Multiple origins of interdependent endosymbiotic complexes in a genus of cicadas

Abstract

Significance Highly reduced genomes from bacteria that are long-term beneficial endosymbionts of insects often show remarkable structural stability. Endosymbionts in insects diverged by tens or hundreds of millions of years often have genomes almost completely conserved in gene order and content. Here, we show that an endosymbiont in some cicadas has repeatedly and independently fractured into complexes of distinct genomic and cellular lineages present in the same host. Individual endosymbiont lineages, having lost many of the essential ancestral genes, rely on each other for basic function and together seem to provide the same nutritional benefits as the ancestral single symbiont. These cicada endosymbionts show genomic parallels to mitochondria and provide another example of how normally stable genomes can lose structural stability.