Complex evolutionary history of the Aeromonas veronii group revealed by host interaction and DNA sequence data
Basic science / phylogenetics published in PLoS One (2011)
Abstract
Aeromonas veronii biovar sobria, Aeromonas veronii biovar veronii, and Aeromonas allosaccharophila are a closely related group of organisms, the Aeromonas veronii Group, that inhabit a wide range of host animals as a symbiont or pathogen. In this study, the ability of various strains to colonize the medicinal leech as a model for beneficial symbiosis and to kill wax worm larvae as a model for virulence was determined. Isolates cultured from the leech out-competed other strains in the leech model, while most strains were virulent in the wax worms. Three housekeeping genes, recA, dnaJ and gyrB, the gene encoding chitinase, chiA, and four loci associated with the type three secretion system, ascV, ascFG, aexT, and aexU were sequenced. The phylogenetic reconstruction failed to produce one consensus tree that was compatible with most of the individual genes. The Approximately Unbiased test and the Genetic Algorithm for Recombination Detection both provided further support for differing evolutionary histories among this group of genes. Two contrasting tests detected recombination within aexU, ascFG, ascV, dnaJ, and gyrB but not in aexT or chiA. Quartet decomposition analysis indicated a complex recent evolutionary history for these strains with a high frequency of horizontal gene transfer between several but not among all strains. In this study we demonstrate that at least for some strains, horizontal gene transfer occurs at a sufficient frequency to blur the signal from vertically inherited genes, despite strains being adapted to distinct niches. Simply increasing the number of genes included in the analysis is unlikely to overcome this challenge in organisms that occupy multiple niches and can exchange DNA between strains specialized to different niches. Instead, the detection of genes critical in the adaptation to specific niches may help to reveal the physiological specialization of these strains.
Abstract sourced from PubMed (NCBI) for the cited record. See the original publication for the authoritative version.
Резюме
Multilocus phylogenetic analysis and host-interaction studies (leech colonization, wax worm virulence) of the Aeromonas veronii group, revealing horizontal gene transfer that obscures vertical inheritance signals among niche-adapted strains.
Почему это важно для гирудотерапии
This study investigated the evolutionary relationships within the Aeromonas veronii group (A. veronii biovar sobria, biovar veronii, and A. allosaccharophila) by sequencing multiple housekeeping and virulence-associated genes and testing the ability of various strains to colonize the medicinal leech as a model of beneficial symbiosis and to kill wax worm larvae as a virulence model. Isolates cultured from the leech outcompeted other strains in the leech colonization model, and phylogenetic analyses revealed complex evolutionary histories with significant horizontal gene transfer among strains, complicating species-level resolution. For ASH's domain, this is relevant to understanding the specificity and adaptation of Aeromonas symbionts in the medicinal leech gut, with potential implications for strain-level considerations in leech rearing and hirudotherapy-associated microbiology. The caveat is that this is a molecular evolution and comparative genomics study; it provides no clinical data, no leech therapy outcomes, and no direct guidance for hirudotherapy practice.
Цитирование
Complex evolutionary history of the Aeromonas veronii group revealed by host interaction and DNA sequence data.
Silver AC et al. · PLoS One, 2011
Связанный клинический контекст
Узнайте, как это исследование связано с клинической практикой
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