Tsetse Immune System Maturation Requires the Presence of Obligate Symbionts in Larvae

• DOI: 10.1371/journal.pbio.1000619
• Publication Date: 2011-05-31T20:48:56Z
• Authors: Brian L. Weiss; Jingwen Wang; Serap Aksoy
• Keywords: Obligate; Prophenoloxidase

Beneficial microbial symbionts serve important functions within their hosts, including dietary supplementation and maintenance of immune system homeostasis. Little is known about the mechanisms that enable these bacteria to induce specific host phenotypes during development into adulthood. Here we used tsetse fly, Glossina morsitans, its obligate mutualist, Wigglesworthia glossinidia, investigate co-evolutionary adaptations influence physiological processes. maternally transmitted tsetse's intrauterine larvae through milk gland secretions. We can produce flies lack (GmmWgm−) yet retain other symbiotic microbes. Such offspring give rise adults exhibit a largely normal phenotype, with exception being they are reproductively sterile. Our results indicate when reared under environmental conditions GmmWgm− also immuno-compromised highly susceptible hemocoelic E. coli infections while age-matched wild-type individuals refractory. Adults larval exceptionally compromised cellular humoral responses following challenge, reduced expression genes encode antimicrobial peptides (cecropin attacin), hemocyte-mediated processes (thioester-containing proteins 2 4 prophenoloxidase), signal-mediating molecules (inducible nitric oxide synthase). Furthermore, harbor population sessile circulating hemocytes, phenomenon likely from significant decrease in serpent lozenge, both which associated process early hemocyte differentiation. demonstrate must be present immature progeny order for function properly adult tsetse. This provides evidence another adaptation further anchors symbiosis between Wigglesworthia.