根癌农杆菌介导的苜蓿体胚转化

以苜蓿体细胞胚胎作为根癌农杆菌介导转化的受体，通过对GUS基因瞬时表达率的分析，研究该转化体系的最佳实验参数。实验结果显示，负压处理10min和共培养5d时表达率最高(可达17．4％)。以这一转化方法分别对带有3种不同启动于的表达载体进行比较，发现由CMV35S启动于驱动的GUS基因的瞬时表达率可达82．7％，Ubil启动于驱动的可达57．8％，而Actl启动于驱动的则未见表达。

Transformation of Alfalfa (Medicago sativa L.) Somatic Embryos Mediated by Agrobacterium tumefaciens

Using transient expression of GUS gene, the optimal conditions for Agrobacterium-mediated transformation of alfalfa somatic embryos was investigated. Histochemical GUS assay showed that the transient expression rate was increased by negative pressure treatment and longer co-culture duration(Figs.3, 4). The highest level of transient expression was obtained by 10 min of negative pressure treatment and 5 d-coculture. To study the effect of promoters on transformation, three expression vectors with GUS gene under respective control of CaMV35S, wheat Ubiquitin 1 promoter and rice Actin 1 promoter were tested with the optimum transformation method. A transient expression rate as high as 82.7% generated by CaMV35S promoter had been obtained, while a transient expression rate of 57.8% had been generated by Ubi1 promoter, and no expression had been shown by Act1 promoter (Table 1).