ABSTRACT
Insects of the suborder Auchenorrhyncha harbour multiple ancient endosymbionts that jointly produce essential nutrients lacking from the host's diet. Compared to cicadas, leafhoppers, and spittlebugs, our understanding of the multipartite symbioses among planthoppers, an extremely diverse insect group, is still very limited. Herein, we assembled the genomes of the primary endosymbionts of two planthopper species from the Cixiidae family,
Cixius wagneri
and
Pentastiridius leporinus
, both vectors of phytopathogenic
Arsenophonus
in Europe. Each species harboured a different tripartite endosymbiont consortium: while
P. leporinus
carried the well‐known combination ‘
Candidatus
Karelsulcia muelleri’, ‘
Ca
. Vidania fulgoroideae’, and ‘
Ca
. Purcelliella pentastirinorum’,
C. wagneri
harboured a yet unknown
Gammaproteobacterium
in addition to
Karelsulcia
and
Vidania
. This new endosymbiont ‘
Ca
. Mirabilia symbiotica’ is likely much older than
Purcelliella
, considering its extremely reduced genome. In both species,
Karelsulcia
and
Vidania
jointly produce the 10 essential amino acids, whereas
Purcelliella
and
Mirabilia
provide the non‐essential amino acid cysteine and slightly different gene sets encoding B vitamins. Our findings confirm the functional stability of multipartite planthopper endosymbiont consortia despite changing partners over evolutionary time. In addition, we describe a new
Rickettsia
strain from the Meloidae group colonising
P. leporinus
, highlighting the diversity of bacterial endosymbionts associated with planthoppers.