Genetic Transformation Of Sweetpotato And Changes Of Some Characters In Transgenic Plant

Sweetpotato [Jpornoea hatatas (L.) Lam.] is an important food and material crop, hut the content of protein in it is seldom and the composition of amino acid isn balance L\sine and methionine are essential amino acids for human, they are Iackini~ in sweetpotato Since 1980? improvement in quality has become the most important target in sweetpotato breeding, and improvemeiit in content and composition of protein has become one of main targets n quality breeding of sweetpotato both in China and abroad. In this paper. superior cultivars of sweetpotato vere used as test material. To improve the frequency of genetic transformation, to obtain transgenic plants in different cultivars and to explore expression of foreiun genes and the effect of integrative of foreign genes on expression of inside genes. fast reproduction of sterile cuttings, the genetic transformation by Agrohtwlcriiirn-mediated. and changes of some characters in transgenic plant were studied in this paper. The results from audio-visual analysis and variance analysis shoved that liquid culture could improve growth and was suitable for fast reproduction of sterile cuttings. The etTect of the liquid culture for 20 days on number of leaves of each plant, area of each leaf and length of petiole wasn significant. The effect of the liquid culture tir 60 days on number of leaves of each plant was significant; and on area of each leaf, length of petiole, number of buds of each plant wasn significant. The results also suggested that the effect of the liquid culture on height of plant of sterile cuttings had genotype dependence. Based on the iii iWo genetic transformation system in sveetpotato. established by Feng Gao.the protocol in this paper was adopted as following: the stem explants were pre-cultured for 5 days, immersed in the bacterium solution (0D6000.3) for a few minutes, co-cultured in light condition for 3 days, and then cultured in the postponed medium for 5 days. Finally, the transgenic plantlets were regenerated on the selected medium. The medium of MS + 1.0 mg/L NAA could be used as basic medium during the procedure. In this paper, based on the above-mentioned genetic transformation protocol, the stem explants of many superior cultivars of sweetpotato and LBA4404/pSP I OZ strain of Agrobacieriumn tumefaciens were used as test material. The effect of many factors, such as infection time, genotype of sweetpotato, acetosyringone(AS), pH of co-culture medium, proline and so on, on the in vitro genetic transformation in sweetpotato had been studied. The results demonstrated that infection time had a great effect on survival and differentiation of explants. Infection time was too short; bacterium, which stuck to explants, weren enough. This was disadvantageous to genetic transformations. Infection time was too long: bacterium reproduced too much, and they could make the explants die. Under the conditions of this test, the suitable time for A. tumefaciens infecting stem explants of sweetpotato was 1015 minutes. The results showed that AS could heighten the percentage of transformation; and its effect was related to pH; lower pH was beneficial for the transformation. Explants infected by bacterium solution supplemented AS in culture were obtained Kanr buds after they were cultured for a mouth in the selected medium; .and the percentage of obtaining was 2.63%. Explants infected by bacterium solution without AS in culture weren obtained Kanr buds afLx they were cultured for a mouth in the selected medium. Explants cultured in co-culture medium added AS were obtained Kanr buds: and th...