Project description:To investigate the impact of a plant´s response to abiotic stress on plant defense against subsequent biotic stress, we determined the transcriptional response of Arabidopsis thaliana to low temperature stress (4°C) and subsequent mechanical wounding or larval feeding damage by the herbivores Mamestra brassicae (generalist) and Pieris brassicae (specialist). In total, 21%, 4% and 14% of all genes responsive to M. brassicae, P. brassicae or mechanical wounding were differentially regulated in previously cold-treated compared to untreated plants.
Project description:Low reduced red:far-red ratio [R:FR] signaling through phytochromes induces shade avoidance responses, including petiole elongation. Jasmonic acid-mediated defense against herbivores and pathogens is inhibited under these conditions. Using microarrays we studied the crosstalk between low R:FR and JA at the global gene expression level in Arabidopsis thaliana. Plants were exposed for 2 h. to the following treatments: high R/FR with mock spray, low R/FR with mock spray, high R/FR with JA spray, low R/FR with JA spray. Gene expression was determined in petioles.
Project description:Plants can prepare their defense of impending herbivory, when they previously perceived eggs deposited by herbivores insect which reliably indicates that larvae will soon hatch and feed on the plants. Using Arabidopsis thaliana and Pieris brassicae we addressed the question whether prior egg deposition affects transcriptional changes in feeding-damaged plants. We determined the transcriptomes of Arabidopsis leaves that (i) were for six days deposited with eggs and suffered larval feeding for two days, (ii) suffered larval feeding for two days without prior egg deposition or (iii) were left untreated.
Project description:Soybean is one of the main sources of oil worldwide, and the cotton bollworm [Helicoverpa armigera (Hübner)] is one of the common herbivores seriously affecting soybean production. After being attacked by herbivores, multiple signaling patheways will be triggered in plants, which induces the production of toxic, repellent, or anti-digestive compounds. Genetic engineering and breeding of resistant plant lines are the most effective and environmentally friendly approaches to control herbivores and improve the performance of plants. This study focuses on founding changes genes and proteins in soybean defense response induced by H. armigera. Illumina Solexa sequencing platform and iTRAQ were used for the comparative analysis of transcriptome and proteome profiles in the leaves of Tianlong 2 (a cultivated soybean susceptible to herbivores) and ED059 (a wild soybean resistant to herbivores) in response to infestation by H. armigera. Transcriptome data show that 2073 differentially expressed genes (DEGs) were uniquely expressed in ED059 compared with those in Tianlong 2 after 24 h of H. armigera treatment. Based on gene ontology classification of these 2073 DEGs, we identified 233 DEGs corresponded to various signaling pathways, including protein kinases, transcriptional factors, hormone biosynthesis and signal transduction pathways. In addition, a large number of genes related to antinutritive or toxic proteins were special induced in ED059. By combining the gene expression at the transcriptomic and proteomic levels, results reveal that no significantly high correlation was detected between the expression of mRNAs and proteins. Functional analysis of three candidate genes was accomplished by Agrobacterium-mediated transformation in Arabidopsis thaliana, and a MYB transcription factor 109 (MYB109) was identified with herbivore defense function in ED059. This study provides insights into the identification of the potential genes and proteins involved in herbivore defense, and a possible understanding of the herbivore defense mechanism in a wild soybean by combining analysis of transcriptome and proteome data. Moreover, a novel gene associated with herbivore resistance function was identified and validated.
Project description:Loliolide, a metabolite of carotenoid metabolic pathways in plants, was identified as an inducer of resistance to herbivores such as the two-spotted spider mite, Tetranychus urticae, and the common cutworm, Spodoptera litura. To identify host factors involved in loliolide-induced herbivore resistance, microarray analysis of tomato plants treated with loliolide was performed. We identified several cell wall-associated defense genes as loliolide-responsive genes.
