Analysis Of Salt Tolerance In Transgenic Tobacco With LEA Gene From Tamarix.sp

The LEA gene was obtained from Tamarix.sp which is a drought resistance and salt tolerance plant. It was transformed into tobacco by Agrobacterium mediated genetic transformation.To analysis the function of LEA gene in order to cultivated resistance stress plants through genetic engineering means.The results it as follows:We selected 10 excellent lines to analysis from 41 buds was obtained.The PCR test showed the lines were positive in PCR.The results demonstrated that foreign target gene had been integrated into tobacco genome already.The result of real-time quantity PCR approved that the transformed gene can be expressed. However, there were differences among the 8 lines about expression level of LEA gene. The expression levels of LEA gene were 36.64¹69.32 times than that of GAPDH gene in the 8 lines.Study on 10 transgenic tobacco lines T₀ and control line with different salt concentration. The results showed: The transgenic tobacco lines T₀ can grow at the concentration of 230mmol/L.Research the average gain, the rooting efficiency and salt injury index after grow 20 days under salt stress condition. The results showed:The rooting rate of transgenic tobacco lines T₀ was 40⁶0%,but the controlwas 30%;The average gain of transgenic tobacco lines T₀ higher 45.58%⁷9.08% than control;The salt injury index of transgenic tobacco lines T₀ lower 37.6% than control, The T₀-17 was the lowest, it lower 60% than control. The 10 potted transgenic tobacco lines T₀ and control were used to research malondialdehyde (MDA) content and relative conductivity. The results showed: The salt tolerance of transgenic tobacco higher than control.Study on 7 transgenic tobacco lines T₀ and control line with different NaHCO₃ concentration. Research the rooting efficiency, alkali-injury, SOD activity, POD activity and relative conductivity. The results showed: The concentration of baking soda(NaHCO3) at 30mmol/L,the alkali-injury of transgenic tobaccos is 50%,the rooting rate is 10³0%, but the control line was damaged seriously and never rooted.The activity of SOD and POD have the maximum at the concentration. The result of relative conductivity showed the LEA gene could enhance the resistence of the tobacco to baking soda.Taking transgenic tobacco lines To transplanted in the greenhouse and obtained seeds(T₁).We growed them on culture medium of 1/2 MS at the Kanamycin concentration was 100 mg·L^-1.After 5 days, we count numbers of green plants and white plants. The results showed: The ratio of T₁-33, T₁-6 and T₁-22 was accord with (2²-1) : 1, the ratio of T₁-42 was accord with (2⁴-1) : 1.We selected 6 Ti lines to PCR test, all the lines were positive in PCR.The results demonstrated that foreign target gene still had been integrated into tobacco genome.The result of real-time quantity PCR approved that the transformed gene can be expressed. The expression level of LEA gene were 132.17²42.88 times than that of GAPDH gene in the 6 lines.Study on 6 transgenic tobacco lines Ti and control line with different salt concentration. Research the average gain, the rooting efficiency and salt injury index under salt stress condition. The results showed:the transgenic tobaccos rooted well at the NaCl concentration of 150mmol/L, weighed 7.72 times of the control, and were 3.51 times high of the control and the salt-injury index were 50% or lower. While the control hardly rooted and the salt-injury index were 65%. The above results proved that the transgenic first filial generation tobacco lines with LEA gene have the genetic stability, and the expression of LEA gene could enhance the resistence of the tobacco to salt and baking soda.