title: Root herbivory: molecular analysis of the maize transcriptome upon infestation by Southern corn rootworm, Diabrotica undecimpunctata howardi.
abstract: While many studies have characterized changes to the transcriptome of plants attacked by shoot-eating insect pests, few have examined transcriptome-level effects of root pests. Maize (Zea mays) seedlings were subjected to infestation for approximately 2 weeks by the root herbivore southern corn rootworm (SCR) Diabrotica undecimpunctata howardi, and changes in transcript abundance within both roots and shoots were analyzed using a 57K element microarray. A total of 541 genes showed statistically significant changes in transcript abundance in infested roots, including genes encoding many pathogenesis-related proteins such as chitinases, proteinase inhibitors, peroxidases and β-1,3-glucanases. Several WRKY transcription factors--often associated with biotic responses--exhibited increased transcript abundance upon SCR feeding. Differentially expressed (DE) genes were also detected in shoots of infested vs control plants. Quantitative Reverse Transcriptase Polymerase Chain Reaction (RT-PCR) was used to confirm patterns of transcript abundance for several significant DE genes using an independent experiment with a 2-6 day period of SCR infestation. Because of the well-documented roles that jasmonic acid (JA) or salicylic acid (SA) play in herbivory responses, the effect of exogenous JA or SA application on transcript abundance corresponding to the same subset of SCR-responsive genes was assessed. The response of these genes at the level of transcript abundance to SA and JA differed between roots and shoots and also differed among the genes that were examined. These data suggested that SA- and JA-dependent and independent signals contributed to the transcriptome-level changes in maize roots and shoots in response to SCR infestation.
authors.affiliation: Invasive Insect Biocontrol and Behavior Laboratory, USDA-ARS, BARC-West, 10,300 Baltimore Avenue, Building 011A, Room 214, Beltsville, MD 20705, USA. susan.lawrence@ars.usda.gov
authors.forename: Susan D
authors.initials: SD
authors.lastname: Lawrence
authors.forename: Nicole G
authors.initials: NG
authors.lastname: Novak
authors.forename: Walid El
authors.initials: WE
authors.lastname: Kayal
authors.forename: Chelsea J-T
authors.initials: CJ
authors.lastname: Ju
authors.forename: Janice E K
authors.initials: JE
authors.lastname: Cooke
mesh_terms: D000818:Animals; D001517:Coleoptera / Q000502:physiology*; D003517:Cyclopentanes / Q000494:pharmacology; D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant / Q000235:genetics*; D060434:Herbivory; D007814:Larva; D020411:Oligonucleotide Array Sequence Analysis; D054883:Oxylipins / Q000494:pharmacology; D010935:Plant Diseases / Q000469:parasitology*; D010937:Plant Growth Regulators / Q000494:pharmacology; D018517:Plant Roots / Q000235:genetics* / Q000469:parasitology; D018520:Plant Shoots / Q000235:genetics / Q000469:parasitology; D018749:RNA, Plant / Q000235:genetics; D020156:Salicylic Acid / Q000494:pharmacology; D015398:Signal Transduction / Q000235:genetics; D059467:Transcriptome; D015854:Up-Regulation / Q000235:genetics; D003313:Zea mays / Q000235:genetics* / Q000469:parasitology
chemical_list: D003517:Cyclopentanes; D054883:Oxylipins; D010937:Plant Growth Regulators; D018749:RNA, Plant; C011006:jasmonic acid; D020156:Salicylic Acid