Rhodococcus: sequences of genetic parts, analysis of their functionality, and development prospects as a molecular biology platform

Rhodococcus bacteria are a fast-growing platform for biocatalysis, biodegradation, and biosynthesis, but not a platform for molecular biology. That is, Rhodococcus are not convenient for genetic engineering. One major issue for the engineering of Rhodococcus is the absence of a publicly available, curated, and commented collection of sequences of genetic parts that are functional in biotechnologically relevant species of Rhodococcus (R. erythropolis, R. rhodochrous, R. ruber, and R. jostii). Here, we present a collection of genetic parts for Rhodococcus (vector replicons, promoter regions, regulators, markers, and reporters) supported by a thorough analysis of their functionality. We also highlight and discuss the gaps in Rhodococcus-related genetic parts and techniques, which should be filled in order to make these bacteria a full-fledged molecular biology platform independent of Escherichia coli. We conclude that all major types of required genetic parts for Rhodococcus are available now, except multicopy replicons. As for model Rhodococcus strains, there is a particular shortage of strains with high electrocompetence levels and strains designed for solving specific genetic engineering tasks. We suggest that these obstacles are surmountable in the near future due to an intensification of research work in the field of genetic techniques for non-conventional bacteria.