Genetic variation among endosymbionts of widely distributed vestimentiferan tubeworms
Genetic variation among endosymbionts of widely distributed vestimentiferan tubeworms
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DOI：
10.1128/aem.66.2.651-658.2000
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发表时间：
2000-02-01
影响因子：
4.4
通讯作者：
Cary, SC
中科院分区：
文献类型：
--
作者：
Di Meo, CA;Wilbur, AE;Cary, SC
Vstientiferan管虫在硫化深海热液喷口和冷渗漏中茁壮成长，受到它们对化学自养内共生体的营养依赖的限制。在最近使用16S核糖体DNA进行的系统发育研究中，我们发现来自喷口和渗漏生境的内生共生菌形成了两个不同的分支，每个分支内几乎没有变化。在本研究中，我们使用两种不同的方法来评估生物地理上不同的vstientiferan共生体之间的遗传差异，获得了与六个不同属的vstientiferan管虫相关的共生体rRNA操纵子的非编码内部转录间隔区(ITS)的DNA序列。从不同生境和广泛分布的喷口地点采集的寄主属内共生菌的ITS序列令人惊讶地保守。由于ITS区不足以区分来自不同生境或地点的细菌内共生菌，我们使用DNA指纹技术--重复基因外-回文聚合酶链式反应(Rep-PCR)来揭示细菌内共生菌基因组中重复序列分布的差异。大多数内共生菌表现出独特的REP-PCR图谱。根据这些指纹生成的分支图反映了可能受到各种因素影响的关系，包括寄主属、地理位置和底部类型。
Vestimentiferan tubeworms thriving in sulfidic deep-sea hydrothermal vents and cold seeps are constrained by their nutritional reliance on chemoautotrophic endosymbionts. In a recent phylogenetic study using 16S ribosomal DNA, we found that endosymbionts from vent and seep habitats form two distinct clades,vith little variation within each clade. In the present study, we used two different approaches to assess the genetic variation among biogeographically distinct vestimentiferan symbionts, DNA sequences were obtained for the noncoding, internal transcribed spacer (ITS) regions of the rRNA operons of symbionts associated with six different genera of vestimentiferan tubeworms. ITS sequences from endosymbionts of host genera collected from different habitats and widely distributed vent sites were surprisingly conserved. Because the ITS region was not sufficient for distinguishing endosymbionts from different habitats or locations, we used a DNA fingerprinting technique, repetitive extragenic-palindrome PCR (REP-PCR), to reveal differences in the distribution of repetitive sequences in the genomes of the bacterial endosymbionts. Most of the endosymbionts displayed unique REP-PCR patterns. A cladogram generated from these fingerprints reflected relationships that may be influenced by a variety of factors, including host genera, geographic location, and bottom type.