雪花莲凝集素基因（gna）的改造及其抗蚜性

用定点突变方法对编码雪花莲凝集素（Galanthus nivalis agglutinin,GNA)前体蛋白的DNA序列进行了改造和转基因烟草9Nicotana tabacum L.）抗蚜性的研究。结果表明，将GNA编码序列中含有的稀有密码子改造后，GNA的表达水平从占总可溶性蛋白的0.17％增加到0.25％，转基因烟草的抗蚜性也随之增强，从平均抑制桃蚜（Myzus per-sicae(Sulzer））虫口密度63.7％显地提高到71.0％。

Aphid-resistant Transgenic Tobacco Plants Expressing Modified gna Gene

A gene sequence coding for the precursor of Galanthus nivalis agglutinin (GNA) was modified by site_directed mutagenesis to change very low usage bias codons to higher usage bias ones for improvement of the gene expression in transgenic tobacco (Nicotiana tabacum L.) plants. Results from Western blot analysis of some of the transgenic tobacco plants showed that the expression level of GNA in plants transformed with the modified gene GNA34m reached 0.25% of total soluble proteins, while that of the GNA34 gene transgenic plants was 0.17%. Since the GNA expression level increased, the aphid resistance of GNA34m transgenic plants were also enhanced significantly as judged by a 71.0% aphid population inhibition in insect bioassay of GNA34m transformed plants and 63.7% for the plants transformed with the natural GNA34 gene.