Characterization of the skin microbiome from bovine breeds genetically resistant and susceptible to infestations with the cattle tick, Rhipicephalus microplus

• Grant number: 12/13708-9
• Support Opportunities: Regular Research Grants
• Start date: October 01, 2012
• End date: September 30, 2013
• Field of knowledge: Biological Sciences - Parasitology - Entomology and Malacology of Parasites and Vectors
• Principal Investigator: Isabel Kinney Ferreira de Miranda Santos
• Grantee: Isabel Kinney Ferreira de Miranda Santos
• Host Institution: Faculdade de Medicina de Ribeirão Preto (FMRP). Universidade de São Paulo (USP). Ribeirão Preto , SP, Brazil
• Associated researchers: Alessandra Mara Franzin ; Cecília José Veríssimo ; Sandra Regina Costa Maruyama

Abstract

Background: The cattle tick, Rhipicephalus microplus, presents exquisite preference for bovines, but indicine breeds are highly resistant to infestations with this parasite. Host-vector specificity is dictated by the repertoire of semiochemicals produced by hosts, which may differ between bovines presenting contrasting, heritable phenotypes of tick infestations. Many semiochemicals are generated by the action of skin microbiota upon host secretions. The diversity and abundance of microbiota in anatomical niches of mice and men is determined by the genetic composition of individuals, is correlated with expression of different antimicrobial peptides and results in differential attractiveness to vectors. Preliminary Results: 1) genes encoding antimicrobial peptides are differentially expressed between two bovine breeds that are genetically tick-resistant or tick susceptible; 2) the composition of the fecal microbiome of the breeds presents significant differences in the abundance of certain genera; 3) skin rubbings from the breeds present different attractiveness to R. microplus. Objectives: Describe the skin microbiome from two commercial bovine breeds that are resistant or susceptible to R. microplus. Methods: 16S rRNA genes will be amplified from DNA extracted from skin microbes using primers for V5-V6 16S RNA regions followed by pyrosequencing. Microbial biodiversity and richness indexes will be extracted. Taxonomic assignment and richness will be achieved at phylum, family and genus level. We will analyze the literature available on differentially represented genera in order to determine if there is diversity that can be related to production of semiochemicals that affect tick behavior. Expected Results: We will determine if there are differences in the composition of skin microbial communities of two breeds of bovines presenting contrasting, heritable phenotypes of tick infestations.Key Words: skin microbiome; tick infestations; semiochemistry; genetic resistance (AU)