Evidence for the establishment of aphid-eubacterium endosymbiosis in an ancestor of four aphid families

TLDR

Aphids harbor essential eubacterial endosymbionts within specialized cells called mycetocytes. Phylogenetic analysis of 16S rRNAs from 11 aphid species shows the endosymbionts are monophyletic and mirror host relationships, implying the association arose in a common ancestor of the four aphid families.

Abstract

Aphids (superfamily Aphidoidea) contain eubacterial endosymbionts localized within specialized cells (mycetocytes). The endosymbionts are essential for the survival of the aphid hosts. Sequence analyses of the 16S rRNAs from endosymbionts of 11 aphid species from seven tribes and four families have indicated that the endosymbionts are monophyletic. Furthermore, phylogenetic relationships within the symbiont clade parallel the relationships of the corresponding aphid hosts. Our findings suggest that this endocytobiotic association was established in a common ancestor of the four aphid families with subsequent diversification into the present species of aphids and their endosymbionts.