沫蟬內共生物之親緣多樣性及共演化

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題名:	沫蟬內共生物之親緣多樣性及共演化
其他題名:	Phylogenetic Diversity and Cospeciation of Spittlebug’s Endosymbionts
作者:	陳薇云 Chen, Wei-Yun
貢獻者:	林仲平 Lin, Chung-Ping 東海大學生命科學系
關鍵詞:	親緣關係樹;沫蟬;懷菌體;內共生物;貝氏相對速率;穿透式電子顯微鏡;原位雜合實驗 Phylogeny;spittlebugs;bacteriomes;endosymbionts;Bayesian relative rates;TEM;in situ hybridization
日期:	2007
上傳時間:	2011-03-24T05:34:53Z (UTC)
摘要:	紅紋沫蟬內共生物之親緣多樣性及分子特徵共生關係的生活型態能增加多樣性的一種主要適應方式。許多昆蟲，尤其是半翅目，體內具有初級及次級內共生物。初級內共生物 (存在於懷菌體內) 提供寄主昆蟲所缺乏之養份，然而次級內共生物的功能尚不清楚。我們利用分生技術及親緣分析來描述紅紋沫蟬（Okiscarta uchidae）的內共生物特徵及他們在eubacteria內的親緣關係。我們也估算共生物的演化速率並且與自營菌的速率做比較。穿透式電子顯微鏡的照片顯示至少有兩種不同型態的內共生物在沫蟬的懷菌體內，而且其中一種內共生物的外部型態與酵母菌相似。16S rDNA的分析結果顯示分離出的內共生物分為四個類群，其中三個類群位於γ-proteobacteria內，一個類群在Bacteroidetes內。In situ Hybridization的結果顯示五種不同的內共生物位於懷菌體內。自營菌通常具有較快的演化速率，但紅紋沫蟬內共生物的演化速率往往是所有分析的菌種中最慢的，我們推測，這些內共生物應該屬於次級內共生物。 Symbiotic life style is a major adaptation of organisms that can increase their diversity. Many insects, especially hemipterans, are associated with the primary as well as secondary endosymbionts. The primary endosymbiont (bacteriome-associated) of insects provides their hosts with nutrition whereas the function of secondary endosymbionts is not clear. Here we used molecular phylogenetic analyses to describe the characteristics of bacterial endosymbionts in the red striped spittlebug, Okiscarta uchidae, and to investigate their phylogenetic placement within the eubacteria. We also evaluated relative evolutionary rates of endosymbionts and their free-living and pathogenic relatives. TEMs suggested that there were at least two types of endosymbionts in the bacteriomes, one of them are bacterial symbionts and the other are yeast-like organisms. Phylogenetic results suggested that there are four distinct symbiont lineages, three of them belonging to γ-proteobacteria and the other one clustered witnin the phylum Bacteroidetes. Results obtained from in situ hybridization suggested that five of the isolated endosymbionts were located inside the bacteriomes. In this study, we found that the evolutionary rates of identified symbionts were frequently the lowest among free-living, pathogenic and symbiont bacteria of insects, suggesting that they are most likely to be the “secondary” endosymbionts of O. uchidae.
顯示於類別:	[生命科學系所] 碩博士論文

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