Metagenomics, paratransgenesis and the Anopheles microbiome: a portrait of the geographical distribution of the anopheline microbiota based on a meta-analysis of reported taxa

Abstract

Anophelines harbour a diverse microbial consortium that may represent an extended gene pool for the host. The proposed effects of the insect microbiota span physiological, metabolic and immune processes. Here we synthesise how current metagenomic tools combined with classical culture-dependent techniques provide new insights in the elucidation of the role of the Anopheles-associated microbiota. Many proposed malaria control strategies have been based upon the immunomodulating effects that the bacterial components of the microbiota appear to exert and their ability to express anti-Plasmodium peptides. The number of identified bacterial taxa has increased in the current “omics” era and the available data are mostly scattered or in “tables” that are difficult to exploit. Published microbiota reports for multiple anopheline species were compiled in an Excel® spreadsheet. We then filtered the microbiota data using a continent-oriented criterion and generated a visual correlation showing the exclusive and shared bacterial genera among four continents. The data suggested the existence of a core group of bacteria associated in a stable manner with their anopheline hosts. However, the lack of data from Neotropical vectors may reduce the possibility of defining the core microbiota and understanding the mosquito-bacteria interactive consortium.

Diversity of the Bacterial Microbiota of Anopheles Mosquitoes from Binh Phuoc Province, Vietnam

“…Due to the low resolution of TTGE fingerprints when the number of band is high, PCR-TTGE is only suitable for the description of microbiota with relative low richness as demonstrated for human neonatal microbiota (Jacquot et al, 2011) and surgical microbiota (Romano-Bertrand et al, 2014), but also for the description of mosquito microbiota (Manguin et al, 2013; Ngo et al, 2015). By this mean, we previously described most of the known repertory of bacterial taxa found in Asian Anopheles as shown by Villegas and Pimenta (2014). TTGE fingerprinting gave a good description of majority bacterial populations in mosquito microbiota, with a rather good sensitivity, as demonstrated by the extent of the taxonomic richness described herein compared to other studies even those which used Next Generation Sequencing (NGS; Villegas and Pimenta, 2014).…”

“…By this mean, we previously described most of the known repertory of bacterial taxa found in Asian Anopheles as shown by Villegas and Pimenta (2014). TTGE fingerprinting gave a good description of majority bacterial populations in mosquito microbiota, with a rather good sensitivity, as demonstrated by the extent of the taxonomic richness described herein compared to other studies even those which used Next Generation Sequencing (NGS; Villegas and Pimenta, 2014). Moreover, the use of PCR-TTGE in this study allowed a comparison with previous studies in Vietnam (Ngo et al, 2015), but also in Thailand (Manguin et al, 2013).…”

“…Concerning the pan-microbiota of the whole genus Anopheles , meta-analysis of recent studies (Gendrin and Christophides, 2013; Manguin et al, 2013; Minard et al, 2013; Sharma et al, 2014; Villegas and Pimenta, 2014; Ngo et al, 2015) and bibliography databases survey for older publications, indicated that 51 bacterial genera (48.6%) were probably detected herein for the first time in Anopheles (1 in Figure 3 and Supplementary Table 1). These newly described genera could be slightly overestimated due to the meta-analysis approach and the comparison with non-fully exhaustive data but it clearly suggested that the overall richness of Anopheles microbiome is far from being fully explored.…”

“…Within the bacteria detected in Anopheles specimens from Binh Phuoc, approximately half of the genera have previously been identified in the intra-abdominal microbiota of Anopheles populations from Thailand (Manguin et al, 2013), Vietnam (Manguin et al, 2013; Ngo et al, 2015), Cameroon (Boissière et al, 2012), Iran (Chavshin et al, 2012), India (Rani et al, 2009), or in reviews (Gendrin and Christophides, 2013; Minard et al, 2013; Hughes et al, 2014; Villegas and Pimenta, 2014). …”

Insect Vectors of Disease: Untapped Reservoirs for New Antimicrobials?

“…One exhaustive study examined the microbiome of Anopheles and nicely analyzed much of the data available, identifying a total of 109 unique genera with many different reported effects on the fitness of Plasmodium spp. but no overall role for the symbionts (Villegas et al, 2014). Although we should be best placed to determining the role of symbionts in mosquitos given the extensive number of studies performed, the complexity of the microbiome in different species has complicated this.…”