黄瓜绿斑驳花叶病毒北京和山东分离物的生物学测定及其基因组比较

Bioassay and genomic studies on the two isolates of Cucumber green mottle mosaic virus from Beijing and Shandong.

为揭示黄瓜绿斑驳花叶病毒的分子流行学特征,通过RT-PCR和cDNA克隆技术获得并分析了从北京甜瓜和山东西瓜上分离的2个黄瓜绿斑驳花叶病毒(CGMMV)分离物CGMMV-Beijing和CGM-MV-Shandong的全序列。结果表明CGMMV-Beijing和CGMMV-Shandong的基因组分别由6423和6427个核苷酸组成,包括5′及3′端非编码区和4个开放性的阅读框,分别编码129kDa和186kDa复制相关蛋白、29kDa的移动蛋白及17.4kDa的外壳蛋白。寄主范围测定显示在供试的6科11种植物中CGMMV-Beijing和CGMMV-Shandong均可侵染葫芦科的葫芦、南瓜和西瓜以及茄科的本氏烟和藜科的苋色藜,不侵染供试的其它植物。CGMMV-Beijing和CGMMV-Shandong基因组的核苷酸同源性为99.5%,186kDa蛋白的核酸和氨基酸同源性分别为99.7%和99.8%,移动蛋白的核酸和氨基酸同源性分别为99.3%和98.1%,外壳蛋白的核苷酸同源性为100%。多序列比对分析结果显示,CGMMV的各分离物之间的分子差异并不明显,核苷酸同源性均在98%以上。将CGMMV-Beijing和CGMMV-Shandong与侵染葫芦科植物的烟草花叶病毒属其它成员比较,结果显示其亲缘关系较远,基因组的核苷酸同源性介于56.7%～59.6%,外壳蛋白的氨基酸同源性在44.7%～54.0%之间。综合分析显示,CGMMV分离物之间的差异并不明显,可能具有共同的侵染来源。

To reveal the molecular epidemiological character of CGMMV, two complete nucleotide sequences of genomic RNA of CGMMV-Beijing and CGMMV-Shandong isolates were determined by sequencing 5 overlapping viral cDNA clones generated by RT - PCR, which are 6423 and 6427 nucleotides, respectively. Both of the two i- solates were consisted of 5＇UTR ,3＇UTR and four ORFs corresponding to 129kDa and 186kDa of replication -as- sociated proteins, 29kDa of movement protein and 17.4kDa of coat protein. Host range analysis showed that among the 6 families 11 kinds of host plants included, CGMMV - Beijing and CGMMV - Shandong could infect Cu- curbita pepo,Cucuribita moschata,Citrullus lanatus,Nicotiana benthamiana as well as Chenopodium amaranticola, not infect other test plants. The genome of the nucleotide sequences of the two isolates were 99.5% in homology. The nucleotide and amino acids sequences of the 186kDa replicase of CGMMV-Beijing and CGMMV-Shandong were 99.7% and 99.8% in homology, respectively, while that of movement protein were 99.3% and 98.9%. The coat protein sequence were absolutely identical. Multiple sequences alignment comparing to other CGMMV isolates showed that the nucleotide identities were more than 98% ,but that with other cucurbit -infecting tobamoviruses were ranging from 56.7% to 59.6% ,while the homology of the amino acids of the coat protein were between 44.7% and 54.0%. The results above suggested that no remarkable diversity was found among the CGMMV isolations and they might share the same infection source.