Friday, October 5, 2018 at 12:00pm to 1:00pm
Ray R. Irani, RRI 101 1050 Childs Way Los Angeles, CA 90089
"To Give or to Take: Bacterial Regulation of Conflicting Symbiotic Behaviors with Invertebrates"
Abstract: Entomopathogenic Steinernema nematodes employ Xenorhabdus bacteria symbionts to help kill insects and to support reproduction within the cadaver. Infective nematodes release their bacterial symbiont into the insect hemocoel, where the two allies face and overcome insect immunity. The bacterial symbiont then provides activities that support nematode reproduction through bioconversion of the insect cadaver. Nutrient depletion triggers development of the nematode into its colonized infective form to begin the cycle anew. Virulence and immune suppression have been investigated using X. nematophila bacteria, the symbiont of S. carpocapsae nematodes, infecting lepidopteran insects (e.g. Manduca sexta). The mutualistic and pathogenic behaviors of X. nematophila symbionts are regulated by the transcription factor Lrp, which regulates the expression of many genes. I will discuss how this regulation helps coordinate expression of symbiotic traits during the Xenorhabdus-Steinernema life cycle.