Effects Of Three Microbes On The Behavior And Development Of Drosophila Melanogaster

The intestinal tract of metazoans,including insects and humans,inhabits a large number of microorganisms,which form a symbiotic relationship with the host.Intestinal microorganisms play an important role in a variety of life activities of the host,and the interaction between intestinal microorganisms have become a hot research topic.As one of the important model organisms,Drosophila melanogaster is an ideal material to study the interaction between intestinal microorganism and host.The species of intestinal microbes in D.melanogaster are relatively simple,and it is easy to establish aseptic and gnotobiotic animal models.The intestinal microorganisms of Drosophila dynamically change with the state of Drosophila,and affect the health and longevity of the host.In this study,we selected two representative gut microbes in D.melanogaster,Lactobacillus plantarum and Acetobacter malorum,and the key microbe affecting foraging,feeding and oviposition choice of flies in environment,Saccharomyces cerevisiae,established trap assasy and oviposition assay of D.melanogaster.Foraging and oviposition behavior of D.melanogaster were detected by trap assasy and oviposition assay,the effects of different microbe mixtures on the regulation of foraging and oviposition behaviors of D.melanogaster were examined,and the effects of the three microbes on the development of D.melanogaster were also detected.Transcriptome sequencing and real-time fluorescence quantitative PCR were used to preliminarily explore the molecular mechanisms of different microbes on the behavior and development of D.melanogaster.The results of this study showed that the proportion of intestinal microbiota of D.melanogaster were changed when they were cultured with S.cerevisiae,L.plantarum and A.malorum,respectively.A.malorum mainly affected the oviposition of D.melanogaster,while L.plantarum and S.cerevisiae could affect both its foraging and oviposition.Compared with single microbe,the mixture of the two or three microbes had stronger attractiveness to non-virgin D.melanogaster.The oviposition preference assays showed that the three microbes had significant attractiveness to D.melanogaster,in a descending order of A.malorum > S.cerevisiae > L.plantarum.In addition,L.plantarum,A.malorum and S.cerevisiae could promote the development of D.melanogaster larvae.The live microbes accelerated the development of D.melanogaster larvae in the early stage of inoculation,while the promotion effect of the inactivated microbes lagged behind,which indicated that the three microorganisms may be involved in the growth and development of Drosophila through different regulatory mechanisms.Transcriptome sequencing results showed that S.cerevisiae had the largest effect on gene expression in Drosophila among the three microorganisms,followed by A.malorum,while L.plantarum had a relatively small effect,which was similar to the results of the previous behavioral experiment.The GO enrichment analysis of the differentially expressed genes in the head and body of Drosophila indicated that the three microorganisms may have different gene regulation functions in the head and body of Drosophila.Studies on the effects of L.plantarum,A.malorum and S.cerevisiae on the foraging,oviposition and development of D.melanogaster will be helpful to further elucidate the regulation mechanism of intestinal microbiome-host interaction.This study not only enriches the research on the regulation of host behavior by intestinal microorganisms,but also provides a basis for further study on the molecular mechanisms of intestinal microorganisms in the regulation of feeding,oviposition behavior and development of Drosophila,and provides a reference for further development of new biological control strategies.