Culturing under aerobic conditions led to the detection of nine bacterial genera in the RPW larval gut. Both pyrosequencing and culturing revealed that Enterobacteriaceae is the most represented bacterial family in the gut of

RPW larvae. In this work, the culture-based approach helped in obtaining a better description of some members of Enterobacteriaceae as the complete sequence of the 16S rRNA gene could be obtained from the isolated bacteria. The pyrosequencing approach, that relies upon a short 16S rRNA gene fragment, did not detect sequences of the genus Klebsiella, that was instead abundantly Akt inhibitor isolated by culturing. Failing of its detection could be due to low variability of the V2 region between Klebsiella and Enterobacter[12, 40] and the sequences of Klebsiella might have been included in the genus Enterobacter by the RDP Classifier software. Another genus detected by cultivation but absent in the 454 assemblage was Bacillus that might be present at very low levels in the RPW gut, so that its detection might be impaired by PCR biases. Bacilli isolated from the gut are close to selleck chemicals llc B. muralis and B. simplex, and cluster separately from palm endophyte bacilli and frass bacilli previously isolated, that

are related to the B. cereus/thuringiensis group. Cuticle Bacillus isolates, that survived sterilization procedures, form a separate cluster from gut bacilli and are closer to the Bacillus isolates previously obtained from frass and from healthy palms as endophytes [2] (Additional file 5). This suggest that they belong to a bacterial community external to the larvae, that might contribute to the fitness of larvae inside the plant tissues. The cuticle aerobic spore-forming bacteria might produce antimicrobial molecules that could negatively affect the sensitivity of the larvae to entomopathogenic fungi and bacteria [41]. A low bacterial diversity and the presence of a prevailing sugar-fermenting microbiota suggest that the digestion

of plant polymers (cellulose, hemicellulose) is not a primary BCKDHA function of the RPW larvae. However, cellulolytic and hemicellulolytic bacteria were previously isolated by enrichment cultures from the gut of RPW larvae and were mainly affiliated to the Gamma and Alphaproteobacteria of the genera Pseudomonas, Enterobacter Microbacterium and Paenibacillus [2]. The presence of these genera in the RPW gut was confirmed by pyrosequencing (Additional file 6). Matching the 454-reads with the 16S rRNA gene sequences of the gut cellulolytic isolates, we obtained up to 99% identity of cluster_3902 (3 sequences) with the cellulolytic isolate Pseudomonas sp. R-8 (Genbank accession JN167546) and 98% identity of five different clusters (for a total of 159 sequences) with the cellulolytic RPW gut isolate Enterobacter sp.