Conifer defence against insects: microarray gene expression profiling of Sitka spruce (Picea sitchensis) induced by mechanical wounding or feeding by spruce budworms (Choristoneura occidentalis) or white pine weevils (Pissodes strobi) reveals large

摘要: Conifers are resistant to attack from a large number of potential herbivores or pathogens. Previous molecular and biochemical characterization selected conifer defence systems support model multigenic, constitutive induced defences that act on invading insects via physical, chemical, ecological (multitrophic) mechanisms. However, the genomic foundation complex resistance mechanisms conifers is largely unknown. As part genomics strategy characterize inducible possible against insect herbivory, we developed cDNA microarray building upon new spruce (Picea spp.) expressed sequence tag resource. This first-generation contains 9720 elements representing c. 5500 unique genes. We used this array monitor gene expression in Sitka sitchensis) bark response herbivory by white pine weevils (Pissodes strobi, Curculionidae) wounding, young shoot tips western budworm (Choristoneura occidentalis, Lepidopterae) feeding. Weevils stem-boring feed phloem, while budworms foliage feeding larvae consume needles tips. Both species wounding treatment caused substantial changes host plant transcriptome detected each case differential several thousand at 1 2 d after onset treatment. Overall, there was considerable overlap among differentially sets these three stress treatments. Functional classification transcripts revealed genes with roles general defence, octadecanoid ethylene signalling, transport, secondary metabolism, transcriptional regulation. Several involved primary metabolic processes such as photosynthesis were down-regulated fitting concept dynamic resource allocation defence. Refined analysis using gene-specific primers real-time PCR for agreement results most tested. study provides first large-scale survey insect-induced gymnosperm platform functional investigation plant-insect interactions spruce. Induction terpenoid biosynthesis, phenolic metabolism discussed more detail.