Research On Transgenic Tobacco Expressing Of Foreign Farnesyl Diphosphate Synthase Gene (FPS)

Farnesyl diphosphate synthase (fps) catalyzes two consecutivecondensations of isopentenyl diphosphate (IPP) with dimethylallyl diphosphate (DIMP) and the resultant geranyl diphosphate (GDP) to produce farnesyl diphosphate (FPP). Since FPP is the starting point of different branches of the pathway leading to the synthesis of large variety of isoprenoid end products, it is considered to play a key regulatory role of isoprenoid biosynthesis pathway. Previous reports suggesting that fps regulated the sesquiterpenes biosynthesis in plants are in line with this proposal. To investigate the contribution of FPS to plant disease resistance, fps gene of Mentha spicata was expressed in tobacco to observe its antifungal activity variation.The gene was cloned and inserted into binary vector under CaMV35S promoter to construct the plant constitutive expression vector pBinARfps. The leave discs of tobacco (Nicotinan tabacium L. cv. K326) were transformed with fps gene via Agrobacterium-mediated transformation. Shoots were regenerated on MS medium supplemented with 30mg/L Kan, 0.1mg/L IAA and 0.5mg/L BA and rooted on MS medium without hormone. PCR-Southern analysis proved foreign fps gene intergration in 5 Kanamycin resistance plantlets (K-4; K-6; K-17; K-19; K-35). Northern-blot indicated the foreign fps gene of transgenic plantlet had expressed at the transcriptional level. Disease challenge test of the detached leaves of transgenic plantlet by inoculation of Alternaria alternata and of the alive leaves of transgenic plantlet by inoculation of Phytophthora parasitica showed that the resistance was dramatically enhanced compared with non-transgenic plants. The result implicated the potential application of fps gene in plant disease-resistance engineering.According the theory of gene aparting, by Kan-ridding of the T1 individual plants' seeds, The T2 pure-plant lines were gotten ,and they were studied in the field. The pure-plant lines all grow well,and the colony orders well. The leaf shape,the leaf...