Dual RNA sequencing of A. echinatior leafcutter ant laterocervical plates to establish secondary metabolite production by Pseudonocardia symbionts in vivo.

Actinobacteria are abundant in soil and well-known for producing antimicrobial compounds. Increasingly, members of this phylum are found to form symbiotic relationships and are thought to provide protection against host infection. However, it remains poorly understood how Actinobacteria can be selectively recruited to the host microbiome from the environment. Acromyrmex echinatior leafcutter ants transmit Pseudonocardia bacteria between generations and also recruit Streptomyces species to their cuticular microbiome. RNA-sequencing showed that genes encoding Pseudonocardia secondary metabolites were expressed in vivo on the ant cuticle, including bacteriocins and terpenes. Such molecules are used during interference competition and may play a role in selecting for an antibiotic-producing microbiome.