Zhang L, Handa K, Palukaitis P
Department of Plant Pathology, Cornell University, Ithaca, New York 14853.
J Gen Virol. 1994 Nov;75 ( Pt 11):3185-91. doi: 10.1099/0022-1317-75-11-3185.
Cucumber mosaic cucumovirus (CMV) can be divided into two subgroups, I and II. LS-CMV and most other subgroup II strains cause a mild, systemic mottle on tobacco and can induce a necrotic etching (necrotic rings) symptom on inoculated tobacco leaves. In contrast, Fny-CMV and most other subgroup I strains cause severe, systemic mosaic symptoms on tobacco, but do not induce the necrotic etching symptom. Full-length cDNA clones of all three genomic RNAs of LS-CMV were constructed and infectious RNAs were generated from these clones. Using pseudorecombinants constructed from the infectious transcripts of LS-CMV and Fny-CMV, we found that both RNAs 1 and 2 of Fny-CMV are involved in determining the severity of systemic symptom on tobacco, and that LS-CMV RNA 3 contains the determinant for the necrotic etching symptom. Chimeras formed between Fny- and LS-CMV RNA 3 were used to demonstrate that the inducer of the necrotic etching symptoms mapped to the 5' 618 nucleotides of LS-CMV RNA 3, and required sequences in both the 5' non-translated region, as well as the 3a gene of CMV.
黄瓜花叶黄瓜病毒（CMV）可分为两个亚组，即亚组I和亚组II。LS-CMV及大多数其他亚组II毒株会在烟草上引起轻度的系统性斑驳，并能在接种的烟草叶片上诱导坏死蚀纹（坏死环）症状。相比之下，Fny-CMV及大多数其他亚组I毒株会在烟草上引起严重的系统性花叶症状，但不会诱导坏死蚀纹症状。构建了LS-CMV所有三个基因组RNA的全长cDNA克隆，并从这些克隆中产生了感染性RNA。利用由LS-CMV和Fny-CMV的感染性转录本构建的假重组体，我们发现Fny-CMV的RNA 1和RNA 2都参与决定烟草系统性症状的严重程度，并且LS-CMV RNA 3包含坏死蚀纹症状的决定因素。Fny-CMV和LS-CMV RNA 3之间形成的嵌合体用于证明坏死蚀纹症状的诱导因子定位于LS-CMV RNA 3的5'端618个核苷酸，并且需要CMV 5'非翻译区以及3a基因中的序列。
