分析紋白蝶和甜菜夜蛾微孢子蟲分離株之rDNA親緣關係

Abstract

三種微孢子蟲分離株分別採集自不同地區之兩不同鱗翅目寄主：緣點紋白蝶(2株：AS-1和AS-2) 及甜菜夜蛾 (1株：SE)。為釐清分離株的分類地位，先進行rDNA基因之定序，紋白蝶微孢子蟲分離株 (AS-1) 之rDNA基因從 5’ 端始依序為SSU rDNA (16S) – ITS – LSU rDNA (23S)。另一紋白蝶微孢子蟲分離株 (AS-2) 及甜菜夜蛾微孢子蟲分離株 (SE) 則為LSU rDNA – ITS – SSU rDNA – IGS – 5S rDNA。根據rDNA序列之親緣關係分析的結果，將紋白蝶之二分離株分別命名為 Vairimorpha sp. AS-1 及 Nosema sp. AS-2；而來自甜菜夜蛾之分離株命名為Nosema sp. SE。 Nosema 屬甜菜夜蛾及紋白蝶微孢子蟲分離株 (Nosema sp. SE和Nosema sp. AS-2) 之整段 rDNA 基因已完成定序， Vairimorpha 屬紋白蝶微孢子蟲分離株 (Vairimorpha sp. AS-1) 之SSU rDNA，ITS 及部分 LSU rDNA 片段亦已完成定序工作。三株分離株的成熟孢子皆呈卵圓形，孢子周圍具折光性，孢子大小以ANOVA分析呈顯著差異。Vairimorpha sp. AS-1之成熟孢子具有單核及雙核兩種形式，而Nosema sp. AS-2及Nosema sp. SE僅具有雙核的孢子，印證了分子標誌之分析結果。根據親緣關係分析及形態觀察，推測 Vairimorpha sp. AS-1應為一新的種類， Nosema sp. SE應屬於含有 Nosema模式種之真微粒子蟲 (true Nosema) 種類，而Nosema sp. AS-2應屬於另一群Nosema 屬種類。

Three microsporidian isolates were collected from two different hosts, Artogeia canidia sordida (2 isolates, AS-1 and AS-2, from different locations in northern Taiwan) and Spodoptera exigua (1 isolate, SE, from middle Taiwan). For clarification of their taxonomic position, the rDNA genes of these isolates were sequenced. The rDNA gene arrangement of AS-1 was SSU rDNA (16S) – ITS – LSU rDNA (23S) from 5’ end while AS-2 and SE was LSU rDNA – ITS – SSU rDNA – IGS – 5S rDNA, which is similar to that of the true Nosema species. According to the phylogenetic analyses based on the gene sequences of rDNA, AS-1, AS-2 and SE was named as Vairimorpha sp. AS-1, Nosema sp. AS-2, and Nosema sp. SE, respectively. The rDNAs of the Nosema isolates were fully sequenced, and most rDNA sequences, including SSU rDNA, ITS and partial LSU rDNA, of the Vairimorpha isolates were carried out. The mature spores were oval and had great refringency. The sizes of the spores were significant difference by ANOVA analysis. The AS-1 contained mononuclear and binuclear spores, wherease only binuclear spores were found in AS-2 and SE isolates. This result confirmed the results of molecular makers. According to the results of the morphology observations and phylogenetic analyses, Vairimorpha sp. AS-1 should be a new species, SE should be grouped in the true Nosema complex while AS-2 belonged to other group of the Nosema species.