Tombusvirus p19-mediated suppression of virus-induced gene silencing is controlled by genetic and dosage features that influence pathogenicity
Tombusvirus p19-mediated suppression of virus-induced gene silencing is controlled by genetic and dosage features that influence pathogenicity
复制标题
DOI：
10.1094/mpmi.2002.15.3.269
复制
发表时间：
2002-03-01
影响因子：
3.5
通讯作者：
Scholthof, HB
中科院分区：
文献类型：
--
作者：
Qiu, WP;Park, JW;Scholthof, HB
番茄丛矮病毒（Tomato bushy stunt virus，TBSV）的p19蛋白（P19 protein，P19）是一种致病性决定因子，对病毒的传播和症状诱导具有宿主依赖性。此外，在这项研究中的结果证实，马铃薯病毒X介导的P19传递抑制转录后基因沉默（PTGS）。为了研究这种活性与TBSV生物学的相关性，我们评估了TBSV是否激活病毒诱导的基因沉默（VIGS）以及该过程是否被P19抑制。将具有绿色荧光蛋白（GFP）基因（对P19表达有活性或无活性）的TBSV载体接种到GFP转基因本氏烟草（Nicotiana benthamiana）植物上。在缺乏P19表达的情况下，VIGS被激活，如GFP mRNA和绿色荧光的消失所证明的。从TBSV载体的GFP和P19的共表达抑制VIGS，除了在新出现的叶子。抑制活性需要一个中央P19区域，这也是已知的宿主依赖性病毒传播和症状诱导所必需的。含有GFP基因3'末端的缺陷性干扰RNA（DI）非常有效地诱导沉默。伴随的DI引起的P19蓄积减少未能抑制该过程，类似于已知的P19对其他生物活性的剂量效应。总之，（i）TBSV及其DI是非常有效的VIGS诱导剂，（ii）P19是PTGS的强抑制剂，（iii）P19是VIGS的中度抑制剂，（iv）抑制剂活性受遗传和剂量特征的影响，这些特征对P19相关发病机制也很重要。
The p19 protein (P19) of Tomato bushy stunt virus (TBSV) is a pathogenicity determinant with host-dependent effects on virus spread and symptom induction. In addition, results in this study confirm that Potato virus X-mediated delivery of P19 suppresses posttranscriptional gene silencing (PTGS). To study the relevance of this activity for TBSV biology, we evaluated whether TBSV activates virus-induced gene silencing (VIGS) and if this process is suppressed by P19. TBSV vectors with the green fluorescent protein (GFP) gene, either active or inactive for P19 expression, were inoculated onto GFP-transgenic Nicotiana benthamiana plants. In the absence of P19 expression, VIGS was activated, as evidenced by the disappearance of GFP mRNA and green fluorescence. Coexpression of GFP and P19 from the TBSV vector suppressed VIGS, except in the newly emerging leaves. The suppressor activity required a central P19 region that is also known to be essential for host-dependent virus spread and symptom induction. Defective interfering RNAs (DIs) that contained the 3' end of the GFP gene induced silencing very effectively. The concomitant DI-instigated reduction in P19 accumulation failed to suppress this process, analogous to the known P19 dosage effects for other biological activities. In conclusion, (i) TBSV and its DIs are very effective inducers of VIGS, (ii) P19 is a strong suppressor of PTGS, (iii) P19 is a moderate suppressor of VIGS, and (iv) the suppressor activity is influenced by genetic and dosage features that are also important for P19-associated pathogenesis.