AUTHOR=Ge Si-Xun , Shi Feng-Ming , Pei Jia-He , Hou Ze-Hai , Zong Shi-Xiang , Ren Li-Li 

TITLE=Gut Bacteria Associated With Monochamus saltuarius (Coleoptera: Cerambycidae) and Their Possible Roles in Host Plant Adaptations

JOURNAL=Frontiers in Microbiology

VOLUME=12

YEAR=2021

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2021.687211

DOI=10.3389/fmicb.2021.687211

ISSN=1664-302X

ABSTRACT=<p><italic>Monochamus saltuarius</italic> (Coleoptera: Cerambycidae) is an important native pest in the pine forests of northeast China and a dispersing vector of an invasive species <italic>Bursaphelenchus xylophilus</italic>. To investigate the bacterial gut diversity of <italic>M. saltuarius</italic> 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: <italic>Pinus koraiensis</italic>, <italic>Pinus sylvestris</italic> var. <italic>mongolica</italic>, and <italic>Pinus tabuliformis.</italic> 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, <italic>Klebsiella</italic>, unclassified_f__<italic>Enterobacteriaceae</italic>, <italic>Lactococcus</italic>, and <italic>Burkholderia</italic>–<italic>Caballeronia</italic>–<italic>Paraburkholderia</italic> were most dominant in <italic>P. koraiensis</italic> and <italic>P. sylvestris</italic> var. <italic>mongolica</italic> feeders, while <italic>Burkholderia</italic>–<italic>Caballeronia</italic>–<italic>Paraburkholderia</italic>, <italic>Dyella</italic>, <italic>Pseudoxanthomonas</italic>, and <italic>Mycobacterium</italic> were most dominant in <italic>P. tabuliformis</italic> feeders. Bacterial communities were similar in diversity in <italic>P. koraiensis</italic> and <italic>P. sylvestris</italic> var. <italic>mongolica</italic> feeders, while communities were highly diverse in <italic>P. tabuliformis</italic> feeders. Compared with the other two tree species, <italic>P. tabuliformis</italic> 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 <italic>P. tabuliformis</italic> feeders were more negatively correlated with plant secondary metabolites than those of other host tree feeders.</p>