| Cottonseed is the by-product of cotton, it can be used to produced cottonseed oil, but not effect the production of fiber. Cottonseed oil is a major source of edible vegetable oil for human in the worldwide, and it can also be used as industrial materials. Cottonseed oil contains large amount of essential fatty acids, among which the content of linoleic acid is the highest. Linoleic acid can inhibit cholesterol in the blood. Besides, there are lots of palmitic acid, stearic acid, oleic acid and arachidic acid in the cottonseed oil. The human body on cottonseed oil digestibility is 98%. In the industrial, cottonseed oil can be used to produce soap, glycerin, ink, solvent oil and pesticide. Cottonseed oil has an important role in solving the food, health and environmental issues. Therefore, it has significant meaning to raise oil content of cottonseed.Phosphoenolpyruvate carboxylase (PEPC) is closely related to plant oil content. It controls indirectly the direction of the flow of pyroracemic acid, which is the common substrate of protein and lipid biosynthesis and determines the ratio of the protein/lipid content of plant seed. We construct ihpRNA expression vector of PEPC, make solubility sugar be so as to flow into metabolic pathway on fatty acid, and improve the content of oil in cottonseed. We have the following achievements:1. The PEPC gene fragment andαglobulin B gene promoter were isolated from Gossypium barbadense by PCR methods. The results show that the two sequences share a homology of 99% and 97% respectively with the sequence reported. We use the two promoters respectively with PEPC fragment to construct ihpRNA expression vector. Then, the two seed-specific ihpRNA expression vectors PCADSNPSPA and PCADSBPSPA were verified by PCR and restriction endonuclease. Then the two vectors were transformed to Agrobacterium strains LBA4404 and identified by PCR.2. The stems of cotton and the leaves of tobacco were dipped into the Agrobacterium strains LBA4404 with PCADSNPSPA and PCADSBPSPA respectively. Through the results of the research, we found that in the control group, the plants were well-grown, on the other hand, the growth of plants in the experimental group were inhibited. The reason may be that PEPC has important function in the development of plants, so if the function of PEPC was inhibited, the metabolize was undoubtedly be affected. Another reason is we interferenced the gene which share high homology with PEPC, or a gene family was interferenced.3. In the present study, PEPC gene analogues from 16 species in Gossypium were obtained by PCR strategy using specific primers designed from the ORF of GhPEPC1(GenBank Accession: AF008939). Homologous sequences of PEPC comparison indicated that the differences between the genes at nucleotide and amino acid levels were 0.3% to 9.8% and 0.2% to 18.8% respectively, except G.longicalyxPEPC1. The neighbor-joining (NJ) and minimum-evolutin (ME) trees showed that the results were consistent with Gossypium classification previously reported by Fryxell. Allotetraploid cotton species might origin from G.herbaceum and G.thurberi; this research elucidated the relationship among Gossypium species at nucleotide level, which could proved some help for the utilization of plant germplasms.
|
PDF Full Text Request