文獻/Plant Journal：利用合成反式小干擾RNA多靶向病毒RNA增強植物抗病毒性

論文題目:Multi‐targeting of viral RNAs with synthetic trans‐acting small interfering RNAs enhances plant antiviral resistance。

研究內容：

基於RNA干擾（RNAi）的工具用於多種生物中，互補的小RNA通過靶定RNA的序列，特異性降解靶基因並誘導抗病毒抗性。在植物中，高度特異性的抗病毒RNAi工具包括人工微小RNA（amiRNA）和合成的反式作用小干擾RNA（syn-tasiRNA）。Syn-tasiRNA已成為一種有前途的抗病毒工具，可通過同時表達來自單一前體的幾種syn-tasiRNA來實現病毒RNA的多靶向。

在本研究中，作者在番茄中比較番茄斑萎病毒(TSWV)對表達單個amiRNA的amiRNA構建體和表達四種不同syn-tasiRNA的syn-tasiRNA構建體的影響。大多數syn-tasiRNA系對TSWV具有抗性，而大多數amiRNA系是易感的並且累積了具有amiRNA靶位點突變的病毒後代。

只有具有較高amiRNA積累的兩個amiRNA系具有抗性，而syn-tasiRNA系中的抗性不排除具有高syn-tasiRNA積累的系。

總的來說，這些結果表明syn-tasiRNAs誘導增強的抗病毒抗性，因為每個單獨的syn-tasiRNA的組合沉默效應，這最小化了病毒同時突變所有不同靶位點以完全逃避每個syn-tasiRNA的可能性。

RNA interference (RNAi)‐based tools are used in multiple organisms to induce antiviral resistance through the sequence‐specific degradation of target RNAs by complementary small RNAs. In plants, highly specific antiviral RNAi‐based tools include artificial microRNAs (amiRNAs) and synthetic trans‐acting small interfering RNAs (syn‐tasiRNAs). Syn‐tasiRNAs have emerged as a promising antiviral tool allowing multi‐targeting of viral RNAs through the simultaneous expression of several syn‐tasiRNAs from a single precursor.

Here we compared in tomato plants the effects againstTomato spotted wilt virus(TSWV) –an economically important pathogen affecting tomato crops worldwide– of an amiRNA construct expressing a single amiRNA and a syn‐tasiRNA construct expressing four different syn‐tasiRNAs. Most of the syn‐tasiRNA lines were resistant to TSWV, while the majority of the amiRNA lines were susceptible and accumulated viral progenies with mutations in the amiRNA target site. Only the two amiRNA lines with higher amiRNA accumulation were resistant, whilst resistance in syn‐tasiRNA lines was not exclusive of lines with high syn‐tasiRNA accumulation. Collectively, these results suggest that syn‐tasiRNAs induce enhanced antiviral resistance because of the combined silencing effect of each individual syn‐tasiRNA, which minimizes the possibility that the virus simultaneously mutates all different target sites to fully escape each syn‐tasiRNA.

素材來源：植物病毒與抗逆研究

編輯：蘇復

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