Multichassis Expression of Cyanobacterial and Other Bacterial Biosynthetic Gene Clusters

Heterologous expression of biosynthetic gene clusters (BGCs) is a powerful strategy for natural product (NP) discovery, yet achieving consistent expression across microbial hosts remains challenging. Here, we developed cross-phyla vector systems enabling the expression of BGCs from cyanobacteria and other bacterial origins in Gram-negative Escherichia coli, Gram-positive Bacillus subtilis, and two model cyanobacterial strains including unicellular Synechocystis PCC 6803 and filamentous Anabaena sp. PCC 7120. Following validation using constitutive and inducible expression of the enhanced yellow fluorescent protein (eYFP), we applied these vectors to express the shinorine and violacein BGCs in all four hosts. Promoter tuning, substrate feeding, BGC refactoring, and inducible control enhanced NP production and mitigated host toxicity. Notably, we demonstrated that B. subtilis can serve as a chassis for cyanobacterial NP BGC expression. Our results provide versatile expression platforms for probing BGC function and accelerating natural product discovery from diverse cyanobacterial and other bacterial lineages.