RESUMEN
Fundamental to holobiont biology is recognising how variation in microbial composition and function relates to host phenotypic variation. Sponges often exhibit considerable phenotypic plasticity and also harbour dense microbial communities that function to protect and nourish hosts. One of the most prominent sponge genera on Caribbean coral reefs is Agelas. Using a comprehensive set of morphological (growth form, spicule), chemical and molecular data on 13 recognised species of Agelas in the Caribbean basin, we were able to define only five species (=clades) and found that many morphospecies designations were incongruent with phylogenomic and population genetic analyses. Microbial communities were also strongly differentiated between phylogenetic species, showing little evidence of cryptic divergence and relatively low correlation with morphospecies assignment. Metagenomic analyses also showed strong correspondence to phylogenetic species, and to a lesser extent, geographical and morphological characters. Surprisingly, the variation in secondary metabolites produced by sponge holobionts was explained by geography and morphospecies assignment, in addition to phylogenetic species, and covaried significantly with a subset of microbial symbionts. Spicule characteristics were highly plastic, under greater impact from geographical location than phylogeny. Our results suggest that while phenotypic plasticity is rampant in Agelas, morphological differences within phylogenetic species affect functionally important ecological traits, including the composition of the symbiotic microbial communities and metabolomic profiles.
Asunto(s)
Agelas , Poríferos , Animales , Filogenia , Región del Caribe , Indias Occidentales , Arrecifes de Coral , Poríferos/genéticaRESUMEN
Studies of natural rotavirus (RV) infection in children have shown that protection against subsequent RV disease occurs (1). Assessment of humoral immune responses has included study of the importance of circulating vs intestinal antibodies (Abs), serotype-specific vs group-specific Abs, and RV-specific immunoglobulins IgA, IgM, and IgG (1). Following natural RV infection, RV-specific IgM, followed by IgA and IgG, appear in serum and duodenal fluid or stool of young children (2). Protection against subsequent RV infection is predicted by the quantity of virus-specific IgA in the feces and serum (3, 4). In addition, virus-specific antibody-secreting cells (ASC) of the IgA, IgM, and IgG isotypes have been detected in the blood of infants following RV infection (5), although correlation between the presence of ASCs and protection against subsequent disease has not been studied. Serum neutralizing antibodies (nAbs) occur after natural RV infection in children, and are serotype-specific (4,6). Overall, protection against subsequent RV infection is correlated with higher titers of nAb (4). Protection against infection has been correlated with homotypic nAb to the G1 serotype (4); however, other studies suggest that protection is not dependent on serotype-specific nAb (7).