Project description:Plant hormones involved in environmental stresses, namely abscisic acid (ABA), salicylic acid (SA), and jasmonic acid (JA), have been shown to interact with each other in a complex manner. To address the network of the hormone interactions, we have investigated the changes in expression under multiple hormone treatments, ABA+SA and ABA+JA. We chose cultured cells to remove the difference in the response to hormones among developmental cells or tissues. The cells were treated for 3hr and 24hr to see the rapid or transient response and steady-state response. The obtained data indicate that ABA and SA affect antagonistically, but these hormones affected many genes collaboratively. Indeed, according to the microarray data, there are many genes that responded only to ABA+SA. In addition, the ABA+SA responsive genes also responded to ABA+JA. These data suggest that hormone crosstalk is more complicated than expected and that more systematic analysis is required to untangle the hormone crosstalk network. To investigate the hormonal interactions, Arabidopsis T87 cultured cells were exposed to ABA, SA, or JA alone, or two hormones simultaneously, ABA+SA or ABA+JA, for 3hr and 24 hr. Comparing the data among those treatments, the relationships among these hormones were deduced.
Project description:Plant hormones involved in environmental stresses, namely abscisic acid (ABA), salicylic acid (SA), and jasmonic acid (JA), have been shown to interact with each other in a complex manner. To address the network of the hormone interactions, we have investigated the changes in expression under multiple hormone treatments, ABA+SA and ABA+JA. We chose cultured cells to remove the difference in the response to hormones among developmental cells or tissues. The cells were treated for 3hr and 24hr to see the rapid or transient response and steady-state response. The obtained data indicate that ABA and SA affect antagonistically, but these hormones affected many genes collaboratively. Indeed, according to the microarray data, there are many genes that responded only to ABA+SA. In addition, the ABA+SA responsive genes also responded to ABA+JA. These data suggest that hormone crosstalk is more complicated than expected and that more systematic analysis is required to untangle the hormone crosstalk network.
Project description:Salicylic acid (SA) and jasmonic acid (JA) fulfill key signaling functions in plant responses to herbivores. However, the mechanisms that facilitate systemic signaling in response to phloem-feeding insects remain poorly defined. Rapid local and systemic transcriptome reprogramming patterns observed in Arabidopsis thaliana following infestation by the green peach aphid (Myzus persicae Sulzer) identify abscisic acid (ABA) and redox-signalling as key factors in the transmission of signals from local to systemic leaves. Moreover, aphid fecundity was increased in mutants that were defective in ABA-signaling through ABA-INSENSITIVE 4 and show constitutive up-regulation of SA- and JA-mediated defense pathways. Conversely, aphid fecundity was decreased and aphid vigor was impaired on vitamin C2 mutants that are defective in the major low molecular weight antioxidant of plant cells, ascorbic acid and show constitutive up-regulation of redox defense and SA-mediated pathways but reduced up-regulation of JA-mediated pathways. Crossing vtc2 with abi4 restored the wild type sensitivity to aphids. Hence aphid fecundity was attenuated by low ascorbate in a manner that was dependent on the functions of the ABI4 transcription factor. ABI4 is not only an important regulator of systemic defenses against aphids but it makes a significant contribution to the SA-mediated repression of JA signaling.
Project description:Salicylic acid (SA) and jasmonic acid (JA) fulfill key signaling functions in plant responses to herbivores. However, the mechanisms that facilitate systemic signaling in response to phloem-feeding insects remain poorly defined. Rapid local and systemic transcriptome reprogramming patterns observed in Arabidopsis thaliana following infestation by the green peach aphid (Myzus persicae Sulzer) identify abscisic acid (ABA) and redox-signalling as key factors in the transmission of signals from local to systemic leaves. Moreover, aphid fecundity was increased in mutants that were defective in ABA-signaling through ABA-INSENSITIVE 4 and show constitutive up-regulation of SA- and JA-mediated defense pathways. Conversely, aphid fecundity was decreased and aphid vigor was impaired on vitamin C2 mutants that are defective in the major low molecular weight antioxidant of plant cells, ascorbic acid and show constitutive up-regulation of redox defense and SA-mediated pathways but reduced up-regulation of JA-mediated pathways. Crossing vtc2 with abi4 restored the wild type sensitivity to aphids. Hence aphid fecundity was attenuated by low ascorbate in a manner that was dependent on the functions of the ABI4 transcription factor. ABI4 is not only an important regulator of systemic defenses against aphids but it makes a significant contribution to the SA-mediated repression of JA signaling.
