咸豐草斑駁病毒矮牽牛分離株之基因體譯讀與分析

Molecular Analysis of the Complete Viral Genome of Bidens Mottle Virus Isolated from Petunia Hybrid

咸豐草斑駁病毒在分類上是屬於 Potyvirus，為 ssRNA（+）病毒。本研究之目的是 解譯 2005 年發現之感染矮牽牛（Petunia hybrida）植株之咸豐草斑駁病毒株（Bidens mottle virus pet isolate, BiMoV-pet）之基因體並分析其產生蛋白質特性，並與已報告之 病毒株做比較。本研究以機械方式將病毒接種於奎藜後，抽取植物 total RNA，利用 反轉錄作用（Reverse transcription）合成第一股 cDNA，再以 PCR 技術增幅比對感染矮 牽牛之咸豐草斑駁病毒基因體 RNA。研究結果發現，BiMoV-pet 的基因體全長有 9746 個鹼基，不包括 poly A tail，其鹼基組成為 3133 個 A （32.22%）、1955 個 C （20.11%）、 2120 個 G （21.80%）、2515 個 T （25.87%），終止密碼子（Stop codon）為 TAA，其單一轉 譯片段可以轉譯出一含有 3071 個胺基酸之 polyprotein。從 5'端到 3'端可依序解譯出 P1、HC-Pro、P3、6K1、CI、6K2、VPg、NIa、NIb、CP 等基因。全長基因與 NCBI 的 Genbank 中 BiMoV 的 B3、B4、B12、HL、WF 等不同系統間皆有 97%以上之相 似度。將所得的序列與上述 5 種 BiMoV 比較各種基因間保留度，發現於 P1、P3 基 因保留度較低。於 P1、P3、6K1、CI、NIa、NIb、CP 等處皆有發現於 Potyvirus 屬中保留的 Motif 胺基酸序列，且各基因間之切位序列與文獻所示相同。本研究為 BiMoV 感染矮牽牛分離株基因體全長度定序及其分子特性之首次報告。

Bidens mottle virus belonging to Gena of Potyvirus with ssRNA(+). The purpose of this research was to clone and sequence genome of Bidens mottle virus pet isolate (BiMoV-pet) found in 2005, and compare its genome with other BiMoV isolates. The virus from dry leave of Petunia hybrida was inoculated mechanically on Chenopodium quinoa and total RNA was purified. cDNAs of genomic RNA of BiMoV-pet were obtained by reverse transcription and PCR amplification technology. Nucleotide and amino acid sequences of cDNAs amplified from genomic RNA of BiMoV-pet was analyzed and compared. Genomic RNA of BiMoV-pet had 9746 nucleotides, excluding the poly(A) tail, and base compositions were 3133 adenine (32.22%), 1955 cytosine (20.11%), 2120 guanine (21.80%), 2515 Thymine (25.87%) and a stop codon of TAA, respectively. From 5′ to 3′ end, the genomic RNA of BiMoV-pet contained 3071 amino acids in one open reading frame (ORF) which encoded proteins of P1、HC-Pro、P3、6K1、CI、6K2、VPg、 NIa、NIb、CP, respectively. In comparison of nucleotide sequences between BiMoV-pet and B3、B4、B12、HL、WF isolates of BiMoV in Genbank of NCBI had identities above 97%. When compared each genes of genome among pet and B3、B4、B12、HL、WF isolates of BiMoV showed that P1 and P3 had lower conservation. In addition, Deduced amino acid sequences of these genes were found similar to the conserved motif, and cutting sites of potyviruses. The results confirmed that BiMoV-pet is a isolate of BiMoV and a first report infecting Petunia hybrida.