Characterisation of the symbionts in the Mediterranean fruit fly gut

Darrington, Mike, Leftwich, Philip T. ORCID: https://orcid.org/0000-0001-9500-6592, Holmes, Neil A., Friend, Lucy A., Clarke, Naomi V. E., Worsley, Sarah F., Margaritopolous, John T., Hogenhout, Saskia A., Hutchings, Matthew I. and Chapman, Tracey (2022) Characterisation of the symbionts in the Mediterranean fruit fly gut. Microbial Genomics, 8 (4). ISSN 2057-5858

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Abstract

Symbioses between bacteria and their insect hosts can range from loose associations through to obligate interdependence. While fundamental evolutionary insights have been gained from the in-depth study of obligate mutualisms, there is increasing interest in the evolutionary potential of flexible symbiotic associations between hosts and their gut microbiomes. Understanding relationships between microbes and hosts also offers the potential for exploitation for insect control. Here, we investigate the gut microbiome of a global agricultural pest, the Mediterranean fruit fly (Ceratitis capitata). We used 16S rRNA profiling to compare the gut microbiomes of laboratory and wild strains raised on different diets and from flies collected from various natural plant hosts. The results showed that medfly guts harbour a simple microbiome that is primarily determined by the larval diet. However, regardless of the laboratory diet or natural plant host on which flies were raised, Klebsiella spp. dominated medfly microbiomes and were resistant to removal by antibiotic treatment. We sequenced the genome of the dominant putative Klebsiella spp. (‘Medkleb’) isolated from the gut of the Toliman wild-type strain. Genome-wide ANI analysis placed Medkleb within the K. oxytoca / michiganensis group. Species level taxonomy for Medkleb was resolved using a mutli-locus phylogenetic approach - and molecular, sequence and phenotypic analyses all supported its identity as K. michiganensis. Medkleb has a genome size (5825435 bp) which is 1.6 standard deviations smaller than the mean genome size of free-living Klebsiella spp. Medkleb also lacks some genes involved in environmental sensing. Moreover, the Medkleb genome contains at least two recently acquired unique genomic islands as well as genes that encode pectinolytic enzymes capable of degrading plant cell walls. This may be advantageous given that the medfly diet includes unripe fruits containing high proportions of pectin. The results suggest that the medfly harbours a commensal gut bacterium that may have developed a mutualistic association with its host and provide nutritional benefits.

Item Type: Article
Uncontrolled Keywords: 16s rrna sequencing,klebsiella,paratransgenesis,symbiont,epidemiology,microbiology,molecular biology,genetics ,/dk/atira/pure/subjectarea/asjc/2700/2713
Faculty \ School: Faculty of Science
Faculty of Science > School of Biological Sciences
Related URLs:
Depositing User: LivePure Connector
Date Deposited: 22 Apr 2022 11:30
Last Modified: 23 Oct 2022 03:43
URI: https://ueaeprints.uea.ac.uk/id/eprint/84742
DOI: 10.1099/mgen.0.000801

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