Author:

Keywords:

Animals, Arabidopsis, Biological Assay, Butterflies, Cyclopentanes, Gene Expression Profiling, Gene Expression Regulation, Plant, Herbivory, Larva, Mouth, Oligonucleotide Array Sequence Analysis, Oxylipins, Plant Leaves, RNA, Plant, Salicylic Acid, Signal Transduction, Spodoptera, Stress, Physiological, Suppression, Genetic, Transcriptome, Science & Technology, Life Sciences & Biomedicine, Plant Sciences, Arabidopsis thaliana, defence suppression, gene expression, insect oral secretions, wounding, HERBIVORE MANDUCA-SEXTA, HOST NICOTIANA-ATTENUATA, FEEDING SPODOPTERA-LITTORALIS, LIMA-BEAN LEAVES, PLANT VOLATILES, GENE-EXPRESSION, MOLECULAR-INTERACTIONS, DEFENSE RESPONSES, DIFFERENTIAL INDUCTION, GENERALIST HERBIVORE, 0604 Genetics, 0607 Plant Biology, 0703 Crop and Pasture Production, Plant Biology & Botany, 3004 Crop and pasture production, 3101 Biochemistry and cell biology, 3108 Plant biology

Abstract:

The induction of plant defences and their subsequent suppression by insects is thought to be an important factor in the evolutionary arms race between plants and herbivores. Although insect oral secretions (OS) contain elicitors that trigger plant immunity, little is known about the suppressors of plant defences. The Arabidopsis thaliana transcriptome was analysed in response to wounding and OS treatment. The expression of several wound-inducible genes was suppressed after the application of OS from two lepidopteran herbivores, Pieris brassicae and Spodoptera littoralis. This inhibition was correlated with enhanced S. littoralis larval growth, pointing to an effective role of insect OS in suppressing plant defences. Two genes, an ERF/AP2 transcription factor and a proteinase inhibitor, were then studied in more detail. OS-induced suppression lasted for at least 48 h, was independent of the jasmonate or salicylate pathways, and was not due to known elicitors. Interestingly, insect OS attenuated leaf water loss, suggesting that insects have evolved mechanisms to interfere with the induction of water-stress-related defences.