Utilization of Virus ϕCh1 Elements To Establish a Shuttle Vector System for Halo(alkali)philic Archaea via Transformation of Natrialba magadii

Abstract

ABSTRACT In the study described here, we successfully developed a transformation system for halo(alkali)philic members of the Archaea . This transformation system comprises a series of Natrialba magadii / Escherichia coli shuttle vectors based on a modified method to transform halophilic members of the Archaea and genomic elements of the N. magadii virus ϕCh1. The shuttle vector pRo-5, based on the repH -containing region of ϕCh1, stably replicated in E. coli and N. magadii and in several halophilic and haloalkaliphilic members of the Archaea not transformable so far. The ϕCh1 operon ORF53/ORF54 ( repH ) was essential for pRo-5 replication and was thus identified as the minimal replication origin. The plasmid allowed homologous and heterologous gene expression, as exemplified by the expression of ϕCh1 ORF34 52 , which encodes a structural protein, and the reporter gene bgaH of Haloferax lucentense in N. magadii . The new transformation/vector system will facilitate genetic studies within N. magadii and other haloalkaliphilic archaea and will allow the detailed characterization of the gene functions of N. magadii virus ϕCh1 in their extreme environments.