Gut Bacteria Associated With (Coleoptera: Cerambycidae) and Their Possible Roles in Host Plant Adaptations.

(Coleoptera: Cerambycidae) is an important native pest in the pine forests of northeast China and a dispersing vector of an invasive species . To investigate the bacterial gut diversity of larvae in different host species, and infer the role of symbiotic bacteria in host adaptation, we used 16S rRNA gene Illumina sequencing and liquid chromatography-mass spectrometry metabolomics processing to obtain and compare the composition of the bacterial community and metabolites in the midguts of larvae feeding on three host tree species: , var. , and Metabolomics in xylem samples from the three aforementioned hosts were also performed. Proteobacteria and Firmicutes were the predominant bacterial phyla in the larval gut. At the genus level, , unclassified_f__, , and -- were most dominant in and var. feeders, while --, , , and were most dominant in feeders. Bacterial communities were similar in diversity in and var. feeders, while communities were highly diverse in feeders. Compared with the other two tree species, xylems had more diverse and abundant secondary metabolites, while larvae feeding on these trees had a stronger metabolic capacity for secondary metabolites than the other two host feeders. Correlation analysis of the association of microorganisms with metabolic features showed that dominant bacterial genera in feeders were more negatively correlated with plant secondary metabolites than those of other host tree feeders.