We are what we eat, so do aphids

Many studies are currently done on the human microbiota, mainly because its relevance to medicine. Characterization of the human and mice microbiota diversity and their responses to stress conditions and association with a range of illnesses are under deep investigation. Diet is one the factors affecting the human’s microbiota diversity. In our research, we showed that it is not different for aphids. Host plant impacts the aphid’s microbiota diversity, which may impact several of the aphid’s bioecological traits. Aphids are well known for their association with endosymbiont bacteria.

Fig. 1.

Almost all aphids harbor Buchnera aphidicola as an obligate symbiont and several other bacteria as facultative symbionts. Associations of facultative symbionts and aphids are quite variable in terms of diversity and prevalence across aphid species. Facultative symbionts can have a major impact on aphid fitness. A number of factors shape the outcome of the facultative symbiont-aphid association, including aphid genotype, bacterial genotype, geography, and host plant association. The effects of host plant on aphid-facultative symbiont associations are the least understood. We sequenced the 16S -V4 region of aphids using Illumina MiSeq platform. Field populations of the oligophagous aphid Aphis citricidus were collected from seven different Citrus plants based on their chloroplast types, which it is used to define Citrus phylogeny. We demonstrated that A. citricidus harbors very low symbiont diversity as compared to polyphagous aphids, and that host plant suitability and phylogeny influence the diversity and abundance of primary and secondary symbionts of A. citricidus. A comparison of the microbial diversity data we generated with the existing data on A. citricidus fitness based on Citrus chloroplast type strongly suggests that the microbial community of A. citricidus may respond to host plant suitability, with a decrease in the relative abundance of Buchnera as host suitability decreases. Curiously, the association with an unclassified Enterobacteriaceae determined as Cluster B showed the opposite pattern. Therefore, we suggest that the Cluster B symbiont may play key roles in helping A. citricidus to exploit less suitable host plants by complementing the contribution provided by Buchnera. Our work is one of the few to focus on oligophagous aphid species, and our data highlight the importance of considering models other than polyphagous, nearctic or palearctic aphid species in investigations of the microbiome diversity and functions.

Aline S Guidolin, Fernando L Cônsoli
Insect Interactions Lab., Department of Entomology and Acarology,
University of São Paulo – USP/ESALQ, Piracicaba- SP, Brazil

 

Publication

Symbiont Diversity of Aphis (Toxoptera) citricidus (Hemiptera: Aphididae) as Influenced by Host Plants.
Guidolin AS, Cônsoli FL
Microb Ecol. 2017 Jan

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