Knorr D A, Mullin R H, Hearne P Q, Morris T J
Department of Plant Pathology, University of California, Berkeley 94720.
Virology. 1991 Mar;181(1):193-202. doi: 10.1016/0042-6822(91)90484-s.
Defective interfering (DI) RNAs were generated de novo in each of 12 independent isolates of tomato bushy stunt virus (TBSV) upon serial passage at high multiplicities of infection (m.o.i.) in plants, but not in any of 4 additional isolates after 11 serial passages at low m.o.i. The DI RNAs were detected in RNA isolated from virus particles and in 2.3 M LiCl-soluble RNA fractions isolated from inoculated leaves. Symptom attenuation leading to persistent infections was closely correlated with the passage in which DIs first developed. Comparisons of nucleotide sequences of 10 cDNA clones from 2 DI RNA populations and with a previously characterized TBSV DI RNA revealed the same four regions of sequence from the TBSV genome were strictly conserved in each of the DI RNAs: the virus 5' leader sequence of 168 bases; a region of approximately 200-250 bases from the viral polymerase gene; approximately 70 bases from the 3' terminus of the viral p19 and p22 genes; and approximately 130 bases from the 3' terminal noncoding region. Conservation of the sequence motif present in all of the DIs suggests that there might be a common mechanism of DI formation as well as selection pressure to maintain sequences essential for replication and encapsidation.
在番茄丛矮病毒（TBSV）的12个独立分离株中，当在植物中以高感染复数（m.o.i.）连续传代时，会重新产生缺陷干扰（DI）RNA，但在低m.o.i.下连续传代11次后，4个额外的分离株中均未产生。在从病毒颗粒分离的RNA以及从接种叶片分离的2.3 M LiCl可溶RNA组分中检测到了DI RNA。导致持续感染的症状减轻与DI首次出现的传代密切相关。对来自2个DI RNA群体的10个cDNA克隆的核苷酸序列与先前表征的TBSV DI RNA进行比较，发现TBSV基因组的相同四个序列区域在每个DI RNA中都严格保守：168个碱基的病毒5'前导序列；来自病毒聚合酶基因的约200 - 250个碱基的区域；来自病毒p19和p22基因3'末端的约70个碱基；以及来自3'末端非编码区域的约130个碱基。所有DI中存在的序列基序的保守性表明，可能存在DI形成的共同机制以及维持复制和衣壳化所必需序列的选择压力。
