Project description:UV-B radiation regulates numerous morphogenic, biochemical and physiological responses in plants, and can stimulate some responses typically associated with other abiotic and biotic stimuli, including invertebrate herbivory. Removal of UV-B from the growing environment of various plant species has been found to increase their susceptibility to consumption by invertebrate pests, however, to date, little research has been conducted to investigate the effects of UV-B on crop susceptibility to field pests. Here, we report findings from a multi-omic and genetic-based study investigating the mechanisms of UV-B-stimulated resistance of the crop, Brassica napus (oilseed rape), to herbivory from an economically important lepidopteran specialist of the Brassicaceae, Plutella xylostella (diamondback moth). The UV-B photoreceptor, UV RESISTANCE LOCUS 8 (UVR8), was not found to mediate resistance to this pest. RNA-Seq and untargeted metabolomics identified components of the sinapate/lignin biosynthetic pathway that were similarly regulated by UV-B and herbivory. Arabidopsis mutants in genes encoding two enzymes in the sinapate/lignin biosynthetic pathway, CAFFEATE O-METHYLTRANSFERASE 1 (COMT1) and ELICITOR-ACTIVATED GENE 3-2 (ELI3-2), retained UV-B-mediated resistance to P. xylostella herbivory. However, overexpression of B. napus COMT1 in Arabidopsis further reduced plant susceptibility to P. xylostella herbivory in a UV-B-dependent manner. These findings demonstrate that overexpression of a component of the sinapate/lignin biosynthetic pathway in a member of the Brassicaceae can enhance UV-B-stimulated resistance to herbivory from P. xylostella.
Project description:Plants are attacked by diverse herbivores and respond with manifold defense responses. To study transcriptional and other early regulation events of these plant responses, herbivory is often mimicked to standardize the temporal and spatial dynamics that vary tremendously for natural herbivory. Yet to what extent such mimics of herbivory are able to elicit the same plant response as real herbivory remains largely undetermined. We examined the transcriptional response of a new model plant to herbivory by a lepidopteran larva and to a commonly used herbivory mimic by applying the larvae’s oral secretions to standardized wounds. We designed a microarray for Solanum dulcamara and showed that the transcriptional response to real and to simulated herbivory by Spodoptera exigua overlapped moderately by about 40%. Interestingly, certain responses were mimicked better than others; 60% of the genes up-regulated but not even a quarter of the genes down-regulated by herbivory were similarly affected by application of oral secretions to wounds. While the regulation of genes involved in signaling, defense and water stress were mirrored well by the herbivory mimic, most of the genes related to photosynthesis, carbohydrate- and lipid metabolism were exclusively regulated by real herbivory. Thus, wounding and elicitor application decently mimics herbivory-induced defense responses but likely not the re-allocation of primary metabolites induced by real herbivory.
Project description:Maize plants were subjected to foliar herbivory and both whorl and root tissue were collected at 0 h and 24 h. microarray was performed to compare transcriptional profiles and interpret the signaling molecules mediating systemic responses
Project description:Tomato plants are submitted to a high diversity of herbivory pests, among them the leafminer Tuta absoluta, considered as one of the most important threat on the tomato worldwide production. In spite of its susceptibility to this pest, a better understanding of the tomato plant response to T. absoluta herbivory will help defining plant resistance traits and enlarging the range of possibilities for an efficient integrated pest management strategy. We analyzed the transcriptomic response in leaves of tomato (cv. Better Bush) submitted to the herbivory of T. absoluta larvae after 5h and 24h.
Project description:In this experiment we aimed to decipher the transcription response of rice to the different cues of an herbivory attack from the chewing caterpillar Spodoptera frugiperda. We performed a herbivory mimic procedure on seedlings and applied mechanical wounding (WOS), application of herbivore oral secretions (OS) after wounding (WOS+) and dysbiotic OS (WOS-) on rice leaves. RNA was extracted from control and treated leaves after two hours. 5 biological replicates corresponding to 5 pooled leaves were performed for each of the four condition
Project description:Priming of plant defenses provides increased plant protection against herbivores and reduces the allocation costs of defense. Defense priming in woody plants remains obscure, in particular due to plant development traits such as the endogenous rhythmic growth displayed by oaks (Quercus robur). By using bioassays with oak microcuttings, and by combining transcriptomic and metabolomic analyses, we investigated how leaf herbivory by Lymantria dispar and root inoculation with the ectomycorrhizal fungus Piloderma croceum prime oak defenses. We further investigated how defense priming is modulated by rhythmic growth of the oaks. A first herbivory challenge in oak leaves primed newly grown leaves for an enhanced induction of jamonic acid (JA)-related direct defenses, or enhanced emission of volatiles, depending on the specific growth stage at which the plants where challenged. Root inoculation with Piloderma abolished the enhanced induction of JA-related defenses and volatile emission. Our results indicate that a first herbivore attack primes direct and indirect defenses of newly formed oak leaves, and that the specific display of defense priming is modulated by rhythmic growth. Our results further show that the priming memory in oaks can be transmitted to the next growth cycle even to the leaves of the new shoot unit.
