Microbial communities in different developmental stages of the Oriental fruit fly, Bactrocera dorsalis, are associated with differentially expressed peptidoglycan recognition protein-encoding genes

Abstract

The insect microbiota can change dramatically to enable adaptation of the host in different developmental stages and environments; however, little is known about how the host maintains its microbiota to achieve such adaptations. In this study, 16S rRNA sequencing revealed that the microorganisms in larvae and adults of the Oriental fruit fly, Bactrocera dorsalis, are primarily Gram-negative bacteria but that the major components in pupae are Gram-positive bacteria. Using suppression subtractive hybridization (SSH) and transcriptome analysis, we screened two specifically expressed genes encoding peptidoglycan recognition proteins (PGRP-LB and PGRP-SB1) and analyzed their relationship to B. dorsalis microbial communities. Knockdown of the PGRP-LB gene in larvae and adults led to increased ratios of Gram-positive bacteria; knockdown of the PGRP-SB1 gene in pupae led to increased ratios of Gram-negative bacteria. Our results suggest that maintenance of the microbiota in different developmental stages of B. dorsalis may be associated with the PGRP-LB and PGRP-SB1 genes.