ABSTRACT: Transcriptional responses in the gut of the main malaria vector Anopheles gambiae following oral bacterial infection with the entomopathogen Serratia marcescens were identified using DNA microarrays. S. marcescens is a common member of the mosquito gut microbiota, found in both laboratory reared and field collected mosquitoes, that can be potentially pathogenic as in Drosophila (Nehme et al., 2007), while it has been shown to influence the outcome of Plasmodium infections (Bando et al., 2013). S. marcescens belongs to the Enterobacteriaceae family, members of which have been shown to influence malaria transmission dynamics (Cirimotich et al., 2011, Boissiere et al., 2012). To further investigate the interactions between S. marcescens and the mosquito host, likely to shape, directly or indirectly, malaria transmission dynamics, An. gambiae mosquitoes, from the recently established N'gousso M form laboratory colony that retains much of the genetic variation of field mosquitoes, were antibiotic treated for 5 days and subsequently orally infected with the Db11-GFP strain of S. marcescens. Bacteria-fed mosquitoes were selected 2 days post infection, and, 3 days post infection, guts from bacteria-fed mosquitoes were dissected. Uninfected control mosquitoes were treated in the same way. Differential expression in the gut of S. marcescens infected mosquitoes, compared to uninfected controls, was identified by hybridizing labelled complementary RNA, derived from total RNA extracted from the respective gut pools, in customized Agilent 4x44k gene expression microarrays, comprising oligonucleotide probes encompassing all An. gambiae annotated genes of the AgamP3.6 release, with each probe represented in duplicate.
