Genetic analysis of defense related genes in switchgrass during greenbug aphid (Schizaphis graminum (Rondani)) infestation

Plants infested with insects induce a variety of defense strategies to limited pathogen feeding and associated disease.  Despite recent advancements in understanding plant defense systems, little is known about the molecular mechanisms of disease induction and progression in agriculturally significant grasses during insect attack.  Here we performed a next-generation sequencing study to analyze global gene expression changes associated with disease development in Panicum virgatum, switchgrass, infested with the greenbugs aphids (Schizaphis graminum (Rondani)) throughout a 15 day time course.  Distinct expression patterns were found to be significantly altered during greenbug feeding which coincide with disease symptoms development and associated cell death. We identified multiple transcription factors, oxidative enzymes, terpenes and herbivore/pest resistance protein transcripts that showed induction at unique time points as well as many that were induced throughout the infestation. This study provides the first comprehensive look using RNA-seq to explore host defense strategies employed by switchgrass to defend itself against greenbugs throughout a time course.