Studies On Antisense Gene Transformation And Expression Of Key Genes Related To Tea Quality In Tea Plant

The Camellia sinensis (L.)0 Kuntze is one of the major cash crops, and the Tea industry takes an important place in agriculture industries in China. The current market demand of tea products is changing and the traditional breeding can't meet the demands of tea production because the cycle of the traditional breeding takes decades of identification period. With the development and mature of biochemistry and transformation technologies, plant gene engineering can be used in directional genetic breeding of tea plant [Camellia sinensis(L.)O Kuntze].The Caffeine is a cordial with stimulating effect. It will induce heart-throb, anxiety, trembling, high blood pressure, insomnia and etc if it is intaken excessively. With the improvement of living conditions, people pay more and more attention to the health. Lower caffeine tea products are fixed people's eyes on. We used the method of plant transformation technology i.e. antisense gene technology, to control the key enzyme of caffeine synthesis pathway so as to attain new tea gerplasms.The results showed that S-adenosylmethionine synthase(SAM) gene and caffeine synthase(TCS) gene were the key genes in caffeine synthesis pathway, which take important roles in the caffeine biosynthesis. In the present research, the recombinant vector expressing antisense DNA of SAM (pCAMBIA1301-antiSAMS) has been constructed. Fragments of the first exon of the SAM gene were amplified by RT-PCR, then inserted in reverse order into plasmid pCambial301. After triparent mating, the pCAMBIA1301-antiSAMS vector was transformed into Agrobacterium rhizogenes . Transformation conditions including bacterial strains, co-culture media, explants of tea plant, PVP treatments have been investigated and optimized as YMB co-cultured media, without PVP pre-culture, 60-70days stem . The hairy root was got and through GUS dying, the pCAMBIA1301 -antiSAMS vector has been transformed into the hairy root successfully.Investigation in response of TCS gene and SAM gene to fiuence dosages and durations of UV-B showed that expression of the two key genes were not induced by...