Horizontal gene transfer and genetic engineering of linear plasmid pLMA1 in Micrococcus luteus Fleming strain

Abstract

Micrococci are Gram-positive, G+C-rich, nonmotile, non-spore-forming actinomycetous bacteria. Micrococcus strains have proven to play important roles in the biodegradation of xenobiotics, bioremediation processes, production of biotechnologically important enzymes or bioactive compounds, as test strains in biological assays for lysozyme and antibiotics. They can also cause infections in immunocompromised humans. We recently reported the isolation and characterization of the first linear plasmids in different strains of Micrococcus from extreme environments in Argentina. Among them, linear plasmid pLMA1 (110 kb) proved to be linked to an erythromycin resistance phenotype. In this report we show that this plasmid can be transferred to the type strain of M. luteus (NCTC 2665) in a process most closely resembling conjugation. However, clear differences from the classical conjugative plasmid transfer were observed, indicating the existence of a specialized system. We were further able to perform genetic manipulations on the transferred plasmid, which will allow the functional investigation of the elements involved in the transfer process. In addition, the transfer ability of the linear plasmid pLMA1, together with the rather efficient method for its manipulation, can establish it as an useful tool for biotechnological purposes in the genus Micrococcus The authors would like to acknowledge the support from the Bayerisches Hochschulzentrum für Lateinamerika (BAYLAT).