Affiliation:
1. Department of Biology, University of California, Santa Cruz, Santa Cruz, California 95064
Abstract
ABSTRACT
The phylogenetic relationships of bacterial symbionts from three gall-bearing species in the marine red algal genus
Prionitis
(Rhodophyta) were inferred from 16S rDNA sequence analysis and compared to host phylogeny also inferred from sequence comparisons (nuclear ribosomal internal-transcribed-spacer region). Gall formation has been described previously on two species of
Prionitis
,
P. lanceolata
(from central California) and
P. decipiens
(from Peru). This investigation reports gall formation on a third related host,
Prionitis filiformis
. Phylogenetic analyses based on sequence comparisons place the bacteria as a single lineage within the
Roseobacter
grouping of the α subclass of the division
Proteobacteria
(99.4 to 98.25% sequence identity among phylotypes). Comparison of symbiont and host molecular phylogenies confirms the presence of three gall-bearing algal lineages and is consistent with the hypothesis that these red seaweeds and their bacterial symbionts are coevolving. The species specificity of these associations was investigated in nature by whole-cell hybridization of gall bacteria and in the laboratory by using cross-inoculation trials. Whole-cell in situ hybridization confirmed that a single bacterial symbiont phylotype is present in galls on each host. In laboratory trials, bacterial symbionts were incapable of inducing galls on alternate hosts (including two non-gall-bearing species). Symbiont-host specificity in
Prionitis
gall formation indicates an effective ecological separation between these closely related symbiont phylotypes and provides an example of a biological context in which to consider the organismic significance of 16S rDNA sequence variation.
Publisher
American Society for Microbiology
Subject
Ecology,Applied Microbiology and Biotechnology,Food Science,Biotechnology
Cited by
93 articles.
订阅此论文施引文献
订阅此论文施引文献,注册后可以免费订阅5篇论文的施引文献,订阅后可以查看论文全部施引文献