Project description:Arabidopsis thaliana has been used regularly as a model plant in gene expression studies on transcriptional reprogramming upon pathogen infection, such as that by Pseudomonas syringae pv. tomato DC3000 (Pst DC3000), or when subjected to stress hormone treatments including jasmonic acid (JA), salicylic acid (SA), and abscisic acid (ABA). RT-qPCR has been extensively employed to quantitate these gene expression changes. However, the accuracy of the quantitation is largely dependent on the stability of the expressions of reference genes used for normalization. Recently, RNA-seq has been widely used to mine stably expressed genes for use as references in RT-qPCR. However, the amplification step in RNA-seq creates an intrinsic bias against those genes with relatively low expression levels, and therefore does not provide an accurate quantification of all expressed genes. In this study, we employed mass spectrometry-based label-free quantification (LFQ) in proteomic analyses to identify those proteins with abundances unaffected by Pst DC3000 infection. We verified, using RT-qPCR, that the levels of their corresponding mRNAs were also unaffected by Pst DC3000 infection. In addition, using RT-qPCR, we verified that the mRNAs were stably expressed upon stress hormone treatments including JA, SA, and ABA. Results indicated that the candidate genes identified here had stable expressions upon these stresses and are suitable to be used as reference genes for RT-qPCR. Among the 18 candidate reference genes reported in this study, many of them had greater expression stability than the commonly used reference genes, such as ACT7, in previous studies. Here, besides proposing more appropriate reference genes for Arabidopsis expression studies, we also demonstrated the capacity of mass spectrometry-based LFQ to quantify protein abundance and the possibility to extend protein expression studies to the transcript level.
Project description:FERONIA (FER) is a plasma membrane-localized receptor-like kinase (RLK) that belongs to the Catharantus roseus RLK1-like (CrRLK1L) subfamily. FER serves as a potential cell wall sensor that regulates multiple phytohormones, including ABA, JA, SA, BR, auxin, and ethyl, but the underlying regulatory mechanisms are still largely unknown. To further understand how FER regulates downstream signaling pathway, we performed FER-interacting proteins via immunoprecipitation-mass spectrometry (IP-MS) assay generated from FER-GFP transgenic plants.
Project description:To investigate the relationships between hormones and critical components in tea leaves during withering process, we detected the alterations of abscisic acid (ABA), salicylic acid (SA), and jasmonic acid (JA), catechins, theanine, and caffeine in tea leaves withered at different time points from 0 to 24 hours. The content of ABA increased from 0h to 9h and decreased thereafter and JA content continuous increased, however, SA content was no significantly changes during withering process. Except for gallocatechin (GC) and epicatechin (EC), the contents of other critical components were significantly reduced at 24h. Transcriptome analysis shown that compared with 0h, a total of 2,256, 3,654, and 1,275 differentially expressed genes (DEGs) were identified at 9h, 15h, and 24h, respectively. The pathways of“Phenylalanine, tyrosine and tryptophan biosynthesis”, and “Phenylalanine metabolism” involved in biosynthesis of catechins were enriched significantly with DEGs of all comparisons. Weighted correlation network analysis (WGCNA) of co-expression genes indicated that many of modules were correlated with a specific trait only, however, the darkolivegreen module were correlated with two traits ABA and theanine during withering process. Our study indicates that withering induced dramatic alteration of the gene transcription, hormones (ABA, JA, and SA) and important components, and ABA may regulate theanine matebolism during this process.