Proposal for a new class within the phylum Proteobacteria , Acidithiobacillia classis nov., with the type order Acidithiobacillales , and emended description of the class Gammaproteobacteria

<jats:p>The order <jats:named-content xmlns:xlink="http://www.w3.org/1999/xlink" content-type="order" xlink:type="simple"> <jats:ext-link ext-link-type="uri" xlink:href="http://dx.doi.org/10.1601/nm.2196" xlink:type="simple"> <jats:italic>Acidithiobacillales</jats:italic> </jats:ext-link> </jats:named-content> was previously assigned to the class <jats:named-content xmlns:xlink="http://www.w3.org/1999/xlink" content-type="class" xlink:type="simple"> <jats:ext-link ext-link-type="uri" xlink:href="http://dx.doi.org/10.1601/nm.2068" xlink:type="simple"> <jats:italic>Gammaproteobacteria</jats:italic> </jats:ext-link> </jats:named-content>. Recent analyses have indicated that this order actually lies outside all the proteobacterial classes, as a sister group to the combined classes <jats:named-content xmlns:xlink="http://www.w3.org/1999/xlink" content-type="class" xlink:type="simple"> <jats:ext-link ext-link-type="uri" xlink:href="http://dx.doi.org/10.1601/nm.1616" xlink:type="simple"> <jats:italic>Betaproteobacteria</jats:italic> </jats:ext-link> </jats:named-content> and <jats:named-content xmlns:xlink="http://www.w3.org/1999/xlink" content-type="class" xlink:type="simple"> <jats:ext-link ext-link-type="uri" xlink:href="http://dx.doi.org/10.1601/nm.2068" xlink:type="simple"> <jats:italic>Gammaproteobacteria</jats:italic> </jats:ext-link> </jats:named-content>. We now confirm this result with multiprotein phylogenetic analysis of all the available genomes of members of the order <jats:named-content xmlns:xlink="http://www.w3.org/1999/xlink" content-type="order" xlink:type="simple"> <jats:ext-link ext-link-type="uri" xlink:href="http://dx.doi.org/10.1601/nm.2196" xlink:type="simple"> <jats:italic>Acidithiobacillales</jats:italic> </jats:ext-link> </jats:named-content> and representatives of all available bacterial orders, and propose the new proteobacterial class, <jats:italic>Acidithiobacillia</jats:italic>, with the type order <jats:named-content xmlns:xlink="http://www.w3.org/1999/xlink" content-type="order" xlink:type="simple"> <jats:ext-link ext-link-type="uri" xlink:href="http://dx.doi.org/10.1601/nm.2196" xlink:type="simple"> <jats:italic>Acidithiobacillales</jats:italic> </jats:ext-link> </jats:named-content>, comprising the families <jats:named-content xmlns:xlink="http://www.w3.org/1999/xlink" content-type="family" xlink:type="simple"> <jats:ext-link ext-link-type="uri" xlink:href="http://dx.doi.org/10.1601/nm.2197" xlink:type="simple"> <jats:italic>Acidithiobacillaceae</jats:italic> </jats:ext-link> </jats:named-content> and <jats:named-content xmlns:xlink="http://www.w3.org/1999/xlink" content-type="family" xlink:type="simple"> <jats:ext-link ext-link-type="uri" xlink:href="http://dx.doi.org/10.1601/nm.2203" xlink:type="simple"> <jats:italic>Thermithiobacillaceae</jats:italic> </jats:ext-link> </jats:named-content> with the type genus <jats:named-content xmlns:xlink="http://www.w3.org/1999/xlink" content-type="genus" xlink:type="simple"> <jats:ext-link ext-link-type="uri" xlink:href="http://dx.doi.org/10.1601/nm.2198" xlink:type="simple"> <jats:italic>Acidithiobacillus</jats:italic> </jats:ext-link> </jats:named-content>.</jats:p>