title: The Transcriptome and Terpene Profile of Eucalyptus grandis Reveals Mechanisms of Defense Against the Insect Pest, Leptocybe invasa.
abstract: Plants have evolved complex defenses that allow them to protect themselves against pests and pathogens. However, there is relatively little information regarding the Eucalyptus defensome. Leptocybe invasa is one of the most damaging pests in global Eucalyptus forestry, and essentially nothing is known regarding the molecular mechanisms governing the interaction between the pest and host. The aim of the study was to investigate changes in the transcriptional landscape and terpene profile of a resistant and susceptible Eucalyptus genotype in an effort to improve our understanding of this interaction. We used RNA-seqencing to investigate transcriptional changes following L. invasa oviposition. Expression levels were validated using real-time quantitative PCR. Terpene profiles were investigated using gas chromatography coupled to mass spectometry on uninfested and oviposited leaves. We found 698 and 1,115 significantly differentially expressed genes from the resistant and susceptible interactions, respectively. Gene Ontology enrichment and Mapman analyses identified putative defense mechanisms including cell wall reinforcement, protease inhibitors, cell cycle suppression and regulatory hormone signaling pathways. There were significant differences in the mono- and sesquiterpene profiles between genotypes and between control and infested material. A model of the interaction between Eucalyptus and L. invasa was proposed from the transcriptomic and chemical data.
authors.affiliation: Department of Genetics, Forestry and Agricultural Biotechnology Institute (FABI), Genomics Research Institute (GRI), University of Pretoria, Private bag x20, Pretoria, 0028, South Africa.
authors.forename: Caryn N
authors.initials: CN
authors.lastname: Oates
authors.affiliation: Research School of Biology, Australian National University, 116 Daley Rd, Canberra, 0200, ACT, Australia.
authors.forename: Carsten
authors.initials: C
authors.lastname: Külheim
authors.affiliation: Department of Genetics, Forestry and Agricultural Biotechnology Institute (FABI), Genomics Research Institute (GRI), University of Pretoria, Private bag x20, Pretoria, 0028, South Africa.
authors.forename: Alexander A
authors.initials: AA
authors.lastname: Myburg
authors.affiliation: Department of Genetics, Forestry and Agricultural Biotechnology Institute (FABI), Genomics Research Institute (GRI), University of Pretoria, Private bag x20, Pretoria, 0028, South Africa.
authors.forename: Bernard
authors.initials: B
authors.lastname: Slippers
authors.affiliation: Department of Genetics, Forestry and Agricultural Biotechnology Institute (FABI), Genomics Research Institute (GRI), University of Pretoria, Private bag x20, Pretoria, 0028, South Africa Sanushka.Naidoo@up.ac.za.
authors.forename: Sanushka
authors.initials: S
authors.lastname: Naidoo
mesh_terms: D000818:Animals; D060467:Disease Resistance / Q000235:genetics; D005052:Eucalyptus / Q000235:genetics* / Q000378:metabolism / Q000469:parasitology; D005260:Female; D008401:Gas Chromatography-Mass Spectrometry; D018506:Gene Expression Regulation, Plant; D063990:Gene Ontology; D005838:Genotype; D006790:Host-Parasite Interactions; D055442:Metabolome / Q000235:genetics; D008957:Models, Genetic; D010058:Oviposition; D010935:Plant Diseases / Q000235:genetics / Q000469:parasitology; D018515:Plant Leaves / Q000235:genetics / Q000378:metabolism / Q000469:parasitology; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013729:Terpenes / Q000378:metabolism*; D059467:Transcriptome / Q000235:genetics*; D014863:Wasps / Q000033:anatomy & histology* / Q000502:physiology
chemical_list: D010940:Plant Proteins; D013729:Terpenes
keywords: Defence response; Eucalyptus; Leptocybe invasa; RNA-Seq; Terpene profile