Molecular Interactions between the Specialist HerbivoreManduca sexta (Lepidoptera, Sphingidae) and Its Natural Host Nicotiana attenuata. I. Large-Scale Changes in the Accumulation of Growth- and Defense-Related Plant mRNAs

Abstract

Plants respond to herbivore attack with a dramatic functional reorganization that involves the activation of direct and indirect defenses and tolerance, which in turn make large demands on primary metabolism. Here we provide the first characterization of the transcriptional reorganization that occurs after insect attack in a model plant-herbivore system: Nicotiana attenuata Torr. ex Wats.-Manduca sexta. We used mRNA differential display to characterize one-twentieth of the insect-responsive transcriptome of N. attenuata and verified differential expression for 27 cDNAs. Northern analyses were used to study the effects of folivory and exposure to airborne methyl jasmonate and for kinetic analyses throughout a 16-hlight/8-h-dark cycle. Sequence similarity searches allowed putative functions to be assigned to 15 transcripts. Genes were related to photosynthesis, electron transport, cytoskeleton, carbon and nitrogen metabolism, signaling, and a group responding to stress, wounding, or invasion of pathogens. Overall, transcripts involved in photosynthesis were strongly down-regulated, whereas those responding to stress, wounding, and pathogens and involved in shifting carbon and nitrogen to defense were strongly up-regulated. The majority of transcripts responded similarly to airborne methyl jasmonate and folivory, and had tissue-and diurnal-specific patterns of expression. Transcripts encoding Thr deaminase (TD) and a putative retrotransposon were absent in control plants, but were strongly induced after herbivory. Full-length sequences were obtained for TD and the pathogen-inducible ␣-dioxygenase, PIOX. Effects of abiotic and biotic stimuli were investigated for transcripts encoding TD, importin ␣, PIOX, and a GAL83-like kinase cofactor.

Herbivore-induced defence response in the brown seaweedFucus vesiculosus(Phaeophyceae): temporal pattern and gene expression

“…For example, several functional groups of genes related to the basal metabolism of F. vesiculosus showed a considerable change in expression between day 15 and day 18 (KOG categories 'Metabolism', 'Energy production and conversion', 'Translation, ribosomal structure and biogenesis' and 'Transcription'). It is known that the induction of plant anti-herbivory defences requires functional reorganization that also involves primary metabolic processes, since increased requirements for energy, reducing equivalents and precursors have to be covered by these processes (Hermsmeier et al, 2001). Fatty acid metabolism was up-regulated, including several genes involved in fatty acid degradation (Fig.…”

Transcriptional Regulation of Sorghum Defense Determinants against a Phloem-Feeding Aphid

“…Suppression of photosynthesis by JA has been established (Creelman and Mullet, 1997), and an inverse correlation between photosynthesisand defense-related gene regulation has also been observed in plants subjected to fungal infection, elicitor treatment, or insect herbivory (Kombrink and Hahlbrock, 1990;Hermsmeier et al, 2001). This response presumably allows energy reallocation to defense responses, with suppression of less important functions, upon attack by insects and pathogens.…”

A Plasma Membrane Protein from Zea mays Binds with the Herbivore Elicitor Volicitin

“…Most recently, microarray studies that have compared mRNA levels in mechanically wounded and caterpillar-wounded plants have revealed very different transcript profiles. In Arabidopsis thaliana, insect wounding resulted in a downregulation of water stress-induced genes compared with wounding alone (Reymond et al, 2000), whereas in Nicotiana tabacum (tobacco), wound-induced transcripts are modified by insect regurgitant either by suppressing wound-induced transcripts systemically or by amplifying the wound response in the attacked leaves (Hermsmeier et al, 2001).…”