Genetic Structure of the Bacterial Endosymbiont Buchnera aphidicola from Its Host Aphid Schlechtendalia chinensis and Evolutionary Implications

Abstract

Buchnera aphidicola is a primary symbiotic bacterium which provides essential amino acids to aphids. In this study, we sequenced nuclear 16s rDNA and atpAGD genes for 156 individuals of B. aphidicola from eight geographically distant populations to investigate the genetic diversity and structure of B. aphidicola associated to the sumac gall aphid Schlechtendalia chinensis in central and southern China. Our analyses of the combined sequences showed that B. aphidicola from S. chinensis had high haplotype and nucleotide diversity (h = 0.893; π = 0.00164). One of the 16 haplotypes detected had a wide geographic distribution across the central and southern China and was probably the ancestral haplotype of B. aphidicola from S. chinensis. A network and phylogenetic analysis revealed a geographic structure in which the 16 haplotypes of B. aphidicola were divided into the northern and southern clades separated by the Yangtze River. The two clades diverged from each other at 22.1 ± 3.7 Mya according to our divergence time estimations. Therefore, the modern genetic structure in B. aphidicola from S. chinensis has been probably impacted by historical geological events. Combined with the data from GenBank, we also reconstructed the phylogenetic relationships of three aphid subfamilies and their symbiont bacteria. The results indicated significant topological correlations between the aphid and bacterial phylogenies at interspecific levels.

Potato leafroll virus reduces Buchnera aphidocola titer and alters vector transcriptome responses

“…Although their life history or host may change, all aphids depend on Buchnera aphidicola as their primary obligate endosymbiont 13 . Buchnera provide the aphid with essential amino acids and nutrients that are limited in the aphid’s diet 14 – 17 , and because of this aphids can no longer survive without Buchnera. For example, when Buchnera is reduced by using antibiotics, studies have shown lower body mass, lower fecundity, and changes to feeding behavior 18 , 19 .…”

Aphid endosymbiont facilitates virus transmission by modulating the volatile profile of host plants

“…Buchnera aphidicola, a primary symbiotic bacterium, provides essential amino acids for aphids. In turn, aphids offer B. aphidicola with nitrogenous substrates, including non-essential amino acids for the endosymbiont to produce essential amino acids [10]. It has been hypothesized that endosymbionts of insects contribute to the transmission of certain luteovirids and geminiviruses [11][12][13], although the evidences are debatable [14] .…”

“The green peach aphid,Myzus persicae,transcriptome in response to a circulative, nonpropagative polerovirus,Potato leafroll virus”

“…Although their lifestyle or host may change, all aphids depend on Buchnera aphidicola as their primary obligate endosymbiont (16). Buchnera provide the aphid with essential amino acids and nutrients that are limited in the aphid's diet (17)(18)(19)(20), and because of this aphids can no longer survive without Buchnera. For example, when Buchnera is reduced by using antibiotics,…”

“…In these experiments, the authors determined this interaction was due to direct impacts on the aphid and not due to virus induced changes in host plant quality by purifying BYDV virions and feeding them to aphids in artificial diet before conducting aphid bioassays.Although their lifestyle or host may change, all aphids depend on Buchnera aphidicola as their primary obligate endosymbiont (16). Buchnera provide the aphid with essential amino acids and nutrients that are limited in the aphid's diet (17)(18)(19)(20), and because of this aphids can no longer survive without Buchnera. For example, when Buchnera is reduced by using antibiotics,…”