Mapping Quantitative Trait Loci Involved in Caenorhabditis elegans Response to Soil Bacteria

Z. Wang, M.A. Herman, L.B. Snoek, J.E. Kammenga

Research output: Chapter in Book/Report/Conference proceedingAbstract

Abstract

Nematodes, the most abundant metazoans on earth, are responsive to both biotic and abiotic environmental stimuli. Thus, they have great potential to serve as indicators of environmental change. Soil bacteria are an important part of the biotic environment for bacterial feeding soil nematodes, serving not only as food sources but can also potential pathogens. Interactions between nematodes and bacteria, therefore, are of significant importance to understand the ecological dynamics of the soil community. In order to dissect this complexity, we are using C. elegans to model the interactions of native soil nematodes with soil bacteria and have identified C. elegans genes responsive to various soil bacteria. To identify the genetic variation underlying C. elegans response to different bacteria we have taken quantitative genetic approach and mapped Quantitative Trait Loci (QTL) in a N2×CB4856 recombinant inbred panel in response to E. coli OP50, the strain used as standard lab food for C. elegans and Stenotrophomonas maltophilia, a ubiquitous soil bacterium that we isolated in association with native nematodes Oscheius sp., Pelodera sp., Mesorhabditis sp., and Plectus sp. from grassland soils. S. maltophilia can also cause difficult to treat nosocomial infections in human, especially immuno-compromised individuals. It has been shown that the DAF-2/insulin-like receptor is a negative regulator of C. elegans innate immunity and longevity pathways. As a result, daf-2 mutants are long-lived and resistant to all bacteria tested to date. Surprisingly, we have observed that lifespan of both wild type and daf-2 mutant animals are significantly reduced when grown on S. maltophilia. Hence study of genetic basis in response to S. maltophilia might also identify novel genes involved in innate immunity pathways. We have mapped traits for the C. elegans response to E. coli and S. maltophilia as well as the plastic response to six QTL with various strengths on LGI, IV and X. Three of these are plasticity QTL. Phenotypic plasticity is the ability of an organism to have varied phenotypes in response to different environments. Our results support a genetic basis for plasticity, which would help provide insights to understanding the evolution of interactions between soil nematodes and bacteria in their natural environment. We have used near isogenic lines to refine the position of one of the plasticity QTL to a 639kb segment of LGX. There are 135 genes within this interval and we selected those as candidate genes that bear single nucleotide polymorphisms that cause amino acid replacement that would change the biochemical characteristics of the putative product. These candidate genes will then be subjected to functional analysis to determine how they are involved in the phenotypic plasticity of the C. elegans response to E. coli and S. maltophilia
Original languageEnglish
Title of host publicationPoster abstracts of the Ecological Genomics Symposium: Genes in Ecology. Ecology in Genes, November 13-15, 2009, Kansas, USA
Place of PublicationKansas City
Pages28 (53)
Publication statusPublished - 2009
EventEcological Genomics Symposium, Kansas, USA -
Duration: 13 Nov 200915 Nov 2009

Conference

ConferenceEcological Genomics Symposium, Kansas, USA
Period13/11/0915/11/09

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