Poster Presentation Society for Molecular Biology and Evolution Conference 2016

Blood ties: Metabolic convergence among gammaproteobacterial endosymbionts from blood-feeding arthropods and the Mexican leech Haementeria officinalis (#668)

Alejandro Manzano-Marín 1 , Alejandro Oceguera-Figueroa 2 , Amparo Latorre 1 , Luis F. Jiménez-García 3 , Andrés Moya 1
  1. ICBiBE. University of Valencia, Paterna, VALENCIA, Spain
  2. Laboratorio de Helmintología, Departamento de Zoología, Instituto de Biología, Universidad Nacional Autónoma de México, Distrito Federal, México
  3. Departamento de Biología Celular, Facultad de Ciencias, Universidad Nacional Autónoma de México, Distrito Federal, México

Endosymbiosis between eukaryotic hosts and microorganisms is a common phenomenon in insects, whose typically unbalanced diets are usually complemented by their obligate endosymbionts. While much interest and focus has been directed towards phloem-feeders like aphids and mealybugs, blood-feeders such as the Lone star tick (Amblyomma americanum), Glossina flies, and the human body louse (Pediculus humanus corporis) also depend on obligate endosymbionts to complement their B-vitamin-deficient diets, and thus are required for growth and survival. Strict blood-feeding glossiphoniid leeches, contrary to the predatory species, have also been found to harbour distinct endosymbionts belonging to the Gamma and Alphaproteobacteria housed in specialised morphologically-diverse organs. The Mexican leech, Haementeria officinalis is associated to the obligate endosymbiont Candidatus Providencia siddallii (Gammaproteobacteria) . This symbiont resides intracellularly in spherical bacteriomes attached to the oesophagus, and possesses a highly-reduced genome with high A+T content and a reduced set of metabolic capabilities, all of which are common characteristics of ancient obligate endosymbionts of arthropods. Its genome has retained many pathways related to the biosynthesis of B-vitamins, pointing towards a role in supplementing the blood-restricted diet of its host. Through genomic comparison against the endosymbionts of the different blood-feeding arthropods, we were able to detect a high degree of metabolic convergence among these very distantly related endosymbiotic bacteria. These findings strongly support the widespread and conserved metabolic dependence of the strict blood-feeders in their bacterial endosymbionts and the similar constraints these have undergone in their evolution as obligate nutritional partners.

  1. Smith TA, Driscoll T, Gillespie JJ, Raghavan R. A Coxiella-like endosymbiont is a potential vitamin source for the Lone Star tick. Genome Biol Evol. 2015;7: 831–8. doi:10.1093/gbe/evv016
  2. Akman L, Yamashita A, Watanabe H, Oshima K, Shiba T, Hattori M, et al. Genome sequence of the endocellular obligate symbiont of tsetse flies, Wigglesworthia glossinidia. Nat Genet. 2002;32: 402–7. doi:10.1038/ng986
  3. Kirkness EF, Haas BJ, Sun W, Braig HR, Perotti MA, Clark JM, et al. Genome sequences of the human body louse and its primary endosymbiont provide insights into the permanent parasitic lifestyle. Proc Natl Acad Sci U S A. 2010;107: 12168–12173. doi:10.1073/pnas.1003379107
  4. Manzano-Marín A, Oceguera-Figueroa A, Latorre A, Jiménez-García LF, Moya A. Solving a Bloody Mess: B-Vitamin Independent Metabolic Convergence among Gammaproteobacterial Obligate Endosymbionts from Blood-Feeding Arthropods and the Leech Haementeria officinalis. Genome Biol Evol. 2015;7: 2871–2884. doi:10.1093/gbe/evv188