Project description:NaJAZh regulates a subset of defense responses against herbivores and counteracts developmental necrosis in Nicotiana attenuata plants
Project description:Plant resistance traits against insect herbivores are extremely plastic. Plants respond not only to the herbivory itself, but also to oviposition by herbivorous insects. How prior oviposition affects plant responses to larval herbivory is largely unknown. Combining bioassays and defense protein activity assays with microarray analyses and metabolite profiling, we investigated the impact of preceding oviposition on the interaction of Solanum dulcamara with the generalist lepidopteran herbivore Spodoptera exigua at the levels of the plant's resistance, transcriptome and metabolome. We found that oviposition increased plant resistance to the subsequently feeding larvae. While constitutive and feeding-induced levels of defensive protease inhibitor activity remained unaffected, pre-exposure to eggs altered S. dulcamara's transcriptional and metabolic response to larval feeding in leaves local and systemic to oviposition. Particularly, genes involved in phenylpropanoid metabolism were stronger expressed in previously oviposited plants, which was reflected by reciprocal changes of primary metabolites upstream and within these pathways. Our data highlight that plants integrate signals from non-threatening life stages of their natural enemies to optimize their response when they become actually attacked. The observed transcriptional and metabolic reshaping of S. dulcamara's response to S. exigua herbivory suggests a role of phenylpropanoids in oviposition-primed plant resistance.
Project description:Plant resistance traits against insect herbivores are extremely plastic. Plants respond not only to the herbivory itself, but also to oviposition by herbivorous insects. How prior oviposition affects plant responses to larval herbivory is largely unknown. Combining bioassays and defense protein activity assays with microarray analyses and metabolite profiling, we investigated the impact of preceding oviposition on the interaction of Solanum dulcamara with the generalist lepidopteran herbivore Spodoptera exigua at the levels of the plant's resistance, transcriptome and metabolome. We found that oviposition increased plant resistance to the subsequently feeding larvae. While constitutive and feeding-induced levels of defensive protease inhibitor activity remained unaffected, pre-exposure to eggs altered S. dulcamara's transcriptional and metabolic response to larval feeding in leaves local and systemic to oviposition. Particularly, genes involved in phenylpropanoid metabolism were stronger expressed in previously oviposited plants, which was reflected by reciprocal changes of primary metabolites upstream and within these pathways. Our data highlight that plants integrate signals from non-threatening life stages of their natural enemies to optimize their response when they become actually attacked. The observed transcriptional and metabolic reshaping of S. dulcamara's response to S. exigua herbivory suggests a role of phenylpropanoids in oviposition-primed plant resistance.
Project description:While pathogen-induced immunity is comparatively well characterized, far less is known about plant defense responses to arthropod herbivores. To date, most molecular-genetic studies of plant-arthropod interactions have focused on insects. However, plant-feeding (phytophagous) mites are also pests of diverse plants, and mites induce different patterns of damage to plant tissues than do well-studied insects (e.g., Lepidopteran larvae or aphids). The two-spotted spider mite, Tetranychus urticae, is among the most significant mite pests in agriculture. T. urticae is an extreme generalist that has been documented on a staggering number of plant hosts (more than 1,100), and is renowned for the rapid evolution of pesticide resistance. To understand reciprocal interactions between T. urticae and a plant host at the molecular level, we examined mite herbivory using Arabidopsis thaliana. Despite differences in feeding guilds, we found that transcriptional responses of A. thaliana to mite herbivory generally resembled those observed for insect herbivores. In particular, defense to mites was mediated by jasmonic acid (JA) biosynthesis and signaling. Further, indole glucosinolates dramatically increased mite mortality and development times. Variation in both basal and activated levels of these defense pathways might also explain differences in mite damage and feeding success between A. thaliana accessions. On the herbivore side, a diverse set of genes associated with detoxification of xenobiotics was induced upon exposure to increasing levels of in planta indole glucosinolates. Our findings provide molecular insights into the nature of, and response to, herbivory for a representative of a major class of arthropod herbivores. We used microarray to assess global gene expresion in Arabidopsis thaliana upon Tetranychus urticae attack in two A. thaliana accessions: Bla-2, resistant to spider mite herbivory and Kon, susceptible to spider mite herbivory. 3 week old Arabidopsis thaliana plants were subjected to Tetranychus urticae attack through application of 10 mites for various periods of time (timecourse scenario) or hundreds of mites for 1 hour (feeding site scenario).
Project description:Effects of heat priming applied to the first generation on tolerance of the successive generation to post-anthesis high temperature stress were investigated. Compared with the progeny of non-heat primed plants (NH), the progeny of heat-primed plants (PH) presented higher grain yield, leaf photosynthesis and activities of antioxidant enzymes and lower cell membrane damage under high temperature stress. In the transcriptome profile, 1430 probes showed obvious difference in expression between PH and NH. These genes were those of signal transduction, transcription, energy, defense, and protein destination and storage, respectively.