03656nas a2200337 4500008004100000245005700041210005600098260004900154490001000203520257600213653001802789653002302807653003202830653003002862653001602892653002402908653003402932653002402966653002402990653002003014653005103034653002403085653001803109653002003127653003003147653002403177653003003201100002503231700001703256856004503273 2010 eng d00aGenomic analysis of nematode-environment interaction0 aGenomic analysis of nematodeenvironment interaction aProvo, UTbBrigham Young Universityc08/20100 vPh.D.3 a

The natural environments of organisms present a multitude of biotic and abiotic challenges that require both short-term ecological and long-term evolutionary responses. Though most environmental response studies have focused on effects at the ecosystem, community and organismal levels, the ultimate controls of these responses are located in the genome of the organism. Soil nematodes are highly responsive to, and display a wide variety of responses to changing environmental conditions, making them ideal models for the study of organismal interactions with their environment. In an attempt to examine responses to environmental stress (desiccation and freezing), genomic level analyses of gene expression during anhydrobiosis of the Antarctic nematode Plectus murrayi was undertaken. An EST library representative of the desiccation induced transcripts was established and the transcripts differentially expressed during desiccation stress were identified. The expressed genome of P. murrayi showed that desiccation survival in nematodes involves differential expression of a suite of genes from diverse functional areas, and constitutive expression of a number of stress related genes. My study also revealed that exposure to slow desiccation and freezing plays an important role in the transcription of stress related genes, improves desiccation and freezing survival of nematodes. Deterioration of traits essential for biological control has been recognized in diverse biological control agents including insect pathogenic nematodes. I studied the genetic mechanisms behind such deterioration using expression profiling. My results showed that trait deterioration of insect pathogenic nematode induces substantial overall changes in the nematode transcriptome and exhibits a general pattern of metabolic shift causing massive changes in metabolic and other processes. Finally, through field observations and molecular laboratory experiments the validity of the growth rate hypothesis in natural populations of Antarctic nematodes was tested. My results indicated that elemental stoichiometry influences evolutionary adaptations in gene expression and genome evolution. My study, in addition to providing immediate insight into the mechanisms by which multicellular animals respond to their environment, is transformative in its potential to inform other fundamental ecological and evolutionary questions, such as the evolution of life-history patterns and the relationship between community structure and ecological function in ecosystems.

10aanhydrobiosis10aAntarctic nematode10acomparative transcriptomics10acomplementary DNA library10adesiccation10afunctional analysis10aHeterorhabditis bacteriophora10aMcMurdo Dry Valleys10amicroarray analysis10aPlectus murrayi10aquantative real-time polymerase chain reaction10aScottnema lindsayae10astoichiometry10astress survival10asubtractive hybridization10atrait deterioration10atranscriptional profiling1 aAdhikari, Bishwo, N.1 aAdams, Byron uhttps://scholarsarchive.byu.edu/etd/2578