一种基于过敏性反应机制的抗植物病毒侵染策略

基于植物的过敏性反应机制，构建了PVY Nib基因和来自于细菌Bacillus amy—loliquefaciens的一类Rnase基因Barnase基因的融合基因的植物表达载体。在此表达载体内两基因的拼接处，保留了原来PVY蛋白酶识别PVYNIb和CP蛋白剪切位点的七肽保守序列。通过农杆菌介导获得此融台基因的转基因烟草植株。病毒侵染试验表明，转基因植物在病毒侵染后，发病症状被改变。少部分转融合基因的植株对病毒侵染表现局部抗性。

A New Strategy Derived from Plant Hypersensitivity Against the Infection of Potato Virus Y

In order to introduce an artificial hypersensitivity in plant , a binary plant expression vector carrying the fusion gene cassette of the nuclear inclusion b (NIb) gene from potato virus Y, Chinese isolate (PVY-C) and the barnase gene encoding one of the extracellular ribonucleases from Bacillus amyloliquefaciens has been constructed and transferred into tobacco. In the cassette, at the linkage site between the 3'termini of NIb gene and the 5' termini of barnase gene coding region, the heptapeptide consensus sequences , which is the special recognized cleavage site for PVY protease to process the Nib and coat protein translated from PVY genome, has been kept. The symptom caused by the infection of PVY-C in transgenic tobacco was found to be changed into yellow mosasaic and necrosis, which is different from the systematic mosaic infected by PVY-C in non-transgenic tobacco. Majority of the transgenic plants died of yellow mosaic and necrosis among 8-25 days of post-inoculation. Fortunately, three of total seventeen transgenic plants just show yellow mosaic and necrosis limited to the inoculated and the adjacent 1-2 non-inoculated leaves, the top 2 leaves have not been infected by virus. A possible hypothesis has been proposed to explain the phenomina.