转抗蚜GNA基因苜蓿的研究

Studies on transgenic Medicago truncatula expressing GNA gene

将雪花莲凝集素基因GNA插入双元载体pBI121中的GUS基因的上游,得到植物表达载体pLG66m。GNA与GUS基因构成融合基因,共用一个CaMV35S启动子。将该表达载体导入农杆菌LBA4404,得到LBA4404／pLG66m菌株。利用LBA4404／pLG66m菌株培养液直接浸泡萌动的苜蓿种子,组织学检测表明GUS在种苗上3 d的瞬时表达效率超过90％。待苜蓿长出第3片真叶后检测,GUS表达效率明显下降。GNA基因在种苗期间的短期表达也积累GNA毒蛋白在苜蓿体内的含量,为苜蓿在苗期抗蚜起到一定作用。

The gene of Galanthus nivalis agglutinin was inserted to the upstream of GUS gene via binary vector pBI121, resulting in one plant expression vector pLG66m. In the vector, GNA gene and GUS gene were transcribed together by CaMV35s promoter. The strain LBA4404/pLG66m was produced by introducing the vector pLG66m into Agrobdcterium tumefaciens LBA4404. The sprouting seeds of alfalfa were soaked directly in this strain for transformation. The instantaneous expressing efficiency of GUS gene in young treated seedlings was more than 90%. The expression dropped signifi canlty when the third real leaves outgrew. However, it is too early to tell whether the transgenes can be inherited stabely and express GUS gene instantaneously or not. Expression of GUS gene in plants could be inspected by histological method, which proves that foreign genes can enter plant cell nucleus and express efficiently by making use of this simple method. Besides, the toxipeptone constantly accumulated in plants during expression of foreign genes, which may play an important role at the initial stage of seedling.