) by RACE-PCR. The full-length cDNA of CbcorlSb was 652 bp and contained a 417 bp open reading frame (ORF) encoding a 139 amino acids hydrophilic protein. Multiple alignments showed that CbcorlSb had high similarity with other cold-regulated genes from Arabidopsis thaliana {cor 15b, corlSa), Brass!ca napus (bnllS, bnl9 and bn26) and late embryogenesis abundant (LEA) proteins. The predicted CbCOR15B protein was found to have a potential chloroplast signal sequence cleavage site, two cAMP-and cGMP-dependent protein kinase (PKA and PKG) phosphorylation sites. Cold acclimation assay showed that CbcorlSb was relevant to cold acclimation. All results presented implied that CbcorlSb might have similar functions possessed by other cor genes in increasing plants' freezing tolerance.A new CBF (Genbank accession no. : AY391121) gene was cloned from Capsella bursa-pastoris by rapid amplification of cDNA ends (RACE). The full-length ( nA of Capsella bursa-pastoris CBF gene {Cbcbf) was 1034 bp long and contained a 657 bp open reading frame (ORF) encoding a putative DRE/CRT (LTRE)-binding protein of 219 amino acids. The predicted CbCBF protein was found to have a potential nuclear localization sequence (NLS) in its N-terminal region followed by an AP2 DNA-binding motif and an acidic C-terminal half that might act as an acti...