[目的]快速鉴定运动蛋白基因在烟草中的瞬时表达,进一步研究该外源基因的功能。[方法]将大麦黄矮病毒的运动蛋白基因定向克隆到马铃薯X病毒载体上,得到重组的马铃薯X病毒,电击转化农杆菌后,利用农杆菌渗透注射技术注射到本生烟草的叶片中,逐日跟踪观察病毒对烟草的侵染状况。[结果]重组的PVX病毒载体进行PCR鉴定和双酶切鉴定(BamHI+XhoI),均得到了462bp的基因片段,证明外源片段BYDV-MP确实克隆到了PVX病毒载体GR107上。将含有重组的PVX病毒载体GR107-MP和空的PVX病毒载体GR107的农杆菌渗透缓冲液注射到5~6叶期的烟草幼苗后,第7天观察,重组病毒载体侵染的烟草系统叶有病毒侵染症状,而对照组未有此现象。对2组实验进行逐日跟踪观察,重组病毒载体侵染的烟草有较严重的病毒侵染症状和叶片卷曲现象,后期引起注射叶及系统叶坏死。而空病毒载体侵染的烟草只有轻微的病毒侵染症状,并能够恢复健康。对侵染的烟草进行RT-PCR检测,结果表明外源基因BYDV-MP在烟草体内进行了正常的转录和表达。[结论]BYDV-MP蛋白促进了PVX的系统侵染速度,加重了系统侵染的病毒症状,是病毒病症的决定因子;利用PVX表达载体表达异源MP的方法是可行的。
[Objective]The aim of this study was to identify transient expression of movement protein (MP) gene in Nicotinana benthaminana rapidly and further investigate the function of this exogenous gene. [Method]The movement protein gene of barley yellow dwarf virus (BYDV) was cloned into potato virus X (PVX) viral vector of pGR107,and PVX-recombinant vector was obtained. After electroporation of Agrobacterium tumefaciens,PVX was inoculated into the lower leaves of tobacco by Agrobacterium infiltration assay to observe the infection of virus on tobacco. [Result]After infection for 7 days,upper non-inoculated leaves of tobacco infected by the PVX-recombinant vector showed the virus infection symptoms,while the control group had no viral infection phenomenon. Daily follow-up observations for two groups revealed that tobacco infected by PVX-recombinant vector had severe symptoms of virus infection and curling leaves,or even led to necrosis both in infiltrated and systemic leaves in late period. However,tobacco infected by PVX vector had only slight symptoms of virus infection and could recover from infection. RT-PCR of the infected tobacco indicated that exogenous gene BYDV-MP had a normal transcription and expression in tobacco. [Conclusion]As a determinant factor for viral disease,BYDV-MP promotes the systemic infection rate of PVX and its symptom. In addition,it is feasible to express exogenous MP gene in Nicotiana benthaminan via PVX expression vector.