Molecular Diversity Analysis Of The Intestinal Bacterial Communities From Adult Bactrocera Tau (Walker) And Their Trapping Effect

As an important worldwide quarantine pest species, Bactrocera tau (Walker) (Diptera:Tephritidae) is very difficult to control owning to the characteristics of omnivorous feeding, wide host range, strong reproductive capacity and cause great economic loss to fruit and vegetable industry and its foreign trade every year. In this research, we firstly studied the intestinal bacterial diversity and community structure in different developmental stages of female and male B.tau adults using the 16S rDNA (V3-V4 hypervariable region) high-throughput sequencing. Based on this, the gut bacteria of sexually mature female and male B.tau were isolated and identified using the tradition isolation and 16S rDNA (V3-V4 hypervariable region) sequencing methods. Meanwhile, it was evaluated that metabolites of bacterial species can trap this fruit fly species. Perhaps, this study would provide a new knowledge and scientific evidence for the biological control while also further research about functions of gut bacteria in B.tau. The main results are summarized as followings:On the phylum level, the gut bacterial communities from non-feeding female adult B.tau displayed a highly diversified composition including 10 bacterial phyla: Proteobacteria, Bacteroidetes, Firmicutes, Actinobacteria, Acidobacteria, Chlamydiae, Gemmatimonadetes, Candidatus_Saccharibacteria, Fusobacteria and Parcubacteria. The gut bacterial communities from non-feeding male adult B.tau can be classified into 11 bacterial phyla:Proteobacteria, Bacteroidetes, Firmicutes, Actinobacteria, Acidobacteria, Deferribacteres, Chlamydiae, Gemmatimonadetes, Candidatus-Saccharibacteria, Fusobacteria and Parcubacteria. The gut bacterial communities from 10-day-old female adult B.tau had the four bacterial phyla: Proteobacteria, Bacteroidetes, Firmicutes and Actinobacteria, and the gut communities from the 10-day-old female, mature female and male adult B.tau had the same three bacterial phyla:Proteobacteria, Bacteroidetes and Firmicutes. The results showed that the non-feeding female and male adult B.tau had the more abundance bacteria than another four samples, but Proteobacteria, Bacteroidetes and Firmicutes were the predominant phyla in the all samples.On the class level, Gammaproteobacteria was the predominant class in the gut of non-feeding female adult B.tau. Bacilli, Gammaproteobacteria, Flavobacteria and Bacteroidia were the predominant class in the gut of non-feeding male adult B.tau. Bacteroidia and Gammaproteobacteria were the predominant class in the gut of 10-day-old female and male, mature female and male adult B.tau.On the order level, Enterobacteriales, Bacteroidales and Vibrionales were the predominant order in the gut of non-feeding female adult B.tau. Enterobacteriales, Bacteroidales, Orbales, Lactobacillales, Flavobacteriales, Sphingobacteriales, Pseudomonadales, Bacillales, Burkholderiales, Actinomycetales, Xanthomonadales and Clostridiales were the principle order in the gut of non-feeding male adult B.tau. Enterobacteriales and Bacteroidales were the predominant order in the gut of 10-day-old adult female B.tau. The principle order in the gut of 10-day-old male adult B.tau were Enterobacteriales, Bacteroidales and Orbales. The main order in the gut of mature female B.tau were Enterobacteriales, Bacteroidales, Orbales, Lactobacillales and Aeromonadales. The principle order in the gut of mature male B.tau were Enterobacteriales, Bacteroidales, Orbales and Lactobacillales, respectively.On the family level, the predominant family from the gut of non-feeding female adult B. tau were Enterobacteriaceae and Vibrionaceae. The principle family from the gut of non-feeding male adult B.tau were Enterobacteriaceae, Porphyromonadaceae, Orbaceae, Enterococcaceae, Flavobacteriaceae, Bacteroidaceae, Pseudomonadaceae, Sphingobacteriaceae, Xanthomonadaceae, Planococcaceae, Prevotellaceae, Chitinophagaceae, Lachnospiraceae and Comamonadaceae, separately. The predominant family from the gut of 10-day-old female adult B.tau were Enterobacteriaceae and Porphyromonadaceae. The main family from the gut of 10-day-old male adult B.tau were Enterobacteriaceae, Porphyromonadaceae and Orbaceae. The principle family from the gut of mature female B.tau were Enterobacteriaceae, Porphyromonadaceae, Orbaceae, Enterococcaceae and Aeromonadaceae. The principle family from the gut of mature male B.tau were Enterobacteriaceae, Porphyromonadaceae, Orbaceae, Enterococcaceae, respectively.On the genus level, Enterobacter, Klebsiella, and Providencia were the predominant genus in the gut of non-feeding female adult B. tau. Chryseobacterium, Flavobacterium, Orbus, Bacteroides, Orbus, Stenotrophomonas, Enterobacter, Providencia, Serratia and Pseudomonas were the predominant genus of non-feeding male adult B.tau. Providencia, Enterobacter, Dysgonomonas and Serratia were the predominant genus of 10-day-old female adult B.tau. Enterobacter, Providencia, Dysgonomonas and Orbus were the predominant genus of 10-day-old male adult B.tau. Providencia, Orbus, Serratia, Enterobacter, Dysgonomonas and Cronobacter were the predominant genus of mature female B.tau. Orbus, Serratia, Dysgonomonas and Enterobacter were the predominant genus of mature male B.tau.Differential analysis of intestinal flora between six samples and groups indicated that there exists some differences in the gut composition and structure from the female or male adult B.tau in different stages but similar structure and composition was found in the same developmental stage male or female intestinal microflora.41 strains of bacteria were isolated and identified from the intestinal tract of sexually mature female and male B.tau, which all belong to Enterobactericeae, which both females and males had in common of its bacterial genera were Enterobacter, Providencia and Serratia.The laboratory bioassays showed the autoclaved supernatants from all strains being significantly more attractive to adult B.tau. The autoclaved supernatants of Enterobacter cloacae (BF16), Enterobacter sp. (BF(12)), Enterobacter sp. (BF23) and Enterobacter sp. (BF(32)) were the most attractive bacteria to 8-day-old and sexually mature B.tau. The indoor attractive rate to 8-day-old adult B.tau were 24.33%,20.67%,14.67% and 14.00%, and the outdoor attractive rate were 9.61%, 5.61%,6.06% and 8.83%, respectively. The outdoor attractive rate to sexually mature B.tau were 25.33%,20.33%,21.00% and 21.67%, and the outdoor attractive rate were 1.06%,4.56%,7.56% and 6.57%, respectively.