| Flower color is an important one of qualitative charac ers and economic barometers for the ornamental plants. Because of the colors for many focal flowers are limited, for example, the roses, carnations, tulips and so on, which flowers are lack of the color for blue and violet. And the reforms for the ornamental plants colors are provided with the advantages such as the visual arts, and the large economic potential. Gene engineering technology is more superior than the Cross breeding and Directive breeding technology with its short cycle , low cost and high benefit. Though traditional breeding technology has been used for a long time. Now the direct reports for the changes of the flower color by the CHI (Chalcone Isomerase ) gene are a few what we known.. In this dissertation, the author cloned the CHI gene from Saussurea medusa Maxim by RT-PCR, and constructed the CHI gene sense and antisense plant expressional vector pBinCHI+ and pBLCHI., respectively. Sense and antisense CHI gene were transformed , respectively into Petunia hybrida Vilm. with the pure deep red ; and sense CHI gene was transformed into pure white, all mediated by Agrobacterium tumefaciens. We study the changes of the flower color by the co-suppression , anti-suppression of the CHI gene and CHI gene overexpression. Moreover, we observed the variations of the flower organs from the Petunia hybrida Vilm which color been transformed. The main experiment and results of this paper are such as follows: 1. Cloning and sequence analysis of CHI gene fragment from Saussurea medusa Maxim.The CHI gene fragment was amplified by means of RT-PCR, using flower mRNA of Saussurea medusa Maxim, as template, and a pair of specific oligonucleotides (according to the CHI gene sequence, AF509335) as primer, and cloned into pUCm-T vector with TA connection. The vector was named pUCm-CHI. Results showed that the CHI gene fragment sequence consisted 810bp, and Open Reading Frame(ORF) is 699bp. The putative protein includes 232 amino acids, and it's MW is 24913 D, PI 4.75.The ORF sequence is the same as the ORF of AF509335.2. Construction of plant expressional vector of sense and antisense CHI genepUCm-cHI and pTripiEx2 digested with EcoR I and Sal I was constructed for mediated vector pTripCHI in which has correct direction.p TripCHI and pBinAR digested with KpnI and XbaI wasconstructed for plant expressional vector pBinCHI+ of sense CHI gene, pTripCHI and pBL19 digested with Kpni and Xbal was constructed for plant expressional vector pBLCHI- of antisense CHI gene. pBinCHI+ and pBLCHI- were transffered into EHA105 and LBA4404, respectively.3. Introduction of CHI gene into Petunia mediated by Agrobacterium tumefaciensYoung leaves of were excised from sterile seedlings of pure deep red petunia, cut into 5×5mm2, dipped into Agrobaterium (OD600 adjusted to 0.2) for 15min. Patted dry on the filter paper, transferred to MS3 medium and co-cultured for 3-4 days in darkness. After co-cultivation, all the explants were washed in liquid MSO medium containing 500mg/L Cef for 2 hours. Washed with sterile water for 5 times and patted dry on the filter paper again. Subsequently, the explants were transferred to MS1 medium supplemented with 200mg/L Cef for 3-6 days delay selection and then transferred to MS1 medium supplemented with 200mg/L Cef and 50mg/L Km for selection culture. The resistant shoots were rooted on 1/2 strength medium containing 10mg/L Km and then transferred the plantlets with normal roots to field for further analysis. MSI was replaced by MS2 in pure white petunia at delay selection and antibiotic selection. pBinCHI- and pBLCHI- were transformed into pure deep red petunia, and the transforned plants were named RCHI+and RCHI-, respectively. The pure white transformed by pBinCHI+ was named WCHI+. Untransformed pure deep red petunia is control R0; Untransformed pure white petunia is control W0. Statistic results showed that the resistant shoots RCHI+ has 28 lines; R CHI-has 18 lines and WCHI+ has 15 lines.4.The identification of transfo...
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