Project description:<p>UV-B radiation regulates numerous morphogenic, biochemical and physiological responses in plants, and can stimulate some responses typically associated with other abiotic and biotic stimuli, including invertebrate herbivory. Removal of UV-B from the growing environment of various plant species has been found to increase their susceptibility to consumption by invertebrate pests, however, to date, little research has been conducted to investigate the effects of UV-B on crop susceptibility to field pests. Here, we report findings from a multi-omic and genetic-based study investigating the mechanisms of UV-B-stimulated resistance of the crop, <em>Brassica napus</em> (oilseed rape), to herbivory from an economically important lepidopteran specialist of the <em>Brassicaceae</em>, <em>Plutella xylostella</em> (diamondback moth). The UV-B photoreceptor, UV RESISTANCE LOCUS 8 (UVR8), was not found to mediate resistance to this pest. RNA-Seq and untargeted metabolomics identified components of the sinapate/lignin biosynthetic pathway that were similarly regulated by UV-B and herbivory. Arabidopsis mutants in genes encoding two enzymes in the sinapate/lignin biosynthetic pathway, CAFFEATE O-METHYLTRANSFERASE 1 (COMT1) and ELICITOR-ACTIVATED GENE 3-2 (ELI3-2), retained UV-B-mediated resistance to <em>P. xylostella</em> herbivory. However, the overexpression of <em>B. napus</em> COMT1 in <em>Arabidopsis</em> further reduced plant susceptibility to <em>P. xylostella</em> herbivory in a UV-B-dependent manner. These findings demonstrate that overexpression of a component of the sinapate/lignin biosynthetic pathway in a member of the <em>Brassicaceae</em> can enhance UV-B-stimulated resistance to herbivory from <em>P. xylostella</em>.</p>
Project description:Cereal aphids can successfully colonize and damage switchgrass (Panicum virgatum) plants. Among the aphids tested, greenbugs (Schizaphis graminum, GB) caused significant plant damage likely through a combination of aphid-salivary proteins that are injected into plants during feeding and a strong host response elicited by herbivory. In this study, changes in protein phosphorylation present in GB-infested and uninfested control plants was determined. These data were compared against transcriptome changes recently published for this system.
Project description:The expression of stress-related genes induced by feeding of chestnut moth larvae (Conistra vaccinii L.) was studied with Vitreoscilla hemoglobin-expressing (VHb) and non-transgenic hybrid aspen lines (Populus tremula x P. tremuloides). Besides the herbivore-injured leaves (L1), cDNA microarray analyses were conducted using uninjured leaves of hybrid aspen lines positioned above (A) and below (B) the herbivory exposed leaves. Two-condition experiment, control vs. herbivory exposure. Two hybrid aspen lines: non-transgenic V617 and VHb expressing V617 /45. Of each plant, three leaf types were analysed: the injured/uninjured leaf (L1) and nonorthostichous leaf positioned above (A) and below (B). Biological replicates: 3. On each array, two samples representing L1, A or B leaf type of control and herbivory treatment of either V617 or V617/45 line. line V617: wt_A_rep1-3, wt_B_rep1-3, wt_L1_rep1-3 line V617/45: VHb_A_rep1-3, VHb_B_rep1-3, VHb_L1_rep1-3 leaf type A: wt_A_rep1-3, VHb_A_rep1-3 leaf type B: wt_B_rep1-3, VHb_B_rep1-4 leaf type L1: wt_L1_rep1-3, VHb_L1_rep1-5
Project description:In plants, an increase in resource allocation to growth (primary metabolism) associated with the presence of neighbors is likely to reduce defense-related production (secondary metabolism), making plants more vulnerable to herbivory. Even though there is increasing evidence supporting this “trade-off hypothesis”, the underlying mechanisms are still unclear. Far red (FR) radiation reflected from plant tissues serves as an early warning signal of future competition, triggering a suite of plastic morphological adjustments that improve plant’s ability to compete for light in crowded populations. Recent evidence from our lab showed that, when competition signals are present, plant defenses are severely reduced. Besides direct effects of herbivory and competition signals on target plants, second order effects occurs on neighboring plants through plant volatiles (PVs) communication. PVs play a key role in plant-plant and plant-insect interactions, changing its content and composition in response to environmental conditions. To increase our understanding of the molecular mechanisms underlying those interacting signaling webs, we performed a field study with tomato plants (cv Moneymaker), in which plants of EMITTER plots (six plants plot-1) were subjected to herbivory (nine larvae of Spodoptera eridania plant-1) and competition signals (increased FR radiation) in a factorial design. Light treatment started 28 days after sowing (DAS), and herbivory treatment and volatiles conduction started 34 DAS. Volatiles were conducted from EMITTER to RECEIVER plots (five plants plot-1) using a 5 inch, 1.4 m long tube fitted with a computer-type fan. 40 and 45 DAS, larval performance was measured on EMITTER plots as well as naturally-occurring insect colonization on RECEIVER plots. Finally (46 DAS), samples for bulk phenolic content were taken on every plot, and plant material from 4th and 5th leaves was collected for microarray analysis. There were three real biological replicates. Keywords: Reference design