赛葵黄脉病毒致病机制研究

【作者】 张弦；

【导师】 周雪平；

【作者基本信息】 浙江大学 ， 生物化学与分子生物学， 2004， 硕士

【摘要】 双生病毒是植物病毒中唯一的一类具有孪生颗粒形态的单链环状DNA病毒(single-stranded DNA，ssDNA)，双生病毒科病毒可侵染双子叶和单子叶植物，并在多种重要经济作物上造成严重的减产，在我国云南、广西、海南省的番茄、烟草、南瓜、胜红蓟和赛葵等植物上也相继发现了多种双生病毒。 对云南表现黄脉症状的赛葵杂草上的双生病毒分离物Y200进行了基因组结构研究。对其DNA-A基因组部分序列测定分析表明，该序列与赛葵黄脉病毒(MYVV)相应序列的同源性为96.1％。利用DNAβ的特异性引物，从Y200中扩增到卫星DNA分子。序列分析表明，该DNAβ全长1348个核苷酸，全序列与MYVV DNAβ的同源性最高，为96.1％。DNA-A部分序列和DNAβ全长序列分析表明，该病毒分离物为MYVV。 为了研究MYVV DNA-A和DNAβ在致病中的作用，我们构建了MYVV分离物Y47 DNA-A和DNAβ的侵染性克隆，侵染性测定表明MYVV-Y47 DNA-A单独可以侵染本氏烟、心叶烟和矮牵牛，但不能产生任何症状，只有与MYVV-Y47 DNAβ共同侵染时才能诱导产生黄脉、叶片卷曲的典型的病害症状。MYVV-Y47 DNAβ单独接种不能侵染植株。Southern印迹检测表明，MYVV-Y47 DNAβ依赖于辅助病毒进行复制，反过来DNAβ可以增强DNA-A在植物中的积累水平。因此，DNA-A与DNAβ之间是一种互作关系。更多还原

【Abstract】 Geminiviruses are characterized by their geminate virion particles and circular single-stranded DNA (ssDNA) genome. Geminiviruses infect both monocols and dicots and have caused significant losses in many economically important crops. In China, several kinds of begomoviruses were identified in tomato, tobacco, squash, ageratum and malvaslrum in Yunnan, Guangxi and Hainan provinces.Virus sample Y200 showing yellow vein symptom was collected form Malvastrwn coromandelianum in Yuanmou of Yunnan province. Partial DNA-A sequence of Y200 is most closely related to that of Malvastrwn yellow vein virus (MYVV) DNA-A with 96.1% sequence identity. DNAP molecule was amplified from Y200 with specific primers for DNAp, Y200 DNAp. contains 1348 nucleotides, it has 96.1% nucleotide sequence identity with MYVV DNAp. The partial DNA-A and complete DNAP sequences conform that Y200 is an isolate of MYVV.In order to investigate the role of MYVV DNA-A and DNAp in pathogenecity, infectious clones of DNA-A and DNAp of MYVV isolate Y47 (MYVV-Y47) were constructed. Infectivity assay show that MYVV-Y47 DNA-A alone could systemically infect Nicoliana benthamiana, N. glulinosa and Petunia hybrida plants without symptoms MYVV-Y47 DNAp is required for the induction of the typical symptoms including yellow cein, severe leaf curling, in these host plants. Southern blot analysis show that MYVV DNAp depends on the helper viruses for their replication and, in turn, is required for helper virus accumulation. Thus, MYVVDNA-A and DNAp are mutually dependent.更多还原