CP基因遗传转化甘蔗品种Badila与福农91-4621的抗病性差异分析

Difference of coat protein mediated resistance to sugarcane mosaic virus between Badila and Funong 91-4621

利用含甘蔗花叶病病毒E株系外壳蛋白基因(CP)的质粒pUbi-SCMV-CP,用基因枪轰击法遗传转化不同甘蔗品种,所获得的转基因无性系经过3代的抗病性鉴定和H2O2代谢的分析.结果表明,Badila(TB1)转基因植株具有较强的抗花叶病能力,而福农91-4621在转基因无性系T1、T2中表现出较强的抗病性,但在T3中其抗病性开始退化,发病率高达68%;抗病生理分析表明,转基因无性系的抗病性与H2O2清除和积累有关.经RT-PCR克隆和测序分析,福农91-4621所感染的SrMV-H的CP基因氨基酸序列与转化的SCMV-E的同源性较低,仅为73.2%,福建Badila所感染的是SCMV-D,与SCMV-E同源性高达97.8%.说明CP基因对本身所来源的病毒或是与原病毒亲缘关系较近的病毒可能具有较强的抗性,而对同属于SCMV的其他病毒虽有抗性,但抗性较弱,且随着转基因世代数的增加而降低.

Coat protein （CP） gene from SCMV-E strain in the expression vector of pUbi-SCMV-CP was transformed to different cultivars （ cv, Badila and Funong 91-4621 ） of sugarcane via bomboardment. The incidence of three generations in the field and H2O2 metabolisms in the second generation of the transgenic clones （TB1 from Badila and TF1 from Funong 91-4621 ） were investigated after inoculation with SCMV. It was showed that transgenic clone of TB1 from Badila was highly resistant to SCMV with lower incidence percentage; and same transgenic TF1 from Funong 91-4621 was also highly resistant to SCMV in the first and second generation with lower incidence percentage, but its incidence percentage was 68% in the third generation. After sequence comparison of CP, it was showed that Funong 91-4621 was most closely related to the isolate from USA, SrMV-H, and had the identities of 73.2% with SCMV-E. And Fujian Badila had high identities with SCMV-E （the identities of 97.8% ）. The result indicated that virus resistance obtained in transgenic plants was usually virus-specific, infected the plants with other viruses or other strain viruses could reduce levels of resistance.