Kinetics of accumulation of citrus tristeza virus RNAs.
Kinetics of accumulation of citrus tristeza virus RNAs.
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柑橘 tristeza 病毒 RNA 积累的动力学。
DOI：
10.1006/viro.1996.8369
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发表时间：
1997
期刊：
影响因子：
3.7
通讯作者：
W. O. Dawson
中科院分区：
文献类型：
--
作者：
J. Navas;M. R. Albiach;S. Gowda;M. Hilf;S. Garnsey;W. O. Dawson
柑橘衰退病毒(CTV)属于闭锁病毒属，是一种较为复杂的单链RNA病毒。它的19,296个核苷酸的单链RNA基因组的5‘端部分被表达为一个约400 kDa的蛋白质，而103’端的开放阅读框来自3‘端的共端亚基因组RNA(Sg RNAs)。作为对该病毒基因表达的初步检测，我们发现CTV T36分离物的基因组和sg RNA以及外壳蛋白在自然寄主柑橘和实验非寄主本氏烟草的原生质体中积累的动力学相似。新合成的基因组RNA在接种后2天检测到，并在3-5天达到高峰。与全长病毒粒子RNA互补的RNA以类似的动力学增加，但增加的浓度约为基因组+链的十分之一。大多数丰富的sg RNA也与基因组RNA的积累平行。然而，与p23基因相对应的最小sg RNA较早增加。不同sg RNA的积累量差异很大，总体上3‘-大多数sg RNA积累到比5’sg RNA更高的水平。然而，一些3‘sg RNA(p13和p18)积累到低水平。两个3‘端最大的sg RNA(p23和p20)积累到相当于基因组RNA的高水平。外壳蛋白的积累曲线与其mRNA的积累曲线平行，表明其调控是转录的。来自原生质体的子代病毒粒子被用来顺序地感染新的原生质体，作为潜在的病毒来源，可以在完整的植物中进化而不受遗传选择的影响来传播和移动蚜虫。
Citrus tristeza virus (CTV), a member of the closterovirus group, is one of the more complex single-stranded RNA viruses. The 5' portion of its 19,296-nt, single-stranded RNA genome is expressed as an approximately 400-kDa polyprotein that is proteolytically processed, while the 10 3' open reading frames are expressed from 3'-coterminal subgenomic RNAs (sg RNAs). As an initial examination of the gene expression of this virus, we found that the kinetics of accumulation of genomic and sg RNAs and coat protein of the T36 isolate of CTV were similar in protoplasts of the natural host, citrus, and the experimental nonhost Nicotiana benthamiana. Newly synthesized genomic RNA was detected 2 days postinoculation and increased to a maximum at 3-5 days. The RNA complementary to the full-length virion RNA increased with similar kinetics, but at approximately one-tenth the concentration of genomic plus strands. Most of the abundant sg RNAs also accumulated in parallel to that of the genomic RNA. However, the smallest sg RNA, which corresponds to the p23 gene, increased earlier. The different sg RNAs accumulated in greatly differing amounts, in general with 3'-most sg RNAs accumulating to higher levels than 5' sg RNAs. However, some 3' sg RNAs (p13 and p18) accumulated to low levels. The two 3'-most sg RNAs (p23 and p20) accumulated to high levels approximately equal to that of the genomic RNA. The accumulation curve for coat protein paralleled that of its mRNA, suggesting that its regulation was transcriptional. Progeny virions from protoplasts were used to sequentially infect new protoplasts, serving as a potential source of virus that could evolve free from the genetic selection in intact plants for aphid transmission and movement.