Genome Editing Methods for Bacillus subtilis

Bacillus subtilis is a widely studied Gram-positive bacterium that serves as an important model for understanding processes critical for several areas of biology including biotechnology and human health. B. subtilis has several advantages as a model organism: it is easily grown under laboratory conditions, it has a rapid doubling time, it is relatively inexpensive to maintain, and it is nonpathogenic. Over the last 50 years, advancements in genetic engineering have continued to make B. subtilis a genetic workhorse in scientific discovery. In this chapter, we describe methods for traditional gene disruptions, use of gene deletion libraries from the Bacillus Genetic Stock Center, allelic exchange, CRISPRi, and CRISPR/Cas9. Additionally, we provide general materials and equipment needed, strengths and limitations, time considerations, and troubleshooting notes to perform each method. Use of the methods outlined in this chapter will allow researchers to create gene insertions, deletions, substitutions, and RNA interference strains through a variety of methods custom to each application.