Erwiniaceae bacteria play defensive and nutritional roles in two widespread ambrosia beetles
Fecha
2023
Tipo
artículo original
Autores
Cambronero Heinrichs, Juan Carlos
Battisti, Andrea
Biedermann, Peter Hans Wilhelm
Cavaletto, Giacomo
Castro Gutiérrez, Víctor Manuel
Favaro, Lorenzo
Santoiemma, Giacomo
Rassati, Davide
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Resumen
Ambrosia beetles are fungal-growing insects excavating galleries deep inside the wood. Their success as invaders increased scientific interest towards them. However, most studies on their microbiota targeted their fungal associates whereas the role of bacterial
associates is understudied. To explore the role of abundant microbial associates, we isolated bacteria from active galleries of two
widespread ambrosia beetles, Xylosandrus crassiusculus and X. germanus. These isolates were classified within the Erwiniaceae family
and through a phylogenetic analysis including isolates from other insects we showed that they clustered with isolates obtained from
ambrosia and bark beetles, including Erwinia typographi. The whole genome analysis of the isolate from active galleries of X. crassiusculus suggested that this bacterium plays both a nutritional role, by providing essential amino acids and enzymes for the hydrolysis
of plant biomass, and a defensive role, by producing antibiotics. This defensive role was also tested in vitro against fungi, including
mutualists, common associates, and parasites. The bacteria inhibited the growth of some of the common associates and parasites
but did not affect mutualists. Our study supported the hypothesis of a mutualist role of Erwiniaceae bacteria in ambrosia beetles and
highlighed the importance of bacteria in maintaining the symbiosis of their host with nutritional fungi.
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Palabras clave
BACTERIA, SYMBIOSIS, INSECTS, BIOLOGY