Sleat D E, Palukaitis P
Department of Plant Pathology, Cornell University, Ithaca, NY 14853.
Plant J. 1992 Jan;2(1):43-9.
Some RNA plant viruses contain satellite RNAs which are dependent upon their associated virus for replication and encapsidation. Some cucumber mosaic virus satellite RNAs induce chlorosis on any of several host plants, including either tobacco or tomato. The exchange of sequence domains between cDNA clones of chlorosis-inducing and non-pathogenic satellite RNAs delimited the chlorosis domain for both tobacco and tomato plants to the same region. Site-directed mutagenesis of one nucleotide (149) within this domain changed the host plant specificity for a chlorotic response to satellite RNA infection from tomato to tobacco. Within the chlorosis domain, three conserved nucleotides are either deleted or altered in all satellite RNAs that do not induce chlorosis. Deletion of one of these nucleotides (153) did not affect satellite RNA replication but rendered it non-pathogenic. Thus, two single nucleotides have been identified which play central roles in those interactions between the virus, its satellite RNA and the host plant, and together result in a specific disease state.
一些RNA植物病毒含有卫星RNA，这些卫星RNA的复制和衣壳化依赖于与其相关的病毒。一些黄瓜花叶病毒卫星RNA会在包括烟草或番茄在内的几种寄主植物中的任何一种上诱导黄化。诱导黄化和无致病性的卫星RNA的cDNA克隆之间序列结构域的交换，将烟草和番茄植株的黄化结构域界定到同一区域。该结构域内一个核苷酸（149）的定点诱变改变了卫星RNA感染诱导黄化反应的寄主植物特异性，从番茄变为烟草。在黄化结构域内，所有不诱导黄化的卫星RNA中，三个保守核苷酸要么缺失要么改变。缺失其中一个核苷酸（153）不影响卫星RNA的复制，但使其无致病性。因此，已经鉴定出两个单核苷酸，它们在病毒、其卫星RNA和寄主植物之间的相互作用中起核心作用，并共同导致特定的病害状态。
