| Brassica napus is an important oil crops in our country. Rapeseed provides not only edible vegetable oil and proteins, but also ideal raw material for biodiesel. With the rapid development of plant genetic engineering technology, transformation technology has been successfully used to improve rapeseed production, quality and stress resistance. Currently agrobacterium-mediated transformation is one of the most commonly used, which have the highest transformation efficiency among methods used for genetic transformation in rapeseed.However, the differentiation and regeneration system in rapeseed has a strong dependence on the genotype, the transformation efficiency of most genotypes are low, and the reproducibility of existing transformation procedures is poor. Therefore, the selection of suitable materials as transformation donors, and the establishment of an efficient transformation system has been the hot issue in transformation studies.In this experiment the following aspects were carried out and the mojor results are presented as follows.1. On the basis of the previous work in our laboratory, an antisense FAD2 driven by Napin promoter (pNapin:aFAD2) was introduced into four genotypes (westar、jiaA049、jia572、jiaA102) and the transformation efficiency between these genotypes analyzed. We identified that the line jia572 has the highest transformation efficiency among the four genotypes. The shoot regeneration rate was up to 46.73%, and the transformation rate was up to 40.67%.2. Through the determination of fatty acids in plant seeds in the positive To generation and T1 generation, we concluded that the oleic acid content of the 11 individual transformants exceed the wild type plants out of 18 To generation transgenetic plants, and the oleic acid content are more than 70% in 5 plants. The average oleic content in five T1 lines ranged 68-79%. Among 29 T1 transgenetic plants, there were 4 plants with over 80% and the highest content of C 18:1 in individuals of transgenetic was up to 83%. So, the oleic acid content in transgenic plants was much higher than 64% in the wild type plants. The oleic acid content increased, while linolic acid and linolenic acid content decreased accordingly. The results showed that the expression of the antisense construct fad2 inhibited conversion of oleic acid to linolic acid and linolenic acid. 3. We transformed the rapeseed with two BnLAS gene constructs MG12G-4 (pBnLAS: BnLAS) and vp-5B (35S:BnLAS), which contain different promoters, and get positive plants. We observed that the phenotypes of vp-5B transformed plants were changed significantly including increased lateral branches. |
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