P25 and P37 proteins encoded by firespike leafroll-associated virus are viral suppressors of RNA silencing.
P25 and P37 proteins encoded by firespike leafroll-associated virus are viral suppressors of RNA silencing.
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DOI：
10.3389/fmicb.2022.964156
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发表时间：
2022
影响因子：
5.2
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中科院分区：
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火状卷叶相关病毒（FLRaV）是引起筒状齿线虫卷叶病的主要病原。系统发育分析表明，FLRaV具有典型的安培病毒亚组II成员的特征，但编码两个额外的蛋白，P25和P37。在此，我们确定了P25蛋白的微丝定位。转录后基因沉默（PTGS）实验表明，FLRaV P25和P37均能抑制局部和全身PTGS，FLRaV P25能抑制由正义RNA诱导的PTGS（S-PTGS）和反向重复RNA诱导的PTGS（IR-PTGS）引起的绿色荧光蛋白（GFP）基因沉默。相比之下，FLRaV P37仅能够抑制由S-PTGS而不是IR-PTGS触发的GFP沉默。在转录基因沉默（TGS）测定中，发现仅FLRaV P25能够逆转16-TGS植物中建立的TGS介导的GFP沉默。FLRaV P25能加重马铃薯X病毒在N.本萨米亚纳这些结果表明，FLRaV P25和P37可能在克服宿主RNA沉默方面具有关键作用，这为我们理解FLRaV感染的分子机制提供了关键见解。
Firespike leafroll-associated virus (FLRaV) is a major pathogen associated with firespike (Odontonema tubaeforme) leafroll disease. Phylogenetic analysis showed that FLRaV possesses typical traits of subgroup II members of ampeloviruses, but encodes two additional proteins, P25 and P37. Here, we determined the microfilament localization of P25 protein. Posttranscriptional gene silencing (PTGS) assay showed that both FLRaV P25 and P37 were able to suppress the local and systemic PTGS and FLRaV P25 was capable of suppressing the green fluorescent protein (GFP) gene silencing triggered by both sense RNA-induced PTGS (S-PTGS) and inverted repeat RNA-induced PTGS (IR-PTGS). In contrast, FLRaV P37 was only able to inhibit the GFP silencing triggered by the S-PTGS but not the IR-PTGS. In the transcriptional gene silencing (TGS) assay, only FLRaV P25 was found to be able to reverse established TGS-mediated silencing of GFP in 16-TGS plants. We also found that FLRaV P25 could aggravate the disease symptom and viral titer of potato virus X in N. benthamiana. These results suggest that FLRaV P25 and P37 may have crucial roles in overcoming host RNA silencing, which provides key insights into our understanding of the molecular mechanisms underlying FLRaV infection.