The Modification Of Fatty Acids Composition In Peanut Using Gene-silencing Technology

Peanut is one of the main economic crops and its quality improving is meaningful toproduction practice. When applying traditional breeding techonlogy, there exist manyproblems such as high randomicity, long breeding cycle and limitation to improve specialconstituents. Therefore, agriculture traits are difficult to be valued. With the developmentof gene engineering, it has become an effective avenue to improve crop traits, shorten thebreeding cycle and increase the efficiency. So many researchers aim at to modify farry acidcompositions of peanut via transgenetic technology.Oleic acid is a monounsaturated fatty acid and very stable. It can decrease harmfulcholesterol (low density lipoprotein) and maintain the useful cholesterol (high densitylipoprotein), then postpone atherosclerosis and prevent cardiovascular disease attacking.Therefore it is very important to improve the oleic acid content, increase the ratio of oleicand linoleic acids and oxidation stabilization in peanut seeds. The purpose of this study isto silence the expression of an important fatty acid dehydrogenase gene, which encodingoleylphosphatidylcholine ω-6 dehydrogenase, in order to improve the oleic acid contentand peanut fatty acid composition. The results were obtained in this study as follows:1. Construction of the special transforming vector pPNHO-3. According to the publicahFAD2B gene sequence in Gene Bank, we designed the specific primers. Theamplified PCR products were ligated into the intermediate vector forward or backwardwhich including a part of intron sequence, made an inverted repeats seqeunce. Thewhole intermediate vector with inverted repeats was inserted into the plasmid includingpromoter and terminator genes of soybean lectin, formed a vector named pPNHO-3.2. Modification the genetic transforming system of ahFAD2B mediated byAgrobacterium. Researches showed that 2mg/LVc used in media could preventexplants browning effectively. 125mg/L kanamycin is the appropriate screeningpressure.3. Testing the T0 and T1 transformed strains through PCR indicated that the targetfragment integrated into the plant genome. The primary results showed that 11 of 37strains were positve, and 4 hanve fructified and the oleic content were being tested.4. Optimized and improved some technology of peanut transforming, such as antibioticselecting, preventing browning and genotype identified. Also the paper put forwardsome practical suggestions about boosting transforming efficiency.