CRISPR-Cas9-based genome-editing technologies in engineering bacteria for the production of plant-derived terpenoids

Terpenoids are widely used as medicines,flavors,and biofuels.However,the use of these natural products is largely restricted by their low abundance in native plants.Fortunately,heterologous biosynthesis of terpenoids in microorganisms offers an alternative and sustainable approach for efficient production.Various genome-editing technologies have been developed for microbial strain construction.Clustered regularly interspaced short palin-dromic repeats(CRISPR)-CRISPR associated protein 9(Cas9)is the most commonly used system owing to its outstanding efficiency and convenience in genome editing.In this review,the basic principles of CRISPR-Cas9 systems are briefly introduced and their applications in engineering bacteria for the production of plant-derived terpenoids are summarized.The aim of this review is to provide an overview of the current developments of CRISPR-Cas9-based genome-editing technologies in bacterial engineering,concluding with perspectives on the challenges and opportunities of these technologies.